Unilateral Shoulder Instability Research Articles

Latarjet procedure restores range of motion at 6 months postoperatively: a prospective cohort study using motion capture analysis

BackgroundThere is a common concern that range of motion (ROM) is negatively affected by the Latarjet procedure. We hypothesize that the Latarjet procedure results in full recuperation of ROM postoperatively and significantly improved patient reported outcome measures. MethodsPatient data were prospectively collected from a randomized controlled trial to analyze outcomes after open Latarjet procedure. Inclusion criteria involved a minimum follow-up of six months and unilateral shoulder instability. Study outcome was assessed by postoperative ROM at six months postoperatively and compared to the preoperative ROM of the ipsilateral shoulder as well as the ROM of the unaffected contralateral shoulder. All ROM measurements were performed utilizing a motion capture system to ensure consistent and reliable measurements. ResultsThe study included a total of 84 patients. ROM was measured in external rotation with the shoulder adducted (ER1), external rotation with the shoulder abducted 90 degrees (ER2), internal rotation with the arm abducted 90 degrees (IR2), and active forward elevation (AE). The average difference in ROM between the operated arm vs. the contralateral healthy arm at six months postoperatively was 3.4 degrees in ER1 (p=0.19), 4.2 degrees in ER2 (p=0.086), 2.2 degrees in IR2 (p=0.36), and 2.4 degrees in AE (p=0.045). Sub-analysis of patients with and without sling use revealed no significant difference in ROM between the operated shoulder and contralateral shoulder at six months in either group, with the exception of ER2 in the sling group. In this latter group, ROM was 71 degrees in the operated arm and 79 degrees in the contralateral arm (p=0.0094). Average preoperative pain score was 25.7 (21.4-30.1, 95%CI) vs. 13.0 postoperatively at six months (9.50-16.5, 95%CI) (p <0.00001). Average preoperative SANE instability was 42.9 (38.4-47.3, 95%CI) vs. 86.2 postoperatively at six months (83.6-88.7, 95%CI) (p <0.00001). Average preoperative Rowe score was 38.5 (34.3-42.7, 95%CI) vs. 84.3 at six postoperative months (81.1-87.4, 95%CI) (p<0.00001). ConclusionsLatarjet procedure performed for anterior instability utilizing a capsular repair result in complete ROM recovery in ER1, ER2, and IR2 at six months postoperatively, with only a slight discrepancy in active elevation. Sling use after the Latarjet procedure results in no benefit over postoperative recovery without the use of a sling. Sling use negatively affects the ROM in ER2, taking as reference the contralateral arm of the same patient, when compared to patients that did not use a sling postoperatively.

Bilateral shoulder proprioception deficit in unilateral anterior shoulder instability

Proprioception is an important element of shoulder dynamic stability. It has been shown to be affected in cases of capsular or labral injuries of the glenohumeral joint. Therefore, this study was conducted to investigate bilateral shoulder proprioception by active reproduction of joint position both in patients with post-traumatic recurrent unilateral shoulder instability and in normal healthy volunteers. We compared 41 patients, comprising 11 female and 30 male patients with an average age of 25.6 years (range, 18-39 years), with post-traumatic unilateral anterior shoulder instability with a control group of 27 healthy volunteers with no history of shoulder problems and with normal shoulder function during examination. All patients were examined using a high-accuracy computer-controlled electronic goniometer (Propriometer). The error of active reproduction of joint position (EARJP) was measured in abduction, flexion, external rotation, and internal rotation in both shoulders. We observed a significant deficit in the EARJP in the unstable shoulders within the instability group. Surprisingly, similar results were recorded for the contralateral, unaffected shoulders within this group of patients compared with the control group. Joint acuity increased with higher elevation of the arm position. Unilateral shoulder injuries, resulting in instability, affect proprioception in both shoulders, as demonstrated by an increased EARJP. This is the first report of unilateral shoulder instability coexisting with inferior proprioception in both shoulders.

Computed tomography osteoabsorptiometry for assessing the density distribution of subchondral bone as a measure of long-term mechanical stress in the “rugby shoulder”

Rugby is a collision sport with a high risk of shoulder injury. Although traumatic anterior shoulder instability is common, the long-term effects of rugby and joint instability on the shoulder have not been described; thus, this study assessed the effects of rugby itself, and joint instability, on the glenoid cavity. Both sides of the shoulders from 25 rugby players and 17 control patients with unilateral shoulder instability were prospectively evaluated by means of computed tomography osteoabsorptiometry, which represents the distribution of mineralization in subchondral bone plate (DMSB) as a marker of the long-term loading history of a joint. For the quantitative analysis, intergroup differences of maximum Hounsfield unit (HU) values in 7 areas on the glenoid were assessed in the uninjured intact shoulder to characterize the influence of rugby. Side-to-side differences of the HUs in each area were assessed in each participant to characterize the effects of shoulder instability. For the qualitative analysis, associations between the patterns of each DMSB and each group were assessed by means of correspondence analysis. All examined areas on the glenoid had a significantly higher HUs in rugby players. Shoulder instability affected the HUs in both groups. A qualitative analysis demonstrated that the maximum HU tended to be shifted more inferiorly in rugby players and in the unstable shoulders. Rugby affects the shoulder joint, regardless of any history of instability, suggesting that "rugby shoulder" tends to involve degenerative changes, such as osteoarthritis or labral tears.

Swim training as therapy of neurogenic induced unilateral shoulder instability in three horses

Swim training as therapy of neurogenic induced unilateral shoulder instability in three horses

Ultrasonic measurement of the anterior translation in the shoulder joint

A new method for measuring the anterior translation in the shoulder joint by dynamic ultrasound was evaluated. We placed a 3.5-MHz transducer on the shoulder anteriorly. By using 3 bony landmarks, we then measured the anterior translation of the humeral head with a force of 90 N applied posteriorly. We performed such measurements in 20 subjects with healthy shoulders and in 20 patients with unilateral shoulder instability. There was a mean translation of 1.9 mm in healthy shoulders and 4.9 mm in unstable shoulders (P<.01). The mean difference between the 2 sides in subjects with normal shoulders was 0.7 mm, whereas the mean difference in patients with instability was 2.8 mm (P<.01). The normal shoulders were examined by 2 examiners to determine the degree to which different examiners' measurements might vary. Although one examiner recorded higher values than the other, the new method seems suitable for measuring increased laxity in unstable shoulders.

Reflex muscle contraction in anterior shoulder instability

Reduced proprioception may contribute to recurrent anterior shoulder instability. Twelve patients with unilateral shoulder instability were investigated for evidence of deficient proprioception with an activated pneumatic cylinder and surface electromyography electrodes; the contralateral normal shoulder was used as a control. The latency between onset of movement and the detection of muscle contraction was used as an index of proprioception. No significant difference in muscle contraction latency was detected between the stable and unstable shoulders, suggesting that there was no significant defect in muscular reflex activity. This study does not support the use of proprioception-enhancing physiotherapy in the treatment of posttraumatic anterior shoulder instability.

The Roentgenographic Evaluation of Anterior Shoulder Instability

Retrospective evaluations of roentgenograms of 83 patients with unilateral shoulder instability were surveyed to evaluate the usefulness of various radiographic projections and to correlate the information with the osseous pathology associated with prior glenohumeral dislocation. The Hill-Sachs and the osseous Bankart defects were considered pathognomonic radiographic signs of glenohumeral joint instability. Based on history, physical examination, and examination under general anesthesia, patients were divided into three categories--(1) dislocation group, (2) subluxation group, and (3) combination group. Roentgen projections evaluated included the anteroposterior view with the humerus in internal and external rotation, axillary view, West Point view, Stryker notch, and Didiee view. The Hill-Sachs defect on the posterolateral aspect of the humeral head was best demonstrated on the combination of an internal rotation and a Stryker notch view. The osseous Bankart defect on the anteroinferior glenoid rim was best documented on the Didiee and West Point views. The external rotation and axillary view did not add significantly to the preoperative radiographic findings. In a patient with an unstable shoulder, a radiographic series that includes an internal rotation, a Stryker notch view, and either a West Point or a Didiee view would maximize the diagnostic yield per radiographic cost, time, and exposure.