Thumb Metacarpal-Trapezoid Impingement as an Etiology of Pain After Trapeziectomy and Basal Joint Soft Tissue Arthroplasty: A Case Series.

ABSTRACT

PURPOSE: To report a poorly described etiology for pain after trapeziectomy and soft tissue basal joint arthroplasty, diagnosed with the aid of nuclear imaging. METHODS: Five patients (4 women and 1 man), average age 62 years (range, 59-65 years) presented with pain an average of 7 months (range, 2-11 months) after basal joint arthroplasty. The dominant hand was involved in all cases. Advanced imaging including 25 mCi 99mTc methylene diphosphonate bone scintigraphy and single-photon emission computed tomography (CT) showed intense tracer uptake between the base of the thumb metacarpal and residual trapezoid. Computed tomography scans confirmed abutment between these bones. The symptoms were attributed to this finding, and revision surgery consisting of excision of the trapezoid and arthrodesis of the index and middle finger carpometacarpal joints was performed. RESULTS: Mean follow-up was 40 months (range, 12-60 months). Grip strength improved from a mean of 10.5 to 23 kg, and lateral pinch strength improved from a mean of 3 to 6.75 kg. Radiographic fusion of the index finger metacarpal to capitate was confirmed in 4 of 5 patients; it was indeterminate in one patient who was completely pain-free. Radiographic fusion of long finger carpometacarpal joints was indeterminate in 3 patients. Patient-Rated Wrist Evaluation pain scores improved from 35 to 6, Patient-Rated Wrist Evaluation function scores from 78 to 14, and Quick-Disabilities of the Arm, Shoulder, and Hand scores from 37 to 18. CONCLUSIONS: Impingement between the base of the thumb metacarpal and remaining trapezoid should be considered a potential source of pain after trapeziectomy and soft tissue arthroplasty. Advanced imaging (bone scintigraphy and single-photon emission CT and standard CT) are helpful to confirm the diagnosis. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic V.