Malunion of Hand Fracture Treatment & Management

Indications for surgical treatment of hand malunion include the following:

• Pain
• Loss of function
• Cosmetic deformity
• Loss of motion in the neighboring joint
• Bony exostosis causing skin irritation and posing a threat of tendon attrition

When treating hand malunions, one must remember that the potential risks of surgery (eg, tendon adhesions and joint stiffness) may outweigh any anticipated advantage.

The absolute contraindication for surgery is local infection. Relative contraindications include a functionless limb, poor bone quality, and poor general medical condition.

In the future, expanded use of bioabsorbable implants made of polyglycolic acid or poly-L-lactic acid may have advantages over the traditionally used pins, screws, and plates. These bioabsorbable plates will help avoid the need for second procedures to remove implants, which are the main causes of loss of function from iatrogenic causes. Further development of low-profile implants with high tensile strength will allow adequate mobility during postoperative rehabilitation and thereby help prevent stiffness.

The hand is a highly complex structure that requires integrated function of extrinsic and intrinsic motor units across a complex and limited bony and articular framework. The hand also functions as a sensory organ and an organ of communication. All these factors should be considered before reconstruction is undertaken.

Goals of surgical treatment

The goals of treatment are to restore disordered function and, occasionally, to correct cosmetic deformity. Accordingly, the malunion should be carefully studied with an eye to understanding the original deforming forces. Important principles in the management of malunions include the following:

• Rotational deformities are most disabling yet frequently not appreciated; a 10° rotational malunion results in a 2-cm overlap at the fingertip; alignment should always be checked with the fingers flexed in the palm
• An appropriate form of osteotomy and subsequent fixation must be tailored to each individual deformity; familiarity with osteotomy techniques and alternative forms of fixation affords flexibility in treating deformities
• The soft tissues must be inspected carefully for scarring, adhesions, and contractures; careful protection of delicate structures by judicious tenolysis and arthrolysis may be needed at the time of osteotomy
• Appropriate, functional postoperative rehabilitation is a must for good results; otherwise, even the best surgery produces suboptimal results

A carefully planned osteotomy is necessary and must be executed with the least possible further damage to soft tissues. Techniques of osteotomy must be tailored to the biomechanical requirements for proper realignment of the malunited fracture.

Seo et al described an osteotomy technique for correcting malunion of the proximal phalanx that is minimally invasive and is performed under local anesthesia. ^[10] They reported that this technique has the advantage of permitting active flexion and extension, which leads to more accurate reduction and earlier recovery.

Preparation for surgery

Adequate surgical planning requires adequate preoperative assessment. The patient's neurovascular status should be assessed before any intervention is performed. Intraoperative fluoroscopy or radiography should be used to ensure that adequate fixation is achieved before the patient leaves the operating room. Joint motion should be assessed after fixation so that postoperative expectations can be established.

Malunion of phalangeal fractures

Clinically significant malrotation results in functional impairment and usually necessitates osteotomy through the phalanx or the metacarpal. (See the images below.)

Phalangeal osteotomy corrects the malunion at its site of origin, allows simultaneous correction of angular deformities, and permits concomitant soft-tissue procedures such as tenolysis or capsulotomy. Phalangeal osteotomies can be either step-cut ^[11] or transverse, which are performed with a power saw. Step-cut osteotomies are fixed with either small AO (Arbeitsgemeinschaft für Osteosynthesefragen [Association for the Study of Osteosynthesis]) screws or Kirschner wires (K-wires); transverse osteotomies can be held with a plate or with K-wires.

Metacarpal-base osteotomies ^[12] for malrotation correction can achieve up to 18-19° of correction in the index, long, and ring fingers and up to 20-30° in the small fingers.

Volar angulation of 25-35° results in fixed flexion deformity of the proximal interphalangeal (PIP) joint. This requires correction by means of either closing- or opening-wedge osteotomy and fixation with K-pins. The opening wedge requires a bone graft to fill the gap, whereas the closing wedge may result in shortening of the finger.

Lateral angulation of phalangeal fractures is corrected in the same manner as volar angulation—that is, by performing osteotomies with a power saw.

Shortening due to a comminuted fracture that is allowed to heal in a collapsed fashion or that occurs after a long spiral fracture can be corrected with an appropriately fashioned intercalary graft insertion. When a spiral fracture of the phalanx heals in a shortened position with a distal spike on the proximal fragment, blocking flexion of the digit, careful removal of the spike may be all that is required.

Unreduced condylar fractures extending into the joint require corrective osteotomy, arthrodesis, or arthroplasty.

Malunion of metacarpal fractures

Dorsal angulation usually occurs in the second or third metacarpal and is bothersome, both cosmetically and functionally, in that it weakens the grip of the hand (see the images below). Correction is achieved with closing- or opening-wedge osteotomies or fixation with K-wires or AO plates.

The closed wedge is preferred over the open wedge for two reasons. First, healing of only one surface is required, unlike the open wedge, in which healing of two surfaces is required. Second, the intrinsics can accommodate some shortening with a closed wedge, whereas with an open wedge, lengthening of the bone occurs. Such lengthening may aggravate the intrinsic tightness, especially when posttraumatic intrinsic muscle contracture has occurred.

Rotational malunion results from overlapping of the affected finger over the adjacent finger. Cosmetic deformity is often marked, and grip is impaired. Correction is achieved through a metacarpal-base osteotomy. ^[12] During the operation, a longitudinal mark is made on the metaphysis with an osteotome prior to the osteotomy. Then, the osteotomy is performed with a power saw perpendicular to the mark. The rotation is corrected and fixed with several K-wires or AO plates.

Intra-articular metacarpal malunions are difficult to correct with osteotomies. However, correction can be achieved by maintaining reduction with screws and plates or with screws and cancellous bone grafts. ^[3]  Treatment with K-wires and a costal cartilage graft has been reported. ^[13]

Malunion in carpal bones

The scaphoid is the usual site for carpal malunion. ^[14] Malunion of other carpal bones is rare. Malunion of the scaphoid is best prevented. If malunion of the scaphoid is detected soon after union, corrective osteotomy can be considered. Late malunion of the scaphoid is best managed symptomatically. Finally, scaphoid cheilectomy or radial styloidectomy can be considered if symptoms persist.

Optimal site for osteotomy

Whether osteotomy for malunion of metacarpals and phalanges in the hand should be done at the original fracture site or at a separate site is a matter of debate. Correction at the fracture site is generally preferred, in that it addresses the issue at the site of pathology (ie, malunion) and thus can correct the combined deformity (translation, rotation, and angulation). Furthermore, it enables the surgeon to perform tenolysis and capsulolysis at the same time. It especially avoids the zigzag deformity produced by the osteotomy away from the fracture site.

A corrective osteotomy performed at the level of the fracture site is called a focal osteotomy, whereas one performed away from the original fracture site is called an extrafocal osteotomy.

Extrafocal osteotomies do not restore the normal anatomy. However, there are instances where this may be preferred, as in the case of a malunion resulting from a complex or compound fracture that can be treated by a single osteotomy rather than a focal osteotomy. The latter may have to be complex, and the metacarpal or the phalanx may not lend itself to such a complex procedure. Extrafocal osteotomy is also preferred in articular malunions when there is enough joint space or if the articular fragment is too small to be interfered with.

Opening-wedge vs closing-wedge osteotomy

Basically, an osteotomy can be a closing-wedge or an opening-wedge procedure. A closing-wedge osteotomy has the advantage of inherent stability with no additional bone graft; however, it shortens the digit. An opening-wedge procedure may need a structural bone graft, but this is not always the case, as when secure fixation is obtained with a plate and screw, where cancellous bone graft can be used as supplementation.

Karthik et al reported good long-term results from the use of closing-wedge osteotomy with temporary intramedullary K-wire and plate fixation to treat 14 symptomatic malunited metacarpal fractures in 12 patients. ^[15]  At a mean follow-up of 46 months (range, 12-78), patients had signnificantly better Disabilities of the Arm, Shoulder, and Hand (DASH) scores, and all of them had a score of excellent according to the Büchler criteria and, by final follow-up, were able to resume their preinjury work and sports activities.

Securing of osteotomy

As with any other fracture, different options are available, including plaster immobilization, K-wire fixation, plate-and-screw fixation, and external fixator application. An osteotomy can be left alone only if there is inherent stability at the osteotomy site, which can occur with step-cut osteotomies. Basal osteotomies can be held with K-wires. However, plate-and-screw fixation is preferred for rigid fixation and immediate postoperative mobilization to prevent stiffness and adhesions and thereby improve function.

Timing of osteotomy

The timing of operative intervention is vital, especially in malaligned fractures proceeding to established malunion. If the fracture malalignment is addressed surgically within 10 weeks, then the fracture site can be exposed, the callus can be removed to recreate the original fracture, and the fracture can be managed with appropriate fixation.

When functional loss is predicted from the amount of malalignment at the time of evaluation, there is little value in waiting to perform the correction. However, in cases with milder deformities, it is better to wait to do a corrective osteotomy until the degree of functional loss can be estimated.

Most surgery in the hand is undertaken to promote function. Early mobilization is essential to ensure a good outcome. Delaying motion beyond 3 weeks leads to arthrofibrosis and a poor functional outcome. Optimal surgical treatment should allow adequate postoperative motion, and to achieve a good outcome, patients should be encouraged to move their fingers daily.