Periostin regulation and cartilage degradation early after anterior cruciate ligament reconstruction.

OBJECTIVE AND DESIGN: The purpose of this study was to explore pathological processes during the first 4 weeks after anterior cruciate ligament reconstruction (ACLR). SUBJECTS: Sixteen ACL-injured patients (8 females/8 males, mean age = 19.1, mean BMI = 28.6). METHODS: Arthrocentesis was performed 1 and 4 weeks after ACLR. Proteins in the synovial fluid were identified using nanoLC-ESI-MS/MS. Differentially up- or down-regulated proteins were identified and quantified, and a pathway analysis was performed. All identified proteins were mapped into a protein-protein interaction (PPI) network, and networks of PPIs with a combined score > 0.9 were then visualized. RESULTS: Seven pathways were upregulated after ACLR: PI3K-AKT signaling pathway, extracellular matrix (ECM)-receptor interaction, focal adhesion, protein digestion and absorption, ameobiasis, and platelet activation. Network analyses identified 8 proteins that were differentially upregulated with strong PPI interactions (periostin and 7 collagen-related proteins). Increases in periostin moderately correlated with increases in a synovial fluid biomarker of type II cartilage degradation (ρ = 0.51, p = 0.06). CONCLUSION: Pro-inflammatory pathways and periostin were upregulated after ACLR. Periostin demonstrated strong network connections with markers of collagen breakdown, and future work is needed to determine whether periostin may offer a biomarker of early cartilage degradation after ACLR and/or play an active role in early post-traumatic osteoarthritis (PTOA) progression.

From Inflammation to Resolution: Specialized Pro-resolving Mediators in Posttraumatic Osteoarthritis.

PURPOSE OF REVIEW: To provide a comprehensive overview of the inflammatory response following anterior cruciate ligament (ACL) injury and to highlight the relationship between specialized pro-resolving mediators (SPMs) and inflammatory joint conditions, emphasizing the therapeutic potential of modulating the post-injury resolution of inflammation to prevent posttraumatic osteoarthritis (PTOA). RECENT FINDINGS: The inflammatory response triggered after joint injuries such as ACL tear plays a critical role in posttraumatic osteoarthritis development. Inflammation is a necessary process for tissue healing, but unresolved or overactivated inflammation can lead to chronic diseases. SPMs, a family of lipid molecules derived from essential fatty acids, have emerged as active players in the resolution of inflammation and tissue repair. While their role in other inflammatory conditions has been studied, their relationship with PTOA remains underexplored. Proinflammatory mediators contribute to cartilage degradation and PTOA pathogenesis, while anti-inflammatory and pro-resolving mediators may have chondroprotective effects. Therapies aimed at suppressing inflammation in PTOA have limitations, as inflammation is crucial for tissue healing. SPMs offer a pro-resolving response without causing immunosuppression, making them a promising therapeutic option. The known onset date of PTOA makes it amenable to early interventions, and activating pro-resolving pathways may provide new possibilities for preventing PTOA progression. Harnessing the pro-resolving potential of SPMs may hold promise for preventing PTOA and restoring tissue homeostasis and function after joint injuries.

Systematic Review of Clinical Results After Medial Meniscus Allograft Transplantation Reveals Improved Patient Reported Outcomes at Greater Than 5 Years Follow-Up.

PURPOSE: To systematically summarize the medial meniscus allograft transplantation (MAT) reported outcomes and evaluate whether the surgical technique is associated with allograft extrusion and knee function. METHODS: Systematic review was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Inclusion criteria were English-language clinical studies involving arthroscopically assisted medial MAT that reported the surgical technique and the presence of graft extrusion or functional outcomes after surgery. Studies in which outcomes for medial MAT could not be separated from lateral MAT were excluded. Surgical technique, allograft-related characteristics, and clinical outcomes were extracted. RESULTS: Twenty-four studies with 328 medial MAT were included, 58.3% studies qualified as level 4 of evidence, 29.2% as level 3, and 12.5% as level 2. Allograft fixation techniques were bone plug (235/328 [71.6%]), bone bridge/trough (55/328 [16.8%]), and soft-tissue suture fixation only (38/328 [11.6%]). Relative percentage of extrusion after surgery ranged from 24.8% to 53.7%. Major extrusion (>3 mm) ranged from zero to 78%. Overall, functional scores improved after medial MAT. None of surgical techniques were associated with poor functional outcomes or extruded meniscus; however, nonanatomical placement of the anterior and posterior horns appeared to increase meniscus extrusion. CONCLUSION: Medial MAT provides favorable outcomes, with acceptable rates of complication and failure regardless of surgical technique. Although allograft extrusion appears equivalent for both bone plug and soft-tissue fixation techniques, positioning allograft horns at the native meniscal footprint may be critical for preventing extrusion. However, the heterogeneity and low level of evidence of the studies included in this review prevent decisive conclusions regarding optimal MAT fixation techniques, clinical significance of allograft extrusion, or comparative clinical outcomes after medial MAT. LEVEL OF EVIDENCE: Level IV - systematic review of Level II to IV studies.

Increased risk of reoperation and failure to attain clinically relevant improvement following autologous chondrocyte implantation of the knee in female patients and individuals with previous surgeries: a time-to-event analysis based on the German cartilage registry (KnorpelRegister DGOU).

PURPOSE: This study aimed to analyze the risk of reoperation following autologous chondrocyte implantation (ACI) of the knee utilizing third-generation ACI products in a time-to-event analysis and report on the associated patient-reported outcome measures (PROM) in case of reoperation. METHODS: Patients undergoing ACI were included from a longitudinal database. Patient age, sex, body mass index (BMI), number of previous surgeries, lesion localization, lesion size, symptom duration, as well as time and type of reoperation was extracted. A cox proportional-hazards model was applied to investigate the influence of baseline variables on risk of reoperation. Reoperation was defined as any type of subsequent ipsilateral knee surgery, excluding hardware removal. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was utilized to compare PROM between patients with and without reoperation. RESULTS: A total of 2039 patients were included with 1359 (66.7%) having a minimum follow-up of 24 months. There were overall 243 reoperations (prevalence 17.9%). Minor arthroscopic procedures (n = 96, 39.5%) and revision cartilage repair procedures (n = 78, 32.1%) were the most common reoperations. Nineteen patients (0.9%) reported conversion arthroplasty at 17.7 (10.4) months after ACI. Female sex (HR 1.5, 95% CI [1.2, 2.0], p = 0.002) and the presence of 1-2 previous surgeries (HR 1.5, 95% CI [1.1, 2.0], p = 0.010), or more than 2 previous surgeries (HR 1.9, 95% CI [1.2, 2.9], p = 0.004) were significantly associated with increased risk of reoperation following ACI. Significantly less patients surpassed the minimal clinically important difference (MCID) in the reoperation group at 24 months regarding the KOOS subscores pain (OR 1.6, 95% CI [1.1, 2.2]), quality of life (OR 2.2, 95% CI [1.6, 3.2]), symptoms (OR 2.0 [1.4, 2.9]), and sports (OR 2.0 [1.4, 2.8]). CONCLUSION: Female patients and individuals with a history of previous surgeries face an elevated risk of requiring reoperation after undergoing ACI, which is associated with failure to attain clinically relevant improvements. A thorough evaluation of the indications for ACI is paramount, particularly when patients have a history of previous surgeries. LEVEL OF EVIDENCE: Level III.

Treatment of post-meniscectomy knee symptoms with medial meniscus replacement results in greater pain reduction and functional improvement than non-surgical care.

PURPOSE: Partial meniscectomy is a common orthopedic procedure intended to improve knee pain and function in patients with irreparable meniscal tears. However, 6-25% of partial meniscectomy patients experience persistent knee pain after surgery. In this randomized controlled trial (RCT) involving subjects with knee pain following partial meniscectomy, it was hypothesized that treatment with a synthetic medial meniscus replacement (MMR) implant provides significantly greater improvements in knee pain and function compared to non-surgical care alone. METHODS: In this prospective, multicenter RCT, subjects with persistent knee pain following one or more previous partial meniscectomies were randomized to receive either MMR or non-surgical care. This analysis evaluated the 1-year outcomes of this 2-year clinical trial. Patient-reported knee pain, function, and quality of life were measured using nine separate patient-reported outcomes. The primary outcomes were the pain subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS) and the average of all five KOOS subscales (KOOS Overall). Treatment cessation was defined as permanent device removal in the MMR group and any surgical procedure to the index knee in the non-surgical care group. RESULTS: Treated subjects had a median age of 52 years old (range 30-69 years) and one or more previous partial meniscectomies at a median of 34 months (range 5-430 months) before trial entry. Among 127 subjects treated with either MMR (n = 61) or non-surgical care (n = 66), 11 withdrew from the trial or were lost to follow-up (MMR, n = 0; non-surgical care, n = 11). The magnitude of improvement from baseline to 1 year was significantly greater in subjects who received MMR in both primary outcomes of KOOS Pain (P = 0.013) and KOOS Overall (P = 0.027). Treatment cessation was reported in 14.5% of non-surgical care subjects and only 4.9% of MMR subjects (n.s.). CONCLUSION: Treatment with the synthetic MMR implant resulted in significantly greater improvements in knee pain, function, and quality of life at 1 year of follow-up compared to treatment with non-surgical care alone. LEVEL OF EVIDENCE: I.

Imaging of meniscal allograft transplantation: what the radiologist needs to know.

Meniscal allograft transplantation is an emerging surgical option for younger patients with symptomatic meniscal deficiency, which aims to restore anatomic biomechanics and load distribution in the knee joint, and by so doing to potentially delay accelerated osteoarthritis. In this review article, we summarize the structure and biomechanics of the native meniscus, describe indications and procedure technique for meniscal allograft transplantation, and demonstrate the spectrum of expected postoperative imaging and role of imaging to identify potential complications.

Safety and Efficacy of an Amniotic Suspension Allograft Injection Over 12 Months in a Single-Blinded, Randomized Controlled Trial for Symptomatic Osteoarthritis of the Knee.

PURPOSE: The purpose of this study is to determine the efficacy of amniotic suspension allograft (ASA) compared to hyaluronic acid (HA) and saline at up to 12 months of follow-up through the use of patient-reported outcomes, immunoglobulin levels, and anti-human leukocyte antigen (HLA) levels. METHODS: Within this multicenter study, 200 patients were randomized 1:1:1 to a single intra-articular injection of saline, HA, or ASA. Patient-reported outcomes, including Knee Injury and Osteoarthritis Outcome Score (KOOS) and visual analog scale (VAS) score, were collected at multiple time points (baseline, 1 week, 6 weeks, 3 months, 6 months) out to 12 months to assess improvements in pain and function. Radiographs at baseline and 12 months were taken to determine radiographic changes, while blood was collected at baseline, 6 weeks, and 6 months to determine changes in immunoglobulins and anti-HLA levels. Statistical analyses were performed using last observation carried forward and mixed effects model for repeated measures. RESULTS: Treatment with ASA resulted in significant improvements in KOOS and VAS scores that were maintained through 12 months (P < .05). Treatment with ASA resulted in a 63.2% responder rate at 12 months using the Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International simplified definition. There were no significant differences between groups for radiographic measures in the index knee, immunoglobulins, C-reactive protein, or anti-HLA serum levels (P > .05). The number and type of adverse events (AEs) reported for ASA were comparable to the HA injection group, while no treatment-emergent AEs were reported for the saline group. CONCLUSIONS: This randomized controlled trial of ASA vs HA and saline for the treatment of symptomatic knee osteoarthritis demonstrated clinically meaningful improved outcomes with ASA over the controls out to 12 months postinjection. No concerning immunologic or adverse reactions to the ASA injection were identified with regards to severe AEs, immunoglobulin, or anti-HLA levels. LEVEL OF EVIDENCE: Level I, randomized controlled multicenter trial.

Correlations of Single-Leg Performance Tests to Patient-Reported Outcomes After Primary Anterior Cruciate Ligament Reconstruction.

OBJECTIVE: To determine the relationship between patient-reported outcomes (PROs) to the single-leg step-down test (SLSD) and the Y-balance anterior reach (YB-A) 6 months after primary anterior cruciate ligament reconstruction (ACLR). DESIGN: Cross-sectional. SETTING: Laboratory. PARTICIPANTS: Sixty-six patients 6 months after ACLR participated. INTERVENTIONS: Patients performed the SLSD, YB-A, and completed PROs after ACLR. MAIN OUTCOME MEASURES: Patients completed the International Knee Documentation Committee Score (IKDC), the Lysholm Activity Scale, the Tampa Scale of Kinesiophobia (TSK-11), and the Knee Injury and Osteoarthritis Outcome Score (KOOS)-Symptom, -Sport, and -Quality of Life (QOL) subscales. The SLSD requires subjects to complete as many single-leg step-downs as possible in 60 seconds, and the YB-A involves reaching anteriorly on a single limb. Pearson product moment correlations were used to assess relationships between the YB-A and SLSD performance to each PRO. RESULTS: Single-leg step-down test symmetry was significantly correlated with the TSK-11 (r = -0.70), KOOS-Sport (r = 0.40), -Symptom (r = 0.46), and -QOL (r = 0.42). The YB-A symmetry was significantly correlated with the KOOS-Symptom (r = 0.30) and KOOS-Sport (r = 0.30). CONCLUSIONS: Single-leg step-down test performance demonstrated stronger relationships to patient-reported knee function than the YB-A. Furthermore, the SLSD symmetry was strongly correlated with fear of movement. The SLSD provides a robust method for clinicians to assess dynamic knee function and may aid in identifying patients who could benefit from intervention to reduce fear of movement or reinjury.

Cartilage Disease of the Patellofemoral Joint: Realignment, Restoration, Replacement.

Chondral lesions of the patellofemoral joint are common, and when symptomatic they can be difficult to manage. Not only are there various degrees of injury with multiple etiologies, but patellofemoral anatomy is complex and the patient's lower extremity alignment may contribute to the pathology. Treatment depends on the location, size, and depth of the lesion and may require realignment or concomitant stabilizing procedures. Tibial tubercle osteotomy can be performed in isolation or combined with various cartilage-based treatments, including marrow stimulation techniques, autologous chondrocyte implantation, osteochondral autograft, and osteochondral allograft. End-stage lesions, failed primary patellofemoral cartilage restoration with diffuse involvement, or isolated primary patellofemoral arthritis may be amenable to treatment with patellofemoral arthroplasty. Recent investigations in properly indicated patients using advanced techniques have shown that management of patellofemoral cartilage disease is now more effective and predictable than in the past.

Reliability of wearable sensors to assess impact metrics during sport-specific tasks.

There is little information on the reliability of inertial measurement units for capturing impact load metrics during sport-specific movements. The purpose of this study is to determine the reliability of the Blue Trident IMU sensors in measuring impact load, step count and cumulative bone stimulus during a series of soccer-related tasks. Ten healthy recreational soccer players (age: 27.9 ± 2.18; height: 1.77 ± 0.10 m; mass: 79.02 ± 13.07 kg) volunteered for a 3-visit study and performed 4 tasks. Bilateral impact load, total number of steps and cumulative bone stimulus during the tasks were collected. Data were sampled using a dual-g sensor. Intraclass correlation coefficients (ICC3,1) with 95% confidence intervals assessed between-day reliability. Impact load (0.58-0.89) and cumulative bone stimulus (0.90-0.97) had good to excellent reliability across tasks. ICC values for right/left step count were good to excellent during acceleration-deceleration (0.728-0.837), change direction (0.734-0.955) and plant/cut manoeuvres (0.701-0.866) and fair to good during the ball kick (0.588-0.683). This suggests that wearable sensors can reliably measure the cumulative impact load during outdoor functional movements; however, kicking manoeuvres are less reliable. Measuring impact load in the field expands the ability to capture more ecologically valid data.

The Relationship Between Patient Expectations and Functional Outcomes in Patients Undergoing Cartilage Repair of the Knee: A Mixed Methods Study.

CONTEXT: Patient expectations have been shown to be a major predictor of outcomes. Fulfilled expectations have been linked to increased patient satisfaction and rehabilitation adherence. Expectations may be influenced by a variety of factors, including patient characteristics, preoperative function, or disease characteristics. It is currently unknown what factors may influence patient expectations prior to cartilage repair of the knee, and to what degree. Furthermore, understanding the importance and values of those expectations for recovery using mixed methods has not previously been conducted in this patient population. The purpose of this mixed methods study is to examine and explore the relationships between patient expectations and functional outcome in patients undergoing cartilage repair of the knee. DESIGN: A mixed methods design was used. METHODS: Twenty-one patients scheduled to undergo cartilage repair of the knee were included. Participants completed the Hospital for Special Surgery Knee Surgery Expectations Survey and the Knee Injury and Osteoarthritis Outcome Score at their preoperative visit. Knee Injury and Osteoarthritis Outcome Scores were also obtained at 3 and 6 months postsurgery. A selected sample of 6 participants participated in semi-structured interviews 6 months postsurgery. Pearson correlation coefficients were used to determine relationships between expectations and functional outcome. RESULTS: Patients have moderate expectations for recovery, and these expectations were positively associated with preoperative pain, activities of daily living, and quality of life. Expectations also correlated with symptoms 3 months postsurgery, but there were no other significant correlations between preoperative expectations and postoperative function in the short term. Four qualitative themes emerged as participants described how previous recovery experiences shaped their expectations. CONCLUSIONS: Formalized patient and caregiver education, prehabilitation, and the use of psychological skills during rehabilitation may help to manage patient expectations and provide more focused and individualized care, thus improving outcomes.

Relationship Between Pain Catastrophizing and 6-Month Outcomes Following Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Pain catastrophizing predicts poor outcomes following orthopedic procedures for patients with chronic conditions; however, limited research has focused on acute injuries. This study aimed to quantify the progression of Pain Catastrophizing Scale (PCS) scores from injury to 6-months post-anterior cruciate ligament reconstruction (ACLR) and determine if preoperative or 6-month PCS scores were related with self-reported pain or function 6 months post-ACLR. The authors hypothesized PCS scores would minimally fluctuate and would be related with worse outcomes 6-months post-ACLR. METHODS: All 48 participants (27 male/21 female; aged 22.7 [4.6] y, body mass index 24 [3.3]) included in this secondary analysis of a randomized control trial sustained an ACL injury during sports activity. Participants completed the PCS and Pain Visual Analog Scale (VAS) at 5 time points: within 7 days of injury (INITIAL), day of surgery, 2 weeks postoperative (2W), 6 weeks postoperative (6W), and 6 months postoperative (6M). They completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 6M. Wilcoxon signed-rank tests and Spearman rank-order correlations were used for analysis. RESULTS: PCS scores were not fixed (INITIAL: 11.6 [10.8], day of surgery: 2.5 [3.7], 2W: 8.0 [7.8], 6W: 3.7 [6], 6M: 0.8 [2.3]). They fluctuated in response to injury and ACLR similar to Pain VAS scores. Preoperative PCS scores were not related with 6M outcomes; however, 6M PCS scores were significantly related with 6M Pain VAS and KOOS subscales. CONCLUSIONS: PCS scores fluctuated in response to injury and ACLR. Preoperative PCS scores were not related with 6M outcomes; however, 6M PCS scores correlated with pain and function at 6M. High pain catastrophizing appears to be a natural response immediately following acute ACL injury and ACLR, but may not be indicative of a poor postoperative result. PCS scores 6-months following ACLR may provide useful information regarding self-reported pain and function.

The Four Most Common Types of Knee Cartilage Damage Encountered in Practice: How and Why Orthopaedic Surgeons Manage Them.

Cartilage damage of the knee is common and may present in patients as a variety of symptoms. These conditions can be classified based on location, etiology, and/or pathophysiology. A systematic approach to the evaluation and classification of chondral injuries helps improve definitive management. The four most common types of knee cartilage damage are osteochondritis dissecans, incidental chondral defects, patellofemoral defects, and defects encountered after meniscectomy.

Medial Patellofemoral Ligament Reconstruction With Concomitant Tibial Tubercle Transfer: A Systematic Review of Outcomes and Complications.

PURPOSE: To examine the outcomes and complications of medial patellofemoral ligament (MPFL) reconstruction and concomitant tibial tubercle (TT) transfer. METHODS: A systematic review of published literature on MPFL reconstruction and TT transfer was performed using the following databases: PubMed/Medline, CINAHL (Cumulative Index to Nursing and Allied Health Literature), SPORTDiscus, and Cochrane. To be included, studies were required to present outcomes and/or complication data for MPFL reconstruction performed in combination with TT transfer. Each study was assessed for quality and level of evidence. RESULTS: Five studies consisting of 92 knees met the inclusion criteria. Between 57% and 77% of the patients were female patients, and the mean age at surgery was 20.6 years (range, 19 to 31 years). The mean follow-up period was 38 months (range, 23 to 53 months). Postoperative outcome measures including the Lysholm score, Kujala score, International Knee Documentation Committee score, Knee Injury and Osteoarthritis Outcome Score, and visual analog scale score were similar to those previously reported for isolated MPFL reconstruction. Reported complication rates were lower than 15% and included wound infection, hardware irritation, and stiffness. Four studies were graded as Level IV evidence, and 1 study was graded as Level II evidence. Only 1 study scored greater than 50% in the quality analysis. CONCLUSIONS: Results from the analyzed studies indicate that MPFL reconstruction combined with TT transfer is a safe and effective procedure, with a low to moderate risk of complications but overall favorable results. TT transfer is most often performed in conjunction with MPFL reconstruction in the setting of malalignment such as an increased TT-to-trochlear groove distance, and although the surgical indications may differ, the outcomes and risk profiles are similar to those of isolated MPFL reconstruction. With the recognition that these patients are difficult to standardize, additional well-designed studies are needed to further investigate the ideal surgical candidates for MPFL reconstruction with concomitant TT transfer. LEVEL OF EVIDENCE: Level IV, systematic review of Level II and IV studies.

New England journal of medicine article evaluating the usefulness of meniscectomy is flawed.

A controversial article was recently published in the New England Journal of Medicine titled "Arthroscopic Partial Meniscectomy Versus Sham Surgery for a Degenerative Meniscal Tear" by Sihvonen et al. We believe that readers of this article should be careful about making sweeping generalizations regarding the study findings given several methodologic flaws inherent in the population studied. There are significant concerns regarding the generalizability of these data. The actual study sample group is exceedingly small as compared with the normal volume of meniscal surgery the authors are reported to routinely perform. The authors' definition of a sham procedure must be revisited. The authors' final conclusion that "arthroscopic partial meniscectomy is of no value" is simply not what the study found. We share the concerns that several other leading authorities have recently expressed about the societal implications of this work. Arthroscopic partial meniscectomy has revolutionized the way we are able to treat symptomatic meniscal pathology. However, this procedure, like all surgical procedures, must be properly indicated to truly benefit our patients.

Influence of response shift on early patient-reported outcomes following autologous chondrocyte implantation.

PURPOSE: Response shift is the phenomenon by which an individual's standards for evaluation change over time. The purpose of this study was to determine whether patients undergoing autologous chondrocyte implantation (ACI) experience response shift. METHODS: Forty-eight patients undergoing ACI participated. The "then-test" method was used to evaluate response shift in commonly used patient-reported outcome measures (PROMs)-the SF-36 Physical Component Scale (SF-36 PCS), WOMAC, IKDC, and Lysholm. Each PROM was completed pre- and 6 and 12 months post-surgery. At 6 and 12 months, an additional "then" version of each form was also completed. The "then" version was identical to the original except that patients were instructed to assess how they were prior to ACI. Traditional change, response shift adjusted change, and response shift magnitude were calculated at 6 and 12 months. T tests (p < 0.05) were used to compare traditional change to response-shift-adjusted change, and response shift magnitude values to previously established minimal detectable change. RESULTS: There were no differences between traditional change and response-shift-adjusted change for any of the PROMs. The mean response shift magnitude value of the WOMAC at 6 months (15 ± 14, p = 0.047) was greater than the previously established minimal detectable change (10.9). The mean response shift magnitude value for the SF-36 PCS at 12 months (9.4 ± 6.8, p = 0.017) also exceeded the previously established minimal detectable change (6.6). CONCLUSIONS: There was no evidence of a group-level effect for response shift. These results support the validity of pre-test/post-test research designs in evaluating treatment effects. However, there is evidence that response shifts may occur on a patient-by-patient basis, and scores on the WOMAC and SF-36 in particular may be influenced by response shift. LEVEL OF EVIDENCE: II.

Patient-oriented and performance-based outcomes after knee autologous chondrocyte implantation: a timeline for the first year of recovery.

CONTEXT: It is well established that autologous chondrocyte implantation (ACI) can require extended recovery postoperatively; however, little information exists to provide clinicians and patients with a timeline for anticipated function during the first year after ACI. OBJECTIVE: To document the recovery of functional performance of activities of daily living after ACI. PATIENTS: ACI patients (n = 48, 29 male; 35.1 ± 8.0 y). INTERVENTION: All patients completed functional tests (weight-bearing squat, walk-across, sit-to-stand, step-up/over, and forward lunge) using the NeuroCom long force plate (Clackamas, OR) and completed patient-reported outcome measures (International Knee Documentation Committee Subjective Knee Evaluation Form, Lysholm, Western Ontario and McMaster Osteoarthritis Index [WOMAC], and 36-Item Short-Form Health Survey) preoperatively and 3, 6, and 12 mo postoperatively. MAIN OUTCOME MEASURES: A covariance pattern model was used to compare performance and self-reported outcome across time and provide a timeline for functional recovery after ACI. RESULTS: Participants demonstrated significant improvement in walk-across stride length from baseline (42.0% ± 8.9% height) at 6 (46.8% ± 8.1%) and 12 mo (46.6% ± 7.6%). Weight bearing on the involved limb during squatting at 30°, 60°, and 90° was significantly less at 3 mo than presurgery. Step-up/over time was significantly slower at 3 mo (1.67 ± 0.69 s) than at baseline (1.49 ± 0.33 s), 6 mo (1.51 ± 0.36 s), and 12 mo (1.40 ± 0.26 s). Step-up/over lift-up index was increased from baseline (41.0% ± 11.3% body weight [BW]) at 3 (45.0% ± 11.7% BW), 6 (47.0% ± 11.3% BW), and 12 mo (47.3% ± 11.6% BW). Forward-lunge time was decreased at 3 mo (1.51 ± 0.44 s) compared with baseline (1.39 ± 0.43 s), 6 mo (1.32 ± 0.05 s), and 12 mo (1.27 ± 0.06). Similarly, forward-lunge impact force was decreased at 3 mo (22.2% ± 1.4% BW) compared with baseline (25.4% ± 1.5% BW). The WOMAC demonstrated significant improvements at 3 mo. All patient-reported outcomes were improved from baseline at 6 and 12 mo postsurgery. CONCLUSIONS: Patients' perceptions of improvements may outpace physical changes in function. Decreased function for at least the first 3 mo after ACI should be anticipated, and improvement in performance of tasks requiring weight-bearing knee flexion, such as squatting, going down stairs, or lunging, may not occur for a year or more after surgery.

Biologic Impact of Anterior Cruciate Ligament Injury and Reconstruction.

Surgical intervention after anterior cruciate ligament (ACL) tears is typically required because of the limited healing capacity of the ACL. However, mechanical factors and the inflammatory response triggered by the injury and surgery can impact patient outcomes. This review explores key aspects of ACL injury and reconstruction biology, including the inflammatory response, limited spontaneous healing, secondary inflammation after reconstruction, and graft healing processes. Understanding these biologic mechanisms is crucial for developing new treatment strategies and enhancing patient well-being. By shedding light on these aspects, clinicians and researchers can work toward improving quality of life for individuals affected by ACL tears.

Identifying Anterior Cruciate Ligament Injuries Through Automated Video Analysis of In-Game Motion Patterns.

Background: Failure to diagnose anterior cruciate ligament (ACL) injury during a game can delay adequate treatment and increase the risk of further injuries. Artificial intelligence (AI) has the potential to be an accurate, cost-efficient, and readily available diagnostic tool for ACL injury in in-game situations. Purpose: To develop an automated video analysis system that uses AI to identify biomechanical patterns associated with ACL injury and to evaluate whether the system can enhance the ability of orthopaedic and sports medicine specialists to identify ACL injuries on video. Study Design: Descriptive laboratory study. Methods: A total of 91 ACL injury and 38 control movement scenes from online available match recordings were analyzed. The videos were processed to identify and track athletes and to estimate their 3-dimensional (3D) poses. Geometric features, including knee flexion, knee and hip abduction, and foot and hip rotation, were extracted from the athletes' 3D poses. A recurrent neural network algorithm was trained to classify ACL injury, using these engineered features as its input. Analysis by 2 orthopaedic surgeons examined whether providing clinical experts with the reconstructed 3D poses and their derived signals could increase their diagnostic accuracy. Results: All AI models performed significantly better than chance. The best model, which used the long short-term memory network with engineered features, demonstrated decision interpretability and good performance (F1 score = 0.63 ± 0.01, area under the receiver operating characteristic curve = 0.88 ± 0.01). The analysis by the 2 orthopaedic surgeons demonstrated improved diagnostic accuracy for ACL injury recognition when provided with system data, resulting in a 0.08 increase in combined F1 scores. Conclusion: Our approach successfully reconstructed the 3D motion of athletes from a single-camera view and derived geometry-based biomechanical features from pose sequences. Our trained AI model was able to automatically detect ACL injuries with relatively good performance and prelabel and highlight regions of interest in video footage. Clinical Relevance: This study demonstrated the feasibility of using AI to automatically evaluate in-game video footage and identify dangerous motion patterns. Further research can explore the full potential of the biomechanical markers and use of the system by nonspecialists, potentially diminishing the rate of missed diagnosis and the detrimental outcomes that follow.

Hyperbaric oxygen therapy enhances graft healing and mechanical properties after anterior cruciate ligament reconstruction: An experimental study in rabbits.

Hyperbaric oxygen therapy (HBOT) has proven successful in wound healing. However, its potential effects on anterior cruciate ligament (ACL) injuries remain uncertain. This study aimed to investigate the impact of HBOT on graft healing following ACL reconstruction in rabbits. Male New Zealand rabbits underwent ACL reconstruction and were randomly divided into two groups: the HBOT group and the ambient air group. The HBOT group received 100% oxygen at 2.5 atmospheres absolute for 2 h daily for 5 consecutive days, starting from the first day after surgery. The ambient air group was maintained in normal room air throughout the entire period. After 12 weeks following the surgery, animals were euthanized, and their knees were harvested for analysis. The HBOT group demonstrated superior graft maturation and integration in comparison to the ambient air group, as evidenced by lower graft signal intensity on magnetic resonance imaging, decreased femoral and tibial tunnel size, and higher bone mineral density values on high-resolution peripheral quantitative computed tomography scans. Additionally, biomechanical testing indicated that the HBOT group had greater load to failure and stiffness values than the ambient air group. In conclusion, the adjuvant use of HBOT improved ACL graft maturation and integration, reduced tunnel widening, and enhanced the biomechanical properties of the graft. These results may provide important insights into the potential clinical application of HBOT as a therapeutic intervention to enhance graft healing after ACL reconstruction, paving the way for further research in this area.