gms | German Medical Science

Objective: Kaarela's procedure is the simple method for osteoarthritis of thumb carpometacarpal joints (CMC-OA), while is not able to prevent longitudinal instability. Furthermore, there were few studies that compared with the clinical outcomes of the homogenous interposition arthroplasty between without and with suspension. The aim of our study is to describe and to compare the clinical results between the original Karrela's procedure and a new technique with reconstruction of the dorsal intermetacarpal ligament (IML) in addition to the arthroplasty.

Methods: 21 patients (3 man and 18 women; mean age, 63y) with CMC-OA were treated by trapeziectomy and Karrela's procedure without (group K) or with IML reconstruction (group S). Clinical assessments were completed preoperatively and at 12 months postoperatively. These included subjective assessments of pain VAS (0-100), range of palmar and radial abduction, and strength of pulp pinch compared with unaffected side. Moreover, trapezial space ratio was determined by the trapezial space divided by the bone length of the proximal phalanx on the lateral X-ray immediately and at 12 months after surgery.

Results: Pain VAS significantly improved from preoperative 71.0 and 71.0 to postoperative 8.0 and 8.6 in group K and S, respectively. Both volar abduction and radial abduction did not change to a statistically significant degree in both groups. Strength of pulp pinch in group K did not significantly change, while the strength in S group had significantly improved from 73% of unaffected side to 92% after surgery. Trapezial space ratio in group K decreased by 41% from 0.18 immediately to 0.11 at 12 months after surgery. By contrast, there was a decrease of 15% of trapezial space ratio in group S, with 0.27 immediately and 0.22 at 12 months following surgery. Statistical analysis showed a significant difference for the decreased rate of trapezial space ratio between group K and S.

Conclusions: In the Kaarela's procedure, APL, interposed in trapezial space and passed through 1st metacarpal, is considered to play a part in the deep anterior oblique ligament. Moreover, the results in this study indicated that reconstruction of IML in addition to tendon interposition effectively worked against the subsidence of the 1st metacarpal. We believe that addition of IML reconstruction provide better results including pinch strength and long term stability of 1st metacarpal bone.