Reconstruction of Chronic Radial and Ulnar Instability of the Thumb Metacarpophalangeal Joint
DEFINITION
Chronic instability of the ulnar collateral ligament (UCL) and the radial collateral ligament (RCL) of the metacarpophalangeal (MCP) joint of the thumb usually results from unrecognized or untreated acute tears of the ligament. Much less commonly, it results from chronic, repetitive trauma which, over time, renders the ligament incompetent.
Persistent laxity may cause pain and weakness and, eventually, osteoarthritis resulting from asymmetric wear of the articular cartilage.
ANATOMY
The MCP joint of the thumb has characteristics of both a condyloid and a ginglymus joint. The radial condyle is taller in the dorsovolar dimension than the ulnar condyle.
The dorsoulnar and dorsoradial digital nerves are terminal branches of the superficial sensory branch of the radial nerve and invariably cross the operative field in the plane immediately superficial to the adductor and abductor aponeuroses, respectively.
They are at risk during reconstruction of the collateral ligaments. During the exposure of the joint, the nerve should be mobilized and gently retracted. Forceful retraction may cause a neurapraxia and hypesthesia distal to the nerve on the dorsum of the thumb on the involved side.
The adductor aponeurosis is an extension of the tendon of the adductor pollicis muscle, which contributes obliquely oriented fibers to the extensor mechanism distal to the vertical fibers.
The abductor aponeurosis is an extension of the tendon of the abductor pollicis brevis muscle, which contributes obliquely oriented fibers to the extensor mechanism distal to the vertical fibers.
The proper UCL and RCL originate from fossae of the condyle of the metacarpal head on the radial and ulnar sides and pass obliquely from dorsal-proximal to volar-distal to insert on the volar third of the base of the proximal phalanx. The ligament widens as it goes from its metacarpal origin to its proximal phalangeal insertion.
The proper collateral ligaments are tight in MCP joint flexion and lax in extension.
The accessory collateral ligaments originate on the metacarpal head contiguous with but just volar to the proper collateral ligament and extend obliquely across the MCP joint, inserting on the sesamoid and volar plate.
The accessory collateral ligaments are tight in extension and lax in flexion.
By definition, to have a complete ligament rupture, both the proper and the accessory collateral ligaments must be torn.
The Stener lesion is a palpable soft tissue mass on the ulnar aspect of an injured MCP joint. It results from a tear of the UCL caused by forceful radial deviation of the proximal phalanx, angulating the MCP joint 70 degrees or more. The ligament tears distally at or near its insertion on the volar ulnar base of the proximal phalanx. As
the proximal phalanx deviates radially, the ruptured UCL remains attached to its metacarpal origin. As the proximal phalanx returns to its resting, neutral position, the UCL stump comes to lie proximal and superficial to the adductor aponeurosis. Hence, the avulsed ligament is separated from its deep insertion by the aponeurosis, preventing ligament healing.
The abductor aponeurosis is wider than the adductor aponeurosis. When the RCL tears, the ends of the torn ligament remain deep to the abductor aponeurosis. Hence, a Stener type of lesion rarely occurs on the radial side.
Tears of the collateral ligaments result in rotatory deformities of the MCP joint. When one ligament is torn and the other is intact, the metacarpal head subluxates volarly on the injured side, rotating around the axis of the intact ligament. The metacarpal head on the injured side appears to be prominent due to the volar translation of the base of the proximal phalanx on that side.
PATHOGENESIS
The UCL of the MCP joint of the thumb is usually torn by forceful abduction and extension of the thumb, as in a fall on the outstretched hand with the thumb abducted. The proximal phalanx deviates radially and, if there is sufficient force, the UCL either avulses from its insertion on the base of the proximal phalanx or, less commonly,
tears in its midsubstance or from its origin on the metacarpal head.19 There are four primary causes of chronic instability of the UCL.
Failure to diagnose an acute, complete tear resulting in no treatment
Failure to diagnose a Stener lesion resulting in inadequate, nonoperative treatment of a recognized acute, complete, and displaced tear
Inadequate treatment or insufficient immobilization of a recognized, acute tear without a Stener lesion Progressive attenuation of the ligament due to repetitive trauma
Tears of the RCL typically result from forceful ulnar deviation and extension of the MCP joint.
Proximal and distal avulsions of the ligament occur with roughly equal frequency. Intrasubstance tears occur infrequently.
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Chronic instability of the RCL has three primary causes.
Most commonly, chronic laxity is due to failure to recognize an acute tear resulting in no treatment or inadequate or late treatment.
Even when the pathology is recognized, conservative management may fail because surgeons tend to be less aggressive about treatment of radial compared to ulnar-sided collateral ligament injuries.
Chronic attenuation due to repetitive trauma is uncommon but does occur.
NATURAL HISTORY
Over time, chronic tears of the collateral ligaments of the thumb MCP joints cause progressive weakness of pinch and grip due to instability and pain. There may also be increasing deformity as the proximal phalanx on the injured side translates volarly causing dorsal prominence of the metacarpal head on that side. Occasionally, the proximal phalanx deviates in the coronal plane away from the side of the injured ligament resulting in a static deformity.
Incompetence of the UCL diminishes the thumb's ability to act as a stable post against which to pinch with the index finger. Patients often have difficulty holding large objects that require counterpressure by a stable thumb.
Patients with chronic RCL instability often have pain with torsional motions such as unscrewing jar tops.
Chronic laxity may cause incongruity and asymmetric wear of the MCP joint, which may progress to posttraumatic osteoarthritis of the joint.
Arthritis of the joint causes increasing pain, stiffness, and weakness.
PATIENT HISTORY AND PHYSICAL FINDINGS
Obtaining a relevant history from patients with chronic instability of the thumb MCP joint includes eliciting a history of trauma to the thumb in the recent or distant past.
Patients are questioned about pain in the thumb, particularly if it is exacerbated by forceful pinch and grasp and torsional activities such as turning keys in locks, turning doorknobs, or unscrewing jar tops.
The examiner should establish the chronicity of the symptoms and whether they are increasing in severity.
Assessment of instability of the thumb MCP collateral ligaments is primarily clinical. Clinical examination begins with observation.
The resting posture of the thumb at the MCP joint is occasionally indicative of pathology. The joint may be angulated or rotated in its resting posture if the collateral ligament is grossly incompetent and the instability is chronic.
In thumbs with chronic RCL instability, there is often a dorsal prominence on the radial aspect of the metacarpal head. Such a prominence is generally less apparent in cases of chronic UCL instability.
The involved side of the joint is often tender to palpation.
Palpation of a fullness or soft tissue mass on the ulnar side of the metacarpal head is strongly suggestive of a Stener lesion.
Stability of the collateral ligament is tested in extension and 30 degrees of MCP joint flexion (under local anesthesia if needed but that is rarely required). There is no consensus in the literature concerning the degree of instability that is diagnostic of a complete tear.
Valgus stress of the MCP joint in flexion is used to assess the stability of the proper UCL, whereas stress with the joint in extension is used to assess the accessory UCL as well.
The criteria for diagnosis of a complete ligament disruption that are most accurate were described by Heyman
et al3 and include 30 to 35 degrees of laxity of the ulnar side of the MCP joint when stressed in extension and 15 degrees more laxity than the contralateral thumb when stressed in 30 degrees of flexion.
Laxity in extension suggests that the accessory and proper collateral ligaments are both torn.
A more subtle, but often very helpful, finding is the presence or absence of a discrete end point to joint opening when stressed. Absence of a solid end point is strongly suggestive of a complete ligament tear.
To test for joint degeneration, the MCP joint is passively moved in extension and flexion radially and ulnarly deviated. The joint is axially loaded as it is moved. Crepitus and pain strongly suggest the presence of osteoarthritis, a contraindication to reconstruction of an unstable MCP joint.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Radiographic evaluation includes posteroanterior (PA), lateral, and oblique radiographs of both thumbs.
Fractures should be ruled out.
The lateral view may show volar subluxation of the MCP joint, which is fairly common and may be the result of extension of the collateral ligament tear to involve the dorsal capsule. This may occur with both UCL and RCL tears. An isolated tear of the dorsal joint capsule very rarely causes volar subluxation without an associated collateral ligament injury.
A comparison lateral radiograph of the contralateral thumb is very helpful if volar subluxation is suspected.
Stress views of the MCP joint have been recommended to demonstrate instability radiographically.
Most experienced clinicians rely almost exclusively on physical examination and static plain radiographs to make the diagnosis. Stress views done by the treating surgeon can be used to confirm the diagnosis and provide documentation for the medical record.
Magnetic resonance imaging (MRI), ultrasound, and arthrography are rarely indicated to assess completeness of the UCL tear, particularly in the setting of a chronic injury. MRI and ultrasound can show the presence of a Stener lesion, but in the setting of a chronic injury, the presence or absence of a Stener lesion does not substantially alter the treatment plan.
The use of arthroscopy as a diagnostic and treatment modality in the setting of chronic UCL instability remains investigational. Although the ligament and joint pathology may be able to be visualized, reconstruction using the arthroscope is a challenge, which has not yet yielded reportable results.
DIFFERENTIAL DIAGNOSIS
Fracture of the thumb metacarpal head or base of the proximal phalanx Synovitis of the MCP joint
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Chronic partial tear of the UCL or RCL MCP joint arthrosis
NONOPERATIVE MANAGEMENT
Customized hand-based thermoplastic splints, nonsteroidal anti-inflammatory medication, and corticosteroid injections may improve the synovitis and pain resulting from chronic instability and early degenerative arthritis. The duration of pain relief is unpredictable but usually in the range of a few weeks to months.
SURGICAL MANAGEMENT
The indication for reconstruction of chronic UCL or RCL disruption is failure of conservative treatment, with persistent pain and instability of the MCP joint.
Instability alone is a soft indication for surgery.
Theoretically, the asymmetric wear of the articular cartilage resulting from chronic laxity causes degeneration of the articular cartilage. This can be used as an argument for prophylactic reconstruction.
However, most patients without pain are hesitant to consider surgery and the prolonged rehabilitation
required thereafter.
Contraindications to reconstruction of UCL or RCL tears include osteoarthritis, “multidirectional” instability, and fixed subluxation of the joint.
Mild chondromalacia is not a contraindication to reconstruction but more significant cartilage degeneration is better treated by MCP arthrodesis.
If an arthritic joint is stabilized by reconstruction, pain is likely to persist and increase over time, necessitating conversion to an arthrodesis.
Fixed instability of the MCP joint is an uncommon contraindication to ligament reconstruction.
Reconstruction of the incompetent ligament in this scenario would require an extensive joint release, creating multidirectional instability.
Failure to release the joint adequately would preclude anatomic realignment or result in rapid recurrence of the preoperative deformity and instability.
Reconstruction of chronic instability may involve mobilization of the disrupted ligament, mobilization of local tissues, or ligament replacement using a tendon graft.
The decision is made at the time of surgery.
The more chronic the injury and the more dramatic the laxity and deformity, the more likely the need for replacement of the ligament with a graft. The prevailing wisdom is that if an MCP collateral ligament has been torn for more than 6 weeks, it cannot be used for secondary repair or reconstruction. I have not found that to be the case. I have used ligaments torn for as much as several months for secondary repair but the tissue has to be supple and able to be mobilized. Significantly, fibrotic ligament should be excised and reconstructed.
Preoperative Planning
The patient is asked to actively bring all five digits together and simultaneously flex the wrist against resistance. The volar wrist is inspected for the presence of a palmaris longus (PL) tendon.
Examination under anesthesia may show even greater joint laxity than anticipated based on an awake examination with the patient guarding.
Positioning
The patient is supine on the operating room table with the arm on a hand table at an angle slightly less than perpendicular to the torso.
Approach
Lazy S incision centered over the MCP joint Midaxial incision
Chevron-shaped incision centered over the midaxial point of the MCP joint
TECHNIQUES
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Reconstruction of Chronic Ulnar Collateral Ligament Disruptions Using Tendon Graft
Exposure
Incise the skin over the ulnar joint line (TECH FIG 1A,B). Elevate skin flaps and retract them with 4-0 silk sutures.
Identify and protect the branch of the dorsoulnar digital nerve that invariably crosses the wound (TECH FIG 1C).
Identify the frequently fibrotic adductor aponeurosis.
The proximal stump of the torn UCL may be visualized at the proximal margin of the adductor aponeurosis if a Stener lesion is present.
Incise the adductor aponeurosis longitudinally, exposing the underlying torn UCL (TECH FIG 1D).
If the ligament cannot be defined and mobilized sufficiently for direct repair or reinsertion, the remnant of the ligament is excised, exposing the ulnar side of the distal metacarpal head, the base of the proximal phalanx, and the MCP joint (TECH FIG 1E).
The MCP joint is “booked open” to visualize the articular cartilage.
Significant degenerative disease is a contraindication to reconstruction. Mild chondromalacia can be tolerated and is not necessarily a contraindication to reconstruction (TECH FIG 1F).
Bone Preparation
Make two holes in the ulnar base of the proximal phalanx using handheld gouges of increasing diameter (TECH FIG 2A). Alternatively, a drill can be used to make the holes using a drill guide or tissue protector to prevent wrapping up adjacent tissue.
The diameter of the hole required depends on the size of the tendon graft to be used for reconstruction. The preferred donor is the PL, which is usually fairly thin and can fit in a relatively small hole.
The gouge holes must be made far enough apart to preserve a substantial bony bridge between the holes.
A bridge that is too narrow can fracture during passage of the tendon graft.
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TECH FIG 1 • A. The lazy S incision used for UCL reconstruction. The proximal incision is dorsal and the distal incision is midaxial. B. A chevron-shaped incision is made centered over the ulnar side of the MCP joint. C. A dorsal ulnar sensory nerve branch is identified and protected throughout the surgery. D. The adductor aponeurosis is incised longitudinally about 2 mm from the extensor expansion, providing a cuff of tissue dorsally to facilitate an adequate repair at the end of the procedure. E. Excision of the UCL remnants exposes the MCP joint, the metacarpal head, and the base of the proximal phalanx. F. The MCP joint is inspected for degenerative changes. Extensive degenerative disease is a contraindication to reconstruction. Arthrodesis is appropriate in the setting of an arthritic MCP joint. This joint shows no evidence of arthritis.
Place the holes at the 7 o'clock and 11 o'clock positions in the base of the proximal phalanx if looking at the right thumb end on. Make the holes at an angle of about 45 degrees to the bone surface and direct them toward each other in order to converge within the medullary canal and create a bone tunnel.
Prebend a 28-gauge stainless steel wire into the approximate arc of curvature of the bone tunnel to facilitate its passage. An alternative to wire is a 0 polypropylene nonbraided synthetic suture. Leave the needle on the suture and pass the back end of the needle through the bone tunnel. The sharp end of the needle tends to get caught up by the trabecule in the medullary canal more readily.
Pass the wire through the bone tunnel and secure the ends with a hemostat.
Create a second bone tunnel in the metacarpal neck. Use the gouges beginning at the fossa from which the UCL normally originates on the ulnar side of the metacarpal neck and extending slightly obliquely, from distal to proximal, across the metacarpal, exiting radially (TECH FIG 2B,C). A 1-cm longitudinal incision is
made over the tip of the gouge to provide access to the gouge hole and periosteum adjacent to it.
Most often, the small, medium, and large gouges are used to create one large hole because both ends of the tendon graft are passed through this hole.
A second 28-gauge stainless steel wire is placed through this bone tunnel and the ends are secured with another hemostat.
Preset a 0.045-inch Kirschner wire (sharp at both ends) in the metacarpal head for later advancement across the MCP joint.
Radially deviate the proximal phalanx to expose the metacarpal head.
Starting in the center of the metacarpal head and aiming at an angle of about 45 degrees, advance the wire retrograde through the radial cortex of the metacarpal shaft and then withdraw it proximally until it is just below the articular surface of the metacarpal head.
Tendon Graft Harvest and Passage
Harvest the PL for use as a graft.
If the palmaris is absent, use half of the flexor carpi radialis (FCR) tendon or the plantaris tendon. The obvious advantage of the FCR is its availability without requiring a second surgical site.
Make a short transverse incision over the PL tendon at the distal wrist flexion crease (TECH FIG 3A) and mobilize the tendon distally.
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TECH FIG 2 • A. The proximal phalangeal holes are made at the 7 o'clock and 11 o'clock position; the surgeon must be careful to make a wide bone bridge to avoid fracture. A 28-gauge wire is placed into the bone tunnel to assist with passage of the tendon graft. B. A large gouge is used to create a single hole in
the metacarpal head. An incision is made radially over the end of the gouge to allow for fixation of the graft.
C. The adductor aponeurosis has been divided and the collateral ligament remnants have been excised. Gouge holes have been made in the base of the proximal metacarpal head.
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TECH FIG 3 • A. If it is present, the PL tendon is harvested with two small transverse incisions. Great care is taken to protect the median nerve during harvest. B. The wire is tied over the end of the tendon graft and is used to pull the graft through the bone tunnel in the proximal phalanx for reconstruction of the RCL in this case. C. The PL tendon is placed through the proximal phalangeal holes using the previously placed wire. Care is taken not to pull against the bone bridge during graft placement. D. Both ends of the tendon graft are passed together through the hole in the metacarpal head. E. The graft has been passed through the gouge holes and is secured on the radial side of the thump MCP joint by tying the ends into a knot; it is further secured with sutures to local tissue. F. The graft ends are tied into a knot and secured to the local periosteum with 3-0 nonabsorbable suture. (continued)
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TECH FIG 3 • (continued) G,H. Anteroposterior (AP) and lateral radiographs verify concentric joint reduction and proper placement of the transfixing 0.045-inch Kirschner wire. The Kirschner wire is left in place for 6 weeks. I. The tendon graft is sutured to the dorsal and volar remnants of the native collateral ligament for additional fixation. J. The adductor aponeurosis is repaired with 5-0 absorbable suture. This
layer must be repaired separately from the collateral ligament as differential gliding between the two layers occurs with thumb motion.
Make a second, proximal incision over the PL musculotendinous junction and mobilize the tendon at this level and under the skin bridge.
Use of a tendon stripper is an alternative method of harvest.
After incising the PL as distal as possible, apply firm traction and withdraw the tendon through the proximal incision, and then divide the tendon at the musculotendinous junction.
Secure the tendon graft to the limb of the stainless steel wire emerging from the more volar of the two proximal phalangeal gouge holes by tying a knot around one end of the tendon graft (TECH FIG 3B) or by using a grasping suture placed through the graft.
Moisten the tendon graft with saline.
Pull the wire to draw the tendon into and through the bone tunnel, emerging from the dorsal hole (TECH FIG 3C).
The tendon is pulled using moderately firm traction and a circular motion of the wire.
Avoid fracturing the bony bridge between the gouge holes by pulling too firmly on the wire with a vector of pull away from the bone.
The wire is removed from the end of the tendon.
Remove this wire and tie the ulnar end of the wire previously placed in the metacarpal bone tunnel around both ends of the tendon graft.
Using the same technique combining saline lubrication, traction, and rotation of the wire, bring the two ends of the graft together and through the metacarpal gouge hole, exiting radially (TECH FIG 3D,E).
Set the tension of the reconstruction by pulling on both limbs of the graft simultaneously and stressing the joint with radially directed force on the proximal phalanx.
Flexion and extension should not be limited significantly and the joint should open minimally with stress.
When the desired tension is achieved, tie the ends of the graft in a knot (TECH FIG 3F).
Suture the knot to the adjacent periosteum with two mattress sutures stitches of 3-0 braided synthetic suture.
Alternatively, place a bone anchor adjacent to the metacarpal tunnel on the radial side and use the loaded sutures to secure the knot.
Transfix the MCP joint by driving the previously placed Kirschner wire antegrade, across the joint into the proximal phalanx (TECH FIG 3G,H).
Bend and cut the proximal end of the Kirschner wire superficial to the skin.
Suture the tendon graft to the native collateral ligament remnants using 3-0 braided suture (TECH FIG 3I). Repair the adductor aponeurosis with 5-0 absorbable PDS suture (TECH FIG 3J).
Reapproximate the skin with either subcuticular 4-0 absorbable nonbraided synthetic suture such as Monocryl or interrupted, absorbable 5-0 plain suture.
A forearm-based thumb spica splint is applied, leaving the thumb interphalangeal joint free.
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Reconstruction of Chronic Radial Collateral Ligament Disruptions Using Tendon Graft
The steps used to stabilize the radial MCP joint using a tendon graft are much the same as those detailed for reconstruction of chronic UCL disruptions.
Exposure
Center the skin incision over the radial MCP joint line (TECH FIG 4A).
Identify and protect the branch of the dorsoradial digital nerve (TECH FIG 4B).
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TECH FIG 4 • A. A lazy S incision is used for RCL reconstruction. B. A dorsal radial sensory nerve branch is identified and protected.
Incise the abductor aponeurosis longitudinally, exposing the underlying torn RCL.
In thumbs with chronic instability, the RCL may be densely fibrotic and adherent to the overlying aponeurosis.
Excise the remnant of the RCL, exposing the radial side of the metacarpal head, base of the proximal phalanx, and MCP joint.
Deviate the MCP joint to visualize the articular cartilage and ensure the absence of significant arthrosis.
Bone Preparation
Using handheld gouges of increasing diameter in the manner previously detailed, make two holes in the radial base of the proximal phalanx.
The holes are made at the 1 o' clock and 5 o'clock positions in the base of the proximal phalanx if looking at the right thumb end on (TECH FIG 5A,B).
The holes are made at an angle of about 45 degrees directed toward each other to create a continuous bone tunnel within the medullary canal.
The holes must be spaced far enough apart to maintain a substantial bony bridge.
A 28-gauge stainless steel wire is passed from one hole to the other through the tunnel created in the medullary canal to be used for later passage of the tendon graft in the manner described earlier for UCL reconstruction.
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TECH FIG 5 • A. Two holes are made in the base of the proximal phalanx using a small then a medium gouge. A 28-gauge wire is placed through the bone tunnel to be used later for passage of the graft. B. An axial view of the proximal phalanx of a right thumb demonstrating the 1 o'clock and 5 o'clock positions of the gouge holes when viewed from the side. C. A single large hole is made in the metacarpal neck and another 28-gauge wire is placed through this hole, exiting ulnarly.
Create a bone tunnel in the metacarpal neck beginning at the fossa from which the RCL normally originates on the radial side of the metacarpal head and extending slightly obliquely, from distal to proximal, across the metacarpal, exiting ulnarly (TECH FIG 5C).
A second 28-gauge stainless steel wire is placed through this hole and the ends are secured with a second hemostat.
Preset a 0.045-inch Kirschner wire in the metacarpal head to be used later for transfixing the MCP joint. The pin can be passed from distal to proximal and then withdrawn into the metacarpal head proximally.
Tendon Graft Passage
Introduce the tendon graft into the prepared bone tunnels using the techniques described for UCL reconstruction (TECH FIG 6A,B).
The tension of the reconstruction is set and the graft secured in the manner reviewed. The MCP joint is transfixed and the wound closed (TECH FIG 6C).
A forearm-based thumb spica splint is applied, leaving the thumb interphalangeal joint free.
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TECH FIG 6 • A. Both tendon ends are pulled together through the metacarpal head, exiting ulnarly. B. Converging gouge holes are made at the base of the proximal phalanx and an oblique hole is made in the metacarpal head. Subsequently, the graft is passed through these holes. C. The final photograph after wound closure and pin placement.
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PEARLS AND PITFALLS |
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Traction ▪ Excessive traction on the dorsoulnar digital nerve may cause numbness, on the paresthesias, and dysesthesia on the dorsoulnar aspect of the thumb distal to the dorsoulnar incision. digital nerve
Tools ▪ Using handheld gouges gives the operator good control of the direction and progressive enlargement of the holes in the proximal phalanx and metacarpal.
Making ▪ The most important aspect of making the holes in the base of the proximal phalanx is holes in to make them wide enough apart to maintain a substantial bone bridge. the ▪ The greatest risk is making the holes too close together. The consequence is that proximal the bridge fractures when the tendon graft is pulled through the holes. When the phalanx tendon is pulled through the bone tunnel, the wire should be pulled longitudinally more or less parallel to the axis of the bone tunnel using longitudinal traction and a twisting motion. It should not be pulled up and away from the bone in a direction more |
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Graft
tension
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The graft can be made too tight, limiting motion of the MCP joint and possibly
causing pain postoperatively. The knot in the graft should be sutured after the tension has been set and felt to be appropriate. A less likely possibility is that the graft is too loose, resulting in persistent laxity of the joint.
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After the tension is set, the joint should be flexed and extended to ascertain that the reconstruction is not too tight to allow motion or too loose to adequately correct the instability.
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The wire used for passage of the tendon graft should be tied in a knot around the
end of the tendon graft using hemostats, not manually; it can cut the skin of the surgeon's fingers if done manually with too much force.
Tying the
wire
perpendicular to the axis of the bone tunnel. Pulling the wire perpendicular to the axis
of the bone tunnel will increase the likelihood of fracture of the bone bridge.
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POSTOPERATIVE CARE
The thumb is immobilized in a thumb spica splint or cast for 6 weeks postoperatively. At 6 weeks after surgery, the splint or cast and pin are removed.
The thumb is immobilized after cast removal in a customized, thermoplastic short opponens splint fashioned by the hand therapist.
The splint is worn most of the time except when the patient is exercising the thumb or is sedentary for a period of 2 weeks.
Therapeutic exercise is done with the therapist and at home and includes active and active-assisted range of motion in flexion and extension, avoiding laterally directed force on the proximal phalanx opposite the direction of the reconstruction, which would stress the reconstruction.
Patients are instructed to do 12 repetitions of range-of-motion exercise four or more times per day.
After 2 weeks, the thermoplastic splint is eliminated except for strenuous activity.
Patients continue range-of-motion exercises and begin strengthening with soft putty and light gripping. At 12 weeks after surgery, pinch and grip strengthening and light free weights are initiated.
Full, unrestricted activity is allowed 16 weeks postoperatively.
Patients are expected to regain about 80% of the range of motion of the contralateral thumb MCP joint and nearly full range of motion of the interphalangeal joint.
Key pinch strength should be more than 90% of the contralateral, uninjured thumb at final follow-up.
OUTCOMES
Reconstruction of the UCL using the technique described in this chapter produces results only slightly less favorable than UCL repair.
Range of motion of the MCP joint averaged 80% of the uninjured side. Motion of the interphalangeal joint is
often limited initially after reconstruction but at final follow-up was 94% of the unoperated thumb.2 Key pinch strength averaged 95% and grip strength averaged 103% of the unoperated thumb not corrected for handedness.2
Sixty-nine percent of patients had no pain postoperatively and the remainder had mild or intermittent pain. Eighty-eight percent of patients had no functional limitations, 8% had minimal limitations, and 2% had
moderate functional limitation.2
None of the reconstructions that had normal or minimally degenerated cartilage required revision due to development or progression of degenerative disease.2
Results of RCL reconstruction in the hands of the same authors were similar to those of UCL reconstruction, although range of motion of the MCP joint was 20% less than for UCL.1 Range of motion of the MCP joint on the operated side was 59% of the unoperated side and interphalangeal range of motion was 94% of the unoperated thumb.1
Both grip and key pinch strength were equal in the operated and unoperated thumbs.1 The MCP joints were equally stable to stress in operated and unoperated thumbs.1
Patients had minimal pain and no significant functional limitations. All returned to their preoperative
occupations.1
COMPLICATIONS
Some patients develop transient hypesthesia on the dorsal aspect of the thumb distal to the incision due to intraoperative traction on a branch of the radial sensory nerve.
This generally resolves over several weeks.
Occasionally, patients develop stiffness of the MCP joint that is persistent. This may be the result of the reconstruction being too tight.
The MCP joint occasionally develops some laxity postoperatively, which may be a consequence of the reconstruction being too loose or the patient being too aggressive during rehabilitation. Therapists should be cautioned about beginning key pinch strengthening too early or too aggressively.
The bony bridge between the proximal phalangeal gouge holes can theoretically crack intraoperatively, but this has not happened to the authors or their colleagues in practice.
If it did occur, an alternative form of fixation of the graft to the proximal phalanx would have to be used, such as suturing the graft to the adjacent periosteum, pulling it out through a gouge hole on the opposite side of the phalanx, or employing a suture anchor.
REFERENCES
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Catalano LW III, Cardon L, Patenaude N, et al. Results of surgical treatment of acute and chronic grade III tears of the radial collateral ligament of the thumb metacarpophalangeal joint. J Hand Surg Am 2006;31(1):68-75.
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Glickel SZ, Malerich M, Pearce SM, et al. Ligament replacement for chronic instability of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb. J Hand Surg Am 1993;18(5):930-941.
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Heyman P, Gelberman RH, Duncan K, et al. Injuries of the ulnar collateral ligament of the thumb metacarpophalangeal joint—biomechanical and prospective clinical studies on the usefulness of valgus stress testing. Clin Orthop Relat Res 1993;(292):165-171.
SUGGESTED READINGS
Alldred AJ. Rupture of the collateral ligament of the metacarpophalangeal joint of the thumb. J Bone Joint Surg Br 1955;37-B(3): 443-445.
Bean CH, Tencer AF, Trumble TE. The effect of thumb metacarpophalangeal ulnar collateral ligament attachment site on joint range of motion: an in vitro study. J Hand Surg Am 1999;24(2):283-287.
Breek JC, Tan AM, van Thiel TP, et al. Free tendon grafting to repair the metacarpophalangeal joint of the thumb. J Bone Joint Surg Br 1989;71(3):383-387.
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