Christopher J. Dy, E. Anne Ouellette, and Anna-Lena Makowski
DEFINITION
The diagnostic and therapeutic challenge presented by instability of the ulnocarpal joint reflects the inherent biomechanical and anatomic incongruity of the articulation.
The triangular fibrocartilage complex (TFCC) provides the majority of anatomic and functional stability of the distal radioulnar and ulnocarpal joints.1,16
As expected, the consequences of TFCC lesions reflect a disruption of its normal function. The Hui-Linscheid procedure and the modified Herbert reconstruction are two approaches to achieve surgical stabilization of the distal radioulnar joint (DRUJ). The Hui-Linscheid reconstruction stabilizes the DRUJ by augmenting function of the ulnocarpal ligament,6 while the modified Herbert reconstruction restores the radioulnar and ulnocarpal functions of the TFCC by ligamentotaxic constraint of the ulnar carpus.3
ANATOMY
The ulnar carpus does not directly articulate with the distal ulna; instead, the ulnar carpus is suspended from the ulnar head by the TFCC.
The TFCC is a collection of soft tissue structures that stabilizes the radial-ulnar-carpal unit (FIG 1). It consists of fibers originating from the subsheath of the extensor carpi ulnaris, the ulnocarpal ligaments, the dorsal and palmar radioulnar ligaments, and the triangular fibrocartilage proper.
The TFCC provides a continuous gliding surface that spans the distal surfaces of the radius and ulna, allowing carpal movements and acting as a dynamic stabilizer of the forearm during pronation and supination.12,18 In addition to its radioulnar function, the TFCC stabilizes the ulnar side of the carpus, aids in load transference from the ulnar carpus to the ulna, and cushions ulnocarpal forces.16
The dorsal and volar distal radioulnar ligaments, which are often referred to as the marginal ligaments, help to stabilize the radioulnar joint through its extremes of motion.
While controversy exists concerning the exact role of each marginal ligament, several authors have agreed that the ligaments act in concert to stabilize the DRUJ during pronosupination.
The extensor retinaculum is a thick fibrous band of tissue that holds the extensor tendons against the distal radius and ulna to prevent bowstringing and displacement of the tendons (FIG 2). It is continuous with the palmar carpal ligament and shares connecting fibers with the flexor retinaculum just proximal to the pisiform. The extensor retinaculum attaches to the pisiform and triquetrum medially and to the lateral margin of the radius laterally. It is positioned from a radial-proximal to ulnar-distal direction.15,19
PATHOGENESIS
Injuries to the TFCC can occur secondary to trauma, such as a fall on the outstretched hand, or from degenerative changes caused by repetitive loading, especially in patients with rheumatoid arthritis. Palmer has classified TFCC abnormalities by differentiating between traumatic and degenerative pathologies, with further specification within each group.11
Dorsal subluxation of the ulnar head, with or without supination deformity of the radiocarpal complex and ulnocarpal instability, can occur with attenuation or tears of the dorsal radioulnar ligaments.16,18 The Hui-Linscheid reconstruction repairs these defects through augmentation of ulnocarpal ligament function and an optional imbrication of the attenuated dorsal radioulnar ligament.4,6
FIG 1 • The soft tissue structures encompassing the triangular fibrocartilage complex of the wrist stabilizing the radial-ulnar-carpal unit. The triangular fibrocartilage proper originates from the radius medially and attaches to the base of the ulnar styloid. Fibers originating from the subsheath of the extensor carpi ulnaris dorsally cross paths with fibers originating from the ulnocarpal ligaments volarly and blend with the triangular fibrocartilage proper.
FIG 2 • Extensor retinaculum (light blue), flexor retinaculum (shaded red), and palmar carpal ligament (dark blue). The extensor retinaculum inserts in the pisiform and triquetrum bones (1) medially and connects with the lateral margin of the radius laterally (2), causing its orientation to be radial-proximal to ulnardistal. The extensor and flexor retinaculum connects proximal to the pisiform (3). The extensor retinaculum is continuous with the palmar carpal ligament, which is superficial to and proximal to the flexor retinaculum.
Ulnocarpal instability may also result from incompetence of the ulnocarpal ligaments, either secondary to acute trauma or from accumulative attrition.1,7 The modified Herbert reconstruction addresses ulnocarpal instability by using ligamentotaxis to stabilize both the ulnocarpal and radioulnar aspects of the DRUJ.3,13
NATURAL HISTORY
Ulnocarpal instability is a relatively common finding in the general population. Approximately two thirds of asymptomatic volunteers were found to have some form of ulnocarpal instability on physical examination.10 Medical or surgical intervention is necessary if symptoms are present or are worsening.
The unstable ulnocarpal joint uses the radiocarpal joint as a pivot. The abnormal rotation in this pathologic state leads to increased pain, weakness, and loss of function during wrist supination. In addition, an ulnar-sided supination deformity may be present.
PATIENT HISTORY AND PHYSICAL FINDINGS
In both acute and chronic cases, the clinical presentation of the ulnocarpal instability consists of ulnar-sided wrist pain with or without clicking, especially with forearm pronation– supination activities, such as putting topspin on a tennis ball with a forehand shot.
There may be demonstrable laxity during supination and weakness in passive or active pronation–supination movements. These symptoms may hinder range of motion and function of the wrist.
On physical examination, patients often localize tenderness to the ulnar carpus on palpation.
The examiner should palpate the ulnar styloid.
The examiner should palpate between the ulnar styloid and triquetrum.
Visual inspection of the ulnocarpal area is important, looking for swelling and alignment of the carpal area in relation to the ulna. Swelling may be the result of acute injury. Position of tissues indicates stability or instability.
In the absence of concomitant pathology, provocative maneuvers such as Watson and shuck tests are negative.
Watson test: Pain and movement of the scaphoid despite blocking its normal capacity to flex in radial deviation is an indication of scapholunate tear or laxity.
The Shuck test is performed to evaluate lunotriquetral instabilities.
A positive piano key test indicates a complete peripheral tear of the TFCC and/or dorsal radioulnar ligament tear.
Midcarpal instability can be ruled out with a negative wrist pivot shift test, as first described by Lichtman et al.9
In patients with ulnocarpal instability, the wrist assumes an ulnar-sided supination deformity similar to that seen in rheumatoid arthritis.
A key to diagnosing ulnocarpal instability is the supination test, which is a diagnostic maneuver developed by the first author. This examination is performed by stabilizing the affected DRUJ with a firm grasp while stressing the wrist in supination and volar translation.
When the wrist is loaded axially and returned through neutral in ulnar deviation, the patient’s pain is reproduced. The wrist may also “clunk” back into reduction.
The contralateral wrist is also tested for comparison.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Standard posteroanterior and lateral radiographs have poor diagnostic value for ulnocarpal joint instabilities but can be used to rule out scapholunate interosseous ligament (SLIL) and lunatotriquetral interosseous ligament (LTIL) tears. On a pure lateral view, if there is DRUJ instability, the ulna will be dorsally positioned relative to the radius instead of being seen superimposed on the radius.
Computed tomography is useful for visualizing joint congruity and fractures as well as subluxation or dislocation of the DRUJ.
Live fluoroscopy during the supination test allows the examiner to evaluate and visualize the presence and amount of ulnocarpal joint instability (FIG 3).
The changing appearance of the triquetrum, demonstrated by its decreased length while in a position of supination, indicates ulnocarpal instability.
The pisiform’s location in relation to the triquetrum may also indicate the type of ligamentous tear or laxity by either moving together with the triquetrum during the supination test or appearing to be stationary as the triquetrum is moving.5
Triple-injection arthrography of the midcarpal row, radiocarpal joint, and DRUJ can be useful in showing SLIL or LTIL tears, TFCC tears, and ulnar-sided TFCC tears, respectively.
FIG 3 • The still photographs shown have been captured from a fluoroscopy video of a wrist with ulnocarpal instability during the supination test. A. Top of the examination cycle with the wrist in neutral position. B. Bottom of the examination cycle. In both images, the black line represents the distance between proximal edges of pisiform and triquetrum. The red line indicates the length of the triquetrum. The shorter length of the red and black lines in Bcompared with A demonstrates the ulnocarpal instability present during dynamic testing.
The findings must correlate with symptoms for accurate diagnosis.8,17
Standard magnetic resonance (MR) imaging effectively demonstrates the normal anatomy of the TFCC as well as the intrinsic and extrinsic ligaments of the wrist.
Abnormalities of these structures can be detected with experience, but the radiographic literature has reported shortcomings of standard MR in diagnosing peripheral TFCC tears.
MR arthrography, with injection of contrast into the DRUJ, has been shown as an adequate way of diagnosing peripheral TFCC tears, with a sensitivity of 85% and specificity of 76% when compared to wrist arthroscopy.14
Wrist arthroscopy is widely considered the gold standard of diagnostic studies of the wrist joint. Arthroscopic visualization allows for the determination of the size, location, and extent of ligamentous injuries of the wrist.
Comparison of arthroscopy to arthrography by Cooney2 revealed arthroscopy to be the superior method of diagnosing injuries of the TFCC and interosseous ligaments.
DIFFERENTIAL DIAGNOSIS
Fracture
DRUJ instability
Extensor carpi ulnaris subluxation
TFCC lesions
Ulnar impaction syndrome
Degenerative changes of DRUJ and ulnar carpus
Carpal instability, scapholunate tear (dorsal intercalated segment instability [DISI]), lunotriquetral tear (volar intercalated segment instability [VISI])
Tendinitis
Chondromalacia
Ligament injuries
Ulnocarpal instability
NONOPERATIVE MANAGEMENT
Conservative treatment includes the use of a removable soft leather splint that minimizes motion of the wrist, such as those originally designed for use by gymnasts.
If the patient wishes to return to athletic activities, he or she should proceed with cautious limitation while wearing a sports splint.
Although these splints allow for motion of the wrist and for the use of athletic tools, the patient must understand that he or she must reduce the intensity of activity to a level that the wrist will tolerate.
When activity levels are limited or more support is needed, such as while sleeping, a static splint is advised.
Physical or occupational therapy, including training to increase range of motion and to strengthen the muscles spanning the ulnocarpal and distal radioulnar joints, may be beneficial.
Nonsteroidal anti-inflammatories are also recommended before deciding on surgery, with an initial trial of 4 to 6 weeks.
SURGICAL MANAGEMENT
The main indication for surgery is a painful ulnocarpal joint with diminished grip or pronosupination strength (or both) that does not respond to conservative treatment.
Individuals with high demand for strong wrist function in weight-bearing supination (eg, golfers, tennis players, certain skilled labor professions) may be considered for surgery even without first receiving conservative treatment.
Preoperative Planning
The surgeon should review all imaging studies to identify any concomitant pathology of the wrist joint.
Arthroscopic examination of the wrist is generally undertaken immediately before ulnocarpal reconstruction to address any concomitant lesions or synovitis within the wrist.
Diagnostic physical examination maneuvers are repeated while the patient is under anesthesia. These maneuvers include the piano key test and ulnocarpal supination test, as described earlier.
Positioning
Using an arm board, the patient is positioned with the forearm in pronation and the elbow flexed at 45 degrees. The dorsal aspect of the wrist joint is prepared in a sterile manner.
Approach
Modified Herbert reconstruction
Exposure of the dorsal surface of the wrist joint is the only surgical approach needed for the Herbert sling repair.
The Herbert sling procedure consists of the development of an ulnar-based flap of the extensor retinaculum, advanced at a 30to 40-degree angle from distal ulnar to proximal radial by securing into the distal radial retinacular attachments.
This reduces the radioulnar joint and the carpus to the ulna with a single advancement of the extensor retinaculum (FIG 4).
Hui-Linscheid reconstruction
A standard incision on the dorsal surface of the wrist is used to access the ulnocarpal articulation, the ulnar head, and the flexor carpi ulnaris.
A tendon graft is harvested from the flexor carpi ulnaris and passed through the tunnel in the ulnar head and looped back to its proximal insertion on the pisiform.
FIG 4 • The extensor digiti quinti is relocated dorsally of the extensor retinaculum. This procedure uses ligament materials to create an effective sling, providing support to the distal radioulnar and ulnocarpal joints. The ulnar-based extensor retinaculum flap is advanced in a distal-ulnar to radial-proximal direction. Arrows illustrate the direction of the ligamentotaxis.
TECHNIQUES
MODIFIED HERBERT RECONSTRUCTION
Create a longitudinal incision over the fifth extensor compartment at the level of the wrist (TECH FIG 1A).
Incise the extensor retinaculum between the fourth and fifth compartments, taking care not to enter the fourth compartment (TECH FIG 1B).
Raise an ulnarly based flap of the distal two thirds of the retinaculum, and prepare the extensor digiti quinti (EDQ) for transposition dorsal to the retinaculum flap (TECH FIG 1C).
TECH FIG 1 • Modified Herbert reconstruction. A. A longitudinal incision over the fifth extensor compartment at the wrist is created. B. Plan the transection of the extensor retinaculum along the extensor digiti quinti. Incise the extensor retinaculum, taking care not to enter the fourth compartment. C. Raise an ulnar-based flap. Prepare the extensor digiti quinti to be transposed dorsal to the extensor retinaculum. D. The retinacular flap is sutured to the periosteum of the ulnar border on the distal radius. E. Imbricate the extensor retinaculum obliquely in a distal-ulnar to radial-proximal direction. The extensor digiti quinti should remain dorsally of the imbricated extensor retinaculum flap.
Place the wrist in neutral and apply downward force on the distal ulna to reduce the DRUJ.
Translate the retinacular flap proximally and suture it to the periosteum of the ulnar border of the distal radius using 2-0 PDS absorbable sutures (TECH FIG 1D).
Carefully imbricate the extensor retinaculum in an oblique fashion (30 to 40 degrees) from distal-ulnar to radial-proximal (TECH FIG 1E).
The EDQ is relocated dorsally of the imbricated extensor retinaculum flap.
HUI-LINSCHEID RECONSTRUCTION
Incision and Dissection
Start the incision at the level of the fifth carpometacarpal joint. Curve the incision over the ulnocarpal joint to reach the far ulnar border and continue to the middorsal forearm for exposure of the dorsal carpal ligament (TECH FIG 2A).
Locate and protect the dorsal sensory branch of the ulnar nerve (TECH FIG 2B,C).
Incise the extensor retinaculum over the sixth extensor compartment, taking care to protect the underlying extensor carpi ulnaris tendon and subsheath.
Retract the extensor retinaculum medially to expose the capsule over the ulnocarpal joint and the subluxated ulnar head, creating an ulnarly based flap of retinaculum (TECH FIG 2D).
TECH FIG 2 • Hui-Linscheid reconstruction. A. Make a slightly curving incision over the ulnocarpal joint to reach the lateral ulnar border and continue it to the middorsal forearm for exposure of the dorsal carpal ligament. B. Take care not to injure the dorsal branch of the ulnar sensory branch during the incision and throughout the procedure. C. The ulnar nerve is located volar to the incision. The extensor retinaculum is incised at the fifth dorsal compartment. Protect the underlying extensor carpi ulnaris tendon and subsheath. D. Retract the extensor retinaculum medially to expose the capsule over the ulnocarpal joint and the subluxated ulnar head, creating an ulnar-based flap. E. Incise the capsule to expose the distal radioulnar joint while preserving the dorsal radioulnar ligament and taking care not to injure the extensor carpi ulnaris. F. Drill a 0.625-inch Kirscher wire through the ulnar head in a distal-to-proximal direction. The guidewire should be inserted obliquely starting from the base of ulnar styloid and aiming toward the synovial reflection proximally.
Make a longitudinal incision in the capsule to expose the DRUJ while preserving the dorsal radioulnar ligament (TECH FIG 2E).
Drill a 0.0625-inch Kirschner wire obliquely through the ulnar head beginning near the base of ulnar styloid to the ulnar fovea proximally (TECH FIG 2F).
Placement of the Kirschner wire is confirmed visually and sequential hand awls are used to create a 4to 5-mm bone tunnel.
Tendon Graft Harvest
Locate the flexor carpi ulnaris (FCU) in the incision distally and trace it to the musculotendinous junction. This will allow about 10 cm of tendon graft for harvest (TECH FIG 3A).
If needed, a separate longitudinal incision on the palmar area of the wrist can be used.
Alternatively, a free tendon graft from the palmaris longus or other donor area may be used if the FCU tendon is inadequate.
Split the FCU tendon longitudinally and cut the graft proximally at the musculotendinous junction. Leave the distal portion still attached at its insertion onto the pisiform (TECH FIG 3B).
Perforate the pisotriquetral capsule in a dorsal to volar direction (TECH FIG 3C).
TECH FIG 3 • Hui-Linscheid tendon harvest. A. The flexor carpi ulnaris (FCU) is located distally and traced into the muscle belly to obtain about 10 cm of tendon graft. B. Cut the FCU graft proximally, leaving the distal portion attached distally in its insertion onto the pisiform. C. Pass the FCU tendon intracapsularly. D, E. Ensure that the graft is not placing any tension on the ulnar artery or nerve.
The FCU tendon is passed intracapsularly using a tendon passer or by placing a Kessler suture into the tendon edge and using the suture to pull the tendon through the capsular perforation.
Ensure that the graft does not place any tension on the ulnar artery or nerve (TECH FIG 3D,E).
The FCU tendon graft is passed through the TFCC if it is perforated or through an enlargement of the prestyloid recess of the TFCC and through the drill hole in the distal end of the ulna.
Completion of the Reconstruction
The carpal supination and the ulnar head dorsal subluxation is reduced by pulling the FCU tendon graft taut from its pisiform insertion.
Hold this reduction by placing the forearm in supination and transfix the distal ulna to the distal radius with two parallel 0.062-inch Kirschner wires.
Close the DRUJ capsule incision using a 3-0 nonabsorbable suture.
The FCU tendon graft is pulled taut through the drill hole and then secured to the periosteum adjacent to the ulna bone tunnel using a 2-0 nonabsorbable suture.
The FCU graft is doubled back superficially to the radioulnar capsule (TECH FIG 4A) and sewn to its pisotriquetral insertion (TECH FIG 4B).
If the dorsal radioulnar ligament is found to be attenuated, imbrication of the ligament is performed.
The extensor retinaculum is imbricated using a nonabsorbable 3-0 suture.
TECH FIG 4 • Hui-Linscheid completion. A. The flexor carpi ulnaris (FCU) tendon graft is passed through the triangular fibrocartilage complex (TFCC) if it is perforated or through an enlargement of the prestyloid recess of the TFCC (1) and through the drill hole in the distal end of the ulna (2). The FCU tendon graft is doubled backed superficially to the radioulnar capsule and approached to its proximal insertion in pisiform (3). B. The FCU graft is pulled through the tunnel in the ulna and is sewn to its pisotriquetral insertion.
POSTOPERATIVE CARE
Modified Herbert Reconstruction
Six weeks in a thumb spica Muenster cast with the forearm and wrist both positioned in neutral, followed by 6 weeks in a removable thumb spica splint
Hui-Linscheid Reconstruction
Long-arm plaster cast for 6 weeks with the forearm and wrist both positioned in neutral. The cast and Kirschner wire are removed after 6 weeks.
After 6 weeks, an ulnar gutter splint with “boost” padding is applied to the ulnar head dorsally and pisiform palmarly to support the wrist between mobilization exercises (FIG 6).
FIG 6 • An ulnar gutter splint with “boost” padding applied to the ulnar head dorsally and pisiform palmarly can be used in the postoperative period to support the wrist between mobilization exercises.
General Suggestions
Gentle active rotatory motion during temporary splint removal is introduced at 6 weeks postoperatively at the patient’s discretion. Passive motion with a physical or occupational therapist is not necessary at this point.
No heavy lifting or aggressive motion is permitted until 3 months postoperatively.
Vigorous strengthening exercises to regain pronation are begun 3 months after the operation with a physical or occupational therapist at a pace with which the patient is comfortable, with exercise intensity increased gradually.
A warm, moist wrap can be used around the wrist to provide additional stretching of the wrist before activities. Ice and nonsteroidal anti-inflammatory agents can be used to provide relief after each session.
Examples of exercises:
Pronation and supination: Stretching can be achieved by holding a hammer or frying pan as a weight during the motions.
Wrist flexion and extension: Stretching can be achieved using bucket exercises. The patient places his or her arm on a table with the wrist hanging off the edge while holding an empty bucket. The bucket is filled with water until the point of discomfort. The patient holds the bucket for 2 to 3 minutes and repeats the exercise twice daily in flexion and extension.
If the patient’s preoperative activities included sports such as golf and tennis, these activities should be gradually incorporated into the strengthening program.
A Silastic sheet can be applied to aid scar remodeling. Scar massage may be started after the first 6 weeks.
OUTCOMES
Modified Herbert reconstruction
A recent long-term follow-up study, ranging from 1 month to 13 years, of 39 wrists showed that 85% of the wrists remained stable at the ulnocarpal joint (in preparation for publication).
Hui-Linscheid reconstruction
Successful short-term clinical outcomes have been reported in a small patient series by Hui and Linscheid, with patients reporting satisfactory and excellent outcomes.6
Mild limitations in pronation may be expected.
COMPLICATIONS
The sling repair can loosen if aggressive strengthening occurs too quickly.
If imbrication of the extensor retinaculum is not performed in an oblique direction, the ulnocarpal effect of the sling is lost, and a supination deformity of the wrist may occur or recur.
Pain and dysesthesias at dorsal branch of ulnar nerve: Care must be taken when placing sutures for imbrication of the extensor retinaculum to avoid injury to surrounding tissues or nerve structures.
EDQ tendinitis usually resolves 6 months after the operation.
Damage to the ulnar nerve during the surgical procedure is concerning because of its anatomic location. The nerve is immediately exposed after the opening incision and is vulnerable during drilling of the ulnar tunnel. Dorsal ulnar nerve damage ranging from irritation to neuroma may occur.
Additionally, the nerve will be passing directly over an area of soft tissue closure and may be affected by the surrounding scar tissue.
A protective covering (such as those used for recurrent nerve entrapments) to protect the dorsal ulnar nerve may minimize damage to the nerve.
Other potential complications may occur as a result of the Kirschner wire, such as migration, infection, and nerve injury.
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