Intra-articular Injection of Autologous Adipose-Derived Stem Cells or Stromal Vascular Fractions: Are They Effective for Patients With Knee Osteoarthritis? A Systematic Review With Meta-analysis of Randomized Controlled Trials

Background: Intra-articular injection of adipose-derived stem cells, which are divided into adipose-derived mesenchymal stem cells (ASCs) and adipose-derived stromal vascular fractions (ADSVFs), has been reported to be a viable treatment modality for knee osteoarthritis (OA); however, its efficacy remains limited. Purpose: This study aimed to provide comprehensive information about the efficacy and safety of intra-articular injections of autologous ASCs and ADSVFs without adjuvant treatment in patients with knee OA. Study Design: Meta-analysis; Level of evidence, 1. Methods: A systematic search of the MEDLINE, Embase, Web of Science, and Cochrane Library databases was performed to identify randomized controlled trials (RCTs) that evaluated the efficacy and safety of intra-articular injections of autologous ASCs or ADSVFs without adjuvant treatments compared with placebo or hyaluronic acid in patients with knee OA. Clinically, the 100-mm visual analog scale for pain relief and the Western Ontario and McMaster Universities Osteoarthritis Index for functional improvement were implemented. Radiologically, cartilage status was assessed using magnetic resonance imaging (MRI). Procedure-related knee pain, swelling, and adverse events (AEs) were evaluated for safety. Additionally, we performed subgroup analyses comparing ASCs versus ADSVFs. Methodological quality was assessed using the modified Coleman Methodology Score (mCMS). Results: A total of 5 RCTs were included in this study. Based on the meta-analysis, ASCs or ADSVFs showed significantly better pain relief at 6 months ( Z = 7.62; P < .0001) and 12 months ( Z = 7.21; P < .0001) and functional improvement at 6 months ( Z = 4.13; P < .0001) and 12 months ( Z = 3.79; P = .0002), without a difference in procedure-related knee pain or swelling compared with controls. Although a meta-analysis with regard to cartilage improvements was not performed owing to heterogeneous MRI assessment, 3 studies reported significantly improved cartilage status after the injection. No serious AEs associated with ASCs or ADSVFs were reported. Subgroup analyses showed similar efficacy between ASC and ADSVF treatments. The median mCMS was 70 (range, 55-75). Conclusion: For patients with knee OA, intra-articular injection of autologous ASCs or ADSVFs without adjuvant treatment showed remarkable clinical efficacy and safety at short-term follow-up. Some degree of efficacy has been shown for cartilage regeneration in knee OA, although the evidence remains limited. Further RCTs that directly compare ASCs and ADSVFs are needed.

Outcomes of Arthroscopic Decompression of the Anterior Inferior Iliac Spine: A Systematic Review and Meta-analysis

Background: Anterior inferior iliac spine (AIIS) impingement has been increasingly recognized as a source of extra-articular impingement and hip pain. However, no aggregate data analysis of patient outcomes after AIIS decompression has been performed. Purpose: To evaluate outcomes after arthroscopic AIIS decompression. Study Design: Meta-analysis; Level of evidence, 4. Methods: A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were queried for all English-language studies reporting outcomes of arthroscopic AIIS decompression performed in isolation or in conjunction with hip impingement correction surgery. After screening, 10 articles were included. The indications for AIIS decompression were recorded, and weighted mean improvements in patient-reported outcome (PRO) scores, complication rates, and revision rates were calculated. Results: A total of 547 patients (311 women; 57%) were identified, with a total of 620 operative hips. The mean age was 28.42 ± 5.6 years, and the mean follow-up was 25.22 ± 11.1 months. A total of 529 hips (85%) underwent AIIS decompression, 530 hips (85%) underwent femoral osteochondroplasty, and 458 hips (74%) underwent labral repair. Of the patients, 13% underwent bilateral AIIS decompression. The mean modified Harris Hip Score improved from 61.3 ± 6.9 to 88.7 ± 4.7 postoperatively (change, 27.4 ± 5.7 points; P < .001), the Hip Outcome Score–Activities of Daily Living improved from 67.2 ± 10.6 to 91.1 ± 3.2 postoperatively (change, 24.0 ± 8.0 points; P = .001), and the Hip Outcome Score–Sports Specific Subscale improved from 36.8 ± 19.2 to 82.8 ± 3.8 postoperatively (change, 46.0 ± 18.2 points; P = .002). The pooled risk of postoperative complications was 1.1% (95% CI, 0.1%-2.1%), and the pooled risk of needing revision surgery was 1.0% (95% CI, 0.1%-2.0%). No complication was directly attributed to the AIIS decompression portion of the procedure. Conclusion: PROs improved significantly after hip arthroscopy with AIIS decompression, with a low risk of postoperative complications and subsequent revision surgeries. Failure to identify extra-articular sources of hip pain in outcomes of femoroacetabular impingement syndrome, including from the AIIS, could lead to poorer outcomes and future revision surgery.

Individual and Combined Anatomic Risk Factors for the Development of an Anterior Cruciate Ligament Rupture in Men: A Multiple Factor Analysis Case-Control Study

Background: No comparative studies have evaluated anatomic risk factors in a large cohort including both patients with anterior cruciate ligament (ACL) ruptures and healthy participants. Purpose: To determine which anatomic parameters are independently associated with an ACL rupture and the diagnostic values of the individual and combined anatomic parameters. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 352 male patients who underwent arthroscopic ACL reconstruction because of a primary ACL rupture and 350 age-, sex-, body mass index–, and side dominance–matched healthy participants were included. Measurements of 32 previously determined parameters and 7 calculations were performed. Between-group differences were calculated. Univariate and multivariate logistic regression models and receiver operating characteristic curve analysis were conducted for the individual and combined independently associated factors. Results: The mean age and body mass index of all participants were 29.9 ± 7.7 years and 27.2 ± 3.1, respectively. There were significant differences between the groups regarding the notch width (NW), notch shape index, anterior tibial slope, notch width index, NW–eminence width (NW:EW) ratio, notch height, axial lateral wall angle, medial intercondylar ridge thickness, alpha angle, medial tibial depth (MTD), lateral tibial slope (LTS), coronal tibial plateau width, eminence width index, tibial proximal anteroposterior distance (TPAP), lateral condylar anteroposterior distance (LCAP)/TPAP, ACL cross-sectional area, ACL volume, medial and lateral meniscal cartilage height, medial and lateral meniscal cartilage angle (MCA), and medial and lateral meniscal cartilage bone height. The NW:EW ratio (odds ratio [OR], 4.419; P = .017), MTD (OR, 8.617; P = .001), LTS (OR, 2.254; P = .011), LCAP/TPAP (OR, 2.782; P = .037), and medial MCA (OR, 1.318; P = .010) were independently associated with the development of an ACL rupture. Combining the independently associated factors revealed a sensitivity of 93% and a specificity of 94% (area under the curve, 0.968). Conclusion: Patients with ACL ruptures could be distinguished from uninjured controls with high sensitivity and specificity via the combined use of the NW:EW ratio, MTD, LTS, LCAP/TPAP, and medial MCA. In clinical practice, these findings may contribute to the development of preventive strategies for ACL ruptures.

Outcomes of Arthroscopic Latarjet Procedure for Anterior Glenohumeral Instability in Patients With Epilepsy: A Case-Control Study

Background: Unacceptably high rates of redislocation, reoperation, osteoarthritis, and coracoid nonunion have been reported in patients with a seizure disorder after surgery for shoulder instabilitiy. Purpose: To evaluate the objective and subjective functional and radiologic results of the arthroscopic Latarjet procedure for anterior shoulder instability in patients with epilepsy and compare them with the results of patients without epilepsy. Study design: Cohort study; Level of evidence, 3. Methods: A retrospective and comparative case-control analysis of patients operated for shoulder instability with arthroscopic Latarjet was conducted. Nineteen patients (21 unstable shoulders) with a seizure disorder (epilepsy group) were matched with 21 patients without a history of seizure (control group). Demographics, surgical indications, and imaging data were collected. Clinical outcomes at a minimum 2 years of follow-up (range, 2-9 years) postoperatively included Rowe score, Western Ontario Shoulder Instability Index (WOSI), Constant-Murley Shoulder Outcome (CMSO) score, and Single Assessment Numeric Evaluation (SANE). The incidence of complications, recurrent instability, redislocation, revision surgery, repeated seizure(s), and presence of osteoarthritis, coracoid nonunion, and osteolysis were also examined. Results: After a mean follow-up of 4.5 years, no significant differences in functional results were found between patients with and without epilepsy on the average Rowe ( P = .917), WOSI ( P = .621), CMSO ( P = .600), and SANE ( P = .859) scores. A total of 5 patients (7 shoulders) continued to have seizures postoperatively, but no seizure-related glenohumeral instability was documented. One dislocation and 1 subluxation were documented while participating in sports in each study group, comprising a recurrence rate of 9.5%, but no significant differences were found at comparison ( P = .605). A bone defect did not influence the results, as no significant difference was found between the 2 groups. Osteoarthritic changes of the glenohumeral joint were observed in 5 shoulders (23.8%) in the epilepsy group and in 3 (14.3%) in the control group ( P = .451). No case of coracoid nonunion or osteolysis was recorded. There was no statistically significant difference in postoperative athletic activity ( P = .660). However, patients with epilepsy had significantly lower pre- and postoperative sports participation ( P < .001). Conclusion: Arthroscopic Latarjet stabilization can lead to improved functional and subjective outcomes and should be considered in patients with epilepsy with recurrent anterior glenohumeral instability. These results can be achieved regardless of the presence of bone defect and the postoperative control of seizures and are similar to those in patients without epilepsy.

Rate and Timing of Return to Golf After Hip, Knee, or Shoulder Arthroplasty: A Systematic Review and Meta-analysis

Background: The physical and mental health benefits of golf are well recognized, and as a moderate-intensity activity, it is an ideal sport for patients after joint arthroplasty. Purpose: To assess the rate and timing of returning to golf and the factors associated with these after hip, knee, or shoulder arthroplasty. Study Design: Meta-analysis; Level of evidence, 4. Methods: A search of PubMed and Medline was performed in March 2021 in line with the 2009 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Search terms included sport, golf, and arthroplasty. The criterion for inclusion was any published research article studying return to golf after arthroplasty. Random-effects modeling was used to measure rates of returning to golf for each type of arthroplasty. Results: A total of 23 studies were included for review. All studies were retrospective in their methodology. The mean age of patients was 66.8 years (SD, 3.37). Four studies reported on hip arthroplasty, 6 on knee arthroplasty, and 13 on shoulder arthroplasty. Among 13 studies, the mean rate of returning to golf was 80% (95% CI, 70%-89.9%). Hip, knee, and shoulder arthroplasty had mean return rates of 90% (95% CI, 82%-98%), 70% (95% CI, 39%-100%), and 80% (95% CI, 68%-92%), respectively. Among 9 studies, the mean time to return to golf was 4.4 months (95% CI, 3.2-6). Change in handicap was reported in 8 studies (35%) with a mean change of −0.1 (95% CI, –2.4 to +2.2). There were no studies presenting factors associated with return to golf. Conclusion: This is the first meta-analysis of returning to golf after joint arthroplasty. The study reports a high rate of returning to golf, which was greatest after hip arthroplasty. However, the study highlights the paucity of prospective data on demographic, surgical, and golf-specific outcomes after arthroplasty. Future prospective studies are required to eliminate response bias and accurately capture golf and patient-specific outcomes.

The Contribution of Posterior Capsule Hypertrophy to Soft Tissue Glenohumeral Internal Rotation Deficit in Healthy Pitchers

Background: The relationship between posterior capsule adaptations and soft tissue glenohumeral internal rotation deficit (GIRD) in healthy pitchers remains unclear. Purpose/Hypothesis: This study aimed to identify if posterior capsule thickness (PCT) was associated with soft tissue GIRD in healthy pitchers. We hypothesized that there would be a positive relationship between soft tissue GIRD and PCT in the dominant arm, no relationship between soft tissue GIRD and PCT in the nondominant arm, and a strong positive relationship between soft tissue GIRD and the bilateral difference in PCT (posterior capsule hypertrophy [PCH]). Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 45 healthy collegiate and professional pitchers were included. Glenohumeral internal rotation and external rotation range of motion, humeral retroversion, and PCT were measured bilaterally. PCT was determined for unilateral posterior capsule measurements, and PCH of the throwing shoulder was calculated as the bilateral difference in PCT. Soft tissue GIRD was calculated as the sum of clinical GIRD and the bilateral difference in humeral retroversion. Pearson correlation coefficients were determined to evaluate the relationships between dominant arm PCT, nondominant arm PCT, and PCH and soft tissue GIRD. Results: Pearson correlations showed that both dominant arm PCT ( R = −0.13; P = .378) and nondominant arm PCT ( R = 0.21; P = .165) were not related to soft tissue GIRD. However, Pearson correlations did show that the amount of PCH was moderately related to soft tissue GIRD ( R = 0.40; P = .007). Therefore, as the posterior capsule hypertrophied, soft tissue GIRD moderately increased. Conclusion: Increased PCH was associated with an increase in soft tissue GIRD in healthy pitchers. If PCT measurements are feasible, clinicians should consider performing bilateral ultrasound assessments to isolate posterior capsule adaptations (ie, PCH). This will allow clinicians to identify pitchers with potentially maladaptive structural adaptations and optimize management strategies throughout the season to counteract them.

The Biomechanical and Histological Processes of Rerouting Biceps to Treat Chronic Irreparable Rotator Cuff Tears in a Rabbit Model

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.

Association Between Preoperative Patient Factors and Clinically Meaningful Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Machine Learning Analysis

Background: The International Hip Outcome Tool 12-Item Questionnaire (IHOT-12) has been proposed as a more appropriate outcome assessment for hip arthroscopy populations. The extent to which preoperative patient factors predict achieving clinically meaningful outcomes among patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) remains poorly understood. Purpose: To determine the predictive relationship of preoperative imaging, patient-reported outcome measures, and patient demographics with achievement of the minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), and substantial clinical benefit (SCB) for the IHOT-12 at a minimum of 2 years postoperatively. Study Design: Case-control study; Level of evidence, 3. Methods: Data were analyzed for consecutive patients who underwent hip arthroscopy for FAIS between 2012 and 2018 and completed the IHOT-12 preoperatively and at a minimum of 2 years postoperatively. Fifteen novel machine learning algorithms were developed using 47 potential demographic, clinical, and radiographic predictors. Model performance was evaluated with discrimination, calibration, decision-curve analysis and the brier score. Results: A total of 859 patients were identified, with 685 (79.7%) achieving the MCID, 535 (62.3%) achieving the PASS, and 498 (58.0%) achieving the SCB. For predicting the MCID, discrimination for the best-performing models ranged from fair to excellent (area under the curve [AUC], 0.69-0.89), although calibration was excellent (calibration intercept and slopes: –0.06 to 0.02 and 0.24 to 0.85, respectively). For predicting the PASS, discrimination for the best-performing models ranged from fair to excellent (AUC, 0.63-0.81), with excellent calibration (calibration intercept and slopes: 0.03-0.18 and 0.52-0.90, respectively). For predicting the SCB, discrimination for the best-performing models ranged from fair to good (AUC, 0.61-0.77), with excellent calibration (calibration intercept and slopes: –0.08 to 0.00 and 0.56 to 1.02, respectively). Thematic predictors for failing to achieve the MCID, PASS, and SCB were presence of back pain, anxiety/depression, chronic symptom duration, preoperative hip injections, and increasing body mass index (BMI). Specifically, thresholds associated with lower likelihood to achieve a clinically meaningful outcome were preoperative Hip Outcome Score–Activities of Daily Living <55, preoperative Hip Outcome Score–Sports Subscale >55.6, preoperative IHOT-12 score ≥48.5, preoperative modified Harris Hip Score ≤51.7, age >41 years, BMI ≥27, and preoperative α angle >76.6°. Conclusion: We developed novel machine learning algorithms that leveraged preoperative demographic, clinical, and imaging-based features to reliably predict clinically meaningful improvement after hip arthroscopy for FAIS. Despite consistent improvements after hip arthroscopy, meaningful improvements are negatively influenced by greater BMI, back pain, chronic symptom duration, preoperative mental health, and use of hip corticosteroid injections.

Comparing Patient-Reported Outcomes From Sham and Saline-Based Placebo Injections for Knee Osteoarthritis: Data From a Randomized Clinical Trial of Lorecivivint

Background: Durable, meaningful symptom responses to intra-articular saline placebo injections are observed in knee osteoarthritis (OA) trials, but it is unclear if these are due to physiological effects. Purpose: To perform a prospective comparison of patient-reported outcome responses among participants with knee OA who underwent intra-articular injection of saline-based placebo or sham (dry needle). Study Design: Randomized controlled trial; Level of evidence, 2. Methods: From a 24-week randomized double-blind trial, participants with moderate to severe knee OA received 2-mL intra-articular injections of saline-based placebo (PBO; 99.45% PBS) or sham (dry needle) to the target knee. Least squares mean differences of changes from baseline to week 24 were compared between the PBO and sham groups for the following: pain Numeric Rating Scale; Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness, and function; and patient global assessment. Bang Blinding Index was used to evaluate all-group blinding on day 1 and week 24. Results: In total, 116 and 117 participants were randomized to the PBO and sham groups, respectively. Within the full trial population, the mean ± SD age and body mass index were 59.0 ± 8.5 years and 28.97 ± 4.01, respectively. An overall 406 (58.4%) were female, and 394 (57.3%) had Kellgren-Lawrence grade 3 target knee OA. The PBO and sham groups demonstrated clinically meaningful improvements (≥10%) from baseline in all patient-reported outcomes at all time points (ie, weeks 4-24). Mean differences (95% CI) at week 24 between the PBO and sham groups were as follows: pain Numeric Rating Scale, –0.10 (–0.79 to 0.59; P = .78); WOMAC pain, –2.89 (–9.70 to 3.92; P = .40); WOMAC stiffness, –2.37 (–9.37 to 4.63; P = .51); and WOMAC function, –1.39 (–8.06 to 5.29; P = .68). Bang Blinding Index indicated that blinding was maintained. Conclusion: PBO and sham groups demonstrated equivalent patient-reported outcomes at all time points through week 24, suggesting that responses attributed to saline were contextual (ie, to the procedure) and not physiological. Registration: NCT03122860 (ClinicalTrials.gov identifier).

Pitching Mechanics and the Relationship to Accuracy in Professional Baseball Pitchers

Background: Biomechanical predictors of pitching accuracy are underevaluated in baseball research. It is unclear how pitchers with higher accuracy differ in terms of kinematics and upper extremity kinetics. Purpose: To differentiate high- and low-accuracy professional pitchers by full-body kinematic and upper extremity kinetic parameters. Study Design: Descriptive laboratory study. Methods: In total, 121 professional baseball pitchers threw 8 to 12 fastballs while assessed with motion-capture technology (480 Hz). Pitchers were divided into high-accuracy (n = 33), moderate-accuracy (n = 52), and low-accuracy (n = 36) groups based on the absolute center deviation of each pitcher’s average pitch to the center of the pitching chart by greater or less than 0.5 SD from the mean, respectively. The 95% confidence ellipses with comparisons of major and minor radii and pitching probability density grids were constructed. Analysis of variance was used to compare kinematic and kinetic values between groups. Results: The absolute center deviation (14.5% ± 6.7% vs 33.5% ± 3.7% grid width; P < .001) was significantly lower in the high-accuracy compared with the low-accuracy group, with no significant difference in ball velocity (38.0 ± 1.7 vs 38.5 ± 2.0 m/s; P = .222). Lead knee flexion at ball release (30.6°± 17.8° vs 40.1°± 16.3°; P = .023) was significantly less for the high-accuracy pitchers. Peak normalized shoulder internal rotation torque (5.5% ± 1.0% vs 4.9% ± 0.7% body weight [BW] × body height [BH]; P = .008), normalized elbow varus torque (5.4% ± 1.0% vs 4.8% ± 0.7% BW × BH; P = .008), and normalized elbow medial force (42.9% ± 7.3% vs 38.6% ± 6.2% BW; P = .024) were significantly greater for the low-accuracy group compared with the high-accuracy group. Conclusion: Professional pitchers with increased accuracy experienced decreased throwing arm kinetics. These pitchers had increased lead knee extension at later stages of the pitch, potentially providing more stable engagement with the ground and transference of kinetic energy to the upper extremities. Professional pitchers can consider increasing lead knee extension at the final stages of the pitch to improve the accuracy of their throws and mitigate elbow varus torque. Clinical Relevance: Increased elbow varus torque, shoulder internal rotation torque, and elbow medial force in less accurate pitchers may contribute to increased injury risk in this group.