A prospective randomized controlled trial comparing CT-based planning with conventional total hip arthroplasty versus robotic arm-assisted total hip arthroplasty.

Aims: Achieving accurate implant positioning and restoring native hip biomechanics are key surgeon-controlled technical objectives in total hip arthroplasty (THA). The primary objective of this study was to compare the reproducibility of the planned preoperative centre of hip rotation (COR) in patients undergoing robotic arm-assisted THA versus conventional THA. Methods: This prospective randomized controlled trial (RCT) included 60 patients with symptomatic hip osteoarthritis undergoing conventional THA (CO THA) versus robotic arm-assisted THA (RO THA). Patients in both arms underwent pre- and postoperative CT scans, and a patient-specific plan was created using the robotic software. The COR, combined offset, acetabular orientation, and leg length discrepancy were measured on the pre- and postoperative CT scanogram at six weeks following surgery. Results: There were no significant differences for any of the baseline characteristics including spinopelvic mobility. The absolute error for achieving the planned horizontal COR was median 1.4 mm (interquartile range (IQR) 0.87 to 3.42) in RO THA versus 4.3 mm (IQR 3 to 6.8; p < 0.001); vertical COR mean 0.91 mm (SD 0.73) in RO THA versus 2.3 mm (SD 1.3; p < 0.001); and combined offset median 2 mm (IQR 0.97 to 5.45) in RO THA versus 3.9 mm (IQR 2 to 7.9; p = 0.019). Improved accuracy was observed with RO THA in achieving the desired acetabular component positioning (root mean square error for anteversion and inclination was 2.6 and 1.3 vs 8.9 and 5.3, repectively) and leg length (mean 0.6 mm vs 1.4 mm; p < 0.001). Patient-reported outcome measures were comparable between the two groups at baseline and one year. Participants in the RO THA group needed fewer physiotherapy sessions postoperatively (median six (IQR 4.5 to 8) vs eight (IQR 6 to 11; p = 0.005). Conclusion: This RCT suggested that robotic-arm assistance in THA was associated with improved accuracy in restoring the native COR, better preservation of the combined offset, leg length correction, and superior accuracy in achieving the desired acetabular component positioning. Further evaluation through long-term and registry data is necessary to assess whether these findings translate into improved implant survival and functional outcomes.

Early clinical and radiological outcomes of the new porous titanium shell in combination with locking screw in revision total hip arthroplasty.

INTRODUCTION: Extensive acetabular bone loss and poor bone quality are two key challenges often encountered in revision total hip arthroplasty. A new 3D-printed porous acetabular shell has been made available with the option to insert multiple variable-angle locking screws. We sought to evaluate the early clinical and radiological outcomes of this construct. METHODS: A retrospective review of patients operated by two surgeons was performed in a single institution. Fifty-nine revision hip arthroplasties were performed in 55 patients (34 female; mean age 68.8 ± 12.3 years) for Paprosky defects I (n = 21), IIA/B (n = 22), IIC (n = 9), III (n = 7) between February 2018 and January 2022 using the novel porous titanium acetabular shell and multiple variable angle locking screws. Postoperative clinical and radiographic outcomes were locally maintained. Patient-reported outcome measures collected included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Oxford Hip Score, and the 12-item Short Form Survey. RESULTS: After a mean follow-up of 25.7 ± 13.9 months, two cases of shell migration were noted. One patient had a failed constrained mechanism and received revision to a cemented dual mobility liner. No other acetabular shells showed any evidence of radiographic loosening at the final follow-up. Preoperatively, 21 defects were classified as Paprosky grade I, 19 grade IIA, 3 grade IIB, 9 IIC, 4 grade IIIA, and 3 IIIB. The mean postoperative WOMAC function score was 84 (SD 17), WOMAC (stiffness) 83 (SD 15), WOMAC (pain) 85 (SD 15), and WOMAC (global) 85 (SD 17). The mean postoperative OHS was 83 (SD 15), and mean SF-12 physical score was 44 (SD 11). CONCLUSION: The additional augmentation of porous metal acetabular shells with multiple variable-angle locking screws provides reliable initial fixation with good clinical and radiological outcomes in the short term. Further studies are needed to establish the medium- and long-term outcomes. LEVEL OF EVIDENCE: IV.

Inflammatory Response in Robotic-Arm-Assisted Versus Conventional Jig-Based TKA and the Correlation with Early Functional Outcomes: Results of a Prospective Randomized Controlled Trial.

BACKGROUND: Although the exact etiology of patient dissatisfaction in total knee arthroplasty (TKA) is unclear, the inflammatory response precipitated by surgery may be implicated. Robotic TKA has been shown to result in reduced bone and soft-tissue trauma. The objectives of this study were to compare the inflammatory response in conventional jig-based TKA versus robotic-arm-assisted TKA and to examine the relationship with early functional outcomes. METHODS: This prospective randomized controlled trial included 15 patients with symptomatic knee osteoarthritis undergoing conventional TKA and 15 undergoing robotic-arm-assisted TKA. Blood samples were collected for up to 28 days postoperatively, and predefined markers of systemic inflammation were measured in serum. The local inflammatory response was assessed by analyzing samples from the intra-articular drain fluid at 6 and 24 hours. Relationships with early functional outcomes were evaluated using the Spearman rank correlation coefficient. RESULTS: Patients in the robotic TKA group demonstrated lower levels of interleukin (IL)-6 in the drain fluid at 6 hours (798.54 pg/mL versus 5,699.2 pg/mL, p = 0.026) and 24 hours and IL-8 at 6 hours. Robotic TKA was associated with lower pain scores on postoperative days 1, 2, and 7. Patient-reported outcome measures were comparable between the 2 groups at 2 years. Significant correlations were observed between all serum markers except IL-1b and self-reported pain on postoperative day 7; between drain IL-8 levels and pain on postoperative days 1 (r = 0.458), 2, and 7; and between drain IL-6, IL-8, and tumor necrosis factor-alpha levels at 6 hours and knee flexion or extension. CONCLUSIONS: Robotic-arm-assisted TKA was associated with a reduction in the early postoperative local inflammatory response. We also found a moderate relationship between the inflammatory responses and self-reported pain, knee flexion, and knee extension. Further validation of these findings on a larger scale and using longer-term outcomes will be key to developing the optimal TKA procedure. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Extended trochanteric osteotomy in revision hip arthroplasty: a case series study and systematic literature review.

BACKGROUND: Extended trochanteric osteotomy (ETO) in revision hip arthroplasty provides direct access to the femoral medullary canal and facilitates removal of implants and re-implantation. This study looks at objective outcomes of ETO from a systematic review of the literature and a case series of revision total hip arthroplasty (THA) cases with ETOs from the authors' local institution. METHODS: (1) The National Institutes of Health (NIH) national library of medicine was searched for studies related to ETO and the preferred reporting items for systematic reviews and meta-analyses (PRISMA) technique were followed. (2) Case series of 23 revision THAs with ETOs from University College London Hospital (UCLH) were retrospectively analyzed with a minimum of 2-year follow-up for radiological outcomes. RESULTS: (1) The main revision THAs diagnoses were aseptic loosening (880/1,386; 63.4%), prosthetic joint infection (PJI) (301/1,386; 21.7%) and periprosthetic THA fractures (78/1,386; 5.6%). Other diagnoses, including non-specified reasons for THA revision in the chosen studies, accounted for 9.2% (127/1,386). The total mean was a union rate of 95.2%, an infection eradication rate of 91.6%, a femoral stem subsidence rate of 16.6%, with the rate of subsidence more than 5 mm being 10.7%. ETO proximal migration was reported in 7.8% of ETOs; however, it rarely required re-attachment (0.9%). Intraoperative fracture during revision THA with ETO was reported to be at a rate of 5%; while postoperative femoral fracture rate was at 7.8%. (2) All 24 cases had radiographic union at 3 to 6 months and there was no reported femoral stem subsidence. CONCLUSION: The overall outcome of this literature review provides moderate-quality evidence indicating that ETO provides safe outcome for revision THAs in single and 2-stage revision surgeries with low ETO non-union, femoral stem subsidence, greater trochanter (GT) proximal migration and fracture rates in the different diagnoses groups of revision THA at over 2-year follow up. In the case series group, there was radiographic union of all ETOs with no reported femoral stem subsidence or periprosthetic fractures.

Metaphyseal fixation in revision knee arthroplasty: a systematic review of the literature and meta-analysis of mid-long-term outcomes of metaphyseal sleeves and cones.

Metaphyseal augmentation has in recent years formed a key strategy in management of bone loss in revision knee arthroplasty. There are studies reporting excellent short-term results, however long- term data is lacking. There is also a paucity of studies comparing the most frequently utilised augments, metaphyseal sleeves, and cones. We conducted a systematic review and meta-analysis to evaluate and compare the mid to long term outcomes of metaphyseal cones and sleeves. We conducted systematic search of 4 databases (Medline, Embase, CINALH and PubMed). Seventeen studies were found to be eligible for inclusion of which ten investigated metaphyseal sleeves and the remaining seven investigated cones. Mean follow up across all studies was 6.2 years. The total number of patients included in the studies was 1319 and the number of knees operated on was 1431. We noted a higher revision rate of metaphyseal cones when compared to sleeves 10.85% vs 6.31 (p=0.007). Reoperation rates were also higher in cones compared to sleeves, 13.78% vs 3.68% (p<0.001). Prosthetic joint infection was the most common reason for revision. The difference in conversion rates, based on augment location was statistically significant p=0.019. When undertaking further sub-analysis; there was no statistically significant difference when comparing revision rates of; tibial vs femoral augments p=0.108, tibial vs tibial & femur p=0.54 but a difference was seen between femoral vs tibial & femoral augments p=0.007. Based on our data, metaphyseal sleeves demonstrate significantly lower revision rates compared to metaphyseal cones. However overall, both demonstrate reliable mid to long-term outcomes.

The outcomes of surgical management of failed two-stage revision knee arthroplasty.

Background Joint infection following total knee arthroplasty has significant consequences on both the patient and healthcare system. Two stage revision arthroplasties is viewed as the gold standard in management. However, recurrence of infection following this procedure is a growing clinical problem for a multitude of reasons. Despite a variety of surgical options for management of failure of two-stage revision arthroplasty, the potential for complications and functional limitation remains high, and the optimal strategy is yet to be determined. Methods We performed a systematic review of all papers reporting on the outcomes of the surgical management of failure of two-stage revision arthroplasty published up to and including January 2020. Data was extracted on patient demographics, study design, methodological quality, indication for surgery, surgical technique, clinical and functional outcomes, and complications. Results Nine papers with a total of 273 patients were found and analysed All surgical techniques had mixed results in term of clinical and functional outcomes, and the rate of complications was high in all studies. Knee arthrodesis had the lower risk of failure than repeat 2 stage revision. Poor patient immunological status and limb status were weakly associated with increased risk of failure. Conclusion Despite failure of two-stage revision arthroplasty being a growing clinical issue, we were not able to identify any consistently superior surgical technique for the management of this scenario. Knee arthrodesis appears to provide the best results for improving quality of life and reducing infection recurrence, although the complication rate is high and the functional outcomes appear to be worse. Further larger and prospective studies are needed to elucidate optimal surgical management in different patient subsets.

The majority of conversion total hip arthroplasties can be considered primary replacements - a matched cohort study.

The success of conversion Total Hip Arthroplasty (THA) among primary THA and revision THA re- mains unclear. We hypothesized that most conversion THAss can be performed using primary implants and will have an uncomplicated post-operative course. Thirty-six patients (23 females, mean age 68,0y) who underwent conversion THA for failed interventions for proximal femur fractures in the period 2006-2018 were matched sequentially against patients of the same sex and age who underwent primary THA or revision THA. Data was collected on implants used, major complications, and mortality. PROMs used included the Western Ontario and McMaster Osteoarthritis Index, Harris Hip Score, Visual Analogue Scale and the EQ-5D Health Questionnaire. Seventy- two percent of patients who underwent conversion THA were treated with primary implants and never suffered from a major complication. PROMs were excellent for this group of patients. The distinction primary / conversion / revision THA could not explain differences in outcomes, however the necessity of using revision implants and the development of major complications could. The majority of conversion total hip arthroplasties can be considered a primary replacement. Predicting outcomes for THA should focus on patient frailty and technical difficulties dealing with infection, stability and loss of bone stock and should discard the conversion versus revision terminology.

Day-case total hip arthroplasty: a literature review and development of a hospital pathway.

AIMS: We present the development of a day-case total hip arthroplasty (THA) pathway in a UK National Health Service institution in conjunction with an extensive evidence-based summary of the interventions used to achieve successful day-case THA to which the protocol is founded upon. METHODS: We performed a prospective audit of day-case THA in our institution as we reinitiate our full capacity elective services. In parallel, we performed a review of the literature reporting complication or readmission rates at ≥ 30-day postoperative following day-case THA. Electronic searches were performed using four databases from the date of inception to November 2020. Relevant studies were identified, data extracted, and qualitative synthesis performed. RESULTS: Our evaluation and critique of the evidence-based literature identifies day-case THA to be safe, effective, and economical, benefiting both patients and healthcare systems alike. We further validate this with our institutional elective day surgery arthroplasty pathway (EDSAP) and report a small cohort of successful day-case THA cases as an example in the early stages of this practice in our unit. CONCLUSION: Careful patient selection and education, adequate perioperative considerations, including multimodal analgesia, surgical technique and blood loss management protocols and appropriate postoperative pathways comprising reliable discharge criteria are essential for successful day-case THA. Cite this article: Bone Jt Open 2021;2(2):93-102.

Early clinical and radiological outcomes of a new tapered fluted titanium monobloc revision stem in hip arthroplasty.

PURPOSE: A new fluted, titanium, monobloc stem with a three degree taper has been designed in an attempt to overcome the challenges associated with femoral reconstruction in the setting of extensive bone loss. The aim of this study was to report its early clinical and radiographic outcomes. METHODS: This is a retrospective review of prospectively collected data carried out at a single institution between Jan 2017 and Dec 2019. Forty-three femoral revisions were performed using a new tapered, fluted, titanium, monobloc (TFTM) revision stem. Complications, clinical and radiographic data were obtained from medical records and a locally maintained database. Clinical outcomes were assessed using the Oxford Hip Score (OHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). All post-operative radiographs were analysed for subsidence, osteolysis and femoral cortical bone remodelling. RESULTS: Mean follow-up was 24 months (range 8-42 months). Subsidence of 1.2 mm was noted in one patient. No cases of clinically significant subsidence (> 10 mm) were observed. At final follow-up, a statistically significant improvement was noted in functional outcome scores. The mean OHS preoperatively and at final follow-up were 24 (SD 13) and 42 (SD15). p = 0.04 mean difference 18 (95% CI 15-22). The mean WOMAC scores preoperatively and at final follow-up were 62 (SD23) and 88 (SD7) respectively (p < 0.001, mean difference 26; 95% CI 21-34). No stem fractures were noted within the follow-up period. CONCLUSION: Positive early clinical and radiological outcomes have been observed with this tapered, fluted, titanium, monobloc stem. Based on these results, this implant may be considered as a viable option in the majority of uncemented femoral revisions.

The learning curve of robotic-arm assisted acetabular cup positioning during total hip arthroplasty.

BACKGROUND: Robotic-arm assisted surgery aims to reduce manual errors and improve the accuracy of implant positioning and orientation during total hip arthroplasty (THA). The objective of this study was to assess the surgical team's learning curve for robotic-arm assisted acetabular cup positioning during THA. METHODS: This prospective cohort study included 100 patients with symptomatic hip osteoarthritis undergoing primary total THA performed by a single surgeon. This included 50 patients receiving conventional manual THA and 50 patients undergoing robotic-arm assisted acetabular cup positioning during THA. Independent observers recorded surrogate markers of the learning curve including operative times, confidence levels amongst the surgical team using the state-trait anxiety inventory (STAI) questionnaire, accuracy in restoring native hip biomechanics, acetabular cup positioning, leg-length discrepancy, and complications within 90 days of surgery. RESULTS: Cumulative summation (CUSUM) analysis revealed robotic-arm assisted acetabular cup positioning during THA was associated with a learning curve of 12 cases for achieving operative times (p < 0.001) and surgical team confidence levels (p < 0.001) comparable to conventional manual THA. There was no learning curve of robotic-arm assisted THA for accuracy of achieving the planned horizontal (p = 0.83) and vertical (p = 0.71) centres of rotation, combined offset (p = 0.67), cup inclination (p = 0.68), cup anteversion (p = 0.72), and correction of leg-length discrepancy (p = 0.61). There was no difference in postoperative complications between the two treatment groups. CONCLUSIONS: Integration of robotic-arm assisted acetabular cup positioning during THA was associated with a learning curve of 12 cases for operative times and surgical team confidence levels but there was no learning curve effect for accuracy in restoring native hip biomechanics or achieving planned acetabular cup positioning and orientation.

Mid-term results of a prospective randomised controlled trial comparing large-head metal-on-metal hip replacement to hip resurfacing using patient-reported outcome measures and objective functional task-based outcomes.

BACKGROUND: The early outcomes of large head-metal-on-metal total hip arthroplasty (MoM THA) are compromised by adverse local tissue reaction to metal debris. This study is the mid-term follow-up of a prospective randomised control trial (pRCT) comparing MoM THA to MoM HR. We sought to answer whether there was a difference between MoM THA and MoM HR at mid-term follow-up in the implant survival; patient-reported outcome measures (PROMs); and when performing objective functional tasks? METHODS: A total of 104 patients were studied. Of these 56 had MoM THA (50 male) and 48 had HR (43 male). Mean age at surgery was 52 years in both groups.We reviewed this cohort at mid-term follow-up [minimum 8 years (mean 9 years; range 8-10; SD 0.7)]. PROMs that were completed were OHS, WOMAC, SF-12, and the UCLA. For objective functional task-based outcomes, gait parameters for operated legs were assessed in a subgroup of 17 patients with high UCLA. RESULTS: Revision rate in MoM THA group was 7/56 (12.5%) and in the HR group was 1/48 (2.1%). Overall revision rate at minimum 8-year follow-up was 7.7% (8 of 104 patients). PROMs data comparing MoM THA versus HR showed no difference between the groups. 4 (8.5%) of the non-revised (47) HR patients had WOMAC function or pain score below 70. 3 (6.4%) patients had both pain and function scores <70. In the THA group, 5 (10.2%) of the non-revised (49) patients had WOMAC pain or function scores <70. 3 (6.1%) patients had both pain and function scores <70. The comparison of HA versus THA showed several gait parameters in the HR group to be better but not statistically significant (p > 0.05 Mann-Whitney U-test). CONCLUSIONS: At mid-term follow-up, the revision rate of MoM articulation for THA is high (7.7%), being higher in large head MoM total hips versus resurfacing. Overall probability of 10-year survival is 92.3% (KM analysis, 95% for MoM THA and 98% for HR). The HR group had better functional parameters on gait-based tasks compared to THA group but this difference did not reach statistical significance.

A prospective randomized controlled trial comparing the systemic inflammatory response in conventional jig-based total knee arthroplasty versus robotic-arm assisted total knee arthroplasty.

AIMS: The primary aim of this study was to compare the postoperative systemic inflammatory response in conventional jig-based total knee arthroplasty (conventional TKA) versus robotic-arm assisted total knee arthroplasty (robotic TKA). Secondary aims were to compare the macroscopic soft tissue injury, femoral and tibial bone trauma, localized thermal response, and the accuracy of component positioning between the two treatment groups. METHODS: This prospective randomized controlled trial included 30 patients with osteoarthritis of the knee undergoing conventional TKA versus robotic TKA. Predefined serum markers of inflammation and localized knee temperature were collected preoperatively and postoperatively at six hours, day 1, day 2, day 7, and day 28 following TKA. Blinded observers used the Macroscopic Soft Tissue Injury (MASTI) classification system to grade intraoperative periarticular soft tissue injury and bone trauma. Plain radiographs were used to assess the accuracy of achieving the planned postioning of the components in both groups. RESULTS: Patients undergoing conventional TKA and robotic TKA had comparable changes in the postoperative systemic inflammatory and localized thermal response at six hours, day 1, day 2, and day 28 after surgery. Robotic TKA had significantly reduced levels of interleukin-6 (p < 0.001), tumour necrosis factor-α (p = 0.021), ESR (p = 0.001), CRP (p = 0.004), lactate dehydrogenase (p = 0.007), and creatine kinase (p = 0.004) at day 7 after surgery compared with conventional TKA. Robotic TKA was associated with significantly improved preservation of the periarticular soft tissue envelope (p < 0.001), and reduced femoral (p = 0.012) and tibial (p = 0.023) bone trauma compared with conventional TKA. Robotic TKA significantly improved the accuracy of achieving the planned limb alignment (p < 0.001), femoral component positioning (p < 0.001), and tibial component positioning (p < 0.001) compared with conventional TKA. CONCLUSION: Robotic TKA was associated with a transient reduction in the early (day 7) postoperative inflammatory response but there was no difference in the immediate (< 48 hours) or late (day 28) postoperative systemic inflammatory response compared with conventional TKA. Robotic TKA was associated with decreased iatrogenic periarticular soft tissue injury, reduced femoral and tibial bone trauma, and improved accuracy of component positioning compared with conventional TKA. Cite this article: Bone Joint J 2021;103-B(1):113-122.

Clinical and Health-Care Cost Analysis of Negative Pressure Dressing in Primary and RevisionTotal Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: Negative pressure wound therapy (NPWT) has been used because of its perceived advantages in reducing surgical site infections, wound complications, and the need for further surgery. The purpose of this study was to assess the infection rates, wound complications, length of stay, and financial burden associated with NPWT use in primary and revision total knee arthroplasty (TKA). METHODS: We performed a PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) systematic review of the existing literature on using NPWT in primary and revision TKA. PubMed, Embase, Science Direct, and the Cochrane Library were utilized. The risk of bias was evaluated using the ROBINS-I (Risk Of Bias In Non-randomised Studies - of Interventions) tool, and the quality of evidence was evaluated using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. RESULTS: Twelve articles that evaluated 1,403 primary TKAs and 279 revision TKAs were reviewed. NPWT significantly reduced complication rates in revision TKA. However, there was no significant difference in infection rates between NPWT and regular dressings in primary or revision TKA. NPWT use in primary TKA significantly increased the risk of blistering, although no increase in reoperations was noted. The analysis showed a possible reduction in length of stay associated with NPWT use for both primary and revision TKA, with overall health-care cost savings. CONCLUSIONS: Based on a meta-analysis of the existing literature, we do not recommend the routine use of NPWT. However, in high-risk revision TKA and selected primary TKA cases, NPWT reduced wound complications and may have health-care cost savings. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Computerised tomography-based planning with conventional total hip arthroplasty versus robotic-arm assisted total hip arthroplasty: study protocol for a prospective randomised controlled trial.

BACKGROUND: Robotic-arm assisted surgery aims to reduce manual errors and improve the accuracy of implant positioning during total hip arthroplasty. The objective of this study is to compare the accuracy of implant positioning, restoration of hip biomechanics, patient satisfaction, functional outcomes, implant survivorship, cost-effectiveness, and complications in conventional manual total hip arthroplasty (CO THA) versus robotic-arm assisted total hip arthroplasty (RO THA). Preoperative pelvic computerised tomography (CT) scans will be used to create patient-specific, virtual, three-dimensional reconstructions for surgical planning in both treatment groups. METHODS AND ANALYSIS: This prospective randomised controlled trial will include 60 patients with symptomatic hip osteoarthritis undergoing primary THA. Following informed consent, patients will be randomised to CO THA (control group) or RO THA (investigation group) at a ratio of 1:1 using an online random number generator. Observers will review patients at regular intervals for 2 years after surgery to record predefined study outcomes relating to the accuracy of implant positioning, hip biomechanics, postoperative rehabilitation, clinical progress, functional outcomes, cost-effectiveness, and complications. Primary and secondary objectives will be used to quantify and draw inferences on differences in the efficacy of treatment between the two groups. Intention-to-treat and per-protocol population analysis will be undertaken. Intention to treat relates to the allocated treatment (CO THA or RO THA), and per-protocol refers to the actual treatment received by the patient. The following statistical methods will be employed to analyse the data: descriptive statistics, independent t test, paired t test, analysis of variance, Fisher exact test, chi-square test, and graphical displays. Ethical approval was obtained from the London-Bromley Research Ethics Committee, UK. The study is sponsored by University College London, UK. DISCUSSION: This study compares a comprehensive and robust range of clinical, functional, and radiological outcomes in CT-planned CO THA versus CT-planned RO THA. The findings of this study will enable an improved understanding of the differences in CO THA versus RO THA with respect to patient satisfaction, functional outcomes, implant survivorship, cost-effectiveness, and complications. TRIAL REGISTRATION: ClinicalTrials.gov NCT04095845 . Registered on 19 September 2019.

Does Multimodal Therapy Influence Functional Outcome After Total Knee Arthroplasty?

Psychosocial health may influence the outcomes after total knee arthroplasty (TKA). We investigated the hypothesis that multimodal therapy influences the quality of life and function in patients diagnosed with osteoarthritis of the knee joint. Secondly, in patients who then proceed to have TKA post-multimodal therapy, does the response to the multimodal therapy influence the overall functional outcome of surgery? Patients diagnosed with osteoarthritis of the knee were enrolled in the study and prospectively followed-up. A total of 526 patients were enrolled and available for the study. All participants were enrolled for 12 classes of 60-minute duration over 6-weeks. Apart from an exercise program, the class also included physiotherapist-led education and a 'weight management' lecture by a dietitian. In summary, the multimodal therapy program improved the SF-12, OKS, pain scores (visual analogue scale) and WOMAC scores significantly. The multimodal therapy protocol can optimize patients' psychological scores prior to TKA and may enhance ultimate functional outcome.

Robotic-arm assisted medial unicondylar knee arthroplasty versus jig-based unicompartmental knee arthroplasty with navigation control: study protocol for a prospective randomised controlled trial.

BACKGROUND: There remains a paucity of clinical studies assessing how any differences in accuracy of implant positioning between robotic-arm assisted unicompartmental knee arthroplasty (RO UKA) and conventional jig-based unicompartmental knee arthroplasty (CO UKA) translate to patient satisfaction, functional outcomes, and implant survivorship. The objectives of this study are to compare accuracy of implant positioning, limb alignment, patient satisfaction, functional outcomes, implant survivorship, cost-effectiveness, and complications in CO UKA versus RO UKA. Computer navigation will be used to assess intraoperative knee kinematics in all patients undergoing CO UKA. METHODS AND ANALYSIS: This prospective randomised controlled trial will include 140 patients with symptomatic medial compartment knee arthritis undergoing primary UKA. Following informed consent, patients will be randomised to CO UKA (control group) or RO UKA (investigation group) at a ratio of 1:1 using an online random number generator. The primary objective of this study is to compare accuracy of implant positioning in CO UKA versus RO UKA. The secondary objectives are to compare the following outcomes between the two treatment groups: limb alignment, surgical efficiency, postoperative functional rehabilitation, functional outcomes, quality of life, range of motion, resource use, cost effectivness, and complications. Observers will review patients at regular intervals for 2 years after surgery to record predefined study outcomes pertaining to these objectives. Ethical approval was obtained from the London-Bloomsbury Research Ethics Committee, UK. The study is sponsored by University College London, UK. DISCUSSION: This study compares a comprehensive and robust range of clinical, functional, and radiological outcomes in CO UKA versus RO UKA. The findings of this study will provide an improved understanding of the differences in CO UKA versus RO UKA with respect to accuracy of implant positioning, patient satisfaction, functional outcomes, implant survivorship, cost-effectiveness, and complications. TRIAL REGISTRATION: ClinicalTrials.gov NCT04095637 . Registered on 19 September 2019.

Access to hip and knee replacement surgery in patients with chronic diseases according to patient-reported pain and functional status.

BACKGROUND: An increasing number of patients undergoing hip or knee replacement have chronic diseases. It has been suggested that the presence of chronic diseases may affect access to this type of surgery in the English National Health Service (NHS). We examined the access to hip and knee replacement surgery in patients with and without chronic diseases according to preoperative patient-reported pain, functional status and symptom duration. METHODS: We analysed data of 640,832 patients who had hip or knee surgery between 2009 and 2016 in England. Multivariable regression was used to estimate the impact of 11 chronic diseases on severity of joint problems as measured on a scale from 0 to 48 by Oxford Hip (OHS) and Knee Scores (OKS) just before surgery and on likelihood of long-standing joint problems (> 5 years pre-operatively). RESULTS: Patients with chronic diseases reported more severe joint problems than patients without (OHS differences ranged from 1.1 [95% CI 0.93, 1.2] to 2.5 [95% CI 2.3, 2.7] and OKS differences from 0.5 [95% CI 0.3, 0.7] to 2.6 [95% CI 2.4, 2.7] for the 11 chronic diseases) but the differences remain small. When analysed separately, patients with chronic diseases reported both more severe pain and poorer functional status. Six chronic diseases in hip patients and two in knee patients increased the likelihood that they had long-standing joint problems. The severity of joint problems just before surgery increased with the number of chronic diseases (OHS differences; one chronic disease (1.5 [95% CI 1.4, 1.5]) to four or more (5.8 [95% CI 5.6, 6.0])). CONCLUSIONS: Patients with chronic diseases reported more severe joint problems immediately before hip or knee replacement surgery suggesting they have hip or knee replacement later in the course of their joint disease.

The direct superior approach versus posterior approach for total hip arthroplasty: study protocol for a prospective double-blinded randomised control trial.

BACKGROUND: The direct superior approach (DSA) is a minimally invasive modification of the posterior approach (PA) that preserves the iliotibial band and short external rotators except for the piriformis or conjoint tendon during total hip arthroplasty (THA). The objective of this study is to compare patient satisfaction, functional outcomes, accuracy of implant positioning, component stability, gait, cost-effectiveness, and complications in the DSA versus PA for THA. METHODS AND ANALYSIS: This prospective double-blinded randomised control trial will include 80 patients with symptomatic hip osteoarthritis undergoing primary THA. Following informed consent, patients will be randomised to THA using the PA (control group) or DSA (investigation group) at a ratio of 1:1 using an online random number generator. Blinded observers will review patients at regular intervals for 2 years after surgery to record predefined study outcomes relating to postoperative rehabilitation, clinical progress, functional outcomes, accuracy of implant positioning, gait analysis on force plate treadmill, implant migration with radiosteriometric analysis, cost-effectiveness, and complications. A superiority study design will be used to evaluate whether the DSA provides improved outcomes compared to the PA for THA. Evaluation of study outcomes in DSA and PA will be used to quantify and draw inferences on differences in the efficacy of treatment between the two groups. Intention-to-treat and per-protocol population analysis will be undertaken. The following statistical methods will be employed to analyse the data: descriptive statistics, independent t test, paired t test, analysis of variance, Fisher exact test, chi-square test, and graphical displays. Ethical approval was obtained from the London-Fulham Research Ethics Committee, UK. The study is sponsored by University College London, UK. DISCUSSION: This study compares a comprehensive and robust range of clinical, functional, and radiological outcomes in THA performed using the PA versus DSA. The findings of this study will provide an improved understanding of the differences in the PA versus DSA for THA with respect to patient satisfaction, functional outcomes, implant survivorship, gait, cost-effectiveness, and complications. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04191993. Registered on 10 December 2019.

The effect of anterior cruciate ligament resection on knee biomechanics.

AIMS: The objectives of this study were to assess the effect of anterior cruciate ligament (ACL) resection on flexion-extension gaps, mediolateral soft tissue laxity, maximum knee extension, and limb alignment during primary total knee arthroplasty (TKA). METHODS: This prospective study included 140 patients with symptomatic knee osteoarthritis undergoing primary robotic-arm assisted TKA. All operative procedures were performed by a single surgeon using a standard medial parapatellar approach. Optical motion capture technology with fixed femoral and tibial registration pins was used to assess study outcomes pre- and post-ACL resection with knee extension and 90° knee flexion. This study included 76 males (54.3%) and 64 females (45.7%) with a mean age of 64.1 years (SD 6.8) at time of surgery. Mean preoperative hip-knee-ankle deformity was 6.1° varus (SD 4.6° varus). RESULTS: ACL resection increased the mean extension gap significantly more than the flexion gap in the medial (mean 1.2 mm (SD 1.0) versus mean 0.2 mm (SD 0.7) respectively; p < 0.001) and lateral (mean 1.1 mm (SD 0.9) versus mean 0.2 mm (SD 0.6) respectively; p < 0.001) compartments. The mean gap differences following ACL resection did not create any significant mediolateral soft tissue laxity in extension (gap difference: mean 0.1 mm (SD 2.4); p = 0.89) or flexion (gap difference: mean 0.2 mm (SD 3.1); p = 0.40). ACL resection did not significantly affect maximum knee extension (change in maximum knee extension = mean 0.2° (SD 0.7°); p = 0.23) or fixed flexion deformity (mean 4.2° (SD 3.2°) pre-ACL release versus mean 3.9° (SD 3.7°) post-ACL release; p = 0.61). ACL resection did not significantly affect overall limb alignment (change in alignment = mean 0.2° valgus (SD 1.0° valgus; p = 0.11). CONCLUSION: ACL resection creates flexion-extension mismatch by increasing the extension gap more than the flexion gap. However, gap differences following ACL resection do not create any mediolateral soft tissue laxity in extension or flexion. ACL resection does not affect maximum knee extension or overall limb alignment. Cite this article: Bone Joint J 2020;102-B(4):442-448.