Arthroscopic Findings After Traumatic Shoulder Instability in Patients Older Than 35 Years.

BACKGROUND: Shoulder instability in the older patient traditionally has received less attention in the literature than in the younger patient population. However, when traumatic dislocation does occur, these patients often still have frequent pain, disability, and even continued instability. PURPOSE: To characterize the pathoanatomy of traumatic anterior shoulder instability in the older patient population and to discuss the correlating symptoms that ultimately led to operative treatment. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients with a history of an initial traumatic anterior shoulder instability event occurring after the age of 35 years who underwent arthroscopic surgical intervention were prospectively enrolled. Exclusion criteria included posterior instability, major fractures of the shoulder girdle, and multidirectional instability. All patients initially underwent a period of nonoperative rehabilitation. Operative treatment was performed if a patient continued to have pain and/or instability. Operative reports and arthroscopic pictures were reviewed for pathoanatomical findings. RESULTS: A total of 27 patients (28 shoulders) met the inclusion criteria and were analyzed in this study (22 men and 5 women; mean age, 55 years; age range, 35-74 years). Surgical intervention was performed for recurrent instability in 7 patients, pain for 8 patients, and pain with instability for 13 patients. Arthroscopic findings demonstrated 18 rotator cuff tears (RCTs) (64.3%) and 18 Bankart lesions (64.3%). Nine patients had both an RCT combined with a Bankart lesion (32.1%). Three humeral avulsion of the glenohumeral ligament (HAGL) lesions (10.7%) and 2 anterior labral periosteal sleeve avulsion (ALPSA) lesions (7.1%) were found. All shoulders demonstrated Hill-Sachs lesions of various size and depth. CONCLUSION: Traumatic shoulder instability in the older patient may result in a wide array of pathologic findings as well as a diversity of clinical presentations. These findings suggest that the clinical diagnostician should maintain a high index of suspicion for RCT, Bankart lesions, and HAGL lesions in older patients who remain symptomatic after traumatic anterior shoulder instability.

Intra-articular distal femur fracture extending from an expanded femoral tunnel in an anterior cruciate ligament (ACL) reconstructed knee: a case report.

Anterior cruciate ligament (ACL) reconstruction is a popular surgery with overall good results. However, postoperative fracture is a serious, albeit, rare complication. Femoral tunnel lysis may cause a stress riser effect leading to distal femur fractures after ACL reconstruction. We report a case in which a patient who underwent ACL reconstruction surgery 18 months before a low-energy twisting mechanism suffered a distal femur fracture requiring open reduction internal fixation.

Musculoskeletal parameters of muscles crossing the shoulder and elbow and the effect of sarcomere length sample size on estimation of optimal muscle length.

BACKGROUND: Knowledge of musculoskeletal parameters is essential to understanding and modeling a muscle's force generating capability. A study of musculoskeletal parameters was conducted in two parts: (I) Empirical measurement of upper extremity musculoskeletal parameters. (II) Computational bootstrap simulation to examine statistical power of detecting optimal muscle length as a function of sarcomere length sample size and effect size. METHODS: Parameters were determined with a cadaver model. Sarcomere lengths were measured for 120 samples per muscle using laser diffraction and the mean sarcomere length used to estimate optimal muscle length. A bootstrap computational simulation was conducted to estimate variance in mean sarcomere length as a function of sample size. Statistical power for detecting optimal muscle length as a function of sample size and effect size was then determined. FINDINGS: Parameters are reported in tabular format. Power is 80% at approximately 85, 50, 40 and 25 samples for effect sizes of 0.5, 0.75, 1.0 and 1.5 mm respectively. INTERPRETATION: Musculoskeletal parameters for predicting muscle forces can be adequately measured in a cadaver model. Measurement of 40-60 sarcomere lengths per muscle is sufficient to calculate mean sarcomere length for estimating optimal muscle length with power of 80% for an effect size of 0.75-1.0 mm.