Early Experience with a Stabilized Saddle TM Hemiarthroplasty
Jorge Luis Orbay, MD; Francisco Rubio, MD; Lauren Vernon, PhD; The Miami Hand and Upper Extremity Institute, Miami, FL
Introduction: The goal in the treatment of Trapeziometacarpal (TM) arthritis is to alleviate pain while maintaining function. Current surgical options address these goals in a limited manner as arthrodesis limits motion, trapezial excision limits strength and available implant arthroplasties have failed or have demonstrated limited survivorship. Total joint TM replacements have shown that failure often occurs at the trapezial side. Ball and socket hemiarthroplasties also fail as they subside into the soft trapezium. We have used a stabilized saddle shaped TM hemiarthroplasty (Stablyx ®, Skeletal Dynamics, Miami Florida) for surgical management of TM osteoarthritis. The metacarpal joint surface is replaced with a metallic implant; the trapezium is reshaped for proper articulation (Trapezioplasty) while preserving most of the strong subchondral plate. Stability is provided by a saddle geometry and a by a 30deg dorsal redirection of the articular surface, along the lines of the Wilson osteotomy. We present our initial experience with the Stablyx ® CMC hemiarthroplasty system.
Materials & Methods: 42 patients were treated for CMC OA using the Stablyx ® CMC hemiarthroplasty system and followed for a minimum of 12 months. Grip and pinch strength was measured in comparison with the contralateral hand. QuickDASH scores were taken to assess function/ disability. Range of motion was evaluated using the Kapandji scoring system. Passive (while resting) and active (while opening a jar) pain was evaluated using a 10-point visual analog scale (VAS).
Results: 39 patients were evaluated after 12 months, 12 patients were evaluated after 24 months. The average grip strength was 83.2% of the contralateral hand at 12 months and 99.3% at 24 months. Similarly, the average pinch strength was 87.2% of the contralateral hand at 12 months and 97.7% at 24 months. QuickDASH scores were 15.9 at 12 months and 2.27 at 24 months. Kapandji scores of 9.03 and 9.17 were achieved at 12 and 24 months respectively. At 12 months, passive and active pain was reported as 0.44 and 2.80 respectively. By 24 months, passive and active pain was reported as 0.04 and 0.36 respectively.
Conclusion: Our early results of treating TM osteoarthritis with a stabilized saddle hemiarthroplasty are encouraging. Pain relief, as measured by VAS scores, is comparable with the historical results of trapezial excisional procedures. DASH scores, strength and motion seem to compare favorably. We will continue to follow these patients to see how these results stand up to the test of time.
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