Proximal phalanx fractures

INTRODUCTION — Fractures of the proximal phalanx can be complex owing to forces exerted on the fracture fragments by multiple muscles and tendons which often result in angular or rotational deformity.

This topic review will discuss fractures of the proximal phalanx. Finger anatomy, other common finger and hand injuries, and thumb injuries are all reviewed separately. (See "Finger and thumb anatomy" and "Distal phalanx fractures" and "Extensor tendon injury of the distal interphalangeal joint (mallet finger)" and "Middle phalanx fractures" and "Overview of metacarpal fractures".)

CLINICAL ANATOMY — Anatomy of special importance to proximal phalanx fractures is described below; a more detailed discussion of finger anatomy is found separately. (See "Finger and thumb anatomy".)

Proximal phalanx fractures often present with apex volar angulation. Interosseus muscles and lumbricals insert onto the base of the proximal phalanx and flex the proximal fragment. The flexor and extensor tendons impart a longitudinal compression force, which can shorten the phalanx and extend the distal fragment [1].

Both the lumbrical muscles, which originate on the tendons of the flexor digitorum profundus, and the interosseous muscles, which originate on the metacarpals, insert at or near the proximal phalanx (figure 1 and figure 2). The lumbricals are involved in flexion of the metacarpal-phalangeal (MCP) joint and extension of the interphalangeal joints of the fingers. The interossei are involved in finger abduction and adduction. The extensor digitorum tendon runs along the dorsum of the proximal phalanx, while the flexor digitorum profundus and superficialis tendons run along the volar aspect.

Proximal phalanx fractures are often unstable due to the forces exerted on the fracture fragments by both the intrinsic and extrinsic hand muscles via their respective tendons, which typically cause apex volar angulation (figure 3) [1]. The intrinsic tendons are relaxed when the metacarpal-phalangeal (MCP) joint is flexed, while the extrinsic extensor tendons are relaxed when the wrist is extended. Thus, MCP flexion with wrist extension is often the position of choice for fracture reduction and alignment during the healing process.

MECHANISM OF INJURY — Fractures of the proximal phalanx are caused by a direct blow, rotary force, or hyperextension of the phalanx [2]. A direct blow to the hand is the most common cause of injury and produces a transverse or comminuted fracture. Such fractures are often unstable because of the forces exerted by various muscles. (See 'Clinical anatomy' above.)

Twisting injuries result in oblique or spiral fractures. Intra-articular fractures of the proximal phalanx can occur with metacarpal-phalangeal (MCP) or proximal interphalangeal (PIP) joint dislocations. Avulsion fractures can occur with tendon and collateral ligament injuries. Hyperextension combined with ulnar or radial deviation is the mechanism for collateral ligament avulsion fractures, but such injuries are relatively uncommon in fingers other than the thumb. Condylar fractures occur from a longitudinal force exerted along the axis of the phalanx (figure 4). Thumb injuries are reviewed separately. (See "Evaluation of the patient with thumb pain".)

CLINICAL PRESENTATION AND PHYSICAL EXAMINATION — Patients with proximal phalanx fractures complain of pain at the phalanx. Often swelling and bruising are present after a direct blow to the dorsum of the hand or a twisting injury. Motion at the distal or proximal interphalangeal joints is often limited.

The injured hand should be examined for deformity and gently palpated for focal tenderness and crepitus. Some degree of angulation, shortening, or rotation may exist. Proximal phalanx fractures are often unstable due to their apex volar angulation and the forces exerted on individual fragments (figure 3) [3]. Examine the phalanx with the fingers in full extension as well as in flexion. Although pain may limit this assessment, the finger should be carefully examined for weakness of the extensor and flexor tendons, which may reflect tendon injury. Stress testing of the collateral ligaments should be performed as well. Comparison with the uninjured hand can be helpful.

Evaluation for malrotation is performed by flexing the metacarpal-phalangeal (MCP) and proximal interphalangeal (PIP) joints (picture 1). Normally, all fingers are directed toward the radius and there should be no overlap or rotation (picture 2 and picture 3). Malrotation may also be evaluated by positioning the fingers with the MCP joints in flexion and the PIP and distal interphalangeal (DIP) joints in extension (picture 4).

The neurovascular status of fingers is evaluated using two-point discrimination and capillary refill time. Although values for both these tests increase with age and certain disease states (eg, diabetes), normal two-point discrimination is approximately 4 to 5 mm, while normal capillary refill is generally less than 2 seconds [4]. (See "Finger and thumb anatomy".)

PROXIMAL THUMB INJURY — Fractures of the base of the proximal phalanx most frequently involve the thumb (but seldom the other fingers) and generally occur from a hyperextension injury combined with either ulnar deviation (more common) or radial deviation, resulting in a collateral ligament avulsion fracture. These injuries are reviewed in detail separately. (See "Evaluation of the patient with thumb pain", section on 'Deformity at the MCP joint' and "Ulnar collateral ligament injury (gamekeeper's or skier's thumb)".)

DIAGNOSTIC IMAGING — Posterior-anterior (PA), lateral, and oblique radiographs of the injured finger are necessary for evaluation of phalangeal fractures (image 1 and figure 5). The lateral view of the injured phalanx should be free from overlap with other fingers if at all possible. Overlap creates difficulty in evaluating displacement or angulation of fractures, especially at the base of the proximal phalanx (image 2). Radiographs should be carefully examined for rotation, shortening, and angulation.

Fractures at the base of the proximal phalanx commonly occur in a transverse orientation with an apex volar angulation that is best seen on the lateral view (image 3 and image 4). Avulsion fractures can occur at the base of the proximal phalanx and may involve the volar plate of the metacarpal-phalangeal (MCP) joint or collateral ligaments. Shaft fractures of the proximal phalanx are often oblique or spiral (image 5). They may be stable if the periosteal sleeve remains intact (image 6). Distal fractures of the proximal phalanx are less common, but often are unstable due the location of the flexor and extensor tendons (image 7). Comminuted fractures may occur and are unstable (image 8).

Condyle fractures are classified into three types: type I (nondisplaced and stable), type II (unstable), and type III (comminuted or bicondylar) [5]. Condylar fractures at the head of the proximal phalanx generally involve one condyle and are often unstable (figure 4 and image 9 and image 10).

DIAGNOSIS — Fractures of the proximal phalanx are diagnosed by plain radiograph. Clinicians should suspect such injuries in patients who have sustained direct or indirect trauma to the finger or hand and show signs of pain, swelling, focal tenderness, and possibly deformity at the base of the finger.

DIFFERENTIAL DIAGNOSIS — Diagnosis of a metatarsal shaft fracture is straightforward using plain radiographs. Thus, issues related to the differential diagnosis have to do primarily with other possible associated injuries sustained from the inciting trauma, including ligament and tendon injuries, bone contusions, nerve injuries, and other soft-tissue damage.

INDICATIONS FOR REFERRAL — A hand or orthopedic surgeon should be consulted immediately for any open fracture and any fracture associated with a tendon, nerve, or vascular injury.

All intra-articular, unstable, rotated, shortened, comminuted, or significantly angulated fractures should be referred to an orthopedic or hand surgeon. The majority of spiral and oblique fractures (picture 5), condylar fractures (image 9), neck fractures, and large avulsion fractures are unstable and therefore warrant referral.

Referral is necessary whenever a fracture cannot be reduced or the reduction cannot be maintained. No degree of rotation is acceptable following a reduction [6]. Less than 10 degrees of angulation and less than 2 mm of shortening may be tolerated [7].

INITIAL TREATMENT — Proximal phalanx fractures that require orthopedic referral should be placed in a radial or ulnar gutter splint, depending upon the finger involved, with the metacarpal-phalangeal (MCP) joint in 70 to 90 degrees of flexion and the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints in slight flexion (picture 6).

Nondisplaced stable fractures — A transverse, oblique, or avulsion fracture that is nondisplaced, not angulated, and appears stable can be treated initially by splinting and buddy taping the injured finger to an adjacent finger (picture 7). If the ring finger is involved, it should be buddy taped to the little finger. If there is significant pain or possible instability, an ulnar or radial gutter or Burkhalter splint can be used [2,8]. The MCP joint should be flexed to 70 to 90 degrees and the PIP and DIP joints left in full extension. The Burkhalter splint is described in the following section.

Displaced or angulated fractures — Angulated transverse fractures generally present with apex-volar angulation. This angulation results from the pull of the intrinsic hand muscles on the proximal fragment into flexion and a concomitant extension force from the extensor insertion acting on the distal fragment via the middle phalanx [7]. Closed reduction of such fractures can produce satisfactory alignment. A digital block provides adequate anesthesia for the procedure.

To perform a closed reduction, flex the MCP and PIP joints to 90 degrees. Flexion of the MCP joint to 90 degrees reduces the volar force exerted upon the proximal fragment by relaxing the interosseous muscles and tightening the stabilizing collateral ligaments. Flexion of the PIP joint allows for reduction of the distal fragment.

After positioning the joints, use a three-point reduction technique with gentle traction to reduce the proximal fragment dorsally and the distal fragment volarly. The fragment ends should meet at the fracture line.

Once the reduction is achieved, the MCP joint remains in 70 to 90 degrees of flexion, with the PIP joint in extension or slight flexion [2,8]. The reduction is held in position by a radial or ulnar gutter splint (picture 6), with the fractured finger buddy taped to an adjacent finger.

A Burkhalter splint can be used in place of a gutter splint if there is concern about joint stiffness arising from immobilization of the PIP joint. As an example, such concern may arise when treating older adults or patients whose livelihood depends upon fine motor movement. In the Burkhalter, the wrist is placed in 30 degrees of extension with the MCP in 90 degrees of flexion (picture 8). A dorsal splint is placed from the forearm to the PIP joint. A volar splint is placed from the forearm to the proximal palmar crease. This provides immobilization of the MCP joint but allows PIP and DIP motion.

Evidence supporting use of the Burkhalter splint is scant. In one observational study involving 45 patients with 48 displaced proximal phalanx fractures, only four patients treated with a dynamic splint similar to the Burkhalter showed signs of restricted joint motion [9].

DEFINITIVE TREATMENT AND FOLLOW-UP

Nondisplaced stable fractures — Nondisplaced fractures are reevaluated one week following the initial injury. Reassessment includes a careful physical and radiographic examination looking for evidence of displacement, shortening, angulation, or rotation. Once the fracture is stable, the splint can be removed and buddy taping to an adjacent finger used in its place to provide stability. To help prevent joint stiffness, splints should generally not be continued for longer than three weeks [10]. Evaluations are repeated every one to two weeks until clinical healing occurs, generally within four to six weeks. Clinical healing is indicated by the absence of pain with palpation or motion.

Displaced or angulated fractures treated with reduction — Displaced or angulated fractures that are successfully reduced should be reevaluated one week following reduction. Reassessment is especially important for oblique or angulated fractures managed non-operatively as loss of reduction is common. Reassessment includes a careful physical and radiographic examination looking for evidence of displacement, shortening, angulation, or rotation. Evaluations are repeated every one to two weeks while treatment continues with a gutter or Burkhalter splint. Clinical healing, indicated by the absence of pain with palpation or motion, generally occurs within three to four weeks [2]. Splinting is discontinued at this time and protected mobilization instituted to avoid tendon contractures. Buddy taping is used to protect the finger for several additional weeks. Full radiographic healing may require up to six months.

According to several small, primarily observational studies, dynamic splints are an effective tool for treating stable, extra-articular proximal phalanx fractures, and reduce the number of patients with proximal interphalangeal (PIP) and distal interphalangeal (DIP) joint stiffness [11-14]. Lucerne casts and metacarpal-phalangeal (MCP) block splints (figure 6) immobilize the MCP joint while allowing normal motion of the PIP and DIP joints, and often the wrist [15]. Dynamic splinting is most effective for treating extra-articular fractures at the base of the proximal phalanx. Closed reduction may be necessary prior to splinting to minimize displacement or angulation.

Dynamic splinting has not been studied in fractures involving the joint (ie, intra-articular), middle or distal shaft, or rotation, or associated with a tendon injury, and cannot yet be recommended for such injuries. Patient compliance with the splint and physical therapy is mandatory for a good outcome. Clinicians with access to occupational therapists may benefit from their expertise and choose to have them supervise dynamic splint use and physical therapy.

For fractures amenable to dynamic splinting, once reduction is completed, the author suggests placing a MCP block splint with the MCP joint flexed as close to 90 degrees as can be tolerated. Repeat radiographs are obtained at one week and if necessary the hand is re-splinted to maintain a full 90 degrees of MCP flexion. The patient is encouraged to perform flexion and extension exercises of the PIP and DIP joints while in the dynamic splint, which should be done using all fingers simultaneously in order to avoid rotational deformities.

For patients treated in a dynamic splint, we perform a clinical reassessment and obtain repeat radiographs at two and four weeks. Physical therapy is recommended for patients with PIP extension lag or severely limited motion. Once callus is present and the patient is pain free, the dynamic splint is removed. Physical or occupational therapy may be continued as necessary to help the patient regain motion and strength. Patients may return to work or sport once bone healing is stable and motion and strength have been regained, which on average requires 6 to 12 weeks.

The use of dynamic splints is supported by several studies. In a 10-year observational study of 103 stable proximal phalanx fractures in 97 patients treated in MCP block splints, 75 percent of patients had excellent or good results at one year and no patient had a delayed union or required surgery [11]. Other observational studies of dynamic splinting report similar results [12]. In a randomized trial of 66 consecutive patients with 75 extra-articular proximal phalanx fractures, patients treated in a Lucerne cast allowing free wrist motion had no differences in outcome other than improved wrist motion at the time of cast removal compared to patients treated in a traditional cast [14].

RECOMMENDATIONS FOR RETURN TO WORK OR SPORT — Patients with nondisplaced proximal phalanx fractures may return to work and sport once pain is controlled provided that protective buddy taping is used. Displaced or angulated fractures require three to four weeks of protective splinting, during which time high risk activities should be avoided. Patients may then return to work and sport, but buddy taping should be used for an additional three to four weeks.

COMPLICATIONS — Fractures of the proximal phalanx can lead to disabling complications. Significant angulation, shortening, or rotation of the fracture can lead to finger malrotation (picture 2) and abnormal hand mechanics. A "pseudo-claw" deformity with loss of posterior interphalangeal (PIP) extension and hyperextension of the metacarpal-phalangeal (MCP) joint can develop with persistent volar angulation of the fracture [8]. Tendon contractures and loss of joint motion can occur with prolonged or inappropriate immobilization, especially at the PIP joint. Joint stiffness and loss of motion is more common in older adult patients and fractures associated with underlying tendon injuries [2]. Proximal phalanx fractures may result in mild joint stiffness after treatment. Rehabilitation can help to improve function following such injuries. Nonunion occurs in less than one percent of fractures [16].

ADDITIONAL INFORMATION — Several UpToDate topics provide additional information about fractures, including the physiology of fracture healing, how to describe radiographs of fractures to consultants, acute and definitive fracture care (including how to make a cast), and the complications associated with fractures. These topics can be accessed using the links below:

●(See "General principles of fracture management: Bone healing and fracture description".)

●(See "General principles of fracture management: Fracture patterns and description in children".)

●(See "General principles of definitive fracture management".)

●(See "General principles of acute fracture management".)

●(See "General principles of fracture management: Early and late complications".)

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: Fractures of the skull, face, and upper extremity in adults" and "Society guideline links: Acute pain management".)

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 5^th to 6^th 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 10^th to 12^th 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: Finger fracture (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Mechanism and clinical presentation – Fractures of the proximal phalanx are caused by a direct blow, rotary force, or hyperextension of the phalanx. The injured hand should be examined for deformity, neurovascular compromise, focal tenderness, and tendon dysfunction. Some degree of angulation, shortening, or rotation may exist. (See 'Mechanism of injury' above and 'Clinical presentation and physical examination' above.)

●Diagnostic imaging and high risk for deformity – Proximal phalanx fractures are often unstable and at high risk for angulation, rotation, and shortening. Radiographs should be carefully examined for such deformities. (See 'Diagnostic imaging' above.)

●Indications for surgical referral – A hand or orthopedic surgeon should be consulted immediately for any open fracture and any fracture associated with a tendon or nerve injury. All intra-articular, unstable, rotated, shortened, or significantly angulated fractures should be referred. (See 'Indications for referral' above.)

●Management – Treatment is determined by the nature of the fracture:

•Nondisplaced, stable proximal phalanx fractures are treated with immobilization using a splint and buddy taping or a splint alone.

•Angulated transverse fractures generally present with apex-volar angulation. Closed reduction of such fractures can produce satisfactory alignment.

•Displaced proximal phalanx fractures are generally treated with a gutter or Burkhalter splint until early healing has occurred (typically three to four weeks post-injury), and are then treated with buddy taping for an additional three to four weeks.

•In some cases, dynamic splinting may be used to treat stable, extra-articular proximal phalanx fractures, and may reduce distal interphalangeal (DIP) and proximal interphalangeal (PIP) joint stiffness. (See 'Initial treatment' above and 'Definitive treatment and follow-up' above.)