A Biomechanical Evaluation of an Anatomical Coracoclavicular Ligament Reconstruction

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/cm 2 ), 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. Keywords: shoulder acromioclavicular joint biomechanics surgery anatomical reconstruction