• Jieying Xu, Fok Chuan Yong, Celestine Wenxian Lim, Kevin Jian Hao Wong, and Lam Chuan Teoh.
• Tan Tock Seng Hospital, 11 Jln Tan Tock Seng, Singapore, 308433, Singapore. Jieying.xu@mohh.com.sg.
• Arch Orthop Trauma Surg. 2022 Apr 1; 142 (4): 701-705.

IntroductionArthrodesis of the proximal interphalangeal (PIP) joint at 40° angle has been proposed by many authors. A smaller angle of arthrodesis results in weaker grip strength of the hand from the quadriga effect. However, arthrodesis at 40° compromises other aspects of hand function including poor aesthetic appearance. This paper aims to quantify the decrease in grip strength at 40°, 20°, and 0° of arthrodesis.Materials And MethodsGrip strengths of the hand were measured using a BASELINE dynamometer at settings II, III, and IV. Baseline grip strength of the subjects were first measured without wearing a splint. Thereafter, subjects wore thermoplastic splints to simulate arthrodesis of the middle and ring finger PIP joint at 40°, 20°, and 0°, and grip strengths were measured again. The grip strength of the hand with simulated arthrodesis was then calculated as a ratio of the baseline.ResultsThere were 50 subjects yielding 100 sets of results. The results show that average grip strength ratio of the hand decreases progressively from 40° and 20° and to 0° of arthrodesis for both the middle and ring finger. However, the difference in grip strength ratio between 40° and 20° of arthrodesis was minimal. Simulated arthrodesis of the middle finger affected the grip strength ratio more than arthrodesis of the ring finger, and compromised gripping of a smaller handle more than a wider one.ConclusionThe decrease in grip strength from 40° to 20° simulated fusion of PIP joint was minimal. Therefore, in so far as grip strength loss is concerned, arthrodesis of the PIP joint at an angle less than 40° can be considered for patients with individual functional and aesthetic concerns.© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

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