Load carriage changes tibiofemoral arthrokinematics during ambulatory tasks in recruit-aged women.

The introduction of women into U.S. military ground close combat roles requires research into sex-specific effects of military training and operational activities. Knee osteoarthritis is prevalent among military service members; its progression has been linked to occupational tasks such as load carriage. Analyzing tibiofemoral arthrokinematics during load carriage is important to understand potentially injurious motion and osteoarthritis progression. The study purpose was to identify effects of load carriage on knee arthrokinematics during walking and running in recruit-aged women. Twelve healthy recruit-aged women walked and ran while unloaded (bodyweight [BW]) and carrying additional + 25%BW and + 45%BW. Using dynamic biplane radiography and subject-specific bone models, tibiofemoral arthrokinematics, subchondral joint space and center of closest contact location between subchondral bone surfaces were analyzed over 0-30% stance (separate one-way repeated measures analysis of variance, load by locomotion). While walking, medial compartment contact location was 5% (~ 1.6 mm) more medial for BW than + 45%BW at foot strike (p = 0.03). While running, medial compartment contact location was 4% (~ 1.3 mm) more lateral during BW than + 25%BW at 30% stance (p = 0.04). Internal rotation was greater at + 45%BW compared to + 25%BW (p < 0.01) at 30% stance. Carried load affects tibiofemoral arthrokinematics in recruit-aged women. Prolonged load carriage could increase the risk of degenerative joint injury in physically active women.

Overhead athletes have comparable intraoperative injury patterns and clinical outcomes to non-overhead athletes following surgical stabilization for first-time anterior shoulder instability at average 6-year follow-up.

BACKGROUND AND HYPOTHESIS: Anterior shoulder instability is a common problem affecting young, athletic populations that results in potential career-altering functional limitations. However, little is known regarding the differences in clinical outcomes after operative management of overhead vs. non-overhead athletes presenting with first-time anterior shoulder instability. We hypothesized that overhead athletes would have milder clinical presentations, similar surgical characteristics, and diminished postoperative outcomes when compared with non-overhead athletes after surgical stabilization following first-time anterior shoulder instability episodes. METHODS: Patients with first-time anterior shoulder instability events (subluxations and dislocations) undergoing operative management between 2013 and 2020 were included. The exclusion criteria included multiple dislocations and multidirectional shoulder instability. Baseline demographic characteristics, imaging data, examination findings, and intraoperative findings were retrospectively collected. Patients were contacted to collect postoperative patient-reported outcomes including American Shoulder and Elbow Surgeons score, Western Ontario Shoulder Instability Index score, Brophy activity index score, and Subjective Shoulder Value, in addition to return-to-work and -sport, recurrent dislocation, and revision rates. RESULTS: A total of 256 patients met the inclusion criteria, of whom 178 (70%) were non-overhead athletes. The mean age of the entire population was 23.1 years. There was no significant difference in concomitant shoulder pathology, preoperative range of motion, or preoperative strength between cohorts. A greater proportion of overhead athletes presented with instability events not requiring manual reduction (defined as subluxations; 64.1% vs. 50.6%; P < .001) and underwent arthroscopic surgery (97% vs. 76%, P < .001) compared with non-overhead athletes. A smaller proportion of overhead athletes underwent open soft-tissue stabilization compared with non-overhead athletes (1% vs. 19%, P < .001). Outcome data were available for 60 patients with an average follow-up period of 6.7 years. No significant differences were found between groups with respect to recurrent postoperative instability event rate (13.0% for overhead athletes vs. 16.8% for non-overhead athletes), revision rate (13.0% for overhead athletes vs. 11.1% for non-overhead athletes), American Shoulder and Elbow Surgeons score, Western Ontario Shoulder Instability Index score, Brophy score, Subjective Shoulder Value, or rates of return to work or sport. CONCLUSION: Overhead athletes who underwent surgery after an initial instability event were more likely to present with subluxations compared with non-overhead athletes. With limited follow-up subject to biases, this study found no differences in recurrence or revision rates, postoperative patient-reported outcomes, or return-to-work or -sport rates between overhead and non-overhead athletes undergoing shoulder stabilization surgery following first-time instability events. Although larger prospective studies are necessary to draw firmer conclusions, the findings of this study suggest that overhead athletes can be considered in the same treatment pathway for first-time dislocation as non-overhead athletes.

Dual Mini-Fragment Plate Fixation of Midshaft Clavicle Fractures Reduces Risk of Reoperation Compared With Single-Plate Fixation Techniques.

BACKGROUND: Recent studies have highlighted dual plating as a method of reducing high rates of postoperative complication after operative management of displaced midshaft clavicular fractures. However, few studies have reliably characterized reoperation rates and magnitude of risk reduction achieved when using dual versus anterior and superior single-plate techniques. HYPOTHESIS: There would be lower rates of reoperation among patients who underwent open reduction and internal fixation (ORIF) of displaced midshaft clavicular fractures via dual plating. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This was a retrospective analysis of patients who underwent ORIF for a displaced midshaft clavicular fracture between 2010 and 2021 at a level 1 trauma center with a minimum 12-month follow-up. Patients were separated into 3 cohorts based on fixation type: (1) orthogonal dual mini-fragment plate fixation, (2) superior plate fixation, and (3) anterior plate fixation. Data on patient characteristics, fracture pattern, and reoperations were documented. All-cause reoperation rates and hazard ratio (HR) estimates of dual, superior, and anterior plating were calculated using a multivariate multilevel mixed-effects parametric survival model. Significant confounders including high-risk fracture morphology and smoking status were controlled for in the final model. RESULTS: A final cohort of 256 patients was identified with mean follow-up of 4.9 ± 3.8 years. In total, 101 patients underwent superior plating, 92 underwent anterior plating, and 63 underwent dual plating. Overall, 31 reoperations took place (18 in superior, 12 in anterior, 1 in dual plating) among 22 patients. Major contributors to reoperation included symptomatic hardware (n = 11), nonunion (n = 8), deep infection (n = 7), and wound dehiscence (n = 2). Superior plating revealed the highest reoperation rate of 0.031 per person-years, followed by anterior plating with 0.026 per person-years and dual plating with 0.005 per person-years. Overall, single plating (either anterior or superior placement) had a nearly 8-fold greater risk of reoperation than dual plating (HR, 7.62; 95% CI, 1.02-56.82; P = .048). Further broken down by technique, superior plating had an 8-fold greater risk of reoperation than dual plating (HR, 8.36; 95% CI, 1.10-63.86; P = .041), but anterior plating did not demonstrate a statistically significant difference compared with dual plating (HR, 6.79; 95% CI, 0.87-52.90; P = .068). CONCLUSION: Dual-plate fixation represents an excellent treatment for displaced midshaft clavicular fractures, with low rates of nonunion and reoperation. When compared with single locked superior or anterior plate fixation, dual mini-fragment plate fixation has a nearly 8-fold lower risk of reoperation.

Criteria-based return-to-sport testing helps identify functional deficits in young athletes following posterior labral repair but may not reduce recurrence or increase return to play.

Background: The purpose of this study was to compare recurrent instability and return to play (RTP) in young athletes who underwent clearance to full activity based on a validated return-to-sport (RTS) test to those who underwent time-based clearance following primary posterior labral repair. Methods: This was a retrospective review of athletes with posterior shoulder instability who underwent primary arthroscopic posterior labral repair from 2012 to 2021 with minimum 1-year follow-up. Patients who underwent RTS testing at a minimum of 5 months postoperatively were compared to a historic control cohort of patients who underwent time-based clearance. Results: There were 30 patients in the RTS cohort and 67 patients in the control cohort (mean follow-up 32.1 and 38.6 months, respectively). Of the 30 patients who underwent RTS testing, 11 passed without failing any sections, 10 passed while failing 1 section, and 9 failed the RTS test by failing 2+ sections. No differences were found between the RTS and control cohort in the incidence of recurrent instability (6.7% vs. 9.0%), overall RTP (94.7% vs. 94.3%), RTP at the same level as before injury (84.2% vs. 80.0%), recurrent pain/weakness (23.3% vs. 25.4%), or revision surgery (0% vs. 3.0%), respectively. Discussion: While RTS testing in young athletes after posterior labral repair did not reduce recurrence or improve return to play compared to time-based clearance, two-thirds of athletes who underwent testing failed at least 1 section, indicating some functional deficit. Thus, RTS testing may help guide postoperative rehabilitation following posterior stabilization.

Increased Failure Rates After Arthroscopic Bankart Repair After Second Dislocation Compared to Primary Dislocation With Comparable Clinical Outcomes.

PURPOSE: The purpose of this study was to compare rates of recurrent dislocation and postsurgical outcomes in patients undergoing arthroscopic Bankart repair for anterior shoulder instability immediately after a first-time traumatic anterior dislocation versus patients who sustained a second dislocation event after initial nonoperative management. METHODS: A retrospective chart review was performed of patients undergoing primary arthroscopic stabilization for anterior shoulder instability without concomitant procedures and minimum 2-year clinical follow-up. Primary outcome was documentation of a recurrent shoulder dislocation. Secondary clinical outcomes included range of motion, Visual Analog Scale (VAS), American Shoulder and Elbow Surgeons Shoulder Score (ASES), and Shoulder Activity Scale (SAS). RESULTS: Seventy-seven patients (mean age 21.3 years ± 7.3 years) met inclusion criteria. Sixty-three shoulders underwent surgical stabilization after a single shoulder dislocation, and 14 underwent surgery after 2 dislocations. Average follow-up was 35.9 months. The rate of recurrent dislocation was significantly higher in the 2-dislocation group compared to single dislocations (42.8% vs 14.2%, P = .03). No significant difference was present in range of motion, VAS, ASES, and SAS scores. The minimal clinically important difference (MCID) was 1.4 for VAS and 1.8 for SAS scores. The MCID was met or exceeded in the primary dislocation group in 31/38 (81.6%) patients for VAS, 23/31 (74.1%) for ASES, and 24/31 for SES (77.4%) scores. For the second dislocation cohort, MCID was met or exceeded in 7/9 (77.8%) for VAS, 4/7 (57.1%) for ASES, and 5/7 for SES (71.4%) scores. CONCLUSION: Immediate arthroscopic surgical stabilization after a first-time anterior shoulder dislocation significantly decreases the risk of recurrent dislocation in comparison to those who undergo surgery after 2 dislocation events, with comparable clinical outcome scores. These findings suggest that patients who return to activities after a primary anterior shoulder dislocation and sustain just 1 additional dislocation event are at increased risk of a failing arthroscopic repair. STUDY DESIGN: Retrospective comparative study; Level of evidence, 3.

Reverse shoulder arthroplasty with preservation of the rotator cuff for primary glenohumeral osteoarthritis has similar outcomes to anatomic total shoulder arthroplasty and reverse shoulder arthroplasty for cuff arthropathy.

INTRODUCTION: Indications for reverse total shoulder arthroplasty (RSA) have expanded to include individuals with intact rotator cuffs such as patients with severe glenoid deformity or with concern of future rotator cuff insufficiency. The purpose of this study was to compare outcomes of RSA with an intact rotator cuff to RSA for cuff arthropathy and anatomic total shoulder arthroplasty (TSA). We hypothesized that outcomes of RSA with an intact rotator cuff would be comparable to RSA for cuff arthropathy and TSA but with diminished range of motion (ROM) compared with TSA. MATERIALS AND METHODS: Patients at one institution who underwent RSA and TSA between 2015 and 2020 with minimum 12-month follow-up were identified. RSA with preservation of the rotator cuff (+rcRSA) was compared to RSA for cuff arthropathy (-rcRSA) and anatomic TSA (TSA). Demographics and glenoid version/inclination were obtained. Pre- and postoperative ROM; patient-reported outcomes including visual analog scale (VAS), Subjective Shoulder Value (SSV), and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores; and complications were obtained. RESULTS: Twenty-four patients underwent +rcRSA, 69 underwent -rcRSA, and 93 underwent TSA. There were more women in the +rcRSA cohort (75.8%) than in the -rcRSA (37.7%, P = .001) and TSA (37.6%, P = .001) cohorts. Mean age of the +rcRSA cohort (71.1) was greater than that of TSA (66.0, P = .021) but similar to that of -rcRSA (72.4, P = .237). Glenoid retroversion was greater in +rcRSA (18.2°) compared with -rcRSA (10.5°, P = .011) but was similar to TSA (14.7°; P = .244). Postoperatively, there were no differences in VAS or ASES between +rcRSA vs. -rcRSA and +rcRSA vs. TSA. SSV was lower in +rcRSA (83.9) compared with -rcRSA (91.8, P = .021), but was similar to TSA (90.5, P = .073). Similar ROM was achieved in forward flexion, external rotation, and internal rotation at final follow-up between +rcRSA and -rcRSA, but TSA had greater external rotation (44° vs. 38°, P = .041) and internal rotation (6.5° vs. 5.0°, P = .001) compared with +rcRSA. There were no differences in complication rates. DISCUSSION: At short-term follow-up, preservation of the rotator cuff in RSA demonstrated similarly excellent outcomes and low complication rates compared with RSA with a deficient rotator cuff and TSA, except for slightly lower internal and external rotation compared with TSA. Although multiple factors deserve consideration when choosing between RSA and TSA, RSA with preservation of the posterosuperior cuff is a viable treatment option for glenohumeral osteoarthritis, particularly in patients with severe glenoid deformity or those at risk for future rotator cuff insufficiency.

Distance to Dislocation and Recurrent Shoulder Dislocation After Arthroscopic Bankart Repair: Rethinking the Glenoid Track Concept.

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.

Risk factors for complications and reoperation following operative management of displaced midshaft clavicle fractures.

BACKGROUND: Optimal management of a displaced midshaft clavicle fracture remains controversial. This study assessed demographic factors, fracture pattern, and surgical technique as potential predictors of surgical complications. Smoking, diabetes, obesity, polytrauma, high-energy mechanism, inpatient status, transverse or comminuted fractures, and single-plating technique were hypothesized to be associated with an increased risk of complications following clavicle fracture open reduction internal fixation (ORIF). METHODS: Consecutive patients with minimum 12-week follow-up from the trauma and sports medicine divisions at a single tertiary institution who presented with a midshaft clavicle fracture and underwent ORIF between 2007 and 2020 were retrospectively identified. Patient demographics, fracture pattern, plating technique, and postoperative complications were recorded. Postoperative complications were classified into major (reoperation) and minor (no reoperation) complications. Chi-squared statistics, Fisher's exact test, analysis of variance, Kruskal-Wallis test, and multivariate logistic regression modeling were utilized with a significance level set to P < .05. RESULTS: One hundred ninety-eight patients (average = 39.5 ± 14.6 years) were identified with an average follow-up of 9.1 ± 10.7 months. The cohort consisted of 155 males (78.3%), 62 smokers (31.3%), and 12 diabetics (6.1%). Injury characteristics revealed 80 transverse fractures (40.4%), 87 oblique fractures (43.9%), and 31 Z-type fractures (15.7%). Seventy-nine patients (39.9%) underwent superior plating, 72 (36.4%) underwent anterior plating, and 47 (23.7%) underwent dual plating. Overall, postoperative complications occurred in 47 patients (23.7%), 29 minor (14.6%) and 18 major (9.1%). Major complications requiring reoperation were symptomatic hardware, nonunion, deep infection, wound dehiscence, and broken hardware. Minor complications consisted of sensory deficit or paresthesia beyond peri-incisional numbness, superficial infections, postoperative pain and/or stiffness, and delayed union. Smoking status (P = .008), obesity (P = .009), and transverse or Z-type fractures (P = .002) were significant prognostic factors for overall complication risk. Only manual labor was predictive of minor complications (P = .019). Transverse or Z-type fractures and single plating were predictive of major complications (P = .004 and P = .008, respectively). No reoperations occurred in patients who underwent dual plating. Smokers (P = .027) with transverse/Z-type fractures (P = .022) were at the highest risk of reoperation with single plating. CONCLUSION: The overall rate of complications following ORIF of displaced midshaft clavicle fracture was 27.3%, with 9.1% requiring reoperation. Given relatively high complication rates, in instances when nonoperative vs. operative management is equivocal, nonoperative management should be strongly considered in obese patients, smokers, and patients who present with transverse or Z-type fracture. If operative management is indicated, use of dual plating may decrease reoperation rates.

Implant characteristics affect in vivo shoulder kinematics during multiplanar functional motions after reverse shoulder arthroplasty.

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.