Fractures and Dislocations of the Hand

Regional Anatomy

The double saddle-joint design of the thumb CMC joint allows for a wide range of flexion-extension, abduction-adduction, and pronosupination of the thumb. Four main ligaments stabilize this articulation during pinch and grasp. These include the anterior and posterior oblique ligaments, the dorsal-radial ligament, and the intermetacarpal ligament ( Fig. 40.3 ). The volar oblique ligament is stout originating from the trapezium and inserting onto the volar beak of the thumb metacarpal. It resists dorsoradial subluxation. The thin dorsal capsule is reinforced by the aponeurosis of the abductor pollicis longus.

Examination

AP Robert, lateral, and oblique radiographs of the thumb are standard. Traction radiographs are beneficial for assessing the effect of ligamentotaxis on reduction, but are often reserved for the intraoperative setting.

Indications

Surgical indications include sagittal plane angulation greater than 30 degrees, joint subluxation, and articular incongruity (e.g., gap and depression) greater than 2 mm.

Surgical Exposures and Fixation Techniques

For epibasilar and proximal shaft metadiaphyseal fractures, closed reduction and percutaneous Kirschner wire (K-wire) fixation is attempted ( Fig. 40.4 ). Given the short metaphyseal segment, transarticular fixation across the CMC joint with fixation into the trapezium is performed. A minimum of two K-wires (0.054 or 0.045 inch) are used. The K-wires are removed at 4 weeks postoperatively. Cast immobilization is used while the K-wires are in place.

When acceptable reduction cannot be achieved in a closed fashion or in combined injuries, open reduction through a dorsal approach is performed. Following elevation of skin flaps and protection of regional branches of the radial sensory nerve, the interval between the extensor pollicis brevis (EPB) and longus is developed ( Fig. 40.5 ). Meticulous subperiosteal dissection along the fracture may allow the periosteum to be closed over the plate and helps minimize the potential for extensor tendon adhesions. Following fracture reduction, provisional K-wire fixation placed in the radial midaxial plane may be performed before plate application if the reduction is unstable. Given the short metaphyseal segment, a fixed-angle (i.e., condylar blade plate or locking plate) construct is preferred. In this area, 2- and 2.4-mm T- or Y-plates are often used ( Fig. 40.6 ; see Video 40.1 ). Localization of the trapeziometacarpal joint can be achieved by placing a K-wire through one of the locking sleeves before screw fixation begins to avoid intraarticular screw placement. If the epibasilar fracture is oblique, a nonlocking bicortical interfragmentary screw can be placed perpendicular to the obliquity. For transverse fractures, compression technique is followed. Bridge plating is used for comminuted and axially unstable fracture patterns.

Following open reduction and internal fixation (ORIF), early functional rehabilitation is initiated within the first postoperative week. The patient is transitioned to a short or long opponens splint and thenar cone and tendon gliding exercises are begun. Pinch strengthening is initiated between 4 and 6 weeks postoperatively when there is evidence of clinical and early radiographic union.

For partial and complete articular fractures at the base of the thumb metacarpal, the volar-ulnar articular fragment is variably sized, but remains reduced by the stout volar-oblique ligament to the trapezium. Intraarticular fractures may consist of a small oblique fragment or a larger articular shear fracture. Meticulous assessment of the articular surface is needed after reduction to assess for any central articular impaction. Often, this is best assessed after an attempted closed reduction using a combination of longitudinal traction, direct reduction at the apex of the dorsoradial deformity, abduction, and pronation of the shaft under fluoroscopy. Articular impaction typically does not correct with closed reduction and requires formal open reduction, as described later, to elevate the central impaction and restore joint congruity.

Congruent joint and fracture reduction is the goal regardless of operative technique selected. When the metacarpal base subluxation can be reduced and articular congruency obtained with closed reduction, percutaneous K-wire fixation is performed using 0.054- and/or 0.045-inch wires. K-wire entry begins along the dorsoradial border of the thumb metacarpal. One of several configurations is acceptable. The K-wire does not need to cross the fracture site. Beginning in the dorsoradial aspect of the shaft will often allow one to advance the wire across the dorsal quadrant of the articular surface of the metacarpal to obtain transarticular fixation within the trapezium ( Fig. 40.7 ). Alternatively, the wire can be advanced into the base of the index metacarpal. Two to three diverging K-wires are used to maximize stability of the construct. AP Roberts and lateral views confirm reduction and K-wire positions. Wires are routinely cut and bent outside of the skin. The K-wires are removed at 4 to 6 weeks postoperatively. Cast immobilization is used while the K-wires are in place.

When acceptable reduction cannot be achieved, or the volar-ulnar fragment is larger than 20% to 30% of the articular surface, ORIF is performed ( Fig. 40.8 ). A palmoradial Wagner incision is used, which extends from the distal wrist flexion crease overlying the flexor carpi radialis (FCR) and extends distally along the shaft of the metacarpal at the junction of the glabrous and nonglabrous skin. Skin flaps are elevated and cutaneous branches of the palmar cutaneous, radial sensory, and lateral antebrachial cutaneous nerves are carefully mobilized and protected. The thenar intrinsic musculature is elevated extraperiosteally from the shaft segment. The insertion of the abductor pollicis longus (APL) is identified and protected. An arthrotomy is performed. Soft tissue attachments to the fracture are preserved.

Supination of the metacarpal shaft greatly facilitates fracture site exposure. For simple sagittal plane fractures, the shaft can be reduced with traction, abduction, and pronation and the articular fragment controlled with a dental pick and secured with a fine reduction forceps. A dorsal skin flap is elevated to facilitate provisional K-wire placement and modular lag screw insertion dorsal to the APL. They are typically placed from dorsal-radial to volar-ulnar to secure fixation of the articular fragment. Modular hand screw size and trajectory are selected based on the size of the articular fragment and the obliquity of the fracture line. Modular hand screws, 1.1 to 2.4 mm, should routinely be available. K-wires of corresponding diameter to the screw core diameter are selected so that the provisional K-wires can be sequentially exchanged for bicortical screws. When the fragment is smaller, a single screw and K-wire or an additional 1.3- or 1.1-mm screw may be used. We favor two screws, even if this requires placement of a 1.3- or 1.1-mm screw.

Alternatively, an “inside-out” technique may be used. The shaft segment may be first hypersupinated to expose the cancellous surface of metacarpal fracture line and then drilled from volar to dorsal from “inside” the fracture site. This ensures that after fracture reduction and bicortical drilling from dorsal to volar the screw trajectory obtains maximal purchase in the articular fragment. Intraoperative fluoroscopy is essential in assessing joint reduction, articular congruency, and subchondral screw position.

Central impaction requires elevation using the trapezium as a template, and supplemental cancellous bone grafting may be needed in select cases. When the articular fracture line is vertical, shear forces should be neutralized before screw fixation. When there is an associated trapezial body fracture, reduction and fixation of the trapezium are performed before the metacarpal articular fracture.

Complete articular Rolando-type fractures are often the result of axial loading of the joint surface. Preoperative CT scan may help elucidate the plane of the intraarticular fracture and help in the selection of operative exposure. At times, these fractures may reduce with traction. Meticulous K-wire placement allows restoration of the joint surface. Additional K-wires are then used to secure the shaft to the articular segments.

Coronal and sagittal plane fracture lines affect the selection of surgical exposure. When the main fracture line is in the coronal plane, a dorsal exposure is used; when the articular split is in the sagittal plane, a palmoradial exposure is selected. Stepwise reduction of the articular surface and provisional K-wire fixation are performed. Articular fragments may be captured through independent modular hand lag screws or with screws placed through the plate. A fixed-angle construct is preferred and 2- to 2.4-mm condylar or locking plates are used. The transverse portions of the plate allow for stabilization of the basilar fragments. When the fracture line is in the coronal plane, eccentric placement of cortical screws in the T or Y portion of the locking plate creates interfragmentary compression. Plate contouring along the shaft is necessary to prevent residual deformity. Provisional plate fixation proximally and distally is helpful to avoid shaft malrotation. Care is taken to avoid convergence of the screws along the volar cortex and articular violation.

Following open reduction and stable internal fixation, early functional rehabilitation is begun within the first postoperative week. The patient is transitioned to a short opponens splint and thenar cone and tendon gliding exercises are begun. Pinch strengthening is initiated between 4 and 6 weeks postoperatively when there is evidence of clinical and early radiographic union.

Highly comminuted articular fractures may require limited ORIF of the articular segment, bone grafting of the metaphyseal void, and supplemental bridging external fixation to maintain distraction across the trapeziometacarpal joint. Various external fixation constructs may be used. Terminally threaded 1.1- to 1.25-mm K-wires may be placed in the thumb and index metacarpal to create a stable quadrangular construct that also maintains the first web space to minimize web space contracture. Alternatively, K-wires may be placed in the thumb metacarpal combined with a trapezial wire to directly distract the trapeziometacarpal joint. The frame is removed between 4 and 6 weeks postoperatively.

Outcomes

Early literature favored nonoperative treatment of these articular fractures, and a single study reported little evidence of symptomatic arthrosis after nonoperative treatment of partial articular fractures at the base of the thumb metacarpal. Contemporary series demonstrated that clinical and radiographic outcomes are optimized when subluxation is corrected and there is less than 1 mm of articular gap after reduction and stabilization. Other clinical series confirmed that residual articular incongruity yields a higher incidence of symptomatic posttraumatic arthrosis. Biomechanical evidence supports the rationale for articular reduction as simulated Bennett malunion with a 2-mm stepoff created abnormal joint contact forces dorsoradially.

Sequelae

In the majority of cases, functional thenar motion and pinch strength are recovered. Residual stiffness rarely requires additional treatment. In some cases, extensor tenolysis with concomitant removal of hardware may be required and is performed 4 to 6 months postoperatively when the soft tissue envelope is supple and full osseous union is confirmed. The risk of arthrosis is greater after complete articular fractures in this area. In the setting of a high-energy mechanism of injury and articular fracture-subluxation/dislocation, periarticular heterotopic ossification may be seen but no cases of bridging ankylosis have been reported ( Fig. 40.9 ).

If intraarticular fractures are suboptimally reduced, the resulting articular malunion, especially if associated with persistent subluxation, may progress to trapeziometacarpal arthrosis. Corrective closing wedge or intraarticular osteotomy is indicated for persistent joint subluxation and instability if recognized before development of arthrosis. In these cases, preoperative CT scan may be helpful to define the fracture plane and to aid in osteotomy planning ( Fig. 40.10 ). Once degenerative arthrosis has developed, salvage options include arthroplasty and arthrodesis. Chronic pain and instability treated with arthrodesis tends to be less well tolerated than arthrodesis at the fourth or fifth CMC joints. Nonunion at the base of the thumb metacarpal is rare.

Future Directions

Some centers reported the use of small joint arthroscopy to aid in the reduction and fixation of thumb MCP and CMC articular fractures and collateral ligament avulsion fractures. Culp and Johnson described arthroscopically assisted reduction using a 1.9-mm arthroscope and percutaneous fixation of Bennett fractures. It remains unclear whether arthroscopically assisted reduction and stabilization offer superior clinical or radiographic outcomes, and in our practices, use of arthroscopy in the treatment of these injuries has had a limited role.

Carpometacarpal Joint

Surgical Exposures and Technique

Frank dorsal dislocations are initially managed with closed reduction. Stability is assessed. If a closed reduction is congruous and stable, closed treatment with thumb spica casting is initiated together with close serial radiographic follow-up.

There is no consensus for optimal treatment of persistent or recurrent clinical or radiographic instability. Options include closed reduction and percutaneous transarticular trapeziometacarpal K-wire fixation, Eaton-Littler anterior oblique ligament reconstruction, and open reduction and repair of the dorsoradial ligament complex comprised of the dorsoradial and posterior oblique ligaments. Combined reconstruction of the volar oblique ligament and dorsal radial complex may be optimal. Limited open approaches have been described as well.

Anterior oblique ligament reconstruction is performed using the volar-radial Wagner exposure and volar CMC capsulotomy to inspect the articular surfaces, followed by utilization of the FCR to reconstruct the anterior oblique and dorsal-radial ligamentous complex. The distally based autograft is passed through a volar-to-dorsal subchondral intraosseous channel, secured to the dorsal periosteum, passed deep to the APL and secured to the dorsal capsule, weaved through the ulnar one-half of the FCR, and then secured back to the radial capsule ( Fig. 40.11 ). There is no consensus whether the reconstruction requires supplemental transarticular pinning. Postoperative cast immobilization is used for approximately 4 to 6 weeks, and then patients are transitioned to a custom Orthoplast long opponens splint, which is removed for range-of-motion exercises. Thenar cone strengthening is initiated at 2 months postoperatively followed by pinch and grasp strengthening. Associated trapezial body fractures are treated with ORIF ( Fig. 40.12 ).

Combined repairs of the dorsoradial ligamentous complex and anterior oblique ligament supplemented with transarticular K-wire fixation for 6 weeks with the CMC in the “screw-home-torque opposition” position is advocated by Edmunds. Cadaveric biomechanical studies support the importance of the dorsoradial ligamentous complex in CMC stability and this surgical approach. When the dorsal-radial complex is irreparable, Eaton-Littler reconstruction is performed.

Ozer described a new surgical technique performed through a dorsal approach using half of the extensor carpi radialis brevis (ECRB) to reconstruct all four stabilizing ligaments of the trapeziometacarpal joint. Superficial branches of the radial nerve and the deep branch of the radial artery are mobilized after cauterizing the dorsal capsular perforating branches. A dorsal arthrotomy allows inspection of the articular surfaces. Following trapezial and metacarpal drill holes, a distal and radially based strip of the ECRB is sequentially passed:

• 1.

  The ECRB tendon is passed from the ulnar hole to the palmar hole at the base of the first metacarpal.

• 2.

  The tendon is passed from the palmar to dorsal direction through the trapezium tunnel after traversing the palmar aspect of the CMC joint.

• 3.

  The tendon is passed along the dorsal surface of the CMC joint, and passed from dorsal through the radial hole of the thumb metacarpal.

• 4.

  The tendon is then sutured to itself on the dorsal surface of the trapezium using #2-0 nonabsorbable suture. The authors did not include transarticular pinning in this report.

Appropriate tensioning of these described ligament reconstructions remains challenging. Reconstructions performed too tautly will limit CMC motion and may predispose to early arthrosis. Laxity in the reconstruction will result in persistent laxity and dysfunction.

Thumb Metacarpophalangeal Collateral Ligament Injuries

Examination

Injury to the collateral ligaments is caused by an acute, forceful coronal plane stress. Following acute injuries, tenderness over the collateral ligament and dorsal capsule, swelling, and ecchymosis are often present in combination with decreased motion. Chronic complaints include deformity and loss of pinch strength. The MCP joint may rest with appreciable coronal plane deviation of the proximal phalanx away from the incompetent collateral ligament and is more commonly seen after complete RCL injuries. A palpable, tender mass on the ulnar side is pathognomic of a Stener lesion, the displaced distal end of the UCL lying above the proximal edge of the adductor aponeurosis ( Fig. 40.13 ). In a prospective study of 24 consecutive patients with posttraumatic instability of the thumb MCP joint, Abrahamsson and colleagues confirmed that the presence of discrete soft tissue prominence at the level of the UCL predicted a Stener lesion in seven of eight thumbs and was an indication for surgical exploration. RCL injuries present with pain with ulnar stress on the thumb MCP joint and, when complete, are more often associated with sagittal, coronal, and rotatory instability.

Examination aims to determine whether the injury is incomplete (grade 1 or 2) or complete (grade 3). Grade 1 injury is a sprain with no joint instability. Grade 2 is an incomplete tear with asymmetric joint laxity, in which instability does not meet the criteria for a complete tear. Grade 3 injury involves complete tear with joint instability.

Criteria for diagnosis of grade 3 collateral ligament injuries vary. In a clinical study (level II evidence), Heyman and colleagues determined that the presence of valgus instability of more than 35 degrees with the joint in extension and 30 degrees of flexion was predictive of a complete UCL tear. A Stener lesion was present in 15 of 17 cases. The diagnostic characteristics of these examination findings included sensitivity, 94%; specificity, 57%; accuracy, 83%; positive predictive value, 83%; and negative predictive value, 80%. Bowers and Hurst (level III evidence) demonstrated that preoperative stress angulation greater than 30 degrees was predictive of a complete rupture of the UCL noted intraoperatively. An alternative criterion for instability is relative opening of greater than 10 to 15 degrees compared with the contralateral side with the MCP joint in extension and 30 degrees of flexion. However, in a study of 100 asymptomatic persons, a variation of greater than 10 degrees was found between their uninjured thumbs. Testing the MCP joint in extension may be more reliable as testing in flexion may yield a false-positive grade 3 diagnosis due to rotation of the metacarpal. Lack of a firm endpoint rather than degree of angulation between thumbs is most frequently used to determine the presence of complete collateral ligament ruptures. If guarding by the patient precludes an accurate stress examination, local anesthetic (i.e., intraarticular or digital block) may be used to improve the diagnostic accuracy.

A dedicated radiographic series of the thumb is performed before stress examination to assess for a collateral ligament avulsion fracture fragment. It is important to note that the location of the avulsion fracture does not always predict joint stability. Volar subluxation of the proximal phalanx is more common with complete RCL injuries than with UCL injuries.

Routine use of ultrasound and magnetic resonance imaging (MRI) in the setting of acute injuries is not recommended. Three level I studies investigating the efficacy of ultrasound in the diagnosis of complete UCL tears reported moderate mean diagnostic characteristics. No level I studies assessed the efficacy of MRI in diagnosing acute UCL injuries. Level III series reported that MRI yields superior diagnostic capabilities. Only one study directly compared ultrasonography with MRI in the evaluation of UCL injuries and found MRI to be superior with regard to sensitivity and specificity. Dedicated extremity (wrist or digit) coils are preferred as they improve diagnostic resolution.

Indications

Partial collateral ligament injuries (grade 1 or 2) may be treated nonoperatively with immobilization. Variety exists among hand surgeons with regard to type of immobilization. Options include long and short opponens splinting or casting with or without the interphalangeal (IP) joint included. Full-time immobilization is continued for approximately 4 weeks, followed by an additional 2 to 4 weeks during sport and while beginning active range-of-motion exercises. At 6 to 8 weeks, thenar cone strengthening is initiated based on resolution of tenderness along the collateral complex.

Indications for surgical repair of thumb collateral ligament tears include instability greater than 30 degrees, 15 degrees greater than the contralateral MCP joint, lack of an appreciable endpoint with stress examination in the coronal plane, palmar subluxation greater than 3 mm, or persistent pain after nonsurgical treatment. Nonoperative treatment of grade 3 UCL tears is not consistently successful. Therefore surgical repair of complete UCL tears with or without a Stener lesion is recommended. Treatment for grade 3 RCL tears is controversial, although more recent literature favors surgical fixation. Some authors recommended casting for acute complete thumb RCL tears. The rationale for nonsurgical treatment of grade 3 RCL tears is the lack of an analogous interposing abductor aponeurosis to prevent healing. However, a single case of a radially sided Stener-type lesion has been reported. Recent literature supports surgical treatment of complete RCL tears. The ulnar force vector of the EPL maintains ulnar deviation of the MCP joint after RCL tears and may allow the ligament to heal elongated. Patients with acute unstable UCL and RCL injuries may develop late symptomatic instability or possibly degenerative joint disease of the MCP joint.

Controversy exists regarding optimal treatment of collateral ligament avulsion fractures. Satisfactory results may be obtained with nonoperative treatment when the joint is stable with stress examination. When there is instability or the avulsion fragment is displaced and malrotated, surgical fixation or fragment excision and ligament advancement are recommended.

Ligament reconstruction is indicated in a patient with symptomatic, chronic collateral ligament insufficiency when the thumb MCP joint is without arthrosis. If there is arthrosis present, arthrodesis is performed. Fixed instability of a chronically subluxated MCP joint that cannot be reduced without release of the RCL is a contraindication to graft reconstruction.

Surgical Exposures and Repair Techniques

Acute Ulnar Collateral Ligament Repairs

An apex volar chevron, lazy-S, or longitudinal midaxial skin incision centered over the ulnar aspect of the MCP joint may be used. The dorsal ulnar sensory branch of the radial sensory nerve is mobilized and protected. In the subacute setting, it may be scarred along the adductor aponeurosis and require careful neurolysis. The proximal edge of the adductor aponeurosis is inspected for the presence of a Stener lesion. The adductor aponeurosis is incised 2 to 3 mm volar to the EPL and reflected volarward. The presence of a dorsal ulnar capsular tear is noted. A dorsal longitudinal arthrotomy is performed and the articular surfaces examined. Proximal, midsubstance, or distal rupture of the UCL is determined (see Fig. 40.13 ).

Suture anchor repair is most commonly performed for insertional ruptures or proximal ligamentous avulsions from the collateral recess. Other techniques, including transosseous nonabsorbable suture, bone tunnels, and buttons, have been described. Knotless repairs with PushLock anchors have recently been advocated. Biomechanical analyses have demonstrated that nonanatomic repair alters ultimate MCP motion. The origin or insertional sites are cleared of organized hemarthrosis and fibrosis. Suture anchors are placed just distal or proximal to the articular surface. Horizontal mattress sutures are passed through the ends of the ligament for repair. If the ligament is broad and stout, it may accommodate a running locking suture repair. Occasionally, a second anchor, or double-loading the anchor eyelet with an additional nonabsorbable suture allows for a double-row horizontal mattress repair. Midsubstance tears are repaired with interrupted figure-of-eight or horizontal mattress sutures using nonabsorbable braided synthetic suture. In some scenarios, primary repair of acute midsubstance rupture is not possible, and acute primary graft reconstruction may be needed. Some advocate the use of an internal synthetic brace to supplement the primary repair (or reconstruction) as a means to limit the need for postoperative immobilization. Clinical data supporting the use of an internal brace are currently limited to expert opinion.

At the completion of the repair, an absorbable suture loaded on a “UCL needle” can be placed between the distal volar portion of the repaired ligament and the volar plate to restore the critical corner of the three-dimensional ligamentous complex. The dorsal capsular tear is repaired, especially in the setting of preoperative joint subluxation. K-wire transarticular pinning is not routinely performed. Its use varies among hand surgeons and is a current topic of study among the membership of the American Society of Surgery of the Hand. Following ligament repair, the adductor aponeurosis is repaired anatomically with #4-0 nonabsorbable suture. The thumb MCP joint is typically immobilized in a thumb spica cast for 4 to 6 weeks postoperatively. Inclusion of the IP joint varies among hand surgeons. We favor exclusion of the IP joint so that the patient may begin IP motion to minimize adhesions along the EPL. A short opponens splint is worn for an additional 2 to 4 weeks in between range-of-motion exercises. Pinch strengthening is initiated at approximately 10 weeks postoperatively.

Chronic Ulnar Collateral Ligament Reconstructions

Most commonly, chronic thumb MCP UCL insufficiency is treated with a static reconstruction using free tendon graft reconstruction ( Fig. 40.14 ). Graft options include the palmaris longus, and in its absence, use of the extensor indicis proprius, strip of the ipsilateral FCR, bone-tendon grafts, and allografts. Satisfactory results have been reported by several groups. Figure-of-eight, rectangular, and triangular (apex distal or apex proximal) configurations have been described for static graft reconstructions. Bone tunnels are created using appropriately sized drill bits or a series of handheld gouges. The ends of the tendon graft are whipstitched with nonabsorbable suture and then shuttled through the transosseous tunnels using 28-gauge stainless steel wire. Multiple graft fixation options exist including transosseous nonabsorbable sutures tied over a bone bridge or button, graft ends sutured to each other over a bone bridge, aperture fixation using Bio-Tenodesis screws, and combinations of aperture fixation and suture anchors. More recently knotless reconstruction with PushLock anchors has been advocated. Transarticular pinning is usually performed in the setting of graft reconstruction. Surgeon bias dictates whether the joint is transfixed before or after graft tensioning. The rationale for transfixion before graft tensioning is that joint position is first fixed and, therefore, avoids overtightening the graft. Alternatively, tensioning can only be adjusted if performed before transfixion.

Dynamic stabilization with adductor advancement from the ulnar sesamoid to the proximal phalanx base was advocated by Neviaser and colleagues. Success with dynamic tendon transfers using the extensor indicis proprius (EIP) and EPB have also been reported.

Acute Radial Collateral Ligament Repairs

Skin incision options for RCL repair mirror those for the UCL. Superficial branches of the radial nerve must be protected to avoid postoperative neuritis or painful neuromas. A longitudinal incision is made in the abductor aponeurosis volar to the EPB, leaving a rim of aponeurosis for closure. With the abductor aponeurosis retracted volarward, a dorsal-radial arthrotomy is performed and the RCL is examined. A decision is made as to whether to repair or reconstruct the ligament.

Acute ligament avulsions from the origin or insertion are repaired to their respective osseous footprints using one of many commercially available small bone anchors. At the volar radial base of the proximal phalanx, the anchor is placed in the volar half of the lateral tubercle 3 to 5 mm distal to the articular surface, and in the metacarpal head, the anchor is placed 1 to 2 mm dorsal to the central axis of the lateral condyle. For midsubstance tears, one can attempt an end-to-end repair, but primary ligament reconstruction may be needed. If the torn ligament is attenuated or cannot be advanced due to fibrosis, then a reconstruction is performed.

The dorsal-radial capsular tear is repaired, but care is taken to not overtighten the capsular closure to minimize loss of flexion. When there is preoperative MCP joint volar subluxation, the MCP is transfixed with a 0.045-inch K-wire to protect the repair and neutralize the adductor pollicis.

A short-arm thumb spica cast is worn for 4 to 6 weeks after surgery. The thumb IP joint is left free to minimize extensor tendon adhesions and IP joint contracture. After pin removal, the patient is transitioned to a removable hand-based thumb splint for an additional 2 weeks during which thenar cone motion is initiated. Strengthening of the thenar muscles and pinch is begun at 3 months.

Chronic Radial Collateral Ligament Reconstructions

Treatment options for reconstruction of chronic radial instability include delayed primary ligament repair, abductor advancement, and free tendon grafting ( Fig. 40.15 ). Abductor advancement is similar to the adductor advancement technique described by Neviaser et al., and may be performed alone or in combination with repair or reefing of the RCL remnant and capsule. This represents dynamic reconstruction of a static restraint. Posner and Retaillaud noted that ligament reconstruction using a tendon graft was necessary in 33% of cases with chronic RCL injury versus 69% of cases with chronic UCL injury.

When graft reconstruction is needed, the RCL remnants are excised and the proximal phalangeal subluxation and pronation are corrected in preparation for the transosseous tunnels in the proximal phalanx. The transosseous tunnels are created using appropriately sized drill bits or a series of handheld gouges. Free graft options include the palmaris longus, extensor indicus proprius, and a strip of the FCR. The orientation of the graft restores support of the dorsal capsule and the proper collateral ligament. As discussed in UCL reconstruction, the graft may be tensioned before or after MCP K-wire transfixion. The graft tails may be tied together on the ulnar side or secured with suture anchors and/or Bio-Tenodesis screws. The dorsal limb of the reconstruction may limit MCP joint flexion if it is made too tight. The conjoined tendon of insertion of the APB and the radial head of the FPB can be tightened for additional stability.

Open Reduction and Internal Fixation of Collateral Ligament Avulsion Fracture

Collateral ligament avulsion fracture is not uncommon. Treatment depends on joint stability, as well as the size of the fragment. If the fragment is small (<10% to 15% of the articular surface), it may be excised, and the ligament advanced into the defect and secured with a pullout suture or anchor. If the fragment is large, it is reduced anatomically. Fixation constructs available include tension band suture or wire, K-wires, and one or more modular hand screws ( Fig. 40.16 ). Displaced Salter-Harris type III epiphyseal fractures in the skeletally immature hand require ORIF to restore physeal anatomy, ligamentous stability, and joint congruency ( Fig. 40.17 ).

Thumb Metacarpal-Phalangeal Joint Dislocations

The thumb MCP joint is similar to the MCP joints of the other fingers. However, unique articular geometry makes the MCP joint of the thumb more hingelike than multiaxial. Sesamoids lie anterior to the metacarpal head and are embedded in the volar plate. The FPB and APB muscles partially insert into the sesamoids. Collateral ligament anatomy in the thumb MCP joint is similar to the other digits.

The mechanism of dorsal dislocation is one of hyperextension, with resultant rupture of the volar plate, capsule, and at least a portion of the collateral ligaments. Rupture of the volar plate usually occurs proximally, but may be intra­substance or distal to the sesamoids. Under local anesthetic or joint insufflation, closed reduction for dorsal dislocations of the thumb MCP joint is performed with the metacarpal flexed and adducted and then the MCP is hyperextended. Manual pressure is applied from dorsal to volar on the base of the proximal phalanx to translate the phalanx and its attached volar plate over the metacarpal head. Coronal and sagittal plane stability are then assessed clinically, and reduction is confirmed with dedicated radiographs of the thumb.

When there is grade 1 to 2 collateral laxity, a thumb spica cast is applied with the MCP joint in mild flexion, and the IP joint may be left free. Motion is initiated at 3 to 4 weeks. Some prefer dorsal block splinting in 10 degrees more flexion than the point of sagittal plane instability followed by weekly reduction of the dorsal block. If there is grade 3 collateral ligament rupture, operative repair or reconstruction is considered.

Closed reduction is more often successful in the thumb than the other fingers. This phenomenon may in part be due to the absence of a deep transverse intermetacarpal ligament in the thumb that may maintain the volar plate dorsally.

Irreducible dorsal dislocations in the thumb are often due to interposition of the volar plate, sesamoids, or flexor pollicis longus. Irreducible dorsal thumb MCP dislocations are treated with open reduction through a dorsal exposure between the EPL and EPB. Open dorsal dislocations typically present with a volar wound, which is then extended to allow for débridement and open reduction. Volar plate repair can be performed through this volar exposure. In the subacute or chronic setting, a combined approach may be needed. Volar dislocations are rare and more often require open reduction.

MCP stiffness is a common sequela of dislocation. Patients are counseled that recovery of motion can be slow, and that stability is more essential than full motion. Symptomatic chronic volar plate insufficiency is uncommon. When it occurs, reconstructive options include proximal advancement of the volar plate to the retrocondylar fossa and volar capsulodesis with suture anchor fixation and joint transfixion for 3 to 4 weeks; APB/FPB distal advancement along the volar-radial aspect of the proximal phalanx; and graft reconstructions for multidirectional instability.

Regional Anatomy

The metacarpals are structurally divided along their longitudinal axes into a base, shaft, neck, and head. The bases create the foundation and are approximately twice as wide as the shaft in the coronal plane. The congruent articulations and stout capsule-ligamentous condensations about the trapezoid, capitate, and corresponding index and long finger metacarpals are responsible for the relative rigidity in these CMC joints. In contrast, the sagittal plane mobility in the ring and small finger metacarpals allowing for power grip is derived from the modified saddle joint between the hamate articular facets and the corresponding bases of the ring and small finger metacarpals. The distal articular surface of the hamate contains two concave facets separated by a sagittal ridge. The base of the fifth metacarpal consists of a concave-convex facet that articulates with the hamate and a flat radial facet that articulates with the fourth metacarpal base. The ulnar CMC joints therefore not only accommodate a 20- to 30-degree flexion-extension arc, but also a slight rotatory motion that aids in allowing the small finger to contact the thumb. There is now expanding anatomic and kinematic data on the finger through small finger CMC joints. Viegas and colleagues detailed the osseous anatomy of the CMC joints. Nakamura and colleagues highlighted the ligamentous anatomy, which is reviewed in the following section. El-Shennawy and colleagues elucidated the three-dimensional kinematics of the index through small finger CMC joints and their clinical relevance.

The metacarpals are tubular bones extending from the carpal arch to form the breadth of the hand. They extend distally with a dorsal convexity. Their coronal and sagittal plane geometry creates the longitudinal and transverse arches of the hand. The sagittal plane bow and transverse arch must be understood and restored when performing percutaneous transmetacarpal pinning.

The concave palmar cortex is denser and experiences compressive loads with functional loading. Plating is usually performed dorsally along the tensile side of the metacarpals. The rigid central pillar projects through the index and long finger metacarpals. The thumb and ring and small finger metacarpals and their respective CMC joints form the mobile borders of the palm.

The metacarpal neck represents the transitional zone between the shaft and articular head. The metacarpal head represents a curve of increasing diameter from the dorsal to volar. Additionally, the articular head in the coronal plane is wider on the palmar aspect, creating a “pear-shape” to the head. The dorsal corridor of the metacarpal head is in line with the medullary canal, and this anatomic relationship has implications when performing percutaneous and open longitudinal intramedullary fixation of shaft and neck fractures.

The collateral ligaments originate dorsal to the axis of MCP flexion from their respective radial and ulnar collateral recesses of the metacarpal head and insert broadly along the volar aspects of the proximal phalangeal base. Their eccentric origin and coronal and sagittal plane asymmetry of the head account for the collateral ligaments being more lax in extension and taut in flexion (i.e., cam effect) ( Fig. 40.18 ). This phenomenon is the rationale for splinting of the MCP joints in flexion to minimize capsuloligamentous contracture and stiffness. Similar to the IP joints, there is a dorsal proper collateral and a more palmar accessory collateral ligament.

An understanding of the intricate extrinsic and intrinsic anatomy elucidates expectant osseous deformity after fracture, the impact of osseous deformity on myotendinous imbalance between the intrinsic and extrinsic systems, and surgical exposures at various levels along the longitudinal axis of the metacarpals. The dorsal and palmar interossei fill their corresponding intermetacarpal spaces. Isolated diaphyseal fractures may have inherent stability because of the origins of the dorsal and palmar interossei and the stabilizing effect of transverse intermetacarpal ligaments distally. The extrinsic flexor and extensor tendons contribute deforming forces. On the dorsal surface of the hand lie the extensor tendons of the fourth and fifth extensor compartments (i.e., extensor digitorum communis [EDC] of index through small fingers, extensor indicis proprius, and extensor digiti minimi). A potential subaponeurotic space exists between the undersurface of the extensor tendons and investing fascia of the dorsal interossei. Additionally, the radial wrist extensors of the second compartment (i.e., extensors carpi radialis longus and brevis) and the extensor carpi ulnaris of the sixth compartment insert at the base of the index, long, and small finger metacarpals, respectively, and may be deforming forces in fractures about these CMC joints.

The communis tendons are joined distally near the MCP joints by fibrous interconnections, the juncturae tendineae. The juncturae tendineae orientation changes during MCP joint motion. Whereas the juncturae are oblique in MCP extension, they adopt a transverse orientation during MCP extension and contribute stability to the extensor hood. The extrinsic extensors join the dorsal aponeurosis at the level of the MCP joints. The radial and ulnar sagittal bands of the extrinsic system pass volarward from the extensors and insert onto the volar plate and volar base of the proximal phalanx and aid in MCP extension. The intimate association of the central extensor tendon and its articular fibers with the dorsal capsule at the level of the metacarpal neck and dorsal articular margin creates challenges during ORIF of metacarpal neck and subcapital fractures. Placement of fixation to the level of the articular margin can create extensor tendon adhesions and capsular contracture ( Fig. 40.19 ).

The transverse and oblique fibers are located distal to the sagittal bands and are part of the intrinsic system. They arise from the lateral bands and arch dorsally and aid in phalangeal flexion. The contributions to each lateral band by the volar and dorsal interossei (deep head) and lumbricals vary by finger. The interossei pass dorsal to the deep transverse metacarpal ligament, whereas the lumbricals pass volar. The intricate extrinsic and intrinsic extensor tendon anatomy responsible for IP joint extension is reviewed in the section on phalangeal fractures and IP joint injuries. For a detailed discussion of the intrinsic system of the hand, the reader is referred to the classic works of Emanuel Kaplan, and Richard J. Smith.

Examination

Examination of the hand reveals swelling and ecchymosis. Diaphyseal fractures typically present with apex dorsal deformity, which can be appreciated clinically. The soft tissue envelope is inspected for associated abrasions, lacerations, and fracture blisters. The cascade is examined with active motion, if the patient can tolerate it, with the tenodesis maneuver to assess for angular and rotational deformities. Combined injuries are examined for flexor and extensor function and associated neurovascular injuries.

A complete radiographic series of the hand includes PA, lateral, and oblique views. When involvement of the ring and small finger metacarpal bases and intraarticular extension to the CMC joints is suspected, an AP view with the forearm pronated 30 to 60 degrees from full supination is helpful in assessing joint congruity in this area. CT scanning with coronal and sagittal plane reconstructions is helpful in assessing articular impaction, displacement, and subtle joint subluxation not readily visible on standard plain films. These criteria affect the decision for operative intervention. The Brewerton view is obtained when evaluating metacarpal head fractures. CT scans for these articular fractures are also helpful. MRI is rarely indicated, except in select cases of collateral ligament avulsions.

Metacarpal Base and Carpometacarpal Fractures of the Digits

Over the past decade, clinical anatomic studies have provided a better understanding of the regional anatomy of the CMC joints and the associated pathomechanics of fracture-dislocations in this area. Viegas and colleagues, followed by Nakamura and colleagues, described the osseoligamentous details of the second through fifth CMC joints. Multiple dorsal and volar ligaments were identified. A single intraarticular ligament was identified between the third and fourth metacarpals and their capitohamate articulations. Multiple distinct facets forming the articulations between the metacarpal bases and the distal carpus were common. Five different articular subtypes were identified between the fourth metacarpal and the capitate and/or the hamate. El-Shennawy and colleagues elucidated the three-dimensional kinematics of the index through small finger CMC joints and their clinical relevance.

A fist blow (i.e., axial load) is the most commonly described mechanism of trauma resulting in a constellation of intraarticular CMC fractures, CMC dislocations, or fracture-dislocations. Cain and colleagues proposed a classification of ulnar CMC fracture-dislocations. Type IA injuries included subluxation or dislocation of the small finger metacarpal base with dorsal CMC ligamentous disruption. Type IB injuries included a dorsal hamate fracture. Type II fracture-dislocations were defined by dorsal hamate comminution. A larger coronal plane fracture of the hamate comprised type III injuries. Similar to fractures at the base of the thumb metacarpal, these fractures can be conceptually divided into epibasilar, two-part (reverse Bennett), three-part, and comminuted with impaction.

Yoshida and colleagues detailed the pathomechanics of ring and small finger CMC joint injuries using a custom jig for axial loading of 20 fresh-frozen cadaver upper extremities with the ring and small finger CMC joints fixed at 20 degrees and 30 degrees of flexion, respectively. The most common fractures were a dorsal capitate fracture and a middle metacarpal dorsal base fracture. The most common combinations of fractures were dorsal capitate and dorsal hamate fractures. Multiple fractures often were identified in a number of locations including dorsally: the capitate, hamate, and index through small metacarpal bases; and volarly: the hook of the hamate and the middle through the small metacarpal bases. Based on anatomic dissections, the patterns of injuries encountered at the ring and small CMC joints were explained by the direction and force of the applied load, position of the CMC joint at the time of loading, and the constraints imposed by specific CMC ligaments. These results highlight that ring and small CMC fracture-dislocations are a more complex combination of fractures than identified by plain radiographs alone. A combination of axial load and shear stresses creates variable carpal fractures and ligament avulsion fractures, as well as frank fracture-dislocations. This study, and our experience, suggests that CT with coronal and sagittal plane reconstructions is the preferred diagnostic imaging method for complete assessment of these injuries. CT identifies occult fractures and allows assessment of articular impaction, displacement, and subtle joint subluxation not readily visible on standard plain films. Multiple CMC dislocations and fracture-dislocations represent high-energy injuries, and multiple combinations have been reported (i.e., convergent, divergent).