The effect of post-traumatic chondropathy on the functional state of knee joints in athletes during the basketball game.

The relevance of the study is conditioned upon the widespread occurrence of knee injuries in athletes when playing basketball, in particular, damage to the cartilage system of the knee joint. Such a feature of injury causes the fact that basketball players may develop post-traumatic chondropathy with a subsequent change in the functional state of knee joints, which is inextricably linked with a decrease in the quality of life, the occurrence of pain syndrome, shortening of career duration, an increased risk of surgical interventions, and possible disability in the long-term perspective. This paper is aimed at uncovering modern ideas about the impact of post-traumatic chondropathy on the functional state of knee joints in athletes during basketball games. The method for this paper was the search for relevant studies concerning the formulated problem, the collection of information and drawing conclusions. Given the character of the basketball game, knee injuries, both acute and chronic, are widespread among athletes of this sport, including cartilaginous defects of the knee joint, which often occur in athletes. The materials of the paper are of practical value for sports medicine doctors, physiotherapists, traumatologists since it presents the main mechanisms of knee injuries in athletes when playing basketball and the possible consequences of these injuries in the long term.

Using Decellularized Magnetic Microrobots to Deliver Functional Cells for Cartilage Regeneration.

The use of natural cartilage extracellular matrix (ECM) has gained widespread attention in the field of cartilage tissue engineering. However, current approaches for delivering functional scaffolds for osteoarthritis (OA) therapy rely on knee surgery, which is limited by the narrow and complex structure of the articular cavity and carries the risk of injuring surrounding tissues. This work introduces a novel cell microcarrier, magnetized cartilage ECM-derived scaffolds (M-CEDSs), which are derived from decellularized natural porcine cartilage ECM. Human bone marrow mesenchymal stem cells are selected for their therapeutic potential in OA treatments. Owing to their natural composition, M-CEDSs have a biomechanical environment similar to that of human cartilage and can efficiently load functional cells while maintaining high mobility. The cells are released spontaneously at a target location for at least 20 days. Furthermore, cell-seeded M-CEDSs show better knee joint function recovery than control groups 3 weeks after surgery in preclinical experiments, and ex vivo experiments reveal that M-CEDSs can rapidly aggregate inside tissue samples. This work demonstrates the use of decellularized microrobots for cell delivery and their in vivo therapeutic effects in preclinical tests.

Quantitative ultrashort echo time MR imaging of knee osteochondral junction: An ex vivo feasibility study.

Compositional changes can occur in the osteochondral junction (OCJ) during the early stages and progressive disease evolution of knee osteoarthritis (OA). However, conventional magnetic resonance imaging (MRI) sequences are not able to image these regions efficiently because of the OCJ region's rapid signal decay. The development of new sequences able to image and quantify OCJ region is therefore highly desirable. We developed a comprehensive ultrashort echo time (UTE) MRI protocol for quantitative assessment of OCJ region in the knee joint, including UTE variable flip angle technique for T1 mapping, UTE magnetization transfer (UTE-MT) modeling for macromolecular proton fraction (MMF) mapping, UTE adiabatic T1ρ (UTE-AdiabT1ρ) sequence for T1ρ mapping, and multi-echo UTE sequence for T2* mapping. B1 mapping based on the UTE actual flip angle technique was utilized for B1 correction in T1, MMF, and T1ρ measurements. Ten normal and one abnormal cadaveric human knee joints were scanned on a 3T clinical MRI scanner to investigate the feasibility of OCJ imaging using the proposed protocol. Volumetric T1, MMF, T1ρ, and T2* maps of the OCJ, as well as the superficial and full-thickness cartilage regions, were successfully produced using the quantitative UTE imaging protocol. Significantly lower T1, T1ρ, and T2* relaxation times were observed in the OCJ region compared with those observed in both the superficial and full-thickness cartilage regions, whereas MMF showed significantly higher values in the OCJ region. In addition, all four UTE biomarkers showed substantial differences in the OCJ region between normal and abnormal knees. These results indicate that the newly developed 3D quantitative UTE imaging techniques are feasible for T1, MMF, T1ρ, and T2* mapping of knee OCJ, representative of a promising approach for the evaluation of compositional changes in early knee OA.

Association of Knee Osteoarthritis and Flexion Contracture With Localized Tibial Articular Cartilage Loss: Data From the Osteoarthritis Initiative.

OBJECTIVE: To evaluate whether a knee flexion contracture (FC) was associated with localized tibial articular cartilage loss over a 1-year period using Osteoarthritis Initiative quantitative data. METHODS: Five hundred seventy-eight participants from a previously established nested case-control study of people with radiographic knee OA with or without progression, based on radiographs and symptoms, had their knee range of extension measured at baseline and received magnetic resonance imaging (MRI) at baseline and 1 year. The tibial articular cartilage of the medial and lateral condyles was segmented into anterior, center, and posterior regions. We tested for associations between knee FC (defined as lack of extension to 0°), and localized changes in tibial articular cartilage thickness or percent of denuded bone (0 mm thickness) after 1 year relative to baseline using ANOVA, controlling for baseline MRI outcomes and clinical factors. RESULTS: Knee FC was associated with denuded bone in the medial condyle center (ß 0.44, 95% CI 0.02-0.86) and preserved cartilage thickness in the medial condyle posterior (ß 0.01, 95% CI 0.002-0.03) regions. CONCLUSION: Knee FC unloading the tibial center region and loading the posterior region was associated with localized articular cartilage loss centrally and preserved articular cartilage posteriorly. These findings are consistent with knee FC negatively affecting unloaded tibial articular cartilage.

Modeling of the native knee with kinematic data derived from experiments using the VIVO™ joint simulator: a feasibility study.

BACKGROUND: Despite advances in total knee arthroplasty, many patients are still unsatisfied with the functional outcome. Multibody simulations enable a more efficient exploration of independent variables compared to experimental studies. However, to what extent numerical models can fully reproduce knee joint kinematics is still unclear. Hence, models must be validated with different test scenarios before being applied to biomechanical questions. METHODS: In our feasibility study, we analyzed a human knee specimen on a six degree of freedom joint simulator, applying a passive flexion and different laxity tests with sequential states of ligament resection while recording the joint kinematics. Simultaneously, we generated a subject-specific multibody model of the native tibiofemoral joint considering ligaments and contact between articulating cartilage surfaces. RESULTS: Our experimental data on the sequential states of ligament resection aligned well with the literature. The model-based knee joint kinematics during passive flexion showed good agreement with the experiment, with root-mean-square errors of less than 1.61 mm for translations and 2.1° for knee joint rotations. During laxity tests, the experiment measured up to 8 mm of anteroposterior laxity, while the numerical model allowed less than 3 mm. CONCLUSION: Although the multibody model showed good agreement to the experimental kinematics during passive flexion, the validation showed that ligament parameters used in this feasibility study are too stiff to replicate experimental laxity tests correctly. Hence, more precise subject-specific ligament parameters have to be identified in the future through model optimization.

Evaluation of an Unloading Concept for Knee Osteoarthritis: A Pilot Study in a Small Patient Group.

Joint compressive forces have been identified as a risk factor for osteoarthritis disease progression. Therefore, unloader braces are a common treatment with the aim of relieving pain, but their effects are not clearly documented in the literature. A knee brace concept was tested with the aim of reducing joint loads and pain in knee osteoarthritis patients by applying an extension moment exclusively during the stance phase. The ideal effects were evaluated during gait based on musculoskeletal modeling of six patients, and experimental tests with a prototype brace were conducted on one patient. The effects were evaluated using electromyography measurements and musculoskeletal models to evaluate the muscle activation and knee compressive forces, respectively. The ideal brace simulations revealed a varying reduction of the first peak knee force between 3.5% and 33.8% across six patients whereas the second peak was unaffected. The prototype reduced the peak vasti muscle activation with 7.9% and musculoskeletal models showed a reduction of the first peak knee compressive force of up to 26.3%. However, the prototype brace increased the knee joint force impulse of up to 17.1% and no immediate pain reduction was observed. The reduction of the first peak knee compressive force, using a prototype on a single patient, indicates a promising effect from an applied knee extension moment for reducing knee joint loads during normal gait. However, further clinical experiments with this brace method are required to evaluate the long-term effects on both pain and disease progression in knee osteoarthritis patients.

Predicting Knee Joint Contact Forces During Normal Walking Using Kinematic Inputs With a Long-Short Term Neural Network.

Knee joint contact forces are commonly estimated via surrogate measures (i.e., external knee adduction moments or musculoskeletal modeling). Despite its capabilities, modeling is not optimal for clinicians or persons with limited experience. The purpose of this study was to design a novel prediction method for knee joint contact forces that is simplistic in terms of required inputs. This study included marker trajectories and instrumented knee forces during normal walking from the "Grand Challenge" (n = 6) and "CAMS" (n = 2) datasets. Inverse kinematics were used to derive stance phase hip (sagittal, frontal, transverse), knee (sagittal, frontal), ankle (sagittal), and trunk (frontal) kinematics. A long-short term memory network (LSTM) was created using matlab to predict medial and lateral knee force waveforms using combinations of the kinematics. The Grand Challenge and CAMS datasets trained and tested the network, respectively. Musculoskeletal modeling forces were derived using static optimization and joint reaction tools in OpenSim. Waveform accuracy was determined as the proportion of variance and root-mean-square error between network predictions and in vivo data. The LSTM network was highly accurate for medial forces (R2 = 0.77, RMSE = 0.27 BW) and required only frontal hip and knee and sagittal hip and ankle kinematics. Modeled medial force predictions were excellent (R2 = 0.77, RMSE = 0.33 BW). Lateral force predictions were poor for both methods (LSTM R2 = 0.18, RMSE = 0.08 BW; modeling R2 = 0.21, RMSE = 0.54 BW). The designed LSTM network outperformed most reports of musculoskeletal modeling, including those reached in this study, revealing knee joint forces can accurately be predicted by using only kinematic input variables.

Inactivation and replantation of the knee joint: an infeasible surgical method.

BACKGROUND: The inactivation and replantation of autologous tumor bones are important surgical methods for limb salvage in patients with malignancies. Currently, there are few reports on the inactivation and replantation of the knee joint. In this study, we aimed to evaluate the feasibility of our surgical approach. METHODS: This is a retrospective case series study. We retrospectively collected the clinical data of patients with sarcoma treated with knee joint inactivation and replantation and analyzed the efficacy of this surgical method. The bone healing and complications in these patients after inactivated autograft replantation were assessed. RESULTS: This study included 16 patients. Fifteen patients had osteosarcoma, and one had Ewing's sarcoma. The average length of the inactivated bone is 20.2 cm (range 13.5-25.3 cm). All the patients underwent internal plate fixation. The average follow-up duration was 30 months (range 8-60 months). Before the data deadline of this study, eight (50%) patients were still alive, and eight (50%) died of sarcoma metastasis. Eight (50%) patients achieved bone healing at the diaphysis site of the inactivated tumor bone, with an average bone healing time of 21.9 months (range, 12-36 months). Five (31%) patients died due to metastases and did not achieve bone healing. Two (12.5%) patients did not achieve bone healing because of infection, and one (6.3%) patient underwent amputation due to tumor recurrence. Ten (62.5%) patients experienced fractures around the joint ends of the inactivated replanted bone, and eight of these ten patients were combined with joint dislocation. CONCLUSION: The incidence of joint deformities after the knee-joint inactivation and replantation is extremely high and is not recommended for use.

Cultural adaptation and validation of the knee injury and osteoarthritis outcome score into Sinhala language in patients with primary knee osteoarthritis: a cross-sectional study.

BACKGROUND: Knee Injury and Osteoarthritis Outcome Score (KOOS) scale is a patient-reported outcome measurement tool. It evaluates both short- and long-term consequences of knee injury and primary osteoarthritis. This study aims to translate and validate the KOOS scale for a Sinhala-speaking Sri Lankan population. METHODS: A cross sectional study was conducted in three hospitals. Four hundred and fifteen patients comprising 185 males and 227 females (3 subjects did not reveal their gender) with knee osteoarthritis (KOA) participated in the study. Seventy nine participants without KOA were recruited as controls. The functionality and quality of life level in patients and healthy participants were assessed using translated versions of the KOOS and Short Form-36 (SF-36) scales. Internal consistency of the instrument was assessed by Cronbach alpha. Construct validity and test-retest reliability were examined using the Intraclass Correlation Coefficient (ICC). Confirmatory Factor Analysis (CFA) was used to assess factorial validity. RESULTS: The mean age (± sd) of the KOA subjects was 54.9 (± 9.2) years and for the control group was 49.2 (± 8.0) years. Majority of the respondents were female and Sinhalese in both groups. Internal consistency reliability was high (Cronbach's alpha values ≥ 0.70). The test-retest reliability was excellent with the intraclass correlation coefficient for all subscales being above 0.90. Construct validity was assessed by the magnitude of the correlation coefficient between KOOS and SF-36 subscale scores. KOOS Pain scale moderately correlated with SF-36 bodily pain (Pearson's r = 0.41). SF-36 physical function scores had a weak positive correlation with all KOOS subscales and SF-36 emotional wellbeing was not significantly correlated with KOOS Quality of Life (QoL) subscale. A five-factor Confirmatory Factor Analysis (CFA) model yielded a Comparative Fit Index (CFI) = 0.950, Tucker Lewis Index (TLI) = 0.946, Root Mean Square Error of Approximation (RMSEA) = 0.082 and Standardised Root Mean squared Residual (SRMR) = 0.072. CONCLUSION: The Sinhala translation of the KOOS scale is a reliable and valid instrument to assess KOA in a Sinhala-speaking Sri Lankan population. Studies to assess its use as a scale to evaluate responsiveness are recommended.

A home-based tele-rehabilitation exercise system for patients after knee replacement surgery.

BACKGROUND: Knee arthritis is a destructive disorder that affects the knee joints and causes pain and reduced mobility. Drug treatments, weight loss, and exercise control the symptoms of the disease, but these methods only delay the disease process and eventually, knee joint replacement surgery will be needed. After surgery, with the help of a proper physiotherapy program, full recovery takes an average of 6-12 months. However, currently, there is no similar tool to facilitate this process in Iran. OBJECTIVE: The purpose of this research is to design and develop the prototype of a rehabilitation system for patients after knee replacement surgery, which provides patients with information and appropriate physiotherapy programs. METHODS: This study was development-applied and was done in three stages. In the first stage, the needs and content of education and therapeutic exercises were prepared in the form of a checklist, and then the necessity of each item was checked in the evaluation sessions. In the second stage, the prototype of the system was developed using Adobe XD software and based on the requirements approved from the previous stage. In the third stage, the usability of the program was analyzed from the point of view of experts using the exploratory evaluation method with Nielsen's 13 principles of usability. RESULTS: At first, the system requirements were extracted and prepared in two checklists of content (51 exercises) and capabilities (60 items). Then after a survey of experts based on the Delphi technique, content information (43 exercises) and functional and non-functional requirements (53 items) were obtained. A survey of experts helped to finalize the information elements, categorize them, and prepare the final version of the checklists. Based on this, the system requirements were classified into 11 categories, and the training content was classified into 3 training periods. Finally, the design and development of the system was done. This system has admin, physician, and patient user interfaces. The result of usability showed that this system is efficient and there are only a few problems in the feature of helping users to detect and recover from errors. CONCLUSION: It seems necessary to develop a system based on the principles of usability by therapists and rehabilitation specialists to train and monitor the remote rehabilitation process of patients after knee joint replacement at home. And the importance of involving stakeholders in the design and development of remote rehabilitation systems is not hidden from anyone. Kara system has all of the above.

An imageology-based feasibility study of plating posterolateral tibial plateau fractures via an anterolateral trans-fibular-head approach.

BACKGROUND: There are many difficulties in the reduction and fixation of the tibial plateau fractures involving posterolateral quadrant using general plates via traditional approaches. By imaging the area above the fibulae capitulum, this study was performed to investigate the feasibility of the trans-fibular-head approach and to design an ideal anatomical plate. METHODS: MRI and CT scans of the knee joint were collected from 205 healthy volunteers (103 males, 102 females). Gender and height were used to divide the volunteers into groups separately: (1) A1 group and A2 group according to gender, (2) B1 group and B2 group according to height. Based on the images, several parameters were defined and measured to describe the space above the head of the fibula. In addition, differences in these parameters between genders and height were compared. RESULTS: The narrowest distance in the bony region was (10.96 ± 1.39) mm, (5.41 ± 0.97 mm) in the bone-ligament region. The narrowest distance of bony region in the A1 group was more than that in the A2 group (11.21 ± 1.62 mm, 10.85 ± 1.47 mm, p = 0.029). The narrowest distance of the bony region was (10.21 ± 1.42) mm and (11.65 ± 1.39) mm in the B1 group and B2 group, respectively (p = 0.002). The narrowest distance of the bone-ligament region was (5.39 ± 0.78) mm and (5.22 ± 1.21) mm in the A1 group and A2 group, respectively. No statistically significant differences were observed between the A1 group and the A2 group in terms of the narrowest distance of the bone-ligament region. In the B1 group, the narrowest distance of the bone-ligament region (5.18 ± 0.71 mm) was not significantly less than that (5.31 ± 0.91 mm) in the B2 group. CONCLUSION: The space above the fibular capitellum was ample enough to place the plate for treating tibial plateau fractures involving posterolateral quadrant. The divisions of the lateral tibial plateau by 3-dimensional CT and the parameters of each region were crucial for providing guidance for designing the anatomical plate for the trans-fibular-head approach.

Comparison of needle and conventional arthroscopy for visualisation of predefined anatomical structures of the knee joint: a feasibility study in human cadavers and patients.

BACKGROUND: In terms of the optics used for Knee arthroscopy, a large number of different endoscopes are currently available. However, the use of the 30° optics in knee arthroscopy has been established as the standard procedure for many years. As early as the 1990s, needle arthroscopy was occasionally used as a diagnostic tool. In addition to the development of conventional optics technology in terms of camera and resolution, needle arthroscopes are now available with chip-on-tip image sensor technology. To date, no study has compared the performance of this kind of needle arthroscopy versus standard arthroscopy in the clinical setting in terms of the visibility of anatomical landmarks. In this monocentric prospective feasibility study, our aim was to evaluate predefined anatomical landmarks of the knee joint using needle arthroscopy (0° optics) and conventional knee arthroscopy (30° optics) and compare their performance during knee surgery. METHODS: Examinations were performed on eight cadavers and seven patients who required elective knee arthroscopy. Two surgeons independently performed the examinations on these 15 knee joints, so that we were able to compare a total of 30 examinations. The focus was on the anatomical landmarks that could be visualized during a conventional diagnostic knee arthroscopy procedure. The quality of visibility was evaluated using a questionnaire. RESULTS: In summary, the average visibility for all the anatomic landmarks was rated 4.98/ 5 for the arthroscopy using 30° optics. For needle arthroscopy, an average score of 4.89/ 5 was obtained. Comparatively, the needle arthroscope showed slightly limited visibility of the retropatellar gliding surface in eight (4.5/ 5 vs. 5/ 5), medial rim of the patella in four (4.85/ 5 vs. 5/ 5), and suprapatellar recess in four (4.83/ 5 vs. 5/ 5) cases. Needle arthroscopy was slightly better at visualizing the posterior horn of the medial meniscus in four knee joints (4.9/ 5 vs. 4.85/ 5). CONCLUSION: Needle arthroscopy is a promising technology with advantages in terms of minimally invasive access and good visibility of anatomical landmarks. However, it also highlights some limitations, particularly in cases with challenging anatomy or the need for a wide field of view.

Comparison of knee joint and temporomandibular joint development in pig embryos.

Although the knee joint (KNJ) and temporomandibular joint (TMJ) all belong to the synovial joint, there are many differences in developmental origin, joint structure and articular cartilage type. Studies of joint development in embryos have been performed, mainly using poultry and rodents. However, KNJ and TMJ in poultry and rodents differ from those in humans in several ways. Very little work has been done on the embryonic development of KNJ and TMJ in large mammals. Several studies have shown that pigs are ideal animals for embryonic development research. Embryonic day 30 (E30), E35, E45, E55, E75, E90, Postnatal day 0 (P0) and Postnatal day 30 (P30) embryos/fetuses from the pigs were used for this study. The results showed that KNJ develops earlier than TMJ. Only one mesenchymal condensate of KNJ is formed on E30, while two mesenchymal condensates of TMJ are present on E35. All structures of KNJ and TMJ were formed on E45. The growth plate of KNJ begins to develop on E45 and becomes more pronounced from E55 to P30. From E75 to E90, more and more vascular-rich cartilage canals form in the cartilage regions of both joints. The cartilaginous canal of the TMJ divides the condyle into sections along the longitudinal axis of the condyle. This arrangement of cartilaginous canal was not found in the KNJ. The chondrification of KNJ precedes that of TMJ. Ossification of the knee condyle occurs gradually from the middle to the periphery, while that of the TMJ occurs gradually from the base of the mandibular condyle. In the KNJ, the ossification of the articular condyle is evident from P0 to P30, and the growth plate is completely formed on P30. In the TMJ, the cartilage layer of condyle becomes thinner from P0 to P30. There is no growth plate formation in TMJ during its entire development. There is no growth plate formation in the TMJ throughout its development. The condyle may be the developmental center of the TMJ. The chondrocytes and hypertrophic chondrocytes of the growth plate are densely arranged. The condylar chondrocytes of TMJ are scattered, while the hypertrophic chondrocytes are arranged. Embryonic development of KNJ and TMJ in pigs is an important bridge for translating the results of rodent studies to medical applications.

Effect of fatigue on knee biomechanics during the sidestep cutting manoeuvre: A modelling approach.

Loading both lateral and medial compartments is crucial to understanding the effect of muscle fatigue during sidestep cutting. The present study investigated the changes in tibiofemoral contact forces in the medial and lateral compartments and the muscle force contributions during the sidestep-cutting manoeuvre after a handball-specific fatigue protocol. Twenty female handball athletes performed three trials of the sidestep-cutting manoeuvre before (baseline) and after the fatigue protocol. Motion capture and ground reaction forces were measured, and the data were processed in OpenSim. The variables were compared using statistical parametric mapping (SPM), with a significance level of p < 0.05. The results showed a decreased knee flexion angle during fatigue in the early stance phase. In addition, the post-fatigue analysis demonstrated significantly reduced forces in vasti muscles. Similarly, during fatigue, the SPM analysis showed decreased tibiofemoral contact forces in the vertical and anterior directions. Vertical force applied to both medial and lateral condyles demonstrated a significant reduction after the fatigue protocol. These results indicated that forces applied to the tibiofemoral joint were reduced following the fatigue protocol compared to the baseline values. However, no consistent evidence exists that fatigue increases the risk of knee injuries.

Dutch multidisciplinary guideline on anterior knee pain: Patellofemoral pain and patellar tendinopathy.

PURPOSE: The purpose of this study was to develop a multidisciplinary guideline for patellofemoral pain (PFP) and patellar tendinopathy (PT) to facilitate clinical decision-making in primary and secondary care. METHODS: A multidisciplinary expert panel identified questions in clinical decision-making. Based on a systematic literature search, the strength of the scientific evidence was determined according to the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method and the weight assigned to the considerations by the expert panel together determined the strength of the recommendations. RESULTS: After confirming PFP or PT as a clinical diagnosis, patients should start with exercise therapy. Additional conservative treatments are indicated only when exercise therapy does not result in clinically relevant changes after six (PFP) or 12 (PT) weeks. Pain medications should be reserved for cases of severe pain. The additional value of imaging assessments for PT is limited. Open surgery is reserved for very specific cases of nonresponders to exercise therapy and those requiring additional conservative treatments. Although the certainty of evidence regarding exercise therapy for PFP and PT had to be downgraded ('very low GRADE' and 'low GRADE'), the expert panel advocates its use as the primary treatment strategy. The panel further formulated weaker recommendations regarding additional conservative treatments, pain medications, imaging assessments and open surgery ('very low GRADE' to 'low GRADE' assessment or absence of scientific evidence). CONCLUSION: This guideline recommends starting with exercise therapy for PFP and PT. The recommendations facilitate clinical decision-making, and thereby optimizing treatment and preventing unnecessary burdens, risks and costs to patients and society. LEVEL OF EVIDENCE: Level V, clinical practice guideline.

Conversion to knee arthroplasty is more common after meniscectomy than meniscus repair in patients older than age 40.

PURPOSE: To describe rates of conversion to unicompartmental or total knee arthroplasty (KA) in patients over the age of 40 years (at initial surgery) after partial meniscectomy (ME) or meniscal repair (MR). METHODS: Patients over the age of 40 undergoing isolated ME or MR between 2016 and 2018 were extracted from a single healthcare provider database. Data on patient characteristics, type of initial surgery, number of returns to the operating room, as well as performed procedures, including conversion to KA, were recorded. Comparative group statistics as well as a Kaplan-Meier survival rate analysis were performed. RESULTS: A total of 3638 patients (47.8% female) were included, with 3520 (96.8%) undergoing ME and 118 (3.2%) MR. Overall, 378 (10.4%) patients returned to the OR at an average of 22.7 ± 17.3 months postoperatively. Conversion to KA was performed more frequently in patients after primary ME (n = 270, 7.7%) compared to those with MR (2.5%, n = 3, odds ratio [OR]: 3.2, p = 0.03). Compared to ME (2.3%, n = 82), two times as many patients undergoing MR returned for subsequent meniscus surgery (MR: 5.9%, n = 7, OR: 2.6, p = 0.02). Time from primary surgery to KA (ME: 22 ± 17 months, MR: 25 ± 15 months, p = 0.96) did not differ between the treatment groups. Survivorship was 95% for ME and 98.2% for MR after 24 months (p = 0.76) and 92.5% and 98.2% after 60 months (p = 0.07), respectively. CONCLUSION: The overall reoperation rate after meniscal surgery was 10.4% in patients over the age of 40 years. Patients treated with primary ME have over three times higher odds to undergo subsequent KA compared to those treated with MR. However, patients with primary MR have a higher rate of subsequent meniscus surgery compared to those undergoing primary ME. This information is important when considering and treating a patient over the age of 40 and meniscal injury. LEVEL OF EVIDENCE: Level III study.

Analysis of the Swedish Knee Ligament Register: Concomitant injuries, revision surgery and smoking render worse results.

PURPOSE: To analyse the 52,199 patients in the Swedish Knee Ligament Register (SKLR) preoperatively, and the patients reaching 5- and 10-year follow-ups who underwent anterior cruciate ligament reconstruction (ACLR), revision ACLR and ACLR on the contralateral side (CACLR). The main hypothesis was that patients undergoing revision ACLR would have worse patient-reported outcome measurements (PROMs) than the primary ACLR group at 10 years and that smoking and concomitant injuries would result in poorer outcomes for all groups. METHODS: Data from 2005 to 2021 were extracted from the SKLR. Only patients whose ACLR surgery was registered in the SKLR were included for revision ACLR and CACLR. The PROMs consist of the Knee injury and Osteoarthritis Outcome Score (KOOS) and the knee-specific PROM (EQ-5D-3L). PROMs were analysed as a whole and in subgroups based on sex, smoking, graft choice and concomitant injuries. RESULTS: Poorer KOOS were seen for revisions compared with primary ACLRs at both the 5- and 10-year follow-ups (p = 0.003). Smokers had significantly poorer KOOS than nonsmokers (p < 0.001) preoperatively in all groups, however only in the primary ACLR group at 5 and 10 years. At 10 years, patients who had undergone CACLR had lower KOOS than primary ACLRs (p = 0.03). Concomitant injuries resulted in statistically, significantly poorer KOOS for both primary ACLRs and CACLRs preoperatively and at the follow-ups. CONCLUSION: The PROMs for revision ACLRs have worse KOOS scores at 10 years compared with the primary ACLRs. The presence of concomitant meniscal or cartilage injuries at the time of ACLR or CACLR were associated with worse PROMs. LEVEL OF EVIDENCE: Level III.

Joint-line obliquity angle is significantly affected by hip abduction and adduction: A simulated analysis.

PURPOSE: Different methods for quantifying joint-line obliquity (JLO) have been described, including joint-line obliquity angle (JLOA), Mikulicz joint-line angle (MJLA) and medial proximal tibial angle (MPTA). The goal of the present study was to quantify the variation of JLOA based on the position of the hip. The hypothesis of our study is that JLO is significantly influenced by the abduction/adduction of the limb, unlike MJLA. METHODS: One hundred long-leg-weightbearing X-rays were used. At time 0 and after 30 days, two observers performed different measurements, including (1) distance between pubic symphysis and center of the femoral head, (2) distance between center of the femoral head and center of the ankle joint, (3) distance between center of the ankle and medial malleolus, (4) hip-knee-ankle angle, (5) MPTA, (6) lateral distal femoral angle, (7) joint-line congruency angle, (8) JLOA, (9) MJL and (10) angle between Mikulicz line and line perpendicular to the ground. The changes of the JLOA based on the position of the hip (abducted, neutral, bipedal stance adduction and monopodal stance adduction) were calculated with trigonometric formulas and with simulation on an orthopaedic planning digital software. RESULTS: The JLOA change between adducted and abducted positions was on average 12.8° (SD 0.9 mm). The MJL did not vary significantly based on hip position. CONCLUSIONS: The adduction/abduction of the lower limb has a considerable impact on JLOA. Methods like MJLA which are not affected by hip position should be preferred for JLO evaluation. LEVEL OF EVIDENCE: Diagnostic study, level III.

Functional knee brace use for 21 h leads to a longer duration to achieve peak vertical ground reaction forces and the removal of the brace after 17.5 h results in faster loading of the knee joint.

PURPOSE: To investigate the landing strategies used after discontinuing and continuing the use of a functional knee brace (FKB) while performing a drop jump. METHODS: Following published methodology and power analysis, 23 uninjured male athletes, mean age of 19.4 ± 3.0 years, performed seven tests, during three test conditions (nonbraced, braced and removed brace or continued brace use), over 6 days of 12 testing sessions (S) for a total of 38.5 h. Each subject was provided with a custom-fitted FKB. This study focuses on the single leg drop jump kinetics during S12 when subjects were randomly selected to remove the FKB after 17.5 h or continued use of FKB. The time to peak vertical ground reaction forces (PVGRF) and PVGRF were recorded on landing in eight trials. RESULTS: After brace removal, a significantly shorter mean time to PVGRF was recorded (9.4 ± 22.9 msec (3.9%), p = 0.005, 95% confidence interval (95% CI): -168.1, 36.1), while continued brace use required a nonsignificant (n.s.) longer mean duration to achieve PVGRF (19.4 ± 53.6 msec (8.9%), n.s., 95% CI: -49.7, 73.4). No significant mean PVGRF difference was found in brace removal (25.3 ± 65.8 N) and continued brace use (25.1 ± 23.0 N). CONCLUSION: Removal of FKB after 17.5 h of use led to a significantly shorter time to achieve PVGRF, while continued brace use for 21 h required a longer duration to achieve PVGRF, suggesting faster and slower knee joint loading, respectively. Understanding the concerns associated with the use of FKB and the kinetics of the knee joint will assist clinicians in counselling athletes about the risks and benefits of using an FKB. LEVEL OF EVIDENCE: Level II.

CPAK classification detect the real knee joint apex position in less than half of the knees.

PURPOSE: Accurate assessment of the knee joint line is essential for surgeries involving the knee. The knee joint line obliquity (KJLO) is a radiological measurement that evaluates the position of the knee joint relative to the ground and is frequently used in preoperative planning and clinical follow-up. On the other hand, coronal plane alignment of the knee (CPAK) classifications assesses the joint line as the summation of the medial proximal tibial angle (MPTA) and mechanical lateral distal femoral angle (mLDFA). The purpose of this study is to determine the concordance of these two measurement techniques. METHODS: This cross-sectional study evaluated the long-leg standing radiographs (LSRs) of 164 healthy knees. The extremity KJLO and CPAK classification JLO were measured twice by two observers at 8-week intervals. The knee joint line apex positions (proximal, neutral and distal) of the two measurement techniques are compared (concordance or discordant). The intraobserver and interobserver reliability were examined using the intraclass correlation coefficient (ICC). Possible causes of the discordant were evaluated with univariate and multivariate logistic regression analysis. RESULTS: CPAK classification detected the KJLO apex position in 70 extremities (42.7%) only. Subgroups CPAK JLO detected 13.6% of the proximal apex, 20.4% of the neutral, and 90.7% of the distal apex (p < 0.01). Upon multivariate logistic regression analysis, the variable KJLO apex position (proximal, neutral vs. distal, odds ratio (OR) = 10.291, 95% confidence interval [CI] = 2.225-25.656, and (p < 0.01) was determined as a risk factor for discordant. CONCLUSION: The CPAK JLO measurement technique can be misleading in defining the KJLO apex position and the concordance between them is less than 50%. It has a high tendency to misleadingly predict proximal and neutral apex positions, which can potentially have negative implications for assessing the joint line. LEVEL OF EVIDENCE: Level I.