Arthroscopic Bankart repair remains a popular treatment option for anterior shoulder instability, but the high reported recurrence rates have led to significant interest in identifying risk factors for failure and refining techniques and implants to improve outcomes. Recently, there has been significant interest in remplissage as an adjunct to Bankart repair, with less focus on repair technique, anchor placement, and anchor type. The use of retensionable anchors and the addition of a posteroinferior anchor have been previously described, but not evaluated in combination, and are simple changes a surgeon can make to their technique and anchor selection to improve biomechanical stability of their repair construct.

Background: All-suture anchors (ASAs) significantly reduced gap formation and increased strength compared with traditional fixation in a transosseous cadaveric quadriceps tendon repair model. However, the biomechanical performance of ASAs for unicortical quadriceps tendon repair has not been evaluated. Hypothesis: ASAs would reduce gap formation and exhibit comparable stiffness, yield load, and ultimate load to knotless hard-body suture anchors (SAs) for unicortical quadriceps tendon repair. Study Design: Controlled laboratory study. Methods: Eight matched pairs of male cadaveric knees were used to compare ASA and SA control repairs. Distal quadriceps tendons were prepared with 2 Krackow sutures using 1.3-mm suture tape. Sutures were fixed unicortically with 2 anchors using 2.6-mm ASAs or 4.75-mm SAs. Knees were actuated from 5° to 90° of flexion via the quadriceps tendon for 10 native preconditioning cycles and 250 cycles after repair at 0.1 Hz, with a peak force of 150 N per cycle. Repairs were loaded to failure at 50 mm/min. Gap formation (mm) during cyclic loading and stiffness (N/mm), yield load (N), and ultimate load (N) during load to failure were statistically compared between groups using paired t tests. Results: The ASA repair had significantly less gap formation at cycle 250 compared with the control repair (Δ = 4.2 mm [95% CI, 2.9 to 5.3 mm]; P < .001) and survived greater cycles before reaching a critical gap threshold of 5 mm (200 vs 50 cycles). No significant differences in stiffness or ultimate load were found between repairs. The yield load was significantly greater in the control group than the ASA group (Δ = 55 N [95% CI = 27-82 N]; P = .002). Conclusion: Unicortical quadriceps tendon repair with ASAs reduced gap formation by 43% compared with hard-body SAs. No significant differences in stiffness or ultimate load were observed, although a significantly greater yield load was found for the SA controls. Clinical Relevance: ASAs are a biomechanically viable alternative to hard-body SAs for unicortical quadriceps tendon repair, potentially resulting in less gap formation.

Background Subscapularis management with lesser tuberosity osteotomy repair in stemless total shoulder arthroplasty is particularly different in terms of suture fixation as opposed to stemmed humeral implants. Surgical techniques to achieve optimal soft tissue balance in lesser tuberosity osteotomy repairs differ based on the surgeon. The purpose of this study is to determine whether there is a difference in 2 years functional or clinical outcomes in stemless total shoulder arthroplasty patients treated with lesser tuberosity osteotomy repairs conducted with bone tunnels versus suture anchors. Methods A retrospective review was performed of a prospectively maintained, multi-center database of primary TSAs performed by multiple surgeons between 2019 and 2023 with minimum 2-year follow-up. A total of 81 patients met the study criteria, including 33 in the suture anchor cohort versus 48 in the bone tunnel cohort. Patient-reported outcomes (PRO) as well as range of motion (ROM) measurements were compared between the two groups for baseline results as well as at two year follow up. Results There was no statistically significant difference in age, sex, BMI, tobacco usage, or diabetes prevalence in either cohort (p=0.610, p=0.687, p=0.980), p=0.153, p=0.355, respectively). There was no statistically significant difference in PRO, ROM, or belly press test at baseline between patients treated with suture anchors and those treated with bone tunnels. At two years, there were no statistical differences in outcomes (PROs, ROM, or strength), other than worse FF in the suture anchor group (145 degrees vs 156 degrees, p=0.026). Conclusions The current study suggests equivalent two year functional and clinical outcomes for patients treated with suture anchors versus the conventional bone tunnels in LTO repair for stemless TSA patients. The two groups had similar baseline demographics, ROM, and PRO scores and performed similarly at two years follow up. Level of Evidence Level III; Retrospective Cohort Comparison Study

Background Despite increased recognition of risk factors, improved implant design, and advances in implant positioning, acromion fractures remain a common complication after reverse shoulder arthroplasty, which results in inferior outcomes. There is a paucity of literature focusing on strategies to prevent acromion fracture in patients undergoing reverse shoulder arthroplasty. The goals of the present study were to 1) create a model of weakened acromion bone by uniformly decreasing the bone volume in the acromion encompassing an area that corresponds to a Levy type 2 acromial fracture and 2) biomechanically evaluate a novel method of prophylactic fixation using threaded intramedullary pins. Methods Nine matched pairs of female fresh-frozen cadaveric scapulae were tested. After testing the native, intact acromion, a weakened acromion condition was created in the area that corresponded to a Levy type 2 acromial fracture using evenly spaced 1.8 mm drill holes, 2.5 mm apart, parallel to the glenoid line in the acromion. Testing was performed by simulating deltoid load. For the control side of the matched pair, the intact and weakened acromion stiffness was measured under cyclic loading followed by load to failure of the weakened acromion. For the prophylactic fixation study group, after cyclic testing of the intact and weakened acromion condition, two reinforcing 2.4 mm diameter threaded titanium compression pins were inserted. Cyclic loading of the pinned-weakened acromion was performed, followed by load to failure of the pinned-weakened acromion. Results Uniformly drilling cortical drill holes resulted in approximately 50% decreased bone volume, significantly decreased stiffness (P < .05 for control and prophylactic fixation groups), and significantly greater deformation at peak load (P < .05 both groups), indicating a valid model for acromion weakening. Prophylactic fixation with pinning of the weakened acromion resulted in superior biomechanical characteristics, including improved yield displacement (P = .004), yield load (P = .004), energy at yield (P < .001), ultimate displacement (P = .003), and ultimate load (P = .005). Conclusion Uniformly drilling holes in the area of a Levy type 2 acromion fracture can create sufficient bone volume loss that results in a biomechanically reproducible weakened acromion model. Prophylactic fixation of a weakened acromion with two 2.4 mm threaded titanium pins resulted in superior biomechanical characteristics, which helped to reduce complete, displaced fracture in the region of interest compared to the weakened acromion without pins. Future clinical studies are necessary to provide validation of the utility of this technique in vivo.

Background Humeral head pathomorphology is highly prevalent in glenohumeral osteoarthritis and can increase the challenge of restoration of native anatomy during anatomic total shoulder arthroplasty (aTSA). The goal of the present study was to evaluate the influence of preoperative computed tomography (CT)-based 3D humeral planning and standard transfer instrumentation on the restoration of normal humeral anatomy during aTSA with pathologic humeral specimens in a controlled laboratory setting. Methods Three experienced shoulder surgeons participated in a prospective, controlled laboratory study utilizing 3D-printed pathologic osteoarthritic humeri from CTs of existing patients, which were chosen to be -3, -1, 0, 1 and 3 size standard deviations of all patients in a large database. A realistic surgical setting was simulated. aTSA using the Arthrex Eclipse prosthesis were performed in three phases of the study. In phase 1, humeral cuts and implantations were performed without preoperative planning. In phase 2, preoperative planning was performed, and the cuts repeated on new prints of the same specimens. In phase 3, the same steps were repeated, with the additional use of standard transfer instrumentation. After digitization, deviations in the prosthetic and ideal center of rotation (COR), neck shaft angle (NSA), retrotorsion and cut thickness were assessed. Results There were no significant differences in NSA, deviation in planned resection height, or deviation in retortorsion from native between the three phases (p > 0.05). The M-L COR shift was significantly greater for Phase 1 compared to Phase 2 (2.8mm vs 1.6mm, p = 0.043). There were no other significant differences between phases for the M-L, A-P or 3D COR shifts. There were significantly fewer varus head cuts (13%) in Phase 3 compared to Phase 1 (47%) and Phase 2 (47%) (p = 0.043). Conclusions Preoperative CT-based humeral planning provides some modest improvements in medial to lateral humeral COR restoration and with the addition of standard transfer instrumentation, reduction in varus neck cuts in pathologic, osteoarthritic humeri in a controlled laboratory setting. The most important finding of the study is the avoidance of varus neck cuts with planning and transfer technology. While significant, the differences were overall modest compared to findings of previous studies for non-pathologic humeri, indicating the challenges associated with restoration of native anatomy in pathomorphologic humeri during aTSA and the need for continued development to refine planning and transfer tools.

Background:Prognostic indicators of lack of strength progression or poor self-reported function may alter rehabilitation decision-making following anterior cruciate ligament reconstruction (ACLR). The torque-velocity relationship is a noninvasive measure of muscle function that is altered following ACLR, but its prognostic value has not been explored. Purpose:To compare the torque-velocity relationship of knee extensors (quadriceps) and flexors (hamstrings) between the ACLR and uninvolved limbs and to determine whether the torque-velocity relationship was prognostic of subsequent achievement of satisfactory strength. Study Design:Cohort study; Level of evidence, 3. Methods:Participants following ACLR with bone-patellar tendon-bone or hamstring autografts completed isokinetic knee extension and flexion at 90°/s and 180°/s bilaterally, the International Knee Documentation Committee (IKDC) form, and Knee injury and Osteoarthritis Outcome Score (KOOS) at approximately 5.5 and 8.3 months post-ACLR. The torque-velocity relationship was defined as the difference in torque production across velocities, and relationships were analyzed using 2 × 2 analyses of variance. Binomial logistic regressions were used to determine the association between the torque-velocity relationship, age, sex, and time postsurgery with satisfactory knee extension strength, IKDC, and KOOS at visit 2. Results:This study included 189 participants (22.4 ± 9.3 years; 55.0% female). There were significant increases in the quadriceps torque-velocity relationship from visit 1 (0.22 Nm/kg) to visit 2 (0.34 Nm/kg, P < .001) but no differences in the uninvolved limb (P = .46) or for the hamstrings (P = .20). When controlling for sex, age, and graft type, higher visit 1 quadriceps torque-velocity relationships were predictive of a higher likelihood of achieving satisfactory knee extension strength (≥1.23 Nm/kg; odds ratio [OR], 1.05; P = .04). The model was associated with an acceptable IKDC score (≥75.9, P = .01), but the only significant individual predictor was age (OR, 0.94; P < .01). The model was not associated with KOOS Sport score at visit 2 (P = .24). Conclusion:Quadriceps torque-velocity relationships of the ACLR limbs increased across time but remained less than uninvolved limbs. Hamstrings torque-velocity relationships remained similar between limbs and across time. These findings indicate that the torque-velocity relationship of the quadriceps changed over time and was predictive of future satisfactory strength. Clinical Relevance:Clinicians may use a greater quadriceps torque-velocity relationship as a positive indication of a patient's ability to achieve satisfactory strength later in rehabilitation.

Objectives: Failure of a corticosteroid injection and therapy to provide relief for shoulder adhesive capsulitis results in increasing healthcare costs and patient morbidity from repeat injections and possible surgical intervention. The purpose of this study was to examine the effects of an extended-release corticosteroid injection in shoulder adhesive capsulitis. Methods: This was a phase 2, prospective, non-blinded single-arm study of patients with idiopathic adhesive capsulitis of the shoulder who received a single, image-guided extended-release corticosteroid injection. The visual analog pain scale (VAS) was measured up to 12 months after injection. Secondary endpoints included American Shoulder and Elbow (ASES) score, range of motion (ROM), and need for re-injection. Results: Thirty-nine patients with a mean age of 55 ± 9 years were included; 32 (82%) experienced adequate symptom resolution after a single injection. Mean VAS improved from 5 to 1.4 ( p < 0.01), and mean ASES score improved from 43 to 80 ( p < 0.01) by 6-week post-injection, with sustained improvement through 1-year follow-up. Patients demonstrated improvements in mean passive forward elevation (117–173°; p < 0.01), abduction (98– 162°; p < 0.01), and external rotation with the arm adducted (32–59°; p < 0.01). Conclusion: A single intra-articular injection of extended-release corticosteroid was associated with sustained improvements in pain relief, patient-reported outcomes, and ROM in patients with idiopathic shoulder adhesive capsulitis.

Background:Reverse total shoulder arthroplasty (RTSA) is an effective treatment option for multiple shoulder conditions. It is unclear if seasonal timing of surgery affects outcomes. Methods:Patients who underwent RTSA between 2015-2021 and were enrolled in a multicenter registry were eligible for inclusion. Date of surgery was divided into winter, spring, summer and fall. Patient reported outcomes, range of motion and complications at 2 years' follow up were assessed and compared between RTSA groups for each season. Results:863 patients were included. Breakdown by season was: winter (N = 214); spring (N = 183); summer (N = 178); fall (N = 288). There were no differences in 2-year clinical outcomes, range of motion, complications or strength between groups with the exception that patients who underwent RTSA in the fall had a higher Constant-Murley score and better active internal rotation at 90 degrees than in other seasons (p = 0.036 and p = 0.013, respectively). Conclusion:There were very few differences in clinical outcomes based on seasonal timing for patients who undergo RTSA. Patients should feel confident that their outcomes will not vary based on the season in which they undergo RTSA.

OBJECTIVES:Few studies have determined how individuals who undergo a second ACL reconstruction (ACLR) perform in terms of objective and patient-reported outcomes in the early rehabilitation period compared to individuals who undergo primary ACLR. This study investigated the difference in strength and functional outcomes 3-5 months postoperatively in revision ACLR patients compared to primary ACLR patients. DESIGN:Cross-Sectional Retrospective Chart Review. SETTING:Single university-based orthopaedic practice. PARTICIPANTS:143 patients who underwent ACLR (121 primary, 22 revision) MAIN OUTCOME MEASURES: Isokinetic knee extension and flexion strength at 60°/s and 180°/s, the IKDC, KOOS, and ACL-RSI 4.2 ± 0.7 months after ACLR. RESULTS:After controlling for age, sex, graft source, and time since surgery, there were no significant group differences for ACL-RSI (p = 0.771), IKDC (p = 0.950), and KOOS subscale scores (p = 0.335-0.740). Similarly, there were no significant group differences in isokinetic knee extension peak torque at 60°/s and 180°/s (p = 0.155, p = 0.147) and knee flexion peak torque 60°/s and 180°/s (p = 0.279, p = 0.325). Group LSIs were comparable for isokinetic knee extension and knee flexion. CONCLUSION:Three to five months postoperatively, revision ACLR patients performed similarly in terms of thigh strength, limb symmetry, and patient-reported function compared to primary ACLR patients.

Background:Reruptures and functional deficits can occur with conventional transosseous quadriceps tendon repair. Previous work has demonstrated the biomechanical superiority of adjustable transosseous metal cortical button fixation over conventional repair. Knotless all-suture anchor (ASA) buttons may provide a similar improvement but have not yet been investigated. Purpose:To biomechanically compare adjustable transosseous cortical fixation with knotless ASAs to traditional transosseous repair. Study Design:Controlled laboratory study. Methods:Eight matched pairs of male cadaveric knees were dissected to isolate and release the quadriceps tendon insertion. Paired knees were randomized to 2.6-mm knotless ASA or control repair, both with Krackow suturing using 1.7-mm suture tape. The ASA technique had two 1.6-mm tunnels through which the knotless ASA loops interlocked with the Krackow sutures. The control technique had three 2.4-mm tunnels through which suture tape tails were passed and tied over bone bridges. Knees were mounted onto a materials testing system and actuated from 5° to 90° of flexion via the quadriceps tendon for 10 native preconditioning cycles and 250 cycles after repair 0.1 Hz, with a peak force of 150 N per cycle. Repairs were loaded to failure at a rate of 50 mm/min. Outcomes included plastic gap formation (mm) during cyclic loading and stiffness (N/mm), yield load (N), and ultimate load (N) during load to failure. Paired t tests were used for statistical analysis (P < .05). Results:The ASA had significantly less gap formation at cycle 250 (mean Δ = 6.3 mm; P < .001) and superior stiffness (Δ = 17.7 N/mm; P = .004), yield load (Δ = 40 N; P = .014), and ultimate load (Δ = 127 N; P = .015) compared with the control. The mean transosseous control displacement surpassed the defined critical threshold for gap formation (5.0 mm) in this study by cycle 50, whereas the mean ASA displacement never did. Conclusion:Compared with conventional transosseous quadriceps tendon repair, adjustable ASA transosseous repair had 64% less tendon-bone gap formation, 35% greater stiffness, 21% greater yield load, and 27% greater ultimate load. Clinical Relevance:Adjustable knotless ASA cortical fixation is a viable alternative for transosseous quadriceps tendon repair that increases repair strength and reduces patellar tunnel drilling.

Background: Optimal placement of the glenosphere in reverse shoulder arthroplasty (rTSA) is a key component affecting postoperative range of motion (ROM) but remains a subject of ongoing research. The purpose of this study was to evaluate the relationship between three-dimensional (3D) glenosphere position and orientation relative to anatomic scapular landmarks and postoperative patient-reported outcomes and ROM following rTSA. Methods: A retrospective multicenter cohort study was conducted on primary rTSAs performed with a 135° humeral inlay component and a lateralized glenoid component between November 2016 and March 2022. Surgeries performed with a 3D plan and patient-specific transfer instrumentation with minimum 2-year clinical follow-up were included. Implant position was extracted from preoperative planning software, focusing on pin position (center of the glenosphere) and glenosphere diameter, version, and overhang relative to scapular anatomic landmarks. ROM and American Shoulder and Elbow Surgeons (ASES) scores were assessed at 2-year follow-up, with linear regression models utilized to analyze the relationships between preoperative and intraoperative variables and postoperative outcomes while adjusting for confounding variables. Results: A total of 75 rTSAs met the study criteria. For every 1 millimeter increase in glenosphere diameter, there was a 0.5 spinal level decrease in internal rotation (IR) spine (P ≤ .005) and a 2.5° decrease in forward flexion (P ≤ .005). For every 4° increase in baseplate retroversion, there was a 1 spinal level improvement in IR spine (P = .009). Superior tilt of the baseplate was associated with a decrease in internal rotation at 90° of abduction (3° decrease per 1° of increased superior tilt, P ≤ .001). ASES scores were also significantly affected, with a 3.5 point decrease per millimeter increase in glenosphere diameter (P ≤ .001), but improved by a 1 point per millimeter increase in pin-to-coracoid distance (P = .015). Conclusion: In patients with 3D planning and patient-specific instrumentation, smaller glenosphere diameter, increased baseplate retroversion, and avoidance of superior tilt improve IR after rTSA performed with a 135° humeral component and lateralized glenoid. A smaller glenosphere diameter and increased distance from the coracoid also improved ASES scores. This data suggests that with the use of a lateralized glenoid in rTSA, efforts should be made to increase the glenosphere distance from the coracoid, avoid a superior tilted positioning of the baseplate, and consider a smaller glenosphere when in between sizes.

BACKGROUND:Impingement-free range of motion (ROM) after reverse shoulder arthroplasty (rTSA) may depend on implant position and scapula anatomic parameters. The critical shoulder angle (CSA) is influenced by a combination of scapula parameters. The aim of this study was to evaluate whether the CSA has an influence on impingement-free ROM after rTSA in a virtual simulation using a Statistical Shape Model. MATERIALS AND METHODS:100 scapulae chosen from a database of 10,000 scapulae were used to generate a Statistical Shape Model. Modes corresponding to anatomical characteristics (size, CSA etc.) were defined. Five CSA models were obtained including a mean and 2 standard deviations (SDs) (CSA 32° [-2 SD], CSA 30° [-1 SD], CSA 27° [mean], CSA 25° [+1 SD], and CSA 23° [+2 SD]). A 39-mm glenosphere was virtually implanted in each model. The humeral side was kept consistent with the simulation of a 135° neck-shaft-angle component (Univers Revers, Arthrex Inc., Naples, FL, USA). Glenoid positioning parameters included (1) lateral offset (0-10 mm in 2-mm increments), (2) inferior offset (0, 2.5, 5, 7.5 mm), and (3) posterior offset (0, 2.5, 5 mm). External rotation (ER) at 0° and 60° of abduction and internal rotation (IR) at 60° of abduction were then analyzed for the different positioning parameters (inferior, posterior, and lateral offset) and the combination of 0 mm inferior and 2.5 posterior offset and lateralization from 0-10 mm, 2.5 mm inferior and 0 mm of posterior offset and lateralization (0-10 mm), and the combination of 2.5 mm inferior and 2.5 mm posterior offset and lateralization (0-10 mm). RESULTS:Lower CSA models showed higher ER 0° values (eg, 435% increase from CSA 32° to CSA 23° at 0 mm lateral, inferior, and posterior offset), while models with greater CSAs showed higher IR 60° values (eg, 505% increase from CSA SD 23° to CSA SD 32° at 0 mm lateral, inferior, and posterior offset). By lateralizing, ROM increased in all CSA models (eg, 884% increase from 0 mm to 10 mm lateralization for CSA 32° for ER 0°). Posterior positioning of 2.5 and 5 mm improved ER not IR. Maximal IR at 60° was achieved with no posterior, 2.5 mm of inferior offset, and lateralization between 2-6 mm according to the evaluated CSA. CONCLUSION:Specific CSA ranges require particular implant positioning strategies to optimize impingement-free ROM in rTSA. To achieve the maximal ROM combination of IR and ER in this simulation, 2.5 mm of inferior offset with no posterior offset and lateralization of 4 mm for CSA ≥30° and 6 mm for CSA SD ≤25° was required.

BACKGROUND:Despite advances in surgical technique and implant design, internal rotation (IR) after reverse total shoulder arthroplasty (rTSA) continues to be relatively unpredictable. The purpose of this study was to compare patient characteristics, use of 3-dimensional computed tomography (3D CT)-based preoperative planning, and postoperative implant position between patients with high or low IR after rTSA. METHODS:A retrospective review was performed of a multicenter prospectively collected database on patients who underwent primary rTSA (Univers Revers; Arthrex, Inc.) from 2016-2021 with a minimum 2-year follow-up. Patients were selected for a comparative analysis who either achieved high IR (T12 or better) or low IR (below the hip) postoperatively. Baseline demographics and postoperative radiographs were evaluated for association with IR. Implant position was assessed on radiographs for lateralization shoulder angle (LSA), distalization shoulder angle (DSA), inferior glenosphere overhang, and coracoid-to-glenosphere distance. Regression analyses were performed on component and clinical variables to assess for factors predictive of high vs. low IR. RESULTS:A total of 344 rTSAs were eligible, of which 98 patients met criteria for the high-IR group and 50 met criteria for the low-IR group. Decreased body mass index (BMI) (odds ratio [OR] 1.14, 95% confidence interval [CI] 1.01-1.30, P = .044), high preoperative IR (OR 1.30, 95% CI 1.02-1.66, P = .034), and surgery on the dominant arm (OR 5.38, 95% CI 1.31-22.1, P = .019) correlated with an increased odds of high IR. The use of 3D CT-based preoperative planning was associated with having high IR (OR 9.69, 95% CI 1.83-51.3, P = .008). Radiographically, increased DSA (OR 1.09, 95% CI 1.02-1.16, P = .012) and increased inferior glenoid overhang (OR 1.39, 95% CI 1.07-1.80, P = .013) were associated with a greater chance of being in the high-IR group. CONCLUSION:Although specific baseline patient characteristics influence the ability to obtain high IR after rTSA including increased preoperative IR, decreased BMI, and surgery on the dominant arm, there are several factors within the surgeon's control. The use of 3D CT-based preoperative planning greatly increases the odds of obtaining increased postoperative IR. More precisely, mindful implant positioning including inferior glenosphere overhang and slight distalization increased postoperative IR. Therefore, the use of 3D CT-based preoperative planning may be considered in order to carefully and consciously position the glenosphere to slightly increase distalization and inferior overhang in order to optimize IR. However, further evaluation with regard to 3D planned position and postoperative outcomes are required.

BACKGROUND:Acromial stress fractures (ASFs) after reverse total shoulder arthroplasty (rTSA) can have a devastating effect on a patient's overall function, causing decreased range of motion and patient satisfaction. The purpose of this study was to evaluate preoperative patient demographics and radiographic findings associated with risk for ASF after rTSA. METHODS:A retrospective review was performed on patients who underwent primary rTSA by a single surgeon between December 2011 and December 2022. Inclusion criteria were primary rTSA with minimum 6-month postoperative radiographs. Preoperative demographics, comorbidities, and radiographic factors (acromial thickness, critical shoulder angle, humeral cortical thickness, and acromiohumeral distance) were reviewed. Postoperative radiographs were all evaluated for the presence of ASF and classified according to the Levy classification. Univariate analyses followed by logistic regression analyses were performed to evaluate for significant risk factors. A Bonferroni correction was then performed. RESULTS:A total of 757 rTSAs were included and 58 (7.7%) ASFs identified. ASFs were identified at a median of 14 weeks postoperatively. Across the entire cohort, including both male and female patients, multiple factors including lower body mass index, inflammatory arthritis, and decreased acromial thickness were identified as initially being correlated with ASF. Among females, the presence of inflammatory arthritis, the use of preoperative osteoporosis medications, humeral cortical thickness, and acromial thickness were initially identified as increasing the risk of ASF. For males, surgery on the dominant arm and lower body mass index were initially identified as increasing the risk of ASF. After a Bonferroni correction was completed and the P value representing significance was set at P < .0025, only the presence of inflammatory arthritis in females was found to be statistically significant (odds ratio: 4.87, 95% confidence interval: 2.16-10.96, P < .001). CONCLUSION:This study points to multiple preoperative patient characteristics that showed initial correlation with an increased risk of ASF and demonstrates the importance of future study. After the statistical significance was revised and set at P < .0025, females with inflammatory arthritis are associated with increased risk of ASF after rTSA. These findings suggest that overall patient health and fragility may be more predictive of ASF rather than preoperative radiographic characteristics that were studied. We propose that further study of other factors, such as implant position, patient nutrition, and postoperative rehabilitation parameters, be performed to determine their impact on ASF risk.

Background: The degree of constraint of the humeral liner is a key determinant of the stability of reverse total shoulder arthroplasty (rTSA). However, it remains largely unknown to what extent the degree of constraint affects range of motion (ROM). Purpose: To analyze the influence of various liner types on simulated ROM following virtual rTSA implantation in patients with different posture types. Methods: The CT scans of 48 consecutive patients scheduled for rTSA implantation were utilized to create patient-specific 3D bone models. For all cases, six shoulder surgeons independently virtually implanted a rTSA (lateralized 135° semi-inlay design) according to their respective preferences using an experimental surgical planning software. ROM was determined simulating posture type A (upright posture), B (intermediate), and C (kyphotic posture) utilizing a standard, constrained, and high mobility liner, resulting in a total of 2592 different rTSA configurations. Subgroup analyses were performed to determine the influence of the degree of constraint on simulated ROM across the three posture types. Results: Total ROM decreased with increasing liner constraint from a median of 611° [interquartile range 522° to 666°] with high mobility liners to 512° [IQR 441-570°] with standard liners to 411° [IQR 322-470°] with constrained liners (p < 0.01). For all posture types, the use of a high mobility liner led to a significant increase in ROM in all planes except abduction, except for flexion in posture type A. Constrained liners significantly decreased ROM in all planes except abduction in posture type A. For posture type A, the greatest increase in ROM due to more mobile liners was observed in extension (+17°; p <0.01) and internal rotation (+17°; p <0.01), while the greatest decrease (due to more constrained liners) was also seen in extension (-34°; p <0.01). In posture type B, the greatest increase in ROM occurred in adduction (+19°; p <0.01), whereas the greatest decrease was in high internal rotation (-28°; p <0.01). Similarly, for posture type C, the greatest increase in ROM was observed in adduction (+30°; p <0.01), while the greatest decrease was in high internal rotation (-21°; p <0.01). Conclusion: While in posture types B and C, high mobility liners improved particularly adduction and constrained liners decreased high internal rotation, in posture type A extension and internal rotation could be improved most prominently while extension was most prominently decreased by a constrained liner.

BACKGROUND:Considering limb dominance (LD) may be valuable when utilizing limb symmetry index (LSI) when assessing patients after anterior cruciate ligament reconstruction (ACLR). HYPOTHESIS:Patients will have better performance-based outcomes when index ACLR occurred on the dominant limb (DL) compared with the nondominant limb (NDL). STUDY DESIGN:Observational cross-sectional study. LEVEL OF EVIDENCE:Level 3. METHODS:A total of 279 patients (49.1% female, 20.83 ± 5.23 years; 48% DL surgery) completed a laboratory visit (7.65 ± 1.65 months post-ACLR) assessing LD influence on knee extension and flexion peak torque, center of pressure (COP) distance and velocity, and hop performance. LD was defined as the preferred limb to kick a soccer ball. LSI variables were converted to indicator variables and categorized as "Pass" or "Fail" based on LSI ≥ 90%. RESULTS:Patient LD and isometric knee extension LSI Pass status were significantly associated (χ2 = 10.09; P = 0.001). No additional associations were found between LD and other LSI Pass status variables (P > 0.05). Patients with DL ACLR demonstrated more symmetric knee extension peak torque (P < 0.001, d = 0.42) and 6-meter hop (P = 0.02, d = 0.25) outcomes; NDL was more symmetric during COP distance tests (P = 0.03, d = 0.40). No differences were observed between LD and raw strength or balance measures (P > 0.05). Patients with ACLR on their NDL jumped farther on their contralateral limb for triple-hop (P = 0.03, d = 0.23) but not single-hop (P > 0.05) distance. CONCLUSION:LD appears to influence isometric knee LSI in patients post-ACLR; patients with surgery on their DL achieved higher symmetry and a greater rate of LSI Pass success for knee extension strength. CLINICAL RELEVANCE:Addressing differences in recovery patterns between DL and NDL may improve rehabilitation precision and guide return-to-activity timelines after ACLR.

Background:There has been increased interest in lateral extra-articular procedures, such as anterolateral ligament reconstruction (ALLR) or lateral extra-articular tenodesis (LET), to reduce anterolateral rotation instability of the knee after anterior cruciate ligament reconstruction (ACLR). Despite promising surgical outcomes with these techniques, their impact on knee strength recovery is unknown. Hypothesis:Patients undergoing lateral extra-articular procedures at the time of ACLR would have impaired thigh muscle strength at 6 to 9 months after surgery. Study Design:Cohort study; Level of evidence, 3. Methods:Adolescent patients who had undergone primary unilateral ACLR with lateral extra-articular augmentation between 2017 and 2023 were identified. Patients were included if they were aged between 12 and 20 years at the time of surgery and had completed an isokinetic strength assessment at 6 to 9 months after surgery. A total of 104 participants (mean age, 16.5 ± 1.7 years; 63 female) were included in this analysis: 25 who underwent ACLR+ALLR, 17 who underwent ACLR+LET, and 62 who underwent isolated ACLR. Isokinetic knee extension and flexion strength normalized to body weight, as well as the bilateral limb symmetry index (LSI), were assessed. One-way analysis of variance and analysis of covariance were used to compare differences between surgical techniques. Results:After adjusting for age, graft type, and time since surgery, the ACLR+LET (1.36 ± 0.52 N·m/kg) and ACLR+ALLR (1.61 ± 0.53 N·m/kg) groups had significantly less involved limb knee extension strength (P = .025), uninvolved limb knee extension strength (P = .046), and LSI for knee extension strength (P = .040) compared to the isolated ACLR group. There were no differences between the 3 groups regarding involved limb knee flexion strength (P = .222) or uninvolved limb knee flexion strength (P = .984), but the isolated ACLR group displayed a greater LSI for knee flexion strength (96.6% ± 17.8%; P = .012). Conclusion:The addition of lateral extra-articular procedures at the time of ACLR was associated with decreased quadriceps strength at 6 to 9 months after ACLR. While lateral extra-articular procedures may enhance knee rotary stability after ACLR, prolonged rehabilitation may be needed to re-establish adequate quadriceps strength before return to sports.

BACKGROUND:Anatomic total shoulder arthroplasty (aTSA) is a well-described technique for addressing glenohumeral osteoarthritis. Little has been written on outcomes for newer stemless humeral implants in older patients, with none looking specifically at an implant relying on screw fixation. The purpose of this study is to evaluate the clinical and radiographic outcomes for patients over 70 years of age undergoing aTSA with the Eclipse (Arthrex Inc., Naples, FL, USA) stemless humeral component. METHODS:A retrospective review using a multicenter shoulder arthroplasty registry was performed evaluating all patients over 70 years of age who underwent aTSA with a stemless humeral implant for a diagnosis of glenohumeral osteoarthritis and had a minimum follow-up of 2 years. Thirty-seven patients met the study criteria and were matched for comparative analysis to 37 patients 65 years and younger. Outcome scores were obtained preoperatively and at 2 years postoperatively using the visual analog scale, Constant-Murley, American Shoulder and Elbow Surgeons (ASES), and Western Ontario Osteoarthritis Index (WOOS) scores. The percentage of patients in each group who exceeded the Minimal Clinically Important Difference (MCID) for the ASES and WOOS was reported. When available, postoperative radiographs were evaluated for the presence of radiolucent lines and calcar resorption. RESULTS:There was a statistically significantly higher preoperative WOOS score in the older patient group; otherwise, there was no statistical difference between the 2 groups in regard to baseline scores or range of motion. At 2-year follow-up, older patients were noted to have significantly better visual analog scale, ASES, WOOS, and Constant-Murley scores than younger patients (P < .05). For the ASES, all patients over the age of 70 years achieved MCID compared with 84% of those 65 years and younger (P = .011), whereas for the WOOS, 100% of older patients achieved MCID compared with 86% of those in the control group (P = .022). Postoperative range of motion was generally not different between the 2 groups, although older patients had better active internal rotation at 90° of abduction (P = .002). Partial calcar resorption was noted in 1 patient in each age group. Radiolucent lines were noted in 2 patients over the age of 70 years and 1 patient 65 years or younger. DISCUSSION:Patients over the age of 70 years with glenohumeral osteoarthritis undergoing aTSA with a stemless humeral component have equivalent, if not better, outcomes when compared with younger patients. Age alone does not appear a limitation for stemless aTSA.

BACKGROUND:Preoperative scapular neck length (SNL) varies widely due to anatomical factors and pathologic glenoid wear. A short SNL can lead to early impingement, decreased range of motion (ROM), and increased rates of scapular notching after reverse shoulder arthroplasty (rTSA). Glenoid-sided implant lateralization can avoid these issues, but it is unclear how much is necessary for varying SNLs. The objective was to use a statistical shape model, varying SNL, to evaluate impingement-free rotational ROM across different glenoid positions and lateralizations. METHODS:A total of 100 scans were randomly chosen from a clinical database of over 10,000 shoulder computed tomography scans uploaded for shoulder arthroplasty preoperative planning. These 100 scans were utilized to create and validate a statistical shape model. Modes corresponding to scapular size and scapular neck angle were identified as producing the greatest variance in SNL, from which the mean SNL and 2 standard deviations (positive and negative) were evaluated for the study. For each scapula, a single glenosphere diameter (33-42 mm) was selected by a consensus of 3 surgeons. A 135° NSA inlay humeral prosthesis was utilized for all simulations (Arthrex Univers rTSA). Impingement-free rotational ROM was then assessed for each of the 5 scapulae for the following virtual implantation variables: lateralization (0-12 mm), inferior glenosphere eccentricity (0-2.5 mm), and posterior glenosphere eccentricity (0-2.5 mm). RESULTS:Both SNL and glenoid lateralization had significant contributions to rotational ROM. Progressive glenoid lateralization improved external rotation at 0° of abduction (ER0), external rotation at 60° of abduction (ER60), and internal rotation at 60° (IR60) across all 5 standard deviations of SNL. IR60 was greatest for the longest SNL, and the value of progressive glenoid lateralization was the greatest for improving IR60 for the shortest SNL, where 6 mm of lateralization achieved maximum IR60. ER0 was greatest for the shortest SNL, and the value of glenoid lateralization for ER0 was not seen for the longest SNL until >4 mm of lateralization. ER60 was largely not influenced by lateralization or SNL, where 2-4 mm of lateralization maximized sufficiently. CONCLUSIONS:Both SNL and glenoid implant lateralization influence rotational ROM after rTSA with a 135° NSA and should be considered as covariates when determining appropriate implant selection and positioning. For smaller SNL, 6 mm of implant lateralization is needed to maximize impingement-free internal rotation. For larger SNL, a minimum 6 mm of implant lateralization is needed to maximize impingement-free external rotation.