Faculty Bibliography

OBJECTIVE:The purpose of this study was to compare the short-term clinical outcomes of matrix-induced autologous chondrocyte implantation (MACI) to those seen following traditional autologous chondrocyte implantation (ACI) in the management of symptomatic cartilage lesions of the knee. METHODS:This was a retrospective cohort study of patients who underwent either ACI or MACI from January 2011 to March 2018. Patients with a minimum postoperative follow-up of 18 months were contacted. Demographic information, intraoperative findings, and patient-reported functional outcomes scores were collected. Comparisons were made between the two cell-based cartilage repair techniques. RESULTS:Fifty-six patients were included in the study (39 ACI, 17 MACI). Visual analog scale (VAS) for pain scores improved significantly in both groups, with MACI patients demonstrating significantly lower postoperative pain scores compared to those treated with ACI. In the ACI group, there was a decrease in the Tegner Activity score compared to the preoperative baseline, while no significant difference was seen between pre- and postoperative activity levels in the MACI group. Patients were generally satisfied with the outcome of their procedures, and there was no significant difference in satisfaction between groups. No patients re-quired additional surgery during the follow-up period. CONCLUSION/CONCLUSIONS:Both ACI and MACI demonstrated good short-term postoperative clinical results with improved pain and activity levels compared to the preoperative baseline. Patients treated with the MACI technique demonstrated greater reductions in pain scores compared to ACI, and while ACI resulted in a decrease in levels of postoperative activity, activity levels for MACI remained stable.

BACKGROUND:Synovial fluid biomarkers are well studied indicators of inflammation and healing in the setting of orthopedic injuries. However, it has not been studied if patients with one or more allergies have a difference in the concentrations of synovial fluid inflammatory cytokines compared to patients without allergies. The purpose of the current study is to analyze the concentration of 10 pro- and anti-inflammatory cytokines in the synovial fluid of isolated ACL injury patients with and without at least one allergy. STUDY DESIGN/METHODS:Retrospective Case-Control. METHODS:A database of patients who underwent surgery for isolated ACL injury between September 2011 and July 2023 was analyzed. All patients had SF aspirated from the operative knee prior to the surgical incision and the concentrations of pre- and anti-inflammatory biomarkers were quantified. From this cohort, 24 patients were identified to have allergies by chart review. These patients were matched 1:1 to 24 patients without allergies based on age and sex. RESULTS:There were no significant differences between the allergy and no allergy cohorts with respect to age (28.5 ± 10.3 vs. 29.5 ± 8.9, p = 0.76) and sex (70.8 % female vs. 70.8 % female, p = 1.00). The allergy cohort had a decreased concentration of TIMP-1 (492.41 ± 616.20 ng/mL vs. 1041.48 ± 942.04 ng/mL, p = 0.03) and IL-1Ra (101.70 ± 93.37 pg/mL vs. 359.94 ± 399.77 pg/mL, p = 0.01) compared to patients without allergies. A linear regression analysis found a significant association between increasing number of patients reported allergies and decreasing concentration of TIMP-1 (β = -231.59, p = 0.03) and IL-1Ra (β = -71.69p = 0.03) concentrations when controlling for age and sex. Finally, the allergy cohort was found to have a significantly higher value for the VAS pain scale at the time of surgery (26.84 ± 24.73 vs. 7.37 ± 10.98, p < 0.01) compared to those without an allergy. CONCLUSION/CONCLUSIONS:Patients undergoing ACL reconstruction with at least one allergy were found to have decreased concentrations of the anti-inflammatory cytokines TIMP-1 and IL-1Ra in their synovial fluid compared to those without allergies on the day of surgery. Furthermore, an increase in total number of allergies was found to be an associated with a decrease in TIMP-1 and IL-1Ra levels. Finally, the allergy cohort also had a higher value for the VAS pain scale at the time of surgery, implicating the role of a patient's innate immune system to their biologic and symptomatic response to injury.

PURPOSE/OBJECTIVE:The purpose of this study is to describe the postoperative psychological state of patients following osteochondral allograft (OCA) transplantation in the knee and to determine whether patient-perceived kinesiophobia is associated with the rate of return to sport (RTS). METHODS:A retrospective review of the electronic medical record at a single institution was conducted for all patients that underwent OCA transplantation from January 2010 to 2020. Patient-reported outcomes including the visual analog scale (VAS), knee injury and osteoarthritis outcome score (KOOS) and the Tampa scale of kinesiophobia-11 (TSK-11) were collected. Patients were surveyed regarding their postoperative RTS status. RESULTS:A total of 38 patients (52.6% female) were included in our analysis. Overall, 24 patients (63.2%) returned to sport with 12 (50%) of these patients returning at a lower level of play. When comparing patients that return to sport to those that did not, patients that return had significantly superior KOOS pain (p = 0.019) and KOOS QOL (p = 0.011). Measures of kinesiophobia (TSK-11) were significantly higher among patients that did not return to sport (p = 0.014), while satisfaction (n.s.) and pain intensity (n.s.) were comparable between groups. Logistic regression models controlling for demographic factors, VAS pain scores and lesion size showed that for every one-point increase in TSK-11 kinesiophobia score, patients were 1.33 times more likely to return to sport at a lower level (p = 0.009). For every one-point increase in TSK-11 scores KOOS QOL decreased by 2.4 points (p < 0.001). CONCLUSION/CONCLUSIONS:Fear of reinjury decreases the likelihood that patients will return to their preoperative level of sport after OCA transplantation. Patients that do not return to sport report significantly greater fear of reinjury and inferior clinical outcomes, despite similar levels of satisfaction and pain compared to those that return. LEVEL OF EVIDENCE/METHODS:Level III.

Osteoarthritis (OA) is the most common joint disease. Currently there are no effective methods that simultaneously prevent joint degeneration and reduce pain¹. Although limited evidence suggests the existence of voltage-gated sodium channels (VGSCs) in chondrocytes², their expression and function in chondrocytes and in OA remain essentially unknown. Here we identify Na_v1.7 as an OA-associated VGSC and demonstrate that human OA chondrocytes express functional Na_v1.7 channels, with a density of 0.1 to 0.15 channels per µm² and 350 to 525 channels per cell. Serial genetic ablation of Na_v1.7 in multiple mouse models demonstrates that Na_v1.7 expressed in dorsal root ganglia neurons is involved in pain, whereas Na_v1.7 in chondrocytes regulates OA progression. Pharmacological blockade of Na_v1.7 with selective or clinically used pan-Na_v channel blockers significantly ameliorates the progression of structural joint damage, and reduces OA pain behaviour. Mechanistically, Na_v1.7 blockers regulate intracellular Ca²⁺ signalling and the chondrocyte secretome, which in turn affects chondrocyte biology and OA progression. Identification of Na_v1.7 as a novel chondrocyte-expressed, OA-associated channel uncovers a dual target for the development of disease-modifying and non-opioid pain relief treatment for OA.

Stem cell therapies have become widely popular in orthopaedic surgery, with a recent interest in adipose-derived therapeutics. Adipose-derived mesenchymal signaling cells (ADSCs) and micronized adipose tissue (MAT) are unique therapies derived from different processing methods. Characterizing the most influential studies in lipoaspirate research can help clarify controversies in definitions, identify core literature, and further collective knowledge for educational purposes. The Science Citation Index Expanded subsection of the Web of Science Core Collection was systematically searched to identify the top 50 most cited publications (based on citation/year) on orthopaedic ADSCs or MAT research. Publication and study characteristics were extracted and reported using descriptive statistics. Level of evidence was assessed for applicable studies, and Spearman correlations were calculated to assess the relationship between citation data and level of evidence. The top 50 articles were published between the years 2003 and 2020, with 78% published in the year 2010 or later. The mean number of citations was 103.1 ± 81.1. The mean citation rate was 12.4 ± 6.0 citations per year. Of the 21 studies for which level of evidence was assessed, the majority were level III (10, 47.6%). The single study design most common among the top 50 cited articles was in vitro basic science studies (17 studies, 34%). Twenty-nine articles (58%) were classified as basic science or translational. Application to treat knee osteoarthritis was the most common focus of studies (14 studies, 28%), followed by in vitro analysis of growth factor and cell signaling markers (11 studies, 22%). No correlation was found between rank, citation rate, or year of publication and level of evidence. This study provides a current landscape on the most cited articles in lipoaspirates in orthopaedic surgery. With the expansion of ADSCs and MAT in the past two decades, this study provides the first historical landmark of the literature and a launching point for future research. Studies should explicitly state their processing methodology and whether their study investigates ADSCs or MAT to avoid misinformation.

PURPOSE/OBJECTIVE:To investigate the rate of return to sports and sport psychological readiness between patients who underwent isolated MPFLR (iMPFLR) compared to a matched cohort of patients who underwent MPFLR with anteromedializing tibial tubercle osteotomy (MPFLR/TTO). METHODS:Patients who underwent primary MPFLR with or without TTO for recurrent patellar instability were retrospectively reviewed from 2012 to 2020 at a single institution. Preinjury sport and work information, Kujala, Tegner, Visual Analogue Score for pain, satisfaction and MPFL-Return to Sport after Injury (MPFL-RSI) score were collected. Two readers independently measured the tibial tuberosity-trochlear groove distance, Caton-Deschamps index and Dejour classification for trochlear dysplasia. Patients in iMPFLR and MPFLR/TTO groups were matched 1:1 on age, sex, body mass index and follow-up length. Multivariate regression analysis was performed to determine whether the MPFL-RSI was associated with a return to sport. RESULTS:This study included 74 patients at mean follow-up of 52.5 months (range: 24-117). These groups returned to sport at similar rates (iMPFLR: 67.6%, MPFLR/TTO: 73.0%, not significant [ns]), though iMPFLR patients returned more quickly (8.4 vs. 12.8 months, p = 0.019). Rates of return to preinjury sport level were also similar (45.9% vs. 40.5%, ns). Patients with Dejour B/C took more time to return to sport compared to patients with mild/no trochlear pathology (13.8 vs. 7.9 months, p = 0.003). Increasing MPFL-RSI score was significantly predictive of the overall return to sport (odds ratio [OR]: 1.08, 95% confidence interval [CI] [1.03, 1.13], p < 0.001) and return to preinjury level (OR: 1.07, 95% CI [1.04, 1.13], p < 0.001). Most patients in iMPFLR and MPFLR/TTO groups resumed work (95.7% vs. 88.5%, ns), though iMPFLR patients who returned to preinjury work levels did so more quickly (1.7 vs. 4.6 months, p = 0.005). CONCLUSION/CONCLUSIONS:Patients who underwent MPFLR with anteromedializing TTO demonstrated similar rates of return to sport and psychological readiness compared to an isolated MPFLR matched comparison group, though iMPFLRs returned more quickly. Patients with more severe trochlear pathology required more time to return to sports. LEVEL OF EVIDENCE/METHODS:Level III.

PURPOSE/OBJECTIVE:To compare clinical outcomes, rate of return to sports, and psychological readiness among patients undergoing anterior cruciate ligament reconstruction (ACLR) with and without concomitant Segond fracture. METHODS:We retrospectively identified patients who underwent primary ACLR from January 2012 to December 2020 with minimum 2-year follow-up. Exclusion criteria were additional ligamentous injury, age <16 years, or a concomitant lateral augmentation procedure. Preoperative knee radiographs were reviewed to identify Segond fractures. Identified patients were matched 1:2 to controls by age/sex/body mass index/graft type. Charts were reviewed for pre- and postoperative knee stability. Surveys administered included preinjury sport participation and return status, Lysholm score, Tegner activity scale, and ACL-Return to Sport Index (ACL-RSI), a metric of psychological sport readiness. Multivariable logistic regression was conducted to identify predictors of return to sport. RESULTS:There were 120 patients who were included in the final analysis (40 Segond, 80 controls) at a mean follow-up of 5.7 ± 2.4 years. A total of 52.5% of patients received bone-patellar tendon-bone autograft. The overall rate of return to sport was 79.5% in the Segond group compared with an 83.8% rate of return in the control group (P = .569). In total, 48.7% of the Segond group and 56.8% of the control group returned to their preinjury level of sport (P = .415). Lysholm (89.6 ± 10.3 vs 85.4 ± 16.7, P = .296), Tegner (5.7 ± 1.8 vs 6.1 ± 2.2, P = .723), and ACL-RSI (62.2 ± 25.4 vs 56.6 ± 25.4, P = .578) scores were similar between Segond and control groups. There was a single graft failure in the Segond group 5 years' postoperatively. Increasing ACL-RSI score was significantly predictive of return to sport (P < .001). CONCLUSIONS:Patients who had an ACL tear and a concomitant Segond fracture who underwent isolated ACLR without lateral augmentation procedures had similar clinical outcomes and rates of return sport compared with a matched isolated ACLR control group at minimum 2-year follow-up. There was no significant difference in psychological readiness between groups as measured by the ACL-RSI. LEVEL OF EVIDENCE/METHODS:Level III, retrospective cohort study.

PURPOSE OF REVIEW/OBJECTIVE:Numerous cartilage restoration techniques have proven to be effective in the treatment of articular cartilage defects. The ultimate goal of these procedures is to improve pain and function, thereby increasing the likelihood of a patient's return to physical activity. Postoperative rehabilitation is a key component for a successful and expedient return to activities. The purpose of this article is to review the current literature regarding common surgical options, rehabilitation protocols, and performance outcomes after operative treatment of articular cartilage defects. RECENT FINDINGS/RESULTS:Studies have demonstrated improved short- to long-term outcomes in a majority of techniques. However, the clinical benefits of microfracture are short-lived, which has led to the use of alternative procedures. Rehabilitation protocols are not standardized, but emphasis has been placed on bracing, weightbearing, early continuous passive range of motion, and strengthening to improve function. There is growing evidence to suggest that accelerated rehabilitation after matrix-induced autologous chondrocyte implantation may result in superior outcomes compared to delayed rehabilitation. Overall, most techniques result in satisfactory rates of return to play, though existing comparative studies typically include patients with heterogeneous pathology, complicating effective synthesis of outcomes data. In appropriately selected patients, cartilage restoration procedures after articular cartilage injury result in favorable patient-reported clinical outcomes and high rates of return to play. While studies emphasize the critical role that rehabilitation plays with respect to outcomes after surgery, there are substantial inconsistencies in protocols across techniques.

BACKGROUND:Force plate-based jump testing may serve as a potential alternative to traditional return to sport (RTS) testing batteries. The purpose of our study was to identify force plate jump metrics that were predictive of RTS test findings in patients who were at least six months postoperative following anterior cruciate ligament reconstruction (ACLR). METHODS:We conducted a cross-sectional study of patients who underwent ACLR at our center and were at least six months postoperative. Subjects completed a multimodal Institutional RTS (IRTS) testing battery which included range of motion (ROM) testing and isokinetic quadriceps strength testing. Subjects also completed a countermovement jump testing protocol on a commercially-available force plate. Jump metrics predictive of IRTS test findings were identified using multivariable linear and logistic regression with stepwise selection. Model significance was assessed at α=0.002. RESULTS:Sixteen patients (7M, 9F) were enrolled in our study with median age of 29 years (range 20-47). Relative concentric impulse was positively predictive of knee flexion active ROM (β=7.07, P=0.01) and passive ROM (β=9.79, P=0.003). Maximum power was positively predictive of quadriceps strength at 60 deg/s (β=3.27, P<0.001) and 180 deg/s (β=2.46, P<0.001). Center-of-pressure (COP) shift acceleration along the force plate X-axis was negatively predictive of Bunkie lateral test score (β=-945, P<0.001) and medial test score (β=-839, P=0.03). CONCLUSIONS:Force plate-derived vertical jump testing metrics are predictive of certain components of a multimodal RTS physical assessment for ACLR patients, including knee flexion ROM, quadriceps strength on isokinetic testing, and Bunkie Test performance.