Daniel F. Massimini

Results of Arthroscopic Capsulolabral Repair: Bankart Lesion Versus Anterior Labroligamentous Periosteal Sleeve Avulsion Lesion

PURPOSE The purpose of this study was to evaluate the results of arthroscopic capsulolabral repair for traumatic anterior shoulder instability and to compare the outcome in patients who have Bankart lesions versus those with anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesions. METHODS This study included 99 patients (93 shoulders), 72 male and 17 female, with a mean age of 32 years, who underwent arthroscopic Bankart repair for traumatic, recurrent anterior shoulder instability, by use of suture anchors. In 67 shoulders (72%) a discrete Bankart lesion was repaired, and in 26 shoulders (28%) an ALPSA lesion was repaired. The 2 groups were analyzed with regard to the number of preoperative dislocations and number of postoperative recurrences. RESULTS At a mean follow-up of 47 months (range, 24 to 98 months), recurrence of instability was documented in 10 shoulders (10.7%). Of the shoulders, 5 had Bankart lesions (7.4%) and 5 had ALPSA lesions (19.2%) (P = .0501). The mean number of dislocations or subluxations before the index surgery was significantly higher in the ALPSA group (mean, 12.3 [range, 2 to 57]) than in the Bankart group (mean, 4.9 [range, 2 to 24]) (P < .05). However, there were no significant differences in the number of anchors used, incidence of minor glenoid erosion, or incidence of bony Bankart lesions between the groups (P > .05 for all). CONCLUSIONS Patients with ALPSA lesions present with a higher number of recurrent dislocations than those with discrete Bankart lesions. In addition, the failure rate after arthroscopic capsulolabral repair is higher in the ALPSA group than in the Bankart group. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Transfer of pectoralis major for the treatment of irreparable tears of subscapularis: DOES IT WORK?

Transfer of pectoralis major has evolved as the most favoured option for the management of the difficult problem of irreparable tears of subscapularis. We describe our experience with this technique in 30 patients divided into three groups. Group I comprised 11 patients with a failed procedure for instability of the shoulder, group II included eight with a failed shoulder replacement and group III, 11 with a massive tear of the rotator cuff. All underwent transfer of the sternal head of pectoralis major to restore the function of subscapularis. At the latest follow-up pain had improved in seven of the 11 patients in groups I and III, but in only one of eight in group II. The subjective shoulder score improved in seven patients in group I, in one in group II and in six in group III. The mean Constant score improved from 40.9 points (28 to 50) in group I, 32.9 (17 to 47) in group II and 28.7 (20 to 42) in group III pre-operatively to 60.8 (28 to 89), 41.9 (24 to 73) and 52.3 (24 to 78), respectively. Failure of the tendon transfer was highest in group II and was associated with pre-operative anterior subluxation of the humeral head. We conclude that in patients with irreparable rupture of subscapularis after shoulder replacement there is a high risk of failure of transfer of pectoralis major, particularly if there is pre-operative anterior subluxation of the humeral head.

Arthroscopic capsular release for refractory shoulder stiffness: A critical analysis of effectiveness in specific etiologies

HYPOTHESIS The purpose of this study is to report and compare the outcome of arthroscopic capsular release in patients with shoulder stiffness with post-traumatic, postsurgical, and idiopathic etiologies. We hypothesize that patients with idiopathic or post-traumatic stiffness have better outcomes after arthroscopic capsular release than those with shoulder stiffness with a postsurgical etiology. MATERIALS AND METHODS A retrospective review of 115 patients who underwent arthroscopic capsular release for refractory shoulder stiffness was performed. There were 60 men and 55 women with a mean age of 49 years (range, 27 to 81 years). The patients were divided into 3 groups according to the etiology of stiffness: post-traumatic (26 patients), postsurgical (48 patients), and idiopathic (41 patients). Arthroscopic capsular release was performed in all patients after a mean of 9 months of physical therapy (range, 6 to 13 months). RESULTS At a mean follow-up of 46 months (range, 25 to 89 months), the overall subjective shoulder value in all groups improved from 29% to 73% and the age- and gender-adjusted Constant score improved from 35% to 86%. The mean pain score decreased from 7.5 to 1, and mean active forward flexion, external rotation, and internal rotation increased from 97 degrees , 14 degrees , and the L5 vertebral level, respectively, to 135 degrees , 38 degrees , and the T11 vertebral level, respectively (P < .0001). There was no significant difference between the outcomes of idiopathic and post-traumatic stiffness (P = .7). However, the Constant score and subjective shoulder value were significantly lower in the postsurgical group compared with the idiopathic and post-traumatic groups (P = .0001 and P = .006, respectively). CONCLUSIONS Arthroscopic capsular release is an effective treatment for refractory shoulder stiffness. Patients with idiopathic and post-traumatic shoulder stiffness have better outcomes than patients with postsurgical stiffness.

Non-invasive determination of coupled motion of the scapula and humerus—An in-vitro validation

Measuring the motion of the scapula and humerus with sub-millimeter levels of accuracy in six-degrees-of-freedom (6-DOF) is a challenging problem. The current methods to measure shoulder joint motion via the skin do not produce clinically significant levels of accuracy. Thus, the purpose of this study was to validate a non-invasive markerless dual fluoroscopic imaging system (DFIS) model-based tracking technique for measuring dynamic in-vivo shoulder kinematics. Our DFIS tracks the positions of bones based on their projected silhouettes to contours on recorded pairs of fluoroscopic images. For this study, we compared markerlessly tracking the bones of the scapula and humerus to track them with implanted titanium spheres using a radiostereometric analysis (RSA) while manually manipulating a cadaver specimens arms. Additionally, we report the repeatability of the DFIS to track the scapula and humerus during dynamic shoulder motion. The difference between the markerless model-based tracking technique and the RSA was ±0.3 mm in translation and ±0.5° in rotation. Furthermore, the repeatability of the markerless DFIS model-based tracking technique for the scapula and humerus was ±0.2 mm and ±0.4°, respectively. The model-based tracking technique achieves an accuracy that is similar to an invasive RSA tracking technique and is highly suited for non-invasively studying the in-vivo motion of the shoulder. This technique could be used to investigate the scapular and humeral biomechanics in both healthy individuals and in patients with various pathologies under a variety of dynamic shoulder motions encountered during the activities of daily living.

In-vivo glenohumeral translation and ligament elongation during abduction and abduction with internal and external rotation.

Study DesignBasic Science. To investigate humeral head translations and glenohumeral ligament elongation with a dual fluoroscopic imaging system.BackgroundThe glenohumeral ligaments are partially responsible for restraining the humeral head during the extremes of shoulder motion. However, in-vivo glenohumeral ligaments elongation patterns have yet to be determined. Therefore, the objectives of this study were to 1) quantify the in-vivo humeral head translations and glenohumeral ligament elongations during functional shoulder positions, 2) compare the inferred glenohumeral ligament functions with previous literature and 3) create a baseline data of healthy adult shoulder glenohumeral ligament lengths as controls for future studies.MethodsFive healthy adult shoulders were studied with a validated dual fluoroscopic imaging system (DFIS) and MR imaging technique. Humeral head translations and the superior, middle and inferior glenohumeral ligaments (SGHL, MGHL, IGHL) elongations were determined.ResultsThe humeral head center on average translated in a range of 6.0mm in the anterior-posterior direction and 2.5mm in the superior-inferior direction. The MGHL showed greater elongation over a broader range of shoulder motion than the SGHL. The anterior-band (AB)-IGHL showed maximum elongation at 90° abduction with maximum external rotation. The posterior-band (PB)-IGHL showed maximum elongation at 90° abduction with maximum internal rotation.DiscussionThe results demonstrated that the humeral head translated statistically more in the anterior-posterior direction than the superior-inferior direction (p = 0.01), which supports the concept that glenohumeral kinematics are not ball-in-socket mechanics. The AB-IGHL elongation pattern makes it an important static structure to restrain anterior subluxation of the humeral head during the externally rotated cocking phase of throwing motion. These data suggest that in healthy adult shoulders the ligamentous structures of the glenohumeral joint are not fully elongated in many shoulder positions, but function as restraints at the extremes of glenohumeral motion. Clinically, these results may be helpful in restoring ligament anatomy during the treatment of anterior instability of the shoulder.

Open Versus Arthroscopic Acromioclavicular Joint Resection: A Retrospective Comparison Study

PURPOSE The purpose was to compare open and arthroscopic acromioclavicular joint (ACJ) resection. METHODS We retrospectively reviewed 103 patients (105 shoulders) who underwent ACJ resection between 2000 and 2005. There were 56 women and 47 men with a mean age of 48 years. The mean duration of follow-up was 51 months (range, 15 to 91 months). Arthroscopic ACJ resection by use of a direct approach was performed in 81 shoulders (group A), and open ACJ resection was performed in 24 shoulders (group B). Results were graded according to pain relief both subjectively and objectively with cross-body adduction testing and direct palpation of the ACJ, subjective shoulder value, Constant score, and improved function. RESULTS The Constant scores increased from 50 (range, 34 to 65) to 89 (range, 39 to 100) in group A (P < .0001) and from 46 (range, 22 to 63) to 87 (range, 43 to 100) in group B (P < .0001). There was no statistical difference in the postoperative normalized Constant score between group A and group B (P = .47). Pain with cross-body adduction testing and palpation of the ACJ improved in 76 shoulders (94%) in group A and 22 shoulders (92%) in group B. No patients had signs or symptoms of ACJ anteroposterior instability. Revision ACJ resection was performed in 5 patients (5 shoulders [6.2%]) in group A and 1 shoulder (4.2%) in group B (P = .37). The radiographs of the patients who underwent revision showed that 3 patients (3.7%) from group A had regrowth of the distal clavicle; in addition, 2 patients (2.5%) from group A and 1 patient (4.3%) from group B had incomplete distal clavicle excision. CONCLUSIONS This study did not show a significant difference in the outcome between arthroscopic and open ACJ resection. Incomplete excision and regrowth of the distal clavicle are the most common causes of revision. Although only the arthroscopic group showed a small percentage of patients (3.7%) with regrowth of the distal clavicle, the number is too small to assume that this complication is the result of the arthroscopic technique only. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Glenohumeral Contact Kinematics in Patients After Total Shoulder Arthroplasty

BACKGROUND Knowledge of in vivo glenohumeral joint contact mechanics after total shoulder arthroplasty may provide insight for the improvement of patient function, implant longevity, and surgical technique. The objective of this study was to determine the in vivo glenohumeral joint contact locations in patients after total shoulder arthroplasty. We hypothesized that the glenohumeral joint articular contact would be centered on the glenoid surface because of the ball-in-socket geometric features of the implants. METHODS Dual-plane fluoroscopic images and computer-aided design models were used to quantify patient-specific glenohumeral articular contact in thirteen shoulders following total shoulder arthroplasty. The reconstructed shoulder was imaged at arm positions of 0 degrees, 45 degrees, and 90 degrees of abduction (in the coronal plane) and neutral rotation and at 90 degrees of abduction with maximum internal and external rotation. The patients were individually investigated, and their glenohumeral joint contact centroids were reported with use of contact frequency. RESULTS In all positions, the glenohumeral joint contact centroids were not found at the center of the glenoid surface but at an average distance (and standard deviation) of 11.0 +/- 4.3 mm from the glenoid center. Forty (62%) of the sixty-five total contact occurrences were found on the superior-posterior quadrant of the glenoid surface. The position of 0 degrees of abduction in neutral rotation exhibited the greatest variation of quadrant contact location; however, no contact was found on the superior-anterior quadrant of the glenoid surface in this position. CONCLUSIONS In vivo, glenohumeral joint contact after total shoulder arthroplasty is not centered on the glenoid surface, suggesting that kinematics after shoulder arthroplasty may not be governed by ball-in-socket mechanics as traditionally thought. Although contact locations as a function of arm position vary among patients, the superior-posterior quadrant seems to experience the most articular contact in the shoulder positions tested.

The accuracy and repeatability of an automatic 2D-3D fluoroscopic image-model registration technique for determining shoulder joint kinematics

Fluoroscopic imaging, using single plane or dual plane images, has grown in popularity to measure dynamic in vivo human shoulder joint kinematics. However, no study has quantified the difference in spatial positional accuracy between single and dual plane image-model registration applied to the shoulder joint. In this paper, an automatic 2D-3D image-model registration technique was validated for accuracy and repeatability with single and dual plane fluoroscopic images. Accuracy was assessed in a cadaver model, kinematics found using the automatic registration technique were compared to those found using radiostereometric analysis. The in vivo repeatability of the automatic registration technique was assessed during the dynamic abduction motion of four human subjects. The in vitro data indicated that the error in spatial positional accuracy of the humerus and the scapula was less than 0.30mm in translation and less than 0.58° in rotation using dual plane images. Single plane accuracy was satisfactory for in-plane motion variables, but out-of-plane motion variables on average were approximately 8 times less accurate. The in vivo test indicated that the repeatability of the automatic 2D-3D image-model registration was 0.50mm in translation and 1.04° in rotation using dual images. For a single plane technique, the repeatability was 3.31mm in translation and 2.46° in rotation for measuring shoulder joint kinematics. The data demonstrate that accurate and repeatable shoulder joint kinematics can be obtained using dual plane fluoroscopic images with an automatic 2D-3D image-model registration technique; and that out-of-plane motion variables are less accurate than in-plane motion variables using a single plane technique.

In vivo articular cartilage contact at the glenohumeral joint: preliminary report

BackgroundLittle is known about normal in vivo mechanics of the glenohumeral joint. Such an understanding would have significant implications for treating disease conditions that disrupt shoulder function. The objective of this study was to determine articular contact locations between the glenoid and humeral articular surfaces in normal subjects during shoulder abduction with neutral, internal, and external rotations. We hypothesized that glenohumeral articular contact is not perfectly centered and is variable in normal subjects tested under physiological loading conditions.MethodsOrthogonal fluoroscopic images and magnetic resonance image-based computer models were used to characterize the centroids of articular cartilage contact of the glenohumeral joint at various static, actively stabilized abduction and rotation positions in five healthy shoulders. The shoulder was investigated at 0°, 45°, and 90° abduction with neutral rotation and then at 90° abduction combined with active maximal external rotation and active maximal internal rotation.ResultsFor all the investigated positions, the centroid of contact on the glenoid surface for each individual, on average, was more than 5 mm away from the geometric center of the glenoid articular surface. Intersubject variation of the centroid of articular contact on the glenoid surface was observed with each investigated position, and 90° abduction with maximal internal rotation showed the least variability. On the humeral head surface, the centroids of contact were located at the superomedial quarter for all investigated positions, except in two subjects’ positions at 0° abduction, neutral rotation.ConclusionsThe data showed that the in vivo glenohumeral contact locations were variable among subjects, but in all individuals they were not at the center of the glenoid and humeral head surfaces. This confirms that “ball-in-socket” kinematics do not govern normal shoulder function. These insights into glenohumeral articular contact may be relevant to an appreciation of the consequences of pathology such as rotator cuff disease and instability.

Suprascapular nerve anatomy during shoulder motion: a cadaveric proof of concept study with implications for neurogenic shoulder pain

BACKGROUND The suprascapular nerve (SSN) carries sensory fibers which may contribute to shoulder pain. Prior anatomic study demonstrated that alteration in SSN course with simulated rotator cuff tendon (RCT) tears cause tethering and potential traction injury to the nerve at the suprascapular notch. Because the SSN has been implicated as a major source of pain with RCT tearing, it is critical to understand nerve anatomy during shoulder motion. We hypothesized that we could evaluate the SSN course with a novel technique to evaluate effects of simulated RCT tears, repair, and/or release of the nerve. METHODS The course of the SSN was tracked with a dual fluoroscopic imaging system in a cadaveric model with simulated rotator cuff muscle forces during dynamic shoulder motion. RESULTS After a simulated full-thickness supraspinatus/infraspinatus tendon tear, the SSN translated medially 3.5 mm at the spinoglenoid notch compared to the anatomic SSN course. Anatomic footprint repair of these tendons restored the SSN course to normal. Open release of the transverse scapular ligament caused the SSN to move 2.5 mm superior-posterior out of the suprascapular notch. CONCLUSION This pilot study demonstrated that the dynamic SSN course can be evaluated and may be altered by a RCT tear. Preliminary results suggest release of the transverse scapular ligament allowed the SSN to move upward out of the notch. This provides a biomechanical proof of concept that SSN traction neuropathy may occur with RCT tears and that release of the transverse scapular ligament may alleviate this by altering the course of the nerve.