Natural History of Metacarpal Subsidence following Trapeziectomy and Its Relationship to Clinical Outcomes.

METHODS

An institutional review board-approved retrospective review of patients who underwent trapeziectomy and ligament reconstruction and tendon interposition (LRTI) was conducted. Patient demographics, visual analogue scale pain scores, grip strength, pinch strengths, and radial and palmar abduction were collected. The trapezial space ratio (TSR) was measured by the scaphometacarpal distance divided by the length of the capitate. Subsidence [(postoperative TSR - preoperative TSR)/preoperative TSR] was measured and classified as severe (≥70%) or mild to moderate (<70%). Median rate of subsidence increase was calculated. Conolly-Rath scores were used to evaluate the proportion of good outcomes in each group.

RESULTS

A total of 141 trapeziectomies with LRTI were included. Subsidence increased 6.7% (5.4% to 23.0%) per week before 16 weeks and 0.3% (0.1% to 0.8%) per week thereafter. Visual analogue scale pain scores were not significantly different between patients with severe or mild to moderate subsidence ( P = 0.25) 16 weeks after thumb mobilization. The proportion of good outcomes was comparable between the two groups ( P = 0.12). There was no correlation between subsidence and pain (ρ = -0.20; P = 0.24), grip (ρ = -0.02; P = 0.93), key (ρ = -0.13; P = 0.62), tripod (ρ = 0.16; P = 0.71), or index tip pinch strengths (ρ = -0.28; P = 0.43) or radial (ρ = -0.03; P = 0.92) or palmar (ρ = -0.15; P = 0.61) abduction.

CONCLUSIONS

Subsidence occurs in all patients after trapeziectomy and LRTI, stabilizing 16 weeks after mobilization. Degree of subsidence does not correlate with postoperative outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.