Table 2 Summary of the main aspects of the cited biomechanical studies

Lee et al. [3]

To compare biomechanical properties of native CC ligaments versus tendon graft reconstructions versus other methods

11 human cadaveric shoulders were tested to failure to compare the biomechanical properties of the native CC ligaments, CA ligament transfer, Mersilene suture repair, Mersilene tape repair, and tendon graft reconstructions with gracilis, semitendinosus, and long toe extensor

Reconstructions with semitendinosus, gracilis, or long toe extensor tendon grafts had superior initial biomechanical properties compared with CA ligament transfer; failure strengths were as strong as those of the native CC ligaments

Tendon graft reconstruction may be an alternative to CA ligament transfer and may provide a permanent biologic reconstruction with superior initial biomechanical properties

Michlitsch et al. [16]

To compare the biomechanical characteristics of a modified Weaver–Dunn reconstruction and an ACJ reconstruction with free-tissue graft for reconstruction of both CC and AC ligaments

6 pairs of cadaveric shoulders had a modified Weaver–Dunn reconstruction on 1 side and the contralateral side had a graft reconstruction of CC and AC ligaments. Load-to-failure was performed

AP and superior-inferior (SI) translation of the ACJ reconstruction was significantly less than that of the modified Weaver–Dunn under all loading conditions

ACJ reconstruction with free-tissue graft for both CC and AC ligaments demonstrates initial stability significantly better than a modified Weaver–Dunn and similar to that of intact specimens

Grutter et al. [17]

To compare the modified Weaver–Dunn procedure, the anatomical AC reconstruction using palmaris longus graft, and anatomical AC reconstruction using flexor carpi radialis graft

The native ACJ in 6 fresh-frozen cadaveric upper extremities was stressed to failure under tension in the coronal plane. Each repair was stressed to failure

Load to failure for native ACJ complex was 815 N, modified Weaver–Dunn 483 N, anatomical AC reconstruction with palmaris longus 326 N, and anatomical AC reconstruction with flexor carpi radialis 774 N

Anatomical AC reconstruction with a flexor carpi radialis tendon graft re-creates the tensile strength of the native ACJ complex and is superior to a modified Weaver–Dunn repair

Dawson et al. [20]

To compare the stability of the ACJ and biomechanical characteristics of the ACJ capsule and CC ligaments

AP and SI ACJ translations were quantified in 6 cadaver matched pairs. Either the ACJ capsule or CC ligaments were transected, and measurements were repeated. The biomechanics of the remaining ACJ capsule or CC ligaments were compared

Significant increases in AP translation with the cut ACJ capsule, and significant increases in SI translation with the cut CC ligaments

The ACJ capsule contributes significantly to the ACJ stability, especially in the AP plane

Deshmukh et al. [30]

To determine biomechanical basis for augmenting the Weaver–Dunn with supplemental fixation

Native ACJ motion was measured. AC and CC ligaments were cut, and 1 of 6 reconstructions was performed: Weaver–Dunn, suture cerclage, and 4 different suture anchors. ACJ motion was reassessed, cyclic loading test was performed, and failure load was recorded

Weaver–Dunn reconstructions failed at a lower load. Reconstruction using augmentative fixation allowed less AC motion than Weaver–Dunn reconstruction, but more motion than the native ligaments

Although none of the augmentative methods tested restored ACJ stability to normal, all proved superior to the Weaver–Dunn reconstruction alone.

Abat et al. [33]

To evaluate the vertical biomechanical behavior of two techniques for the anatomical repair of the CC ligaments

18 human cadaveric shoulders. 3 groups were formed–group I, control; group II, double tunnel in clavicle and 1 in coracoid (with two CC suspension devices); group III, repair in ‘V’ configuration with two tunnels in clavicle and one in coracoid (with one CC suspension device). The force required for failure was analyzed

Comparison of the three groups did not find any significant difference despite the loss of resistance presented by group III

Anatomical repair of CC ligaments with a double system (double tunnel in the clavicle and in the coracoid) permits vertical translation that is more like that of the ACJ