A Biomechanical Evaluation of an Anatomical Coracoclavicular Ligament Reconstruction

Abstract

Background Despite numerous surgical techniques described, there have been few studies evaluating the biomechanical performance of acromioclavicular joint reconstructions. Purpose To compare a newly developed anatomical coracoclavicular ligament reconstruction with a modified Weaver-Dunn procedure and a recently described arthroscopic method using ultrastrong nonabsorbable suture material. Study Design Controlled laboratory study. Methods Forty-two fresh-frozen cadaveric shoulders (72.8 ± 13.4 years) were randomly assigned to 3 groups: arthroscopic reconstruction, anatomical coracoclavicular reconstruction, and a modified Weaver-Dunn procedure. Bone mineral density was obtained on all specimens. Specimens were tested to 70 N in 3 directions, anterior, posterior, and superior, comparing the intact to the reconstructed states. Superior cyclic loading at 70 N for 3000 cycles was then performed at a rate of 1 Hz, followed by a load to failure test (120 mm/min) to simulate physiologic states at the acromioclavicular joint. Results In comparison to the intact state, the modified Weaver-Dunn procedure had significantly (P <. 05) greater laxity than the anatomical coracoclavicular reconstruction or the arthroscopic reconstruction. There were no significant differences in bone mineral density (g/cm2), load to failure, superior migration over 3000 cycles, or superior displacement. The anatomical coracoclavicular reconstruction had significantly less (P <. 05) anterior and posterior translation than the modified Weaver-Dunn procedure. The arthroscopic reconstruction yielded significantly less anterior displacement (P <. 05) than the modified Weaver-Dunn procedure. Conclusion The anatomical coracoclavicular reconstruction has less anterior and posterior translation and more closely approximates the intact state, restoring function of the acromioclavicular and coracoclavicular ligaments. Clinical Relevance A more anatomical reconstruction using a free tendon graft of both the trapezoid and conoid ligaments may provide a stronger, permanent biologic solution for dislocation of the acromioclavicular joint. This reconstruction may minimize recurrent subluxation and residual pain and permit earlier rehabilitation.