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

Aims. The aim of this study was to investigate the rate of revision for distal femoral arthroplasty (DFA) performed as a primary procedure for native knee fractures using data from the Australian Orthopaedic Association National Joint Arthroplasty Registry (AOANJRR). Methods. Data from the AOANJRR were obtained for DFA performed as primary procedures for native knee fractures from 1 September 1999 to 31 December 2020. Pathological fractures and revision for failed internal fixation were excluded. The five prostheses identified were the Global Modular Arthroplasty System, the Modular Arthroplasty System, the Modular Universal Tumour And Revision System, the Orthopaedic Salvage System, and the Segmental System. Patient demographic data (age, sex, and American Society of Anesthesiologists grade) were obtained, where available. Kaplan-Meier estimates of survival were used to determine the rate of revision, and the reasons for revision and mortality data were examined. Results. The AOANJRR identified 153 primary DFAs performed for native knee fractures in 151 patients during the study period, with 63.3% of these (n = 97) performed within the last five years. The median follow-up was 2.1 years (interquartile range 0.8 to 4.4). The patient population was 84.8% female (n = 128), with a mean age of 76.1 years (SD 11.9). The cumulative percent revision rate at three years was 10%. The most common reason for revision was loosening, followed by infection. Patient survival at one year was 87.5%, decreasing to 72.8% at three years postoperatively. Conclusion. The use of DFA to treat native knee fractures is increasing, with 63.3% of cases performed within the last five years. While long-term data are not available, the results of this study suggest that DFA may be a reasonable option for elderly patients with native knee fractures where fixation is not feasible, or for whom prolonged non-weightbearing may be detrimental. Cite this article: Bone Joint J 2022;104-B(7):894–901

Introduction. To determine if elite athletes can return to professional sport after MCL or posterolateral (PLC) reconstruction using LARS ligaments. The secondary aims are to demonstrate the safety and efficacy of LARS by reporting sport longevity, subsequent surgeries, and complications. Methods. A retrospective review of all extra-articular knee ligament reconstructions, utilising a LARS synthetic ligament, by 3 sports knee surgeons between 2013 and 2020 was undertaken. All elite athletes aged over 16 years and a minimum of 2 years post reconstruction were included. No LARS were used for ACL reconstructions, and they were excluded if a LARS ligament was used for a PCL reconstruction. Return to play (RTP) was defined as competing at professional level or national/ international level in amateur sport. Results. Sixty-four (84.2%) MCL reconstructions and 12 (15.8%) PLC reconstructions were included. 52 (68.4%) underwent concomitant autograft cruciate(s) reconstruction including 6 (7.8%) bicruciate reconstructions. The mean age was 25.1 years (SD +/− 4.50). 35 (46.1%) were footballers and 35 (46.1%) were rugby players. Sixty-seven athletes (88.2%) returned to elite sport, 7 (9.2%) did not RTP and RTP status was unknown for 2 (2.6%) (Figure 1). 65 out of 67 (97.0%) RTP at the same/higher Tegner level. 56 (83.6%) and 20 (57.1%) were still playing at 2- and 5-years post-surgery Six (7.9%) players required further surgery due to irritation from the metal fixation implants. One had an inflammation adjacent to the synthetic material at the femoral end and the other cases involved the tibial staples. All six cases were able to RTP. One athlete, following bicruciate /MCL surgery had the LARS removed due to laxity. There was one MCL re-rupture, sustained while jumping, 4 years after returning to football. Conclusions. Utilising LARS in extra-articular knee ligament reconstructions allows 88.2% of athletes with a variety of knee ligament injuries to return to elite sport. The results compare well regarding RTP, complication, and revision rates with the published evidence for other types of MCL and PLC grafts. This, coupled with 57% of athletes still playing 5 years post-surgery suggests the LARS is safe and effective in these cases. For any figures or tables, please contact authors directly

Objectives. Congenital cruciate ligament deficiency is a rare condition that may occur in isolation or in association with longitudinal limb deficiencies such as fibular hemimelia or proximal femoral focal deficiency. Often anomalies of the menisci and their attachments can be very abnormal and impact on surgical management by standard techniques. Arthroscopic surgical knee reconstruction is undertaken to improve symptomatic instability and/or to stabilise and protect the knee for future planned limb lengthening surgery. The aim of this study is to evaluate the arthroscopic findings of patients undergoing surgery for congenital cruciate ligament deficiency, and specifically to determine the frequency and types of meniscal anatomical variations seen in these cases. Methods. Patients undergoing surgery for congenital cruciate ligament deficiency were identified from a prospectively collated database. Diagnosis was confirmed through review of the clinical notes and imaging. Operative notes and 4K saved arthroscopic images and video recordings for these cases were reviewed. Results. Over a six-year period (July 2017 – September 2023), 42 patients underwent surgery for congenital ligament deficiency and tibiofemoral instability (45 surgical episodes). Median age of patients at time of surgery was 10 years (range 4 – 17 years). The most frequent diagnosis was congenital longitudinal limb deficiency syndromes in 27 cases, with the most frequent being fibular hemimelia. Isolated congenital ligament deficiency without any other associated extra-articular manifestations occurred in 11 cases. Absence of meniscal root attachments or hypertrophy of meniscofemoral ligaments acting as ‘pseudo-cruciates’ were seen in over 25% of patients. In isolated ACL deficiency these were injured causing onset of instability symptoms and pain following trauma. Often these abnormal structures required addressing to allow surgical reconstruction. Conclusions. Our findings demonstrate that there are often meniscal variations seen in association with congenital absence or hypoplasia of the cruciate ligaments. In these patients hypertrophied meniscofemoral ligaments may act as cruciate-like structures and play a role in providing a degree of sagittal plane stability to the knee. However, when the knee becomes unstable to the point that cruciate ligament reconstruction is indicated, these meniscal variants may often require stabilisation using complex meniscal root repair techniques or variations to standard cruciate ligament reconstruction techniques to accommodate the variant anatomy

Introduction. The knee is the most commonly injured joint in sporting accidents, leading to substantial disability, time off work and morbidity (1). Treatment and assessment vary around the UK (2), whilst there remains a limited number of high-quality randomised controlled trials assessing first time, acute soft tissue knee injuries (3,4). As the clinical and financial burden rises (5), vital answers are required to improve prevention, diagnosis, treatment, rehabilitation, and delivery of care. In association with the James Lind Alliance, this BASK, BOSTAA and BOA supported prioritising exercise was undertaken over a year. Methods. The James Lind Alliance methodology was followed; a modified nominal group technique was used in the final workshop. An initial survey invited patients and healthcare professionals to submit their uncertainties regarding soft tissue knee injury prevention, diagnosis, treatment, rehabilitation, and delivery of care. Seventy-four questions were formulated to encompass common concerns. These were checked against best available evidence. Following the interim survey, 27 questions were taken forward to the final workshop in January 2023, where they were discussed, ranked, and scored in multiple rounds of prioritisation by groups of healthcare professionals, patients, and carers. Results. Over 1000 questions were submitted initially. Twenty-seven were taken forward to the final workshop following the surveys. Nearly half of the responses were from patients/carers. The Top 10 (Figure 1) includes prevention, diagnosis, treatment, and rehabilitation questions, reflecting the concerns of patients, carers, and a wider multidisciplinary team. Conclusion. This validated process has generated an important, wide- ranging Top 10 priorities for future soft tissue knee injury research. These have been submitted to the National Institute for Health and Care Research and are now available for researchers to investigate. The final 27 questions which were taken to the final workshop have also been published on the James Lind Alliance website. Research into these questions will lead to future high-quality research, thus improving patient care & outcomes. For any figures or tables, please contact authors directly

Multiligament knee injuries (MLKI) are associated with significant morbidity and healthcare requirements. The primary aim of this study is to report the patient reported outcomes measures (PROMs) after reconstructive surgery.

Patients undergoing surgery for MLKI between 2014 and 2018 in the single large-volume trauma centre were included. Electronic patient records were reviewed for demographic data, details of surgery and complications. PROMs collected were EQ-5D-5L, Lysholm Knee Score (LKS), UCLA Activity and Sport and patient satisfaction.

Thirty-five patients were included. Mean age was 31 years (range 16-66), and 71% were male. The most common mechanism of injury was sports-related (71%). Obesity was present in eight (23%) patients. No vascular injuries were recorded and four patients sustained nerve injuries. PROMs were available for 18 patients (51%) with a median follow up of 4.5 years. Median EQ-5D-5L was 0.78 (IQR 0.14). Median LKS was 84.5 (IQR 21) and there was no correlation with time to surgery (p=0.43). Grade of MLKI did not impact LKS (p=0.09). Fifteen patients (83%) saw a reduction in their activity level. All patients were satisfied with their surgical treatment. Recurrent instability was noted in four patients (11%). Three patients (8%) required further surgery (one revision reconstruction, one meniscectomy, one conversion to a hinged knee replacement.

This study demonstrates two groups of patients who sustain MLKI: the sporting population and obese patients. Health related quality of life, functional outcomes and satisfaction are high after surgery. Time to surgery did not impact on functional outcomes.

Introduction

Patellofemoral instability is one of the most common presentations to a children's orthopaedic clinic. Recurrent patellar dislocations and instability episodes are painful, disabling and increase the risk of irreversible chondral damage. The medial patellofemoral ligament is the primary static stabiliser to prevent lateral dislocation of the patella and is almost always torn or attenuated in these cases. Reconstruction of this ligament is commonly performed using autologous hamstring tendon however there has been some interest recently in use of quadriceps tendon as a graft. Children with patellar instability also present unique challenges due to the small size of the patella and the presence of open growth plates which may require adaptations to the common techniques.

The aim of our study was to compare the incidence of post-operative anterior knee discomfort after anterograde tibial nailing by suprapatellar and infrapatellar approaches. 95 subjects presenting with a tibial fracture requiring an intramedullary nail were randomised to treatment using a suprapatellar (SP) or infrapatellar (IP) approach. Anterior knee discomfort was assessed at 4 months, 6 months and 1 year post operatively using the Aberdeen Weightbearing Test-Knee (AWT-K), knee specific patient reported outcome measures and the VAS pain score. The AWT-K is an objective measure which uses weight transmitted through the knee when kneeling as a surrogate for anterior knee discomfort. 53 patients were randomised to an SP approach and 42 to an IP approach. AWT-K results showed a greater mean proportion of weight transmitted through the injured leg compared to the uninjured leg when kneeling in the SP group compared to the IP group at all time points at all follow-up visits. This reached significance at 4 months for all time points except 30 seconds. It also reached significance at 6 months at 0 seconds and 1 year at 60 seconds. We conclude that the SP approach for anterograde tibial nailing reduces anterior knee discomfort post operatively compared to the IP approach

Successful return to work (RTW) is a crucial outcome after primary total knee arthroplasty (TKA) in patients under 65 years old. We aimed to determine whether TKA facilitated RTW in patients <65 years, whose intention was to return preoperatively. We prospectively assessed 106 TKA patients under 65 years over a 1 year period both preoperatively and at 1 year following surgery. Patient demographics were collected including Oxford knee score, Oxford-APQ, VAS pain/health scores and EQ-5D. A novel questionnaire was distributed to delineate pre-operative employment status and post-operative intentions. This included questions on nature of pre and post-operative occupation, whether joint disease affected their ability to work and details of retirement plans and how this was affected by their knee. 69 patients intended to return to work following their TKA. Following arthroplasty, 57/69 patients (82.6%) returned to work at a mean of 16.4 weeks (SD 16.6). Univariate analysis showed significant factors facilitating RTW included, pre-operative oxford knee score, pre-operative Oxford-APQ score and pre-operative EQ-5D score. These were not predictive on multivariate analysis. This study finds that TKA facilitates return to work in 83% of those who intend to return to work following their surgery. This could have significant positive and health and financial cost implications for the individual, health system and society

The aims of this study were to undertake a prospective randomised trial to compare functional outcome, and range of motion after treatment of medial collateral ligament injuries by either early unprotected mobilisation or mobilisation with a hinged brace. Patients were randomised into either unprotected mobilisation or mobilisation with a hinged brace. Assessments occurred at 2 weeks, 6 weeks, 3 months and 6 months. Outcome measures included validated questionnaires (International Knee Documentation Committee and Knee Injury and Osteoarthritis Outcome Score scores), range of motion measurements and strength testing. Eighty six patients (mean age 30.4) were recruited. There were 53 men and 33 women. The mode of injury was sport in 56 patients (65%) with football, rugby and skiing being the most common types of sport involved. The mean time to return to full weight bearing was 3 weeks in both groups. The mean time to return to work was 4.6 weeks in the braced group and 4.1 weeks in the non-braced group (p=0.79). Return to running was at a mean of 14.3 weeks in the braced group and 12.8 weeks in the non-braced group (p=0.64). Return to full sport was 22 weeks in the braced group and 22.1 weeks in the non-braced group (p=0.99). There was no significant difference in range of movement or pain scores between the two groups at 2,6,12 and 24 weeks. The use of a hinged knee brace does not influence recovery after a medial collateral injury

The objective of this study was to compare differences in alignment following robotic arm-assisted bi-unicompartmental knee arthroplasty (Bi-UKA) and conventional total knee arthroplasty (TKA). This was a prospective, randomised controlled trial of 70 patients. 39 TKAs were implanted manually, as per standard protocol at our institution, and 31 Bi-UKA patients simultaneously received fixed-bearing medial and lateral UKAs, implanted using robotic arm-assistance. Preoperative and 3-month postoperative CT scans were analysed to determine hip knee ankle angle (HKAA), medial distal femoral angle (MDFA), and medial proximal tibial angle (MPTA). Analysis was repeated for 10 patients by a second rater to validate measurement reliability by calculating the intra-class correlation coefficient (ICC). Mean change in HKAA towards neutral was 2.7° in TKA patients and 2.3° in Bi-UKA patients (P=0.6). Mean change in MDFA was 2.5° for TKA and 1.0° for Bi-UKA (P<0.01). Mean change in MPTA was 3.7° for TKA and 0.8° for Bi-UKA (P<0.01). Mean postoperative MDFA and MPTA for TKAs were 89.8° and 89.6° respectively, indicating orientation of femoral and tibial components perpendicular to the mechanical axis. Mean postoperative MDFA and MPTA for Bi-UKAs were 91.0° and 86.9° respectively, indicating a more oblique joint line orientation. Inter-rater agreement was excellent (ICC>0.99). Early functional activities, according to the new Knee Society Scoring System, favoured Bi-UKAs (P<0.05). Robotic arm-assisted, cruciate-sparing Bi-UKA better maintains the natural anatomy of the knee in the coronal plane and may therefore preserve normal joint kinematics, compared to a mechanically aligned TKA. This has been achieved without significantly altering overall HKAA

Counter-insurgency warfare in recent military operations has been epitomised by the use of Improvised Explosive Devices (IED) against coalition troops. Emerging patterns of skeletal fractures, limb amputations and organ injuries, which are caused by these weapons have been described over recent years. This paper describes a retrospective case series of knee dislocations caused by IEDs in recent conflict. Data was obtained about military personnel from 2006 to 2011, who had sustained a knee dislocation while serving in Afghanistan from a prospectively gathered database, the Joint Theatre Trauma Registry (JTTR), maintained by the Academic Department of Military Emergency Medicine, Royal Centre for Defence Medicine. The diagnosis of knee dislocation and its associated skeletal injuries was assessed by review of all relevant plain radiographs, computed tomography scans and magnetic resonance images. The mechanism of injury, incidence of vascular injuries and other skeletal injuries was recorded. During the study period, 23 casualties sustained a knee dislocation caused by an IED. Four casualties had an associated popliteal vascular injury. Eleven injuries were caused in enclosed spaces, and 10 injuries caused by IEDs out in the open. Anterior dislocations were common in the group caused in enclosed spaces. 19/20 patients had at least one other skeletal fracture. Knee dislocations represent an uncommon but important diagnosis in modern warfare. Urgent and careful assessment for any associated vascular injuries or other skeletal injuries may help ensure timely treatment and promote future recovery. Mitigation against knee dislocation may be possible in the enclosed environment because of the predictable pattern of injury

The superficial anterior vasculature of the knee is variably described; most of our information comes from anatomical literature. Descriptions commonly emphasise medial-dominant genicular branches of the popliteal artery. Describing the relative contribution of medial and lateral vessels to the anastomotic network of the anterior knee may help provide grounds for selecting one of a number of popular incisions for arthrotomy. The aim of this study is to describe the relative contribution of vessels to anastomoses supplying the anterior knee. Cadaveric knees (n = 16) were used in two cohorts. The first cohort (n = 8) were injected at the popliteal artery with a single colour of latex, and then processed through a modified diaphanisation technique (chemical tissue clearance) before final dissection and analysis. This was repeated for the second cohort, but with initial dissection to identify potential source vessels at their origin. Each source vessel was injected with a different colour of latex. The dominant sources were determined in each specimen. The majority of the specimens (n = 13; 81%) demonstrated that an intramuscular branch though the vastus medialis muscle was the dominant vessel. Anastomoses were most common over the medial side of the knee, both superiorly and inferiorly (3-5 anastomoses in all cases). Anastomosis over the lateral knee was infrequent (1 anastomosis in 1 specimen). The results suggest that anterior vasculature of the knee is predominately medial in origin, but not from the genicular branches as previously described. This network of vessels found in the anterior knee is thought to be the main supply to the patella, extensor apparatus, anterior joint capsule and skin. Optimum placement of incision for arthrotomy is a subject of debate. Considering the main blood supply to the anterior knee may help in choosing a particular approach

Aim. The purpose of this study was to investigate the effects of plaster/splint immobilisation of the knee/ankle on driving performance in healthy individuals. Methods & Materials. Twenty-three healthy drivers performed a series of emergency brake tests in a driving simulator having applied above knee plaster casts, below knee plaster casts, or a knee brace with increasing restriction. Results. Our study showed that compared to braking normally, total brake reaction time was significantly longer when wearing an above knee plaster cast, below knee plaster cast or a knee brace with zero degrees of freedom (p<0.001). Increases in movement time from accelerator to brake accounted for some of the increase in the total brake reaction time. However, unexpectedly thinking time also increased with the level of restriction (p<0.001). Conclusion. These results suggest that all patients wearing a plaster cast or knee brace are significantly impaired in their ability to perform an emergency stop. We suggest changes to the legislation that prevents patients driving with lower limb plaster casts or knee braces

Background. In poliomyelitis; hand to knee gait is the sum of quadriceps weakness and fixed knee flexion deformity. Limb shortening is another added problem. Usually, each problem is attacked separately; with variable end results and complication rates for each procedure. Patients and methods. 22 patients (16–46 y.); with poliomyelitis with hand to knee gait due to fixed knee flexion deformity of mild to moderate degree (10–400); and limb shortening of 4.5–9.5 cm., were managed simultaneously by a single operation. A distal femoral metaphyseal anterior closing wedge (recurvatum) corrective osteotomy was done to treat acutely the fixed knee flexion deformity(and subsequently hand to knee gait). A modified Wagner or Orthofix frame was applied as a mono-plane mono-axial lengthening device to stabilize the osteotomy and to lengthen the short limb. Lengthening was started in all cases two weeks post-operatively. Results. All cases showed full correction of the deformity with elimination of the hand to knee gait problem and all showed - the desired - limb length equalization. The femora were lengthened to an average of 6.4 cm.(= 21% of original femoral bone length), range of lengthening was: 4–9 cm. (= 11–26%). The average healing index was 37 days per centimeter (with a range of 31 to 53 days per centimeter.). Conclusion. Simultaneous management of hand to knee and limb shortening could be achieved by a single osteotomy which is used to extend the knee acutely and for distraction two weeks later using a mono-lateral frame. Results were good, complications were few and accepted and the procedure is well tolerated by the patients

Aims

The aim of this study was to assess the feasibility of conducting a full-scale, appropriately powered, randomized controlled trial (RCT) comparing internal fracture fixation and distal femoral replacement (DFR) for distal femoral fractures in older patients.

Conventional computer navigation systems using bone fixation have been validated in measuring anteroposterior (AP) translation of the tibia. Recent developments in non-invasive skin-mounted systems may allow quantification of AP laxity in the out-patient setting. We tested cadaveric lower limbs (n=12) with a commercial image free navigation system using passive trackers secured by bone screws. We then tested a non-invasive fabric-strap system. The lower limb was secured at 10° intervals from 0° to 60° knee flexion and 100N of force applied perpendicular to the tibial tuberosity using a secured dynamometer. Repeatability coefficient was calculated both to reflect precision within each system, and demonstrate agreement between the two systems at each flexion interval. An acceptable repeatability coefficient of ≤3mm was set based on diagnostic criteria for ACL insufficiency when using other mechanical devices to measure AP tibial translation. Precision within the individual invasive and non-invasive systems measuring AP translation of the tibia was acceptable throughout the range of flexion tested (repeatability coefficient ≤1.6 mm). Agreement between the two systems was acceptable when measuring AP laxity between full extension and 40° knee flexion (repeatability coefficient ≤2.1 mm). Beyond 40° of flexion, agreement between the systems was unacceptable (repeatability coefficient >3 mm). These results indicate that from full knee extension to 40° flexion, non-invasive navigation-based quantification of AP tibial translation is as accurate as the standard invasive system, particularly in the clinically and functionally important range of 20° to 30° knee flexion. This could be useful in diagnosis and post-operative follow-up of ACL pathology

Background. Jumper's knee is the result of violent and repeated contractions of quadriceps muscle caused by rapid acceleration and deceleration, jumping and kicking that load on patellar tendon stressing its mechanical resistance. The porpose of this retrospective study is to analyze the results, after the debridment of the patellar tendon and the patellar apex abrasion performed by arthroscopy, at a mean follow-up of seven years. Methods. From 1996 to 2006, sixty-four patients (seventy-three knees) affected by jumper's knee underwent surgical tretment after failure of nonoperative treatment. All knees were operated on by the same surgeon using the same surgical technique: arthroscopic debridement of the articular face of patellar tendon and arthroscopic abrasion of patellar apex. Pre-operative and post-operative evaluation was made according to IKDC score, Lysholm Knee Scale and VISA-P score. Results. The pre-operative subjective IKDC score was 52,96. This score significantly increased to 94,72 at 12 months post-operation, and has remained nearly constant at 10 years of follow-up. The mean pre-operative Lysholm Knee Scale was 51,57 and significantly increased to 86,48 at 12 months post-operation again remaining nearly constant at 10 years of follow-up. The score according to VISA-P which was pre-operatively 35,32 increased to 69,80 at 12 months post-operation and was 69,35 at 10 years of follow-up. Nineteen of the twenty-seven patients who were involved in competitive sport continued it at the same level and twenty-four were symptoms-free. Conclusions. For these satisfactory results, for the low aggressivity of this surgery, for the short recovery time and the faster return to sport we think that the debridment of the patellar tendon and the patellar apex abrasion performed by arthroscopy is the technique to prefer for surgical treatment of Jumper's Knee

It is widely accepted by orthopaedic surgeons that antibiotics should be withheld until aspiration has been performed to increase the odds of identifying an organism in septic arthritis. Patients often present to other specialties that may not be as familiar with these principles. Twenty-five of forty-nine patients with septic arthritis of the native or prosthetic knee had received antibiotics prior to review by the orthopaedic service. Patients were significantly less likely to demonstrate an organism on initial microscopy (entire cohort p=0.001, native knees p=0.006, prosthetic knees p=0.033) or on subsequent culture (entire cohort p=0.001, native knees p=0.017, prosthetic knees p=0.012) of their aspirate if they had received antibiotics. The sensitivity of microscopy dropped from 0.58 to 0.12 when patients had received antibiotics (native knees 0.46 to 0, prosthetic knees 0.72 to 0.27). The sensitivity of the culture dropped from 0.79 to 0.28 when the patient had received antibiotics (native knees 0.69 to 0.21, prosthetic knees 0.91 to 0.36). Patients treated with empirical antibiotics are less likely to demonstrate an organism on microscopy and culture of their initial aspirate. There is a significantly high false negative rate associated with knee aspiration, particularly with prior administration of antibiotics

The aim of this study was to report the incidence of arthrofibrosis of the knee and identify risk factors for its development following a fracture of the tibial plateau. We carried out a retrospective review of 186 patients (114 male, 72 female) with a fracture of the tibial plateau who underwent open reduction and internal fixation. Their mean age was 46.4 years (19 to 83) and the mean follow-up was16.0 months (6 to 80). A total of 27 patients (14.5%) developed arthrofibrosis requiring a further intervention. Using multivariate regression analysis, the use of a provisional external fixator (odds ratio (OR) 4.63, 95% confidence interval (CI) 1.26 to 17.7, p = 0.021) was significantly associated with the development of arthrofibrosis. Similarly, the use of a continuous passive movement (CPM) machine was associated with significantly less development of arthrofibrosis (OR = 0.32, 95% CI 0.11 to 0.83, p = 0.024). The effect of time in an external fixator was found to be significant, with each extra day of external fixation increasing the odds of requiring manipulation under anaesthesia (MUA) or quadricepsplasty by 10% (OR = 1.10, p = 0.030). High-energy fracture, surgical approach, infection and use of tobacco were not associated with the development of arthrofibrosis. Patients with a successful MUA had significantly less time to MUA (mean 2.9 months; . sd. 1.25) than those with an unsuccessful MUA (mean 4.86 months;. sd. 2.61, p = 0.014). For those with limited movement, therefore, performing an MUA within three months of the injury may result in a better range of movement. . Based our results, CPM following operative fixation for a fracture of the tibial plateau may reduce the risk of the development of arthrofibrosis, particularly in patients who also undergo prolonged provisional external fixation. Cite this article: Bone Joint J 2015;97-B:109–14