The inferior capsular-shift procedure for multidirectional instability of the shoulder.

Thirty-eight patients (forty-three shoulders) who had disabling multidirectional instability of the shoulder were managed with an inferior capsular-shift procedure through an anterior approach. All of the patients were followed for a minimum of two years. The postoperative range of motion of the shoulders was well maintained. The mean forward elevation was 172 degrees; external rotation, 77 degrees; and internal rotation, to the level of the eighth thoracic vertebra. Four patients (four shoulders) had recurrence of symptomatic and disabling multidirectional instability, but thirty-nine (91 per cent) of the shoulders continued to function well with no instability. Nine patients (24 per cent) continued to have episodes of apprehension, which correlated with the residual inferior and posterior translations found at the postoperative physical examination. Thirty-four patients (thirty-nine shoulders) stated that they were subjectively satisfied with the status of the shoulder, but four patients, in whom the instability had recurred, were not satisfied. Thirty-seven (86 per cent) of the shoulders were judged to have been improved by the procedure, the initial postoperative stability had been maintained, and the result had not deteriorated with time. Six shoulders, however, including the four with recurrent instability, were thought by the patient to have deteriorated with the increased duration of follow-up. It was our experience that if non-operative treatment of multidirectional instability of the shoulder failed, the inferior capsular-shift procedure provided satisfactory objective and subjective results. Failures and recurrences of symptomatic instability occurred early in the postoperative period. There appeared to be no deterioration of the results with follow-up to seventy-one months.     

Prosthesis position in shoulder arthroplasty. A cadaver study of the humeral component

In six cadaver shoulder joints, the external rotation was measured applying a constant external torque to the humerus before and after insertion of a non-constrained shoulder joint prosthesis at different degrees of retroversion. At 35-45 degrees of retroversion there was no difference between the external rotation of the inserted prosthesis and the external rotation of the joint before arthroplasty.     

Thermal capsulorrhaphy in the treatment of multidirectional instability of the shoulder

The treatment of symptomatic multidirectional instability (MDI) of the shoulder has proven a challenge to orthopaedic surgeons. Patients who refuse activity modification often fail nonsurgical management, and traditional surgical approaches may trade the dysfunction of instability for that of decreased motion and possible future arthrosis. Recently, several methods of arthroscopic thermal capsulorrhaphy have gained popularity. Studies have shown that capsular shrinkage occurs due to the denaturation of type I collagen with maintenance of heat-stable intermolecular cross-links. Thermally treated tissues undergo a predictable healing response. The primary advantages of this procedure are the decreased surgical morbidity and ease of procedure compared with open capsular shift. Additionally, it may provide improved stability and decreased pain while maintaining range of motion. When radiofrequency treatment provides inadequate visualized capsular contracture, arthroscopic rotator interval closure can improve stability without resorting to an open procedure. While initial results in certain clinical series are promising, the long-term efficacy remains to be seen.     

The arterial vascularization of the humeral head. An anatomical study

In twenty-nine specimens from fresh cadavera, we performed an anatomical study of the arteries of the humeral head to determine their intraosseous distributions. A radiopaque suspension was injected into the anterior circumflex, posterior circumflex, suprascapular, thoracoacromial, or subscapular artery and then the specimens were dissected and were analyzed macroscopically, and radiographs were made in three mutually perpendicular projections. In addition, sixteen of the specimens were cut into four-millimeter slices and were studied microradiographically. The humeral head was shown to have been perfused by the anterolateral ascending branch of the anterior circumflex artery in all specimens. That vessel ran parallel to the lateral aspect of the tendon of the long head of the biceps and entered the humeral head where the proximal end of the intertubercular groove met the greater tuberosity. When the intraosseous (terminal) part of the anterolateral branch, the so-called arcuate artery, had been perfused, almost the entire epiphysis was radiopaque. The posterior circumflex artery vascularized only the posterior portion of the greater tuberosity and a small posteroinferior part of the head. Anastomoses between the different arteries were abundant, but vascularization of all of the humeral head was possible only through the anterolateral branch of the anterior circumflex artery.     

Evaluation of tibial component fixation in specimens retrieved at autopsy.

Fixation of the tibial component was evaluated in eight knees retrieved at autopsy by comparing their radiographs with measurements of micromovement between the component and the tibial plateau. Micromovement in the one cemented Miller-Galante and seven cementless Ortholoc components, which had been implanted for a range of 3 days to 57 months, was measured with linearly variable differential transducers under anteroposterior shear and axial compressive loads. Micromovement between the tibial component and the screws and between the tibial component and the bone after the screws were removed also was measured in the cementless specimens. Minimal micromovement in most of the implants suggests that the tibial components were well fixed. Micromovement between the tibial tray and the screws also was minimal in the cementless components. Removing the screws did not significantly affect micromovement, except in the specimen retrieved 3 days after surgery and in the specimen with a complete radiolucent line under the component. The cementless tibial components fixed with screws, pegs, and stem were as stable as the component secured with cement. Partial radiolucencies were not associated with greater micromotion than that of bone ingrown areas, but the component with complete radiolucency did have greater micromotion than that of all of the other specimens.     

Early failure of anterior bone block in multidirectional shoulder instability: a case report

We report the case of a 47-year-old female patient who developed predominantly anterior multidirectional glenohumeral instability. After rehabilitation, this patient was treated surgically with an anterior coracoid bone block using the Latarjet technique. The second postoperative day, the control scan revealed posterior glenohumeral dislocation. The patient underwent a second operation for a posterior iliac block. At last clinical follow-up (six years), the patient had normal shoulder motion; shoulder function was considered excellent using the clinical scores. We recall the pathogenic hypotheses explaining multidirectional shoulder instability and discuss the proposed treatments. This case illustrates the difficult diagnosis and therapeutic management of multidirectional instability. Under general anesthesia, examination showed that posterior laxity predominated while paradoxically, the patient presented predominantly anteromedial dislocations. This case is also exceptional by the development of posterior dislocation, an unusual postoperative complication after an anterior bone block; we describe the therapeutic options. In the event of multidirectional instability with bone injuries, we recommend a block in the direction of the instability. Preoperative examination under general anesthesia can be helpful in understanding the mechanism of residual postoperative instability, which would require complementary surgical stabilization.     

Prosthesis position in shoulder arthroplasty: A cadaver study of the humeral component

In six cadaver shoulder joints, the external rotation was measured applying a constant external torque to the humerus before and after insertion of a non-constrained shoulder joint prosthesis at different degrees of retroversion. At 35-45° of retroversion there was no difference between the external rotation of the inserted prosthesis and the external rotation of the joint before arthroplasty.     

Prosthesis position in shoulder arthroplasty: A cadaver study of the humeral component

In six cadaver shoulder joints, the external rotation was measured applying a constant external torque to the humerus before and after insertion of a non-constrained shoulder joint prosthesis at different degrees of retroversion. At 35-45° of retroversion there was no difference between the external rotation of the inserted prosthesis and the external rotation of the joint before arthroplasty.     

A longitudinal study of patients with multidirectional instability of the shoulder with seven- to ten-year follow-up

The purpose of our study was to evaluate the long-term outcomes of patients with multidirectional instability of the shoulder initially treated with rehabilitation exercises. Sixty-four patients were treated for atraumatic multidirectional instability of the shoulder between 1987 and 1990. Preliminary evaluation was performed 2 years after initiation of treatment, and final evaluation of the patients was performed at a mean of 8 years after initiation of treatment. At the preliminary evaluation, 5 patients were lost to follow-up. Of the remaining 59 patients, 20 had undergone surgical treatment for stabilization of their shoulder. Of the 39 nonsurgically treated patients, 19 continued to have significant pain, and 18 continued to have significant instability of their shoulder. Of the 59 patients, 28 subjectively rated their shoulder condition as better or much better after conservative treatment. At the final evaluation, 2 more patients were lost to follow-up, and 1 additional patient had had surgical treatment. Thus, of the 57 patients available for final follow-up, 36 had received nonsurgical care, and 21 had undergone surgical treatment. Of the 36 nonsurgically treated patients, 23 rated their shoulders as good or excellent with regard to pain, and 17 were good or excellent with regard to instability. By the modified Rowe grading scale, 5 of 36 patients had excellent results, and 12 had good results. The remaining 19 patients were rated as having poor results. Only 8 patients reported that their shoulders were free of all pain and instability. Overall, of the entire group of 57 patients evaluated between 7 and 10 years after initiation of care, 17 had a satisfactory outcome from nonsurgical management based on stability and Rowe scores, 23 had good or excellent results with regard to pain, and 20 subjectively rated their shoulders as good or excellent. This review revealed a relatively poor response to nonsurgical treatment of multidirectional instability in this population of young, athletic patients.     

Anatomic short-stem humeral component in total shoulder arthroplasty: a retrospective analysis

BackgroundTotal shoulder arthroplasty (TSA) can be performed with a short-stem (SS) press-fit humeral component or a traditional-length (TL) humeral stem. The purpose of this study was to report the results of patient who underwent TSA with a SS and compare these results to patients who underwent TSA with a TL humeral stem.MethodsAll patients at a single institution who underwent TSA with a SS component with a minimum 2-year follow-up were identified. Demographic information was recorded. Functional and radiographic outcomes were recorded. These patients were then matched to a control group who underwent TSA with TL humeral stem and the clinical and radiographic outcomes were compared.ResultsThere were no significant differences in all range of motion and radiographic outcomes at final follow-up (P > .05). There were no significant differences in the American Shoulder and Elbow Surgeons, Single Assessment Numerical Evaluation, and Simple Shoulder Test outcome measures. SS patients reported a significantly higher visual analog scale at final follow-up compared to TL (P = .040).ConclusionThe use of a SS in TSA demonstrated no difference in range of motion, radiographic outcomes, and American Shoulder and Elbow Surgeons, Single Assessment Numerical Evaluation, and Simple Shoulder Test scores compared to the traditional stem. SS patients had a higher visual analog scale than TL stem patients. Further study with longer term follow-up is warranted to evaluate the effect of bone adaptive changes and functional outcomes.Level of evidenceLevel III.     

The arthroscopic treatment of multidirectional shoulder instability: two-year results of a multiple suture technique

Nineteen consecutive shoulders in 19 patients were treated for multidirectional shoulder instability with an arthroscopic capsular shift. Indications for the procedure included complaints of pain, instability, or both that was unresponsive to a prescribed exercise program that stressed rotator cuff and scapular stabilizer strengthening. All patients had evidence of increased joint laxity on physical examination; 17 had a 2+ or greater sulcus test and 2 had 3+ laxity both anteriorly and posteriorly. Fourteen of the 19 patients were injured during athletic activity. All surgeries were performed in an outpatient setting. All the patients were evaluated at an average of 34 months postoperatively with a minimum follow-up of 25 months. Based on the outcome scale described by Tibone and Bradley, the average postoperative score was 91 out of a possible 100 with 13 excellent, 5 good, and 1 fair result. All but 1 of the athletes returned to their previous level of performance but none were elite throwers. One patient had recurrent anterior subluxations treated with a repeat arthroscopic capsular shift and was rated as good. The patient rated as fair had no improvement in her pain after surgery. One patient complained of a painful supraclavicular suture that resolved spontaneously. There were no neurovascular complications or infections. Visualization of intra-articular pathology was enhanced with the arthroscope and aided in the diagnosis of multidirectional instability. The described technique proved safe and effective in treating multidirectional instability and enabling athletes to return to their previous level of function.     

Evaluation of cementless acetabular component migration. An experimental study

Roentgenograms of two human cadaveric pelves with three implanted acetabular components were taken in anatomic, tilted, and rotated positions to determine their effect on the measurement of cup migration. The best landmark for measuring migration along a vertical axis was the distance between the center of the cup and the teardrop line. The best measurement for cup migration along an horizontal axis was the distance between the center of the cup and the vertical line through the teardrop. When the teardrop is not visible, one should use the distance between the bottom of the cup and the obturator line, and the distance between the center of the cup and Kohler's line. Guidelines for roentgenographic comparability are as follows: at 10% magnification, the variation in distance between the obturator line and the teardrop line should be less than 5 mm, and the distance between the middle of the sacroiliac line and the vertical line through the pubis should be less than 0.5 cm.     

Optimal positioning of the humeral component in the reverse shoulder prosthesis

Introduction

Total reverse shoulder arthroplasty is becoming more and more the standard therapeutic practice for glenohumeral arthropathy with massive lesions of the rotator cuff. The biomechanical principle of this prosthesis is represented by the reversion of the normal anatomy of the shoulder joint. This non-anatomical prosthesis leads to a medialization of the rotation centre of the glenohumeral joint and also to a distalization of the humeral head. All that causes a deltoid tension increasing so allowing a larger abduction of the arm. Main complications of the reverse shoulder prosthesis are due to the joint instability, the scapular notching and the wear of the polyethylene insert.

Purpose

The main goal of the present work is to study the effect of the positioning of the humeral component on the intrinsic stability of the reverse shoulder prosthesis. In particular, through finite element method simulations, the variation of the stability ratio of the shoulder joint has been calculated for both vertical and horizontal dislocating loads depending on the humeral stem version angle. Moreover, in order to estimate the wear of the polyethylene cup, some analyses have been developed to calculate the pressures on the polyethylene insert.

Results

The obtained results demonstrate the dislocation of a shoulder prosthesis and the wear of the polyethylene insert can be prevented or limited by conveniently varying the version angle of the humeral component.     

The effect of variation in definition on the diagnosis of multidirectional instability of the shoulder

BACKGROUND: There currently is a wide variation in the definition of multidirectional instability of the shoulder in the literature. The purpose of this study was to determine if these variations influence the distribution of the diagnoses in a cohort of patients with shoulder instability. METHODS: A cohort of 168 patients who underwent shoulder surgery for instability of any type was studied. Statistical analysis was performed in two steps. First, the instability of the shoulder in each patient was classified with the use of four existing systems, and the number of patients classified as having multidirectional instability was compared among the classification systems. Second, the definition of multidirectional instability was modified so that the result of laxity testing was the criterion for making the diagnosis, and the changes in the distribution of patients with a diagnosis of multidirectional instability were analyzed. RESULTS: Classification with the four existing systems resulted in significant differences in the number of patients diagnosed as having multidirectional instability, with two (1.2%), seven (4.2%), thirteen (7.7%), and fourteen patients (8.3%) so diagnosed (p < 0.05). Modification of the definition of multidirectional instability so that it was based on laxity testing resulted in a wide variation in the number of patients diagnosed as having multidirectional instability; these numbers ranged from fourteen (8.3%) to 139 (82.7%) (p < 0.05). CONCLUSIONS: This study demonstrated that variations in the criteria used for the diagnosis of multidirectional instability significantly affect the distribution of patients with that diagnosis. The use of laxity testing tends to result in an overestimation of the number of patients with this condition. This observation is important because the results of studies may vary if patients with traumatic instability are considered to have multidirectional instability on the basis of laxity testing. Investigators studying patients with multidirectional instability should carefully define the inclusion criteria that they used.     

A study of diagnostic reliability in inferior shoulder instability: Measurement of inferior humeral displacement using arthroscopy

Purpose: The purpose of this study was to define arthroscopic measurement of inferior humeral displacement, which allows an objectively estimated reduction of capsular volume using arthroscopic techniques. Type of Study: Prospective controlled study. Methods: Based on a 3-grade classification, inferior displacement caused by axial traction was measured arthroscopically at 15° of forward flexion and 70° of abduction and neutral rotation over the humeral head in 143 patients (146 shoulders) who underwent surgery consecutively; 99 shoulders because of recurrent dislocations and 47 because of pain in the shoulder. Results: Grades II and III were considered pathologic; grade I (from 0 to 1 cm) was only considered doubtfully positive or within physiologic values. Testing showed a specificity of 96.20%.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 3 (March), 2002: pp 287–291