Midcarpal and STT Arthritis in Patients with CMC Arthritis

Purpose: Carpometacarpal (CMC) arthroplasty provides well-documented pain relief with preservation of thenar function for the treatment of basal joint arthritis. Nevertheless, a segment of the population undergoing this procedure will continue to have pain following surgery. Anecdotally, the senior authors hypothesize that unrecognized midcarpal arthritis is a major contributor to persistent pain after CMC arthroplasty. The prevalence of midcarpal arthritis in patients with basal joint arthritis is unknown. The goal of this study is to establish the prevalence of midcarpal arthritis in patients with CMC arthritis and/or STT (scaphotrapezotrapezoid) arthritis.

Materials and Methods: After obtaining Institutional Review Board approval, patients with basal joint arthritis were identified from a billing search using ICD-9 code 716.94. Hand radiographs were retrospectively reviewed and graded using the Eaton classification and Sodha classification for CMC arthritis. STT arthritis and midcarpal arthritis were graded using the Sodha classification for arthritis as follows: grade 1: no or nearly no arthrosis, grade 2: definite arthrosis but not severe, grade 3: severe arthrosis.

Results: 896 X-rays were reviewed. At the CMC joint, the average Eaton score was 3.14 ± 0.03 (mean ± SEM) and the average Sohda score was 2.51 ± 0.02. The prevalence of STT arthritis was 64%, and the mean Sohda score at the STT joint was 1.90 ± 0.03. The prevalence of midcarpal arthritis was 24%, and the mean Sohda score at the midcarpal joint was 1.30 ± 0.02.

Conclusions: The prevalence of midcarpal arthritis in patients with basal joint arthritis is 24%. The presence of two locations of arthritis may explain persistent hand and wrist pain in this population despite CMC arthroplasty. Clinically, these data will allow hand surgeons to educate patients with basal joint and midcarpal arthritis better regarding the possibility of incomplete pain relief following CMC arthroplasty.