Aims. Periprosthetic fractures (PPFs) around the knee are challenging injuries. This study aims to describe the characteristics of knee PPFs and the impact of patient demographics, fracture types, and management modalities on in-hospital mortality. Methods. Using a multicentre study design, independent of registry data, we included adult patients sustaining a PPF around a knee arthroplasty between 1 January 2010 and 31 December 2019. Univariate, then multivariable, logistic regression analyses were performed to study the impact of patient, fracture, and treatment on mortality. Results. Out of a total of 1,667 patients in the PPF study database, 420 patients were included. The in-hospital mortality rate was 6.4%. Multivariable analyses suggested that American Society of Anesthesiologists (ASA) grade, history of peripheral vascular disease (PVD), history of rheumatic disease, fracture around a loose implant, and cerebrovascular accident (CVA) during hospital stay were each independently associated with mortality. Each point increase in ASA grade independently correlated with a four-fold greater mortality risk (odds ratio (OR) 4.1 (95% confidence interval (CI) 1.19 to 14.06); p = 0.026). Patients with PVD have a nine-fold increase in mortality risk (OR 9.1 (95% CI 1.25 to 66.47); p = 0.030) and patients with rheumatic disease have a 6.8-fold increase in mortality risk (OR 6.8 (95% CI 1.32 to 34.68); p = 0.022). Patients with a fracture around a loose implant (Unified Classification System (UCS) B2) have a 20-fold increase in mortality, compared to UCS A1 (OR 20.9 (95% CI 1.61 to 271.38); p = 0.020). Mode of management was not a significant predictor of mortality. Patients managed with revision arthroplasty had a significantly longer length of stay (median 16 days; p = 0.029) and higher rates of return to theatre, compared to patients treated nonoperatively or with fixation. Conclusion. The mortality rate in PPFs around the knee is similar to that for native distal femur and neck of femur fragility fractures. Patients with certain modifiable risk factors should be optimized. A national PPF database and standardized management guidelines are currently required to understand these complex injuries and to improve patient outcomes. Cite this article: Bone Joint J 2024;106-B(2):158–165

Aims. The aim of this study was to determine the prevalence and impact of tourniquet use in patients undergoing limb salvage surgery with endoprosthetic reconstruction for a tumour around the knee. Methods. We retrieved data from the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) trial; specifically, differences in baseline characteristics, surgical details, and postoperative functional outcomes between patients who had undergone surgery under tourniquet and those who had not. A linear regression model was created to evaluate the impact of tourniquet use on postoperative Toronto Extremity Salvage Scores (TESSs) while controlling for confounding variables. A negative-binomial regression model was constructed to explore predictors of postoperative length of stay (LOS). Results. Of the 604 patients enrolled in the PARITY trial, 421 had tumours around the knee joint, of whom 225 (53%) underwent surgery under tourniquet. The tourniquet group was younger (p = 0.014), more likely to undergo surgery for a tumour of the tibia, and had shorter operating times by a mean of 50 minutes (95% confidence interval 30 to 72; p < 0.001). The adjusted linear regression model found that the use of a tourniquet, a shorter operating time, and a higher baseline TESS independently predicted better function at both three- and six-month follow-up. The negative-binomial regression model showed that tourniquet use, shorter operating time, younger age, and intraoperative tranexamic acid administration independently predicted a shorter LOS in hospital. Conclusion. The results of this study show that in patients undergoing resection of a tumour around the knee and endoprosthetic reconstruction, the use of an intraoperative tourniquet is associated with a shorter operating time, a reduced length of stay in hospital, and a better early functional outcome. Cite this article: Bone Joint J 2022;104-B(10):1168–1173

Aims. Intra-articular (IA) tumours around the knee are treated with extra-articular (EA) resection, which is associated with poor functional outcomes. We aim to evaluate the accuracy of MRI in predicting IA involvement around the knee. Methods. We identified 63 cases of high-grade sarcomas in or around the distal femur that underwent an EA resection from a prospectively maintained database (January 1996 to April 2020). Suspicion of IA disease was noted in 52 cases, six had IA pathological fracture, two had an effusion, two had prior surgical intervention (curettage/IA intervention), and one had an osseous metastasis in the proximal tibia. To ascertain validity, two musculoskeletal radiologists (R1, R2) reviewed the preoperative imaging (MRI) of 63 consecutive cases on two occasions six weeks apart. The radiological criteria for IA disease comprised evidence of tumour extension within the suprapatellar pouch, intercondylar notch, extension along medial/lateral retinaculum, and presence of IA fracture. The radiological predictions were then confirmed with the final histopathology of the resected specimens. Results. The resection histology revealed 23 cases (36.5%) showing IA disease involvement compared with 40 cases without (62%). The intraobserver variability of R1 was 0.85 (p < 0.001) compared to R2 with κ = 0.21 (p = 0.007). The interobserver variability was κ = 0.264 (p = 0.003). Knee effusion was found to be the most sensitive indicator of IA involvement, with a sensitivity of 91.3% but specificity of only 35%. However, when combined with a pathological fracture, this rose to 97.5% and 100% when disease was visible in Hoffa’s fat pad. Conclusion. MRI imaging can sometimes overestimate IA joint involvement and needs to be correlated with clinical signs. In the light of our findings, we would recommend EA resections when imaging shows effusion combined with either disease in Hoffa’s fat pad or retinaculum, or pathological fractures. Cite this article: Bone Joint J 2023;105-B(6):696–701

Aims. In cases of severe periprosthetic joint infection (PJI) of the knee, salvage procedures such as knee arthrodesis (KA) or above-knee amputation (AKA) must be considered. As both treatments result in limitations in quality of life (QoL), we aimed to compare outcomes and factors influencing complication rates, mortality, and mobility. Methods. Patients with PJI of the knee and subsequent KA or AKA between June 2011 and May 2021 were included. Demographic data, comorbidities, and patient history were analyzed. Functional outcomes and QoL were prospectively assessed in both groups with additional treatment-specific scores after AKA. Outcomes, complications, and mortality were evaluated. Results. A total of 98 patients were included, 52 treated with arthrodesis and 47 with AKA. The mean number of revision surgeries between primary arthroplasty and arthrodesis or AKA was 7.85 (SD 5.39). Mean follow-up was 77.7 months (SD 30.9), with a minimum follow-up of two years. Complications requiring further revision surgery occurred in 11.5% of patients after arthrodesis and in 37.0% of AKA patients. Positive intraoperative tissue cultures obtained during AKA was significantly associated with the risk of further surgical revision. Two-year mortality rate of arthrodesis was significantly lower compared to AKA (3.8% vs 28.3%), with age as an independent risk factor in the AKA group. Functional outcomes and QoL were better after arthrodesis compared to AKA. Neuropathic pain was reported by 19 patients after AKA, and only 45.7% of patients were fitted or were intended to be fitted with a prosthesis. One-year infection-free survival after arthrodesis was 88.5%, compared to 78.5% after AKA. Conclusion. Above-knee amputation in PJI results in high complication and mortality rates and poorer functional outcome compared to arthrodesis. Mortality rates after AKA depend on patient age and mobility, with most patients not able to be fitted with a prosthesis. Therefore, arthrodesis should be preferred whenever possible if salvage procedures are indicated. Cite this article: Bone Joint J 2024;106-B(7):669–679

Aims. In countries with social healthcare systems, such as Canada, patients may experience long wait times and a decline in their health status prior to their operation. The aim of this study is to explore the association between long preoperative wait times (WT) and acute hospital length of stay (LoS) for primary arthroplasty of the knee and hip. Methods. The study population was obtained from the provincial Patient Access Registry Nova Scotia (PARNS) and the Canadian national hospital Discharge Access Database (DAD). We included primary total knee and hip arthroplasties (TKA, THA) between 2011 and 2017. Patients waiting longer than the recommended 180 days Canadian national standard were compared to patients waiting equal or less than the standard WT. The primary outcome measure was acute LoS postoperatively. Secondarily, patient demographics, comorbidities, and perioperative parameters were correlated with LoS with multivariate regression. Results. A total of 11,833 TKAs and 6,627 THAs were included in the study. Mean WT for TKA was 348 days (1 to 3,605) with mean LoS of 3.6 days (1 to 98). Mean WT for THA was 267 days (1 to 2,015) with mean LoS of 4.0 days (1 to 143). There was a significant increase in mean LoS for TKA waiting longer than 180 days (2.5% (SE 1.1); p = 0.028). There was no significant association for THA. Age, sex, surgical year, admittance from home, rural residence, household income, hospital facility, the need for blood transfusion, and comorbidities were all found to influence LoS. Conclusion. Surgical WT longer than 180 days resulted in increased acute LoS for primary TKA. Meeting a shorter WT target may be cost-saving in a social healthcare system by having shorter LoS. Cite this article: Bone Jt Open 2021;2(8):679–684

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Implantation of ultra-purified alginate (UPAL) gel is safe and effective in animal osteochondral defect models. This study aimed to examine the applicability of UPAL gel implantation to acellular therapy in humans with cartilage injury.

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Classifying trochlear dysplasia (TD) is useful to determine the treatment options for patients suffering from patellofemoral instability (PFI). There is no consensus on which classification system is more reliable and reproducible for the purpose of guiding clinicians’ management of PFI. There are also concerns about the validity of the Dejour Classification (DJC), which is the most widely used classification for TD, having only a fair reliability score. The Oswestry-Bristol Classification (OBC) is a recently proposed system of classification of TD, and the authors report a fair-to-good interobserver agreement and good-to-excellent intraobserver agreement in the assessment of TD. The aim of this study was to compare the reliability and reproducibility of these two classifications.

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The extended wait that most patients are now experiencing for hip and knee arthroplasty has raised questions about whether reliance on waiting time as the primary driver for prioritization is ethical, and if other additional factors should be included in determining surgical priority. Our Prioritization of THose aWaiting hip and knee ArthroplastY (PATHWAY) project will explore which perioperative factors are important to consider when prioritizing those on the waiting list for hip and knee arthroplasty, and how these factors should be weighted. The final product will include a weighted benefit score that can be used to aid in surgical prioritization for those awaiting elective primary hip and knee arthroplasty.

The restoration of knee alignment is an important goal during total knee arthroplasty (TKA). In the past surgeons aimed to restore neutral limb alignment during surgery. However, previous studies have demonstrated alignment to be dynamic, varying depending on the position of the limb and the degree of weight-bearing, and between patients. We used a validated computer navigation system to measure the femorotibial mechanical angle (FTMA) in 264 knees in 77 male and 55 female healthy volunteers aged 18 to 35 years (mean 26.2). We found the mean supine alignment to be a varus angle of 1.2° (standard deviation (. sd. ) 4), with few patients having neutral alignment. FTMA differs significantly between males and females (with a mean varus of 1.7° (. sd. 4) and 0.4° (. sd. 3.9), respectively; p = 0.008). It changes significantly with posture, the knee hyperextending by a mean of 5.6°, and coronal plane alignment becoming more varus by 2.2° (. sd. 3.6) on standing compared with supine. Knee alignment is different in different individuals and is dynamic in nature, changing with different postures. This may have implications for the assessment of alignment in TKA, which is achieved in non-weight-bearing conditions and which may not represent the situation observed during weight-bearing. Cite this article: Bone Joint J 2015; 97-B:498–502

The aim of this study was to assess the effect of injecting genetically engineered chondrocytes expressing transforming growth factor beta 1 (TGF-β1) into the knees of patients with osteoarthritis. We assessed the resultant function, pain and quality of life. . A total of 54 patients (20 men, 34 women) who had a mean age of 58 years (50 to 66) were blinded and randomised (1:1) to receive a single injection of the active treatment or a placebo. We assessed post-treatment function, pain severity, physical function, quality of life and the incidence of treatment-associated adverse events. Patients were followed at four, 12 and 24 weeks after injection. At final follow-up the treatment group had a significantly greater improvement in the mean International Knee Documentation Committee score than the placebo group (16 points; -18 to 49, vs 8 points; -4 to 37, respectively; p = 0.03). The treatment group also had a significantly improved mean visual analogue score at final follow-up (-25; -85 to 34, vs -11 points; -51 to 25, respectively; p = 0.032). Both cohorts showed an improvement in Western Ontario and McMaster Osteoarthritis Index and Knee Injury and Osteoarthritis Outcome Scores, but these differences were not statistically significant. One patient had an anaphylactic reaction to the preservation medium, but recovered within 24 hours. All other adverse events were localised and resolved without further action. . This technique may result in improved clinical outcomes, with the aim of slowing the degenerative process, leading to improvements in pain and function. However, imaging and direct observational studies are needed to verify cartilage regeneration. Nevertheless, this study provided a sufficient basis to proceed to further clinical testing. Cite this article: Bone Joint J 2015;97-B:924–32

Arthroscopy of the knee is one of the most commonly performed orthopaedic procedures worldwide. Large-volume outcome data have not previously been available for English NHS patients. Prospectively collected admissions data, routinely collected on every English NHS patient, were analysed to determine the rates of complications within 30 days (including re-operation and re-admission), 90-day symptomatic venous thromboembolism and all-cause mortality. There were 301 701 operations performed between 2005 and 2010 – an annual incidence of 9.9 per 10 000 English population. Of these, 16 552 (6%) underwent ligament reconstruction and 106 793 (35%) underwent meniscal surgery. The 30-day re-admission rate was 0.64% (1662) and 30-day wound complication rate was 0.26% (677). The overall 30-day re-operation rate was 0.40% (1033) and the 90-day pulmonary embolism rate was 0.08% (230), of which six patients died. 90-day mortality was 0.02% (47). Age < 40 years, male gender and ligament reconstruction were significantly associated with an increased rate of 30-day re-admission and unplanned re-operation. In addition, a significant increase in 30-day admission rates were seen with Charlson comorbidity scores of 1 (p = 0.037) and ≥ 2 (p <  0.001) compared with scores of 0, and medium volume units compared with high volume units (p < 0.001). Complications following arthroscopy of the knee are rare. It is a safe procedure, which in the majority of cases is performed as day case surgery. These data can be used for quality benchmarking, in terms of consent, consultant re-validation and individual unit performance

Aims. We investigated changes in the axial alignment of the ipsilateral hip and knee after total hip arthroplasty (THA). . Patients and Methods. We reviewed 152 patients undergoing primary THA (163 hips; 22 hips in men, 141 hips in women) without a pre-operative flexion contracture. The mean age was 64 years (30 to 88). The diagnosis was osteoarthritis (OA) in 151 hips (primary in 18 hips, and secondary to dysplasia in 133) and non-OA in 12 hips. A posterolateral approach with repair of the external rotators was used in 134 hips and an anterior approach in 29 hips. We measured changes in leg length and offset on radiographs, and femoral anteversion, internal rotation of the hip and lateral patellar tilt on CT scans, pre- and post-operatively. . Results. The mean internal rotation increased by 11° (-15° to 46°) and was associated with underlying disease (OA), pre-operative range of internal rotation, gender, surgical approach, leg lengthening, and change of femoral anteversion (adjusted R. 2. : 0.253, p < 0.001). The mean lateral patellar tilt increased by 4° (-5° to 14°) and was associated with age, leg lengthening, and increment of hip internal rotation (adjusted R. 2. : 0.193, p < 0.001). Conclusion. Both internal rotation of the hip at rest and lateral patellar tilt are increased after THA. Changes in rotation after THA may affect gait, daily activities, the rate of dislocation of the hip, and ipsilateral knee pain. Take home message: Internal rotation of the hip at rest and lateral patellar tilt increase after THA. Cite this article: Bone Joint J 2016;98-B:349–58

Aims. Increasing demand for total hip and knee arthroplasty (THA/TKA) and associated follow-up has placed huge demands on orthopaedic services. Feasible follow-up mechanisms are therefore essential. . Methods. We conducted an audit of clinical follow-up decision-making for THA/TKA based on questionnaire/radiograph review compared with local practice of Arthroplasty Care Practitioner (ACP)-led outpatient follow-up. In all 599 patients attending an ACP-led THA/TKA follow-up clinic had a pelvic/knee radiograph, completed a pain/function questionnaire and were reviewed by an ACP. An experienced orthopaedic surgeon reviewed the same radiographs and questionnaires, without patient contact or knowledge of the ACP’s decision. Each pathway classified patients into: urgent review, annual monitoring, routine follow-up or discharge. . Results. In total, 401 hip and 198 knee patients were included. There was substantial agreement between the ACP and surgeon for both hip (kappa = 0.69, 95% confidence interval (CI) 0.62 to 0.76) and knee (kappa = 0.81, 95% CI 0.74 to 0.88). Positive agreement was very high for discharge and routine follow-up; however the ACP was more likely to select annual monitoring and the surgeon urgent review. . Discussion. Review of the questionnaire/radiograph together identified all patients in need of increased surveillance, with good agreement for on-going patient management. However, review of the radiograph or questionnaire alone missed some patients with potential problems. A radiograph in conjunction with a questionnaire as a review may represent a cost effective THA/TKA follow-up mechanism. Take home message: A questionnaire and radiograph-based remote review may represent a cost-effective total joint arthroplasty follow-up mechanism; thereby reducing the considerable burden that follow-up currently places on the NHS. Cite this article: Bone Joint J 2016;98-B:201–8

Aims. The aim of this study was to describe and compare joint-specific and generic health-related quality of life outcomes of the first versus second knee in patients undergoing staged bilateral total knee arthroplasty (BTKA) for osteoarthritis. Methods. This retrospective cohort study used Australian national arthroplasty registry data from January 2013 to January 2021 to identify participants who underwent elective staged BTKA with six to 24 months between procedures. The primary outcome was Oxford Knee Score (OKS) at six months postoperatively for the first TKA compared to the second TKA, adjusted for age and sex. Secondary outcomes compared six-month EuroQol five-dimension five-level (EQ-5D-5L) domain scores, EQ-5D index scores, and the EQ visual analogue scale (EQ-VAS) between knees at six months postoperatively. Results. The cohort included 635 participants (1,270 primary procedures). Preoperative scores were worse in the first knee compared to the second for all instruments; however, comparing the first knee at six months postoperatively with the second knee at six months postoperatively, the mean between-knee difference was minimal for OKS (-0.8 points; 95% confidence interval (CI) -1.4 to -0.2), EQ-VAS (3.3; 95% CI 1.9 to 4.7), and EQ-5D index (0.09 points; 95% CI 0.07 to 0.12). Outcomes for the EQ-5D-5L domains ‘mobility’, ‘usual activities’, and ‘pain/discomfort’ were better following the second TKA. Conclusion. At six months postoperatively, there were no clinically meaningful differences between the first and second TKA in either the joint-specific or overall generic health-related quality of life outcomes. However, individual domain scores assessing mobility, pain, and usual activities were notably higher after the second TKA, likely reflecting the cumulative improvement in quality of life after both knees have been replaced. Cite this article: Bone Jt Open 2024;5(3):202–209

Abstract. Introduction. Knee braces are limited to providing passive support. There is currently no brace available providing both continuous monitoring and active robot-assisted movements of the knee joint. This project aimed to develop a wearable intelligent motorised robotic knee brace to support and monitor rehabilitation for a range of knee conditions including post-surgical rehabilitation. This brace can be used at home providing ambulatory continuous passive movement obviating the need for hospital admissions. Methodology. A wearable sensing system monitoring knee range of motion was developed to provide remote feedback to clinicians and real-time guidance for patients. A prototype of an exoskeleton providing dynamic motion assistance was developed to help patients complete their exercise goals and strengthen their muscles. The accuracy and reliability of those functions were validated in human participants during exercises including knee flexion/extension (FE) in bed and in chair, sit-to-stand and stand-to-sit. Results. The knee FE measurement from the sensing system showed high accuracy (correlation coefficient of 0.99°) in human participants. The real-time FE data during exercises showed that the desired exoskeleton rotation fitted well with the participant's knee rotation. This indicated the exoskeleton could coordinate with the participant's knee motion by providing consistent motion assistance. The development of user interfaces to provide feedback is currently underway. Conclusion. A wearable robotic knee brace to monitor and support knee rehabilitation exercises was successfully developed. Further development of this device with the use of artificial intelligence has the potential to aid patient rehabilitation in a variety of knee conditions

Several emerging reports suggest an important involvement of the hindfoot alignment in the outcome of knee osteotomy. At present, studies lack a comprehensive overview. Therefore, we aimed to systematically review all biomechanical and clinical studies investigating the role of the hindfoot alignment in the setting of osteotomies around the knee. A systematic literature search was conducted on multiple databases combining “knee osteotomy” and “hindfoot/ankle alignment” search terms. Articles were screened and included according to the PRISMA guidelines. A quality assessment was conducted using the Quality Appraisal for Cadaveric Studies (QUACS) - and modified methodologic index for non-randomized studies (MINORS) scales. Three cadaveric, fourteen retrospective cohort and two case-control studies were eligible for review. Biomechanical hindfoot characteristics were positively affected (n=4), except in rigid subtalar joint (n=1) or talar tilt (n=1) deformity. Patient symptoms and/or radiographic alignment at the level of the hindfoot did also improve after knee osteotomy (n=13), except in case of a small pre-operative lateral distal tibia- and hip knee ankle (HKA) angulation or in case of a large HKA correction (>14.5°). Additionally, a pre-existent hindfoot deformity (>15.9°) was associated with undercorrection of lower limb alignment following knee osteotomy. The mean QUACS score was 61.3% (range: 46–69%) and mean MINORS score was 9.2 out of 16 (range 6–12) for non-comparative and 16.5 out of 24 (range 15–18) for comparative studies. Osteotomies performed to correct knee deformity have also an impact on biomechanical and clinical outcomes of the hindfoot. In general, these are reported to be beneficial, but several parameters were identified that are associated with newly onset – or deterioration of hindfoot symptoms following knee osteotomy. Further prospective studies are warranted to assess how diagnostic and therapeutic algorithms based on the identified criteria could be implemented to optimize the overall outcome of knee osteotomy. Remark: Aline Van Oevelen and Arne Burssens contributed equally to this work

Individuals with multi-compartment knee osteoarthritis (KOA) frequently experience challenges in activities of daily living (ADL) such as stair ambulation. The Levitation “Tri-Compartment Offloader” (TCO) knee brace was designed to reduce pain in individuals with multicompartment KOA. This brace uses novel spring technology to reduce tibiofemoral and patellofemoral forces via reduced quadriceps forces. Information on brace utility during stair ambulation is limited. This study evaluated the effect of the TCO during stair descent in patients with multicompartment KOA by assessing knee flexion moments (KFM), quadriceps activity and pain. Nine participants (6 male, age 61.4±8.1 yrs; BMI 30.4±4.0 kg/m2) were tested following informed consent. Participants had medial tibiofemoral and patellofemoral OA (Kellgren-Lawrence grades two to four) diagnosed by an orthopaedic surgeon. Joint kinetics and muscle activity were evaluated during stair descent to compare three bracing conditions: 1) without brace (OFF); 2) brace in low power (LOW); and 3) brace in high power (HIGH). The brace spring engages from 60° to 120° and 15° to 120° knee flexion in LOW and HIGH, respectively. Individual brace size and fit were adjusted by a trained researcher. Participants performed three trials of step-over-step stair descent for each bracing condition. Three-dimensional kinematics were acquired using an 8-camera motion capture system. Forty-one spherical reflective markers were attached to the skin (on each leg and pelvis segment) and 8 markers on the brace. Ground reaction forces and surface EMG from the vastus medialis (VM) and vastus lateralis (VL) were collected for the braced leg. Participants rated knee pain intensity performing the task following each bracing condition on a 10cm Visual Analog Scale ranging from “no pain” (0) to “worst imaginable pain” (100). Resultant brace and knee flexion angles and KFM were analysed during stair contact for the braced leg. The brace moment was determined using brace torque-angle curves and was subtracted from the calculated KFM. Resultant moments were normalized to bodyweight and height. Peak KFMs were calculated for the loading response (Peak1) and push-off (Peak2) phases of support. EMG signals were normalized and analysed during stair contact using wavelet analysis. Signal intensities were summed across wavelets and time to determine muscle power. Results were averaged across all 3 trials for each participant. Paired T-tests were used to determine differences between bracing conditions with a Bonferroni adjustment for multiple comparisons (α=0.025). Peak KFM was significantly lower compared to OFF with the brace worn in HIGH during the push-off phase (p Table 1: Average peak knee flexion moments, quadriceps muscle power and knee pain during stair descent in 3 brace conditions (n=9). Quadriceps activity, knee flexion moments and pain were significantly reduced with TCO brace wear during stair descent in KOA patients. These findings suggest that the TCO assists the quadriceps to reduce KFM and knee pain during stair descent. This is the first biomechanical evidence to support use of the TCO to reduce pain during an ADL that produces especially high knee forces and flexion moments. For any figures or tables, please contact the authors directly

Aim. The primary endpoint of this study is to characterize the progression of bone defects at the femoral and tibial side in patients who sustained PJI of the knee that underwent two-stage revision with spacer implantation. In addition, we want to analyze the differences between functional moulded and hand-made spacers. Methods. A retrospective analysis of patients that underwent two-stage revision due to PJI of the knee between January 2014 and December 2021 at our institution. Diagnosis of infection was based on the criteria of the Muscoloskeletal Infection Society. The bone defect evaluation was performed intraoperatively based on the AORI classification. The basal evaluation was performed at the time the resection arthroplasty and spacer implantation surgery. The final evaluation was performed at the second-stage surgery, at the time of spacer removal and revision implant positioning. The differences between groups were characterized by using T-test student for continuous variables, and by using chi-square for categorical variables. A p-value < 0.05 was defined as significant. Results. Complete data of 37 two-stage TKAs revision were included in the study. An articulating moulded functional spacer was used in 14 (35.9%) cases, while a hand-made spacer was used in 23 (58.9%) cases. The average length of interval period (excluding the time for patients that retained the spacer) was 146.6 days. A bone defects progression based on the AORI classification was documented in 24 cases at the femoral side (61.6%), a bone defect progression was documented in 17 cases at the tibial side (43.6%), and a bone defect at both sides was documented in 13 cases (33.3%). A statistically significant greater bone defect progression at the tibial side was observed when hand-made spacers were used. A complication during the interval period was reported in five cases (12.8%) and postoperative complication was reported in 9 cases (23.1%). Conclusions. When comparing patients in which a functional articulating spacer was used, with patients in which static spacer was used, we reported a statistically significant reduced bone defect progression during the interval period at the femoral side only when moulded spacers were used. We observed a higher incidence of bone defect progression also at the tibial and both sides when hand-made spacers were used. This is the first study that documented the bone defect progression during two-stage revision of the knee, the results observed in this study are very encouraging

Abstract. Introduction. MRI scanning is the establish method of defining intra- and extra-articular diagnoses of patients with non-arthritic knee problems. Discrepancies in reporting have been noted in previous historic studies and anecdotally. The aim of this study was to analyse the reporting of intra-articular pathology and discrepancies in knee MRI reports by two clinician groups, consultant radiologists and consultant knee surgeons in a district hospital setting. Methods. A retrospective case-controlled cohort study was conducted using data collected from an outpatient physiotherapy-led knee clinic. Seventy-four patients in the cohort were referred for an MRI scan of their knee(s) following a clinical examination and history. MRI reports from both the consultant knee surgeon and the radiologist were entered into a database with other clinical details. Reports were analysed to determine number of diagnoses and degree of agreement. Each report was deemed to either completely agree, completely disagree or partially agree. Results. 87 knees were scanned in total. Of the 87 reports, 14% (n=12) completely agreed. 45% of the reports (n=39) partially agreed and 41% (n=36) completely disagreed. Of the reports which partially agreed 79% (n=31) had a percentage agreement of ≤ 50%. Conclusions. This study reveals major discrepancies in knee MRI reporting by two clinician groups. This has greatest clinical impact on non-surgical clinicians and those with limited MRI reviewing experience who are reliant on reports to describe diagnoses to patients and determining management plans. More research is required to determine the reasons for these differences and measures to mitigate them

We aim to determine the differences in lower limb joint kinematics during the golf swing of patients who had undergone Total Knee Arthroplasty (TKA) and a control group of native knee golfers. A case-control study was undertaken with ten golfers who had undergone TKA (cruciate retaining single radius implant) and five age and matched golfers with native knees. Each golfer performed five swings with a driver whilst being recorded at 200Hz by a ten-camera motion capture system. Knee and hip three-dimensional joint angles (JA) and joint angular velocities (JAV) were calculated and statistically compared between the groups at six swing events. The only significant differences in knee joint kinematics between TKA and control groups was a lower external rotation JA in the left knee during the backswing (p=0.010). There was no significant difference in knee JAV between the groups. Both hips demonstrated significantly (p=0.023 for left and p=0.037 for right) lower flexion in the TKA group during the takeaway swing event, and there was lower internal rotation in the backswing and greater external rotation in the downswing of the right hip. There was also slower left hip extension JAV in the downswing. Normal knee kinematics were observed during the golf swing following TKA, with the exception of reduced external rotation in the left knee during the back swing and the right during the down swing. The differences demonstrated in the hip motion indicate that they may make compensatory movements to adjust to the reduced external rotation demonstrated in the knee