Faculty Bibliography

BACKGROUND:Anterior cruciate ligament (ACL) rupture frequently occurs alongside meniscal injury, together altering the intra-articular environment. While ACL injury triggers an inflammatory cascade within synovial fluid, meniscal injury may intensify these responses, contributing to joint degeneration. However, little is known about how combined ACL and meniscal injuries shape the synovial inflammatory milieu or whether these profiles influence long-term outcomes. PURPOSE/HYPOTHESIS/OBJECTIVE:The purpose was to characterize synovial fluid inflammatory phenotypes at the time of ACL reconstruction with concomitant meniscal injury and assess their association with patient-reported outcome measures (PROMs) and clinically meaningful improvement. It was hypothesized that (1) distinct inflammatory phenotypes would exist, (2) these phenotypes would correlate with symptom severity and recovery, and (3) individual biomarkers' effects on outcomes would vary by phenotype. STUDY DESIGN/METHODS:Cohort study; Level of evidence, 3. METHODS:-means clustering identified high- and low-inflammation phenotypes. PROMs were collected preoperatively on the day of surgery (baseline) and at long-term follow-up. Linear regression assessed biomarker associations with PROMs, with interaction models evaluating effect modification by inflammation phenotype. Minimal clinically important difference (MCID) achievement thresholds were calculated using a distribution-based approach (0.5 × baseline SD) and compared between clusters. RESULTS:< .05). CONCLUSION/CONCLUSIONS:Synovial fluid biomarker profiles at the time of ACL reconstruction with concomitant meniscal injury identified distinct inflammatory phenotypes associated with baseline symptom severity and differential patterns of clinical improvement. Although long-term PROMs were similar between groups, phenotype-dependent biomarker associations, particularly involving MCP-1, suggest that the biological context of recovery differs across inflammatory profiles.

BACKGROUND:Smoking has been linked to alterations in cellular inflammatory pathways and adverse outcomes in orthopaedic procedures. It is unclear how patient smoking affects the intra-articular microenvironment in the setting of symptomatic meniscal tears. PURPOSE/OBJECTIVE:To investigate the association between tobacco use and variation in cytokine concentrations in knee synovial fluid in patients undergoing arthroscopic knee surgery for symptomatic meniscal injury. STUDY DESIGN/METHODS:Cohort study; Level of evidence, 3Methods:Patients who underwent knee arthroscopy for meniscal injury were prospectively enrolled between July 2011 and June 2019. Synovial fluid was aspirated and the concentrations of 10 biomarkers were measured by immunoassay. Smoking status, pack-years, and time since smoking cessation were collected. Log-normalized biomarker concentrations and smoking status were analyzed using analysis of variance (ANOVA) and linear regression. RESULTS:= .0084). CONCLUSION/CONCLUSIONS:Smoking status was found to be significantly associated with alterations in synovial fluid biomarker profiles in patients undergoing arthroscopic knee surgery for meniscal injury. RANTES was negatively associated with pack-years in current smokers, and IL-6 was positively associated with time since smoking cessation in former smokers. These findings suggest that smoking may have lasting effects on joint inflammation after injury, and that biomarker profiles can provide insight into local tissue responses influenced by smoking history.

Osteotomies around the knee-including distal femoral osteotomies, high tibial osteotomies, and tibial tubercle osteotomies-are technically demanding procedures that are generally safe, with relatively low overall complication rates. However, complications do occur and can pose significant challenges, with substantial implications for patient outcomes. Awareness of potential complications and meticulous surgical technique are, therefore, essential to minimizing risk. This review highlights the most clinically relevant complications unique to knee osteotomies. These include vascular injury, hinge and shingle fractures, delayed union or nonunion, femur and tibia fractures, and infection. For each complication, contributing patient and surgical factors are examined, along with an emphasis on strategies for prevention and proposed treatment management algorithms. By combining preventive strategies with structured management guidance, this review aims to serve as a practical reference for optimizing outcomes and reducing the morbidity associated with knee osteotomies.

PURPOSE/OBJECTIVE:Evaluate the association between posterior tibial slope and survivorship following meniscal allograft transplantation and to determine whether a slope threshold is associated with increased risk of graft failure at short-term follow-up. METHODS:A retrospective cohort study was performed of patients who underwent meniscal allograft transplantation from 2011 to 2024 with postoperative lateral radiographs and a minimum 1-year follow-up. Posterior tibial slope was measured using the circle-of-best-fit method. Graft failure was defined as revision surgery, conversion to arthroplasty and meniscal repair and/or meniscectomy of the allograft. Multivariable logistic regression and Cox proportional hazards modelling were used to evaluate the association between slope and failure. Receiver operating characteristic analysis with Youden's index was used to identify an optimal posterior tibial slope threshold, and Kaplan-Meier analysis assessed graft survivorship. RESULTS:Eighty-three meniscal allograft transplantations were included (age 30.7 ± 8.6 years, 55.4% male) with a mean follow-up of 4.4 ± 3.1 years. Twenty-four clinical graft failures (28.9%) occurred at a mean time of 2.3 ± 1.9 years postoperatively. Mean posterior tibial slope was 11.3° ± 3.0° and was not significantly associated with failure when analyzed as a continuous variable (OR 1.1, 95% CI 1.0-1.4, p = 0.174). Receiver operating characteristic analysis identified a threshold of 11.9°, above which survivorship was reduced. Kaplan-Meier analysis demonstrated decreased survival for slope ≥11.9° (log-rank p < 0.001). Compartment-specific analyses demonstrated similar patterns. CONCLUSIONS:Although posterior tibial slope was not independently associated with graft failure when modelled continuously, a threshold of approximately 11.9° was associated with reduced meniscal allograft transplantation survivorship. These findings suggest a potential threshold-dependent relationship between sagittal alignment and graft survival. LEVEL OF EVIDENCE/METHODS:Level III.

PURPOSE/OBJECTIVE:Although bone-patellar tendon-bone autograft is widely used for anterior cruciate ligament reconstruction, it is often associated with anterior knee pain resulting from the residual patellar bone defect. Various materials have been proposed to fill this void, yet no consensus exists regarding the optimal choice. This study compared three commonly used patellar harvest site bone void fillers and assessed their impact on the frequency and severity of anterior knee pain. We hypothesised that calcium phosphate cement would result in lower postoperative anterior knee pain compared with autologous bone graft and demineralised bone matrix (DBM) due to its compressive modulus approximating cancellous bone. METHODS:Skeletally mature patients undergoing primary anterior cruciate ligament reconstruction with a bone-patellar tendon-bone autograft were enrolled. Exclusion criteria included age under 18, prior anterior cruciate ligament reconstruction, multiligament knee injury, coronal malalignment exceeding three degrees of varus or valgus, or less than 1 year of follow-up. Participants were randomly assigned to one of three groups: (1) autologous bone graft, (2) calcium phosphate cement or (3) DBM. Patient-reported outcomes were collected preoperatively and at 1 week, 6 weeks, 3 months, 6 months, 9 months and 12 months postoperatively. Analysis of variance and chi-square tests were used for statistical analysis. RESULTS:After applying exclusion criteria, 148 patients were included in the final analysis. No significant differences in visual analog scale pain scores were observed between cohorts at any postoperative interval (12-month, p = 0.598). Similarly, Kujala and Knee injury and Osteoarthritis Outcome scores did not differ significantly among the three cohorts at any time point (12-month, p = 0.878, p = 0.366). CONCLUSIONS:Filling the patellar harvest site defect with autologous bone graft, calcium phosphate cement, or DBM resulted in similar postoperative anterior knee pain following anterior cruciate ligament reconstruction with bone-patellar tendon-bone autograft. LEVEL OF EVIDENCE/METHODS:Level I.

ObjectiveTo describe recent trends in US MACI (autologous cultured chondrocytes on porcine collagen membrane) insurance approval rates, including the impact of defect location and the number of defects.DesignMyCartilageCare case management team provides insurance prior authorization support for potential MACI patients through Vericel Corporation, the manufacturer of MACI. Data from insurance claims from 2021 to 2022 were assessed for non-military patients aged 17 to 55 years. Insurance outcomes were summarized, with approval defined as pre-authorization or pre-determination for the MACI procedure being secured prior to the initiation of treatment or cases where an estimate of coverage was provided prior to the initiation of treatment, respectively.ResultsA total of 5,158 cases were identified. In total, 87.7% of MACI cases were approved on initial submission, 9.4% were approved on appeal, 2.4% were not appealed, and 0.5% were denied after appeal. A total of 51.4% of cases included a patella defect, with similar rates of approval: 87.4% approved on initial submission, 9.6% approved on appeal, 2.5% not appealed, 0.5% denied after appeal. 29.9% contained more than one defect which were approved at similar rates: 87.1% approved on initial submission, 10.2% approved on appeal, 2.3% not appealed, and 0.5% denied after appeal.ConclusionsMACI claims in the knee cartilage repair treatment algorithm are broadly supported by US third-party payers, with nearly 88% of all knee cartilage patients obtaining insurance approval on their initial submission and 97% of patients obtaining approval in total following appeal of initially denied claims. This is consistent across all groups including patella, non-patella, single, and multiple-defect cases.

BACKGROUND:Inflammatory biomarkers in an injured knee have been shown to predict outcomes, yet the role of the subsequent systemic inflammatory response to injury remains poorly understood. PURPOSE/OBJECTIVE:To investigate whether synovial fluid (SF) biomarkers from the contralateral uninjured knee could predict long-term patient-reported outcomes (PROs) for the operative knee in patients undergoing arthroscopic knee surgery. STUDY DESIGN/METHODS:Case series; Level of evidence, 4. METHODS:This retrospective analysis included patients undergoing knee SF aspiration before arthroscopy with ≥8 years of follow-up. SF was aspirated from both the injured and healthy contralateral knees, and concentrations of 10 pro- and anti-inflammatory biomarkers were quantified. Patients completed visual analog scale (VAS) for pain score, Lysholm, Tegner, and Knee injury and Osteoarthritis Outcome Score Physical Function Short Form (KOOS-PS) surveys preoperatively and at the final follow-up. Stepwise linear regression was performed to identify the most significant predictor(s) of PRO scores utilizing log-normalized contralateral biomarker concentration, age, body mass index, injury type, and Outerbridge grade as covariates. Concentrations from the contralateral knee were also compared with the injured knee to assess for correlations. RESULTS:= .006) score at the final follow-up. Contralateral concentrations of monocyte chemotactic protein 1, macrophage inflammatory protein 1β, vascular endothelial growth factor, and TIMP-1 were correlated with levels in the operative knee but at significantly lower concentrations. CONCLUSION/CONCLUSIONS:SF biomarker levels in the contralateral uninjured knee at the time of arthroscopy were predictive of long-term outcomes for the operative knee. Increased levels of pro-inflammatory biomarkers were predictive of worse outcomes, while anti-inflammatory cytokines predicted improved scores. These results suggest that unilateral knee injury can result in a broader systemic inflammatory response that influences long-term outcomes in patients.

High tibial osteotomy (HTO) is commonly used to correct excessive varus knee malalignment. Varus alignment places increased loads on the medial tibiofemoral joint, accelerating medical compartment degeneration. This article explores the benefits of HTO in correcting varus deformities and addresses concomitant procedures for managing medial compartment pathology, offering practical guidance for surgeons to optimize outcomes and restore knee function.

Articular cartilage lesions of the knee pose a significant clinical challenge due to the limited regenerative capacity of hyaline cartilage and the wide variability in patient presentation and lesion characteristics. Surface-based cartilage restoration techniques have evolved substantially, shifting from isolated marrow stimulation toward biologically enhanced strategies designed to improve repair tissue quality, durability, and clinical outcomes while preserving native joint anatomy. These techniques are primarily indicated for contained chondral defects without substantial subchondral bone compromise and include scaffold-augmented microfracture, particulated cartilage techniques using juvenile or adult allograft tissue, and matrix-associated autologous chondrocyte implantation (ACI). Selection among these options is driven by patient age, activity level, and expectations, as well as lesion-specific factors such as size, anatomic location, containment, and subchondral bone integrity. Single-stage approaches, including micronized cartilage extracellular matrix augmentation and particulated cartilage allografts, offer reduced procedural burden and avoidance of cell expansion, with favorable short- to mid-term outcomes for small to moderate lesions. In contrast, matrix-induced autologous chondrocyte implantation (MACI) is supported by randomized controlled trials and long-term cohort studies demonstrating sustained improvements in patient-reported outcomes (PROs) beyond 10 years, particularly in younger, active patients with larger isolated defects. Despite these advances, variability in imaging findings, complication profiles, and performance in the patellofemoral joint underscores the importance of appropriate patient selection, meticulous surgical technique, and structured postoperative rehabilitation. This review synthesizes current evidence regarding indications, surgical techniques, outcomes, and limitations of contemporary surface-based cartilage restoration options for the knee, providing a practical framework to guide clinical decision-making in joint preservation surgery.

BACKGROUND:The COVID-19 pandemic led to increased sedentary behavior and body mass index during 2020, which may decondition musculotendinous units and lead to increased risk for injury. As patients return to pre-COVID levels of activity, we hypothesize that there will be a resultant rebound increase in tendon ruptures. LEVEL OF EVIDENCE/METHODS:III, descriptive epidemiology study. METHODS:The electronic medical record was queried for current procedural terminology codes for tendon ruptures (Achilles, patella, quadriceps, hamstring, distal biceps, triceps, and pectoralis major) from January 2017 to December 2021 at a single academic urban center. Data were reviewed to ensure only acute tendon rupture repairs were included. The years 2017-2019 were used as a proxy for pre-COVID rates, 2020 as a proxy for the COVID quarantine, and 2021 as a proxy for "post-COVID" activity. Univariate analysis was performed for comparative data. RESULTS:A total of 1,879 patients (82.8% male, mean age 47.8 years) who sustained tendon injuries and underwent surgical repair were identified. There were 589 (31.3%) Achilles tendon repairs, 181 (9.6%) patella tendon repairs, 414 (22.0%) quadriceps tendon repairs, 100 (5.3%) hamstring tendon repairs, 397 (21.1%) distal biceps repairs, 105 (5.6%) triceps repairs, and 93 (4.9%) pectoralis tendon repairs. The total number of tendon injuries per year was 2017-357 (19.0%), 2018-380 (20.2%), 2019-380 (20.2%), 2020-308 (16.4%), and 2021-454 (24.2%). The rates in 2017, 2018, and 2019 were within 1% of each other, but there were a 3.8% decrease in rate of tendon injuries from 2019 to 2020 and a 7.8% increase in rate of tendon injuries from 2020 to 2021. When analyzed by quarter, a linear regression model demonstrated a statistically significant increase in case counts over the period from Q2 2020 to Q2 2021 (β = 21.20; 95% confidence interval = 13.62-28.78, P-value < .01). CONCLUSIONS:A "COVID rebound" of tendon rupture repairs in 2021 from a prolonged period of inactivity during 2020 occurred at a single academic center. As patients return to pre-COVID levels of activity that may be unsuitable to their deconditioned state, healthcare providers should counsel patients appropriately on return to activity or sport following long periods of induced inactivity.