Objective To study the biomechanical differences of the first carpometacarpal joint stability by using different reconstruction methods so as to provide theoretical basis for the clinical choice of reconstruction method. Methods The upper limb specimens were selected from 12 fresh adult cadavers, which had no fracture, bone disease, dislocation of wrist joint, deformity, degeneration, or ligament injury on the anteroposterior and lateral X-ray films. The specimens were randomly divided into 5 groups: normal group, injury group, palmar carpometacarpal ligaments reconstruction group, dorsal carpometacarpal ligaments reconstruction group, and palmar and dorsal carpometacarpal ligaments reconstruction group. Three normal specimens were used as normal group, and then were made of the first carpometacarpal joint dislocation models (injury group); after the first carpometacarpal joint dislocation was established in the other 9 specimens; the volar ligament, dorsal ligament, and volar-dorsal ligaments were reconstructed with Eaton-Little method, Yin Weitian method, and the above two methods in 3 construction groups. The biomechanical test was done to obtain the load-displacement curve and to calculate the elastic modulus. Results During biomechanical test, ligament rupture and loosening of Kirschner wire occurred in 1 case of injury group and palmar carpometacarpal ligaments reconstruction group; no slipping was observed. The elastic modulus values were (11.61±0.20), (5.39±0.12), (6.33±0.10), (7.12±0.08), and (8.30±0.10) MPa in normal group, injury group, palmar carpometacarpal ligaments reconstruction group, dorsal carpometacarpal ligaments reconstruction group, and palmar and dorsal carpometacarpal ligaments reconstruction group respectively, showing significant differences among groups (P<0.05). Conclusion Volar ligament reconstruction, dorsal ligament reconstruction, and volar-dorsal ligament reconstruction all can greatly improve the stability of the first carpometacarpal joint. And the effect of volar-dorsal ligament reconstruction is the best, but the stability can not restore to normal.
Objective To investigate the effectiveness of arthroscopic long head of biceps tendon (LHBT) transposition combined with Swivelock anchor double fixation in treatment of massive and irreparable rotator cuff tears. Methods Between June 2019 and November 2021, 25 patients with massive and irreparable rotator cuff tears were treated by arthroscopic LHBT transposition combined with Swivelock anchor double fixation. There were 12 males and 13 females. The age ranged from 47 to 74 years (mean, 62.4 years). The disease duration ranged from 1 to 62 months (median, 7 months). The rotator cuff tears were classified as Hamada grade 2 in 25 cases and Goutallier grade 1 in 2 cases, grade 2 in 22 cases, and grade 3 in 1 case. Pre- and post-operative shoulder range of motion (ROM), visual analogue scale (VAS) score, University of California Los Angeles (UCLA) score, and Constant-Murley score were recorded. Postoperative complications were observed. The reconstructed tissue integrity was confirmed by MRI. Results All operations were successfully completed. The operation time was 120-330 minutes (mean, 189.6 minutes). All incisions healed by first intention. All patients were followed up 10-36 months (mean, 22.0 months). At last follow-up, the ROM in forward flexion, abduction, and external rotation, VAS score, UCLA score, and Constant-Murley score were superior to those before operation, and the differences were significant (P<0.05). According to UCLA scoring standard, shoulder joint function was rated as excellent in 5 cases, good in 18 cases, and poor in 2 cases, with an excellent and good rate of 92.0%. No other complications occurred except shoulder joint adhesion in 2 cases. At last follow-up, MRI examination showed no retear of rotator cuff, and LHBT was intact. Conclusion For massive and irreparable rotator cuff tears, arthroscopic LHBT transposition combined with Swivelock anchor double fixation can increase the force of pressing the humeral head, effectively relieve the pain, improve the ROM of joints, maximize the recovery of shoulder function, and do not increase the number of anchor nails.