Introduction

Injuries to the ulnar side of the wrist may be difficult to diagnose and to treat. Ulnar-sided wrist pain can occur from acute injuries, such as rotation and hyperextension, or from repetitive injuries. These injuries can result in tears of the lunotriquetral interosseous ligament (LTIOL), triangular fibrocartilage complex (TFCC), the palmar ulnocarpal ligaments, or a combination of these structures. Lunotriquetral (LT) joint injuries often exist with associated pathologic conditions such as TFCC injuries and may represent a continuum of injury severity involving the ulnar-sided wrist structures.

Arthroscopy of the wrist has been promoted as an important adjunct to the diagnosis of subtle ligamentous instability because of the ability to directly view the interosseous ligaments, secondary articular cartilage changes, and intra-articular pathology.¹ With the development of advanced techniques and improved instrumentation, wrist arthroscopy is also becoming an important tool in the treatment of complex injuries (including carpal instability).

Normal lunotriquetral kinematics are dependent on the integrity of the lunotriquetral interosseous ligament, ulnolunate ligament (UL), ulnotriquetral ligament (UT), and the dorsal radiocarpal and scaphotriquetral ligaments. The LTIOL is thick both palmarly and dorsally, with a membranous proximal portion. Injury to the LTIOL results in instability between the lunate and triquetrum.

History and Physical Exam

The initial evaluation of the wrist begins with the patient’s history, specifically reviewing mechanism of injury, hand dominance, athletic participation, work history, and recent activities. Areas of swelling, tenderness, and crepitation should be identified. Ballottement or shuck testing is often helpful in diagnosing intercarpal instability.² To perform this maneuver, stabilize the lunate or triquetrum and feel for increased motion of the LT joint during palmar and dorsal stressing. Important physical findings are tenderness over the LT joint and/or the TFCC, increased translation of the lunate with respect to the triquetrum, and crepitation with pain during pronation, supination, or ulnar deviation.

Radiographic evaluation of a painful wrist should include a zero rotation posteroanterior,^3,4 true lateral, and oblique views of the wrist. Ulnar variance, lunotriquetral interval, greater and lesser arc continuity, and the radiolunate and scapholunate angles are assessed. In cases where the physical examination findings are equivocal, an arthrogram or MRI can be obtained.

Ulnar Ligamentous Anatomy

Our approach to LT injuries had evolved from the anatomical concepts of the ulnar ligaments in relationship to the lunotriquetral joint and the TFCC. The lunotriquetral interosseous ligament is thicker both volarly and dorsally⁵ with a membranous central portion. Normal lunotriquetral kinematics is imparted from the integrity of the LTIOL,⁶ ulnolunate, ulnotriquetral,^6–8 dorsal radiotriquetral (RT), and scaphotriquetral (ST) ligaments.^6,7,9 Severe instability such as a volar intercalated segmental instability (VISI) requires damage to both the dorsal RT and ST ligaments.^6,7,9

The TFCC is the primary stabilizer of the distal radioulnar joint via the dorsal and volar radioulnar ligaments.^10,11 This helps to stabilize the ulnar carpus, and transmits axial forces to the ulna.^12,13 The TFCC originates from the ulnar aspect of the lunate fossa of the radius and inserts on the base of the ulnar styloid and distally on the lunate, triquetrum, hamate, and fifth metacarpal base. The integrity of the triangular fibrocartilage, volar radiocarpal, and dorsal radiocarpal ligaments is visible at arthroscopy. TFCC compromise is often a part of more extensive ulnar-sided injuries.¹⁴ The volar and dorsal aspects of the lunotriquetral ligament merge with the ulnocarpal extrinsic ligaments volarly and the dorsal radiolunotriquetral ligament dorsally, anchoring the triquetrum.¹⁵

The ulnocarpal volar ligaments are composed of the ulnolunate (also known as the disc-lunate), the ulnotriquetral (UT)—also known as the disc-triquetral ligaments—and the ulno-capitate. The ulnolunate and ulnotriquetral ligaments originate on the volar triangular fibrocartilage complex (TFCC) and insert on the volar lunate and volar triquetrum (respectively) as well as the LT ligament.^14,16,17 Just palmar lies the ulno-capitate ligament, providing a direct attachment from the ulna to the palmar ulnar ligamentous complex.

The arthroscopic approach to symptomatic LT instability is based on the contributing factors of the ulnar carpal ligaments to lunotriquetral joint stability. Suture plication of the ulnar ligaments serves to shorten the disc-carpal ligaments and augment the palmar capsular tissue as part of the arthroscopic reduction and internal fixation.

Ligament plication has been implemented to manage capitolunate instability.¹⁸ The central portion of the volar radiocapitate ligament was tethered to the radiotriquetral ligament by a volar approach. UT-UL ligament plication, developed by one of the authors (FHS), mimics this technique. It has been used in treating those injuries that do not severely destabilize the LT joint, such as those producing a VISI deformity that requires functional compromise of the dorsal extrinsic ligaments (dorsal radiotriquetral and scaphotriquetral). Arthroscopic volar ulnar ligament plication both reduces surgical trauma and allows concurrent assessment of its effect while viewing through the radiocarpal and midcarpal joints.

Arthroscopic Operative Technique

The following is a general approach to arthroscopic stabilization of ulnar-sided instability. It can be used in conjunction with associated pathology such as ulnar abutment syndrome and TFCC tears when associated with an LTIOL tear. 3-/,4, 6-R, volar 6-U, and the radial and ulnar midcarpal portals are used during arthroscopic capsulodesis and arthroscopic reduction and internal fixation.

An arthroscopic video system should be positioned to allow a clear view of the monitor by the surgeon and assistant. After the limb is exsanguinated, a traction tower is used and 8 to 10 pounds of traction are applied through finger traps with the arm strapped to the hand table. A complete diagnostic radiocarpal and midcarpal diagnostic arthroscopy is performed, typically utilizing the 3-/,4 and 6-R radiocarpal portals and the radial and ulnar midcarpal portals. Diagnostic radiocarpal arthroscopy should include visualization from the 6-R portal to ensure complete visualization of the LTIOL from dorsal to palmar. The LTIOL should be debrided as necessary. Depending on each unique case, the addition of a 4-/,5 portal as either the working or viewing portal can be helpful.

Midcarpal assessment begins with the arthroscope inserted into the radial midcarpal portal and the ulnar midcarpal portal as the working portal. The lunotriquetral joint is assessed for congruency and laxity of the triquetrum.

Laxity

• Assuming it is normal, the scapholunate (SL) joint can be used as a reference. Laxity should be assessed both upon triquetral rotation and separation from the lunate.

• Upon midcarpal arthroscopic assessment of an unstable LT joint, the dorsal portion of the triquetrum is often rotated such that its articular surface is distal to the lunate. The triquetrum can be translated to a reduced state in which the articular surfaces of the triquetrum and lunate are co-linear.

• An unstable LT joint may have co-linear articular surfaces. However, the triquetrum can be ulnarly translated so as to “gap open” the LT joint. The normal SL joint can be used as a reference.

The final midcarpal assessment of the LT joint is the dorsal capsular structures. The dorsal radiocarpal and dorsal intercarpal ligaments attach in part to the lunate and triquetrum. In certain cases, avulsions of the dorsal capsuloligamentous structures have been observed.

After the confirmation of LT instability, the arthroscope is placed in the 3-4 portal during disc-lunate to ulno-capitate to disc-triquetral ligament plication. The volar 6-U (v6-U) is established. The v6-U portal is located in the soft spot adjacent to the prestyloid recess, dorsal to the volar disc carpal ligaments. It is established via spinal needle localization utilizing an outside-in technique. Care is taken to avoid injury to the dorsal sensory branches of the ulnar nerve during placement.

The interval between the disc-lunate and disc-triquetral ligament identifies the lunotriquetral joint and interosseous ligament. The LTIOL is gently debrided (Figure 12.1). Through the v6-U portal, an 18-gauge spinal needle is passed just volar to the disc-triquetral, ulno-capitate, and disc-lunate—entering the radiocarpal joint at the radial edge of the UL ligament just distal to the articular surface of the radius. A #2–0 PDS suture is placed through the needle into the joint. The suture is retrieved either sequentially through the 6-R and then through the v6-U or directly through the v6-U—using a wire loop suture retriever. It is then tagged as the first plicating suture (Figure 12.2).

FIGURE 12.1 The tear in the lunotriquetral interosseous ligament is visualized. A motorized shaver is used to remove the frayed tissues.

FIGURE 12.2 (A) Diagram depicting first plication suture encompassing the UL ligament. (B) View from the 3-4 portal of the first plication suture.

(Courtesy of the Christine M. Kleinert Institute for Hand and Microsurgery).

In likewise fashion, a second plicating suture is placed approximately 5 mm distal to the first so that the suture loops are parallel to the lunate and triquetrum and tagged as the second plicating suture (Figure 12.3). Tension on the first stitch often facilitates a second needle passage through the ulnolunate and ulnotriquetral ligaments. The adequacy of the plication should be assessed by applying tension to the stitch and observing its effect on the LT interval after each suture passage.

FIGURE 12.3 (A) Placement of spinal needle superficial to the UL ligaments in preparation for passage of the second plication suture. (B) Diagram of second plication suture.

(Courtesy of the Christine M. Kleinert Institute for Hand and Microsurgery.)

Finally, through the v6-U portal a spinal needle and then a suture are passed through the volar aspect of the capsule at the pre-styloid recess and then through the peripheral rim of the TFCC. The wire retriever is introduced through the ulnar capsule and the suture is brought out the v6-U portal to tighten the ulnar capsule. The three sets of sutures are tied at the termination of the procedure after the lunotriquetral joint has been congruently reduced and stabilized with K-wires.

While viewing through the midcarpal radial portal, a midcarpal-ulnar (MCU) portal is created. A probe is used to assess lunotriquetral joint incongruity and mobility, and to reduce the lunotriquetral joint (Figure 12.4). A spinal needle can be placed in the midpalmar space from ulnar to radial across the distal aspect of the LT joint and used as a guide for percutaneous pin placement into the triquetrum. The triquetrum is reduced congruent with the lunate articular cartilage by applying traction to the plication sutures and firm pressure on the triquetrum.

FIGURE 12.4 View of the lunotriquetral joint from the midcarpal portal.

The initial K-wire should be inserted 2 to 3 millimeters proximal to the spinal needle. Two 0.045 smooth K-wires are placed percutaneously across the lunotriquetral joint (Figure 12.5). The first pin is advanced across the lunotriquetral interval from ulnar to radial under fluoroscopic guidance, and the second pin is placed using the first pin as a guide to placement. After satisfactory reduction of the lunotriquetral joint, traction is released, the forearm is held in neutral rotation, and the plication stitches are tied at the 6-U portal (with the knots placed below the skin; Figure 12.6). The K-wires are either cut subcutaneously or bent outside the skin.

FIGURE 12.5 (A) PA of the wrist after reduction of the lunotriquetral joint and stabilization with two 0.045 K-wires. Note: probe used to aid reduction. (B) Lateral of the wrist after reduction of the lunotriquetral joint and stabilization with two 0.045 K-wires.

FIGURE 12.6 View of UL ligament after plication sutures have been tied.

LTIOL tears can be seen in combination with TFCC pathology, such as traumatic peripheral tears and degenerative tears seen in isolation or as part of an ulnar abutment syndrome. In degenerative TFCC tears, the central avascular portion is debrided to a stable rim prior to plication. In traumatic tears, the suture placement through the ulnar capsule and peripheral margin can be extended dorsally to simultaneously repair the TFCC tear after the initial plication sutures are placed.

Patients with lunotriquetral ligament tears often have a positive ulnar variance.^2,20,21 In an extension of the initial treatment group, patients with ulnar abutment syndrome (with associated lunate chondromalacia, TFCC tears, and LTIOL tears) have been treated by LT plication stabilization in conjunction with an arthroscopic wafer procedure.

Postoperative Care

After surgery the patient is initially placed in a long arm splint, with the elbow flexed at 90 degrees, the forearm in neutral rotation, and the wrist in neutral flexion and extension. At approximately one week after surgery, a Muenster cast is applied—with the forearm and wrist in neutral rotation and flexion, respectively. At approximately six weeks after surgery, the K-wires are removed. A removable Muenster cast is used for an additional two weeks to allow daily gentle wrist flexion, extension, pronation, and supination within a painless arc of motion. Eight weeks after surgery, strengthening exercises are instituted and work hardening can begin slowly over 8 to 24 weeks postoperatively.

Results

In a case series, we looked at a group of 21 patients, including 7 who were treated as workman’s compensation claimants and 4 patients were competitive athletes who sustained their injury during sport. All patients complained of ulnar-sided wrist pain, which was invariably increased by use of the wrist. The mean time between the onset of symptoms and treatment was 2.5 years (range 1 week to 5.5 years). Seventeen patients recalled a specific injury (hyperextension 12, twisting 2, unknown 3), and four noted a gradual onset of symptoms. Three patients had additional significant injuries to the affected extremity: elbow dislocation, humeral shaft fracture, and anterior shoulder dislocation.

The patients were uniformly tender over the lunotriquetral joint. Provocative tests for lunotriquetral instability—such as the lunotriquetral ballotement, TFCC grind, ulnocarpal shuck, and midcarpal instability evaluation—were specifically positive in nine and for TFCC in six. Crepitus was produced with pronosupination or ulnar deviation in 10 patients. A VISI instability pattern was not present. The average preoperative Mayo wrist score was 50 and increased to an average postoperative score of 88 at a mean of 3.1 years after surgery.

Range of motion was equal to the opposite side upon final follow-up. Nineteen of 21 patients had excellent and good results, whereas 2 patients had fair results. The average postoperative score for the 7 workman’s compensation claimants or litigants was slightly lower than the overall group. Three patients had complications, which included prolonged tenderness along the extensor carpi ulnaris. One patient had a persistent neuritis of the dorsal branches of the ulnar nerve.

Summary

Symptomatic lunotriquetral interosseous ligament tears have been managed by simple arthroscopic debridement, ligamentous repair, and intercarpal arthrodesis. Ligamentous repair or reconstruction with a tendon graft requires an extensile approach. Lunotriquetral joint fusion limits flexion and extension and radioulnar deviation by 14 and 25%, respectively.²² Arthroscopic ulnocarpal ligament plication in addition to LT joint reduction and stabilization is designed to augment the volar aspect of the LT joint. LT ligament tears are often associated with other pathology, notably ulnar-carpal ligament tears and disruption of the distal radioulnar joint.²³ Suture plication of the ulnocarpal ligaments shortens their length, which acts as a check-rein to excessive lunotriquetral motion (perhaps similar to ulnar shortening procedures). Suture plication of the peripheral rim of the TFCC is thought to increase tension in the ulnar DRUJ capsule.

Postoperative improvement in comfort and function is common following the described approach for lunotriquetral instability. The use of arthroscopy allowed for a comprehensive evaluation of the injured structures, and in many cases facilitated the treatment of multiple concurrent injuries. Arthroscopic stabilization of the lunotriquetral joint is a useful technique for the treatment of LTIOL tears, with minimal loss of wrist motion and limited surgical exposure.