BASEBALL PLAYERS DIAGNOSED WITH ULNAR COLLATERAL LIGAMENT TEARS DEMONSTRATE GREATER SIDE TO SIDE DIFFERENCES IN PASSIVE GLENOHUMERAL ABDUCTION RANGE OF MOTION COMPARED TO HEALTHY CONTROLS.

BACKGROUND: Numerous studies have shown that baseball players develop range of motion adaptations in their throwing arm. While some of these shoulder range of motion adaptations can lead to greater throwing velocity, excessive changes in shoulder range of motion can increase the risk of injury to the ulnar collateral ligament (UCL). PURPOSE/HYPOTHESES: The purpose of this study was to compare the passive GH-ABD ROM measures of baseball players with a diagnosed UCL tear (UCL group) to a group of age, activity, and position matched healthy controls (CONT group). The primary hypothesis was that baseball players with an UCL tear would have a greater loss of passive glenohumeral abduction range of motion in their throwing shoulder than healthy controls. A secondary hypothesis was that baseball players with an UCL tear would demonstrate similar glenohumeral abduction range of motion in their non-throwing arm and increased side-to-side glenohumeral abduction differences compared to the healthy cohort. STUDY DESIGN: Retrospective prospective case-control study. RESULTS: The UCL group had significantly greater glenohumeral abduction range of motion on their throwing shoulder (132.5 °±8.3 °) than the CONT group (120.19 °±11.2 °, p = 0.000). Similarly, the UCL group had increased glenohumeral abduction range of motion on their non-throwing shoulder (141.2 °±9.5 °) compared to the CONT group (124.1 °±11.4 °, p = 0.000). Additionally, the UCL group had a greater glenohumeral abduction difference (-8.7 °±8.4 °) than the CONT group (-3.8 °±7.7 °, p = 0.001). CONCLUSION: In contrast to the original hypotheses, high school and collegiate baseball players that sustained an UCL injury presented with greater glenohumeral abduction range of motion in both their throwing and non-throwing shoulders compared to healthy controls. However, the finding of greater side-to-side glenohumeral abduction range of motion deficits in the UCL group when compared to the matched healthy controls confirms the secondary hypothesis. LEVEL OF EVIDENCE: Level 3.

Participants at three months post-operative anterior cruciate ligament reconstruction (ACL-R) demonstrate differences in lower extremity energy absorption contribution and quadriceps strength compared to healthy controls.

BACKGROUND: The purpose of this study was to compare hip and knee energy absorption contribution (EAC) during a double limb squat (DLS) and quadriceps strength in patients three months post-operative ACL-R versus matched healthy controls. METHODS: Twenty-four ACL-R participants (Age = 15.5 ±â€¯1.3 yrs; Ht = 1.66 ±â€¯.07 m; Mass = 66.3 ±â€¯15.5 kg) were compared to 24 age, sex, limb, and activity-matched healthy controls (Age = 15.5 ±â€¯1.2 yrs; Ht = 1.65 ±â€¯.08 m; Mass = 59.0 ±â€¯9.8 kg). Lower extremity biomechanical data was collected at three months post-operative ACL-R during five consecutive DLS. EAC was calculated during DLS descent. Isokinetic quadriceps strength was collected at 60°/s. Normalized quadriceps peak torque (QUADS) was averaged across five trials. Independent t-tests examined differences in group hip and knee EAC during each task. Separate Pearson product-moment correlations examined the relationship between QUADS and hip and knee EAC during the DLS. RESULTS: ACL-R demonstrated greater injured limb hip EAC (46.4 ±â€¯16.0) than Healthy (31.7 ±â€¯11.0) during a DLS (p = 0.001). ACL-R demonstrated less injured limb knee EAC (42.7 ±â€¯14.6) than Healthy (60.6 ±â€¯8.9) during DLS (p < 0.001). No differences were seen between uninjured limb hip (ACL-R = 0.0 ±â€¯14.2; Healthy = 33.4 ±â€¯9.1, p = 0.629) or knee (ACL-R = 56.9 ±â€¯15.6; Healthy = 59.1 ±â€¯9.8, p = 0.561) EAC and matched limbs. ACL-R injured limb QUADS was decreased compared to Healthy (ACL-R = 1.1 ±â€¯0.5; Healthy = 2.0 ±â€¯0.5, p < 0.001). No differences were seen in QUADS on the uninjured and matched limbs (ACL-R = 2.0 ±â€¯0.6; Healthy = 1.9 ±â€¯0.5, p = 0.894). There was a weak, negative correlation between injured limb QUADS and hip EAC (r = -0.471, p = 0.001) and moderate, positive correlation between injured limb QUADS and knee EAC (r = 0.615, p < 0.001). CONCLUSIONS: ACL-R participants demonstrate different eccentric loading strategies during a DLS at three months postoperative compared to matched healthy controls.