IntroductionLittle is known about the impact of articular cartilage lesions on knee joint biomechanics.ObjectivesThis investigation aimed to determine the gait characteristics of patients with symptomatic articular cartilage defects of the knee.MethodsGait analyses were performed at a regional joint preservation centre. Assessments were completed on a treadmill with a 15-camera 3D motion-capture system. Participants walked for two minutes at a self-selected speed at 0° inclination. The resulting kinematic and spatiotemporal parameters were averaged across 20 consecutive gait cycles. Paired t-tests or Wilcoxon ranked tests were performed on the data to compare biomechanical parameters between knees (α=0.05).ResultsPatients (n=30) walked at an average speed of 3.0±0.7km/h with a cadence of 60.4±16.2 steps/minute. Step lengths were comparable between limbs (p=0.595). Maximum flexion during swing did not differ between knees (p=0.507), but were lower than previously reported healthy adults. In the frontal plane, both knees remained in adduction throughout the gait cycle (p=0.385). The maximal adduction reported in both knees were greater than previously reported for healthy adults. Maximal internal-external rotation patterns were comparable in stance (p=0.475) and swing (p=0.762) and to previous literature.ConclusionGait characteristics were generally comparable between injured and contralateral knees of patients with symptomatic cartilage lesions of the knee. However, some parameters of gait in the sagittal and frontal plane were pathological when compared to previously published data from healthy adults.

Purpose: The purpose of this study was to compare the long-term objective biomechanical and functional parameters of a high-flexion total knee arthroplasty (TKA) design against healthy older adults to determine whether knee biomechanics are comparable in both populations.Methods: One cohort of patients with a primary TKA, and a cohort of healthy adults over 55 years old with no musculoskeletal deficits or arthritis participated. Bilateral knee range of motion (RoM) was assessed with a goniometer, and gait patterns were analysed with a three-dimensional-motion capture system. An arthrometer quantified the anterior-posterior laxity of each knee. Statistical analyses were performed in SPSS software (alpha = 0.05).Results: Twenty-three knees were replaced in 20 patients. At 9.8 +/- 3.1 years postoperatively, patients' knees had a statistically significantly poorer RoM than healthy controls' knees (n = 23) due to limited flexion; p < 0.0001. Patients also failed to achieve the same degree of knee flexion as controls during downhill gait. No kinematic differences were observed during mid-flexion in level nor downhill gait; a state that has been associated with instability (p = 0.614; not significant [n.s]). There were no differences between groups in knee laxity (n.s).Conclusion: Patients in this study had similar gait patterns to healthy older adults during mid-flexion and were no more likely than the healthy controls to exhibit anterior-posterior translation of the knee > 7 mm; a known risk factor of instability. However, the knee flexion range was poorer. This likely led to bilateral pathological knee flexion patterns during downhill gait. Level of Evidence: Level III.

Background Chondral injuries in the knee, whether isolated or accompanying other injuries are found in as many as 60% of arthroscopic examinations. Although current research has identified negative outcomes for patients with a BMI >30kg/m2 undergoing chondral repair, our understanding of the relationship between pre-surgery BMI and post-operative patient reported outcomes across all BMI categories remains lacking. Through the International Cartilage Regeneration and Joint Preservation Society (ICRS) Patient Registry, this study aimed to explore this relationship, taking into account sex variations. Methods The ICRS Patient Registry was used to extract the data for this study. The outcomes in focus were the Knee Osteoarthritis Outcome Score (KOOS) and EQ-5D scores. Pearson and Spearman correlation methods were applied and the level of significance was set as α = 0.05. Results Of 3,194 Registry patients at the time of data extraction, 1,757 had undergone a surgical procedure, and 336 of these had complete KOOS or EQ-5D scores available for 6-weeks, 6-months, and 1-year post-operation. Analyses revealed that neither male (average BMI – 28.2kg/m2) nor female (average BMI – 25.3 kg/m2) datasets indicated a correlation between BMI and the patient-reported outcomes. Conclusion BMI, irrespective of sex, is not correlated with patient-reported outcomes in patients enrolled in the ICRS Registry with a BMI <30kg/m2. Although BMIs in the overweight classification were not associated with poorer outcomes than BMIs in the normal classification, the current literature continues to support the notion that a BMI >30kg/m2 is linked to poor cartilage repair and failure.

Introduction: Chondral injuries in the knee, whether isolated or accompanying other injuries are found in as many as 60% of arthroscopic examinations. Although current research has identified negative outcomes for patients with a body mass index (BMI) >30kg/m2 undergoing chondral repair, our understanding of the relationship between presurgery BMI and postoperative patient-reported outcomes across all BMI categories remains lacking. Objectives: Through the International Cartilage Regeneration and Joint Preservation Society (ICRS) Patient Registry, this study aimed to explore this relationship, taking into account sex variations. Methods: The ICRS Patient Registry was used to extract the data for this study. The outcomes in focus were the Knee Osteoarthritis Outcome Score (KOOS) and EQ-5D scores. Pearson and Spearman correlation methods were applied and the level of significance was set as α= 0.05. Results: Of 3194 Registry patients at the time of data extraction, 1757 had undergone a surgical procedure, and 336 of these had complete KOOS or EQ-5D scores available for 6-week, 6-month, and 1-year postoperation. Analyses revealed that neither male (average BMI – 28.2 kg/m2) nor female (average BMI – 25.3 kg/m2) data sets indicated a correlation between BMI and the patient-reported outcomes. Conclusions: BMI, irrespective of sex, is not correlated with patient-reported outcomes in patients enrolled in the ICRS Registry with a BMI <30 kg/m2. Although BMIs in the overweight classification were not associated with poorer outcomes than BMIs in the normal classification, the current literature continues to support the notion that a BMI >30 kg/m2 is linked to poor cartilage repair and failure.

Total knee arthroplasty (TKA) aims to alleviate pain and restore joint biomechanics to an equivalent degree to age-matched peers. Zimmer Biomet's Nexgen TKA was the most common implant in the UK between 2003 and 2016. This study compared the biomechanical outcomes of the Nexgen implant against a cohort of healthy older adults to determine whether knee biomechanics is restored post-TKA. Patients with a primary Nexgen TKA and healthy adults >55 years old with no musculoskeletal deficits or diagnosis of arthritis were recruited locally. Eligible participants attended one research appointment. Bilateral knee range of motion (RoM) was assessed with a goniometer. A motorised arthrometer (GENOUROB) was then used to quantify the anterior-posterior laxity of each knee. Finally, gait patterns were analysed on a treadmill. An 8-camera Vicon motion capture system generated the biomechanical model. Preliminary statistical analyses were performed in SPSS (α = 0.05; required sample size for ongoing study: n=21 per group). The patient cohort (n=21) was older and had a greater BMI than the comparative group (n=13). Patients also had significantly poorer RoM than healthy older adults. However, there were no inter-group differences in knee laxity, walking speed or cadence. Gait kinematics were comparable in the sagittal plane during stance phase. Peak knee flexion during swing phase was lower in the patient group, however (49.0° vs 41.1°). Preliminary results suggest that knee laxity and some spatiotemporal and kinematic parameters of gait are restored in Nexgen TKA patients. While knee RoM remains significantly poorer in the patient cohort, an average RoM of >110° was achieved. This suggests the implant provides sufficient RoM for most activities of daily living. Further improvements to knee kinematics may necessitate additional rehabilitation. Future recruitment drives will concentrate on adults over the age of 70 for improved inter-group comparability.

AbstractIntroductionThis study compared biomechanical and functional parameters of a total knee arthroplasty (TKA) implant (Cemented Zimmer Hi-Flex) against healthy older adults to determine whether knee biomechanics was restored in this patient population.MethodologyPatients with a primary TKA and healthy adults >55 years old with no musculoskeletal deficits or arthritis participated. Bilateral knee range of motion (RoM) was assessed with a goniometer, then gait patterns were analysed with a 3D motion-capture system. An arthrometer then quantified anterior-posterior laxity of each knee. Statistical analyses were performed in SPSS (α=0.05; required sample size: n=21 per group).Results25 knees were replaced in 21 patients. Nine presented with fixed flexion deformities (FFD) (13.3±5.6°). FFDs were abolished intraoperatively, and the average flexion increased from 124.8±9.1° to 130.9±5.8°. At 9.6±3.2 years postoperatively, the patients achieved poorer RoM than healthy controls (n=23); p<0.0001. These differences were due to limited flexion in the knee. Patients also failed to achieve the same degree of flexion as controls bilaterally during gait. No differences were observed during mid-flexion; a state that has been associated with instability (p=0.614). There were no differences between groups in knee laxity.ConclusionPatients in this study had similar gait patterns to healthy older adults during mid-flexion, and were no more likely to exhibit anterior-posterior translation of the knee >7mm; a known risk factor of instability. However, the flexion range was poorer. This led to bilateral pathological knee flexion patterns during gait. Further research should identify the cause of these limitations.

Purpose: Osteoarthritis is a prolific condition in an increasingly ageing and obese population. Research into treatments of this condition and their efficacy are vital. Outcomes of high tibial osteotomy (HTO) for the varus knee is widely reported. There is less evidence for HTO in the valgus knee. This systematic review aimed to compile all literature reporting the outcomes of HTO to correct the valgus knee, focusing on post-operative clinical outcomes. Methods: Ovid MEDLINE, Embase and Web of Science were searched using key terms: Osteoarthritis [All Fields] AND High tibial osteotomy [All Fields] AND Lateral OR Valgus [All Fields]. Papers were screened for eligibility based on an inclusion and exclusion criteria. Full text screening was completed by two reviewers and data was extracted from the agreed included papers by one reviewer. Quality assessments of the papers were also conducted. PROSPERO ID: CRD42021239045. Results: Across 17 papers reporting 517 knees, the average pre-operative femorotibial and hip-knee-ankle angles were corrected from 13.6 +/- 7.0 degrees and 4.9 +/- 1.9 degrees valgus to 2.8 +/- 2.9 degrees D and 1.2 +/- 1.7 degrees varus. Studies show that the procedure is successful at offloading the lateral knee compartment and some evidence it can delay the need for a total knee replacement. However, its impact on overall quality of life remains poorly understood. Conclusions: High tibial osteotomy may be a viable treatment option for valgus knee deformities caused by lateral compartment osteoarthritis. Nevertheless, research into the procedure remains limited. Importantly, our understanding of the relationship between the achieved alignment and outcome remains largely unknown.

IntroductionSome patients with cartilage defects of the knee are known to report similar quality of life (QoL) scores to patients listed for total knee arthroplasty. However, it is unknown whether patients waiting to undergo injections for a cartilage injury perceive their symptoms and QoL to be equivalent to those awaiting surgery.ObjectivesCompare the pre-treatment status of patients undergoing a knee injection or surgical intervention for cartilage lesions. Hypothesis: There will be no clinical difference in scores between the two cohorts.MethodsAnonymous data from the International Cartilage Regeneration and Joint Preservation Society (ICRS) Registry were exported: Demographics, type of intervention, pre-treatment Knee Osteoarthritis Outcome Scores (KOOS) and Visual Analogue Scores (VAS). The required sample size was 273 per cohort. Statistical analyses compared the scores of each cohort (α = 0.05).Results1,578 patients were included (993 surgeries vs 585 injections). The surgical cohort were 30 years younger than the injection cohort (p<0.0001). There were no clinically significant differences in KOOS or VAS. However, KOOS aggregate scores, KOOS Pain, and VAS were statistically poorer in the injection cohort (p<0.0001; p=0.04; p=0.001). KOOS QoL was poorer in the surgical cohort (p < 0.0001).ConclusionsOur null hypothesis was accepted, as there were no clinically significant differences in the scores. Thus, both cohorts perceived their level of disability and severity of symptoms to be equivalent. Nevertheless, statistical analyses suggested that the younger surgical cohort perceived their QoL to be poorer, while pain levels were worse in the older injection cohort.

Abstract: We previously conducted a single-arm, prospective study in which 31 patients (mean age [and standard deviation], 42.5 ± 11.3 years) with cartilage lesions were treated with use of the BioPoly Partial Resurfacing Knee Implant. Treatment outcomes were compared with those reported for the standard of care, microfracture. We found that the mean KOOS (Knee injury and Osteoarthritis Outcome Score) Quality of Life score at 5 years in the BioPoly cohort was noninferior to (p = 0.004), and indeed greater than (p = 0.021), that in the microfracture cohort. The BioPoly cohort demonstrated improvement in the mean scores for all KOOS domains at every postoperative time point (p < 0.025). The mean score for the visual analog scale (VAS) for pain significantly improved (p < 0.025) at all time points up to 4 years and trended toward significant improvement at 5 years (p = 0.027). This study indicated that the BioPoly implant was safe, provided significant improvement starting at 6 months and continuing to 5 years, and provided greater improvement than microfracture for some outcome measures. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Abstract:. We previously conducted a single-arm, prospective study in which 31 patients (mean age [and standard deviation], 42.5 ± 11.3 years) with cartilage lesions were treated with use of the BioPoly Partial Resurfacing Knee Implant. Treatment outcomes were compared with those reported for the standard of care, microfracture. We found that the mean KOOS (Knee injury and Osteoarthritis Outcome Score) Quality of Life score at 5 years in the BioPoly cohort was noninferior to (p = 0.004), and indeed greater than (p = 0.021), that in the microfracture cohort. The BioPoly cohort demonstrated improvement in the mean scores for all KOOS domains at every postoperative time point (p < 0.025). The mean score for the visual analog scale (VAS) for pain significantly improved (p < 0.025) at all time points up to 4 years and trended toward significant improvement at 5 years (p = 0.027). This study indicated that the BioPoly implant was safe, provided significant improvement starting at 6 months and continuing to 5 years, and provided greater improvement than microfracture for some outcome measures. Level of Evidence:. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Introduction: Some patients with cartilage defects of the knee are known to report similar quality of life (QoL) scores to patients listed for total knee arthroplasty. However, it is unknown whether patients waiting to undergo injections for a cartilage injury perceive their symptoms and QoL to be equivalent to those awaiting surgery. Objectives: Compare the pretreatment status of patients undergoing a knee injection or surgical intervention for cartilage lesions. The hypothesis was that there would be no clinical difference in scores between the 2 cohorts. Methods: Anonymous data from the International Cartilage Regeneration and Joint Preservation Society Registry were exported: demographics, type of intervention, pretreatment Knee Injury and Osteoarthritis Outcome Scores (KOOS) and Visual Analog Scores (VAS). The required sample size was 273 per cohort. Statistical analyses were used to compare the scores of each cohort (α = 0.05). Results: One thousand five hundred seventy-eight patients were included (993 surgeries vs 585 injections). The surgical cohort was 30 years younger than the injection cohort (P < .0001). There were no clinically significant differences in KOOS or VAS. However, KOOS aggregate scores, KOOS pain, and VAS were statistically poorer in the injection cohort (P < .0001; P = .04; P = .001). KOOS QoL was poorer in the surgical cohort (P < .0001). Conclusions: Our null hypothesis was accepted, as there were no clinically significant differences in the scores. Thus, both cohorts perceived their level of disability and severity of symptoms to be equivalent. Nevertheless, statistical analyses suggested that the younger surgical cohort perceived their QoL to be poorer, while pain levels were worse in the older injection cohort.

Sports injuries, trauma and the globally ageing and obese population require increasing levels of knee surgery. Shared decision making has replaced the paternalistic approach to patient management. Evidence-based medicine underpins surgical treatment strategies, from consenting an individual patient to national healthcare system design. The evolution of successful knee-related registries starting from specific arthroplasty registries has given rise to ligament reconstruction, osteotomy and cartilage surgery registries developing as platforms for surgical outcome data collection. Stakeholders include surgeons and their patients, researchers, healthcare systems, as well as the funding insurers and governments. Lately, implant manufacturers have also been mandated to perform postmarket surveillance with some hoping to base that on registry data. Aiming to assess the current status of knee-related registries, we performed a comprehensive literature and web search, which yielded 23 arthroplasty, 8 ligament, 4 osteotomy and 3 articular cartilage registries. Registries were evaluated for their scope, measured variables, impact and limitations. Registries have many advantages as they aim to increase awareness of outcomes; identify trends in practice over time, early failing implants, outlier surgeon or institution performance; and assist postmarketing surveillance. International collaborations have highlighted variations in practice. The limitations of registries are discussed in detail. Inconsistencies are found in collected data and measured variables. Potential measurement and selection biases are outlined. Without mandated data collection and with apparent issues such as unverified patient reporting of complications, registries are not designed to replace adverse event recording in place of a proper safety and efficacy study, as demanded by regulators. Registry 'big data' can provide evidence of associations of problems. However, registries cannot provide evidence of causation. Hence, without careful consideration of the data and its limitations, registry data are at risk of incorrectly drawn conclusions and the potential of misuse of the results. That must be guarded against. Looking at the future, registry operators benefit from a collective experience of running registries as they mature, allowing for improvements across specialties. Large-scale registries are not only of merit, improving with stakeholder acceptance, but also are critical in furthering our understanding of our patients' outcomes. In doing so, they are a critical element for our future scientific discourse.

Objective The International Cartilage Regeneration and Joint Preservation Society’s (ICRS’s) global registry, aims to be the best source of information for patients and an unbiased resource of evidence-based medicine for scientists and clinicians working to help those unfortunate enough to suffer the pain and disability associated with articular cartilage lesions. This article constitutes the scientific summary of the reports’ main findings. Design The article outlines the historical precedents in the development of orthopedic registries from the earliest tumor registries, then local arthroplasty databases that led ultimately to international collaborations between national arthroplasty and soft tissue registries. The ICRS global cartilage registry was designed from the outset as a GDPR (General Data Protection Regulation) compliant, multilingual, multinational cooperative system. It is a web-based user-friendly, live in 11 languages by end 2019, which can be accessed via https://cartilage.org/society/icrs-patient-registry/ . Patients and clinicians enter data by smartphone, tablet, or computer on any knee cartilage regeneration and joint preservation treatment, including the use of focal arthroplasty. Knee Injury and Osteoarthritis Outcome Score and Kujala patient-reported outcome measures are collected preoperatively, 6 months, 12 months, and annually for ten years thereafter. EQ-5D data collection will allow cost-effectiveness analysis. Strengths, weaknesses, and future plans are discussed. Results Since inception the registry has 264 users across 50 countries. Major findings are presented and discussed, while the entire first ICRS global registry report is available at https://cartilage.org/society/icrs-patient-registry/registry-annual-reports/ . Conclusion. A measure of the maturity of any registry is the publication of its findings in the peer reviewed literature. With the publication of its first report, the ICRS global registry has achieved that milestone.

Objective This systematic review aimed to determine whether coronal angular corrections correlate with patient reported outcomes following valgus-producing high tibial osteotomy (HTO). Design Ovid MEDLINE, Embase, and Web of Science were systematically searched. Studies that reported hip-knee-ankle angles (HKA) or femorotibial angles (FTA), and the Oxford Knee Score (OKS), visual analogue scale (VAS) score, Knee Injury and Osteoarthritis Outcome Score (KOOS), or EQ-5D before and after valgus-producing HTO were eligible. Correlation analyses were performed where appropriate to investigate the relationships between variables. PROSPERO ID: CRD42019135467. Results This study included 39 articles including 50 cohorts. VAS was reported in 22 studies, OKS in 9, KOOS in 12 and EQ-5D in 2. The HKA angle was corrected from 7.1° ± 1.7° varus to 2.3° ± 1.7° valgus at final follow-up. The FTA changed from 3.0° ± 2.0° varus to 7.7° ± 1.3° valgus. Outcome scores improved with clinical and statistical significance postoperatively. Spearman correlations for nonparametric data revealed greater changes in knee alignment were moderately associated with larger improvements in VAS scores ( r = 0.50). Furthermore, those who experienced greater changes in alignment showed larger improvements in the KOOS Activity and Quality of Life domains ( r = 0.72 and r = 0.51, respectively). Conclusion On average, patients did not achieve the “ideal correction” of 3° to 6° valgus postoperatively. Nevertheless, statistical and clinical improvements in patient-reported outcome measure scores were consistently reported. This suggests that the “ideal correction” may be more flexible than 3° to 6°.

Most knee osteoarthritis and meniscectomy studies focus on osteoarthritis in the tibiofemoral joint and ignore the patellofemoral joint. This study aims to assess the long-term effects of total meniscectomy on the patellofemoral joint. To our knowledge, this is the only study of osteoarthritis in the patellofemoral joint following meniscectomy that extends to a 40-year follow-up period. Twenty-two patients with osteoarthritis were evaluated at a mean of 40 years post-meniscectomy using standardised weight-bearing radiographs of the operated and non-operated knees. Patellofemoral joint osteoarthritis was diagnosed by the presence of osteophytes and joint space narrowing to less than 5 mm. Kellgren and Lawrence scores were calculated from the radiographs. Patellofemoral joint osteoarthritis and tibiofemoral joint osteoarthritis were correlated with International Knee Documentation Committee scores and range of movement measurements. A significant difference was observed between the operated and non-operated knees in terms of patellofemoral joint osteophyte formation. There was a significant difference in tibiofemoral joint Kellgren and Lawrence scores, International Knee Documentation Committee scores and range of movement measurements between knees with lateral facet patellofemoral joint space of < 5 mm and > 5 mm. This study shows an association between open total meniscectomy and patellofemoral joint osteoarthritis at 40 years following surgery. There was also an association between patellofemoral joint space narrowing in the lateral facet and tibiofemoral joint osteoarthritis. Possible causes include altered biomechanical loading patterns following meniscectomy as well as global processes within the knee.