Summary

Dynamometric testing of index finger distal phalanx flexion strength endurance reveals lower maximum and average strength in the lacertus-affected side at diagnosis and maximum and average strength recovery after surgery. Dynamometric testing of index finger distal phalanx flexion strength might have diagnostic and recovery assessment potential for lacertus syndrome in recreational athletes.

Abstract

Objective

To assess the index finger distal phalanx flexion strength endurance with a dynamometer in recreational athletes with lacertus syndrome.

Methods

A retrospective study of prospectively collected data was conducted on recreational athletes diagnosed with lacertus syndrome from April 2023 to August 2024. Patients were included if they met the following criteria: (1) had weakness in the flexor carpi radialis (FCR), flexor pollicis longus (FPL), and flexor digitorum profundus to the index finger (FDP II); (2) had a positive provocative sensory testing (scratch collapse test); and (3) had pain and/or positive Tinel's test at the level of the nerve compression (elbow). Patients were excluded if: (1) had bilateral symptoms; or (2) had any additional injury that limited their ability to perform the dynamometric testing. Bilateral index fingers' distal phalanx flexion strength was assessed for 30 seconds with a dynamometer (Tindeq®, BLIMS AS, Norway) with full forearm pronation at diagnosis and two weeks after surgery. Patient demographic data, sports type, Disabilities of the Arm, Shoulder and Hand (DASH) score, maximum strength, and average strength during the 30-second dynamometric test were recorded. Patient data was summarized using means and standard deviations. Healthy (control) and lacertus-affected index finger distal phalanx flexion strength during the 30-second dynamometric testing results were compared using paired mean differences (MD) and expressed as 95% confidence intervals (CI).

Results

Five patients were included in the final assessment, five recreational athletes (4 males and 1 female; weightlifting 3, Pilates 1, cycling 1), with a mean age of 35.2 years (range 28-53), and a mean DASH score of 26.63 at diagnosis. The mean healthy index finger maximum strength was 9.08 ± 2.29 Kg, and average strength was 5.92 ± 1.6 Kg during the 30-second test, while the mean lacertus-affected index finger maximum strength was 7.27 ± 2.10 Kg and average strength was 4.74 ± 1.44 Kg during the 30-second test. Patients showed lower maximum strength and average strength during the 30-second dynamometric testing in the lacertus-affected index finger at diagnosis (95% CI [0.11, 3.5] and [-0.33, 2.69], respectively). Two patients were assessed two weeks after surgery, showing increased maximum and average strength on the operated side compared to preoperative values (MD 0.82 Kg, range 0.79-0.84; and MD 0.99 Kg, range 0.51-1.48, respectively).

Conclusions

Dynamometric testing of index finger distal phalanx flexion strength endurance reveals lower maximum and average strength in the lacertus-affected side at diagnosis and maximum and average strength recovery after surgery. Dynamometric testing of index finger distal phalanx flexion strength endurance might have diagnostic and recovery assessment potential for lacertus syndrome in recreational athletes.