Aims. We aimed to assess the reliability and validity of OpenPose, a posture estimation algorithm, for measurement of knee range of motion after total knee arthroplasty (TKA), in comparison to radiography and goniometry. Methods. In this prospective observational study, we analyzed 35 primary TKAs (24 patients) for knee osteoarthritis. We measured the knee angles in flexion and extension using OpenPose, radiography, and goniometry. We assessed the test-retest reliability of each method using intraclass correlation coefficient (1,1). We evaluated the ability to estimate other measurement values from the OpenPose value using linear regression analysis. We used intraclass correlation coefficients (2,1) and Bland–Altman analyses to evaluate the agreement and error between radiography and the other measurements. Results. OpenPose had excellent test-retest reliability (intraclass correlation coefficient (1,1) = 1.000). The R. 2. of all regression models indicated large correlations (0.747 to 0.927). In the flexion position, the intraclass correlation coefficients (2,1) of OpenPose indicated excellent agreement (0.953) with radiography. In the extension position, the intraclass correlation coefficients (2,1) indicated good agreement of OpenPose and radiography (0.815) and moderate agreement of goniometry with radiography (0.593). OpenPose had no systematic error in the flexion position, and a 2.3° fixed error in the extension position, compared to radiography. Conclusion. OpenPose is a reliable and valid tool for measuring flexion and extension positions after TKA. It has better accuracy than goniometry, especially in the extension position. Accurate measurement values can be obtained with low error, high reproducibility, and no contact, independent of the examiner’s skills. Cite this article: Bone Joint Res 2023;12(5):313–320

The aim of this study was to investigate the pre-operative factors predicting the knee range of motion during stair ascending and descending a year after total knee arthroplasty. The pre-operative and one year post-operative results of fifty six patients with osteoarthritis were analysed. Range of knee motion during stair ascent and descent was recorded using electrogoniometry. Pre-operative measures were grouped in three different domains; the Demographic Domain with age and Body Mass Index (BMI), the Body Function Domain with knee range of motion in long sitting (ROMsit), Knee extensor moment, Pain on a Visual Analogue Scale and the stiffness component of the Western Ontario McMaster University Osteoarthritis Index (WOMAC) and thirdly the Psychosocial Domain with the Tampa scale for ‘fear of movement’ (TSK) and the sense of helplessness due to pain. Hierarchical Multiple Regression was used to analyse the relative importance of measures grouped into the three domain blocks on range of motion of the operated knee during stair ascent and descent. Model 1 contained domain block 1, model 2 included domain blocks 1 and 2 and model 3 included domain blocks 1,2 and 3. Learned helplessness was a significant predicting factor for stair descent (beta; −0.538, p=0.025) while for stair ascent, age (beta 0.375, p=0.005) and ROMsit (beta 0.365, p=0.021) were significant predicting variables. These results show that postoperative stair ascent and descent are predicted by different pre-operative factors. For stair ascent the demographic factors age and function factor ROM are important, while for stair descent, only the addition of the psychosocial factors in model 3 resulted in a significant change. These results indicate that treatment of patients with end-stage osteoarthritis should not only be aimed at improving range of motion of the knee but should also take into account psychosocial variables such as a sense of helplessness due to pain

Introduction: ROM after TKA can be influenced by multi-factors such as preoperative range of motion, body habitus, implant design, intraoperative surgical technique, and postoperative rehabilitation. Recently many implant manufacturers have made modifications to traditional total knee designs to improved maximal knee flexion and range of motion. Some posterior cruciate ligament (PCL) stabilized total knee prostheses that incorporate design features intended to improve knee kinematics in high flexion were introduced and the use of these prostheses has attracted attention. Recently in the cruciate retaining (CR) prosthesis, high-flexion knee (CR-Flex) and gender-specified prosthesis were designed to allow a greater and safer flexion after TKA. The aim of this study was to evaluate the effect of cruciate retaining typed different femoral component design on knee range of motion using a computerized navigation system. Materials & method: 30 patients who underwent primary TKA because of primary osteoarthritis were included. EM navigation system was used in all cases. After tibia and femoral cutting using standard CR cutting block, standard fixed bearing CR knee (NexGen CR, Zimmer, Warsaw, IN) trial was inserted. If surgeon is satisfactory with alignment, stability and ligament balancing, the maximal knee extension and flexion was recorded using gravity by navigation system. Then, high-flexion fixed bearing CR knees(NexGen CR-Flex and Gender solution NexGen CR-Flex knee, Zimmer, Warsaw, IN) trial was inserted after additional posterior cutting. The maximal knee extension and flexion was evaluated exactly same way. Results: Preoperative mean varus deformity was 10.52°. The mean flexion contracture was 7.52±6.81° and further flexion 129.9±7.94°. The average intraoperative maximal flexion of NexGen CR was 133.5±5.35° (125–146°) and that of hyper-flexion design were 135.5±5.77°(125–147°) in Nexgen CR-Flex and 136.1±5.76°(126–146°) in Gender knee. All knees showed greater than 125° of flexion regardless of the implant design. All knees can achieve physiologic leg alignment and nearly full extension of the knee after operation. Conclusion: Hyper flexion designs showed subtle increase in mean maximal flexion and overall range of motion of the knee compared with the standard design, when it measured using navigation system intraoperatively. But clinically, it is not certain that these differences can lead to significant improvement of range of motion

Abstract

INTRODUCTION: Range of motion following TKA is a commonly assessed and important outcome parameter. The reported knee ROM is often measured using manual goniometers. The accuracy of goniometer in measuring ROM of the knee is not known. We compared the knee ROM measured with a manual goniometer and compared that to measurements obtained from computer assisted navigation system.

METHODS: This prospective ongoing study has so far recruited 60 patients (71 knees) undergoing TKA by a single surgeon. Measurements of the ROM were performed intraoperatively using a 14 inch 360° Nexgen Baseline® goniometer, validated by physical therapists, and the Stryker knee navigation system^™. Consistent anatomical landmarks were used to obtain flexion and extension measurements. Each goniometer and navigation measurement was performed twice by the same reader.

RESULTS: Goniometer was more inaccurate in measuring the knee ROM than the navigation. There was a 5.07° difference between two measurements obtained with the goniometer compared to a mean discrepancy of 1.15° using the navigation system. Further, the ROM measured by navigation was on average 13.9° larger than that measured by the goniometer. BMI affected the ROM recording obtained by both the goniometer and the navigation system.

DISCUSSION AND CONCLUSION: This study indicates that goniometer is not an accurate tool for measurements of knee ROM as there is a marked discrepancy between two goniometer readings. The navigation system seemed to produce more consistent, but markedly higher, readings than a manual goniometer. Reported results on knee ROM in the literature need to be interpreted with caution and scrutinized for potential inaccuracy of the measuring tool.

Background:

For the past four decades controversy surrounds the decision to retain or sacrifice the posterior cruciate ligament during a total knee arthroplasty. To our knowledge no study has been done to describe the effect of releasing the PCL on the range of motion of the knee.

Introduction: Range of motion (ROM) is an important measure of the success of knee Arthroplasty. The extent to which pain relief contributes to improvements in knee ROM in total knee Arthroplasty (TKA) patients is unknown. This prospective study assessed the separate effects of pain abolition and surgery on ROM in a group of 141-osteoathritic patient’s undergoing TKA. Pain had a significant inhibitory effect on knee ROM. Improvements in ROM following TKA may be primarily due to pain relief.

Methods: 141 randomly selected patients underwent LCS total knee arthroplasty (De Puy). A single surgeon performed all operations, using an identical surgical technique. Passive flexion and extension were measured when awake, under anaesthesia, and post-operatively under anaesthesia.

Paired t-tests were used to test for significant differences between the measurements. Independent samples t-tests were used to test for significant differences between the changes in flexion, extension and ROM between the time points tested.

Results:

When awake the mean flexion was 116.8°, extension 3.8°, and ROM 113.0°

Knee flexion (p < 0.0001) and range of motion (p < 0.0001) were significantly greater and knee extension (p < 0.0001) was significantly reduced following anaesthesia only. A further significant increase in knee flexion (p < 0.0001) and range of motion (p = 0.00014) was observed post –operatively under anaesthetic. However knee extension did not significantly increase further (p = 0.29). The average improvement in range of motion once anaesthetised was 16.4° (SD = 13.1°) with the majority of this improvement due to an increase of flexion (average increase of 13.4° (SD = 11.9°) rather than an increase in extension (average increase of 3.0° (SD = 4.2°).

The combined effect of surgery and anaesthetic was 20.5° (SD = 12.3°), with the majority of this improvement due to an increase of flexion (average increase of 17° (SD = 8.5°) rather than an increase in extension (average increase of 3.6° (SD = 6.0°).

Discussion: Pain abolition resulted in a mean increase of 16.4° in the range of motion, and both TKA combined with pain abolition further increased significantly the range of motion to a mean of 20.5°. This study suggests that improvements in ROM following total knee arthroplasty are primarily due to reduction in the symptoms of pain and that other factors such as surgical technique and prosthesis design can further increase ROM.

Future studies should record the measurements of passive flexion, extension and range of motion in the anaesthetised patient, as this will allow objective assessment of changes in range of movement.

We sought to validate a method of measuring the range of motion of knees on radiographs as part of a new system of “Virtual Knee Clinics”. The range of motion of 52 knees in 45 patients were first obtained clinically with goniometers and compared to radiographs of these patients' knees in full active flexion and extension. Four methods of plotting the range of motion on the radiographs were compared. The intra-class correlation coefficient (ICC) for inter-rater reliability using the goniometer was very high; ICC=0.90 in extension and 0.85 in flexion. The best ICC for radiographic measurement in extension was 0.86 indicating substantial agreement and best ICC in flexion was 0.95 (method 4). ICC for intra-rater reliability was 0.98 for extension and 0.99 for flexion on radiographic measurements. Measuring range of motion of the knee has never previously been validated in the literature. This study has allowed us to set up a “Virtual Knee Clinic,” combining postal questionnaires and radiographic measurements as a surrogate for knee function. We aim to maintain high quality patient surveillance following knee arthroplasty, reduce our new to follow-up ratios in line with Department of Health guidelines and improve patient satisfaction through reduced travel to hospital outpatients

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

Aims. To explore the clinical efficacy of using two different types of articulating spacers in two-stage revision for chronic knee periprosthetic joint infection (kPJI). Methods. A retrospective cohort study of 50 chronic kPJI patients treated with two types of articulating spacers between January 2014 and March 2022 was conducted. The clinical outcomes and functional status of the different articulating spacers were compared. Overall, 17 patients were treated with prosthetic spacers (prosthetic group (PG)), and 33 patients were treated with cement spacers (cement group (CG)). The CG had a longer mean follow-up period (46.67 months (SD 26.61)) than the PG (24.82 months (SD 16.46); p = 0.001). Results. Infection was eradicated in 45 patients overall (90%). The PG had a better knee range of motion (ROM) and Knee Society Score (KSS) after the first-stage revision (p = 0.004; p = 0.002), while both groups had similar ROMs and KSSs at the last follow-up (p = 0.136; p = 0.895). The KSS in the CG was significantly better at the last follow-up (p = 0.013), while a larger percentage (10 in 17, 58.82%) of patients in the PG chose to retain the spacer (p = 0.008). Conclusion. Prosthetic spacers and cement spacers are both effective at treating chronic kPJI because they encourage infection control, and the former improved knee function status between stages. For some patients, prosthetic spacers may not require reimplantation. Cite this article: Bone Joint Res 2024;13(6):306–314

Abstract. Introduction. This study compared biomechanical and functional parameters of a total knee arthroplasty (TKA) implant (Cemented Zimmer Hi-Flex) against healthy older adults to determine whether knee biomechanics was restored in this patient population. Methodology. Patients with a primary TKA and healthy adults >55 years old with no musculoskeletal deficits or arthritis participated. Bilateral knee range of motion (RoM) was assessed with a goniometer, then gait patterns were analysed with a 3D motion-capture system. An arthrometer then quantified anterior-posterior laxity of each knee. Statistical analyses were performed in SPSS (α=0.05; required sample size: n=21 per group). Results. 25 knees were replaced in 21 patients. Nine presented with fixed flexion deformities (FFD) (13.3±5.6°). FFDs were abolished intraoperatively, and the average flexion increased from 124.8±9.1° to 130.9±5.8°. At 9.6±3.2 years postoperatively, the patients achieved poorer RoM than healthy controls (n=23); p<0.0001. These differences were due to limited flexion in the knee. Patients also failed to achieve the same degree of flexion as controls bilaterally during gait. No differences were observed during mid-flexion; a state that has been associated with instability (p=0.614). There were no differences between groups in knee laxity. Conclusion. Patients in this study had similar gait patterns to healthy older adults during mid-flexion, and were no more likely to exhibit anterior-posterior translation of the knee >7mm; a known risk factor of instability. However, the flexion range was poorer. This led to bilateral pathological knee flexion patterns during gait. Further research should identify the cause of these limitations

Abstract. INTRODUCTION. The anatomic distal femoral locking plate (DF-LCP) has simplified the management of supracondylar femoral fractures with stable knee prostheses. Osteoporosis and comminution seem manageable, but at times, the construct does not permit early mobilization. Considerable soft tissue stripping during open reduction and internal fixation (ORIF) may delay union. Biological plating offsets this disadvantage, minimizing morbidity. Materials. Thirty comminuted periprosthetic supracondylar fractures were operated from October 2010 to August 2016. Fifteen (group A) were treated with ORIF, and fifteen (group B) with closed (biological) plating using the anatomical DF-LCP. Post-operatively, standard rehabilitation protocol was followed in all, with hinged-knee-brace supported physiotherapy. Clinico-radiological follow-up was done at 3 months, 6 months, and then yearly (average duration, 30 months), and time to union, complications, failure rates and function were evaluated. Results. Average time to union was 4.5 months (range, 3–6 months) in group A, and 3.5 months (range, 2.5–5 months) in group B. Primary bone grafting was done in twelve patients (all group A). At final follow-up, all fractures had healed, and all (but two) patients were walking unsupported, with no pain or deformity, with average knee range of motion (ROM) of 90° (range, 55 to 100°). Two patients had superficial infection (group A), two had knee stiffness (group A), one had shortening of 1.5cm (group B) and one had valgus malalignment of 10 degrees (group B). Conclusion. Biological plating in comminuted supracondylar fractures about stable TKA prostheses is an excellent option, may obviate need for bone grafting, and reducing complications

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

Abstract. 20% of patients are severely dis-satisfied following total knee arthroplasty (TKA). Arthrofibrosis is a devastating complication preventing normal knee range of motion (ROM), severely impacting patient's daily living activities. A previous RCT demonstrated superiority of a high intensity stretching programme using a novel device the STAK tool compared with standard physiotherapy in TKA patients with arthrofibrosis. This study analyses the results when the previous “standard physiotherapy” group were subsequently treated with the STAK tool. Methods. 15 patients post TKA with severe arthrofibrosis and mean ROM 71° were recruited, (three cases had previously failed manipulation under anaesthetic (MUA). Patients received 8 weeks standard physiotherapy, then treatment with the STAK at home for 8 weeks. ROM, extension, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Oxford Knee Scores (OKS) were collected at various time-points. Results. Following standard physiotherapy there were small improvements in ROM (8°) (p<0.01), but no significant improvements in extension, OKS or WOMAC (p=0.39). Following the STAK treatment all outcomes significantly improved (p<0.01). STAK group; mean ROM (21° versus 8°, p < 0.001), extension 9° versus 2° (p < 0.01), WOMAC (18 points versus 3, p < 0.01), and OKS (8 points versus 4, p<0.01). No patients suffered any complications relating to the STAK. Conclusions. The STAK is effective in increasing ROM, extension and function, whilst reducing pain and stiffness. The device can be considered a cost-effective and valuable treatment following TKA. This is likely to increase the overall satisfaction rate and has potential to reduce the need for MUA

To assess long and short term kinematic gait outcomes after rectus femoris transfers (RFT) in ambulatory children with cerebral palsy (CP). A retrospective review was conducted of ambulatory children with spastic diplegic CP, who had RFT plus motion analysis preoperatively and 1 year post-operatively. Those with 5 and 10 year post-operative motion analysis were also included. The primary variables were: peak knee flexion range of motion in swing (PKFSW), timing of peak knee flexion in swing as a percent of the gait cycle (PKF%GC), and knee range of motion from peak to terminal swing (KROM). Responders and non-responders were identified. Descriptive, kinematic and kinetic variables were evaluated as predictors of response. 119 ambulatory children (237 limbs) with spastic diplegic CP who had RFT were included. Mean age at surgery was 10.2 years (range 5.5 to 17.5). Sixty-seven participants were classified at GMFCS Level II and 52 at GMFCS Level III. All participants (237 limbs) had a preoperative and 1 year postoperative motion analysis. Motion analysis at 5 and 10 years post-operatively included 82 limbs and 28 limbs, respectively. Ninety-three (39%) limbs improved in both PKFSW and PKF%GC. PKFSW improved in 59% of limbs. Responders started 1.2 SD below the mean PKFSW preoperatively, and improved by an average of 1.9 SD to reach a normal range at 1 year post-operatively (p < 0.05). Improvement was maintained at 5 and 10 years postoperatively. Those at GMFCS level II were more likely [OR 1.71, CI 1.02, 2.89] to have improved PKFSW at 1 year postoperatively than those at GMFCS level III. PKF%GC improved in 70% of limbs. Responders had delayed PKF%GC, starting 10 SD above the mean (later in the gait cycle) preoperatively. Their timing improved towards normal values: 5 SD, 5.9 SD, 3.5 SD from the mean, (earlier in the gait cycle) at 1, 5 and 10 years postoperatively, respectively (p<0.05). KROM improved in only 24% of limbs. For all variables, there was a significant difference in mean preoperative values between responders and non-responders (p<0.05). RFT improves short and long-term kinematic gait outcomes. The majority of children responded to RFT with improvements in PKFSW or PKF%GC at 1, 5, and 10 years post RFT. GMFCS level is a predictor of improved PKFSW, with children at GMFCS Level II having an increased likelihood of improvement at 1 year post surgery. Children who have worse preoperative values of PKFSW, PKF%GC, and KROM have a greater potential for benefit from RFT. Characteristics associated with responders who maintain long term positive outcomes need to be identified

Variations in the pivot shift test have been proposed by many authors, though, a test comprised of rotatory and valgus tibial forces with accompanied knee range of motion is frequently utilised. Differences in applied forces between practitioners and patient guarding have been observed as potentially decreasing the reproducibility and reliability of the pivot shift test. We hypothesise that a low-profile pivot shift test (LPPST) consisting of practitioner induced internal rotatory and anterior directed tibial forces with accompanied knee range of motion can elicit significant differences in internal tibial rotation and anterior tibial translation between the anterior cruciate ligament (ACL) deficient and ACL sufficient knee. Fresh, frozen cadaver knees were used for this study. Four practitioners performed the LPPST on each ACL sufficient knee. The ACL of each knee was subsequently resected and each practitioner performed the LPPST on each ACL deficient knee. Our quantitative assessment utilised computer assisted navigation to sample (10Hz) the anterior translation and internal rotation of the tibia as the LPPST force vectors were applied. We subsequently pooled and averaged data from all four practitioners and analysed the entrance pivot (tibial reduction with knee range of motion from extension into flexion) and the exit pivot (tibial subluxation with knee range of motion from flexion into extension). We observed a significant difference in anterior tibial translation and internal tibial rotation in the ACL deficient vs. ACL sufficient knees during both the entrance and exit pivot phases of the LPPST. The entrance pivot (n=140) was found to have an average maximum anterior tibial translation of 7.83 mm in the ACL deficient knee specimens compared to 1.23 mm in the ACL sufficient knee specimens (p<0.01). We found the ACL deficient knees to exhibit an average maximum internal tibial rotation of 12.38 degrees compared to 11.24 degrees in the ACL sufficient specimens during the entrance pivot (p=0.04). The exit pivot (n=120) was found to have an average maximum anterior tibial translation of 7.82 mm in the ACL deficient knee specimens compared to 1.44 mm in the ACL sufficient knee specimens (p<0.01). The ACL deficient knees exhibited an average maximum internal tibial rotation of 12.44 degrees compared to 11.13 degrees in the ACL sufficient knee specimens during the exit pivot (p=0.02). Our results introduce a physical exam maneuver (LPPST) consisting of practitioner induced internal rotatory and anterior directed forces, with notable absence of valgus force, on the tibia while applying knee range of motion. Our results demonstrate that the LPPST can elicit significant anterior translation and internal rotary differences in an effort to differentiate between the ACL deficient and ACL sufficient knee. Our work will next seek to explore the clinical reproducibility of this physical exam maneuver

Despite multiple published reviews, the optimum method of correction and stabilisation of Blount's disease remains controversial. The purpose of this study is to evaluate the clinical and radiological outcomes of acute correction of late-onset tibial vara by percutaneous proximal tibial osteotomy with circular external fixation using two simple rings. This technique was developed to minimise cost in a context of limited resources. This study was conducted between 2016 and 2020. We retrospectively reviewed the clinical notes and radiographs of 30 patients (32tibiae) who had correction of late-onset tibia by proximal tibial osteotomy and Ilizarov external fixator. All cases were followed up to 2 years. The mean proximal tibial angle was 65.7° (±7.8) preoperatively and 89.8° (±1.7) postoperatively. The mean mechanical axis deviation improved from 56.2 (±8.3) preoperatively to 2.8 (±1.6) mm postoperatively. The mean femoral-tibial shaft angle was changed from – 34.3° (±6.7) preoperatively to 5.7° (±2.8) after correction. Complications included overcorrection (9%) and pin tract infection (25%). At final follow up, all patients had full knee range of motion and normal function. All cases progressed to union and there were no cases of recurrence of deformity. This simple procedure provides secure fixation allowing early weight bearing and early return to function. It can be used in the context of health care systems with limited resources. It has a relatively low complication rate. Our results suggest that acute correction and simple circular frame fixation is an excellent treatment choice for cases of late-onset tibia vara, especially in severe deformities

Introduction. Increasingly young and active patients are concerned about revision arthroplasty forcing the manufacturers to think about revision prostheses that fit to this population while meeting the indications and fitting with bone losses and ligament deficiencies. One of those industrials claims that its system allows the surgeon to rise the constraint from a posterior stabilized (PS) prostheses to a semi-constraint total stabilized (TS) prostheses without modifying the gait pattern thanks to a similar single radius design. The aim of the study was to compare gait parameters in patients receiving either PS or TS knee prostheses. Methods. Nineteen patients in each groups were prospectively collected for this study and compared between each other. All subjects were assessed with a 3D knee kinematics analysis, performed with an optoelectronic knee assessment device (KneeKG®). Were measured for each knees range of motion (ROM) in flexion–extension, abduction–adduction, internal–external rotation and anterior–posterior displacement. Results. There were no significant kinematic differences between PS and TS groups. The ROM in flexion-extension was 44° in PS group vs 46° in TS group, the ROM in internal-external rotation was 5.5° in PS group vs 4°in TS group. Peak varus angle during loading was equal (2.5°) and higher in PS group during swing phases (5.5° vs 3.7°) without any significancy. There appeared to be less antero-posterior translation in the TS group (maximum posterior displacement of −1 mm vs −5 mm) linked to the larger central post-cam without any significancy. Conclusion. TS designed have comparable gait parameters than PS prostheses. Its use won't prejudice the patient concerning the walking pattern

MPFL reconstruction has demonstrated a very high success rate with improved patella stability, physical function, and patient-reported outcomes. However technical error and a lack of consideration of anatomic risk factors have been shown to contribute to failure after MPFL reconstruction. Previous research has also reported a complication rate of 26% following surgery. The purposes of this study were to determine the re-dislocation rate, type and number of complications, and most common additional surgical procedures following MPFL reconstruction. Patients with symptomatic recurrent patellofemoral instability underwent an MPFL reconstruction (n = 268) and were assessed with a mean follow-up of 31.5 months (minimally 24-months). Concomitant procedures were performed in addition to the MPFL reconstruction in order to address significant anatomic or biomechanical characteristics. Failure of the patellofemoral stabilization procedure was defined as post-operative re-dislocation of the patella. Rates of complications and re-procedures were assessed for all patients. The re-dislocation rate following MPFL reconstruction was 5.6% (15/268). There were no patella fractures. A total of 49/268 patients (18.3%) returned to the operating room for additional procedures following surgery. The most common reason for additonal surgery was removal of symptomatic tibial tubercle osteotomy hardware in 24/268 patients (8.9%). A further 9.3% of patients underwent addtional surgery including revision MPFL reconstruction: with trochleoplasty 8/268 (3.0%), with tibial tubercule osteotomy 4/286 (1.5%) and with femoral derotation osteotomy 3/268 (1.1%); manipulation under anaesthesia for reduced knee range of motion 4/268 (1.5%); knee arthroscopy for pain 8/268 (3.0%); and cartilage restoration procedures 3/268 (1.1%). There was 1 case of wound debridement for surgical incision infection. MPFL reconstruction using an a la carte approach to surgical selection demonstrated a post-operative redislocation rate of 5.6%. The rate of complications following surgical stabilization was low, with the most common reason for additional surgery being removal of hardware

Aims. This study aimed to investigate the relationship between changes in patellar height and clinical outcomes at a mean follow-up of 7.7 years (5 to 10) after fixed-bearing posterior-stabilized total knee arthroplasty (PS-TKA). Methods. We retrospectively evaluated knee radiographs of 165 knees, which underwent fixed-bearing PS-TKA with patella resurfacing. The incidence of patella baja and changes in patellar height over a minimum of five years of follow-up were determined using Insall-Salvati ratio (ISR) measurement. We examined whether patella baja (ISR < 0.8) at final follow-up affected clinical outcomes, knee joint range of motion (ROM), and Knee Society Score (KSS). We also assessed inter- and intrarater reliability of ISR measurements and focused on the relationship between patellar height reduction beyond measurement error and clinical outcomes. Results. The ISR gradually decreased over five years after TKA, and finally 33 patients (20.0%) had patella baja. Patella baja at the final follow-up was not related to passive knee ROM or KSS. Interestingly, when we divided into two groups - patella baja and patella normal-alta (ISR ≥ 0.8) - the patella baja group already had a lower patellar height before surgery, compared with the patella normal-alta group. The ISR measurement error in this study was 0.17. Both passive knee flexion and KSS were significantly decreased in the group with a decrease in ISR of ≥ 0.17 at final follow-up. Conclusion. Patellar height gradually decreased over five years of follow-up after TKA. The reduction in patellar height beyond measurement error following TKA was associated with lower clinical outcomes. Cite this article: Bone Jt Open 2021;2(12):1075–1081