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 However, the present short- to mid-term results do not justify ACL reconstruction to be superseded by ACL repair with DIS as the "gold standard" for surgical treatment of ACL tears in the future, even in this subset of patients.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.

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.

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.

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.

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.

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.

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.

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.

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.

Biomechanical comparison of lower trapezius and latissimus dorsi transfer for irreparable posterosuperior rotator cuff tears using a dynamic shoulder model.

BACKGROUND: In the setting of irreparable posterosuperior rotator cuff tears (PSRCTs), lower trapezius transfer (LTT) may be anatomically better positioned for restoring the muscular force couple compared with latissimus dorsi transfer (LDT). The purpose of the study was to evaluate the effect of LTT and LDT on glenohumeral kinematics using a dynamic shoulder model. METHODS: Ten fresh-frozen cadaveric shoulders (mean age: 56.5 ± 17.2 years) were tested using a dynamic shoulder simulator. The maximum abduction angle (MAA), superior humeral head migration (SHM), and cumulative deltoid forces (CDFs) were compared across 4 conditions: (1) native; (2) irreparable PSRCT; (3) LTT using an Achilles tendon allograft; and (4) LDT. MAA and SHM were measured using 3-dimensional motion tracking. CDF was recorded in real time throughout the dynamic abduction motion by load cells connected to actuators. RESULTS: Compared to the native state, the PSRCT resulted in a significant decrease (Δ-24.1°; P < .001) in MAA, with a subsequent significant increase after LTT (Δ13.1°; P < .001) and LDT (Δ8.9°; P < .001). LTT achieved a significantly greater MAA than LDT (Δ4.2°; P = .004). Regarding SHM, both LTT (Δ-9.4 mm; P < .001) and LDT (Δ-5.0 mm; P = .008) demonstrated a significant decrease compared with the PSRCT state. LTT also achieved significantly less SHM compared with the LDT (Δ-4.4 mm; P = .011). Further, only the LTT resulted in a significant decrease in CDF compared with the PSRCT state (Δ-21.3 N; P = .048), whereas LTT and LDT showed similar CDF (Δ-11.3 N; P = .346). However, no technique was able to restore the MAA, SHM, and CDF of the native shoulder (P < .001, respectively). CONCLUSION: LTT and LDT both achieved a significant increase in MAA along with significantly less SHM compared with the PSRCT state. Although LTT required significantly less compensatory deltoid forces compared with the PSRCT state, this was not observed for the LDT. Further, the LTT prevented loss of abduction motion and SHM more sufficiently. In the challenging treatment of irreparable PSRCTs, LTT may restore native glenohumeral kinematics more sufficiently, potentially leading to improved postoperative functional outcomes.

Editorial Commentary: Double-Sling Transfer of Both the Conjoined Tendons and Long Head Biceps Tendon for Glenoid Bone Loss in Patients With Shoulder Instability Shows Biomechanical Benefit in Shoulder Abduction and External Rotation But May Be Insufficient in Mid-Range Arm Positions.

Recurrence of shoulder glenohumeral instability is exacerbated in cases of glenoid bone loss. Surgical bone transfer techniques well address the issue. Innovative soft-tissue tendon transfers may fill the defect plus provide a sling effect. Double-sling transfer of both the conjoined tendons and long head biceps tendon for glenoid bone loss in patients with shoulder instability shows biomechanical benefit in shoulder abduction and external rotation. However, as the sling effect is less pronounced in mid-range arm position, the benefit of double-sling transfer may be insufficient. Moreover, the biomechanical models are limited relative to the complexity of clinical glenohumeral function, and obviously limited to time-zero analysis. We should be careful before we abandon bony augmentation procedures.

Low rate of substantial loss of reduction immediately after hardware removal following acromioclavicular joint stabilization using a suspensory fixation system.

PURPOSE: To evaluate immediate loss of reduction in patients undergoing hardware removal after arthroscopically assisted acromioclavicular (AC) joint stabilization using a high-tensile suture tape suspensory fixation system and to identify risk factors associated with immediate loss of reduction. MATERIALS AND METHODS: Twenty-two consecutive patients with a mean age of 36.4 ± 12.6 years (19-56), who underwent hardware removal 18.2 ± 15.0 months following arthroscopically assisted stabilization surgery using a suspensory fixation system for AC joint injury between 01/2012 and 01/2021 were enrolled in this retrospective monocentric study. The coracoclavicular distance (CCD) as well as the clavicular dislocation/acromial thickness (D/A) ratio were measured on anterior-posterior radiographs prior to hardware removal and immediately postoperatively by two independent raters. Loss of reduction, defined as 10% increase in the CCD, was deemed substantial if the CCD increased 6 mm compared to preoperatively. Constitutional and surgical characteristics were assessed in a subgroup analysis to detect risk factors associated with loss of reduction. RESULTS: Postoperatively, the CCD significantly increased from 12.6 ± 3.7 mm (4.8-19.0) to 14.5 ± 3.3 mm (8.7-20.6 mm) (p < 0.001) while the D/A ratio increased from 0.4 ± 0.3 (- 0.4-0.9) to 0.6 ± 0.3 (1.1-0.1) (p = 0.034) compared to preoperatively. In 10 cases (45%), loss of reduction was identified, while a substantial loss of reduction (> 6 mm) was only observed in one patient (4.5%). A shorter time interval between index stabilization surgery and hardware removal significantly corresponded to immediate loss of reduction (11.0 ± 5.6 vs. 30.0 ± 20.8 months; p = 0.007), as hardware removal within one year following index stabilization was significantly associated with immediate loss of reduction (p = 0.027; relative risk 3.4; odds ratio 11.67). CONCLUSIONS: Substantial loss of reduction after hardware removal of a high-tensile suture tape suspensory fixation system was rare, indicating that the postoperative result of AC stabilization is not categorically at risk when performing this procedure. Even though radiological assessment of the patients showed a statistically significant immediate superior clavicular displacement after this rarely required procedure, with an increased incidence in the first year following stabilization, this may not negatively influence the results of ACJ stabilization in a clinically relevant way. LEVEL OF EVIDENCE: IV.

Excellent clinical and radiological outcomes after both open flake refixation and autologous chondrocyte implantation following acute patella dislocation and concomitant flake fractures.

PURPOSE: To investigate clinical and magnetic resonance (MR) imaging results of patients undergoing patella stabilization with either open flake refixation (oFR) or autologous chondrocyte implantation (ACI) and concomitant soft tissue patella stabilization after sustaining primary, acute patella dislocation with confirmed chondral and/or osteochondral flake fractures. It was hypothesized that refixation will lead to better results than ACI at mid-term follow-up. METHODS: A retrospective chart review was conducted to identify all patients undergoing oFR or ACI after sustaining (osteo-)chondral flake fractures and concomitant soft tissue patella stabilization following primary, acute patella dislocation between 01/2012 and 09/2018 at the author's institution. Patients were excluded if they were aged < 14 years or > 30 and had previous knee surgeries at the index knee. Clinical outcomes were assessed using the Tegner activity score, Kujala score, subjective IKDC score, and the KOOS score at a minimum follow-up of 24 months postoperatively. MR images were assessed using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 knee score. Thirty patients were included in the study, with 16 patients assorted to the oFR group and 14 patients to the ACI group (Follow-up 81%). RESULTS: Demographic data did not show significant group differences (oFR: 6 females, 10 males; age 26.9 ± 5.6 years, FU: 57 months (27-97 months); ACI: 9 females, 5 males; age 25.5 ± 4.9 years, FU: 51 months (29-91 months); n.s.). Defect location was similar in both groups (oFR: 12 × patella/4 × lateral femoral condyle; ACI: 12/2; n.s.). Both groups showed excellent clinical outcomes, with no statistically significant difference between both the groups (oFR group vs. ACI group: Tegner: 5.1 ± 1.8 vs. 5.1 ± 1.4; Kujala: 86.1 ± 12.6 vs. 84.9 ± 9.1; IKDC: 83.8 ± 15.0 vs. 83.6 ± 11.3; KOOS: 83.3 ± 14.0 vs. 83.6 ± 12.0; n.s.). One patient in each group suffered a patella re-dislocation and needed revision surgery. The MOCART 2.0 score showed good results for the oFR group (68.2 ± 11.1) and the ACI group (61.1 ± 16.9) while no significant differences were noted between both the groups. The inter-rater reliability was excellent (0.847). CONCLUSION: Open refixation of (osteo-)chondral fragments in patients after sustaining acute patella dislocation with (osteo)-chondral flake fractures led to good clinical and radiological results at a minimum follow of 24 months, showing that it is a good surgical option in the treatment algorithm. However, if open refixation is not possible, ACI may be an excellent fallback option in these younger patients with equally good clinical and radiological outcomes, but requiring a second minimally invasive surgery. LEVEL OF EVIDENCE: III.

Outcomes of reverse shoulder arthroplasty following failed superior capsular reconstruction.

BACKGROUND: Superior capsular reconstruction (SCR) can be used for massive irreparable rotator cuff tears in the absence of significant degenerative changes; however, those who fail an SCR may require reverse shoulder arthroplasty (RSA). The effect of a previously performed SCR on outcomes following RSA remains unknown. METHODS: Subjects who underwent RSA from May 2015 to January 2021 at 2 separate institutions were retrospectively identified through prospectively collected databases. Patients who underwent RSA after failed SCR were matched to those who underwent RSA after failed rotator cuff repair (RCR) based on the number of previous ipsilateral shoulder procedures (n = 1, 2, ≥3) and secondarily by age within 5 years. American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, Single Assessment Numeric Evaluation (SANE), visual analog scale (VAS) for pain, and Western Ontario Osteoarthritis of the Shoulder index (WOOS) scores were compared between groups. The minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) thresholds were calculated to determine clinically relevant differences between groups. RESULTS: Forty-five patients were included (32 RSA following RCR, 13 following SCR). There were more smokers (P = .001) and worker's compensation cases (P = .034) in the SCR group. The RCR cohort was older (P = .007) and had a greater incidence of mental health (P > .999) and somatic disorders (P = .698), although these did not reach statistical significance. The mean follow-up for the RCR and SCR groups were 24.2 ± 23.3 and 20.4 ± 14.9 months following RSA, respectively (P = .913). The time from index RCR or SCR to RSA were 94.4 ± 22.2 and 89.2 ± 5.3 months, respectively (P = .003). Pre- and postoperative range of motion were similar between groups, as was the overall change in forward flexion (P = .879), abduction (P = .971), and external rotation (P = .968) following RSA. The RCR group had lower postoperative VAS pain (P = .009), higher SANE (P = .015), higher ASES (P = .008), and higher WOOS (P = .018) scores. The percentage achieving the MCID (P = .676) and SCB (P > .999) were similar; however, 56.7% of the RCR group met the SANE PASS threshold compared with 0.0% in the SCR group (P = .005). There were no differences in postoperative complications (P = .698) or revision rates (P = .308) following RSA between cohorts. CONCLUSION: When matched for number of previous procedures to the ipsilateral extremity and age, patients who underwent RSA following failed SCR had worse clinical outcome scores than their RSA following failed RCR counterparts. No patient in the SCR group met the SANE PASS threshold, whereas more than half of the RCR group did.

[Arthroscopic superior capsule reconstruction using a 6 mm thick acellular dermal allograft for irreparable posterosuperior rotator cuff tears]. / Arthroskopische superiore Kapselrekonstruktion mit einem 6 mm dicken azellulären dermalen Allograft bei irreparablen posterosuperioren Rotatorenmanschettenrupturen.

OBJECTIVE: Implantation of an acellular dermal allograft between glenoid and humerus to restore a stable glenohumeral center of rotation in cases of irreparable posterosuperior rotator cuff tears. INDICATIONS: Irreparable posterosuperior rotator cuff tears with low-grade cuff tear arthropathy (Hamada grade 1 and 2) and isolated pseudoparesis for flexion. CONTRAINDICATIONS: Absolute: Infection, nerve lesions (brachial plexus, axillary nerve), concomitant irreparable subscapularis tendon tear, anterosuperior subluxation of the humeral head ("anterosuperior escape"). Relative: Cuff tear arthropathy ≥ Hamada grade 3, fatty infiltration of the infraspinatus muscle ≥ Goutallier grade 2, deficiency of the deltoid muscle, inability to adhere to the rehabilitation program, poor compliance. SURGICAL TECHNIQUE: Arthroscopic fixation of a 6 mm thick acellular dermal allograft with three suture anchors at the superior glenoid rim and a double-row construct at the greater tuberosity. Dorsal and ventral interval closure with side-to-side sutures. POSTOPERATIVE MANAGEMENT: Abduction brace for 6 weeks with passive mobilization. Active motion exercises are commenced at 6 weeks with progression to strengthening exercises after 12 weeks. RESULTS: Between April 2019 and September 2020, 15 patients (5 women and 10 men) underwent arthroscopic superior capsule reconstruction using a 6 mm thick acellular dermal allograft for treatment of irreparable posterosuperior rotator cuff tears. After a mean follow-up of 15.4 ± 5.5 months, there was a significant improvement in active flexion (102°â€¯± 37°preop vs. 143°â€¯± 24°postop; P = 0.001; 95% CI 19.6-63.7), ASES score (45.5 ± 16.1preop vs. 68.2 ± 17.4postop; P < 0.001; 95% CI; 12.9-33.7) and DASH score (57.2 ± 18.6preop vs. 22.0 ± 17.4postop; P < 0.001; 95% CI; -46.0 to 24.7), along with significant pain reduction (4.5 ± 2.0preop vs. 2.5 ± 2.1postop; P = 0.001; 95% CI; -3.2 to 1.1). There were no complications requiring revision surgery.