Capsulolabral augmentation increases glenohumeral stability in the cadaver shoulder.

Multidirectional instability is not clearly understood. Excessive capsular laxity has been proposed as the key component. However, because ligaments fail to resist humeral head translation until they are tensioned, glenohumeral instability in the mid range of motion cannot be explained by capsuloligamentous pathology alone. Capsulolabral augmentation is designed to increase glenohumeral stability by 2 separate mechanisms: deepening the glenoid concavity and reducing capsular laxity. This is accomplished by shifting the capsule to buttress the glenoid labrum. Hence, the glenolabral concavity in which the humeral head is stabilized by compression throughout the entire range is enhanced. The purposes of this study were to examine glenolabral depth and glenohumeral stability before and after labral augmentation and to measure the effect of diminished capsular laxity on motion in clinically important positions. We compared glenolabral depth, resistance to humeral head displacement, and glenohumeral range of motion before and after capsulolabral augmentation. Glenolabral depth was measured as the lateral displacement of the center of the humeral head translating from the glenoid fossa. We recorded a mean increase in glenoid depth of 1.9 mm inferiorly, 2.0 mm posteroinferiorly, and 0.9 mm posteriorly (P <.02). Resistance to humeral head displacement was measured by use of the stability ratio, defined as the translatory force required to displace the humeral head divided by the force compressing the humeral head into the glenoid fossa. The mean stability ratio was increased by 0.24 inferiorly and 0.24 posteroinferiorly (P <.02). Motion was measured by achieving 30 degrees and 60 degrees elevation in the 0 degrees, 30 degrees, 60 degrees, and 90 degrees planes of elevation and measuring the extent of possible internal rotation for each of these 8 positions when the capsule was tensioned to exert 1000 N-mm of torque. Reduction of internal rotation in these positions was a mean of 15 degrees at 1000 N-mm of torque. This study demonstrates that humeral head stability within the glenolabral fossa is increased by local capsular augmentation. A simultaneous reduction in capsular laxity is achieved, which partially limits glenohumeral motion. Understanding the biomechanical effect of this procedure helps the physician to establish surgical goals and to explain to patients the rationale of why this procedure may be clinically efficacious.

Posterior instability.

Posterior shoulder instability is a pathology that is increasingly seen in athletes. Excessive capsular laxity was originally proposed as the key component. Recent cadaveric and arthroscopic work has identified the importance of glenolabral integrity and glenoid depth in maintaining glenohumeral stability. Arthroscopic techniques to treat posterior instability are emerging. Until recently, reports of arthroscopic reconstruction focused entirely on capsular glenohumeral stability by altering two separate mechanisms: deepening of the glenoid concavity and reducing the capsular joint volume. This is accomplished by shifting the capsule to buttress the glenoid labrum. Thus increasing capsular tension increases the resultant compressive force vector into a deepened glenolabral concavity that, when combined together, enhances glenohumeral stability. In clinical and laboratory settings, we have shown that posteroinferior shoulder instability is associated with both capsular laxity and well-defined pathological lesions of the glenolabral concavity. Our results indicate that arthroscopic posterior capsulolabral repair and augmentation is a useful tool to restore the depth of the glenolabral concavity and to reduce the redundant posteroinferior capsule. This technique is effective in treating posteroinferior instability.

A prospective, multipractice study of shoulder function and health status in patients with documented rotator cuff tears.

A total of 191 patients from 29 orthopedic practices are analyzed in this report. All had full-thickness tears documented by imaging tests and/or surgical observation; 190 had tears of the supraspinatus, 54 had tears of the infraspinatus, and 13 had tears of the subscapularis. The greatest functional deficits were in the ability to place 8 pounds on a shelf at the level of the head (93% unable), the ability to throw overhand (93% unable), and the ability to sleep on the affected side (86% unable). The SF-36 physical role function and comfort scores were 27% and 48%, respectively, of those of age- and sex-matched controls. Of the variables suggested by a review of the literature, only female sex, involvement of the infraspinatus in the cuff tear, and workers' compensation claims were significantly correlated with lower shoulder function in this series of patients.

Capsulolabral augmentation for the the management of posteroinferior instability of the shoulder.

BACKGROUND: Posteroinferior instability of the shoulder has been associated with capsular laxity. The purposes of the present study were to describe the pathological morphology of the posteroinferior aspect of the glenolabral fossa in patients with primary posteroinferior instability and to prospectively examine the efficacy of managing this instability with use of an arthroscopic posteroinferior capsulolabral augmentation procedure. METHODS: Forty-one patients who had posteroinferior instability of the shoulder were managed with an arthroscopic shift of the posteroinferior aspect of the capsule to the adjacent labrum and were followed for a minimum of twelve months. Thirty-two patients had a primary procedure, and nine had a revision procedure. The mean duration of follow-up was twenty-eight months (range, twelve to sixty-nine months). All of the patients had presented with a symptomatic, positive finding on the jerk test and had participated in a minimum of six months of rehabilitation that had failed to relieve the symptoms. The patients were evaluated prospectively with a motion and stability examination and the Simple Shoulder Test. In addition, they completed the Short Form-36 Health Survey (SF-36) and a questionnaire on the outcome of treatment. RESULTS: Lesions affecting the posteroinferior aspect of the glenolabral concavity were seen in thirty-four patients (83 percent): five had labral detachment, seven had chondral or labral erosion, nine had capsular and synovial stripping, and thirteen had a labral split or tear. The mean score (and standard deviation) on the Simple Shoulder Test improved from 5.5 +/- 3.4 points to 8.1 +/- 3.3 points (p = 0.0023), and two of the eight SF-36 parameters improved significantly (p < 0.05). Conversely, nineteen patients who were receiving Workers' Compensation did not show any improvement in either of the two parameters. Thirty-five patients had improved stability of the shoulder, and the findings on all physical examinations had improved significantly (p < 0.0001). Twenty-eight patients had a perception of residual stiffness; this finding was in contrast to the mean score on the flexibility examination, which had not changed significantly at the time of the latest follow-up. CONCLUSIONS: Posteroinferior instability of the shoulder is associated not only with capsular laxity but also with well defined lesions of the glenolabral concavity. Arthroscopic capsulolabral augmentation to reduce posterior capsular laxity and to restore the depth of the glenolabral concavity has been shown to be effective treatment of this condition after a mean duration of follow-up of twenty-eight months.

Complications of open anterior stabilization of the shoulder.

Complications of surgery for glenohumeral instability are relatively uncommon. When they occur, salvaging failures and obtaining a stable joint can be awesome challenges. Accurate recognition of the cause of the instability and application of the appropriate surgical technique are critical. Deficiencies of the glenoid concavity, the anterior capsule, or the subscapularis may be present and require correction. Overtightening a shoulder and eliminating its normal laxity should be avoided. Loose or malpositioned hardware about the glenohumeral joint must be recognized as soon as possible and removed. The goal of treatment is to correct the deficient stabilizing mechanisms without altering normal glenohumeral function.

Arthroscopic posterior capsular repair.

Posterior shoulder instability is associated with capsular laxity and well-defined pathologic lesions of the gleno-labral concavity. Most arthroscopic techniques have concentrated on capsular shift or plication of capsular laxity. This article demonstrates that arthroscopic capsulolabral plication simultaneously can augment the glenolabral concavity to restore the glenoid depth, and can reduce excessive capsular laxity of the redundant posteroinferior capsule. This method has proven effective in treating posterior instability.

Posteroinferior glenoplasty can change glenoid shape and increase the mechanical stability of the shoulder.

The treatment of recurrent posterior glenohumeral instability remains an unsolved clinical problem. Although various types of capsulorraphy have been advocated, outcome studies indicate that it is difficult to achieve a balance between stability and mobility. Alterations of the bony glenoid for posterior instability have been proposed, but are not well understood from a mechanical perspective. This investigation had 2 purposes: (1) to determine in a cadaver model if posteroinferior glenoplasty can change the shape of the glenoid, and (2) to determine if altering the shape of the glenoid can increase the mechanical stability of the glenohumeral joint. We determined the effective glenoid shape in 7 normal cadaver glenoids by tracking the path of the center of the humeral head as it was translated across the glenoid face in 8 different directions. These determinations enabled us to calculate the maximum effective slope of the glenoid in each direction. We then determined the mechanical stability of the glenoids in each of the 8 directions by measuring the tangential force required to dislocate the shoulder under a 50-N compressive load. The ratio of the dislocating force to the compressive load was defined as the stability ratio. All measurements were repeated after a standardized posteroinferior glenoplasty was performed. Posteroinferior glenoplasty increased the posteroinferior glenoid depth from 3.8 +/- 0.6 mm to 7.0 +/- 1.8 mm and shifted the center of the humeral head an average of 2.2 mm anteriorly and 1.8 mm superiorly. These changes in dimension could be directly visualized as an immediate mechanical consequence of the glenoplasty procedure, particularly because of the insertion of the bone wedge. Glenoplasty increased the posteroinferior glenoid slope from 0.55 +/- 0.07 to 0.83 +/- 0.12 and increased the posteroinferior stability ratio from 0.47 +/- 0.10 to 0.81 +/- 0.17. This is a more than 70% increase in the tangential force that can be resisted before dislocation. The increase can be quantitatively understood as a direct mechanical consequence of the altered shape of the glenoid concavity. These numbers indicate that, in this cadaveric model, posteroinferior glenoplasty results in defined changes in the effective glenoid shape and in the mechanical stability of the glenohumeral joint. However, this study does not establish the role of this procedure in the clinical management of posterior glenohumeral instability.

Glenohumeral motion after complete capsular release.

The range of glenohumeral motion is primarily limited by the joint capsule. If the capsule is contracted, greater restriction in glenohumeral motion is exhibited. Release of a tight capsule has been an effective means of managing refractory stiffness of the glenohumeral joint. The effect of a complete capsular release on glenohumeral kinematics has not been previously studied in a cadaver model. Elevation, rotation, and translation of eight cadaveric glenohumeral preparations were studied before and after complete capsular release. As the intact joint was positioned near the limits of motion, glenohumeral torque rose rapidly with relatively small concomitant increases in elevation and rotational angles. Notable torque, due to tension in the capsule or cuff, ensued only after glenohumeral elevation reached approximately 80% of maximal range. After complete capsular release, maximal elevation increased on average 15%, yet retained definitive endpoints due to residual tension in the rotator cuff. Axial humeral rotation with an intact capsule decreased as maximum elevation approached, especially at elevation angles greater than 60 degrees. Maximum internal rotation was less than external, for all planes except +90 degrees. After complete capsular release, the greatest net gains for external rotation tended to be in the posterior scapular planes, whereas gains for internal rotation tended to be in the anterior scapular planes. Maximal translation in an intact vented capsule was 21 mm, 14 mm, and 15 mm in the anterior, posterior, and inferior directions, respectively. After complete capsular release, translation increased in all positions with maximal anterior, posterior, and inferior translations of 28 mm, 25 mm, and 28 mm, respectively. In general, relative gains in translation were greater in planes posterior to the scapula and at extremes of the range of motion. Although large glenohumeral translations were measured, no preparation could be dislocated before or after complete capsular release. Complete capsular release significantly increased glenohumeral range of motion and translation. The intact rotator cuff myotendinous units serves to limit the range of motion and translation after all capsuloligamentous attachments are rendered incompetent by complete capsular release.

Management of the stiff shoulder.

Shoulder stiffness occurs as a result of (1) contractures of the intraarticular capsule or muscle-tendon units or (2) adhesions within the extraarticular humeroscapular or scapulothoracic motion interface. These contractures or adhesions may occur independently or in combination. A thorough history and physical examination usually reveal the diagnosis (idiopathic frozen shoulder or posttraumatic stiff shoulder) and the anatomical locations of fibrosis that is causing stiffness, and identifies other treatable conditions associated with shoulder stiffness (such as diabetes). A gentle home program of passive stretching is effective in most patients. When the home program is not effective, a manipulation or surgical release may be indicated. If manipulation is not effective, capsular contractures are best released arthroscopically as this allows circumferential release without damaging the rotator cuff and thus allows rehabilitation without the need to protect the rotator cuff. The humeroscapular motion interface adhesions can be released either open or arthroscopically, but we believe that an open release combined with an arthroscopic capsular release is quicker and does not interfere with rehabilitation. When necessary, operative management coupled with an aggressive rehabilitation program can provide significant relief of pain and restoration of shoulder motion. Approximately 90% of patients can expect a good result with this treatment algorithm.

The lateral impaction of the shoulder.

17 patients had radiographic demonstration of injury to the clavicle, scapula and ribs from an impact delivered to the lateral shoulder. The study included 13 males and 4 females whose ages ranged from 18 to 83 years (average 45 years). Most injuries were sustained in falls or motor vehicle accidents. Analysis of these cases suggests a biomechanical hypothesis concerning the transmission of the impact forces within the shoulder girdle. According to this hypothesis, the impaction force applied to the lateral shoulder is transmitted from outside inward following two paths. The anterior and superior path passes through the acromio-clavicular joint, the clavicle, the costo-clavicular joint and the sterno-clavicular joint. The posterior and inferior path is transmitted within the gleno-humeral joint, the scapula and the scapulo-thoracic joint. Major impacting force is required to disrupt the anterior and posterior arches of the shoulder girdle. When both of these supporting structures are damaged, the patient is at risk for more serious injuries, including disruption of the thorax, shoulder joint, brachial plexus and neck.

Useful boundaries of the subacromial bursa.

The anatomic boundaries the subacromial bursa may serve as a useful guide for surgical orientation and safety. The goals of this study were to measure the minimum distance between the subdeltoid reflection of the subacromial bursa and the circumflex branch of the axillary nerve and to identify relationships between the margins of the subacromial bursa and the acromion, rotator cuff, and acromioclavicular joint. Seventeen fresh-frozen cadavers (mean age, 69 years), were included. Eleven cadavera were dissected only after the subacromial bursa was injected with a latex solution to define the peripheral boundaries of the bursa. The bursal margins were always 2 cm or more from the anterolateral corner of the bursal acromial surface and the bursa lined the anterior half of the anteroposterior distance of the acromion. The mean distances from all points of the acromion to the axillary nerve averaged approximately 5 cm. The mean minimum distance from the subdeltoid bursal reflection to the axillary nerve was 0.8 +/- 0.5 cm with a range of 0.0 to 1.4 cm. In the unelevated extremity, the inferior bursal reflection was always cephalad to the axillary nerve even when the two structures were apposed. Surgeons should exercise caution when approaching the inferior boundary of the subdeltoid bursal reflection because of the proximity to the axillary nerve. We recommend coupling previously reported "safe deltoid-split" distances to this useful anatomic landmark to prevent nerve injury. Furthermore, the central location of the anterolateral corner of the acromion within the bursal space can be applied to needle placement for injection, arthroscopic diagnosis or treatment and mini-open rotator cuff repairs.

The humeroscapular motion interface.

Motion between the humerus and scapula commonly is described as glenohumeral motion. However, humeroscapular motion occurs at two distinct sites. In addition to the motion at the diarthrodial glenohumeral joint, movement occurs between the proximal humerus and related structures and the surrounding sleeve of structures, including the acromion, deltoid, coracoid, coracoacromial ligament, and the muscles attached to the coracoid. This site of nonarticular shoulder motion is defined as the humeroscapular motion interface. Nonarticular humeroscapular motion can be documented and measured using standard magnetic resonance imaging techniques. The maximum average interfacial motion using axial images was 29.1 mm, which occurred at the level of the maximum diameter of the humeral head. Interfacial motion varied depending on the site measured. If pathologic conditions such as adhesions secondary to trauma or surgery interfere with or obliterate this space at sites of significant sliding motion, overall shoulder motion will be limited. Successful treatment of shoulder stiffness related to humeroscapular restraints is likely to require restoration of the normal sliding motion at the humeroscapular motion interface, in addition to resolving restraints affecting the glenohumeral joint motion.

Optimizing arthroscopic knots using braided or monofilament suture.

Surgeons need to know how the material properties of a suture affect the security of a surgical knot. The purpose of this study was to compare the security of some clinically important arthroscopic knots when tied using a braided multifilament suture and to draw comparisons with results of similar knots tied with monofilament suture. Permanent braided polyester suture was used to test 10 knot configurations. Eight of the knots included (1) two types of initial cinching knots followed by (2) one of four combinations of half-hitches. We also tested the taut-line hitch locked with half-hitches and the original Revo knot. Each knot was subjected to cyclic loading followed by an ultimate load to failure. Clinical failure was defined as the maximum force that resulted in 3 mm of loop displacement. Force versus displacement data were obtained, and the maximal loop holding capacities were compared statistically. The Duncan loop with switched-post half-hitches and the Revo knot (Linvatec, Largo, FL) showed the highest knot-holding capacities (mean, 87N and 92N, respectively) when compared with all other configurations (P < .0001) for braided suture. A similar knot-holding capacity was described for monofilament suture using the Duncan loop locked with switched-post, reversed-direction half-hitches (mean, 81 N). All knots without post switching slipped completely at significantly lower loads than knots with post switching (monofilament, P < .001; braided, P < .0001). When compared with results of knots tied with monofilament suture, the braided switched-post configurations had smaller cyclic displacements (braided, 0.7 mm; monofilament, 1.7 mm). Although the Revo knot showed good strength for braided suture, it was significantly weaker than other configurations when tied with monofilament suture. Therefore, it is important to test the knot strength for a given suture material before applying it clinically.

Local arthroscopic bone grafting of a juxta-articular glenoid bone cyst.

This report describes a rare, juxta-articular bone cyst of the posterior glenoid that developed after a fracture of the glenoid in a 38-year-old male. The patient had persistent pain, popping and stiffness of his right shoulder for 3 years, and failed to improve after a nonoperative rehabilitation program. At arthroscopy, the senior author transported an autogenous bone graft from the bare area of the humeral head to fill the glenoid cyst arthroscopically. At second-look arthroscopy approximately 1 year after the index procedure, the bone graft had consolidated within the original cystic defect and the surface was covered with fibrocartilage. The graft harvest site posteriorly on the humeral head had healed with a small amount of scar tissue at the articular margin. Comfortable motion and function were restored.

Superior detachment of a glenoid labrum variant resembling an incomplete discoid meniscus in a wheelchair ambulator.

Symptoms of instability and painful clunking in the shoulder were found associated with superior detachment of an incomplete discoid glenoid labrum and biceps origin in a 25-year-old woman. The patient was paraplegic below the T4 level secondary to resection of a spinal cord astrocytoma at age of 17. Symptoms began after 3 years of wheelchair use and repetitive transfer injuries. On arthroscopic examination, only the central surface of the articular glenoid cartilage was visible because of labral coverage. The entire labrum was meniscoid without distinguishable variation. The superior labrum was in continuity with the root of the biceps tendon; however, the superior biceps-labral complex was completely stripped away from the underlying glenoid. The anterior, posterior and inferior labrum was firmly attached peripherally about the glenoid. An arthroscopic staple was used to reattach the biceps root and superior labrum to bone. At 6 year follow-up, the functional result was satisfactory.

Arthroplasty for arthritis and rotator cuff deficiency.

Massive and irreparable loss of rotator cuff tendon integrity can be associated with the development of glenohumeral and acromiohumeral arthritis. Loss of glenohumeral instability provided by the rotator cuff may initiate and perpetuate this unique condition of the shoulder. Proximal humeral replacement arthroplasty is the preferred surgical treatment; special techniques of this procedure are presented. Patients are gratified by the durable restoration of comfort and, to a lesser extent, function.

Arthroscopic management of refractory shoulder stiffness.

Glenohumeral stiffness is a major cause of shoulder disability and pain. Conventional management strategies often fail to yield consistent or prompt return of comfort and function. Over the past 5 years, we have employed a prospective approach to the evaluation and management of glenohumeral stiffness using arthroscopic release of capsular contractures for the most refractory. This report concerns the first 30 patients who failed at least 6 months (28 month mean) of nonoperative management for unilateral refractory shoulder stiffness and who were managed by arthroscopic capsular release. Fourteen patients were diabetic. Follow-up averaged 33 months (range 12 to 56 months). Each patients' motion and strength was documented according to the American Shoulder and Elbow Surgeons standard examination. Functional outcome measures were patient-assessed using the Simple Shoulder test before and after surgery. Before surgery, active range-of-motion of the affected shoulder average 41% of the opposite asymptomatic side. The day after surgery, motion had improved dramatically to a mean of 78%. An additional 15% of motion was gained after discharge from the hospital. The final motion averaged 93% of the opposite side. All Simple Shoulder Test (SST) parameters and six of nine SF-36 health status scores were improved significantly. Only 6% of patients were able to sleep comfortably on their side and 35% could place 1 lb. on a shelf at shoulder height before surgery. After surgery, 73% were able to sleep comfortably on the affected side and 83% were able to place 1 lb. on a shelf at shoulder height. There were no differences among all outcome measures between diabetic or nondiabetic patients. Three patients developed recurrent refractory stiffness. The only complication was a single axillary neuropraxia which resolved spontaneously. No patient developed instability. Arthroscopic capsular release can be a safe and effective tool in the management of refractory shoulder stiffness.

Practical guidelines to safe surgery about the subscapularis.

Surgical mobilization of an adherent or retracted subscapularis tendon is often necessary whenever an attempt is made to restore function to the glenohumeral joint subsequent to failed anterior reconstructive surgery. Surgical guidelines drawn from this study emphasize how a surgeon might accomplish this task effectively and avoid denervating the subscapularis, a muscle that is essential to anterior glenohumeral stability and strength. In this study we examined subscapularis innervation in 11 fresh-frozen cadaveric shoulders. The position of the subscapular nerve insertion points were recorded relative to easily identified surgical landmarks such as the axillary nerve, the conjoined tendon, and the anterior glenoid rim. The palpable anterior border of the glenoid rim deep to the subscapularis along with the medical border of the conjoined tendon can serve as guides to the subscapularis nerve insertion points, because all the nerves are no closer than 1.5 cm medial to these landmarks for all positions of humeral rotation in the unelevated arm. The lower subscapular nerve was found immediately posterior or just lateral to the axillary nerve. During a standard deltopectoral approach potential injury to the subscapularis innervation can be minimized by locating and protecting the axillary nerve, because it serves as a guide to the insertion point of the lower subscapularis nerve, the nerve closet to the surgical field.