PRCT: Comparing Two Procedures for Ulno-Carpal Abutment Syndrome. (UAS)

A Randomized Prospective Study Comparing TFCC Debridement and Wafer Procedure With TFCC Debridement and Ulnar Shortening Osteotomy for Ulno-Carpal Abutment Syndrome. (UAS Study)

The purpose of this study is to evaluate two different currently accepted surgical treatments for UAS (ulnocarpal abutment syndrome). The hypothesis is that ulnar shortening osteotomy procedure will be associated with longer surgical time and increased complication rate when compared to the wafer procedure. It is unclear as to whether there will be a difference in functional outcome between the two groups.

Ulnocarpal abutment syndrome (UAS) (also known as ulnar impaction syndrome, ulnocarpal impingement,ulnar carpal loading) is a common cause of ulnar sided wrist pain. UAS results from increased loading of the ulnocarpal articulation and is usually associated with a positive ulnar variance. The increased loading of the joint can lead to degeneration and perforation of the Triangular fibrocartilage (TFC). Chondromalacic changes develop on the opposing surfaces of the lunate and triquetrum distally and the ulnar head proximally. A disruption of the lunotriquetral ligament may following with ensuing LT arthritis. Treatment of UAS involves decompression of the pressure and impingement, or abutment of the ulnocarpal articulation. Debridement of triangular fibrocartilage complex (TFCC) tears alone in the patient with UAS may have a failure rate of as much as 25% to 30%. Good results have been reported with combined arthroscopic TFCC debridement and distal ulnar resection. 69% excellent and 32% good results have been reported with an open limited distal ulnar resection in patients with a TFCC tear and positive ulnar variance. Similar results have been reported with both ulnar shortening osteotomy and open wafer distal ulnar resections in the UAS patient. Because these treatment choices appear to yield similar relief of symptoms, determination of the optimal treatment protocol remains a point of debate. The literature contains retrospective data comparing open wafer procedure with ulnar shortening osteotomies for the treatment of UAS. Likewise, the literature comparing arthroscopic wafer and ulnar shortening osteotomy is retrospective. However, there are, to date, no randomized prospective clinical trials comparing these types of surgery. Both types of surgery are widely accepted and the optimal treatment remains under debate. It is unclear how the techniques compare in terms of efficacy of elimination of symptoms of UAS and also in terms of relative complication rate.

A dorsal approach to the distal ulna is used dividing the extensor retinaculum between the 5th and 6th compartments. The ulnar head is exposed through a transverse capsulotomy. Cartilage and bone are resected to result in slight negative ulnar variance based on the preoperative pronated grip view. The ulnar styloid and TFCC attachments are preserved. The dorsal capsule and retinaculum are repaired in separate layers.

A longitudinal incision of approximately 8 cm is made at the distal third of the ulna along the ulnar border of the forearm. The interval between the flexor carpi ulnaris is used. The ulna is exposed at its distal third preserving the periosteum. Care is taken to protect the sensory branches of the lunar nerve. An oblique osteotomy is performed using a reciprocating saw, removing enough bone to result is slight negative ulnar variance. Fixation and compression at the osteotomy site is achieved using a 5 or 6 hole titanium LC-DCP plate.

Inclusion Criteria: persistent ulnar-sided wrist pain of a minimum of 6 months duration despite conservative management a positive ulnocarpal stress test neutral or positive ulnar variance as measured from a standard posteroanterior radiograph of the wrist central TFCC perforation or lunate chondral damage consistent with UAS based on arthroscopic evaluation arthroscopically debrided TFCC tear Exclusion Criteria: absence of a TFCC tear or lunate chondral damage repairable TFCC tear severe ulnocarpal arthrosis pre-operative diagnosis of clinically symptomatic scapholunate ligament (SL), lunotriquetral ligament (LT), or distal radioulnar joint (DRUJ) instability previous forearm or wrist fracture history of inflammatory arthritis presence of other wrist pathology a requirement for concomitant surgery for an unrelated condition skeletal maturity

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