Publications

The purpose of this study was to determine how implant characteristics affect in vivo shoulder kinematics after reverse shoulder arthroplasty (RSA). Kinematics of the affected upper limb were measured in 32 participants during five motions (scapular plane abduction, hand-to-head, hand-to-back, internal/external rotation at 90° abduction, and circumduction) using optical motion capture. Shoulder abduction, plane of elevation, and internal/external rotation range of motion (ROM), peak angles, and continuous kinematics waveforms were calculated for each motion. Multiple regression was used to identify associations between kinematics and implant characteristics of lateralization, humeral retroversion, glenosphere size, glenosphere tilt, glenoid eccentricity, and implant neck-shaft angle (135° or 145°). Less humeral retroversion was associated with greater shoulder rotation ROM (p = 0.036) and greater plane of elevation ROM (p = 0.024) during circumduction, while less eccentricity was associated with more posterior plane of elevation during hand-to-back (p = 0.021). The 145° implant was associated with greater internal/external shoulder rotation ROM (p < 0.001), greater internal shoulder rotation (p = 0.002), and greater plane of elevation ROM (p = 001) during the hand-to-back. The 145° implant was also associated with more internal/external rotation ROM (p = 0.043) during shoulder rotation and more abduction ROM during circumduction (p = 0.043). During the hand-to-back motion, individuals having 135° neck-shaft angle implants were more abducted from 21 to 51% of the motion and were less internally rotated from 70 to 100% of the motion, while more lateralization was associated with less internal rotation from 90 to 100% of the motion. Retroversion and implant neck-shaft angle are the primary implant characteristics associated with in vivo shoulder kinematics during complex motions after RSA.

PURPOSE: To determine whether posterior glenoid bone block augmentation performed for the treatment of recurrent posterior shoulder instability succeeds in restoring stability and is associated with rates of complications or clinical failures comparable to other glenoid bone augmentation procedures.

METHODS: A comprehensive search of PubMed, MEDLINE, and EMBASE databases was performed. Level of evidence studies I to IV pertaining to posterior bone block augmentation reporting on outcomes or complications were included. The search was carried out in accordance with the Preferred Reported Items for Systematic Reviews and Meta-analyses guidelines.

RESULTS: Screening of titles, abstracts, and manuscripts with application of inclusion and exclusion criteria yielded 17 full-text articles reporting on 269 shoulders undergoing bone block augmentation. Surgical technique varied between studies with regard to graft type (iliac crest, 13 studies; scapular spine, 2; acromion, 1; distal tibia allograft, 1), graft positioning (medial to 1.5 cm lateral to glenoid surface, equatorial to subequatorial), and open versus arthroscopic technique (open, 10 studies; arthroscopic, 4; both, 3). Four of the 8 studies with pre- and postoperative patient-reported outcomes (PROs) showed significant improvements in these outcomes at final follow-up. The postoperative outcomes ranged from 60 to 90 for Rowe scores (n = 7 studies) and 79 to 90 for Walch-Duplay scores (n = 7 studies). Complications were commonly encountered, with high rates of recurrent instability (0% to 73%) and revision procedures (0% to 67%) across different studies.

CONCLUSION: Posterior bone block augmentation for recurrent posterior shoulder instability does not reliably yield substantial improvements in PROs, and complications are frequently observed. The substantial heterogeneity across studies and the small number of patients precludes any substantive judgements as to the superiority of one surgical technique over another.

LEVEL OF EVIDENCE: IV, systematic review of level III and IV studies.

PURPOSE: To determine the in vivo effects of superior capsule reconstruction (SCR) on glenohumeral kinematics during abduction and to compare those kinematics results with patient-reported outcomes, range of motion, and strength.

METHODS: Dynamic biplane radiography was used to image 10 patients with irreparable rotator cuff tears while performing scapular plane abduction pre- and 1-year post-surgery. Shoulder kinematics were determined by matching subject-specific computed tomography-based bone models to the radiographs using a validated tracking technique.

RESULTS: No change was detected in static acromiohumeral distance (-0.7 ± 2.1 mm; P = .35); however, average dynamic acromiohumeral distance decreased (2.7 ± 1.2 mm to 2.3 ± 1.0 mm; P = .035) from pre- to 1-year post-surgery, respectively. The humeral head position was 0.5 ± 0.5 mm more superior 1-year post-surgery compared with pre-surgery (P = .01). Glenohumeral abduction increased from pre-surgery (150 ± 20°) to 1-year post-surgery (165 ± 10°) (P = .04) and all patient-reported outcomes improved from pre-surgery to 1-year post-surgery (all P < .002). A more posterior shift in humeral head position was associated with improved American Shoulder and Elbow Surgeons Shoulder Score from pre-surgery to 1-year post-surgery (r = 0.71, P = .02).

CONCLUSIONS: These data suggest that SCR may not depress the humeral head during functional abduction, as previously postulated, and postoperative improvements in subjective and clinical outcomes may be affected by mechanisms other than changes in shoulder kinematics.

CLINICAL RELEVANCE: In vivo kinematics changes after SCR are small and do not correspond to previously postulated changes.

BACKGROUND: The "distance to dislocation" (DTD) calculation has been proposed as 1 method to predict the risk of recurrent dislocation after arthroscopic Bankart repair for an "on-track" shoulder. Rates of recurrent dislocation at specific DTD values are unknown.

HYPOTHESIS: Among patients with "on-track" shoulder lesions who underwent primary arthroscopic Bankart repair, the rate of recurrent dislocation would increase as DTD values decrease.

STUDY DESIGN: Case-control study; Level of evidence, 3.

METHODS: We performed a retrospective analysis of 188 patients with "on-track" shoulder lesions who underwent primary arthroscopic anterior labral repair between 2007 and 2019, with a minimum 2-year follow-up. Glenoid bone loss, Hill-Sachs interval, glenoid track, and DTD were determined from preoperative magnetic resonance imaging scans. The rate of recurrent dislocation was determined at 2-mm DTD intervals. Univariate and multivariate regression analyses were used to evaluate the relationship between recurrent dislocation, patient characteristics, and bone loss variables. A multivariate regression model was created to predict the probability of failure at continuous DTD values. A subgroup analysis of failure rate based on collision sports participation was also performed.

RESULTS: A total of 29 patients (15.4%) sustained recurrent dislocations. Patient age (P = .046), multiple dislocations (P = .03), glenoid bone loss (P < .001), Hill-Sachs interval length (P < .001), and DTD (P < .001) were all independent predictors of failure. As the DTD decreased, the rate of recurrent dislocation increased. Below a DTD threshold of 10 mm, the recurrent dislocation rate increased exponentially. Up to a threshold of 24 mm, the failure rate for collision athletes remained >12.3%, independent of the DTD. Conversely, the failure rate among noncollision athletes decreased steadily as the DTD increased.

CONCLUSION: For "on-track" shoulder lesions, as the DTD approached 0 mm ("off-track" threshold), the risk of recurrent dislocation after arthroscopic Bankart repair increased significantly. Below a DTD threshold of 10 mm, the risk of failure increased exponentially. The risk of recurrent dislocation for collision sports athletes remained elevated at higher DTD values than for noncollision athletes.

BACKGROUND: The role of tear etiology in outcomes after rotator cuff repair is not well understood.

PURPOSE/HYPOTHESIS: The purpose of this study was to determine the difference in outcomes after rotator cuff repair based on tear etiology. We hypothesized that traumatic rotator cuff tears will have greater improvements in functional outcome measures and range of motion (ROM) than atraumatic tears.

STUDY DESIGN: Cohort study; Level of evidence, 3.

METHODS: We conducted a chart review of 221 consecutive patients who underwent arthroscopic rotator cuff repair; prospectively collected preoperative and minimum 2-year postoperative data were evaluated. Shoulder ROM, strength, and standard shoulder physical examination findings were recorded pre- and postoperatively. Outcome measures included visual analog scale for pain, Subjective Shoulder Value (SSV), 10-item Patient-Reported Outcomes Measurement Information System (PROMIS-10; physical and mental components), and American Shoulder and Elbow Surgeons (ASES) form.

RESULTS: Of the 221 patients, 73 had traumatic tears and 148 had atraumatic/degenerative tears. There were no differences in age, body mass index, or Charlson Comorbidity Index between groups. Patients in the atraumatic cohort had significantly longer duration of symptoms before presentation (18 vs 7 months; P < .01). Preoperatively, the traumatic cohort had less motion to forward flexion (mean ± SD; 138° ± 43.7° vs 152° ± 29.8°; P = .02). Postoperatively, both groups experienced significant improvements in visual analog scale and SSV scores (P < .001 each). However, only the traumatic cohort demonstrated improvements in ASES and PROMIS-10 physical component scores. Patients with traumatic rotator cuff tears had lower preoperative SSV and less motion than those with atraumatic tears, but they had greater improvements in SSV (40.6% ± 39.0% vs 29.2% ± 39.7%; P = .005) and forward flexion (21.6° ± 48.6° vs 2.3° ± 48.2°; P < .001), as well as strength in forward flexion, external rotation, and internal rotation (P < .001, P = .003, and P = .002, respectively).

CONCLUSION: Patients with traumatic rotator cuff tears have worse preoperative symptoms and more functional deficits but experience greater improvements in ROM, strength, and perceived shoulder function than those with degenerative/atraumatic tears.

PURPOSE: To assess demographic factors, comorbidities, radiographic variables, and injury patterns as potential prognostic indicators of poor functional and patient-reported outcomes following arthroscopic rotator cuff repair in patients with concomitant glenohumeral osteoarthritis.

METHODS: A retrospective review of consecutive patients with glenohumeral osteoarthritis who underwent arthroscopic supraspinatus repairs between 2013 and 2018 with a minimum of 1-year follow up was performed. Demographic variables included age, tobacco use, alcohol use, diabetes, sex, hypercholesterolemia, and body mass index while injury patterns included partial- versus full-thickness tear, bicep tendon involvement, and osteoarthritis severity. Multivariate linear regression was used to identify independent predictors of visual analog pain scale (VAS), subjective shoulder value (SSV), and American Shoulder and Elbow Surgeons (ASES) score as well as active range of motion (ROM) in forward flexion (FF) and external rotation (ER). Binary logistic regression was used to identify predictors of repair failure as well as postoperative strength in FF and ER.

RESULTS: In total, 91 patients (mean age 61.48 ± 9.4 years) were identified with an average follow up of 26.3 ± 5.7 months. Repair failures occurred in 9.9% (9/91 patients) of the total cohort. Postoperative outcomes were significantly improved with regards to visual analog pain scale, subjective shoulder value, ASES score, ROM in FF, FF strength, and external rotation strength compared with preoperative baseline. Obesity (P = .023) and diabetes (P = .010) were significant independent predictors of greater pain scores postoperatively. Obesity (P = .029) and tobacco use (P = .007) were significant predictors of lower ASES scores postoperatively. Finally, moderate-to-severe osteoarthritis was a significant risk factor for poor ROM and strength in FF postoperatively compared to mild osteoarthritis (P = .029). No variables were predictive of repair failure.

CONCLUSIONS: Tobacco use, obesity, and diabetes are associated with worse pain and patient-reported outcomes following arthroscopic rotator cuff repair in the context of glenohumeral OA. In addition, moderate-to-severe OA is associated with worse strength and forward flexion compared to those with mild OA.

LEVEL OF EVIDENCE: Level III, retrospective cohort study.

BACKGROUND: The time from symptom onset to surgery has been shown to impact functional outcomes after repair of traumatic rotator cuff tears (RCTs), but this temporal relationship has not yet been evaluated in patients with atraumatic, degenerative cuff tears. Furthermore, it has been shown that over time, atraumatic cuff tears tend to enlarge and become more symptomatic, retracted, and atrophic-factors that have been shown to decrease success rates after repair. The aim of this study was to evaluate the relationship between the time from symptom onset to surgery and postoperative outcomes in patients with atraumatic RCTs.

METHODS: We performed a retrospective cohort study of patients with degenerative, atraumatic RCTs who underwent surgery performed by 2 fellowship-trained shoulder surgeons and had at least 12 months of postoperative follow-up. These patients were divided into 2 cohorts based on the duration between symptom onset and surgery: early (<12 months) and delayed (≥12 months). The primary outcome measures included reoperation rate and failure of repair. Secondary outcomes included clinical measures of strength and range of motion and patient-reported outcome measures consisting of the Subjective Shoulder Value, visual analog scale for pain, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment, and Brophy-Marx Activity Scale at last follow-up.

RESULTS: Of the 143 patients who met the inclusion criteria, 78 (54.5%) underwent surgery within 1 year of symptom onset whereas 65 (45.5%) underwent surgery after at least 1 year. There were no differences between groups regarding demographic or tear characteristics. At final follow-up, there were no differences between the early- and late-surgery groups regarding retear rate (12% vs. 9%, P = .65), reoperation rate (5% vs. 3%, P = .54), postoperative range of motion in any plane (P > .05), strength in external rotation and internal rotation, visual analog scale pain score, or Subjective Shoulder Value. A greater proportion of the early group (61%) than the late group (46%) experienced improvement in supraspinatus strength of ≥1 grade on manual muscle testing (P = .02) and post hoc analysis.

CONCLUSION: Despite our knowledge of the natural history of chronic, atraumatic RCTs, delaying surgical treatment for 1 year or more does not appear to significantly impact postoperative outcomes. Thus, it is reasonable for physicians to recommend either conservative or surgical treatment depending on patient-specific factors and expectations.

BACKGROUND: Glenohumeral osteoarthritis (OA) is a common comorbidity in patients with rotator cuff tears. However, the efficacy of rotator cuff repair in patients with concomitant glenohumeral OA is still heavily debated. Thus, the purpose of this study was to compare the clinical and functional outcome measures following arthroscopic rotator cuff repairs in patients with concomitant glenohumeral OA vs. those without glenohumeral OA.

METHODS: A retrospective review of 206 consecutive patients who underwent arthroscopic supraspinatus repairs (both isolated and with accompanying infraspinatus and/or subscapularis involvement) between 2013 and 2018 with a minimum of 1-year follow-up was performed. Patients were separated into 2 groups based on the presence or absence of concomitant glenohumeral OA. The primary outcome was failure of repair, defined as the need for revision repair or a retear confirmed on postoperative magnetic resonance imaging. The secondary outcomes were patient-reported outcome measures including the visual analog scale pain score, Subjective Shoulder Value, and American Shoulder and Elbow Surgeons score; active range of motion (ROM); and strength testing. Within the OA cohort, a subgroup analysis was conducted to compare outcomes between patients with mild OA and patients with moderate to severe OA.

RESULTS: There were 91 patients in the glenohumeral OA group and 115 patients in the control group. Significant differences in postoperative forward flexion (FF) ROM (153.55° ± 21.07° vs. 160.14° ± 17.26°, P = .001) and external rotation (ER) ROM (46.91° ± 11.95° vs. 52.25° ± 11.60°, P = .001) were observed between the glenohumeral OA and control groups. There were no significant differences between groups in revision repairs, retears, postoperative internal rotation ROM, all preoperative ROMs, all patient-reported outcome measures, and all strength parameters (all P > .05). For the subgroup analysis, there were 70 patients in the mild OA group and 21 patients in the moderate to severe OA group. We found a significant difference in postoperative FF strength (88.4% vs. 61.9% with 5 of 5 strength, P = .010) and ER strength (89.9% vs. 71.4% with 5 of 5 strength, P = .046) between the mild OA group and moderate to severe OA group. There were no significant differences between the groups in all other outcome measures.

DISCUSSION: Rotator cuff repair remains an excellent treatment option in patients with concomitant glenohumeral OA. The data in this study demonstrate that rotator cuff repairs in patients with concomitant glenohumeral OA have similar clinical and functional outcomes to repairs in patients without OA with the exception of slightly decreased postoperative FF and ER ROM. Patients with moderate to severe OA may have slightly decreased FF and ER strength outcomes compared with patients with mild OA.

In recent years, an appreciation for the dynamic relationship between glenoid and humeral-sided bone loss and its importance to the pathomechanics of glenohumeral instability has substantially affected modern treatment algorithms. However, comparatively less attention has been paid to the influence of glenoid version on glenohumeral instability. Limited biomechanical data suggest that alterations in glenoid version may affect the forces necessary to destabilize the glenohumeral joint. However, this phenomenon has not been consistently corroborated by the results of clinical studies. Although increased glenoid retroversion may represent an independent risk factor for posterior glenohumeral instability, this relationship has not been reliably observed in the setting of anterior glenohumeral instability. Similarly, the effect of glenoid version on the failure rates of surgical stabilization procedures remains poorly understood.

PURPOSE: To identify the rate and risk factors of posterior labral involvement in operatively managed Bankart lesions and assess the effectiveness of MRI arthrogram for preoperative identification of such injury patterns.

METHODS: A consecutive cohort of patients undergoing arthroscopic Bankart repair were retrospectively reviewed. All subjects underwent a prearthroscopy MRI arthrogram. Operative findings were used as the gold standard for posterior labral tear extension. Patient demographic and surgical data were then analyzed to identify independent factors associated with the presence of concomitant posterior labral injury.

RESULTS: Of 124 patients undergoing arthroscopic Bankart stabilization, 23 (19%) were noted to demonstrate posterior labral injury on arthroscopic evaluation. Factors associated with injury to the posterior labrum included those sustaining two or fewer dislocations events (P =.001), an earlier average presentation (P = .001), and a reported "contact" mechanism of dislocation (P = .02). Posterior labral involvement did not correlate with surgical positioning (beach-chair versus lateral) or the need for revision surgery. On the basis of review of preoperative imaging, MRI arthrogram demonstrated a sensitivity of 83% and a specificity of 95% for detection of posterior labral injury.

CONCLUSIONS: Posterior propagation of Bankart lesions is relatively common following shoulder dislocations, with a rate of 18.5%. Risk factors for posterior labral extension include two or fewer dislocations, early presentation from the time of injury, and contact sports. On the basis of these findings, careful assessment of the posterior labrum on MRI arthrogram may reveal the majority, but not all, of these lesions.

LEVEL OF EVIDENCE: Level III, retrospective case-controlled study.