J Wrist Surg 2015; 04 - A012
DOI: 10.1055/s-0035-1567904

Does Pain and Loss of Function Correlate with Joint Morphology in CMC OA?

J.J. Trey Crisco 1, T. Patel 1, D. C. Moore 1, A.L. Ladd 2, A-P.C. Wiess 1
  • 1Department of Orthopaedics, Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, Rhode Island
  • 2Robert A. Chase Hand & Upper Limb Center, Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, California

Introduction: Thumb carpometacarpal (CMC) osteoarthritis (OA) is a widespread, disabling disease of undetermined etiology that is far more prevalent in women than in men. Loss of thumb function alone imparts 40–50% impairment to the upper extremity due to its central role in nearly all grasping and handling tasks. Decreased function is well associated with pain, but the source and mechanism of OA pain remains to be clearly identified. The aim of this cross-sectional study was to examine the association between thumb pain and CMC joint morphology.

Methods: Subjects with no thumb pain (n = 46; 18–75 years) and patients with CMC pain (n = 92; 45–75 years) but no gross radiographic changes were recruited with institutional review board (IRB) approval as part of a larger study of thumb OA. Pain and loss of function were self-reported using the Patient-Rated Wrist and Hand Evaluation (PRWHE) and Australian/Canadian OA Hand Index (AUSCAN) instruments. X-ray images were graded with the Eaton classification, for the presence of joint narrowing and the percentage of subluxation. Computed tomography (CT) images of the thumb in a splinted neutral position were acquired and then analyzed using established algorithms for measures of joint space, contact area, contact location, and joint curvature. Differences among groups were compared using one-way analysis of variance (ANOVA) and association between morphology and pain score were assessed with linear regression.

Results: PRWHE and AUSCAN subcategories were each highly linearly correlated with PRWHE Total, so only PRWHE Total was assessed against joint morphological measures. Increasing subluxation was associated with increasing PRWHE Total (p = 0.0015, R2 = –0.079). PWRHE Total scores did not differ among X-ray grades (0: n = 62, 1: n = 26, and 2: n = 1) or when subjects were grouped by joint space narrowing (0, n = 55; and 1, n = 34). However, CT-derived joint space significantly decreased in patients who reported higher values of PRWHE Total (p < 0.0001, R2 = 0.1379). By group, joint space was significantly (p < 0.05) greater in the young male and female subjects than in the arthritic male and female patients by 0.5 mm and 0.4 mm, respectively. Joint spacing in the older men was similar that in to the young subjects, while the joint spacing in the older women was more similar to that in the arthritic subjects.

Conclusion: Loss of CT-derived joint spacing on the order of tenths of mm was observed in the OA populations, and this subtle loss in joint spacing was associated with an increase in self-reported pain severity and loss of function.

Acknowledgments

NIH/NIAMS AR059185.

Conflict of Interest

No authors possess a potential conflict of interest with findings of this study.