Treatment of Unfixable Inferior Pole Fractures of the Patella Using an All-Suture Internal Fixation Technique.

Inferior pole fractures of the patella are a type of patellar fracture that has various complexities. Most current techniques are associated with hardware-related complications, which is one of the main concerns when treating this complex fracture. We present a new technique that does not require metal implant removal, causes little to no irritation of the quadriceps muscle, and provides strong fixation that allows for early range of motion postoperatively.

Outcomes of total shoulder arthroplasty in patients with prior anterior shoulder instability: minimum 5-year follow-up.

BACKGROUND: Patients with a history of anterior shoulder instability (ASI) commonly progress to glenohumeral arthritis or even dislocation arthropathy and often require total shoulder arthroplasty (TSA). The purposes of this study were to (1) report patient-reported outcomes (PROs) after TSA in patients with a history of ASI, (2) compare TSA outcomes of patients whose ASI was managed operatively vs. nonoperatively, and (3) report PROs of TSA in patients who previously underwent arthroscopic vs. open ASI management. METHODS: Patients were included if they had a history of ASI and had undergone TSA ≥5 years earlier, performed by a single surgeon, between October 2005 and January 2017. The exclusion criteria included prior rotator cuff repair, hemiarthroplasty, or glenohumeral joint infection before the index TSA procedure. Patients were separated into 2 groups: those whose ASI was previously operatively managed and those whose ASI was treated nonoperatively. This was a retrospective review of prospective collected data. Data collected was demographic, surgical and subjective. The PROs used were the American Shoulder and Elbow Surgeons score, Single Assessment Numerical Evaluation score, QuickDASH (Quick Disabilities of the Arm, Shoulder and Hand) score, and 12-item Short Form physical component score. Failure was defined as revision TSA surgery, conversion to reverse TSA, or prosthetic joint infection. Kaplan-Meier survivorship analysis was performed. RESULTS: This study included 36 patients (27 men and 9 women) with a mean age of 56.4 years (range, 18.8-72.2 years). Patients in the operative ASI group were younger than those in the nonoperative ASI group (50.6 years vs. 64.0 years, P < .001). Operative ASI patients underwent 10 open and 11 arthroscopic anterior stabilization surgical procedures prior to TSA (mean, 2 procedures; range, 1-4 procedures). TSA failure occurred in 6 of 21 patients with operative ASI (28.6%), whereas no failures occurred in the nonoperative ASI group (P = .03). Follow-up was obtained in 28 of 30 eligible patients (93%) at an average of 7.45 years (range, 5.0-13.6 years). In the collective cohort, the American Shoulder and Elbow Surgeons score, Single Assessment Numerical Evaluation score, QuickDASH (Quick Disabilities of the Arm, Shoulder and Hand) score, and 12-item Short Form physical component score significantly improved, with no differences in the postoperative PROs between the 2 groups. We found no significant differences when comparing PROs between prior open and prior arthroscopic ASI procedures or when comparing the number of prior ASI procedures. Kaplan-Meier analysis demonstrated a 79% 5-year survivorship rate in patients with prior ASI surgery and a 100% survivorship rate in nonoperatively managed ASI patients (P = .030). CONCLUSION: At mid-term follow-up, patients with a history of ASI undergoing TSA can expect continued improvement in function compared with preoperative values. However, TSA survivorship is decreased in patients with a history of ASI surgery compared with those without prior surgery.

Utility of Talus Osteochondral Allograft Augmentation for Varying Hill-Sachs Lesion Sizes: A Cadaveric Study.

Background: Humeral head reconstruction with fresh osteochondral allografts (OCA) serves as a potential treatment option for anatomic reconstruction. More specifically, talus OCA is a promising graft source because of its high congruency with a dense cartilaginous surface. Purpose: To analyze the surface geometry of the talus OCA plug augmentation for the management of shoulder instability with varying sizes of Hill-Sachs lesions (HSLs). Study Design: Controlled laboratory study. Methods: Seven fresh-frozen cadaveric shoulders were tested in this study. The humeral heads were analyzed using actual patients' computed tomography scans. Surface laser scan analysis was performed on 7 testing states: (1) native state; (2) small HSL; (3) talus OCA augmentation for small HSL; (4) medium HSL; (5) talus OCA augmentation for medium HSL; (6) large HSL; and (7) talus OCA augmentation for large HSL. OCA plugs were harvested from the talus allograft and placed in the most medial and superior aspect of each HSL lesion. Surface congruency was calculated as the mean absolute error and the root mean squared error in the distance. A 1-way repeated-measures analysis of variance was performed to evaluate the effects of the difference in the HSL size and associated talus OCA plugs on surface congruency and the HSL surface area. Results: The surface area analysis of the humeral head with the large (1469 ± 75 mm2), medium (1391 ± 81 mm2), and small (1230 ± 54 mm2) HSLs exhibited significantly higher surface areas than the native state (1007 ± 88 mm2; P < .001 for all sizes). The native state exhibited significantly lower surface areas as compared with after talus OCA augmentation for large HSLs (1235 ± 63 mm2; P < .001) but not for small or medium HSLs. Talus OCA augmentation yielded improved surface areas and congruency after treatment in small, medium, and large HSLs (P < .001). Conclusion: Talus OCA plug augmentation restored surface area and congruency across all tested HSLs, and the surface area was best improved with the most common HSLs-small and medium. Clinical Relevance: Talus OCA plugs may provide a viable option for restoring congruity of the shoulder in patients with recurrent anterior glenohumeral instability and an HSL.

Increased Posterior Tibial Slope Increases Force on the Posterior Medial Meniscus Root.

BACKGROUND: Posterior medial meniscus root (PMMR) tears have been associated with increased posterior tibial slope, but this has not been fully evaluated biomechanically. In addition, the effects of knee flexion and rotation on the PMMR are not well understood biomechanically because of technological testing limitations. A novel multiaxial force sensor has made it possible to elucidate answers to these questions. PURPOSE: (1) To determine if increased posterior tibial slope results in increased posterior shear force and compression on the PMMR, (2) to evaluate how knee flexion angle affects PMMR forces, and (3) to assess how internal and external rotation affects force at the PMMR. STUDY DESIGN: Controlled laboratory study. METHODS: Ten fresh-frozen cadaveric knees were tested in all combinations of 3 posterior tibial slopes and 4 flexion angles. A multiaxial force sensor was connected to the PMMR and installed below the posterior tibial plateau maintaining anatomic position. The specimen underwent a 500-N compression load followed by a 5-N·m internal torque and a 5-N·m external torque. The magnitude and direction of the forces acting on the PMMR were measured. RESULTS: Under joint compression, an increased tibial slope significantly reduced the tension on the PMMR between 5° and 10° (from 13.5 N to 6.4 N), after which it transitioned to a significant increase in PMMR compression, reaching 7.6 N at 15°. Under internal torque, increased tibial slope resulted in 4.7 N of posterior shear at 5° significantly changed to 2.0 N of anterior shear at 10° and then 8.2 N of anterior shear at 15°. Under external torque, increased tibial slope significantly decreased PMMR compression (5°: 8.9 N; 10°: 4.3 N; 15°: 1.1 N). Under joint compression, increased flexion angle significantly increased medial shear forces of the PMMR (0°, 3.8 N; 30°, 6.2 N; 60°, 7.3 N; 90°, 8.4 N). Under internal torque, 90° of flexion significantly increased PMMR tension from 2.3 N to 7.5 N. Under external torque, 30° of flexion significantly increased PMMR compression from 4.7 N to 12.2 N. CONCLUSION: An increased posterior tibial slope affects compression and anterior shear forces at the PMMR. An increased flexion angle affects compression, tension, and medial shear forces at the PMMR. CLINICAL RELEVANCE: The increase in compression and posterior shear force when the knee is loaded in compression may place the PMMR under increased stress and risk potential failure after repair. This study provides clinicians with information to create safer protocols and improve repair techniques to minimize the forces experienced at the PMMR.

Biomechanical Analysis Evaluating Meniscal Extrusion After Knotless Suture Anchor Fixation for Segmental Medial Meniscal Allograft Transplantation.

Background: Segmental medial meniscal allograft transplantation (MAT) has been shown to restore knee biomechanics; however, stable fixation of the transplantation is critical to avoid extrusion and maximize healing. Purpose: To evaluate the degree of meniscal extrusion and biomechanical function of segmental medial MAT performed with meniscocapsular sutures versus repair augmentation with knotless suture anchors. Study Design: Controlled laboratory study. Methods: Segmental midbody medial meniscectomy and subsequent segmental medial MAT were performed on 10 fresh-frozen cadaveric knees. The knees were then loaded in a dynamic tensile testing machine to 1000 N for 60 seconds at 0°, 30°, 60°, and 90° of flexion, and 4 conditions were tested: (1) intact, (2) segmental defect, (3) inside-out segmental repair, and (4) anchor plus inside-out segmental repair of the medial MAT. Meniscal extrusion was measured using high-fidelity ultrasound imaging. The mean contact area and the mean and peak contact pressures were assessed with submeniscal pressure-mapping sensors. Data from testing conditions were compared with 2-way repeated-measures analysis of variance, with pairwise comparison using the Bonferroni method. Results: At 90° of flexion, the segmental defect state showed a higher degree of meniscal extrusion compared with all other states (P ≤ .012). There was no difference in the degree of meniscal extrusion between the intact state and the inside-out repair or anchor plus inside-out segmental repair states at all knee flexion angles (P > .05). There was no significant difference in the mean and peak contact pressures among the 4 states at all flexion angles except that at 0° of knee flexion there was significantly lower peak contact pressure at the medial compartment after anchor plus inside-out segmental repair compared with the segmental defect state (P = .048). Conclusion: Meniscal extrusion was not significantly increased at any flexion angle after segmental resection. The addition of knotless anchors did not improve meniscal extrusion or contact pressures/area compared with capsular repair alone. The addition of knotless anchors did improve contact mechanics from the segmental defect state, but only at 0° of flexion. Clinical Relevance: The addition of knotless suture anchors to segmental meniscal transplantation increased stabilization of the meniscus at full extension compared with repair with sutures alone. This increased stabilization may lead to better long-term outcomes.

Meniscotibial Ligament Insufficiency Increases Force on the Posterior Medial Meniscus Root.

BACKGROUND: Posterior medial meniscus root (PMMR) tears are a challenge to assess and treat. However, the forces sustained at the PMMR are yet to be fully characterized. In addition, it has been shown that meniscotibial ligament (MTL) injuries happen before PMMR tears, suggesting that insufficiency of the MTL results in a change of forces acting on the PMMR. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate the 3-dimensional forces acting on the PMMR in the intact, MTL cut, and MTL tenodesis states. It was hypothesized that the MTL cut state would increase medial shear forces seen at the PMMR, whereas the medial shear force in the MTL tenodesis state would return PMMR forces to that of the intact state. STUDY DESIGN: Controlled laboratory study. METHODS: Ten fresh-frozen cadaveric knees were tested in 3 states (intact, MTL cut, and tenodesis). A 3-axis load cell was installed below the posterior tibial plateau and attached to the enthesis of the PMMR. The specimen was mounted to a load frame that applied an axial load, an internal torque, and an external torque. The amount of compression-tension, mediolateral shear force, and anteroposterior shear force acting on the PMMR was measured. RESULTS: When the joint was loaded in compression, the MTL cut state significantly increased compression of the PMMR (P = .0368). The tenodesis state did not significantly restore forces of the PMMR (P = .008). When the joint was loaded in external torque, the MTL cut state significantly increased compression (P < .0001) and significantly decreased anterior shear on the PMMR (P = .0003). The tenodesis state did not significantly restore forces on the PMMR to the intact state (P < .0001). Increased flexion angle significantly increased medial shear forces of the PMMR when the joint was loaded in compression (P < .007 at every angle). CONCLUSION: When evaluated biomechanically, MTL insufficiency resulted in increased compressive force at the PMMR. A single-anchor centralization procedure did not restore PMMR forces to that of the intact state. Increased knee flexion angle resulted in increased medial shear force on the PMMR. CLINICAL RELEVANCE: The findings in this study provide clinicians information on PMMR forces when the MTL is disrupted. These data can aid in the decision-making for adding an MTL repair to augment PMMR repairs.

Patient-Specific Instrumentation for Medial Closing Wedge Distal Femoral Osteotomy With Patellar Osteochondral Allograft.

The primary indications for performing a medial closing wedge distal femoral osteotomy are valgus knee malalignment, lateral knee compartment overload, lateral meniscus insufficiency, and/or lateral compartment osteoarthritis or cartilage damage. Without correction of this malalignment, there is an increased risk for chondral damage in the lateral and patellofemoral compartment of the knee. The optimal candidates for this procedure are young, active individuals with moderate to severe arthritis in the lateral compartment. Recently, preoperative planning for high tibial and distal femoral osteotomies (HTOs and DFOs) using 3-dimensional (3D) patient-specific instrumentation (PSI) has increased in popularity. Successful patient outcomes have been reported using this technique. This Technical Note illustrates our preferred technique that uses 3D PSI in addition to a patellar OCA transplant when treating a symptomatic cartilage lesion associated with genu valgum.

Ulnar Collateral Ligament (UCL) Reconstruction With Proximal Single-Tunnel Suspensory Fixation.

Ulnar collateral ligament (UCL) reconstruction of the medial elbow is considered to be the gold standard for treating valgus instability seen in overhead throwing athletes. The first UCL construction was performed by Frank Jobe in 1974, and this procedure has evolved over time to include multiple techniques that improved the biomechanical strength of the graft fixation and maximize the rate of return to athletic competition for these patients. The most common UCL-reconstruction technique used today is the docking technique. The purpose of this Technical Note is to describe our technique, including pearls and pitfalls, which combines the many advantages of the docking technique with a proximal single-tunnel suspensory fixation technique. This method allows for optimal tensioning of the graft, allowing for secure fixation that relies on metal implants as opposed to tying sutures over a proximal bone bridge.

Scapular dyskinesis after treatment of proximal humerus fracture, a 3-dimensional motion analysis and clinical outcomes.

BACKGROUND: The alteration of scapular kinematics can predispose patients to shoulder pathologies and dysfunction. Previous literature has associated various types of shoulder injuries with scapular dyskinesis, but there are limited studies regarding the effect that proximal humeral fractures (PHFs) have on scapular dyskinesis. This study aims to determine the change in scapulohumeral rhythm following treatment of a proximal humerus fracture as well as differences in shoulder motion and functional outcomes among patients who presented with or without scapular dyskinesis. We hypothesized that differences in scapular kinematics would be present following treatment of a proximal humerus fracture, and patients who presented with scapular dyskinesis would subsequently have inferior functional outcome scores. METHODS: Patients treated for a proximal humerus fracture from May 2018 to March 2021 were recruited for this study. The scapulohumeral rhythm and global shoulder motion were determined using a 3-dimensional motion analysis (3DMA) and the scapular dyskinesis test. Functional outcomes were then compared among patients with or without scapular dyskinesis, including the SICK (scapular malposition, inferomedial border prominence, coracoid pain and malposition, and dyskinesis of scapular movement) Scapula Rating Scale, the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), the visual analog scale (VAS) for pain, and the EuroQol-5 Dimension 5-Level questionnaire (EQ-5D-5L). RESULTS: Twenty patients were included in this study with a mean age of 62.9 ± 11.8 years and follow-up time of 1.8 ± 0.2 years. Surgical fixation was performed in 9 of the patients (45%). Scapular dyskinesis was present in 50% of patients (n = 10). There was a significant increase in scapular protraction on the affected side of patients with scapular dyskinesis during abduction of the shoulder (P = .037). Additionally, patients with scapular dyskinesis demonstrated worse SICK scapula scores (2.4 ± 0.5 vs. 1.0 ± 0.4, P = .024) compared to those without scapular dyskinesis. The other functional outcome scores (ASES, VAS pain scores, and EQ-5D-5L) showed no significant differences among the 2 groups (P = .848, .713, and .268, respectively). CONCLUSIONS: Scapular dyskinesis affects a significant number of patients following treatment of their PHFs. Patients presenting with scapular dyskinesis exhibit inferior SICK scapula scores and have more scapular protraction during shoulder abduction compared to patients without scapular dyskinesis.

Reanalysis of the Posterior Oblique Ligament: Quantitative Anatomy, Radiographic Markers, and Biomechanical Properties.

Background: The posterior oblique ligament (POL) is the largest structure of the posteromedial knee that is at risk of injury in conjunction with the medial collateral ligament (MCL). Its quantitative anatomy, biomechanical strength, and radiographic location have not been assessed in a single investigation. Purpose: To evaluate the 3-dimensional and radiographic anatomy of the posteromedial knee and the biomechanical strength of the POL. Study Design: Descriptive laboratory study. Methods: Ten nonpaired fresh-frozen cadaveric knees were dissected and medial structures were elevated off bone, leaving the POL. The anatomic locations of the related structures were recorded with a 3-dimensional coordinate measuring machine. Anteroposterior and lateral radiographs were taken with radiopaque pins inserted into the pertinent landmarks, and the distances between the collected structures were calculated. Each knee was then mounted to a dynamic tensile testing machine, and pull-to-failure testing was performed to record the ultimate tensile strength, stiffness, and failure mechanism. Results: The POL femoral attachment was a mean of 15.4 mm (95% CI, 13.9-16.8 mm) posterior and 6.6 mm (95% CI, 4.4-8.8 mm) proximal to the medial epicondyle. The tibial POL attachment center was a mean of 21.4 mm (95% CI, 18.1-24.6 mm) posterior and 2.2 mm (95% CI, 0.8-3.6 mm) distal to the center of the deep MCL tibial attachment and a mean of 28.6 mm (95% CI, 24.4-32.8 mm) posterior and 41.9 mm (95% CI, 36.8-47.0 mm) proximal to the center of the superficial MCL tibial attachment. On lateral radiographs, the femoral POL was a mean of 17.56 mm (95% CI, 14.83-21.95 mm) distal to the adductor tubercle and 17.32 mm (95% CI, 14.6-21.7 mm) posterosuperior to the medial epicondyle. On the tibial side, the center of the POL attachment was a mean of 4.97 mm (95% CI, 3.85-6.79 mm) distal to the joint line on anteroposterior radiographs and 6.34 mm (95% CI, 5.01-8.48 mm) distal to the tibial joint line on lateral radiographs, at the far posterior tibial aspect. The biomechanical pull-to-failure demonstrated a mean ultimate tensile strength of 225.2 ± 71.0 N and a mean stiffness of 32.2 ± 13.1 N. Conclusion: The anatomic and radiographic locations of the POL and its biomechanical properties were successfully recorded. Clinical Relevance: This information is useful to better understand POL anatomy and biomechanical properties as well as to clinically address an injury with repair or reconstruction.

Biomechanical comparison of ulnar collateral ligament reconstruction with single-tunnel proximal suspensory fixation versus modified docking technique.

Background: Despite technical advancement, elbow ulnar collateral ligament (UCL) reconstruction is a challenging procedure due to the limitations regarding the challenging tunnel placement and potential injury to the ulnar nerve. Furthermore, current techniques for reconstruction and repair are inferior functionally and biomechanically when compared to native UCL tissue. A modified docking technique using a single-tunnel proximal suspensory fixation may reduce complications and potentially provide a technique for UCL reconstruction that is biomechanically superior. Decreasing the number of bone tunnels decreases the number of places that bone tear through could occur. The purpose was to evaluate and compare the biomechanical performances for 2 elbow UCL reconstruction techniques: (1) standard docking technique (SD) and (2) a proximal single tunnel (PST) technique using a suspensory fixation. We hypothesized that the PST technique would be biomechanically superior to the SD technique. Methods: Twelve matched pairs of cadaveric elbows were dissected and fixed at 70 degrees for biomechanical testing. Gracilis grafts were used for a docking reconstruction and the modified reconstruction with a PST suspensory fixation. A cyclic valgus torque protocol was used to precondition specimens for either reconstruction technique and the ulnohumeral gapping was then assessed. Following gapping measurements, postsurgical specimens underwent a valgus rotation applied at a rate of 5°/s until the anterior band of the UCL failed or fracture occurred. Ultimate load to failure, stiffness, and mode of failure were recorded. Results: There were no statistical differences between the two groups. Mean rotational stiffness of the SD (2.3 ± 0.6 Nm/deg) compared to the PST (1.9 ± 0.7 Nm/deg) (P = .41) and mean ultimate failure torque of the SD (30.5 ± 9.2 Nm) compared to the PST (30.9 ± 8.6 Nm) (P = .86) were similar. There was also no statistically significant difference (P = .83) when comparing the native UCL ulnohumeral gapping (6.0 ± 2.0 mm) to the mean ulnohumeral gapping of the SD reconstruction (6.0 ± 1.8 mm). Conclusions: This study compares the biomechanical strength of elbow UCL reconstructions performed using the SP technique to that of a PST technique. Among all tested parameters, including ultimate failure torque, stiffness, and ulnohumeral gapping, there were no statistically significant differences between the 2 techniques.

Direct measurement of three-dimensional forces at the medial meniscal root: A validation study.

The posterior medial meniscal root (PMMR) experiences variable and multiaxial forces during loading. Current methods to measure these forces are limited and fail to adequately characterize the loads in all three dimensions at the root. Our novel technique resolved these limitations with the installation of a 3-axis sensing construct that we hypothesized would not affect contact mechanics, would not impart extraneous loads onto the PMMR, would accurately measure forces, and would not deflect under joint loads. Six cadaveric specimens were dissected to the joint capsule and a sagittal-plane, femoral condyle osteotomy was performed to gain access to the root. The load sensor was placed below the PMMR and was validated across four tests. The contact mechanics test demonstrated a contact area precision of 44 mm2 and a contact pressure precision of 5.0 MPa between the pre-installation and post-installation states. The tibial displacement test indicated an average bone plug displacement of < 1 mm in all directions. The load validation test exhibited average precision values of 0.7 N in compression, 0.5 N in tension, 0.3 N in anterior-posterior shear, and 0.3 N in medial-lateral shear load. The bone plug deflection test confirmed < 2 mm of displacement in any direction when placed under a load. This is the first study to successfully validate a technique for measuring both magnitude and direction of forces experienced at the PMMR. This validated method has applications for improving surgical repair techniques and developing safer rehabilitation and postoperative protocols that decrease root loads.

Implant-dependent behavior of tunnel widening and clavicular button migration after arthroscopic-assisted treatment of acromioclavicular joint instabilities.

INTRODUCTION: Despite ongoing discussions for the previous few decades, there is still no consensus regarding the optimal surgical technique for acromioclavicular joint instabilities. The purpose of this study was to determine the impact of various implant materials following arthroscopically assisted stabilization of acromioclavicular joint instabilities on tunnel widening and implant migration. We hypothesized an implant-dependent behavior for tunnel widening and implant migration with differences when comparing acute and chronic acromioclavicular joint instabilities. METHODS: This study compared 105 patients with acromioclavicular joint instabilities that were managed operatively with coracoclavicular double button constructs. Two of the groups containing acute cases were treated with either a double button construct with a wire (TR) or a tape (D) as a central pillar. The two groups with chronic cases were either treated with a wire (T+) or tape D+ as a central pillar and additional hamstring tendon augmentation (+). One central transclavicular-transcoracoidal drill channel was made in the acute cases, while additional medial and lateral drill channels to augment the central pillar with the hamstring tendon were made. The central drill channel in all cases and the medial/lateral drill channels in chronic cases were subsequently radiologically analyzed immediately postoperatively and at follow-up. Following this, additional radiological analysis of the implant migration of the clavicular button took place. RESULTS: All groups showed significant tunnel widening of the central drill channel at follow-up (p ≤ 0.001). The TR+ technique demonstrated significant widening in both the medial (p ≤ 0.001) and lateral (p ≤ 0.001) drill channels. The D and D+ group displayed significant higher rates of clavicular button migration to a cortical and intraosseous level (p ≤ 0.002). CONCLUSION: Tunnel widening and implant migration following arthroscopically assisted management of acromioclavicular joint instabilities are dependent on the chosen implant. The stable tape showed a significantly increased degree of tunnel widening with respect to the central drill channel in comparison with the wire. In contrast, a higher degree of load capacity of the tape ultimately favors a protected intraosseous graft healing for chronic cases, which leads to less tunnel widening of the medial and lateral drill channel. Finally, the D/D+ implant groups showed higher rates of implant migration due to lower contact surface area of the implant at the upper clavicular cortex.

Treatment of the 'The Naked Humeral Head': Repair of Supraspinatus Avulsion, Subscapularis Tear, and Humeral Avulsion of the Glenohumeral Ligament.

A humeral avulsion of the glenohumeral ligament, or HAGL, lesion is a rare yet debilitating shoulder injury, which can lead to recurrent instability, pain, and overall shoulder dysfunction. The diagnosis is often difficult, requiring both high clinical suspicion, as well as identification on magnetic resonance imaging. In patients with an anterior HAGL, repair often requires an open approach. In extremely rare circumstances, the initial traumatic event that causes a HAGL can also cause disruption of the supraspinatus and subscapularis insertions on the humeral head. We have termed this the "naked humeral head". The purpose of this technical note is to describe our preferred technique to surgically treat the naked humeral head by repairing a supraspinatus avulsion fracture, HAGL lesion, and complete subscapularis tear.

Anterior to Posterior Bone Plug Suture Tunnels Provide Optimal Biomechanics for Bone-Patellar Tendon-Bone Anterior Cruciate Ligament Graft.

Purpose: To evaluate different bone-patellar tendon-bone (BPTB) plug suture configurations for pull through strength, stiffness, and elongation at failure in a biomechanical model of suspensory fixation. Methods: Forty nonpaired, fresh-frozen human cadaveric BPTB allografts with an average age of 65.6 years were tested. Tensile testing was performed with the use of a custom-designed fixture mounted in a dynamic tensile testing machine. A preload of 90 N was applied to the graft and held for 5 minutes. Following this, a tensile load-to-failure test was performed. The ultimate failure load, elongation at failure, and mode of failure were recorded, and the resulting load-elongation curve was documented. Results: The drill tunnel through the cortical surface (anterior to posterior) was found to be significantly stronger than the drill tunnel through the cancellous surface (medial to lateral). There were no significant differences found when comparing the strength of the suture augmentation through the tendon and the drill tunnel alone (P = .13 among cancellous groups, P = .09 among cortical groups). The cortical drill tunnel with suture augmentation through the tendon showed significantly greater elongation values (13.7 ± 3.2) at failure when compared with either the cancellous or cortical drill tunnel only test groups (P = .0003 compared with cancellous alone, P = .009 when compared with cortical alone). Conclusions: The BPTB suture configuration with an anterior to posterior-directed suture tunnel without a suture through tendon augmentation provides the optimal strength and stiffness while minimizing graft elongation after fixation in a biomechanical model. This configuration is best for preventing suture pull through and failure when passing sutures through the BPTB plug. Clinical Relevance: This study biomechanically evaluates the optimal suture configuration in the proximal bone plug for suspensory fixation in the setting of BPTB grafts.

Anatomic safe zones for arthroscopic snapping scapula surgery: quantitative anatomy of the superomedial scapula and associated neurovascular structures and the effects of arm positioning on safety.

BACKGROUND: Neurovascular anatomy has not been previously quantified for the arthroscopic snapping scapula approach with the patient in the most frequent patient position ("chicken-wing" position). The purposes of this study were (1) to determine anatomic relationships of the superomedial scapula and neurovascular structures at risk during arthroscopic surgical treatment of snapping scapula syndrome (SSS), (2) to compare these measurements between the arm in the neutral position and the arm in the chicken-wing position, and (3) to establish safe zones for arthroscopic treatment of SSS. METHODS: Eight fresh-frozen cadaveric hemi-torsos (mean age, 55.8 years; range, 52-66 years) were dissected to ascertain relevant anatomic structure locations including the (1) spinal accessory nerve, (2) dorsal scapular nerve, and (3) suprascapular nerve. A coordinate measuring device was used to collect data on the relationships of anatomic landmarks and at-risk structures during the surgical approach. RESULTS: The dorsal scapular nerve was a mean of 24.4 mm medial to the superomedial scapula in the neutral position and 33.1 mm medial in the chicken-wing position (P < .001); the dorsal scapular nerve was 21.7 mm medial to the medial border of the scapular spine in the neutral position and 35.5 mm medial in the chicken-wing position (P < .001). The mean distance from the superomedial angle to the spinal accessory nerve intersection at the superior scapular border was 16.5 mm in the neutral position and 15.0 mm in the chicken-wing position (P = .031). The average distance from the superomedial angle to the closest point of the spinal accessory nerve was 11.6 mm and 10.4 mm in the neutral position and chicken-wing position, respectively (P = .039). CONCLUSION: Neurologic structures around the scapula vary significantly between the neutral arm position and the chicken-wing position commonly used in the arthroscopic treatment of SSS. The chicken-wing position improves safe distances for the dorsal scapular nerve during medial-portal placement and should be considered as a primary position for arthroscopic management of SSS.

Accuracy and Reliability of Software Navigation for Acetabular Component Placement in THA: An In Vitro Validation Study.

Background and Objectives: Intraoperative fluoroscopy can be used to increase the accuracy of the acetabular component positioning during total hip arthroplasty. However, given the three-dimensional nature of cup positioning, it can be difficult to accurately assess inclination and anteversion angles based on two-dimensional imaging. The purpose of this study is to validate a novel method for calculating the 3D orientation of the acetabular cup from 2D fluoroscopic imaging. Materials and Methods: An acetabular cup was implanted into a radio-opaque pelvis model in nine positions sequentially, and the inclination and anteversion angles were collected in each position using two methods: (1) a coordinate measurement machine (CMM) was used to establish a digitalized anatomical coordinate frame based on pelvic landmarks of the cadaveric specimen, and the 3D position of the cup was then expressed with respect to the anatomical planes; (2) AP radiographic images were collected, and a mathematical formula was utilized to calculate the 3D inclination and anteversion based on the 2D images. The results of each method were compared, and interrater and intrarater reliably of the 2D method were calculated. Results: Interrater reliability was excellent, with an interclass correlation coefficient (ICC) of 0.988 (95% CI 0.975-0.994) for anteversion and 0.997 (95% CI 0.991-0.999) for inclination, as was intrarater reliability, with an ICC of 0.995 (95% CI 0.985-0.998) for anteversion and 0.998 (95% CI 0.994-0.999) for inclination. Intermethod accuracy was excellent with an ICC of 0.986 (95% CI: 0.972-0.993) for anteversion and 0.993 (95% CI: 0.989-0.995) for inclination. The Bland-Altman limit of agreement, which represents the error between the 2D and 3D methods, was found to range between 2 to 5 degrees. Conclusions: This data validates the proposed methodology to calculate 3D anteversion and inclination angles based on 2D fluoroscopic images to within five degrees. This method can be utilized to improve acetabular component placing intraoperatively and to check component placement postoperatively.

Subscapularis repair in reverse total shoulder arthroplasty: a systematic review and descriptive synthesis of cadaveric biomechanical strength outcomes.

Hypothesis/Background: There is no consensus on whether to repair the subscapularis in the setting of reverse total shoulder arthroplasty (rTSA). There have been an assortment of studies showing mixed results regarding shoulder stability and postoperative strength outcomes when looking at subscapularis repair in rTSA. The purpose of this systematic review was to investigate differences in biomechanical strength outcomes of cadaveric subscapularis repair vs. no repair in rTSA.Increased force will be required to move the shoulder through normal range of motion (ROM) in cadaveric rTSA shoulders with the subscapularis repaired when compared with no subscapularis repair. Methods: A comprehensive literature review was conducted in accordance with the 2009 Preferred Reporting Items for Systematic Review and Meta-Analysis statement. The databases used to search the keywords used for the concepts of subscapularis, reverse total shoulder arthroplasty, and muscle strength were PubMed (includes MEDLINE), Embase, Web of Science, Cochrane Reviews and Trials, and Scopus. Original, English-language cadaveric studies evaluating rTSA and subscapularis management were included, with subscapularis repair surgical techniques and strength outcomes being evaluated for each article meeting inclusion criteria. Results: The search yielded 4113 articles that were screened for inclusion criteria by 4 authors. Two articles met inclusion criteria and were subsequently included in the final full-text review. A total of 11 shoulders were represented between these 2 studies. Heterogeneity of the data across the 2 studies did not allow for meta-analysis. Hansen et al found that repair of the subscapularis with rTSA significantly increased the mean joint reaction force and the force required by the posterior deltoid, total deltoid, infraspinatus, teres minor, total posterior rotator cuff, and pectoralis major muscles. Giles et al found that rotator cuff repair and glenosphere lateralization both increased total joint load. Conclusion: The present review of biomechanical literature shows that repair of the subscapularis in the setting of rTSA can effectively restore shoulder strength by increasing joint reactive forces and ROM force requirements of other rotator cuff muscles and of the deltoid muscle. Available biomechanical evidence is limited, and further biomechanical studies evaluating the strength of various subscapularis repair techniques are needed to evaluate the effects of these techniques on joint reactive forces and muscle forces required for ROM.