Editorial Commentary: Noninferiority of Anterior Cruciate Ligament Repair With Dynamic Intraligamentary Stabilization at Short- to Mid-Term Follow-Up Does Not Justify Superseding Anterior Cruciate Ligament Reconstruction as the "Gold Standard" for Anterior Cruciate Ligament Surgery.

With advances in surgical technology, including the introduction of some kind of mechanical augmentation, there has been a resurgence of interest in primary repair of the anterior cruciate ligament (ACL). If successful, ACL repairs may provide several advantages over reconstruction resulting from the preservation of the native anatomy and proprioception. Recently, augmentation of ACL repair using dynamic intraligamentary stabilization (DIS) has been proposed, to create an optimal biomechanical environment for healing. In the DIS technique, an additional nonresorbable cord is placed along the ACL and attached to a dynamic spring fixed in the proximal tibia, keeping the tibia in a posterior drawer position at every degree of flexion. The analyzed randomized controlled trials comparing ACL repair with DIS to ACL reconstruction found overall similar failure and revision rates, whereas the few observed statistically significant differences in functional scores or knee stability favoring either of the techniques were clearly not clinically relevant. Of course, repair of a torn ACL should be limited to a specific subset of patients presenting with an acute femoral avulsion tear with minimal retraction and good tissue quality. However, the present short- to mid-term results do not justify ACL reconstruction to be superseded by ACL repair with DIS as the "gold standard" for surgical treatment of ACL tears in the future, even in this subset of patients.

Noninvasive and Reliable Quantification of Anteromedial Rotatory Knee Laxity: A Pilot Study on Healthy Individuals.

BACKGROUND: Anteromedial rotatory instability (AMRI) of the knee is a complex and severe condition caused by injury to the anterior cruciate ligament and/or the medial collateral ligament. Clinical studies dealing with AMRI are rare, and objective measurements are nonexistent. PURPOSE/HYPOTHESIS: The objectives of this study were, first, to quantify anteromedial rotatory knee laxity in healthy individuals using a noninvasive image analysis software and, second, to assess intra- and interrater reliability and equivalence in measuring anteromedial knee translation (AMT). It was hypothesized that AMT could be reliably quantified using a noninvasive image analysis software. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This prospective proof-of-concept study included healthy individuals aged 16 to 40 years with no history of knee injury or surgery. Three adhesive surface markers were placed on predefined landmarks on the medial side of the knee. Three independent investigators examined anteromedial rotatory knee laxity with an anterior drawer test in different tibial rotations (neutral tibial rotation, 15° of external tibial rotation, and 15° of internal tibial rotation). The entire examination of each knee was recorded, and AMT including the side-to-side difference (SSD) was assessed using a freely available and validated image analysis software (PIVOT iPad application). Group comparisons were performed using a 1-way analysis of variance with Bonferroni-adjusted post hoc analysis. Intraclass correlation coefficients (ICCs) were calculated to assess inter- and intrarater reliability of AMT measurements. Equivalence of measurements was evaluated using the 2 one-sided t-test procedure. RESULTS: Anteromedial rotatory knee laxity was assessed in 30 knees of 15 participants (53% male) with a mean age of 26.2 ± 3.5 years. In all 3 raters, the highest AMT was observed in neutral tibial rotation (range of means, 2.2-3.0 mm), followed by external tibial rotation (range of means, 2.0-2.4 mm) and internal tibial rotation (range of means, 1.8-2.2 mm; P < .05). Intrarater reliability of AMT (ICC, 0.88-0.96) and SSD (ICC, 0.61-0.96) measurements was good to excellent and moderate to excellent, respectively. However, interrater reliability was poor to moderate for AMT (ICC, 0.44-0.73) and SSD (ICC, 0.12-0.69) measurements. Statistically significant equivalence of AMT and SSD measurements was observed between and within raters for almost all testing conditions. CONCLUSION: Anteromedial rotatory knee laxity could be quantified using a noninvasive image analysis software, with the highest AMT observed during neutral tibial rotation in uninjured individuals. Reliability and equivalence of measurements were good to excellent within raters and moderate between raters.

Tibiofemoral Subluxation on Radiograph as a Predictor of Location and Size of Osteochondritis Dissecans Lesions of the Knee.

Background: Lower limb malalignment has been associated with osteochondritis dissecans (OCD). However, the location of the OCD lesion often is not concordant with the mechanical leg axis. Other potentially modifiable alignment parameters may influence the propensity for impingement of the femoral condyles. Purpose: To assess differences in lower limb alignment (LLA) and relative tibiofemoral position between patients with medial (MFC-OCD) or lateral OCD (LFC-OCD) of the femoral condyle. Study Design: Cohort study; Level of evidence, 3. Methods: Patients ≤30 years old who were diagnosed with unicondylar OCD between January 2010 and January 2020 were eligible for this study. Included were 55 patients (age, 20.8 ± 4.5 years)-46 with MFC-OCD and 9 with LFC-OCD. Preoperative standing long-leg radiographs were studied to obtain primary outcomes-including LLA and mechanical alignment analyses-and secondary outcomes-including knee joint obliquity angle; rotation angle; medial, central (c-subluxation), and lateral subluxation (L-subluxation) of the tibia relative to the femur in the coronal plane; and tibiofemoral joint line center distance (TFJCD). Results: With regard to primary outcomes, LLA was significantly different between MFC-OCD (1.7°± 3.1° varus) and LFC-OCD (2.7 ± 3.1° valgus) (P < .001), and 78% (36/46) of patients with MFC-OCD had varus alignment, whereas 78% (7/9) of patients with LFC-OCD had valgus alignment (P < 0.002). With regard to secondary outcomes, patients with MFC-OCD had a more medial tibial position in relation to the femur, with a significantly smaller rotation angle (5.6°± 2.4° vs 9.6°± 3.6°; P < .001), a smaller C-subluxation (7.2 ± 6.6 vs 14.9 ± 8.8 mm; P < .01), a smaller L-subluxation (2.3 ± 2.6 vs 4.4 ± 2.7 mm; P < .05), and reduced TFJCD (3.5 ± 1.7 vs 6.6 ± 1.8 mm; P < .001) compared with the LFC-OCD group. For patients with MFC-OCD, the size of the OCD was significantly correlated with C-subluxation (r = 0.412; P = .006). Conclusion: LLA was significantly different according to OCD location. In patients with MFC-OCD, the tibia was subluxated medially, resulting in a change of joint geometry by approximation of the medial tibial eminence toward the medial femoral condyle, potentially causing excessive pressure overload and microtrauma of the cartilage. Interestingly, the extent of subluxation was correlated with OCD size.

Long-Term Functional Outcomes and Athletic Ability in Shoulder Sports After Anatomic Coracoclavicular Ligament Reconstruction for Chronic Type 3 and 5 Acromioclavicular Joint Injuries.

Background: Promising short- and midterm outcomes have been seen after anatomic coracoclavicular ligament reconstruction (ACCR) for chronic acromioclavicular joint (ACJ) injuries. Purpose/Hypothesis: To evaluate long-term outcomes and shoulder-related athletic ability in patients after ACCR for chronic type 3 and 5 ACJ injuries. It was hypothesized that these patients would maintain significant functional improvement and sufficient shoulder-sport ability at a long-term follow-up. Study Design: Case series; Level of evidence, 4. Methods: Included were 19 patients (mean age, 45.9 ± 11.2 years) who underwent ACCR for type 3 or 5 ACJ injuries between January 2003 and August 2014. Functional outcome measures included the American Shoulder and Elbow Surgeons (ASES), Rowe, Constant-Murley, Simple Shoulder Test (SST), and Single Assessment Numeric Evaluation (SANE) scores as well as the visual analog scale (VAS) for pain, which were collected preoperatively and at the final follow-up. Postoperative shoulder-dependent athletic ability was assessed using the Athletic Shoulder Outcome Scoring System (ASOSS). Shoulder activity level was evaluated using the Shoulder Activity Scale (SAS), while the Subjective Patient Outcome for Return to Sports (SPORTS) score was collected to assess the patients' ability to return to their preinjury sporting activity. Results: The mean follow-up time was 10.1 ± 3.8 years (range, 6.1-18.8 years). Patients achieved significant pre- to postoperative improvements on the ASES (from 54.2 ± 22.6 to 83.5 ± 23.1), Rowe (from 66.6 ± 18.1 to 85.3 ± 19), Constant-Murley (from 64.6 ± 20.9 to 80.2 ± 22.7), SST (from 7.2 ± 3.4 to 10.5 ± 2.7), SANE (from 30.1 ± 23.2 to 83.6 ± 26.3), and VAS pain scores (from 4.7 ± 2.7 to 1.8 ± 2.8) (P < .001 for all), with no significant differences between type 3 and 5 injuries. At the final follow-up, patients achieved an ASOSS of 80.6 ± 32, SAS level of 11.6 ± 5.1, and SPORTS score of 7.3 ± 4.1, with no significant differences between type 3 and 5 injuries. Four patients (21.1%) had postoperative complications. Conclusion: Patients undergoing ACCR using free tendon allografts for chronic type 3 and 5 ACJ injuries maintained significant improvements in functional outcomes at the long-term follow-up and achieved favorable postoperative shoulder-sport ability, activity, and return to preinjury sports participation.

Anterior Latissimus Dorsi Transfer for Irreparable Subscapularis Tears Improves Shoulder Kinematics in a Dynamic Biomechanical Cadaveric Shoulder Model.

BACKGROUND: In young patients with irreparable subscapularis deficiency (SSC-D) and absence of severe osteoarthritis, anterior latissimus dorsi transfer (aLDT) has been proposed as a treatment option to restore the anteroposterior muscular force couple to regain sufficient shoulder function. However, evidence regarding the biomechanical effect of an aLDT on glenohumeral kinematics remains sparse. PURPOSE/HYPOTHESIS: The purpose of this study was to investigate the effects of an aLDT on range of glenohumeral abduction motion, superior migration of the humeral head (SM), and cumulative deltoid force (cDF) in a simulated SSC-D model using a dynamic shoulder model. It was hypothesized that an aLDT would restore native shoulder kinematics by reestablishing the insufficient anteroposterior force couple. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen cadaveric shoulders were tested using a validated shoulder simulator. Glenohumeral abduction angle (gAA), SM, and cDF were compared across 3 conditions: (1) native, (2) SSC-D, and (3) aLDT. gAA and SM were measured using 3-dimensional motion tracking, while cDF was recorded in real time during dynamic abduction motion by load cells connected to actuators. RESULTS: The SSC-D significantly decreased gAA (Δ-9.8°; 95% CI, -14.1° to -5.5°; P < .001) and showed a significant increase in SM (Δ2.0 mm; 95% CI, 0.9 to 3.1 mm; P = .003), while cDF was similar (Δ7.8 N; 95% CI, -9.2 to 24.7 N; P = .586) when compared with the native state. Performing an aLDT resulted in a significantly increased gAA (Δ3.8°; 95% CI, 1.8° to 5.7°; P < .001), while cDF (Δ-36.1 N; 95% CI, -48.7 to -23.7 N; P < .001) was significantly reduced compared with the SSC-D. For the aLDT, no anterior subluxation was observed. However, the aLDT was not able to restore native gAA (Δ-6.1°; 95% CI, -8.9° to -3.2°; P < .001). CONCLUSION: In this cadaveric study, performing an aLDT for an irreparable subscapularis insufficiency restored the anteroposterior force couple and prevented superior and anterior humeral head migration, thus improving glenohumeral kinematics. Furthermore, compensatory deltoid forces were reduced by performing an aLDT. CLINICAL RELEVANCE: Given the favorable effect of the aLDT on shoulder kinematics in this dynamic shoulder model, performing an aLDT may be considered as a treatment option in patients with irreparable SSC-D.

The effect of augmenting suture material with magnesium and platelet-rich plasma on the in vitro adhesion and proliferation potential of subacromial bursa-derived progenitor cells.

Background: Connective tissue subacromial bursa-derived progenitor cells (SBDCs) have been suggested as a potent biologic augment to promote healing of the repaired rotator cuff tendon. Maximizing the amount of retained progenitor cells at the tendon repair site is essential for ensuring an optimal healing environment, warranting a search for proadhesive and proliferative adjuvants. The purpose was to evaluate the effect of magnesium (Mg), platelet-rich plasma (PRP), and a combination of both adjuvants on the in vitro cellular adhesion and proliferation potential of SBDCs on suture material commonly used in rotator cuff surgery. Methods: SBDCs were isolated from subacromial bursa samples harvested during rotator cuff repair and cultured in growth media. Commercially available collagen-coated nonabsorbable flat-braided suture was cut into 1-inch pieces, placed into 48-well culture dishes, and sterilized under ultraviolet light. Either a one-time dose of 5 mM sterile Mg, 0.2 mL of PRP, or a combination of both adjuvants was added, while a group without treatment served as a negative control. Cellular proliferation and adhesion assays on suture material were performed for each treatment condition. Results: Augmenting the suture with Mg resulted in a significantly increased cellular adhesion (total number of attached cells) of SBDCs compared to PRP alone (31,527 ± 19,884 vs. 13,619 ± 8808; P < .001), no treatment (31,527 ± 19,884 vs. 21,643 ± 8194; P = .016), and combination of both adjuvants (31,527 ± 19,884 vs. 17,121 ± 11,935; P < .001). Further, augmentation with Mg achieved a significant increase in cellular proliferation (absorbance) of SBDCs on suture material when compared to the PRP (0.516 ± 0.207 vs. 0.424 ± 0.131; P = .001) and no treatment (0.516 ± 0.207 vs. 0.383 ± 0.094; P < .001) group. The combination of Mg and PRP showed a significantly higher proliferation potential compared to PRP alone (0.512 ± 0.194 vs. 0.424 ± 0.131; P = .001) and no treatment (0.512 ± 0.194 vs. 0.383 ± 0.094; P < .001). There were no significant differences in the remaining intergroup comparisons (P > .05, respectively). Conclusion: Augmenting suture material with Mg resulted in a significantly increased cellular adhesion of SBDCs compared to untreated suture material, as well as augmentation with PRP alone or a combination of both adjuvants. Further, Mg with or without PRP augmentation achieved a significant increase in the cellular proliferation of SBDCs on suture material compared to untreated sutures and augmentation with PRP alone. Application of Mg may be a clinically feasible approach to optimizing the use of SBDCs as a biological augment in rotator cuff repair, while combined augmentation with PRP may harness the full potential for optimized tissue recovery due to the high concentration of PRP-derived growth factors.

The importance of a structured failure analysis in revision acromioclavicular joint surgery: A multi-rater agreement on the causes of stabilization failure from the ISAKOS shoulder committee.

BACKGROUND: Acromioclavicular joint (ACJ) stabilizations are associated with a high overall failure rate with 9.5% of these patients requiring subsequent revision surgery. Consequently, understanding the specific cause of primary ACJ stabilization failure is paramount to improving surgical decision-making in this challenging patient cohort. PURPOSE: To (1) identify risk factors and mechanisms for failure following primary arthroscopically-assisted ACJ stabilization to highlight the importance of conducting a detailed failure analysis and to (2) establish revision strategies based on real-life cases of primary failed ACJ stabilization. STUDY DESIGN: Level of evidence IV. METHODS: A survey was shared internationally among members of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) shoulder committee. The survey contained failure analysis of 11 real-life cases of failed primary arthroscopically-assisted ACJ stabilization. For each case, a thorough patient history, standardized radiographs, and CT scans were provided. Participants were asked to give their opinion on bone tunnel placement, cause of failure (biological, technical, traumatic, or combined), the stabilization technique used, as well as give a recommendation for revision. RESULTS: Seventeen members of the ISAKOS shoulder committee completed the survey. Biological failure was considered the most common cause of failure (47.1%), followed by technical (35.3%) and traumatic (17.6%) failure. The majority deemed two modifiable factors (i.e., patient's profession and sport) as well as non-modifiable factors (i.e., patient's age and time from trauma to initial surgery) to be risk factors for failure. In 10 of 11 cases, the correct fixation device was used in the primary setting (90.9%; 52.8-82.4% agreement); however, in eight of those cases, the technique was not performed correctly (80.0%; 58.8-100% agreement). In 8 of all 11 cases, the majority recommended an arthroscopically assisted technique with graft augmentation for revision (52.9-58.8% agreement). CONCLUSION: Biological failure and technical failure are the most common reason for failure in primary ACJ stabilization followed by traumatic failure. Besides, biological failure can be triggered by technical errors such as clavicular or coracoidal tunnel misplacement. Consequently, a detailed failure analysis including preoperative CT should be conducted on the causes of primary ACJ failure, and, if possible, an arthroscopically-assisted technique with graft augmentation should be prioritized in revision ACJ surgery. CLINICAL RELEVANCE: ACJ stabilizations are associated with a high overall failure rate - potentially due to biological and technical properties. When encountering failed arthroscopically-assisted ACJ stabilization, a detailed failure analysis should be conducted on the causes of primary ACJ failure. Furthermore, an arthroscopically-assisted revision stabilization is feasible in most cases.

Contact Mechanics of Elliptical and Spherical Head Implants during Axial Rotation in Anatomic Total Shoulder Arthroplasty: A Biomechanical Comparison.

BACKGROUND: Elliptical humeral head implants have been proposed to result in more anatomic kinematics following total shoulder arthroplasty (aTSA). The purpose of this study was to compare glenohumeral contact mechanics during axial rotation using spherical and elliptical humeral head implants in the setting of aTSA. METHODS: Seven fresh-frozen cadaveric shoulders were utilized for biomechanical testing in neutral (NR), internal (IR), and external (ER) rotation at various levels of abduction (0°, 15°, 30°, 45°, 60°) with lines of pull along each of the rotator cuff muscles. Each specimen underwent the following three conditions: (1) native, and TSA using (2) an elliptical and (3) spherical humeral head implant. Glenohumeral contact mechanics, including contact pressure (CP; kPa), peak contact pressure (PCP; kPa), and contact area (CA; mm2), were measured in neutral rotation as well as external and internal rotation using a pressure mapping sensor. RESULTS: Elliptical head implants showed a significantly lower PCP in ER compared to spherical implants at 0° (Δ-712.0 kPa; p = 0.034), 15° (Δ-894.9 kPa; p = 0.004), 30° (Δ-897.7 kPa; p = 0.004), and 45° (Δ-796.9 kPa; p = 0.010) of abduction, while no significant difference was observed in ER at 60° of abduction or at all angles in NR and IR. Both implant designs had similar CA in NR, ER, and IR at all tested angles of abduction (p > 0.05, respectively). CONCLUSIONS: In the setting of aTSA, elliptical heads showed significantly lower PCP during ER at 0° to 45° of abduction, when compared to spherical head implants. However, in NR and IR, PCP was similar between implant designs. Both designs showed similar CA during NR, ER, and IR at all abduction angles. LEVEL OF EVIDENCE: basic science; controlled laboratory study.

Physiological Tensioning During Lower Trapezius Transfer for Irreparable Posterosuperior Rotator Cuff Tears May Be Important for Improvement in Shoulder Kinematics.

BACKGROUND: Lower trapezius transfer (LTT) has been proposed for restoring the anteroposterior muscular force couple in the setting of an irreparable posterosuperior rotator cuff tear (PSRCT). Adequate graft tensioning during surgery may be a factor critical for sufficient restoration of shoulder kinematics and functional improvement. PURPOSE/HYPOTHESIS: The purpose was to evaluate the effect of tensioning during LTT on glenohumeral kinematics using a dynamic shoulder model. It was hypothesized that LTT, while maintaining physiological tension on the lower trapezius muscle, would improve glenohumeral kinematics more effectively than undertensioned or overtensioned LTT. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 10 fresh-frozen cadaveric shoulders were tested using a validated shoulder simulator. Glenohumeral abduction angle, superior migration of the humeral head, and cumulative deltoid force were compared across 5 conditions: (1) native, (2) irreparable PSRCT, (3) LTT with a 12-N load (undertensioned), (4) LTT with a 24-N load (physiologically tensioned according to the cross-sectional area ratio of the lower trapezius muscle), and (5) LTT with a 36-N load (overtensioned). Glenohumeral abduction angle and superior migration of the humeral head were measured using 3-dimensional motion tracking. Cumulative deltoid force was recorded in real time throughout dynamic abduction motion by load cells connected to actuators. RESULTS: Physiologically tensioned (Δ13.1°), undertensioned (Δ7.3°), and overtensioned (Δ9.9°) LTT each significantly increased the glenohumeral abduction angle compared with the irreparable PSRCT (P < .001 for all). Physiologically tensioned LTT achieved a significantly greater glenohumeral abduction angle than undertensioned LTT (Δ5.9°; P < .001) or overtensioned LTT (Δ3.2°; P = .038). Superior migration of the humeral head was significantly decreased with LTT compared with the PSRCT, regardless of tensioning. Physiologically tensioned LTT resulted in significantly less superior migration of the humeral head compared with undertensioned LTT (Δ5.3 mm; P = .004). A significant decrease in cumulative deltoid force was only observed with physiologically tensioned LTT compared with the PSRCT (Δ-19.2 N; P = .044). However, compared with the native state, LTT did not completely restore glenohumeral kinematics, regardless of tensioning. CONCLUSION: LTT was most effective in improving glenohumeral kinematics after an irreparable PSRCT when maintaining physiological tension on the lower trapezius muscle at time zero. However, LTT did not completely restore native glenohumeral kinematics, regardless of tensioning. CLINICAL RELEVANCE: Tensioning during LTT for an irreparable PSRCT may be important to sufficiently improve glenohumeral kinematics and may be an intraoperatively modifiable key variable to ensure postoperative functional success.

Dual Bracing for Ulnar Collateral Ligament Injuries Restores Native Valgus Laxity and Native Medial Joint Gapping of the Elbow.

Background: Despite growing evidence on the role of the posterior ulnar collateral ligament (pUCL) in elbow stability, current ligament bracing techniques are mainly focused on the anterior ulnar collateral ligament (aUCL). A dual-bracing technique combines the repair of the pUCL and aUCL with a suture augmentation of both bundles. Purpose: To biomechanically assess a dual-bracing approach addressing aUCL and pUCL for humeral-sided complete UCL lesions to restore medial elbow laxity without overconstraining. Study Design: Controlled laboratory study. Methods: A total of 21 unpaired human elbows (11 right, 10 left; 57.19 ± 11.7 years) were randomized into 3 groups to compare dual bracing with aUCL suture augmentation and aUCL graft reconstruction. Laxity testing was performed with 25 N applied 12 cm distal to the elbow joint for 30 seconds at randomized flexion angles (0°, 30°, 60°, 90°, and 120°) for the native condition and then for each surgical technique. A calibrated motion capture system was used for assessment, allowing the 3-dimensional displacement during the complete valgus stress cycle between the optical trackers to be quantified as joint gap and laxity. The repaired constructs were then cyclically tested through a materials testing machine starting with 20 N for 200 cycles at a rate of 0.5 Hz. The load was increased stepwise by 10 N for 200 cycles until displacement reached 5.0 mm or complete failure occurred. Results: Dual bracing and aUCL bracing resulted in significantly (P = .045) less joint gapping at 120° of flexion compared with aUCL reconstruction. No significant differences in valgus laxity were found among the surgical techniques. Within each technique, there were no significant differences between the native and the postoperative state in valgus laxity and joint gapping. No significant differences between the techniques were observed in cycles to failure and failure load. Conclusion: Dual bracing restored native valgus joint laxity and medial joint gapping without overconstraining and provided similar primary stability regarding failure outcomes as established techniques. Furthermore, it was able to restore joint gapping in 120° of flexion significantly better than aUCL reconstruction. Clinical Relevance: This study provides biomechanical data on the dual-bracing approach that may help surgeons to consider this new method of addressing acute humeral UCL lesions.

Superior Capsular Reconstruction Partially Restores Native Glenohumeral Joint Loads in a Dynamic Biomechanical Shoulder Model.

PURPOSE: To evaluate the effect of an irreparable posterosuperior rotator cuff tear (PSRCT) on glenohumeral joint loads and to quantify improvement after superior capsular reconstruction (SCR) using an acellular dermal allograft. METHODS: Ten fresh-frozen cadaveric shoulders were tested using a validated dynamic shoulder simulator. A pressure mapping sensor was placed between the humeral head and glenoid surface. Each specimen underwent the following conditions: (1) native, (2) irreparable PSRCT, and (3) SCR using a 3-mm-thick acellular dermal allograft. Glenohumeral abduction angle (gAA) and superior humeral head migration (SM) were measured using 3-dimensional motion-tracking software. Cumulative deltoid force (cDF) and glenohumeral contact mechanics, including glenohumeral contact area and glenohumeral contact pressure (gCP), were assessed at rest, 15°, 30°, 45°, and maximum angle of glenohumeral abduction. RESULTS: The PSRCT resulted in a significant decrease of gAA along with an increase in SM, cDF, and gCP (P < .001, respectively). SCR did not restore native gAA (P < .001); however, SM was significantly reduced (P < .001). Further, SCR significantly reduced deltoid forces at 30° (P = .007) and 45° of abduction (P = .007) when compared with the PSRCT. SCR did not restore native cDF at 30° (P = .015), 45° (P < .001), and maximum angle (P < .001) of glenohumeral abduction. Compared with the PSRCT, SCR resulted in a significant decrease of gCP at 15° (P = .008), 30° (P = .002), and 45° (P = .006). However, SCR did not completely restore native gCP at 45° (P = .038) and maximum abduction angle (P = .014). CONCLUSIONS: In this dynamic shoulder model, SCR only partially restored native glenohumeral joint loads. However, SCR significantly decreased glenohumeral contact pressure, cumulative deltoid forces, and superior migration, while increasing abduction motion, when compared with the posterosuperior rotator cuff tear. CLINICAL RELEVANCE: These observations raise concerns regarding the true joint-preserving potential of SCR for an irreparable posterosuperior rotator cuff tear, along with its ability to delay progression of cuff tear arthropathy and eventual conversion to reverse shoulder arthroplasty.

Elliptical and spherical heads show similar obligate glenohumeral translation during axial rotation in total shoulder arthroplasty.

BACKGROUND: Elliptical shape humeral head prostheses have been recently proposed to reflect a more anatomic shoulder replacement. However, its effect on obligate glenohumeral translation during axial rotation compared to a standard spherical head is still not well understood. The purpose of the study was to compare obligate humeral translation during axial rotation using spherical and elliptical shaped humeral head prostheses. It was hypothesized that the spherical head design would show significantly more obligate translation when compared to the elliptical design. METHODS: Six fresh-frozen cadaveric shoulders were utilized for biomechanical testing of internal (IR) and external (ER) rotation at various levels of abduction (0°, 30°, 45°, 60°) with lines of pull along each of the rotator cuff muscles. Each specimen underwent the following three conditions: (1) native; total shoulder arthroplasty (TSA) using (2) an elliptical and (3) spherical humeral head implant. Obligate translation during IR and ER was quantified using a 3-dimensional digitizer. The radius of curvature of the superoinferior and anteroposterior dimensions of the implants was calculated across each condition. RESULTS: Posterior and inferior translation as well as compound motion of spherical and elliptical heads during ER was similar at all abduction angles (P > 0.05, respectively). Compared to the native humeral head, both implants demonstrated significantly decreased posterior translation at 45° (elliptical: P = 0.003; spherical: P = 0.004) and 60° of abduction (elliptical: P < 0.001; spherical: P < 0.001). During internal rotation at 0° abduction, the spherical head showed significantly more compound motion (P = 0.042) compared to the elliptical head. The spherical implant also demonstrated increased anterior translation and compound motion during internal rotation at 60° abduction (P < 0.001) compared to the resting state. This difference was not significant for the native or elliptical head design at this angle (P > 0.05). CONCLUSION: In the setting of TSA, elliptical and spherical head implants showed similar obligate translation and overall compound motion during axial rotation. A gained understanding of the consequences of implant head shape in TSA may guide future surgical implant choice for better recreation of native shoulder kinematics and potentially improved patient outcomes. LEVEL OF EVIDENCE: Controlled Laboratory Study.

Favorable rates of return to activity and work following lateral closing wedge distal femoral osteotomy for femoral-based symptomatic varus malalignment: an analysis at a mean 6-year follow-up.

PURPOSE: To evaluate return to sport (RTS), work (RTW) and clinical outcomes following lateral closing wedge distal femoral osteotomy (LCW-DFO) for symptomatic femoral varus malalignment. METHODS: Consecutive patients who underwent LCW-DFO for symptomatic varus malalignment between 12/2007 and 03/2018 were included. The International Knee Documentation Committee (IKDC) Score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, Tegner Activity Scale, and visual analogue scale (VAS) for pain were collected preoperatively and at a minimum of 24 months postoperatively. RTS and RTW were assessed by questionnaire. RESULTS: Thirty-two patients (mean age: 45.9 ± 12.3 years), who underwent LCW-DFO for femoral-based varus malalignment (6.4 ± 3.0°), were included at a mean follow-up of 72.7 ± 39.1 months. The patient collective significantly improved in IKDC (51.8 ± 12.3 to 61.8 ± 21.5, p = 0.010; 95% CI = 3-21), WOMAC (26.7 ± 17.6 to 12.5 ± 13.5; p < 0.001; 95% CI = 21-6) and Lysholm (46.5 ± 19.4 to 67.9 ± 22.8 points (p < 0.01; 95% CI = 9-31)) scores at final follow-up. The VAS for pain reduced significantly postoperatively (4.8 ± 2.3 points to 2.6 ± 2.3 points (p = 0.002; 95% CI = 0-3)). Following LCW-DFO, 96% of patients returned to sports at a mean of 5.3 ± 2.9 months. Yet, a shift to lower impact sports compared to one year preoperatively was observed, with patients participating in a significantly lower number of high-impact disciplines (p = 0.024) and fewer hours in high-impact sports (p = 0.034). Twenty-three out of 24 patients returned to work at a mean 11.4 ± 10.9 weeks, with 18 patients reporting a similar or superior working ability. CONCLUSION: Undergoing isolated LCW-DFO for symptomatic femoral-based varus malalignment enabled the vast majority of patients to RTS and RTW along with a significant functional improvement at mid-term follow-up. However, patients' expectations have to be adequately managed regarding a limited probability to return to high-impact sports and work after surgery. LEVEL OF EVIDENCE: Retrospective case series; Level IV.

Clinical Effect of Isolated Lateral Closing Wedge Distal Femoral Osteotomy Compared to Medial Opening Wedge High Tibial Osteotomy for the Correction of Varus Malalignment: A Propensity Score-Matched Analysis.

BACKGROUND: Recent evidence questions the role of medial opening wedge high tibial osteotomy (mowHTO) in the correction of femoral-based varus malalignment because of the potential creation of an oblique knee joint line. However, the clinical effectiveness of alternatively performing an isolated lateral closing wedge distal femoral osteotomy (lcwDFO), in which the mechanical unloading effect in knee flexion may be limited, is yet to be confirmed. PURPOSE/HYPOTHESIS: The purpose of this article was to compare clinical outcomes between patients undergoing varus correction via isolated lcwDFO or mowHTO, performed according to the location of the deformity, in a cohort matched for confounding variables. It was hypothesized that results from undergoing isolated lcwDFO for symptomatic varus malalignment would not significantly differ from the results after mowHTO. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Consecutive patients who underwent isolated mowHTO or lcwDFO according to a tibial- or femoral-based symptomatic varus deformity between January 2010 and October 2019 were enrolled. Confounding factors, including age at surgery, sex, body mass index, preoperative femorotibial axis, and postoperative follow-up, were matched using propensity score matching. The International Knee Documentation Committee (IKDC) Subjective Knee Form, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, Tegner Activity Scale, and visual analog scale (VAS) for pain were collected preoperatively and at a minimum of 24 months postoperatively. RESULTS: Of 535 knees assessed for eligibility, 50 knees (n = 50 patients, n = 25 per group) were selected by propensity score matching. Compared with preoperatively, both the mowHTO group (IKDC, 55.1 ± 16.5 vs 71.3 ± 14.7, P = .002; WOMAC, 22.0 ± 18.0 vs 9.6 ± 10.8, P < .001; Lysholm, 55.2 ± 23.1 vs 80.7 ± 16, P < .001; VAS, 4.1 ± 2.4 vs 1.6 ± 1.8, P < .001) and the lcwDFO group (IKDC, 49.4 ± 14.6 vs 66 ± 20.1, P = .003; WOMAC, 25.2 ± 17.0 vs 12.9 ± 17.6, P = .003; Lysholm, 46.5 ± 15.6 vs 65.4 ± 28.7, P = .011; VAS, 4.5 ± 2.2 vs 2.6 ± 2.5, P = .001) had significantly improved at follow-up (80 ± 20 vs 81 ± 43 months). There were no significant differences between the groups at baseline, at final follow-up, or in the amount of clinical improvement in any of the outcome parameters (P > .05; respectively). CONCLUSION: Performing both mowHTO or lcwDFO yields significant improvement in clinical outcomes if performed at the location of the deformity of varus malalignment. These findings confirm the clinical effectiveness of performing an isolated lcwDFO in femoral-based varus malalignment, which is comparable with that of mowHTO in the correction of varus malalignment.

Elliptical heads result in increased glenohumeral translation along with micro-motion of the glenoid component during axial rotation in total shoulder arthroplasty.

INTRODUCTION: Elliptical-shaped humeral head prostheses have recently been proposed to reflect a more anatomic shoulder replacement. However, its subsequent effect on micro-motion of the glenoid component is still not understood. MATERIALS AND METHODS: Six fresh-frozen, cadaveric shoulders (mean age: 62.7 ± 9.2 years) were used for the study. Each specimen underwent total shoulder arthroplasty using an anatomic stemless implant. At 15°, 30°, 45° and 60° of glenohumeral abduction, 50° of internal and external rotations in the axial plane were alternatingly applied to the humerus with both an elliptical and spherical humeral head design. Glenohumeral translation was assessed by means of a 3-dimensional digitizer. Micro-motion of the glenoid component was evaluated using four high-resolution differential variable reluctance transducer strain gauges, placed at the anterior, posterior, superior, and inferior aspect of the glenoid component. RESULTS: The elliptical head design showed significantly more micro-motion in total and at the superior aspect of glenoid component during external rotation at 15° (total: P = 0.004; superior: P = 0.004) and 30° (total: P = 0.045; superior: P = 0.033) of abduction when compared to the spherical design. However, during internal rotation, elliptical and spherical heads showed similar amounts of micro-motion at the glenoid component at all tested abduction angles. When looking at glenohumeral translation, elliptical and spherical heads showed similar anteroposterior and superoinferior translation as well as compound motion during external rotation at all tested abduction angles. During internal rotation, the elliptical design resulted in significantly more anteroposterior translation and compound motion at all abduction angles when compared to the spherical design (P < 0.05). CONCLUSION: In the setting of total shoulder arthroplasty, the elliptical head design demonstrated greater glenohumeral translation and micro-motion at the glenoid component during axial rotation when compared to the spherical design, potentially increasing the risk for glenoid loosening in the long term. LEVEL OF EVIDENCE: Controlled Laboratory Study.

Clinical outcome and healing rate after meniscal bucket handle tear repair.

BACKGROUND: Reports combining patient-reported outcome measures, clinical evaluation, and radiographic assessment of postoperative healing after arthroscopic repair of bucket-handle meniscal tears (BHMT) are scarce. METHODS: Patients who underwent arthroscopic repair for acute traumatic BHMTs between October 2011 and March 2016 with a minimum follow-up of two years were included. Postoperative outcome scores comprised the International Knee Documentation Society Score (IKDC), Lysholm score, Tegner activity score (TAS), and visual analog scale (VAS) for pain. Clinical meniscal healing failure was assessed according to Barrett's criteria. Side-to-side difference in knee laxity was measured using KT-2000. Radiographic healing was assessed by 3-Tesla magnetic resonance imaging (MRI) and classified according to Henning's criteria at final follow-up. RESULTS: Forty patients with a mean age of 32.0 ± 11.5 years were available for follow-up after 51.8 ± 14.3 months. Revision surgery by means of arthroscopic partial meniscectomy was performed in four patients (10%) prior to the follow-up visit. The clinical healing rate was 83.3% at final follow-up. Mean IKDC score was 82.8 ± 13.8 and Lysholm score was 77.4 ± 24.8. Of all patients, 87.5% reached or exceeded the patient-acceptable symptomatic state (PASS) criteria for the IKDC score at final follow-up. The median TAS was 6 and VAS for pain was 0.46 ± 0.9. Side-to-side difference in knee laxity was higher in patients with concomitant ACL reconstruction (2.1 ± 2.7 mm) compared to isolated BHMTs (1.0 ± 2.0 mm). MR examination showed 69.4% healed, 25.0% partially healed, and 5.6% unhealed menisci. CONCLUSION: Patients who underwent repair for acute traumatic BHMTs achieved good to excellent clinical outcome along with a high rate of meniscal healing at a minimum follow-up of two years. Clinical and radiological healing rates were similarly satisfactory and most patients exceeded the PASS criteria for the IKDC score. Patients were able to reach a high postoperative activity level. LEVEL OF EVIDENCE: Case Series; IV.

Current concepts in acromioclavicular joint (AC) instability - a proposed treatment algorithm for acute and chronic AC-joint surgery.

BACKGROUND: There exists a vast number of surgical treatment options for acromioclavicular (AC) joint injuries, and the current literature has yet to determine an equivocally superior treatment. AC joint repair has a long history and dates back to the beginning of the twentieth century. MAIN BODY: Since then, over 150 different techniques have been described, covering open and closed techniques. Low grade injuries such as Type I-II according to the modified Rockwood classification should be treated conservatively, while high-grade injuries (types IV-VI) may be indicated for operative treatment. However, controversy exists if operative treatment is superior to nonoperative treatment, especially in grade III injuries, as functional impairment due to scapular dyskinesia or chronic pain remains concerning following non-operative treatment. Patients with a stable AC joint without overriding of the clavicle and without significant scapular dysfunction (Type IIIA) may benefit from non-interventional approaches, in contrast to patients with overriding of the clavicle and therapy-resistant scapular dysfunction (Type IIIB). If these patients are considered non-responders to a conservative approach, an anatomic AC joint reconstruction using a hybrid technique should be considered. In chronic AC joint injuries, surgery is indicated after failed nonoperative treatment of 3 to 6 months. Anatomic AC joint reconstruction techniques along with biologic augmentation (e.g. Hybrid techniques, suture fixation) should be considered for chronic high-grade instabilities, accounting for the lack of intrinsic healing and scar-forming potential of the ligamentous tissue in the chronic setting. However, complication and clinical failure rates remain high, which may be a result of technical failures or persistent horizontal and rotational instability. CONCLUSION: Future research should focus on addressing horizontal and rotational instability, to restore native physiological and biomechanical properties of the AC joint.

The 50 most cited studies on posterior tibial slope in joint preserving knee surgery.

PURPOSE: To determine the 50 most cited studies on posterior tibial slope (PTS) in joint preserving knee surgery and assess their level of evidence, objective study quality scores as well as to examine whether the study quality correlated with the citation count and citation density in the top 50 list. METHODS: A literature search on Web of Science was performed to determine the 50 most cited studies on the topic of PTS in joint preserving knee surgery between 1990 and 2022. The studies were evaluated for their bibliographic parameters, level of evidence rating (LOE), citation counts, the Modified Coleman Methodological Score (MCMS), the Methodological Index for Non-Randomized Studies (MINORS), and the Radiologic Methodology and Quality Scale (MQCSRE). RESULTS: Of the top 50 list, 16 studies were published in the American Journal of Sports Medicine. A total of 23 studies were produced in the United States (46%). Of 10 different study types, case control studies (n = 16, 32%) and cadaveric studies (n = 10, 20%) were most common. 15 studies (30%) were purely radiological studies. 6 studies were level II (12%), 23 level III (46%), 15 level IV (30%), and 6 level V studies (12%), respectively. The number of citations ranged from 42 to 447 (mean 105.6 ± 79.2 citations) and showed a mean citation density of 10.3 ± 5.2, composed of the decades 1994 - 2000 (8.3 ± 4.1), 2001 - 2010 (11.1 ± 5.9), 2011 - 2019 (10.1 ± 5.1). Mean quality scores were 55.9 ± 13.0 for MCMS (n = 18), 14.5 ± 3.2 for MINORS (n = 18) and 18.1 ± 3.7 for MQCSRE (n = 20), respectively. High citation counts did not correlate with higher study quality scores (p > 0.05). Radiological studies were not significantly cited more often than non-radiological studies (mean 116.9 ± 88.3 vs. 100.8 ± 75.8 citations; p > 0.05). CONCLUSION: In joint preserving knee surgery, the 50 most cited studies on PTS did not represent a ranking of the highest methodological quality scores. Citation counts and citation density over the past three decades did not significantly differ, even though the number of articles in the presented list multiplied over the same period. This list can serve as a reference tool for orthopedic surgeons aiming to review PTS literature.

Head-Mounted Display Virtual Reality Is Effective in Orthopaedic Training: A Systematic Review.

Purpose: To conduct a systematic review to determine the efficacy of head-mounted display (HMD) virtual reality (VR) in orthopaedic surgical training. Methods: A thorough search was conducted on PubMed for articles published between January 2000 and August 2020. Studies were included if they (1) concerned orthopaedic surgery, (2) dealt with an HMD VR device, (3) the technology was being used for training purposes, and (4) was a randomized control trial (RCT). Results: Eight articles met the inclusion criteria. Analysis of the 8 RCTs reveals 6 of the 8 demonstrating HMD VR to be a superior training method to traditional-based training modules. However, in the remaining 2 articles, authors found no significant difference between the VR group and controls, but showed at least equivalent ability to train novice surgeons. Conclusions: RCTs show promising evidence that HMD VR is an efficacious tool in surgical training for orthopaedic procedures, with most randomized clinical trials showing improvement in novice students/surgeons compared with controls. Clinical Relevance: As VR technology advances, so must the research directed at determining the efficacy of such technologies at educating our novice surgeons. RCTs are already demonstrating the role HMD VR can play in the education of novice orthopaedic surgeons.

Arthroscopic Rotator Cuff Repair with a Fibrin Scaffold Containing Growth Factors and Autologous Progenitor Cells Derived From Humeral cBMA Improves Clinical Outcomes in High Risk Patients.

Purpose: To report the clinical outcomes after biologically augmented rotator cuff repair (RCR) with a fibrin scaffold derived from autologous whole blood and supplemented with concentrated bone marrow aspirate (cBMA) harvested at the proximal humerus. Methods: Patients who underwent arthroscopic RCR with biologic augmentation using a fibrin clot scaffold ("Mega- Clot") containing progenitor cells and growth factors from proximal humerus BMA and autologous whole blood between April 2015 and January 2018 were prospectively followed. Only high-risk patients in primary and revision cases that possessed relevant comorbidities or physically demanding occupation were included. Minimum follow-up for inclusion was 1 year. The visual analog score for pain (VAS), American Shoulder and Elbow Surgeons (ASES), Simple Shoulder Test (SST), Single Assessment Numerical Evaluation (SANE), and Constant-Murley scores were collected preoperatively and at final follow-up. In vitro analyses of the cBMA and fibrin clot using nucleated cell count, colony forming units, and live/dead assays were used to quantify the substrates. Results: Thirteen patients (56.9 ± 7.7 years) were included. The mean follow-up was 26.9 ± 17.7 months (n = 13). There were significant improvements in all outcome scores from the preoperative to the postoperative state: VAS (5.6 ± 2.5 to 3.1 ± 3.2; P < .001), ASES (42.0 ± 17.1 to 65.5 ± 30.6; P < .001), SST (3.2 ± 2.8 to 6.5 ± 4.7; P = .002), SANE (11.5 ± 15.6 to 50.3 ± 36.5; P < .001), and Constant-Murley (38.9 ± 17.5 to 58.1 ± 26.3; P < .001). Six patients (46%) had retears on postoperative MRI, despite all having improvements in pain and function except one. All failures were chronic rotator cuff tears, and all were revision cases except one (1.6 ± 0.5 previous RCRs). The representative sample of harvested cBMA showed an average of 28.5 ± 9.1 × 106 nucleated cells per mL. Conclusions: Arthroscopic rotator cuff repairs that are biologically augmented with a fibrin scaffold containing growth factors and autologous progenitor cells derived from autologous whole blood and humeral cBMA can improve clinical outcomes in primary, as well as revision cases in high-risk patients. However, the incidence of retears remains a concern in this population, demanding further improvements in biologic augmentation. Level of Evidence: IV, therapeutic case series.