Version May 2024
INTRODUCTION — Reconstructive surgery may be needed to correct dysfunction of the upper extremity caused by trauma, infection, malignancy, degenerative disease, autoimmune disorders, or congenital deformities. Successful reconstruction restores both the function and appearance of the affected limb by replacing lost tissue. Microsurgery, which makes tissue transplants and tendon, muscle, and nerve transfers possible, is an important component of upper extremity reconstructive surgery. Tissue flaps are often used to provide coverage for soft tissue defects, and various types of implants and prosthetic devices can aid in these reconstructive efforts.
The principles of surgical reconstruction of the upper extremities are reviewed. In some severe cases, reconstruction will not restore the function of the affected extremities. Regardless of whether the limiting factor is the size of the injury or the overall health of the patient, primary amputation may be the best treatment. Amputation should not be regarded as a loss or failure to treat an injury. The determination of whether upper extremity reconstruction or completion amputation is more appropriate is reviewed separately. Other aspects of management of upper extremity trauma, including upper extremity amputation, and upper extremity fasciotomy are reviewed separately. (See "Severe upper extremity injury in the adult patient" and "Surgical management of severe upper extremity injury", section on 'Limb salvage versus amputation' and "Upper extremity amputation" and "Upper extremity fasciotomy techniques".)
Severe lower extremity injury and reconstruction are reviewed separately. (See "Severe lower extremity injury in the adult patient" and "Surgical management of severe lower extremity injury" and "Lower extremity amputation" and "Lower extremity fasciotomy techniques" and "Surgical reconstruction of the lower extremity".)
INDICATIONS
●Traumatic injuries – Traumatic injuries include open fractures, multiple tendon injuries, vascular injuries, crush injuries, traumatic amputations, and severe nerve injuries, including peripheral nerve and spinal cord injuries. Injuries, such as open fractures with large skin defects, usually require multiple combined surgical procedures. In the acute trauma phase, the initial focus is on hemostasis. The goal is to restore blood flow to limit the duration of ischemia and potential tissue loss. At times, a temporary shunt may be necessary to facilitate temporary fracture fixation before vascular repair can commence. Subsequently, ischemic or necrotic tissue will require debridement, sometimes serial debridement, before the reconstruction can take place. (See "Severe upper extremity injury in the adult patient", section on 'Initial evaluation and management' and "Surgical management of severe upper extremity injury".)
●Infection – Antibiotics, incision and drainage, and debridement are the mainstay of treatment for upper extremity infection. In cases of severe infection, multiple sequential debridement procedures may be required. Reconstructive surgery is performed after the remission of infection to aid functional recovery of the damaged limb. (See "Overview of hand infections" and "Necrotizing soft tissue infections" and "Surgical management of necrotizing soft tissue infections".)
●Degenerative disease – Degenerative diseases are mainly caused by repetitive stress and aging. One orthopedic degenerative disorder that affects the upper extremities is osteoarthritis, for which various reconstructive surgeries are performed, such as joint replacement.
For degenerative diseases that affect the central nervous system, such as spastic paralysis, arthrodesis or tendon transfers of the upper extremity can be performed.
●Autoimmune disease – Autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, also have a destructive effect on joints. Advances in disease-modifying antirheumatic drugs and biologics have increased remission rates and reduced joint destruction. In cases with residual deformities or pain, or for destroyed joints, patients may undergo reconstructive surgery. (See "General principles and overview of management of rheumatoid arthritis in adults" and "Surgical management of end-stage rheumatoid arthritis" and "Arthritis and other musculoskeletal manifestations of systemic lupus erythematosus".)
Tendon ruptures, caused by inflammation, or joint destruction affecting the site of tendon attachment can be treated with tendon transfers.
●Malignant tumor – Surgical treatment of a malignant tumor (mostly sarcoma) includes radical resection and reconstruction of the defect (picture 1). The most common treatment is covering the defect with a skin graft or flap. However, if the tumor is extensive and involves the brachial plexus and proximal vessels (subclavian, axillary), the required excision surpasses reconstructive abilities and amputation is necessary. The amputation rate following resection of upper extremity tumors is less than 20 to 30 percent [1]. Survival rates for reconstruction versus amputation are not significantly different [1,2]. (See "Surgical resection of primary soft tissue sarcoma of the extremities" and "Upper extremity amputation".)
●Congenital disease – In cases of reconstruction for congenital disease, surgeons must consider how the defect will affect the child's development [3]. Timing of the surgery is largely according to the normal developmental progress. As examples:
•Reconstruction of polydactyly is usually performed when a child is around two years old, corresponding to the development of a pinch grip. Oftentimes, children will require more than one reconstructive surgery. The deformity most commonly operated on is a Wassel type IV polydactyly with a duplicated proximal phalanx (picture 2). For this type of polydactyly, the redundant thumb is resected but the metacarpophalangeal joint of the residual thumb is reconstructed.
•Severe limb defects, such as congenital limb shortening or achondroplasia, can be treated with a lengthening operation. Such treatment improves posture and arm extension. Lengthening is performed over a span of several months, with the affected limb, including bones, vessels, and nerves, gradually extended.
GOALS AND INFORMED CONSENT — Before proceeding with reconstructive surgery, realistic goals must be set. In most cases, the available tissues for reconstruction will be limited, and, thus, a return to a normal state will not be feasible, which needs to be conveyed to the patient. Expectations for recovery should also be discussed to avoid disappointment, particularly if there are any anticipated residual aesthetic or functional deficits.
While it is always desirable to avoid multiple surgeries, some situations will require multiple operations because of the nature of the operation, the patient's age, or the extent of the patient's injury or defect [4,5]. For the upper extremity, one study found that the average number of reconstructive surgeries performed per patient was three [5]. Older patients are likely to have longer recovery periods [4].
Unexpected problems can be encountered during any surgery, and the surgeon must have alternative plans to accommodate for them. It is important that the patient is informed beforehand about all possible treatment paths.
PREOPERATIVE EVALUATION AND PREPARATION — The surgeon must estimate the extent of required resection and plan reconstructive steps after thorough clinical evaluation including history and physical examination and preoperative imaging, which may include radiographs or computed tomography of the extremity. Evaluation and preparation and medical risk assessment varies depending upon the specific indication for upper extremity reconstruction.
●Upper extremity trauma (see "Severe upper extremity injury in the adult patient", section on 'Initial evaluation and management' and "Severe upper extremity injury in the adult patient", section on 'Management approach')
●Degenerative or rheumatic disease (see "Preoperative evaluation and perioperative management of patients with rheumatic diseases" and "Evaluation of cardiac risk prior to noncardiac surgery")
●Malignancy (see "Preoperative evaluation and management of patients with cancer")
●Congenital problems (see "General anesthesia in neonates and children: Agents and techniques", section on 'Patient and parent or caregiver preparation for anesthesia')
BONE STABILIZATION AND RECONSTRUCTION — Stabilization of the bone structure constitutes the foundation of reconstruction surgery of the extremity. Simple fractures can be easily stabilized by performing osteosynthesis. Bone defects and avascular bone fragments are often seen in severe injury and can cause nonunion of the fracture and osteomyelitis. For the success of the bone reconstruction, the surgeon should preserve vascularized bone fragments, aggressively debride avascular or contaminated fragments, and compensate for bone defects by grafting.
Fracture stabilization — If necessary, the bones and joints must be stabilized before reconstructing other tissues (algorithm 1). The stability of a joint can be determined by observing the joint during active motion. The evaluation of any affected joints should include an examination for injuries to the cartilage or ligaments, as well as joint instability and movement-induced pain.
The principal goal of fracture stabilization is to permit early active and passive range of motion exercises to prevent tendinous adhesions and joint contractures. External fixation devices, plates, intramedullary nails, Kirschner wires, and soft wires are used to stabilize fractures. External fixation is mostly used as a temporary measure.
Secure unification of bone fragments leads to stabilization of a fracture. Precise alignment, leaving no gaps between the fragments, is essential for effective healing. If there is a gap, scar tissue will form, which hinders bone healing, ultimately leading to a nonunion. Bone defects are managed with grafting. (See 'Bone grafting' below.)
The basic principles of management of specific upper extremity fractures are provided separately (predominantly for individual, closed fractures).
●As long as the displacement of the fragments of the fracture is small or manually reducible, most isolated proximal and midshaft humeral fractures can be treated with a cast. However, with the reconstruction of multiple injuries, these fractures are treated with fracture stabilization procedures that include intramedullary nails and locking plates. On the other hand, distal humeral fractures are usually treated with locking plates regardless of the degree of displacement since the fracture site is vulnerable to shear force, and nonsurgical treatment for the fracture can result in nonunion. Surgical stabilization enables the patient to mobilize the elbow early, preventing nonunion and joint contracture of the elbow joint. (See "Proximal humeral fractures in adults" and "Midshaft humerus fractures in adults".)
●Long-term casting (more than three weeks) can cause contracture of the forearm and the elbow. Therefore, forearm fractures should be stabilized with surgical treatment, with the exception of stable or non-displaced fractures. Locking or non-locking plates are mainly used for the stabilization of the fracture. (See "Radial head and neck fractures in adults" and "Midshaft ulna and radius fractures in adults" and "Distal radius fractures in adults".)
●In the hand, plates are used with caution for the stabilization of phalangeal fractures because they can cause tendinous adhesions. Stabilization with wires or screws is preferred [6,7]. (See "Overview of finger, hand, and wrist fractures" and "Overview of metacarpal fractures" and "Overview of carpal fractures".)
Closing bony gaps
Bone grafting — Bone grafting is the most commonly used procedure to close gaps between bone fragments [8]. Several types of bone grafts are available, including autologous grafts (or autografts), allogenic graft, and synthetic grafts. All bone grafts are used to serve as a scaffold to fill gaps with new bone growth, a process referred to as osteoconduction. In addition, autografts and allografts trigger osteoinduction, which is the formation of new bone through the differentiation of osteoprogenitors into osteoblasts. Autografts are the most commonly used bone graft for their osteoinductive and osteoconductive properties [8,9].
Autografts include nonvascularized (or free) and vascularized bone grafts. With nonvascularized bone grafting, the surgeon harvests only the bone, whereas with vascularized bone grafting, the bone is harvested along with the artery and vein, which are anastomosed with the arteries and veins in the recipient site.
●Nonvascularized grafts for upper extremity reconstruction are mainly harvested from the anterior iliac crest, the distal radius, or the proximal ulna. A relatively large amount of bone can be collected from the posterior iliac crest, but this requires an intraoperative change of the patient's position. Nonvascularized bone grafting is performed by placing the cancellous bone and cortical bone in the gap between the fragments.
●A large vascularized autograft is used for defects of 6 cm or more and can be harvested from the fibula, the lateral border of the scapula or the iliac crest (picture 3) [10,11].
Bone shortening — Bone shortening is another method that can be used to close gaps for many upper arm and forearm fractures [12]. However, excessive shortening can result in weak muscles because the muscles are longer relative to the bone. The maximal length of bone shortening of the upper arm reported in the literature ranges between 4 and 5 cm [13-16].
Ideally, defects in forearm bone should be compensated by the bone grafting, rather than shortening. Inappropriate shortening can easily decrease in the length of the lever arm and limit range of motion and strength; thus, shortening should be performed judiciously. Shortening less than one centimeter may not affect forearm rotation, but surgeons cannot preoperatively estimate the range of forearm rotation that will occur after the shortening.
Open fractures — Open fractures are more difficult to treat and have limited functional results compared with closed fractures because of the increased risk for nonunion, deformity, and infection [17-19]. Definitive fixation and defect coverage with a soft tissue flap, or the "fix and flap approach," is aggressively performed for open fractures in the upper extremity [10,11]. This approach facilitates fracture repair and helps prevent nonunion with the vasculature provided by the flap. (See 'Soft tissue coverage' below.)
Repair of nonunions — The treatment of nonunion depends on how the initial injury occurred (algorithm 2). Causes of nonunion include inadequate fixation of bone fragments, poor bone healing, or a combination of both.
●Hypertrophic nonunion – Hypertrophic nonunion is due to inappropriate fixation. Radiography of this type of nonunion shows a hyperplastic callus. Hypertrophic nonunions can be treated adequately with internal fixation fortified with extra plating or exchanging an existing intramedullary nail with a thicker one.
●Oligotrophic nonunion – Oligotrophic nonunion (or atrophic nonunion) is due to poor bone healing. Imaging shows atrophy of bony structures around the injury site [20]. The healing of the fracture ultimately ceases because the surrounding soft tissue fills in the gaps between the bone fragments, disrupting fracture union. Thus, for oligotrophic nonunion, tissue curettage and bone grafting are performed to stimulate healing.
Other options
Ilizarov technique — The Ilizarov technique corrects upper extremity deformities through the extension of bone and soft tissue, including nerves, blood vessels, and muscles. The Ilizarov external fixator is multiplanar and simultaneously extends the bones and various tissue types at a pace of approximately 1 mm per day. Although the Ilizarov technique is commonly used for lower extremity injuries, it is being applied to upper extremity injuries such as nonunions, various deformities from trauma or infection, and malformations from congenital diseases and benign bone tumors [21-24]. It is usually difficult to make subtle adjustments with an Ilizarov fixator. Thus, Taylor Spatial Frames (TSFs) have been developed, which use computerized calculations to assist in a more refined and precise extension of the upper extremity [25]. Moreover, TSF is often used for the bone transplantation, which can fill a massive bone defect without a vascularized bone graft (figure 1) [25].
Masquelet technique — The Masquelet technique is a length-independent technique that is used for bone reconstruction following osteomyelitis. As described above, engraftment of a bone defect longer than 6 cm requires a vascularized bone graft. However, reconstruction using the Masquelet technique does not require a vascularized bone graft, even with a large defect. With this technique, coverage with the vascularized flap promotes the consolidation of the nonvascularized cancellous bone autograft by induction of the periosteal membrane [26].
This two-stage procedure is usually performed on the lower extremities but has been adapted for the upper extremities.
●In the first stage, infection is cleared with debridement until bleeding occurs from the bone marrow, and the bone is stabilized via external or internal fixation. Cement beads, or methylmethacrylate, are inserted into the bone defect as a spacer, then the wound is covered with skin or soft tissue flaps [27]. These spacers induce a membrane made of a type 1 collagen-rich matrix containing fibroblasts at the site of the bone defect. The membrane contains osteogenic factors that promote bone ingrowth and osteoinduction [27-29]. If the wound is severely contaminated and at a high risk of infection, debridement may need to be repeated several times before moving to the second stage.
●The second stage (usually the four weeks after the first surgery) involves nonvascularized autogenous bone grafting [26,30-32]. Excellent results of seven nonunion cases in the forearm treated with the Masquelet technique have been reported [33].
JOINT RECONSTRUCTION — The goal of joint reconstruction is mobility and stability, with a smooth articular surface and appropriate ligamentous structures. In addition, the reconstructed joint requires soft tissue coverage to promote healing [34,35]. Joint reconstruction procedures are categorized into reconstruction of the defective tissues, joint transplants, and arthrodesis. The procedures selected are based on the affected joint and the amount of tissue loss. As an example, an elbow injury with a small osteochondral and skin defect may be repaired by combining an osteochondral transplant with a flap. On the other hand, injuries involving the loss of joint structures, such as cartilage, ligament, and the capsule, may indicate the need for prosthesis.
Joint stabilization — The approach for joint stabilization depends on the presence or absence of residual ligaments. If there are residual ligaments, they can be reattached to the bone using suture anchors.
Grafts for ligament reconstruction of the fingers are harvested from the extensor retinaculum or a part of a flexor digitorum superficialis. Ligament reconstruction in the metacarpophalangeal joint of the thumb, the intercarpal joints, and the elbow is usually performed with the palmaris longus tendon graft.
The tension of the ligament is very important to the overall quality of stabilization; a strained ligament reduces the range of motion, while a loose ligament causes joint instability.
When there is a loss of ligament and articular capsule, an external fixator with a hinge component is used. This encourages the regeneration of soft tissue without impairing the patient's ability to move the injured joint.
Cartilage reconstruction — Procedures for cartilage reconstruction are selected depending upon the degree of injury, which is classified by the International Cartilage Repair Society (ICRS) grading system [36].
●For relatively small defects of articular cartilage corresponding to ICRS grades 1 to 2, debridement of the peeled cartilage or fixation of the delaminated cartilage by bone pegs is performed. For small defects of the elbow joint, microfracture techniques are also used. With this technique, several holes are made in the cartilage and the discharged blood forms a clot, allowing the pluripotent cells within the clot to mature into fibrocartilage over time.
●Cartilage defects corresponding to ICRS grades 3 to 4 are an indication for an osteochondral autograft or autologous cartilage implantation (ACI). Autologous osteochondral transplantation is the most common procedure for the reconstruction of cartilage in the upper extremity. The donor site of an osteochondral graft differs according to the size of bone loss.
•For small defects, the graft is harvested from the pisiform [37], or the carpometacarpal joint surface of the hamate [38,39].
•For moderate-to-large defects, the unloaded portion of the medial or lateral femoral condyle in the knee [40], costal cartilage [41], or proximal tibiofibular joint [42] is harvested.
ACIs have an advantage over osteochondral grafts. ACI transplants cultivated chondrocytes to the defected area. More than 60 percent of the implanted cartilage ultimately changes into hyaline cartilage, eliminating the risk of breakage [43]. With ACIs, the reconstructed cartilage functions as a hyaline cartilage, which can tolerate the load of the arm more than fibrocartilage. ACI is an established procedure for the knee joint. However, there have been reports of a few successful treatments in the humeroradial joint and the radiocarpal joint [44].
Joint transplantation — If multiple joint components are missing, joint transplantation is usually performed. Joint transplantation from the toes has been used for reconstruction of the proximal interphalangeal (PIP) joint and the humeroulnar joint [45,46]. However, the indications for this procedure may limit the use to only a few patient groups, such as children.
The PIP joint of the toe is harvested with the cartilage, the capsule, ligaments, tendons, and tendon sheathes. It is subsequently transplanted with anastomoses of its vascular pedicle. These grafts are particularly useful in pediatric patients because the growth plate is conserved. However, the reconstructed joint will regain only a limited range of motion. A retrospective study of the reconstruction of post-traumatic osteoarthritis of the PIP joint reported that the range of motion achieved with a vascularized toe joint transfer was less compared with silicone arthroplasty [47].
Joint replacement — Prosthetic joint replacement is performed mainly on large joints, such as the shoulder, elbow, and wrist. However, it can be performed in smaller joints, such as the carpometacarpal (CM) joint of the thumb and metacarpophalangeal (MP) and PIP joints of the fingers.
Prostheses are classified into surface replacement, semi-constrained, and constrained. In surface replacement arthroplasties, existing ligament function is essential. On the other hand, there does not have to be full ligament function to proceed with semi-restrained or constrained prostheses. However, constrained prostheses have an increased risk of breakage of the hinge mechanism [48].
Prosthetic arthroplasty in the upper extremity is performed to repair severe joint destruction in osteoarthritis, rheumatoid arthritis, and joint defects from extensive tumor resection. (See "Surgical management of end-stage rheumatoid arthritis".)
However, prosthetic arthroplasty for post-traumatic deformities is still uncommon because of a lack of data demonstrating efficacy. Primary prosthetic arthroplasty has been used for fractures of the elbow joint. Several reports suggest satisfactory outcomes of prosthetic arthroplasty for comminuted distal humerus fractures in the older adults [49-51]. In addition, post-traumatic surface replacement of the MP joint of the fingers has been reported with satisfactory results [52].
Although prosthetic arthroplasty in the upper extremities provides sufficient pain relief and useful range of motion of the affected joint, it is beyond technology to restore the joint to its initial state. In addition, complications are common, particularly loosening of the implant over time. Therefore, long-term follow-up after the surgery is required, and whenever possible, other procedures should take precedence over prosthetic arthroplasty. (See "Surgical management of end-stage rheumatoid arthritis".)
Arthrodesis — Arthrodesis refers to the fusion of bones in a joint and involves resection of the cartilage and immobilization of the joint with wiring or plating. This procedure is performed when stabilization takes precedence over mobilization.
Accordingly, shoulder joints, elbow joints, and the PIP joint of the fingers are not usually fused because of their necessary range of motion. However, arthrodesis is often performed in the distal interphalangeal (DIP) joint of the fingers and interphalangeal (IP) joint of the thumb because they require more stability than mobility.
Although the MP joint of the fingers and the CM joint of the thumb require mobility, arthrodesis is sometimes performed primarily for the relief of severe pain.
NERVES, MUSCLES, AND TENDONS — The extent of functional deficit of each neuromuscular unit is evaluated based on anatomical knowledge and neurologic findings. The active motion demonstrated to the examiner and any areas of dysesthesia assist in the diagnosis. In cases of severe trauma, the patient's pain and state of unconsciousness may make it difficult to evaluate their level of damage. However, nerve conduction studies and electromyography can aid the identification of the nerve lesion(s) in such cases. (See "Overview of upper extremity peripheral nerve syndromes", section on 'Overview of diagnostic testing' and "Traumatic peripheral neuropathies", section on 'Evaluation'.)
Nerve repair/reconstruction — Nerve recovery following reconstruction is the most difficult and unpredictable process in reconstructive extremity surgery. Nerve recovery can depend on factors such as the degree of lesions at the microscopic level and the injury site, or even factors that are indirectly related to the surgery, such as the patient's age [53]. These factors must be taken into consideration during surgery, and the patient must be informed that there is some risk involved before proceeding.
The timing of nerve reconstruction also affects the outcome of the surgery (algorithm 3): primary nerve repair is performed within three weeks of the injury while secondary repair is performed three weeks after the injury. Secondary repair is a challenging surgery because of the required removal of neuromas formed at the nerve stumps and careful release of the neuron from the perineural scarring formed during the healing process.
Although an early nerve repair is ideal, there are some cases when the condition of the wound is not suitable for the healing of the nerve. As an example, nerve recovery is inhibited when necrotic tissue is present in the vicinity of the nerve. However, once the wound is adequately debrided, and the repair can take, appropriate coverage of the affected nerve with well-vascularized soft tissue maximizes recovery (picture 4).
When an early repair is not performed, reconstruction can be challenging because of progression of muscular atrophy. Therefore, nerve reconstruction should ideally be performed within three to six months after the injury. If more than approximately one year has passed since the injury, an irreversible degeneration of the neuromuscular junction may have occurred. Even with nerve repair or neuron transfer, it will no longer be possible to reproduce muscle contractions. In these cases, the neuromuscular unit should be reconstructed via tendon transfers or muscle tendon transfers.
Procedures for nerve repair — Procedures that treat nerve disorders include neurolysis and nerve repair with or without grafting (algorithm 3).
Neurolysis — Neurolysis is a procedure that releases the nerves from blockage to relieve pain. Some forms of nerve blockage include neoplastic lesions, scars, or adhesions formed by inflammation. In cases of trauma, neurolysis is sometimes performed to release the nerve sandwiched between the bone and soft tissue.
Nerve repair with or without grafting — If the nerve is transected, suturing, with or without a graft, is the only way to treat the injury. The suturing of severed nerves is an intricate procedure that is usually done under a microscope for delicate examination. With this process, the stumps must be connected with appropriate tension; too much tension inhibits the recovery of conduction and can cause the nerve to re-rupture. The technique involves connecting individual bundles of axons within the nerve. If there is a large space between the severed ends, a nerve conduit or a graft is used to bridge the stumps.
Nerve conduits — Various conduits are available for this procedure, with the autologous vein graft being the most common. However, other conduits can be used, such as nonbiological conduits, which are made of silicon-containing collagen, polyglycolic acid, and polylactic acid in the lumen.
Satisfactory clinical results have been reported for the use of conduits with a gap of 3 cm or less in the hand and forearm [54,55]. With longer nerve conduits, the outcomes of the reconstruction are worse [56,57]. Thus, many surgeons will use biological grafts, such as autologous grafts or allografts, for gaps longer than 3 cm (picture 4) [56,57].
Nerve grafts — Either nonvascularized or vascularized nerve grafts can be used. Autologous grafts provide a scaffold containing Schwann cells and neurotrophic factors that promote nerve restoration. Usually, the harvested graft is selected based on the thickness of the recipient nerve. The sural nerve and the medial antebrachial cutaneous nerve are commonly used. Because allogeneic nerve transplantation requires immunosuppression for up to two years, these are much less common.
Vascularized nerve grafts can be used for defects of 10 cm or more in length [58]. Ischemia of the graft, which causes central necrosis and intraluminal fibrosis, can be avoided using vascularized nerve grafts, which maintain blood supply through the anastomosed vascular pedicle during transplantation. Several animal studies have demonstrated the reinforcement of axon regeneration due to the blood supply of vascularized nerve grafts [59,60].
Nerve transfers — Nerve transfers involve the transfer of a healthy donor nerve to reconstruct the affected neuromuscular unit. Nerve transfers are performed when the site of nerve injury is located far from the neuromuscular junction of the muscle. Some examples of this type of injury are high ulnar nerve, brachial plexus, and spinal cord injuries [61].
Typically, nerve transfer is performed by suturing the distal stump of the donor nerve to the proximal stump of a paralyzed recipient nerve in an end-to-end fashion. Other times, suturing end-to-side is performed while preserving the continuity of the recipient nerve. Commonly referred to as a supercharged nerve transfer or supercharged end-to-side transfer (SETS), the donor nerve facilitates the growth of the recipient's regenerated axons. SETS can be combined with the repair of the damaged area by nerve suture or neurolysis. Once the repair of the original site of the injured nerve regenerates, it leads to "dual innervation" with the nerve sutured for supercharge.
Donor nerves are usually chosen from the nerves that produce a similar motion as the injured nerve upon innervation [62]. However, this is not mandatory, because the patient can acquire control of the muscle reinnervated gradually through postoperative biofeedback training. The donor nerve should be selected from one that is located near the recipient nerve because recovery is accelerated if the attachment site is close to the recipient nerve's neuromuscular junction. Also, the sacrifice of the muscle that the donor nerve innervates should be minimized.
There are a few common nerve transfers for the upper extremity:
●The motor branch of the ulnar nerve can be transferred to the musculocutaneous nerve to restore elbow flexion. Commonly known as the Oberlin transfer, this procedure is performed at almost the center of the brachium, where both donor and recipient nerves are located close to one another [63,64].
●An intercostal nerve or phrenic nerve can be used to restore elbow flexion in brachial plexus injuries. However, inappropriate phrenic nerve transfers can cause severe respiratory complications.
●In cases of shoulder lesions, the terminal branch of the accessory nerve can be transferred to the suprascapular nerve to reconstruct the supraspinatus and infraspinatus muscles. In conjunction with the Oberlin transfer, this procedure is often performed for shoulder and elbow reconstruction of patients with severe birth brachial plexus injuries.
●During supercharged nerve transfers, the distal portion of the anterior interosseous nerve (AIN) is transferred to reconstruct the ulnar nerve [65]. High ulnar nerve injuries, including severe cubital tunnel syndrome (ie, entrapment neuropathy of the ulnar nerve), require a longer time for the axons to reinnervate the intrinsic muscles because of the long distance between the injury site and the neuromuscular junction. AIN can be transferred to the ulnar nerve to augment the regeneration of the axons and reinnervation of the muscles before the nerve axons degenerate. AIN transfers to the ulnar nerve are performed with end-to-end sutures or SETS transfers. Some suggest that SETS, which allows dual innervation, is more advantageous than the end-to-end suture [66,67].
●Nerve transfers can also be performed for the treatment of spinal cord injuries. Traditionally, patients with C5, C6, and C7 spinal cord injuries have been treated with tendon transfers. Nerve transfers are rarely performed because of the difficulty to estimate the function of the residual nerves after spinal cord injuries. In one prospective study of the nerve transfer for the spinal cord injury, functional results of patients who received nerve transfers were comparable to those who received tendon transfers [61]. Furthermore, the authors emphasized that nerve transfers reconstruct multiple muscles, whereas tendon transfers reconstruct only one tendon or muscle.
Brachial plexus injury — Patients with brachial plexus injury (BPI) acquire many functional deficits of their upper extremities. The limited amount of tissue available for reconstruction inhibits the full restoration of function. BPI is classified into two categories: preganglionic and postganglionic, which can be discriminated with a myelogram or magnetic resonance imaging (MRI). (See "Surgical treatment of brachial plexus injuries".)
●Preganglionic – The nerves in preganglionic BPI are avulsed from the spinal cord, which makes the suture repair of the nerve impossible. Reconstruction consists of a combination of nerve and muscle-tendon transfers [62,68]. In addition, reconstruction of elbow motion in preganglionic BPI is sometimes accomplished using a procedure that fuses the shoulder joint. The shoulder arthrodesis stabilizes the upper extremity and augments elbow flexion power [69]. A transferred gracilis muscle functions as a biarticular muscle for elbow flexion.
●Postganglionic – Postganglionic BPI is usually treated with nerve grafting. However, cases that involve a lapse of more than six months after the injury are treated with muscle-tendon transfers.
Tendon and muscle repair/reconstruction — For successful reconstruction of tendon injuries, tendons are sutured strongly together. When direct suture repair is not an option, tendon grafting or tendon transfers serve as alternative procedures. (See 'Tendon grafting' below and 'Tendon transfer' below.)
After repair, the tendons should demonstrate smooth excursion through the tendon sheath. Ideally, the patient will be able to produce motion soon after the operation, while preventing tendon adhesion to the surrounding connective tissue. Flexor tendon adhesions are problematic because they impede the flexing power and range of motion of the fingers. Adhesions are more likely to occur in the zone extending from the distal palmar crease to the middle phalanx (zone 2), where the tendon passes between pulleys [70]. Furthermore, if the tendon injury is accompanied with fracture or skin damage, the risk of postoperative tendon adhesion will increase.
Injuries that involve functional deficits of both the flexor and extensor tendons of the forearm are treated with multistage surgery; extensor tendons are repaired only after the flexor tendons have recovered in strength and function. It is difficult to perform postoperative rehabilitation of the flexor and extensor tendons simultaneously. If simultaneous repair were performed, postoperative rupture or loosening of the reconstructed extensor tendons could occur during healing because of the strength of the flexor tendon.
Tendon grafting — Tendon grafting brings together the injured or dysfunctional site of the tendon. It is usually performed after failed tendon repairs, neglected tendon ruptures, or severe tendon damage accompanied by fractures and soft tissue injuries.
Tendon grafting is classified as primary tendon grafting, or staged tendon grafting, if the tendon sheath is damaged. The graft is usually harvested from the palmaris longus tendon.
Reconstruction of the extensor tendons is usually with primary tendon grafting. Primary grafting connects the graft and the stump of the tendon with interwoven sutures, which provide sufficient strength to allow for early exercise. The extensor tendons are normally pulled to the digital bones by the interosseous muscles and ligaments such as the oblique retinacular ligament. In addition, the extensor retinaculum in the wrist joint widely presses the tendons to the volar side. Because all of these structures are usually not injured at the same time, reconstruction of the tendon sheath is rarely necessary. The distal stump and the graft are sutured together first, followed by the suturing of the proximal stump and graft. Suture tension is adjusted as needed during the procedure. Ultimately, the overall outcome of the procedure can be tested by observing the passive motion of the tendon. Primary grafting should not be used in cases involving extensive tendon adhesions, failure of primary repair, or underlying fractures and severe skin damage.
Reconstruction of flexor tendons depends on the condition of the patient's tendon sheath. If the tendon sheath is intact, primary repair can be performed. But without tendon sheaths, the fingers cannot fully flex. Thus, if the tendon sheath needs to be repaired, reconstruction proceeds through two stages: tendon sheath reconstruction, followed by tendon grafting [71].
●In the first stage, joint contractures and adhesions are removed, and a silicon tendon rod is inserted into the residual tendon sheath to encourage its formation (picture 5). The silicon tendon rod is fixed to the distal part of the remaining tendon or the distal phalanx. The surgeon can confirm function of the tendon sheath by pulling the fixed rod from the proximal side. If there are any defects or dysfunctions of the tendon sheath, a graft is used to form the tendon sheath.
●After formation of the tendon sheath (generally after 6 to 12 weeks of the first-stage operation), the second stage is performed by replacing the rod with an autogenous graft (picture 5). However, several complications, such as silicon tendonitis, rod deformity, and infection, may occur in cases using silicon tendon rods [72].
Tendon transfer — Different from tendon grafting, tendon transfers completely restore the distal tendon attachment of normal neuromuscular units. Therefore, the patient must relearn how to contract the transferred muscle through cortical remapping to reacquire the intuitive muscle motion [73,74].
Common examples of tendon transfers include the extensor indicis proprius tendon transfer, following an old extensor pollicis longus tendon injury, and extensor tendon transfer, following multiple extensor ruptures in rheumatoid arthritis.
In addition to tendon ruptures, tendon transfers can be used to treat cases of nerve injury. As described above, acceptable functional recovery after a nerve repair is difficult. Palmaris longus tendon transfers are performed as an opponensplasty for low median nerve palsy in which a long time has passed since the onset. (See 'Nerve repair/reconstruction' above.)
Some principles that should be followed when planning tendon transfers include the following [75]:
●The donor muscles must have sufficient contractile power to enable the effective excursion of the recipient tendon.
●Both the donor and recipient tendons should have a straight line of pull, which minimizes the loss of transferred force.
●The donor muscle must be synergistic to the recipient, such as finger extension and wrist flexion. Synergistic muscles facilitate the cortical remapping process in order to ensure intuitive muscle motion.
●The suture tension needs to be strong enough for adequate joint motion, but not to the point that it will inhibit the antagonistic motion of the joint.
Muscle-tendon transfer — Muscle-tendon transfers are performed when there is a severe muscle defect or unsatisfactory recovery of a damaged nerve. Muscle-tendon transfer differs from tendon transfer in that it shifts the neuromuscular units, including the muscles, as a vascularized flap. It can be performed as a pedicled muscle transfer, which does not require the dissection and anastomoses of the vessel and nerves, or a free muscle transfer.
A pedicled muscle transfer graft is mainly harvested from the latissimus dorsi, and a free muscle transfer graft is usually harvested from the gracilis muscle. With a pedicled muscle transfer, there is an immediate possibility of contraction because the nerve innervating the transferred muscle is not dissected. Following a free muscle transfer, it takes several months to obtain autonomic contraction of the muscle, even if properly treated. Therefore, postoperative passive exercise is important to prevent adhesions and contractures.
VASCULAR RECONSTRUCTION — Surgical procedures to revascularize the upper extremity are discussed separately. (See "Surgical and endovascular techniques for aortic arch branch and upper extremity revascularization".)
The extent of arterial injury in crushed limbs or those suffering traumatic amputation is often more severe that it appears upon first inspection. The injured arteries may have damage that causes thrombosis after the anastomosis. Therefore, in such injuries, extensive excision of the arteries near the wound is required for the success of the reconstruction. If the damaged area of the artery cannot be identified clearly, an arteriography helps the decision of the resection.
Arterial reconstruction needs to be completed without tension. If the reconstructed vessel is expected to be strained, an interposition graft should be used. Depending upon the size of the artery to be reconstructed, a vein graft can be harvested from the saphenous vein, cephalic vein, or the dorsal veins of the hand (picture 6). The radial artery may also be available for vascular grafting, but it is rarely needed.
Arterial defects with a concurrent soft tissue defect can be reconstructed with a "flow-through flap" [76]. Moreover, bone shortening described previously can substitute for bone grafting. As an example, extremity replantation, which involves arterial reconstruction, is usually performed with bone shortening.
Most extremity venous injuries can be treated with ligation, but the major deep veins should be repaired to prevent extremity edema distal to the injured site. Veins should also be reconstructed in degloving injuries to prevent venous decongestion in the flap.
Compartment syndrome should be monitored after arterial reconstruction to the ischemic limb. Reperfusion exacerbates the edema with the production of free radicals, which is a cause of compartment syndrome. A reperfused limb with ischemia for more than three hours should undergo a prophylactic fasciotomy. (See "Acute compartment syndrome of the extremities" and "Upper extremity fasciotomy techniques".)
SOFT TISSUE COVERAGE — Appropriate coverage of the bone or joint with soft tissue is one of the most important steps in reconstructive surgery [34].
Timing of soft tissue coverage — Wound coverage facilitates healing of the reconstructed structure with sufficient blood supply, allowing the patient to begin physiotherapy. However, wound coverage is generally performed once the wound bed is clean and well prepared, which may require several rounds of debridement. (See "Basic principles of wound management", section on 'Wound debridement'.)
With traumatic wounds, some authors have reported the superiority of early free flap coverage [34,77]. Alongside early free flap coverage, internal fixation is also performed for many open fractures with skin defects. This technique is referred to as the "fix and flap approach" [11]. When it is possible, it is the most rational treatment. However, there are only a limited number of hospitals that have the technology and skills to use this technique. (See 'Bone stabilization and reconstruction' above.)
Grafts and flaps for reconstruction — Wound coverage uses a variety of methods that include simple wound closure, skin grafting, and various flaps. The selection is based on the concept of the "reconstructive elevator," which states that the most necessary and sufficient procedure should be selected according to the site and condition of the injury [78,79]. The different characteristics of skin grafts and flaps must be taken into consideration throughout the selection process. Between grafts and flaps, the biggest difference is vasculature. However, aside from vasculature and skin type, flaps are further classified according to the type of soft tissue. (See "Skin autografting" and "Overview of flaps for soft tissue reconstruction".)
Skin grafts cannot cover poorly vascularized tissues, such as exposed cortical bone, because they cannot provide sufficient capillary ingrowth. In addition, skin grafts are not usually used for coverage near joints or exposed tendons. The scar formed during engraftment causes dermal contractures and tendon adhesions, which decrease the range of joint motion.
Flaps for upper extremity reconstruction are selected based upon the size, appearance, and condition around the skin defect. The volume of the selected flap must match that of the recipient site for optimal functional and cosmetic aspects [80]. An excessively bulky flap hinders appearance and interferes with range of motion. One flap that is commonly used for forearm and hand reconstructions is an anterolateral thigh flap, which is harvested as a thin flap [81]. Several perforator flaps have also been used [82,83].
Large defects — A pedicled groin flap is used as a distant flap for the reconstruction of large skin defects on the hands and fingers. This type of graft is harvested easily, with a width of 10 cm and a length of 20 cm, and can cover the defect without vascular anastomoses (picture 7) [84]. However, this type of flap requires a division of the flap and has the risk of elbow and shoulder stiffness. A groin flap harvested as a free flap does not have this challenge, but the variability of vascular anatomy makes harvesting the flap more difficult.
Other free flaps from various parts of the body can be used to cover large defects. Some of these include the latissimus dorsi muscle flap, anterolateral thigh flap, and the scapula flap (may be less difficult because of the limited anatomic variation). The latissimus dorsi muscle flap is helpful for reconstructing extensive skin defects on the upper extremity but usually requires additional skin grafting on the muscle flap. Some suggest that reconstruction with muscle flap and skin graft is inferior to a cutaneous flap in terms of cosmetic appearance [85]. Anterolateral thigh flaps are also useful given their similar slimness and appearance to the forearm. This procedure can be safely performed regardless of age or smoking status. When using the flap, the surgeon should take into account the wide variability in the anatomy of the flap's perforating arteries [86].
Flaps for small defects in hand and forearm — Several regional flaps are available for forearm reconstruction. As described above, the traditional radial artery flap is reliable but can be aesthetically unappealing at the donor site [87]. Therefore, some surgeons prefer to use it as an adipofascial flap.
The posterior interosseous artery flap is used for reconstruction of the first web space because it can fill the defect with the appropriate amount of tissue while avoiding sacrifice of the radial and ulnar arteries [88].
The radial artery and ulnar artery perforator flaps are used for skin defects of the dorsal hand.
A lateral upper arm flap supplied by the radial collateral artery can be harvested for forearm reconstruction. In addition, it can be used as a pedicle or free flap for the reconstruction of the skin around the elbow (picture 2 and picture 4) [89]. Some surgeons prefer this flap because of matching skin tone.
Thumb and finger defects — Thumb and finger flaps are used to reconstruct amputations, or for defects following tumor resection. The tips of the thumb and fingers should be covered with a sufficient amount of soft and pain-free skin. Sensory perception is vital in the thumb and can be restored with a flap that contains a nerve [90].
Volar advance and kite flaps supplied by the dorsal metacarpal artery are commonly used in thumb reconstruction. A volar advance flap, which includes a digital nerve in the pedicle, is used as an innervated flap. On the other hand, a kite flap, which does not usually contain a nerve within the pedicle, can be used as an innervated flap by suturing the dorsal branch of the radial nerve included in the flap to the residual stump of the volar digital nerve.
A neurovascular flap harvested from the ring finger with the ulnar digital artery and nerve is available as a regional innervated flap [91].
For reconstruction of the fingertips, a reverse island flap, harvested from the lateral proximal region of the finger, or oblique triangular flap is used [92].
Cross-finger flaps or dorsal metacarpal artery flaps are used as regional flaps. A cross-finger flap is harvested from the adjacent finger. With this technique, the donor and recipient fingers remain attached by the flap while the capillary network is established. The two fingers are separated after approximately two weeks.
For volar or dorsal skin defects in the proximal and middle phalanx, a dorsal metacarpal artery flap is used (picture 8).
Composite tissue allografts from the toes are used to reconstruct multiple tissues simultaneously (picture 9). Toe transfer and wrap-around flaps can restore the tips, even maintaining the nail and perception of the toe [93,94].
POSTOPERATIVE CARE
Wound care — After any surgical procedure, wounds should be managed to avoid infection, which can be characterized by, but not limited to, swelling or redness. Drainage of any subcutaneous abscesses and debridement of any necrotic tissue are common ways to minimize postoperative infection.
In addition, surgeries that involved vascularized grafts or flaps must be monitored periodically to ensure a successful outcome [95]. Systemic anticoagulation is commonly used to prevent postoperative thrombosis. However, for patients with competing injuries (eg, brain trauma or severe injuries), anticoagulation may not be possible. (See "Overview of flaps for soft tissue reconstruction", section on 'Identifying vascular compromise'.)
Postoperative rehabilitation — Physiotherapy plays an important role in obtaining satisfactory results after surgical reconstruction of the upper extremity. While protecting the reconstructed extremity with splints, promoting joint motion or tendon excursion with early active and passive mobilization can prevent joint contractures and tissue edema.
The surgeon, rehabilitation staff, and patient must cooperate to ensure a successful healing process. Based on intraoperative and postoperative observations, the surgeon must thoroughly communicate the plan and goals of rehabilitation with the occupational therapist or physical therapist.
COMPLICATIONS — Complications after reconstructive surgery include deep infections, flap necrosis, tendon adhesions, joint contractures, pseudoarthrosis, chronic regional pain syndrome, and sensory disorders. The main complications that impair upper extremity reconstruction include adhesions and joint contracture.
Most tendon adhesions are avoidable with early implementation of postoperative rehabilitation. However, in cases with adhesion, tenolysis can restore the tendon excursion (picture 4). Surgeons should keep in mind that tenolysis in the immature stage in a reparative process of the tendon can cause rerupture of the affected tendon. Therefore, tenolysis should be done after no less than the four months after the primary reconstruction. Moreover, many surgeons prefer to postpone the tenolysis if the limb has been revascularized.
Most joint contractures can also be avoided with appropriate postoperative rehabilitation. Splinting in a functional position helps prevent contractures. Positions that should be avoided in the hand are flexion of the interphalangeal joints, extension of the metacarpophalangeal joints, and adduction of the thumb. When joint contractures do occur, they are treated with capsulotomy and partial resection of the tensioned ligament at the joint, but the restoration after these interventions is limited, and recurrent contracture often occurs after the revision surgery.
OUTCOMES — Although excellent treatment results have been reported for each reconstructive technique, many are based on retrospective reviews. The heterogeneity in patients' medical conditions has made it difficult to conduct prospective research to determine the usefulness of each treatment. However, even in such situations, comparative studies based on retrospective studies can serve as a guide for the reconstructive plan.
As an example, retrospective studies of traumatic major amputation have compared revision amputation and replantation, with several attempts at reconstructive surgeries [96-98]. In these cases, those who had several reconstructive surgeries after replantation had better outcomes and patient satisfaction compared with revision amputation and prosthesis [96-98]. These results may encourage the surgeons, in the face of a challenging upper extremity injury, to exert maximum efforts for limb salvage.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Extremity compartment syndrome" and "Society guideline links: Severe blunt or penetrating extremity trauma".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topic (see "Patient education: Flap surgery (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Upper extremity reconstruction – Reconstructive surgery may be needed to correct dysfunction of the upper extremity caused by trauma, infection, malignancy, degenerative disease, autoimmune disorders, or congenital deformities. Successful reconstruction restores both the function and appearance of the affected limb by replacing lost tissue. Additional surgeries may be necessary. (See 'Introduction' above and 'Indications' above.)
●Bone stabilization – Stabilization of the bone structure constitutes the foundation of extremity reconstruction. To reinforce fracture fixation, bone grafting or bone shortening may be necessary. Bone transport with the Ilizarov technique and the Masquelet procedure are options for large bony defects. (See 'Bone stabilization and reconstruction' above.)
●Joint reconstruction – Joint restoration is accomplished through several procedures, including ligament reconstruction with a graft and cartilage reconstruction with osteochondral grafts. Joint transplantation, prosthesis placement, and arthrodesis are also used for joint restoration. (See 'Joint reconstruction' above.)
●Nerve, muscle, and tendon reconstruction – Nerves, muscles, and tendons are approached as an integrated neuromuscular unit during the reconstructive process. (See 'Nerves, muscles, and tendons' above.)
•Ruptured nerves are sutured and repaired with a nerve graft.
•When the injured site of the nerve is away from the neuromuscular junction of the nerve that innervates it, nerve transfer is performed.
•Ruptured tendons are repaired by suturing the tendon stumps, and either tendon grafting or tendon transfer.
•Irreparable injuries to the neuromuscular unit, such as severe muscle defect and brachial plexus injuries, are indications for a muscle-tendon transfer.
●Vascular reconstruction – Arteries and veins are mainly restored by primary repair, interposition grafting with autologous vein, or ligation. The ischemic limb is managed postoperatively with attention to reperfusion and compartment syndrome. (See 'Vascular reconstruction' above.)
●Soft tissue coverage – The process of soft tissue reconstruction is termed "coverage," which is the ideal operation, but sometimes it is not possible. Coverage is accomplished using skin grafts, skin flaps, or muscle flaps based on the principles of the "reconstructive elevator." (See 'Soft tissue coverage' above.)
●Complications – Tendon adhesions and joint contracture are the main complications that impair reconstruction of the upper extremity. To prevent their occurrences, early mobilization and splinting is used. Postoperative adhesions and contractures are treated with tenolysis or capsulotomy. (See 'Complications' above.)
ACKNOWLEDGMENTS — The UpToDate editorial staff acknowledges Jennifer M Sterbenz, BS, and You Jeong Kim, BS, who contributed to an earlier version of this topic review.
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