Arthroscopic interposition arthroplasty of the trapeziometacarpal joint.

PURPOSE: In carpometacarpal (CMC) arthritis of the thumb, the use of interposition techniques (polylactic acid, pyrocarbon, dacron) has been increasing recently. These techniques are most often combined with open or arthroscopic complete or partial trapeziectomy. This article reports the results at one year of the arthroscopic interposition of an absorbable implant performed without trapeziectomy. METHODS: Our series included 25 patients aged 60.5 years on average, presenting with osteoarthritis of the trapeziometacarpal joint that had been medically treated for 18.5 months on average. All patients were operated using 1-ulnar (U) and 1-radial (R) portals. After joint debridement, a polylactic acid implant was inserted under arthroscopic control. Outcome evaluation consisted of the assessment of pain intensity, grip strength, pinch strength, opposition, thumb abduction and Dell radiological staging. RESULTS: The average follow-up was 14 months. Postoperative radiological data showed significant differences from baseline clinical data regarding all evaluated variables: 0.68 vs. 3.5 for pain, 24.76 Kg vs. 16.64 Kg for grip strength, 6.44 Kg vs. 3.64 Kg for pinch strength, 8.6 vs. 7.28 for opposition, 81.2° vs. 69.6° for thumb abduction, and 1.08 vs. 2.88 on the Dell stage. Eleven complications occurred, including a type 1 complex regional pain syndrome, one sepsis, and nine inflammatory reactions that resolved after an average of 3 weeks. CONCLUSIONS: Our technique is simple, rapid, cost-effective, and does not necessitate trapeziectomy, even partial. It has the same indications as other non-radical interventions. The follow-up duration of our study was too short for long-term evaluation but short-term outcome appeared superior to that in other published series. The regional inflammatory reactions that occurred in our series were transient and probably related to implant resorption. Our promising results suggest extending the indication of arthroscopic interposition to more advanced stages of proximal joint osteoarthritis.