Biomechanical Evaluation of Opponensplasty for Low Median Palsy: A Cadaver Study

Thumb pronation efficacy of Camitz tendon transfer with insertion on the ulnar capsule of the metacarpophalangeal joint: a cadaver study

Several studies have indicated that Camitz transfer for severe carpal tunnel does not adequately restore thumb opposition. The aim of this study was to determine whether modification of the distal insertion of the transferred palmaris longus tendon could provide more effective opposition. We used 12 fresh-frozen upper extremity specimens. For spatial analysis, we used a three-dimensional motion-tracking device. At 0 N and 5 N of traction force, the pronation angle was significantly larger for the modified procedure than for the conventional procedure. There was no significant difference in the palmar abduction angle between the two groups. The modified palmaris longus tendon insertion on the ulnar side of the thumb metacarpophalangeal joint provides more effective thumb pronation than conventional Camitz opponensplasty in a cadaver model.    .

Thumb Pronation Angle in Thumb Opposition Evaluated by the Nail Tip Angle of Thumb-Ring Finger Opposition

BACKGROUND

This study aimed to devise the method for the evaluation of the thumb pronation angle and calculate its reference value.

METHODS

The study was conducted from October 2021 to March 2022, and 600 hands of 300 healthy volunteers were included in this study. The participants were divided into 6 age groups with 50 participants each. In study 1, 12 participants from group 1 were randomly selected, which included 6 male and 6 female participants. We measured the thumb pronation angle using FASTRAK system and the nail tip angle of thumb-ring finger opposition (T-R angle) and also evaluated the relation between them. In study 2, we measured the T-R angle of 600 hands of 300 healthy volunteers. The T-R angle mean (SD) and 95% confidence interval (CI) of each age group were calculated as reference values.

RESULTS

The thumb pronation angle was correlated with the T-R angle. The T-R angle mean (SD) and 95% CI of the 6 groups were as follows: group 1, 142.5° (12.4) and 117.7 to 167.3; group 2, 139.9° (10.1) and 119.7 to 160.1; group 3, 142.3° (9.7) and 122.9 to 160.5; group 4, 140.2° (12.6) and 115.0 to 165.4; group 5, 138.3° (11.9) and 114.5 to 162.1; and group 6, 135.4° (13.0) and 109.4 to 161.4. The 95% CI tended to decrease with an increasing age.

CONCLUSIONS

The T-R angle was a suitable evaluation method for the thumb pronation angle, and it should be evaluated by age groups.

Neurostimulation in severe carpal tunnel release: A more precise technique for opponensplasty decision-making

OBJECTIVES

In this study, we aimed to investigate the relationship between intraoperative thenar muscle neurostimulation responses and postoperative thumb function recovery in patients with severe carpal tunnel syndrome (CTS).

PATIENTS AND METHODS

Between January 2019 and December 2021, a total of 21 severe CTS cases in 20 patients (7 males, 13 females; mean age: 56.3±19.3 years; range, 52 to 76 years) based on clinical and electrophysiological findings were retrospectively analyzed. The median nerve motor branch (MNMB) was stimulated intraoperatively with a nerve stimulator. The patients were divided into two groups according to contraction response on abductor pollicis brevis (APB) muscle: Group C (contractile, n=13) and Group NR (non-responsive, n=7) with and without muscular contraction. The Levine Functional Severity Scale (LFSS) was used to measure the functional status of CTS patients. The Manual Muscle Testing (MMT) was used to assess muscle strength. Clinical outcomes were compared between the groups at one year of follow-up.

RESULTS

The mean total preoperative LFSS score was significantly higher in Group NR than in Group C (p=0.010). The mean postoperative MMT score was significantly higher in Group C than in Group NR (p<0.001). There was no positive result in pick-up, button fastening, and needle pinch tests in Group NR (p<0.001). However, there were significant improvements in postoperative LFSS scores in Group C (p<0.05), while the scores remained unchanged in Group NR (p>0.05).

CONCLUSION

Direct stimulation of the median nerve motor branch and observation of contraction response on APB muscle can be used to predict clinical recovery and facilitates making the decision for opponensplasty in severe CTS.