Autologous Matrix-Induced Chondrogenesis for the Treatment of Hip Acetabular Chondral Lesions Demonstrates Improved Outcomes: A Systematic Review.

PURPOSE: To systematically investigate the outcomes of patients who underwent autologous matrix-induced chondrogenesis (AMIC) during hip arthroscopy for the treatment of acetabular chondral lesions due to femoroacetabular impingement syndrome. METHODS: PubMed and Cochrane were queried in June 2022 to conduct this systematic review using the following keywords: "femoroacetabular impingement," "arthroscopy," "microfracture," and "autologous matrix-induced chondrogenesis." Articles were included if they reported on patient-reported outcomes of AMIC during hip arthroscopy to treat chondral lesions of the hip. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Each study was queried for demographics, lesion classification, surgical treatment, patient-reported outcome scores, revision arthroscopy, and conversion to total hip arthroplasty (THA). A qualitative subanalysis was performed to compare patients undergoing AMIC to patients undergoing microfracture alone if included studies also assessed results of microfracture alone. RESULTS: Four studies met inclusion criteria and assessed 209 hips undergoing AMIC. The included studies consisted of 99 male and 110 female patients. Mean postoperative follow-up ranged from 1 to 8 years, and mean patient age ranged from 34.3 to 45 years. Three of the 4 included studies reported the modified Harris Hip Score, and all 3 of these studies reported statistically significant improvement in the modified Harris Hip Score at final follow-up (P < .001) with mean preoperative values ranging from 44.5 to 62.8 and mean postoperative values ranging from 78.8 to 95.8. Two of the 4 studies compared patients treated with AMIC to microfracture alone. In these 2 studies, the AMIC groups reported 0 patients converting to THA while the microfracture-alone groups reported a highly variable rate of conversion to THA (2%-32.6%). CONCLUSIONS: Patients who underwent hip arthroscopy and AMIC for the treatment of femoroacetabular impingement syndrome and acetabular chondral lesions demonstrated improved patient-reported outcomes and low rates of secondary surgeries at short-term follow-up. STUDY DESIGN: Level IV, systematic review of Level III and IV studies.

RatInABox, a toolkit for modelling locomotion and neuronal activity in continuous environments.

Generating synthetic locomotory and neural data is a useful yet cumbersome step commonly required to study theoretical models of the brain's role in spatial navigation. This process can be time consuming and, without a common framework, makes it difficult to reproduce or compare studies which each generate test data in different ways. In response, we present RatInABox, an open-source Python toolkit designed to model realistic rodent locomotion and generate synthetic neural data from spatially modulated cell types. This software provides users with (i) the ability to construct one- or two-dimensional environments with configurable barriers and visual cues, (ii) a physically realistic random motion model fitted to experimental data, (iii) rapid online calculation of neural data for many of the known self-location or velocity selective cell types in the hippocampal formation (including place cells, grid cells, boundary vector cells, head direction cells) and (iv) a framework for constructing custom cell types, multi-layer network models and data- or policy-controlled motion trajectories. The motion and neural models are spatially and temporally continuous as well as topographically sensitive to boundary conditions and walls. We demonstrate that out-of-the-box parameter settings replicate many aspects of rodent foraging behaviour such as velocity statistics and the tendency of rodents to over-explore walls. Numerous tutorial scripts are provided, including examples where RatInABox is used for decoding position from neural data or to solve a navigational reinforcement learning task. We hope this tool will significantly streamline computational research into the brain's role in navigation.

The brain is a complex system made up of over 100 billion neurons that interact to give rise to all sorts of behaviours. To understand how neural interactions enable distinct behaviours, neuroscientists often build computational models that can reproduce some of the interactions and behaviours observed in the brain. Unfortunately, good computational models can be hard to build, and it can be wasteful for different groups of scientists to each write their own software to model a similar system. Instead, it is more effective for scientists to share their code so that different models can be quickly built from an identical set of core elements. These toolkits should be well made, free and easy to use. One of the largest fields within neuroscience and machine learning concerns navigation: how does an organism ­ or an artificial agent ­ know where they are and how to get where they are going next? Scientists have identified many different types of neurons in the brain that are important for navigation. For example, 'place cells' fire whenever the animal is at a specific location, and 'head direction cells' fire when the animal's head is pointed in a particular direction. These and other neurons interact to support navigational behaviours. Despite the importance of navigation, no single computational toolkit existed to model these behaviours and neural circuits. To fill this gap, George et al. developed RatInABox, a toolkit that contains the building blocks needed to study the brain's role in navigation. One module, called the 'Environment', contains code for making arenas of arbitrary shapes. A second module contains code describing how organisms or 'Agents' move around the arena and interact with walls, objects, and other agents. A final module, called 'Neurons', contains code that reproduces the reponse patterns of well-known cell types involved in navigation. This module also has code for more generic, trainable neurons that can be used to model how machines and organisms learn. Environments, Agents and Neurons can be combined and modified in many ways, allowing users to rapidly construct complex models and generate artificial datasets. A diversity of tutorials, including how the package can be used for reinforcement learning (the study of how agents learn optimal motions) are provided. RatInABox will benefit many researchers interested in neuroscience and machine learning. It is particularly well positioned to bridge the gap between these two fields and drive a more brain-inspired approach to machine learning. RatInABox's userbase is fast growing, and it is quickly becoming one of the core computational tools used by scientists to understand the brain and navigation. Additionally, its ease of use and visual clarity means that it can be used as an accessible teaching tool for learning about spatial representations and navigation.

An Update on Orthobiologics: Cautious Optimism.

Orthobiologics are rapidly growing in use given their potential to augment healing for multiple musculoskeletal conditions. Orthobiologics consist of a variety of treatments including platelet-rich plasma and stem cells that provide conceptual appeal in providing local delivery of growth factors and inflammation modulation. The lack of standardization in nomenclature and applications within the literature has led to a paucity of high-quality evidence to support their frequent use. The purpose of this review was to describe the current landscape of orthobiologics and the most recent evidence regarding their use.

Rapid learning of predictive maps with STDP and theta phase precession.

The predictive map hypothesis is a promising candidate principle for hippocampal function. A favoured formalisation of this hypothesis, called the successor representation, proposes that each place cell encodes the expected state occupancy of its target location in the near future. This predictive framework is supported by behavioural as well as electrophysiological evidence and has desirable consequences for both the generalisability and efficiency of reinforcement learning algorithms. However, it is unclear how the successor representation might be learnt in the brain. Error-driven temporal difference learning, commonly used to learn successor representations in artificial agents, is not known to be implemented in hippocampal networks. Instead, we demonstrate that spike-timing dependent plasticity (STDP), a form of Hebbian learning, acting on temporally compressed trajectories known as 'theta sweeps', is sufficient to rapidly learn a close approximation to the successor representation. The model is biologically plausible - it uses spiking neurons modulated by theta-band oscillations, diffuse and overlapping place cell-like state representations, and experimentally matched parameters. We show how this model maps onto known aspects of hippocampal circuitry and explains substantial variance in the temporal difference successor matrix, consequently giving rise to place cells that demonstrate experimentally observed successor representation-related phenomena including backwards expansion on a 1D track and elongation near walls in 2D. Finally, our model provides insight into the observed topographical ordering of place field sizes along the dorsal-ventral axis by showing this is necessary to prevent the detrimental mixing of larger place fields, which encode longer timescale successor representations, with more fine-grained predictions of spatial location.

Determining Clinically Meaningful Thresholds for the Hip Outcome Score Sport-Specific Subscale in Athletes Undergoing Hip Arthroscopy for Femoroacetabular Impingement Syndrome.

BACKGROUND: The minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), substantial clinical benefit (SCB), and maximum outcome improvement (MOI) satisfaction threshold for the Hip Outcome Score Sport-Specific Subscale (HOS-SSS) have not been established in athletes undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS). PURPOSE: To determine threshold MCID, PASS, SCB, and MOI satisfaction threshold values for the HOS-SSS in athletes undergoing hip arthroscopy for FAIS at minimum 2-year follow-up. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 3. METHODS: Anchor questions were administered to recreational, organized amateur, high school, college, and professional athletes who underwent primary hip arthroscopy for FAIS between May 2015 and March 2019. Patients were included if they were younger than 50 years, answered the anchor questions, and had preoperative and minimum 2-year follow-up for the HOS-SSS, modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), and visual analog scale (VAS) for pain. Exclusion criteria were Tönnis grade >1, hip dysplasia (lateral center-edge angle <18°), and previous ipsilateral hip surgery or conditions. Receiver operating characteristic (ROC) analysis was used to determine PASS, SCB, and MOI satisfaction for the HOS-SSS. Two distribution methods were used to calculate MCID for HOS-SSS. RESULTS: A total of 225 athletes who underwent primary hip arthroscopy met the inclusion criteria. Of those athletes, 200 (88.9%) who had minimum 2-year follow-up and information regarding return to sport (RTS) were included. The cohort included 124 (62.0%) women and 76 (38.0%) men with a mean ± standard deviation age of 29.4 ± 10.4 years, body mass index of 25.6 ± 5.4, and follow-up of 29.5 ± 5.1 months. Athletes experienced significant improvements in HOS-SSS, mHHS, NAHS, and VAS from preoperative to latest postoperative follow-up (P < .001), and mean satisfaction was 8.2. The RTS rate was 83.7%. ROC analysis determined that the PASS, MOI satisfaction threshold, SCB absolute score, SCB change score, and MCID (baseline/change score methods) for the HOS-SSS were 77.0, 44.6%, 92.7, 30.6, and 10.6, respectively, with athletes achieving thresholds at high rates (80.0%, 80.5%, 45.0%, 54.0%, and 79.5%, respectively). CONCLUSION: This study identified values for the HOS-SSS that can be used to define clinically meaningful outcomes in athletes after primary hip arthroscopy for FAIS. The PASS, MOI satisfaction threshold, SCB absolute score, SCB change score, and MCID for the HOS-SSS at minimum 2-year follow-up in athletes after primary hip arthroscopy were 77.0, 44.6%, 92.7, 30.6, and 10.6, respectively.

Minimum 2-Year Outcomes and Return to Sports of Competitive Athletes Who Undergo Subspine Decompression During Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome and Subspine Impingement: A Propensity-Matched Controlled Study.

BACKGROUND: Patient-reported outcomes (PROs) and return to sports (RTS) have not been established in athletes undergoing primary hip arthroscopy and subspine decompression for femoroacetabular impingement syndrome (FAIS) and subspine impingement (SSI). PURPOSE: (1) To report minimum 2-year PROs and RTS in competitive athletes undergoing primary hip arthroscopy for treatment of FAIS with subspine decompression for treatment of SSI and (2) to compare clinical results with a matched control group of athletes without SSI. STUDY DESIGN: Cohort study, Level of evidence, 3. METHODS: Data were reviewed for professional, collegiate, and high school athletes undergoing primary hip arthroscopy for FAIS with arthroscopic subspine decompression for SSI between February 2011 and October 2018. Inclusion criteria included preoperative and minimum 2-year follow-up scores for the modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sport Specific Subscale, and visual analog scale for pain. Rates of achieving the minimal clinically important difference (MCID) were also calculated. For comparison, athletes in the SSI group were propensity matched according to age at the time of surgery, sex, body mass index, lateral center-edge angle, alpha angle, sport level, acetabular labrum articular disruption grade, and sport type to a control group of athletes without SSI. RESULTS: A total of 30 SSI athletes were included in the study, with a mean plus or minus standard deviation follow-up of 32.1 ± 7.1 months and age of 20.9 ± 5.7 years. The SSI cohort demonstrated significant improvement in all recorded PROs (P < .001), returned to sports at high rates (88.5%), and achieved the MCID for the Hip Outcome Score-Sport Specific Subscale at a high rate (80.0%). Furthermore, these patients had a low rate of undergoing revision surgery (6.7%). When compared with a propensity-matched control group of 59 athletes, the SSI group demonstrated similar rates of RTS, revision, and achieving the MCID for all PROs. CONCLUSION: Competitive athletes with FAIS and SSI who underwent primary hip arthroscopy and subspine decompression had favorable outcomes and high RTS rates at minimum 2-year follow-up. These results were comparable with those of a control group of athletes without SSI undergoing primary hip arthroscopy.

Revision Hip Arthroscopy With Labral Reconstruction for Irreparable Labral Tears in Athletes: Minimum 2-Year Outcomes With a Benchmark Control Group.

BACKGROUND: The incidence of revision hip arthroscopy with labral reconstruction in athletes is increasing. However, the outcomes of revision hip arthroscopy with labral reconstruction in athletes have not been well established. PURPOSES: (1) To report minimum 2-year patient-reported outcome (PRO) scores and return to sports (RTS) characteristics for high-level athletes undergoing revision hip arthroscopy with labral reconstruction and (2) to compare clinical results with those of a propensity-matched control group of high-level athletes undergoing revision hip arthroscopy with labral repair. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were prospectively collected and retrospectively reviewed for athletes at any level who underwent a revision hip arthroscopy and a labral reconstruction between April 2010 and March 2019. Minimum 2-year PROs were reported for the modified Harris Hip Score (mHHS), the Nonarthritic Hip Score (NAHS), the Hip Outcome Score-Sport Specific Subscale (HOS-SSS), the visual analog scale (VAS) for pain, and RTS. The percentages of athletes achieving the minimal clinically important difference (MCID) and the maximum outcome improvement satisfaction threshold (MOIST) were also recorded. These patients were propensity matched in a 1: 1 ratio to athletes undergoing revision hip arthroscopy with labral repair for comparison. RESULTS: A total of 46 athletes (N = 47 hips) were reported from 50 (n = 51 hips) athletes who underwent revision with labral reconstruction. A subanalysis of 30 propensity-matched athletes undergoing revision labral reconstruction was performed, with a mean follow-up time of 26.3 ± 2.4 months and an age of 28.5 ± 10.1 years, and compared with a revision labral repair group. Significant improvements were obtained for the mHHS, the NAHS, the HOS-SSS, and the VAS from preoperative to the latest follow-up (P < .001), with an achievement MCID rate of 61.5%, 72%, 62.5%, and 76.9% for the mHHS, the NAHS, the HOS-SSS, and the VAS, respectively. The rate for re-revision surgery (2 tertiary arthroscopy and 1 conversion to total hip arthroplasty) was 10%, and 14 patients (63.6%) were able to RTS. Improvements in PROs, rates of achieving MCID/MOIST, rate of re-revision surgery (re-revision hip arthroscopy, P = .671; conversion to total hip arthroplasty, P > .999), and RTS rate (P = .337) were similar when compared with those of the propensity-matched control labral repair group (P > .05). CONCLUSION: Revision hip arthroscopy with labral reconstruction, in the context of an irreparable labral tear, seems to be a valid treatment option in the athletic population, demonstrating significant improvements in all PROs and low rates of undergoing revision surgery. Athletes experienced a similar magnitude of improvement in PROs, RTS rate, and revision surgery rate to that of a propensity-matched control group of athletes undergoing revision hip arthroscopy with labral repair.

Competitive Athletes with Femoroacetabular Impingement and Painful Internal Snapping Treated Arthroscopically with Intrabursal Iliopsoas Fractional Lengthening: High Rate of Return to Sport and Favorable Midterm Functional Outcomes.

BACKGROUND: Athletes with femoroacetabular impingement syndrome (FAIS) who undergo hip arthroscopy with iliopsoas fractional lengthening (IFL) in the context of painful internal snapping have demonstrated favorable patient-reported outcomes (PROs), return to sport (RTS), and resolution of internal snapping symptoms at short term follow-up. Midterm outcomes have not been established. PURPOSES: (1) To report minimum 5-year PROs and RTS rate in competitive athletes who underwent primary hip arthroscopy for FAIS and intra-bursal IFL for painful internal snapping and (2) to compare these clinical results with those of a propensity score-matched control group of competitive athletes who underwent primary hip arthroscopy without painful internal snapping and IFL. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were reviewed for consecutive surgeries performed by a single surgeon between February 2010 and December 2013. Patients were considered eligible if they were professional, collegiate, or high school athletes and received a primary hip arthroscopy for FAIS and intra-bursal IFL without extended capsulotomy for painful internal snapping. Indications for IFL were painful internal snapping on preoperative physical examination. Inclusion criteria were preoperative and minimum 5-year follow-up scores for the modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sport Specific Subscale, and visual analog scale for pain. Rates of achieving the minimal clinically important difference were also reported. For comparison, athletes in the IFL group were propensity matched by age, sex, body mass index, lateral and anterior center-edge angles, and sports level to a control group of athletes without internal snapping who underwent primary hip arthroscopy for FAIS without IFL. RESULTS: A total of 105 competitive athletes in the IFL group were included in the study with a follow-up of 66.8 ± 6.9 months (mean ± SD). The IFL cohort showed significant improvement in all recorded PROs at minimum 5-year follow-up (P < .001). Furthermore, they demonstrated favorable rates of achieving the minimal clinically important difference for the modified Harris Hip Score (82.0%), Nonarthritic Hip Score (85.4%), and Hip Outcome Score-Sport Specific Subscale (82.8%). Further, 89.5% of athletes in the IFL cohort successfully returned to sport. A total of 42 athletes in the IFL group were propensity matched to 54 control athletes. When groups were compared, they demonstrated similar improvement in PROs and rates of RTS, revision arthroscopy, and achieving psychometric thresholds. CONCLUSION: Competitive athletes undergoing primary hip arthroscopy and intra-bursal IFL in the context of FAIS and painful internal snapping demonstrated favorable PROs and RTS rate at minimum 5-year follow-up. These results were comparable with those of a control group of athletes not requiring IFL.

Effect of Cigarette Smoking on Outcomes in Patients Undergoing Primary Hip Arthroscopy and Labral Reconstruction: A Propensity-Matched Controlled Study With Minimum 2-Year Follow-up.

BACKGROUND: There is a paucity of literature evaluating the effect of cigarette smoking on outcomes in patients undergoing hip arthroscopy and labral reconstruction. PURPOSE: (1) To report minimum 2-year patient-reported outcome (PRO) scores for patients who smoke cigarettes and underwent primary hip arthroscopic labral reconstruction and (2) to compare these results with those of a propensity-matched control group of patients who have never smoked. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were collected for all patients who underwent primary hip arthroscopy for labral reconstruction between January 2011 and January 2019. Patients were eligible for the study if they indicated that they smoked cigarettes within 1 month of surgery and had minimum 2-year postoperative outcome scores for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and the visual analog scale (VAS) for pain. The percentage of patients achieving the minimal clinically important difference (MCID) and patient-acceptable symptom state (PASS) was recorded. Rates of revision surgery were also documented. These patients were then propensity matched in a 1:3 ratio to patients who had never smoked (controls) for comparison. RESULTS: A total of 20 patients (20 hips) were included with a mean follow-up of 39.9 ± 13.0 months and mean age of 41.4 ± 10.4 years. These patients demonstrated significant improvement from preoperatively to the minimum 2-year follow-up for mHHS, NAHS, and VAS (P < .05). They also achieved MCID for mHHS and VAS at acceptable rates, 70% for both. When outcomes were compared with those of 60 control patients (60 hips), patients who smoke demonstrated lower preoperative PRO scores but similar minimum 2-year postoperative PRO scores for mHHS and NAHS. Patients who smoke demonstrated lower rates of achieving PASS for mHHS (55% vs 75%) and NAHS (40% vs 61.7%) compared with controls; however, these findings were not statistically significant. Rates of secondary surgery were statistically significantly higher in the smoking group compared with controls (25% vs 5%; P = .031). Survivorship for the smoking patients was 80% and 98.3% for the control group. At the two-year mark survivorship was 90% for the smoking group and 100% for the control group (P = .06). CONCLUSION: While smokers can still derive significant improvement from hip arthroscopy, their ultimate functional outcome and rate of secondary surgeries are inferior to those of nonsmokers. As smoking is a significant and modifiable risk factor, we should continue to counsel smokers on smoking cessation prior to and after surgery.