Aimee Struk

Outcomes of reverse total shoulder arthroplasty as primary versus revision procedure for proximal humerus fractures.

BACKGROUND Reverse total shoulder arthroplasty (RTSA) has been shown to be an effective treatment for proximal humerus fracture (PHF). This study evaluates outcomes of all patients with PHF treated with RTSA as a primary procedure for acute PHF, a delayed primary procedure for symptomatic PHF malunion or nonunion, a revision procedure for failed PHF hemiarthroplasty (HA), or a revision procedure for failed open reduction and internal fixation (ORIF). METHODS Patients who underwent RTSA for PHF were evaluated for active range of motion and Shoulder Pain and Disability Index (SPADI), Simple Shoulder Test-12, American Shoulder and Elbow Surgeons (ASES), University of California-Los Angeles (UCLA) shoulder rating scale, Constant, and 12-Item Short Form Health Survey scores. Scaption and external rotation (ER) strength were also assessed. RESULTS RTSA was performed in 49 patients with PHF; 13 patients underwent RTSA for acute PHF, 13 for malunion or nonunion, 12 for failed PHF HA, and 11 for failed PHF ORIF. ER range of motion, SPADI, ASES, UCLA, and Constant scores achieved significance. The acute fracture group significantly outperformed the failed HA group in SPADI, ASES, and UCLA scores. The malunion/nonunion group significantly outperformed the failed HA group in ASES and UCLA scores. The acute fracture and malunion/nonunion groups each had significantly greater ER than the failed HA group. CONCLUSION RTSA is an effective treatment option for PHF as both a primary and a revision procedure. Primary RTSA outperformed RTSA done as a revision procedure. RTSA for acute PHF is comparable to RTSA for malunions and nonunions. Our outcomes of revision RTSA for failed HA and ORIF are more promising than previously published.

Incidence of early radiolucent lines after glenoid component insertion for total shoulder arthroplasty: a radiographic study comparing pressurized and unpressurized cementing techniques

BACKGROUND Total shoulder arthroplasty (TSA) is commonly performed for arthritic conditions of the shoulder. The outcome after TSA is generally good, but there are several modes of failure, with one of the more common reasons being glenoid loosening. One possible cause for glenoid loosening is inadequate cementation technique. The purpose of this study was to evaluate the incidence of lucent lines on the first postoperative radiograph using 2 different cementation techniques. MATERIALS AND METHODS One hundred consecutive patients had a pegged glenoid placed with 1 of 2 different cementation techniques. In 26 consecutive patients, the pegged glenoid component was cemented with a traditional minimal manual pressurization technique, whereas 74 underwent a contemporary 3-step pressurization cementation technique before implant insertion. The first postoperative radiograph was evaluated using the system of Lazarus et al, looking at the frequency of lucent lines. The radiographs were deidentified and were randomized and evaluated by 2 independent observers on 3 separate occasions. RESULTS The Kruskal-Wallis test showed significant differences between grades of radiolucent lines for pressurized versus unpressurized cementation techniques. There were significantly (P < .05) fewer lucent lines identified in the group that underwent contemporary 3-step pressurization as opposed to the group that underwent minimal manual pressurization. Intraobserver reliability and interobserver reliability with Cronbach α coefficients were good. CONCLUSION The 3-step pressurized cementation technique resulted in a low incidence of radiolucent lines around the glenoid implant in patients undergoing TSA. LEVEL OF EVIDENCE Level II, Prospective Cohort, Treatment Study.

Scapulohumeral rhythm in shoulders with reverse shoulder arthroplasty

BACKGROUND Little is known about kinematic function of reverse total shoulder arthroplasty (RTSA). Scapulohumeral rhythm (SHR) is a common metric for assessing muscle function and shoulder joint motion. The purpose of this study was to compare SHR in shoulders with RTSA to normal shoulders. METHODS Twenty-eight subjects, more than 12 months after unilateral RTSA, were recruited for an Institutional Review Board-approved study. Subjects performed arm abduction in the coronal plane with and without a 1.4-kg hand-held weight. Three-dimensional model-image registration techniques were used to measure orientation and position for the humerus and scapula from fluoroscopic images. Analysis of variance and Tukey tests were used to assess groupwise and pairwise differences. RESULTS SHR in RTSA shoulders (1.3:1) was significantly lower than in normal shoulders (3:1). Below 30° abduction, RTSA and normal shoulders show a wide range of SHR (1.3:1 to 17:1). Above 30° abduction, SHR in RTSA shoulders was 1.3:1 for unweighted abduction and 1.3:1 for weighted abduction. Maximum RTSA shoulder abduction in weighted trials was lower than in unweighted trials. SHR variability in RTSA shoulders decreased with increasing arm elevation. CONCLUSION RTSA shoulders show kinematics that are significantly different from normal shoulders. SHR in RTSA shoulders was significantly lower than in normal shoulders, indicating that RTSA shoulders use more scapulothoracic motion and less glenohumeral motion to elevate the arm. With these observations, it may be possible to improve rehabilitation protocols, with particular attention to the periscapular muscles, and implant design or placement to optimize functional outcomes in shoulders with RTSA.

Electromyographic analysis of reverse total shoulder arthroplasties.

BACKGROUND Understanding how reverse total shoulder arthroplasty (RTSA) affects muscle activation may help refine it. This study evaluated deltoid and upper trapezius activity during shoulder abduction, flexion, and external rotation in RTSA recipients. METHODS Fifty individuals were recruited for this study: 33 were ≥6 months postunilateral RSTA, and 17 comprised our control group. Control individuals easily performed all functional tasks and had no history of shoulder pathology or pain. RTSA participants were divided into 3 groups according to implant design. Participants performed weighted and unweighted abduction in the coronal plane, forward flexion in the sagittal plane, and unweighted external rotation. Electromyography activation of the anterior, lateral, and posterior aspects of the deltoid and the upper trapezius muscles was recorded bilaterally. Motion capture using passive reflective markers quantified 3-dimensional motions of both shoulders. RESULTS During abduction and flexion, deltoid and upper trapezius activity was significantly increased in RTSA shoulders. Posterior deltoid activation was highest in shoulders with the medial glenosphere/lateral humerus implant. Medial glenosphere/medial humerus shoulders were most similar to the control groups anterior, lateral, and posterior deltoid muscle activation during weighted flexion. CONCLUSIONS RTSA increases muscle activation compared with normal shoulders. RTSA often restores stability and motion but not normal deltoid or upper trapezius activation. Increased muscle activation in shoulders with RTSA suggests less efficiency. RTSAs with lateral or medial glenosphere centers of rotation had mostly similar muscle activation. Average posterior deltoid activation did not exceed 20% of maximal voluntary isometric contraction for any group during unweighted external rotation, and differences between groups were <5% maximal voluntary isometric contraction.

Rate of Improvement following Volar Plate Open Reduction and Internal Fixation of Distal Radius Fractures.

Purpose. To determine recovery timeline of unstable distal radius fractures treated by open reduction and internal fixation with a locking volar plate. Methods. Data was collected prospectively on a consecutive series of twenty-seven patients during routine post-operative visits at 2 and 6 weeks, and 3, 6, 12 and 24 months. Range of motion measures and grip strength for both wrists were recorded. Results. Greatest gains were made within the first 3 months after surgery. Supination and pronation returned more quickly than flexion or extension, with supination and pronation both at 92% of the uninjured wrist at 3 months. Only flexion improved significantly between 3 and 6 months. All wrist motions showed some improvement until 1 year. Grip strength returned to 94% of the uninjured wrist by 12 months. Conclusions. Range of motion improvement will be greatest between 2 weeks and 3 months, with improvement continuing until 12 months. Grip strength should return to near normal by one year. Function and pain will improve, but not return to normal by the end of 12 months. Clinical Relevance. These results provide the surgeon with information that can be shared with patients on the anticipated timeline for normal recovery of function and strength.

Primary reverse total shoulder arthroplasty outcomes in patients with subscapularis repair versus tenotomy

BACKGROUND Reverse total shoulder arthroplasty (RTSA) is now performed at nearly the same rate as anatomic total shoulder arthroplasty in the United States. Repair of the subscapularis is of vital importance in total shoulder arthroplasty; however, its utilization in RTSA has recently been questioned. METHODS This is a retrospective comparative study from prospectively collected data comparing the outcomes and complications after primary RTSA with or without subscapularis repair. The study includes 202 patients who underwent primary RTSA at a single institution by a single surgeon using the same implant between 2007 and 2012. Average clinical follow-up was greater than 3 years in both groups. Outcome scores, clinical range-of-motion and strength measurements, and complications including dislocations are reported. RESULTS At an average follow-up of greater than 3 years, there were no significant differences in clinical range of motion, strength, and rates of complications including dislocations. External rotation was 24° in the subscapularis repair group and 26° in the no-repair group. There were no differences in the American Shoulder and Elbow Surgeons shoulder score. Subjective measures included the Shoulder Pain and Disability Index; University of California, Los Angeles shoulder rating scale; Simple Shoulder Test; and normalized Constant outcome scores. There were 0 dislocations (0%) in the subscapularis repair group and 3 dislocations in the no-repair group (2.6%), which were not significantly different. CONCLUSION Primary RTSAs with or without subscapularis repair have similar clinical outcome scores, range of motion, strength, and rates of complications including dislocations at 3 years of follow-up.

Arthroscopy and manipulation versus home therapy program in treatment of adhesive capsulitis of the shoulder: a prospective randomized study.

This study determined in a prospective manner if arthroscopic shoulder capsular release can decrease the duration of adhesive capsulitis symptoms when compared with a nonoperative home therapy program. Patients randomized to the operative group underwent arthroscopic capsular release and manipulation of the shoulder. Immediately after surgery they began the same stretching program as the nonoperative group, which consisted of terminal range of motion low-grade stretches twice daily for at least 15 minutes per session for 3 months. Twenty-six patients granted consent for the study (final analyses included 10 operative and 7 nonoperative). There were no statistical differences between the groups regarding gender, age (operative mean age, 51.5 ± 11.1 years; nonoperative mean age, 52.0 ± 6.8 years) or treatment outcome. This prospective, randomized study, which compared arthroscopic capsular release to a gentle home stretching program, demonstrated both treatment options to be effective treatment modalities.

Shoulder arthroplasty and its effect on strain in the subscapularis muscle

BACKGROUND Increasing the thickness of the prosthetic humeral head on subscapularis strain in patients undergoing total shoulder arthroplasty has not been elucidated. The optimal postoperative rehabilitation for total shoulder arthroplasty that does not place excessive strain on the subscapularis is not known. We hypothesize that the use of expanded non-anatomic humeral heads during shoulder replacement will cause increased tension in the repaired subscapularis. We identified a recommended passive range of motion program without invoking an increase in tension in the repaired subscapularis, and determined the impact of the thickness of the humeral head on subscapularis strain. METHODS Eight fresh-frozen, forequarter cadaver specimens were obtained. An extended deltopectoral incision was performed and passive range-of-motion exercises with the following motions were evaluated: external rotation, abduction, flexion, and scaption. An optical motion analysis system measured strain in the subscapularis. The same protocol was repeated after performing a subscapularis osteotomy and after placement of an anatomic hemiarthroplasty of three different thicknesses. FINDINGS For abduction and forward flexion, we observed a trend of decreasing strain of the subscapularis, as the laxity is removed with increasing humeral head component thickness. With the short humeral head, strain was similar to native joint with passive scaption and flexion but not with external rotation or abduction. INTERPRETATION The passive range of motion that minimizes tension on the subscapularis is forward flexion and scaption. Therefore, passive forward flexion or scaption does not need to be limited, but external rotation should have passive limits and abduction should be avoided.

Instrumented Trial Prosthesis for Intraoperative Measurements of Joint Reaction Forces during Reverse Total Shoulder Arthroplasty

Although soft tissue tension is an important factor in the clinical performance of reverse total shoulder arthroplasty (RTSA), this tension has not been quantified intraoperatively. Knowledge of the shoulder joint reaction forces during RTSA could facilitate the optimal placement of implant components to minimize the risk of both intraand postoperative complications. We developed a strain gauge instrumented trial glenosphere to measure shoulder joint reaction forces during RTSA. The strain gauges and their connections were hermetically sealed against body fluids by biocompatible materials. All materials in direct body contact were biocompatible. In this study, we introduce the structure and calibration results of the instrumented prosthesis. We also demonstrate the practical use of the prosthesis on a cadaveric shoulder. The instrumented prosthesis showed mean measurement errors of approximately 3.4% for forces up to 400 N. A maximum joint reaction force of 132 N was observed during abduction in a single cadaver specimen. This sensor will be useful for quantifying soft tissue tension during RTSA surgery.

The effect of lower socioeconomic status insurance on outcomes after primary shoulder arthroplasty

BACKGROUND Patient-reported outcomes (PROs) are becoming increasingly important to define successful outcomes. With the potential transition toward quality-based reimbursement, identifying risk factors for poor surgical outcomes becomes increasingly important. This study compared functional and PROs of primary shoulder arthroplasty in patients aged younger than 65 years with lower socioeconomic insurance compared with those with private insurance. METHODS A retrospective review of all primary shoulder arthroplasties in patients aged younger than 65 was performed at a single institution. Patients were stratified according to insurance type (private vs. Medicare/Medicaid) with 2-year minimum follow-up. Preoperative, postoperative, and improvements in range of motion, visual analog scale (VAS) pain, and PROs were compared. RESULTS We evaluated 143 shoulders (64 Medicare/Medicaid, 79 private insurance). Age, race, diagnosis, and type of arthroplasty were similar between groups. Patients with Medicare/Medicaid insurance demonstrated worse PROs before and after surgery, despite similar range of motion at both assessments. Despite poorer PROs postoperatively, both groups demonstrated similar improvements after surgery. Complications and reoperation were more common in the socioeconomically disadvantaged group (14% vs. 9%, P = .3; 11% vs. 6%, P = .2, respectively). DISCUSSION Medicaid and Medicare patients aged younger than 65 years undergoing shoulder arthroplasty demonstrate poorer preoperative and postoperative PRO measures compared with similar patients with private insurance. However, both groups demonstrate similar improvements in scores from baseline.