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Background: Unrepairable massive rotator cuff tears (UMRCTs) are challenging to surgeons owing to the severely retracted rotator cuff musculotendinous tissues and extreme defects in the rotator cuff tendinous tissues. Purpose: To fabricate a tendon stem cell–derived exosomes loaded scaffold (TSC-Exos-S) and investigate its effects on cellular bioactivity in vitro and repair in a rabbit UMRCT model in vivo. Study Design: Controlled laboratory study. Methods: TSC-Exos-S was fabricated by loading TSC-Exos and type 1 collagen (COL-I) into a 3-dimensional bioprinted and polycaprolactone (PCL)–based scaffold. The proliferation, migration, and tenogenic differentiation activities of rabbit bone marrow stem cells (BMSCs) were evaluated in vitro by culturing them in saline, PCL-based scaffold (S), COL-I loaded scaffold (COL-I-S), and TSC-Exos-S. In vivo studies were conducted on a rabbit UMRCT model, where bridging was repaired with S, COL-I-S, TSC-Exos-S, and autologous fascia lata (FL). Histological and biomechanical analyses were performed at 8 and 16 weeks postoperatively. Results: TSC-Exos-S exhibited reliable mechanical strength and subcutaneous degradation, which did not occur before tissue regeneration. TSC-Exos-S significantly promoted the proliferation, migration, and tenogenic differentiation of rabbit BMSCs in vitro. In vivo studies showed that UMRCT repaired with TSC-Exos-S exhibited significant signs of tendinous tissue regeneration at the bridging site with regard to specific collagen staining. Moreover, no significant differences were observed in the histological and biomechanical properties compared with those repaired with autologous FL. Conclusion: TSC-Exos-S achieved tendinous tissue regeneration in UMRCT by providing mechanical support and promoting the trend toward tenogenic differentiation. Clinical Relevance: The present study proposes a potential strategy for repairing UMRCT with severely retracted musculotendinous tissues and large tendinous tissue defects. [ABSTRACT FROM AUTHOR]

Background: An anterior cruciate ligament (ACL) injury accompanied by patellar instability (PI) is a topic that has gained orthopaedic surgeons' attention recently. Untreated PI is reportedly associated with worse clinical outcomes after isolated ACL reconstruction (ACLR) in patients after an ACL injury with PI. Nevertheless, the appropriate surgical approach and its long-term therapeutic effects in these patients remain unclear. Purpose: (1) To compare the clinical and radiological outcomes between isolated ACLR (iACLR) and combined ACLR and medial patellofemoral ligament reconstruction (cAMR) in patients after an ACL injury with PI and (2) to explore the correlations between these 2 procedures and clinical and radiological outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 106 patients diagnosed with an ACL injury accompanied by PI between January 2016 and April 2021 were analyzed in this study. There were 34 patients excluded because of missing postoperative radiological data. Among the remaining 72 patients, 34 patients underwent iACLR, while 38 patients underwent cAMR. Demographic characteristics, intraoperative findings, and patient-reported outcomes (Lysholm score, subjective International Knee Documentation Committee score, and Tegner activity score) were prospectively collected. Patellar alignment parameters and worsening patellofemoral osteoarthritis (PFOA) features (evaluated with the modified Whole-Organ Magnetic Resonance Imaging Score) were analyzed longitudinally on magnetic resonance imaging. The Kujala score was used to evaluate the functional recovery of the patellofemoral joint, and redislocations of the patella were prospectively recorded. Finally, multivariate logistic regression analysis was used to explore the correlations between these 2 procedures and clinical (not achieving the minimal detectable change [MDC] for the Lysholm score) and radiological (worsening PFOA features) outcomes. Results: The mean follow-up duration was 28.9 ± 6.2 and 27.1 ± 6.8 months for the iACLR and cAMR groups, respectively (P =.231). Significantly higher Lysholm scores (88.3 ± 9.9 vs 82.1 ± 11.1, respectively; P =.016) and subjective International Knee Documentation Committee scores (83.6 ± 11.9 vs 78.3 ± 10.2, respectively; P =.046) were detected in the cAMR group compared with the iACLR group postoperatively. The rates of return to preinjury sports were 20.6% and 44.7% in the iACLR and cAMR groups, respectively (difference, 24.1% [95% CI, 3.3%-45.0%]; P =.030). Moreover, the rates of worsening PFOA features were 44.1% and 18.4% in the iACLR and cAMR groups, respectively (difference, 25.7% [95% CI, 4.9%-46.4%]; P =.018). In addition, significantly higher Kujala scores (87.9 ± 11.3 vs 80.1 ± 12.0, respectively; P =.006), lower redislocation rates (0.0% vs 11.8%, respectively; difference, 11.8% [95% CI, 0.9%-22.6%]; P =.045), and significantly better patellar alignment were detected in the cAMR group compared with the iACLR group postoperatively. Furthermore, multivariate logistic regression analysis determined that iACLR and partial lateral meniscectomy were significantly correlated with not achieving the MDC for the Lysholm score and worsening PFOA features in our study population. Conclusion: In patients after an ACL injury with PI, cAMR yielded better clinical and radiological outcomes compared with iACLR, with better patellar stability and a lower proportion of worsening PFOA features. Furthermore, not achieving the MDC for the Lysholm score and worsening PFOA features were significantly correlated with iACLR and partial lateral meniscectomy. Our study suggests that cAMR may be a more appropriate procedure for patients after an ACL injury with PI, which warrants further high-level clinical evidence. [ABSTRACT FROM AUTHOR]

Background: Although Hill-Sachs lesions (HSLs) are assumed to be influenced by glenoid characteristics in the context of bipolar bone loss, little is known about how glenoid concavity influences HSL morphology. Purpose: To investigate the relationship between the native glenoid depth and HSL morphological characteristics. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Computed tomography images of bilateral shoulders from 151 consecutive patients with traumatic unilateral anterior shoulder instability were retrospectively reviewed. Patients were categorized into flat (<1 mm), moderate (1-2 mm), and deep (>2 mm) groups based on the native glenoid depth measured from the contralateral unaffected shoulder. The HSL morphological characteristics included size (depth, width, length, and volume), location (medial, superior, and inferior extent), and orientation (rim and center angle). The glenoid characteristics included diameter, depth, version, and bone loss. The patient, glenoid, and HSL morphological characteristics were compared among the 3 depth groups. Subsequently, the independent predictors of some critical HSL morphological characteristics were determined using multivariate stepwise regression. Results: After exclusion of 55 patients, a total of 96 patients were enrolled and classified into the flat group (n = 31), moderate group (n = 35), and deep group (n = 30). Compared with those in the flat group, patients in the deep group were more likely to have dislocation (38.7% vs 93.3%; P =.009) at the primary instability and had a significantly larger number of dislocations (1.1 ± 1.0 vs 2.2 ± 1.8; P =.010); moreover, patients in the deep group had significantly deeper, wider, larger volume, more medialized HSLs and higher incidences of off-track HSLs (all P ≤.025). No significant differences were detected among the 3 groups in HSL length, vertical position, and orientation (all P ≥.064). After adjustment for various radiological and patient factors in the multivariate regression model, native glenoid depth remained the strongest independent predictor for HSL depth (β = 0.346; P <.001), width (β = 0.262; P =.009), volume (β = 0.331; P =.001), and medialization (β = −0.297; P =.003). Conclusion: The current study sheds light on the association between native glenoid depth and the morphology of HSLs in traumatic anterior shoulder instability. Native glenoid depth was independently and positively associated with HSL depth, width, volume, and medialization. Patients with deeper native glenoids were more likely to have off-track HSLs and thus require more attention in the process of diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Background: Adipokines represent a spectrum of bioactive molecules that could modulate fibroblastic and inflammatory processes. The role of adipokines in the pathogenesis of frozen shoulder (FS), a common musculoskeletal disorder characterized by chronic inflammation, remains obscure. Purpose: To evaluate whether adipokines contribute to the pathogenic mechanisms of FS and to evaluate any potential correlation of adipokines with patients' symptoms. Study Design: Controlled laboratory study. Methods: Shoulder capsule specimens were obtained from 10 patients with FS and 10 patients with shoulder instability (control group). The specimens were dyed using hematoxylin and eosin and immunohistochemically assessed with antibodies targeting adipokines, collagen I, collagen III, and tumor necrosis factor α. Immunoreactivity was graded from "no" to "strong" in a blinded manner. Reverse transcription–quantitative real-time polymerase chain reaction (RT-qPCR) analysis was conducted. Before the surgery, patient-reported frequency of pain, severity of pain, stiffness, and shoulder range of motion were documented. Results: In comparison with the control group, patients with FS had significantly greater pain frequency, pain severity, and stiffness and more limited shoulder range of motion (P <.001). Hematoxylin and eosin- and Masson trichrome–stained samples from the FS group displayed hypercellularity and increased collagen fibers. Immunohistochemistry and RT-qPCR analyses indicated that expression of adipokines was significantly increased in FS capsules compared with the control group. The expression of collagen I, collagen III, and tumor necrosis factor α was also increased in FS capsules. No significant correlation was noted between adipokine expression and patient-reported outcomes in the control group, whereas in patients with FS, adiponectin expression was correlated with pain frequency (r = 0.78; P =.01) and stiffness (r = 0.73; P =.02). Visfatin was also correlated with pain frequency (r = 0.70; P =.02). Conclusion/Clinical Relevance: This study indicated a potential role for adipokines in the pathogenesis of FS and demonstrated a correlation between adipokine expression and patients' pain and stiffness. [ABSTRACT FROM AUTHOR]

Background: Rotator cuff tear size, fatty infiltration, and scapular morphology are correlated with tendon healing and functional outcomes after arthroscopic repair; however, the association between anteroposterior acromial coverage and the clinical outcomes of anteroposterior massive rotator cuff tears (AP-MRCTs; involving all 3 tendons) remains unclear. Purpose: To identify the association between AP acromial coverage and functional and radiological outcomes after arthroscopic repair of AP-MRCTs. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 98 patients who underwent arthroscopic repair of AP-MRCTs between January 2015 and December 2020 were included in the study and classified according to whether anterior acromial coverage (AAC) was anterior (46 patients; positive AAC group) or posterior (52 patients; negative AAC group) to the scapular line on true lateral shoulder radiographs. Demographic characteristics, surgical details, and functional outcomes were prospectively collected. Acromial morphological features, global tear extension (GTE), the global fatty infiltration index (GFII), tendon integrity after repair, proximal humeral migration, and glenohumeral abduction were measured and calculated on radiographs or magnetic resonance imaging scans preoperatively and at 2 years postoperatively. Multivariate logistic regression was performed to identify the independent risk factors of a rotator cuff retear. Results: The positive AAC group showed larger AAC, posterior acromial tilt, and anterior acromial slope as well as smaller posterior acromial coverage compared with the negative AAC group. Postoperatively, the American Shoulder and Elbow Surgeons score (82.5 ± 8.3 vs 77.2 ± 11.5, respectively; P =.013), active abduction (157.8°± 27.1° vs 142.7°± 39.6°, respectively; P =.048), and glenohumeral abduction (45.6°± 10.4° vs 39.7°± 14.9°, respectively; P =.041) in the positive AAC group were significantly higher than those in the negative AAC group, while the retear rate (23.9% vs 44.2%, respectively; P =.035) and proximal humeral migration (1.7 ± 1.0 vs 2.3 ± 1.2 mm, respectively; P =.006) were significantly lower in the positive AAC group than in the negative AAC group. Smaller AAC (odds ratio [OR], 0.93 [95% CI, 0.87-1.00]; P =.040), larger GTE (OR, 1.03 [95% CI, 1.01-1.06]; P =.017), and a higher GFII (OR, 3.49 [95% CI, 1.09-11.19]; P =.036) were associated with an increased risk of a rotator cuff retear. Conclusion: Increased AAC was associated with a lower retear rate and better functional outcomes after arthroscopic repair of AP-MRCTs. A preliminary risk evaluation integrating GTE, the GFII, and AAC is recommended to consider the necessity of additional procedures for patients in need of arthroscopic rotator cuff repair. [ABSTRACT FROM AUTHOR]

Background: Tibial plateau fractures require anatomical reduction and stable fixation to achieve satisfactory results. In addition, addressing any related injuries is of paramount importance. Arthroscopic reduction and internal fixation (ARIF) has been promoted as a possible technique to treat tibial plateau fractures. Purpose: To compare the effectiveness of ARIF with this modified reducer and open reduction and internal fixation (ORIF) for Schatzker types II and III tibial plateau fractures. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively reviewed 68 patients who were treated for Schatzker type II or III tibial plateau fractures between August 1, 2014, and October 31, 2018. Patients were categorized into the ARIF (n = 33) and ORIF groups (n = 35). The groups were compared regarding intra-articular injuries, duration of hospital stay, complications, and clinical outcomes—including the International Knee Documentation Committee (IKDC) score, the Hospital for Special Surgery (HSS) score, and range of motion (ROM). The paired t test was used to compare preoperative and postoperative data, and the chi-square test was used to compare the IKDC and HSS scores. Results: The median follow-up period was 36 months (26-40 months). Additional intra-articular lesions were found in 29 patients—21 in the ARIF group and 8 in the ORIF group (P =.02). A significant difference was observed in the duration of hospital stay—3.58 ± 1.46 days for the ARIF group and 4.57 ± 1.12 days for the ORIF group (t = –3.169; P =.002). All fractures healed within 3 months after surgery. The complication rate for all patients was 11%, with no significant difference between the ARIF and ORIF groups (t = 1.244; P =.265). At the final follow-up, there were no significant differences between the 2 groups in the IKDC score, HSS score, and ROM (P >.05 for all). Conclusion: ARIF with a modified reducer was found to be an effective, reliable, and safe procedure for the treatment of Schatzker types II and III tibial plateau fractures. Both ARIF and ORIF provided equally good results, while ARIF offered a more precise evaluation and reduced the duration of hospital stay. [ABSTRACT FROM AUTHOR]

Background: High-grade knee laxity and excessive anterior tibial subluxation (ATS) are correlated with poor clinical outcomes in patients with anterior cruciate ligament (ACL) deficiency and share similar risk factors; however, the association between excessive ATS and high-grade knee laxity remains unclear. Purpose: To identify the association between excessive ATS and high-grade knee laxity in patients with ACL deficiency and determine the possibility that ATS can predict high-grade knee laxity. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 226 patients who underwent ACL reconstruction between May 2018 and March 2022 were analyzed in the present study; the high-grade group consisted of 113 patients who had a grade 3 result on the preoperative anterior drawer test, Lachman test, or pivot-shift test while under anesthesia, and the low-grade group consisted of 113 matched patients. The ATS values for medial and lateral compartments (ATSMC and ATSLC) were measured on magnetic resonance imaging while patients relaxed the quadriceps in the supine position under no anesthesia. The optimal cutoff values of ATSMC and ATSLC for high-grade knee laxity were determined using receiver operating characteristic curves. Univariate and multivariate logistic regression analyses with stratification were performed to identify the association between excessive ATS and high-grade knee laxity. Results: Compared with the low-grade group, the high-grade group had a longer time from injury to surgery; higher rates of medial meniscus posterior horn tear (MMPHT), lateral meniscus posterior horn tear (LMPHT), and anterolateral ligament (ALL) abnormality; and larger lateral tibial slope, ATSMC, and ATSLC. The optimal cutoff value was 2.6 mm (sensitivity, 52.2%; specificity, 76.1%) for ATSMC and 4.5 mm (sensitivity, 67.3%; specificity, 64.6%) for ATSLC in predicting high-grade knee laxity. After adjustment for covariates, ATSLC ≥4.5 mm (odds ratio [OR], 2.94; 95% CI, 1.56-5.55; P =.001), MMPHT (OR, 2.62; 95% CI, 1.35-5.08; P =.004), LMPHT (OR, 2.39; 95% CI, 1.20-4.78; P =.014), and ALL abnormality (OR, 2.09; 95% CI, 1.13-3.89; P =.019) were associated with high-grade knee laxity. The association between excessive ATSLC and high-grade knee laxity was validated in patients with acute ACL injury as well as those with chronic ACL injury. Conclusion: Excessive ATSLC was associated with high-grade knee laxity in patients who had ACL deficiency, with a predictive cutoff value of 4.5 mm. This study may help surgeons estimate the degree of knee instability more accurately before anesthesia and may facilitate preliminary surgical decision-making, such as appropriate graft choices and consideration of extra-articular augmentation. [ABSTRACT FROM AUTHOR]

Background: The accurate evaluation of rotator cuff (RC) fatty degeneration after tears is critical for appropriate surgical decision making and prognosis. However, there is currently no reliable and practical tool to reflect the global fatty infiltration (Global-FI) throughout the 3-dimensional (3D) volumetric RC muscles. Purpose: (1) To determine the correlations between 2 modified assessment tools and the Global-FI and their predictive performances and reliabilities for Global-FI prediction, and (2) to compare these predictive parameters with those of the conventional tool using a single scapular Y-view slice. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: A total of 49 patients with full-thickness RC tears scheduled to undergo arthroscopic repairs were included, and their surgical shoulders underwent 6-point Dixon magnetic resonance imaging preoperatively. The Global-FI was measured by calculating the 3D-volumetric fat fraction (FF) of the whole supraspinatus muscle through all acquired oblique sagittal slices. As a commonly used radiological landmark, the scapular Y-view was used to evaluate single-plane fatty infiltration (Y-FI) by calculating the FF in 1 slice, defined as the conventional assessment tool. Two modified assessment tools expand the analytic imaging by integrating the FFs from the scapular Y-view slice and its neighboring slices, which were calculated by averaging the FFs of these 3 slices (meanY3-FI) and accumulating local 3D-volumetric FFs from 3 slices (volY3-FI), respectively. The correlations between 3 assessment tools and the Global-FI were analyzed, and the predictive performance for Global-FI prediction using these tools was determined by goodness of fit and agreement. Moreover, the inter- and intraobserver reliabilities of these assessment tools were evaluated. Similar analyses were performed in the small-medium, large, or massive tear subgroups. Results: The Y-FI was significantly higher than the Global-FI in all cases and tear size subgroups, while the 2 modified assessment tools (meanY3-FI and volY3-FI) did not significantly differ from the Global-FI. All assessment tools were significantly correlated with the Global-FI, but the meanY3-FI and volY3-FI showed stronger correlations than the Y-FI, which was also determined in different tear sizes. Moreover, the regression models of the meanY3-FI and volY3-FI showed superior goodness of fit to Y-FI in Global-FI prediction in all cases and subgroups, with larger coefficients of determination (R 2) and smaller root mean square errors. The predicted Global-FI using the regression model of volY3-FI had the best agreement with the measured Global-FI, followed by the meanY3-FI, both showing smaller biases and standard deviation of the percentage difference between predicted- and measured Global-FI than the conventional Y-FI. In addition, the 2 modified assessment tools achieved better interobserver and intraobserver reliabilities than the conventional tool in all cases and subgroups. Conclusion: Two modified assessment tools (meanY3-FI and volY3-FI) were comparable with the Global-FI of the whole supraspinatus muscle, showing stronger correlations with the Global-FI and better predictive performances and reliabilities than the conventional tool (Y-FI). Moreover, the volY3-FI was slightly superior to meanY3-FI in the predictive performance and reliability. [ABSTRACT FROM AUTHOR]

Background: Poor tendon-to-bone healing in chronic rotator cuff tears (RCTs) is related to unsatisfactory outcomes. Exosomes derived from mesenchymal stem cells reportedly enhance rotator cuff healing. However, the difficulty in producing exosomes with a stronger effect on enthesis regeneration must be resolved. Purpose: To study the effect of exosomes derived from kartogenin (KGN)-preconditioned human bone marrow mesenchymal stem cells (KGN-Exos) on tendon-to-bone healing in a rat model of chronic RCT. Study Design: Controlled laboratory study. Methods: Exosome-loaded sodium alginate hydrogel (SAH) was prepared. Moreover, exosomes were labeled with 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindotricarbocyanine iodide (DiR) or 1,1′-dioctadecyl-3,3,3′3′-tetramethylindocarbocyanine perchlorate (Dil) for in vivo tracking. Bilateral rotator cuff repair (RCR) was conducted in an established chronic RCT rat model. A total of 66 rats were randomized to control, untreated exosome (un-Exos), and KGN-Exos groups to receive local injections of pure SAH, un-Exos, or KGN-Exos SAH at the repaired site. The presence of DiR/Dil-labeled exosomes was assessed at 1 day and 1 week, and tendon-to-bone healing was evaluated histologically, immunohistochemically, and biomechanically at 4 and 8 weeks. Results: Both un-Exos and KGN-Exos exhibited sustained release from SAH for up to 96 hours. In vivo study revealed that un-Exos and KGN-Exos were localized to the repaired site at 1 week. Moreover, the KGN-Exos group showed a higher histological score and increased glycosaminoglycan and collagen II expression at 4 and 8 weeks. In addition, more mature and better-organized collagen fibers with higher ratios of collagen I to collagen III were observed at 8 weeks in the tendon-to-bone interface compared with those in the control and un-Exos groups. Biomechanically, the KGN-Exos group had the highest failure load (28.12 ± 2.40 N) and stiffness (28.57 ± 2.49 N/mm) among the 3 groups at 8 weeks. Conclusion: Local injection of SAH with sustained KGN-Exos release could effectively promote cartilage formation as well as collagen maturation and organization for enthesis regeneration, contributing to enhanced biomechanical properties after RCR. Clinical Relevance: KGN-Exos injection may be used as a cell-free therapeutic option to accelerate tendon-to-bone healing in chronic RCT. [ABSTRACT FROM AUTHOR]

Background: Nonrigid fixation techniques have been recently introduced in free bone block (FBB) procedures to treat substantial glenoid bone loss in patients with anterior shoulder instability. However, the radiological and histological effectiveness of nonrigid fixation versus conventional rigid fixation have not been comprehensively understood in vivo. Purpose: To (1) explore the radiological and histological characteristics of nonrigid fixation for FBB procedures in a rabbit model of glenoid defects and (2) further compare them with those of conventional rigid fixation. Study Design: Controlled laboratory study. Methods: Unilateral shoulder glenoid defects were created in 36 mature New Zealand White rabbits, of which 24 underwent FBB procedures using allogenic iliac crest bone and were randomly divided into rigid fixation (RF) and nonrigid fixation (N-RF) groups, with the remaining divided into 2 control groups: 6 with sham surgery for glenoid defects (GD group) and 6 native glenoids (normal group). In the RF and N-RF groups, 6 rabbits were sacrificed at 6 or 12 weeks postoperatively for radiological and histological analyses of the reconstructed glenoid, and all rabbits in the GD and normal groups were sacrificed at 12 weeks. The radiological glenoid morphology was evaluated via micro–computed tomography. Moreover, the graft-glenoid healing and graft remodeling processes were determined using histological staining. Results: At 6 weeks, both the N-RF and RF groups had similarly improved radiological axial radian and en face area of the glenoid compared with the GD group, but the N-RF group showed superiority in restoration of the glenoid radian and area compared with the RF group at 12 weeks, with the native glenoid as the baseline. Histologically, the bone graft in both groups was substantively integrated into the deficient glenoid neck at 6 and 12 weeks, showing similar osseous healing processes at the graft-glenoid junction. Moreover, the bone graft histologically presented similar regenerated vascular density, total graft bone, and integrated graft bone in both groups. In contrast, the N-RF group had a different remodeling profile on radiological and histological analyses regarding regional bone resorption, mineralization, and fibrous tissue replacement during osseointegration. Conclusion: Compared with rigid fixation, nonrigid fixation resulted in superior reconstructed glenoid morphology radiologically and similar graft-glenoid osseous healing histologically, showing different graft remodeling profiles of regional bone resorption, mineralization, and fibrous tissue replacement. Clinical Relevance: The nonrigid fixation technique can be feasible for FBB procedures to treat glenoid bone loss in anterior shoulder instability. More clinical evidence is required to determine its pros and cons compared with conventional rigid fixation. [ABSTRACT FROM AUTHOR]

Background: As an alternative to the Latarjet procedure, the arthroscopic free bone block (FBB) procedure combined with dynamic anterior stabilization (DAS) has been recently proposed to provide both glenoid augmentation and a tendon sling effect for treating anterior shoulder instability (ASI) with glenoid bone loss. Purpose: To evaluate the clinical and radiological outcomes of FBB-DAS for ASI with glenoid bone loss. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent arthroscopic FBB-DAS for ASI with >15% glenoid bone loss between February 2017 and March 2020 were screened and enrolled in this study. Clinical outcome measures were assessed preoperatively and at a minimum 2-year follow-up, including recurrence, complications, shoulder functional scores, range of motion, and return to sports. Postoperative computed tomography and magnetic resonance imaging were also performed. Results: Of a total of 65 patients with a mean follow-up of 46.1 ± 13.1 months, no patients experienced a recurrent dislocation or subluxation postoperatively, while 2 had a positive anterior apprehension test (3.1%). Additionally, 2 patients (3.1%) experienced complications of hematoma and shoulder stiffness, respectively. The mean visual analog scale score, American Shoulder and Elbow Surgeons score, Rowe score, and Oxford Shoulder Instability Score all improved significantly from 3.2 ± 2.4, 75.0 ± 18.9, 43.6 ± 27.3, and 33.8 ± 9.0 preoperatively to 1.3 ± 0.8, 95.1 ± 8.0, 95.5 ± 7.8, and 14.8 ± 3.5 at final follow-up, respectively (all P <.001). No difference was detected in range of motion except for 8.1° and 7.5° external rotation limitations in adduction and abduction, respectively. There were 62 patients (95.4%) who returned to sports, and 54 patients (83.1%) returned to the preinjury level. The transferred biceps tendon was intact in all 59 patients who completed radiological examination at the latest follow-up. Good bone healing was achieved in 98.3% of patients, and the glenoid bone defect decreased from 18.1% to 4.9%. Osseous and labral glenoids were significantly enlarged in width and depth on the latest magnetic resonance imaging (all P <.001). Conclusion: Arthroscopic FBB-DAS provided satisfactory clinical and radiological outcomes for ASI with glenoid bone loss. Despite slight external rotation restrictions, it achieved low recurrence and complication rates, excellent shoulder functional scores, a high return-to-sports rate, and favorable graft healing and remodeling. [ABSTRACT FROM AUTHOR]

Background: The glenoid track concept has been widely used to assess the risk of instability due to bipolar bone loss. The glenoid track width was commonly used as 83% of the glenoid width to determine if a lesion was on-track or off-track. However, the value was obtained under static conditions, and it may not be able to reflect the actual mechanism of traumatic dislocation during motion. Purpose: To compare the glenoid track width under dynamic and static conditions using a dual-fluoroscopic imaging system. Study Design: Controlled laboratory study. Methods: In total, 40 shoulders of 20 healthy volunteers were examined for both dynamic and static tests within a dual-fluoroscopic imaging system at 5 different arm positions: 30°, 60°, 90°, 120°, and 150° of abduction, keeping the shoulder at 90° of external rotation. The participants performed a fast horizontal arm backswing for dynamic tests while keeping their arm in maximum horizontal extension for static tests. Computed tomography scans were used to create 3-dimensional models of the humerus and scapula for 2-dimensional to 3-dimensional image registration. Magnetic resonance imaging scans were obtained to delineate the medial margin of the rotator cuff insertion. The glenoid track width was measured as the distance from the anterior rim of the glenoid to the medial margin of the rotator cuff insertion and compared between static and dynamic conditions. Results: The mean glenoid track widths at 30°, 60°, 90°, 120°, and 150° of abduction were significantly smaller under dynamic conditions (88%, 81%, 72%, 69%, and 68% of the glenoid width) than those under static conditions (101%, 92%, 84%, 78%, and 77% of the glenoid width) (all P <.001). The glenoid track width significantly decreased with the increasing abduction angles in the range of 30° to 120° under static conditions (all P <.003) and 30° to 90° under dynamic conditions (all P <.001). Conclusion: A smaller dynamic-based value should be considered for the glenoid track width when distinguishing on-track/off-track lesions. Clinical evidence is needed to establish the superiority of the dynamic-based value over the static-based value as an indicator for augmentation procedures. Clinical Relevance: Some off-track lesions might be misclassified as on-track lesions when the original commonly used static-based value of 83% is used as the glenoid track width. [ABSTRACT FROM AUTHOR]

Objective: To propose a new method for glenoid bone loss measurement, the constellation technique (CST); determine its reliability and accuracy; and compare the validity of CST with that of the conventional technique (CVT) and standard measurements for ratio calculation. Materials and Methods: Sixty shoulders with intact glenoids and no glenohumeral instability and arthritis underwent CT scans. Simulated osteotomies were conducted on the 3D models of glenoids at two cutting locations, expressed as clock face times (2:30–4:20; 1:30–5:00). Two experienced surgeons compared three methods for glenoid bone loss measurement; CVT (best-fit circle), CST ('5S' steps), and standard measurement. Eight undergraduates remeasured five randomly chosen shoulders with moderate to severe bone loss. Intraclass correlation coefficients (ICCs) were calculated for raters. Results: With a defect range between 2:30 and 4:20, all 60 glenoids demonstrated minimal bone loss (< 15%); while between 1:30 and 5:00, 42 shoulders were with moderate bone loss (15–20%), and 18 shoulders with severe bone loss (≥ 20%). For experienced raters, no significant differences were noted between protocos for all categories of bone loss (p ≥ 0.051), with good inter- and intraobserver reliability indicated by ICC. For novice raters, post hoc Tukey analysis found that CST was more accurate in one patient with a standard mean bone loss of 23.2% ± 1.9% compared with CVT. Conclusion: The CST turned the key step of glenoid defect evaluation from deciding an en face view to determining the glenoid inferior rim. The protocol is simple, accurate, and reproducible, especially for novice raters. [ABSTRACT FROM AUTHOR]

Background: Bridging rotator cuff tendon defects with a patch is a reasonable treatment for massive rotator cuff tears (MRCTs). However, the poor outcomes associated with routine patch repair have prompted exploration into superior bridging techniques and graft structures. Purpose: To detect whether dual-suspensory reconstruction using a banded graft would be superior to routine bridging using a patch graft to treat MRCTs and to detect the comparative effectiveness of patellar tendon (PT) and fascia lata (FL) grafts in dual-suspensory reconstruction. Study Design: Controlled laboratory study. Methods: Unilateral chronic MRCTs were created in 72 mature male New Zealand White rabbits, which were randomly divided into 3 groups: (1) patch bridging repair using rectangular FL autograft (PR-FL), (2) dual-suspensory bridging reconstruction using banded FL autograft (DSR-FL), and (3) dual-suspensory bridging reconstruction using banded PT autograft (DSR-PT). In each group, the mean failure load and stiffness of the cuff-graft-humerus (C-G-H) complexes of 6-week and 12-week specimens were recorded, with the failure modes and sites noted. Moreover, cuff-to-graft and graft-to-bone interface healing and graft substance remodeling of the complexes were histologically evaluated (via hematoxylin and eosin, Picrosirius red, Masson trichrome, and Safranin O/fast green staining) at 6 and 12 weeks to assess integrations between the bridging constructs and the native bone or rotator cuff tendons. Results: The DSR-PT group had the greatest mean failure loads and stiffness of the C-G-H complexes at 6 and 12 weeks (41.81 ± 7.00 N, 10.34 ± 2.68 N/mm; 87.62 ± 9.20 N, 17.98 ± 1.57 N/mm, respectively), followed by the DSR-FL group (32.04 ± 5.49 N, 8.20 ± 2.27 N/mm; 75.30 ± 7.31 N, 14.39 ± 3.29 N/mm, respectively). In the DSR-PT and DSR-FL groups, fewer specimens failed at the graft-to-bone junction and more failed at the cuff-to-graft junction, but both groups had higher median failure loads at 6 and 12 weeks (DSR-PT: cuff-to-graft junction, 37.80 and 83.76 N; graft-to-bone junction, 45.46 and 95.86 N) (DSR-FL: cuff-to-graft junction, 28.52 and 67.68 N; graft-to-bone junction, 37.92 and 82.18 N) compared with PR-FL (cuff-to-graft junction, 27.17 and 60.04 N; graft-to-bone junction, 30.12 and 55.95 N). At 12 weeks, the DSR-FL group had higher median failure loads at graft substance (72.26 N) than the PR-FL group (61.27 N). Moreover, the PR-FL group showed more inflammatory responses at the 2 healing interfaces and the graft substance in the 6-week specimens and subsequently displayed poorer interface healing (assessed via collagen organization, collagen maturity, and fibrocartilage regeneration) and graft substance remodeling (assessed via collagen organization and maturity) in 12-week specimens compared with the DSR-PT and DSR-FL groups. Superior interface healing and substance remodeling processes were observed in the DSR-PT group compared with the DSR-FL group. Conclusion: When compared with routine patch repair, the dual-suspensory reconstructions optimized biomechanical properties and improved interface healing and graft substance remodeling for bridging MRCTs. Furthermore, the dual-suspensory technique using the PT graft presented superior histological and biomechanical characteristics than that using FL. Clinical Relevance: The dual-suspensory reconstruction technique using banded tendon grafts may enhance bridging constructs for MRCTs in humans, warranting further investigations of clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: Anterolateral structure augmentation (ALSA) has been applied to prevent residual rotatory instability and lower clinical failure rates after anterior cruciate ligament (ACL) reconstruction (ACLR); however, the effect of combined ALSA on the maturity of ACL grafts remains unknown. Purpose: To evaluate the graft maturity and patient–reported outcomes in patients who underwent double–bundle ACLR with or without ALSA. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 92 patients who underwent double–bundle ACLR between January 2016 and July 2019 were included in the present study—44 patients with isolated ACLR (ACLR group) and 48 patients with combined ACLR and ALSA (ALSA group). Demographic characteristics, intraoperative findings, and patient–reported outcomes were prospectively collected. On postoperative magnetic resonance imaging at the 2–year follow–up, the signal–to–noise quotient (SNQ) values were separately calculated for 6 sections of the ACL graft, including the femoral intratunnel graft (FTG), intra–articular graft (IAG), and tibial intratunnel graft (TTG) of the anteromedial bundle (AMB) and the posterolateral bundle (PLB). Superior graft maturity was usually indicated by lower SNQ values. Results: The rates of return to preinjury sports were 47.9% and 27.3% in the ALSA and ACLR groups, respectively (difference, 20.6% [95% CI, 1.3%-40%]; P =.042). The AMB demonstrated significantly lower SNQ values in the ALSA group than in the ACLR group (FTG, 7.04 ± 3.65 vs 9.44 ± 4.51 [ P =.006]; IAG, 6.62 ± 4.19 vs 8.77 ± 5.92 [ P =.046]; TTG, 6.93 ± 3.82 vs 8.75 ± 4.55 [ P =.040]). The SNQ values were significantly lower in the ALSA group for 2 of the 3 sections of the PLB (IAG, 7.73 ± 4.61 vs 9.88 ± 5.61 [ P =.047]; TTG, 5.88 ± 3.10 vs 8.57 ± 4.32 [ P =.001]). Partial lateral meniscectomy was correlated with higher SNQ values of the TTG in the AMB (β = 0.27; P =.009) and the PLB (β = 0.25; P =.008), with both groups pooled. Higher body mass index, smaller ACL graft–Blumensaat line angles, larger AMB graft diameters, and lower postoperative Tegner scores were also associated with inferior maturity in specific regions of the ACL graft. Conclusion: A combination of ACLR and ALSA is a desirable option to improve the maturity of ACL grafts for patients who are young or expected to return to pivoting sports. Meanwhile, further investigations with higher levels of evidence and longer periods of follow–up are warranted. [ABSTRACT FROM AUTHOR]

Background: Exosomes derived from mesenchymal stromal cells (MSCs) reportedly enhance the healing process. However, no studies have investigated the effect of exosomes from infrapatellar fat pad (IPFP) MSCs on tendon-bone healing and intra-articular graft remodeling after anterior cruciate ligament reconstruction (ACLR). Purpose: To evaluate the in vivo effect of exosomes from IPFP MSCs on tendon-bone healing and intra-articular graft remodeling in a rat model of ACLR. Study Design: Controlled laboratory study. Methods: A total of 90 skeletally mature male Sprague Dawley rats underwent unilateral ACLR using an autograft. All rats were randomly divided into 3 groups: sham injection (SI) group (n = 30), control injection (CI) group (n = 30), and IPFP MSC–derived exosome injection (IMEI) group (n = 30). At 2, 4, and 8 weeks postoperatively, tendon-bone healing and intra-articular graft remodeling were evaluated via biomechanical testing, micro–computed tomography, and histological analysis; macrophage polarization was evaluated using immunohistochemical staining. Results: Biomechanical testing demonstrated a significantly higher failure load and stiffness in the IMEI group than in the SI and CI groups at 4 and 8 weeks postoperatively. Moreover, a thinner graft-to-bone healing interface with more fibrocartilage was observed in the IMEI group at both time points. Micro–computed tomography revealed greater new bone ingrowth in the IMEI group than in the other groups, as demonstrated by smaller mean bone tunnel areas and a larger bone volume/total volume ratio. Additionally, more cellular infiltration was observed in the intra-articular graft in the IMEI group than in the other groups at 4 weeks, followed by more regularly organized fibers with mature collagen at 8 weeks. Notably, similar trends of macrophage polarization were found at both the graft-to-bone interface and the intra-articular graft in the IMEI group, with significantly fewer proinflammatory M1 macrophages and larger numbers of reparative M2 macrophages than in the SI and CI groups. Conclusion: IPFP MSC–derived exosomes accelerated tendon-bone healing and intra-articular graft remodeling after ACLR, which may have resulted from the immunomodulation of macrophage polarization. Clinical Relevance: The IPFP can be easily harvested by most orthopaedic surgeons. Exosomes from IPFP MSCs, constituting a newly emerging cell-free approach, may represent a treatment option for improving tendon-bone healing and intra-articular graft remodeling after ACLR. [ABSTRACT FROM AUTHOR]

Background: Fatty infiltration of the rotator cuff muscles is highly related to poor outcomes after rotator cuff tears. Fat fraction (FF) based on traditional 2–dimensional measurements (2D-FF) from a single sagittal Y-view slice cannot determine intramuscular FF in the rotator cuff muscles; the newly developed 3–dimensional method (3D-FF) is supposed to precede 2D measurements for intramuscular FF evaluation in accuracy and reliability. Purpose: (1) To measure 3D-FF and (2) to compare 3D-FF and 2D-FF in terms of quantitative values and intra- and interobserver agreement. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Six-point Dixon magnetic resonance imaging was performed in patients with full–thickness supraspinatus tears. 2D-FF was calculated on a single sagittal Y-view. Semiautomatic segmentation software (ITK-SNAP) was used to reconstruct 3D volumes of the supraspinatus muscle and fat. 3D-FF was obtained by dividing the fat volume by the total volume of the supraspinatus muscle. A paired t test was used to compare the individual differences between 2D-FF and 3D-FF results. Linear regression and Bland-Altman analyses were performed to determine the agreement between 2D-FF and 3D-FF. Intraclass correlation coefficients (ICCs) were calculated to determine intra- and interobserver agreement. Results: The 3D muscular and fatty models presented an inhomogeneous distribution of intramuscular fat in the supraspinatus, indicating the superiority of 3D-FF over 2D-FF in capturing all muscle morphologic information. 2D-FF was significantly higher than 3D-FF in the supraspinatus with large (19.5% ± 5.9% vs 16.2% ± 3.7%; P =.002) and massive (34.8% ± 13.3% vs 26.2% ± 9.4%; P <.001) rotator cuff tears. 2D-FF overestimated the FF compared with 3D-FF by >50% in 14.7% of all patients and by >15% in 67.6% of patients with large or massive RCTs. The discrepancy between 2D-FF and 3D-FF increased with increasing mean FF. The intra- and interobserver agreement of 3D-FF (ICCs, 0.89-0.99 and 0.89-0.95) was superior to that of 2D-FF (ICCs, 0.71-0.95 and 0.64-0.79). Conclusion: 3D-FF indicated an inhomogeneous distribution of intramuscular fat by capturing all muscle and fat morphologic information. In patients with large and massive rotator cuff tears, 2D-FF of the supraspinatus was significantly higher than 3D-FF. 3D-FF was more reliable than 2D-FF for estimating fatty infiltration in the supraspinatus, with better intra- and interobserver agreement. [ABSTRACT FROM AUTHOR]

Background: Recently, the biceps was rerouted into a newly fabricated bicipital groove for in situ superior capsular reconstruction (SCR), resulting in promising time-zero cadaveric and clinical outcomes. However, no studies have determined the in vivo biomechanical and histological processes after the biceps is transposed to a nonanatomic position. Purpose: To explore the in vivo biomechanical and histological processes of the rerouting biceps tendon to treat chronic irreparable rotator cuff tears (IRCTs) in a rabbit model. Study Design: Controlled laboratory study. Methods: A total of 94 skeletally mature male rabbits were used to create a chronic IRCT model in the supraspinatus tendon. Then, the biceps rerouting procedures were performed in rabbits with chronic IRCT. Eighteen rabbits were sacrificed at 1, 3, 6, 9, and 12 weeks postoperatively for biomechanical testing, micro—computed tomography scanning, and histological analysis. The biomechanical and histological changes of intra- and extra-articular portions of the rerouting biceps were evaluated at each time point, with the contralateral native superior capsule (NSC) and the native biceps (NB) as controls, respectively. The morphology and bone formation of the fabricated bicipital grooves were evaluated, with native grooves as controls. Results: The intra-articular rerouting biceps tendon was progressively remodeled over time, displaying denser fibers and more mature collagen than those of the NSC, with gradual improvements in the tendon-to-bone healing interface from 6 to 12 weeks. Consequently, the failure load and stiffness of the intra-articular rerouting biceps portion increased with time and were significantly higher than those of the NSC from 9 weeks. Similarly, the extra-articular portion of the rerouting biceps progressively healed into a new bicipital groove, as demonstrated by a smaller tendon-to-bone interface from 6 to 12 weeks, resulting in greater failure load and stiffness at 9 and 12 weeks than those of the NB attachment. The newly fabricated bicipital groove showed similar morphology to that of the native groove with sufficient trabecular bone formed underneath. Conclusion: The rerouting biceps could progressively remodel and heal into the newly fabricated bicipital groove over time, resulting in greater biomechanical performances in intra- and extra-articular portions than the NSC and the NB attachment. Clinical Relevance: The biceps rerouting technique may be a feasible procedure to perform in situ SCR to treat IRCT in the future clinical practice; however, more clinical evidence is required. [ABSTRACT FROM AUTHOR]

Background: Medial patellofemoral ligament (MPFL) reconstruction is one of the main treatments for lateral patellar translation. Based on intraoperative true lateral radiographs, the accepted methods for femoral MPFL tunnel location are potentially inaccurate. Direct assessment of anatomic characteristics during surgery through palpation of the anatomic landmarks involving the saddle sulcus might help eliminate tunnel malposition. Hypothesis: The saddle sulcus is a reliable osseous landmark where the MPFL attaches for tunnel placement. Study Design: Descriptive laboratory study. Methods: A total of 9 fresh-frozen unpaired human cadaveric knees were dissected; MPFL insertion point and relative osseous structures were marked. Three-dimensional images and transformed true lateral radiographs were obtained for analysis; 3 previously reported radiographic reference points for MPFL femoral tunnel placement were determined on all images and compared with the anatomic insertion. Results: A saddle sulcus consistently existed where the MPFL was attached, located at 11.7 ± 5.9 mm from the apex of the adductor tubercle (AT) to the medial epicondyle (ME), 62.8% of the average distance between the apexes of the AT and ME, and 5.6 ± 2.8 mm perpendicular-posterior to the border connecting the AT and ME. The reported radiographic reference points were located at average distances of 6.2 ± 3.2 mm (Schöttle method), 5.9 ± 2.3 mm (Redfern method), and 7.3 ± 6.6 mm (Fujino method) from the saddle sulcus center on the true lateral radiographs. Conclusion: The saddle sulcus was a reliable landmark where the MPFL was anatomically attached, located approximately 12 mm from the AT to the ME (approximately 60% along a line from the AT to the ME) and 6 mm perpendicular-posterior to the border connecting the apexes of the AT and ME. Additionally, the saddle sulcus position presented variability on the femoral aspect of different knees. All of the average direct distances from the sulcus to the reference radiographic points exceeded 5 mm, and tunnel localizations on a true lateral radiograph were inaccurate. Clinical Relevance: This study demonstrates the potential precise position of the saddle sulcus, according to the ME and AT, as a reliable anatomic landmark for MPFL femoral tunnel location. Radiographic reference points were not accurate during MPFL reconstruction. Direct palpation of the landmarks might be effective for femoral MPFL tunnel placement. [ABSTRACT FROM AUTHOR]

Background:The common fresh-frozen allografts that are used for anterior cruciate ligament (ACL) reconstructions behave slower during the remodeling process and produce weaker tendon-bone integrations than do autografts. Decellularization of allogenic tendons results in a clean and porous collagen scaffold with low antigenicity and high compatibility, which may be more suitable for ACL reconstructions.Hypothesis:Allograft decellularization will result in a tissue structure with suitable mechanical characteristics for ACL reconstruction, thereby promoting graft remodeling and enhancing tendon-bone healing.Study Design:Controlled laboratory study.Methods:Decellularized allograft tissues were prepared with a pH-modified decellularization process and evaluated for their biocompatibility and biomechanical character in vitro. Eighty New Zealand White rabbits were divided into 2 groups, with 40 in each group, to receive ACL reconstruction with either fresh-frozen (common) allografts or decellularized allografts on both knees. At 2, 4, 8, and 12 weeks postoperatively, the rabbits were euthanized for biomechanical testing, micro–computed tomography analysis, and histologic analysis.Results:The pH-modified decellularized allograft tissues kept excellent biocompatibility and biomechanical character during the in vitro study. Biomechanical testing indicated that the decellularized allograft had significantly higher ultimate load (P = .02) and stiffness (P = .01) levels than the common allograft at 12 weeks, and there was no significant difference between the 2 groups at any other time point. The micro-CT evaluation determined significantly higher bone mineral density (P < .01) in the decellularized allograft group than that in the common allograft group at 12 weeks, but no difference between the 2 groups was observed at any other time point. Regarding bone volume/total volume, there was no difference between the 2 groups at any time point. Fibroblast ingrowths, vascular formation, and connective tissue formation in the tendon-bone interface were better in the decellularized group within 8 weeks. New bone formation was more common in the decellularized allograft group. The collagen birefringence was restored more quickly in the decellularized allograft group than in the common allograft group at all time points.Conclusion:The use of pH-modified decellularized allografts compared with the common allografts resulted in better cellularity, vascularity, collagen matrix remolding, new bone formation around the graft, enhanced tendon-bone healing, and higher ultimate failure load and stiffness of the graft after ACL reconstruction in the rabbit model.Clinical Relevance:The pH-modified decellularized allograft may be a better graft option than the common fresh-frozen allograft for knee ligament reconstructions. [ABSTRACT FROM AUTHOR]

Background:In previous studies, unimodal, small-diameter collagen fibrils have been commonly observed as the final collagen ultrastructure of the implanted grafts used in anterior cruciate ligament (ACL) reconstruction. However, the native ACL and hamstring tendon show bimodal collagen fibril distribution, consisting of both large- and small-diameter collagen fibrils.Hypothesis:Bimodal collagen fibril distribution of the graft is a common phenomenon after ACL reconstruction with hamstring tendon grafts and is time dependent.Study Design:Controlled laboratory study.Methods:A total of 52 patients who underwent double-bundle ACL reconstruction using autogenous hamstring tendons and who also underwent second-look arthroscopic surgery were enrolled. The patients were divided into 2 groups according to the time interval between the 2 operations: the midterm group (27 patients), with a 13- to 30-month time interval between operations, and the long-term group (25 patients) with a 31- to 62-month interval. During the second-look arthroscopic procedures, ACL graft biopsies were performed. Normal ACL tissues were harvested from 9 patients who underwent total knee replacement, and biopsy specimens of the to-be-grafted semitendinosus tendon tissues were also harvested from another 9 patients who underwent ACL reconstruction with hamstring tendons, which were designated as normal controls. Graft vascularity, cellularity, metaplasia, cellular metabolism, and collagen fibril distribution were analyzed.Results:Large-diameter (>100 nm) collagen fibrils were detected in 81.5% of the specimens in the midterm group and in 68.0% of the specimens in the long-term group. A typical bimodal distribution mode was observed in 62.6% of the specimens in the midterm group and in 52.0% of the specimens in the long-term group. There was no significant difference between groups with respect to the presence of large-diameter collagen fibrils, bimodal distribution, graft vascularity, cellularity, metaplasia, or cellular metabolic status.Conclusion:Graft ultrastructural maturation, characterized by large-diameter collagen fibrils and a bimodal collagen fibril distribution, is a common phenomenon and is not time dependent in the midterm to long term.Clinical Relevance:After hamstring tendon ACL reconstruction, the implanted grafts can transform into ACL-like tissue with a similar ultrastructure and metabolism, implying their usefulness as grafts. [ABSTRACT FROM AUTHOR]

Background: The comparative clinical outcome of medial patellofemoral ligament reconstruction (MPFLR) using semitendinosus tendons with and without polyester suture augmentation for recurrent patellar instability is unknown.Hypothesis: Medial patellofemoral ligament reconstruction with polyester suture augmentation will yield better results than MPFLR without augmentation for recurrent patellar instability in adults.Study Design: Randomized controlled trial; Level of evidence, 2.Methods: One hundred patients with recurrent patellar instability receiving MPFLR using semitendinosus tendons were randomly divided into 2 groups either with or without polyester suture augmentation. Tibial tubercle transfer was performed in most cases. Follow-ups were performed at 12, 24, and 60 months postoperatively, and computed tomography (CT) was performed immediately after the operation and at follow-up. The passive patellar glide test was performed before surgery, immediately after MPFLR during the operation, and at each follow-up point. The degree of knee function was evaluated preoperatively and at 2 and 5 years postoperatively using the International Knee Documentation Committee, Lysholm, and Kujala rating scales. Redislocation or multiple episodes of patellar instability were considered failures.Results: Forty-two patients in the augmentation group and 43 patients in the nonaugmentation group were followed for 5 years and received complete serial CT examinations and functional evaluations. The correction of the static patellar position deteriorated over time in the nonaugmentation group but not in the augmentation group. The results of the passive patellar glide test indicated stable patellae in all patients immediately after MPFLR and more stable patellae in the augmentation group at each follow-up point. Functional evaluations at 2 and 5 years revealed statistically significant superior results in the augmentation group. Finally, no patient in the augmentation group and 2 (4.7%) in the nonaugmentation group experienced episodes of redislocation, and 1 patient (2.4%) in the augmentation group and 8 (18.6%) in the nonaugmentation group experienced multiple episodes of patellar instability, resulting in failure rates of 2.4% and 23.3% in the augmentation group and nonaugmentation group, respectively (P = .004).Conclusion: Medial patellofemoral ligament reconstruction with polyester suture augmentation results in better static patellar position, dynamic stability, and functional outcome than without augmentation in the treatment of recurrent patellar dislocation in adults. [ABSTRACT FROM PUBLISHER]

Background: The comparative clinical outcome of medial retinaculum plication (MRP) versus medial patellofemoral ligament reconstruction (MPFLR) for recurrent patellar instability in adults is unknown.Hypothesis: Arthroscopic MRP can yield similar results to MPFLR for recurrent patellar instability in adults.Study Design: Randomized controlled trial; Level of evidence, 2.Methods: One hundred patients with recurrent patellar instability were randomly divided into 2 groups receiving either arthroscopic MRP or MPFLR. Lateral release and anteromedial or distal tibial tubercle transfers were also performed as indicated. Follow-ups were performed at 12, 24, and 60 months postoperatively, and computed tomography (CT) was performed immediately after the operation and at follow-up. The passive patella glide test was performed before surgery and at each follow-up point. The degree of knee function was evaluated preoperatively and at 2 and 5 years postoperatively using the International Knee Documentation Committee (IKDC), Lysholm, and Kujala rating scales. Survival analysis was performed, and redislocation or multiple episodes of patellar instability were considered as indicating failure.Results: Forty-three patients in the MRP group and 45 patients in the MPFLR group were followed for 5 years and received complete evaluations. The correction of the static patellar position deteriorated over time in both groups, but significantly better results were observed for the MPFLR group. The results of the passive patella glide test indicated more stable patellae in the MPFLR group at each follow-up point. Functional evaluations at 2 and 5 years (final Lysholm score, 69.3 ± 6.9 vs 86.9 ± 6.1; Kujala score, 73.8 ± 5.5 vs 87.4 ± 5.7) revealed statistically significant superior results in the MPFLR group. Finally, 4 patients (9.3%) in the MRP group and 1 (2.2%) in the MPFLR group experienced episodes of redislocation, and 7 patients (16.3%) in the MRP group and 3 (6.7%) in the MPFLR group experienced multiple episodes of patellar instability (P = .037). Kaplan-Meier survival analysis and a log-rank test indicated better results and a significantly higher survival rate (P = .006) in the MPFLR group.Conclusion: MPFLR results in better static patellar position and functional outcome than MRP in the treatment of recurrent patellar dislocation in adults. [ABSTRACT FROM PUBLISHER]

Background: Little information is available regarding parameters that would enable a surgeon to predict the size and length of 4-stranded semitendinosus (ST) and 4-stranded gracilis tendon (GT) grafts.Purpose: To evaluate whether certain preoperative anthropometric data enable prediction of the size of 4-stranded ST and GT autograft for anterior cruciate ligament (ACL) reconstruction.Study Design: Cohort study (prevalence); Level of evidence, 2.Methods: This study involved 235 Chinese Han patients who underwent double-bundle ACL reconstruction with 4-stranded autogenous ST and GT grafts. Preoperatively, the authors recorded height, weight, body mass index (BMI), gender, age, and sports activity. During surgery, the usable length of the ST and GT and the diameter of the 4-stranded grafts made of ST and GT were measured. Multiple regression analysis was used to determine relationships between anthropometric measurements and the length and diameter of intraoperatively measured ST and GT grafts.Results: Strongest correlations for ST and GT length and GT graft diameter were height and weight. The strongest correlations for ST graft diameter were gender and weight. Body mass index had only moderate correlations with ST and GT graft size. Self-reported activity level was not correlated. Women had significantly smaller GT and ST graft diameters and shorter tendon lengths than did men. Semitendinosus graft size was significantly larger and longer than was the GT graft (7.4 ± 0.7 mm vs 5.9 ± 0.6 mm and 279.9 ± 20.8 mm vs 251.5 ± 20.8 mm, respectively). Simple regression analysis demonstrated that height, weight, and BMI can be used to predict ST and GT autograft length and diameter.Conclusion: Several preoperative anthropometric measurements showed correlation with the length of the ST and GT and diameter of 4-stranded ST and GT grafts. The current data may provide surgeons with important preoperative information about size of ST and GT grafts and would be useful for patient counseling and alternative graft source planning. [ABSTRACT FROM PUBLISHER]

Background: The shortage of autogenous grafts has often times been a problem in knee ligament reconstruction. There are little data concerning the use of the anterior half of the peroneus longus tendon (AHPLT) as an autograft.Hypothesis: The AHPLT is a suitable graft with respect to its strength, safety, and donor site morbidity.Study Design: Descriptive laboratory study and case series; Level of evidence, 4.Methods: The safety and efficacy of using the AHPLT as an autograft source were evaluated. A cadaveric study was first done to reveal the anatomic profile of the AHPLT, to test its failure load, and to compare it with that of the semitendinosus and gracilis tendons. Then, a cadaveric harvest study was performed to show it was safe and reproducible. The space between the tendon stripper and the peroneal nerve during harvesting of the AHPLT was evaluated. Lastly, a clinical study was performed to evaluate donor site morbidity. The preoperative and postoperative foot and ankle functions of 92 patients who underwent a variety of knee ligament reconstructions with the AHPLT were followed for more than 2 years and were then evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) scale and the Foot and Ankle Disability Index (FADI) to determine the influence of tendon removal on ankle and foot function.Results: The average failure load of the AHPLT was 322.35 ± 63.18 N, accounting for 97.69% ± 19.48% and 147.94% ± 41.30% of the semitendinosus and gracilis tendons, respectively. During tendon harvesting, the distance between the head of the tendon stripper and the branching point of the deep peroneus nerve was 4.6 to 10.4 cm. The clinical study showed that the preoperative and postoperative AOFAS scores were 97.4 ± 2.0 and 97.2 ± 1.6 (P = .85), respectively, while the FADI scores preoperatively and postoperatively were 96.8 ± 2.2 and 96.9 ± 2.5 (P = .91), respectively. No signs of peroneus nerve injury, peroneus longus tendon rupture, or tendinopathy were found.Conclusion: The AHPLT is acceptable for use as an autograft with respect to its strength, safety, and donor site morbidity. [ABSTRACT FROM PUBLISHER]

Background: The clinical outcome of arthroscopic medial retinaculum plication (MRP) compared with vastus medialis plasty (VMP) for recurrent patellar dislocation in adolescents is unknown.Hypothesis: Arthroscopic MRP can yield similar results to open VMP for recurrent patellar dislocation in adolescents.Study Design: Randomized controlled clinical trial; Level of evidence, 2.Methods: Sixty adolescent patients were randomly divided into 2 groups to receive arthroscopic MRP and open VMP respectively. The patients were followed up at 3, 6, 12, and 24 months postoperatively and computed tomography (CT) scans were taken immediately after operation and at 12 and 24 months postoperatively to evaluate the position of the patella. Knee function was evaluated at 24 months postoperatively according to the International Knee Documentation Committee (IKDC), Kujala, Lysholm, and Tegner rating scales. For those who underwent operation more than 3 years previously, an additional review was taken to evaluate the latest patellar stability status.Results: The final follow-up time was 56.8 ± 21.5 months (range, 24-92 months) and 59.1 ± 24.7 months (range, 24-88 months), respectively, in the MRP and VMP groups. The CT examination showed that the correction of the patellar position deteriorated over time in both groups. The final patellar position was significantly better than that before surgery in the VMP group, but not in the MRP group. The VMP group had significantly better clinical results at each follow-up compared with the MRP group. The IKDC, Lysholm, Kujala, and Tegner scores were 62.5 ± 6.2, 70.7 ± 5.1, 76.6 ± 4.8, and 3.9 ± 0.7, respectively, in the MRP group, and 71.8 ± 7.1 (P < .001), 79.4 ± 5.5 (P < .001), 82.9 ± 4.8 (P < .001), and 5.1 ± 1.4 (P < .001), respectively, in the VMP group at the 2-year follow-up. Five patients (17.9%) in the MRP group and 2 patients (7.7%) in the VMP group (P = .267) experienced episodes of redislocation at the final follow-up.Conclusion: Arthroscopic MRP is less reliable for maintaining the corrected position of the patella and for functional recovery compared with VMP for recurrent patellar dislocation in adolescents. [ABSTRACT FROM PUBLISHER]