gms | German Medical Science

Introduction: Temporary or long-lasting loss of grip force after open carpal tunnel release (CTR) in carpal tunnel syndrome (CTS) patients is well known and caused by changes in biomechanical conditions through sectioning of the transverse carpal ligament. We hypothesize to find predicting factors for loss of grip strength.

Methods: We performed dynamometer testing of overall hand grip, tip pinch and key pinch grip prior and three months after open CTR in 354 CTS subjects. Changes in these three main variables related to pre-operative grip, tip pinch and key pinch forces as well as pain score (VAS-score adapted from 0-100) were analyzed for significant results (t-test, Pearson and Spearman correlations, descriptive statistics; 2-tailed p=.05).

Results: Overall hand grip force decreased significantly by 4.8 % (p=.002), whereas key pinch and tip pinch increased significantly by 5.4 and 8.3 % (p=.000). Further investigation showed, that subjects with a strong grip prior to the operation seem to lose more strength three months after operation than subjects with average strength results (Spearman -.516; p=.000; Pearson -.517; p=.000; significant at p=.01). Key pinch and tip pinch showed similar results with high force subjects losing more strength three-months post-CTR (key pinch: Spearman -.422, p=.000; Pearson -.424, p=.000; tip pinch: Spearman -.439, p=.000; Pearson -.506, p=.000; significant at p=.01).

Discussion: Open release of the TCL is an excellent method for symptom relief in CTS patients. Nevertheless, post-operative weakness can be long lasting. Patients with strong grip forces and only recent symptoms without signs of nerve injury or muscle atrophy could profit from this study by enrolling into prolonged conservative therapy instead of immediate surgical transversal carpal ligament release. Knowledge about predictors of open carpal tunnel release outcome can provide realistic post-operative expectations to assure a more satisfied patient and surgeon.