Three-Dimensional Analysis of Scapular Kinematics During Arm Elevation in Baseball Players With Scapular Dyskinesis: Comparison of Dominant and Nondominant Arms.

BACKGROUND: The knowledge of 3-dimensional scapular kinematics is essential for understanding the pathological lesions of the shoulder and elbow in throwing athletes. Many studies about alterations of the resting scapular position, dynamic scapular motion, or scapular dyskinesis (SD) have been conducted, yet none of them have identified a consistent pattern of altered scapular kinematics in throwing athletes. Hypothesis/Purpose: To analyze the 3-dimensional scapular kinematics of dominant and nondominant arms in baseball players with a pathological condition of the shoulder or elbow. STUDY DESIGN: Cross-sectional study. METHODS: Bilateral scapular positions, consisting of upward rotation (UR), superior translation (ST), internal rotation (IR), protraction (PRO), and anterior tilting (AT) with an arm at rest and at 150° forward elevation, were measured among 319 baseball players with SD using 3-dimensional computed tomography. Angular values of scapula were compared between dominant and nondominant arms with statistical analysis. LEVEL OF EVIDENCE: Level III, diagnostic study. RESULTS: The scapular position of dominant arms showed significantly more AT, less ST at rest and more UR and IR and less ST, PRO, and AT at 150° full forward elevation compared with the nondominant arms. The magnitude of mean change of UR, IR, PRO, and AT during arm elevation increased significantly between the paired arms (P value: UR, ST, PRO, and AT: <.001 and IR: .001). CONCLUSION: When compared with the nondominant arms, UR, AT, and PRO with the arm at 150° forward elevation of dominant symptomatic arms in baseball players tilted toward positive compensation, whereas IR altered toward negative decompensation. In addition, the angular increment of the scapula increased significantly in dominant symptomatic arms compared with the nondominant arms.

Prevalence and clinical outcomes of heterotopic ossification after ulnar collateral ligament reconstruction.

BACKGROUND: Ulnar collateral ligament (UCL) reconstruction has become increasingly popular in elite athletes. However, the prevalence of heterotopic ossification (HO) formation after UCL reconstruction has not yet been reported. We sought to determine the prevalence of HO formation after UCL reconstruction and the clinical outcomes following HO treatment. MATERIALS AND METHODS: From October 2005 to April 2014, 179 patients underwent primary UCL reconstruction. Of the 179 patients, 161 with a minimum of 2 years of follow-up were retrospectively reviewed to evaluate HO formation and clinical outcomes. RESULTS: Among 161 patients, HO was detected in 8 cases (5%). Of these 8 patients, 2 were asymptomatic and another 2 complained about transient ulnar neuropathy. The remaining 4 patients had pain; 2 were treated with open excision, and 1 underwent arthroscopic excision. The odds of HO in patients in whom transient ulnar neuropathy develops after UCL reconstruction are 6 times higher than those without transient ulnar neuropathy (odds ratio, 5.957; 95% confidence level, P = .04). Of the 8 patients, 7 returned to the same level or a higher level of competition. HO was found, on average, 5 months (range, 3-9 months) after UCL reconstruction. CONCLUSION: The prevalence of HO formation was approximately 5% after UCL reconstruction and increased with transient ulnar neuropathy. After UCL reconstruction, the surgeon should carefully observe HO formation, especially in the early stages after the operation. With appropriate treatment, the clinical outcomes of HO treatment after UCL reconstruction are favorable.

Does Lordotic Angle of Cage Determine Lumbar Lordosis in Lumbar Interbody Fusion?

STUDY DESIGN: Retrospective, radiological analysis. OBJECTIVE: To determine that 15° lordotic angle cages create higher lumbar lordosis in open transforaminal lumbar interbody fusion (TLIF) than 4° and 8° cages. SUMMARY OF BACKGROUND DATA: Restoration of lumbar lordosis is important to obtain good outcome after lumbar fusion surgery. Various shapes and angles of cages in interbody fusion have been used; however, it is not proved that lordotic angle of cages determine lumbar lordosis. METHODS: Sixty-seven patients were evaluated after TLIF using 15° cages and screw instrumentation. For comparison, TLIF using 4° lordotic angle cages in 65 patients and 8° cages in 49 patients were analyzed. Lumbar lordosis angles, segmental lordosis angles, disc height, and bony union rate were measured on the radiographs. RESULTS: The lumbar lordosis was 31.1° preoperatively, improved to 42.9° postoperatively, and decreased to 36.4° at the last follow-up in the 15° group. It was 35.8° before surgery, corrected to 41.5° after surgery, and changed to 33.6° at the last follow-up in the 4° group. In the 8° group, it was 32.7° preoperatively, improved to 39.1° postoperatively, and decreased to 34.5° at the last follow-up. These changes showed statistical significances (P < 0.001). The segmental lordosis at L4-5 was 6.6° before surgery, 13.1° after surgery, and 9.8° at the last follow-up in the 15° group. It was 6.9°, 9.5°, and 6.2° in the 4° group and 6.7°, 9.8°, and 8.1° in the 8° group, respectively (P < 0.001). The disc height restoration was better in the 15° group than in the 4° and 8° groups (P < 0.001). Bony union rate was not significant among the three groups (P = 0.087). CONCLUSION: The lordotic angle of the cages determined restoration of lumbar lordosis after TLIF. Cages with sufficient lordotic angle showed better restoration of lumbar lordosis and prevention of loss of correction. LEVEL OF EVIDENCE: 4.