The primary aim is to estimate the current and potential number of patients on NHS England orthopaedic elective waiting lists by November 2020. The secondary aims are to model recovery strategies; review the deficit of hip and knee arthroplasty from National Joint Registry (NJR) data; and assess the cost of returning to pre-COVID-19 waiting list numbers. A model of referral, waiting list, and eventual surgery was created and calibrated using historical data from NHS England (April 2017 to March 2020) and was used to investigate the possible consequences of unmet demand resulting from fewer patients entering the treatment pathway and recovery strategies. NJR data were used to estimate the deficit of hip and knee arthroplasty by August 2020 and NHS tariff costs were used to calculate the financial burden.Aims
Methods
The primary aim was to assess the rate of patient deferral of elective orthopaedic surgery and whether this changed with time during the coronavirus disease 2019 (COVID-19) pandemic. The secondary aim was to explore the reasons why patients wanted to defer surgery and what measures/circumstances would enable them to go forward with surgery. Patients were randomly selected from elective orthopaedic waiting lists at three centres in the UK in April, June, August, and September 2020 and were contacted by telephone. Patients were asked whether they wanted to proceed or defer surgery. Patients who wished to defer were asked seven questions relating to potential barriers to proceeding with surgery and were asked whether there were measures/circumstances that would allow them to go forward with surgery.Aims
Methods
Osteonecrosis may be triggered by bone temperature above 45°C during routine orthopaedic bone cuts using power-driven saws, with potentially negative impacts on bone healing. A new oscillating-tip saw blade design (Precision; Stryker, Kalamazoo, Mich) has been recently developed but the saw blade design may influence the amount of heat generated. We have therefore sought to compare the bone temperature during a standardised cutting task with two different saw blade designs. Three pairs of human cadaveric femora were obtained. Each femur was clamped and a distal femoral cutting jig was applied. An initial cut was performed to visualise the distal metaphyseal bone. The cutting block was then moved 2 mm proximal and a further cut performed, measuring the temperature of the bone with an infra-red camera. This was repeated, moving the block 2 mm proximal with each cut, alternating between a standard oscillating saw blade and the “Precision” saw blade. The density of the cut bone was then established from a CT scan of each specimen performed prior to the experiment.Introduction & aims
Method
Patient-matched instrumentation is advocated as the latest development in arthroplasty surgery. Custom-made cutting blocks created from preoperative MRI scans have been proposed to achieve perfect alignment of the lower limb in total knee arthroplasty (TKA). The aim of this study was to determine the efficacy of patient-specific cutting blocks by comparing them to navigation, the current gold standard. 60 TKA patients were recruited to undergo their surgery guided by Smith & Nephew Visionaire Patient-Matched cutting blocks. Continuous computer navigation was used during the surgery to evaluate the accuracy of the cutting blocks. The blocks were assessed for the fit to the articular surface, as well as alignment in the coronal, sagittal and rotational planes, sizing, and resection depth.Purpose
Methods
Peri-prosthetic infection remains a leading cause
of revision surgery. Recent publications from the American Musculoskeletal
Infection Society have sought to establish a definition of peri-prosthetic
infection based on clinical findings and laboratory investigations.
The limitations of their approach are discussed and an alternative
definition is proposed, which it is felt may better reflect the
uncertainties encountered in clinical practice.
Computer navigation has been shown to improve the accuracy of total knee replacement (TKR) when compared to intra or extra osseous referencing. Currently the surgical transepicondylar axis (TEA) is used to help determine femoral component rotation. This relies on the surgeon identifying medial and lateral epicondyles intra-operatively. This process has been shown to have a high variability and operator dependency. The functional flexion axis (FFA) of the femur is a kinematically derived reference axis which has previously been shown in a cadaveric model to correspond well with the transepicondylar axis. This study was therefore designed to evaluate its accuracy in vivo. 50 patients undergoing total knee replacement under the care of the three senior authors were prospectively recruited. A preoperative CT scan was obtained and the TEA evaluated by 2 independent clinicians. TKR was undertaken in the standard fashion using Stryker navigation. The FFA was derived at 3 time points during the procedure: pre-incision, post osseous registration and following component implantation. The deviations of the FFA and surgical TEA (surTEA) to the CT-derived TEA (ctTEA) was calculated and comparisons drawn between the 2 methods with respect to validity, as well as within and between-patient reproducibility. While the FFA results were highly correlated between pre and post-arthrotomy (r = 0.89), the post-incision FFA (−1.60+/−3.7) was significantly internally rotated (p<0.01) relative to the pre-incision FFA (−2.50+/−3.4). In addition the surgical TEA (−0.40+/−3.6) was significantly internally rotated (p = 0.02) relative to the post-incision FFA (1.80+/−3.7) for the combined data from all 2 surgeons. However, when examined individually, 1 of the 2 surgeons showed no significant difference between the FFA and TEA. In addition, the two methods demonstrated comparable between-patient variability in the knee axis, although surgeon-dependent patterns remained. The FFA has been shown to be of equivalent accuracy to the surgical TEA but surprisingly does not avoid its operator-dependency. Further evaluation of the FFA method with possible adjustments to the algorithm is warranted.
Computer assisted surgical navigation has played an increasingly central role in total knee arthroplasty (TKA). Given the recognized importance of subtle component position changes in knee function, navigation has emerged as a promising tool for reducing the occurrence of significant malalignment. The ability of this technology to reliably measure multiple parameters intraoperatively allows analysis to possibly identify a correlation between intraoperative computer assisted surgical navigation data and functional outcomes of patients undergoing elective total knee arthroplasty. Intraoperative navigation data was collected for 121 patients undergoing cemented, posterior stabilized TKA. Three forward stepwise regression analyses were performed to associate intraoperative coronal alignment correction, tibiofemoral external rotation, and alignment under varus and valgus stress with one year outcomes, including range of motion, Oxford and SF-36 scores. The amount of alignment correction and the maximum flexion achieved intraoperatively were significantly correlated (p <0.05, R-sq = 13%) with clinically measured maximum flexion at one year. Maximum flexion achieved intraoperatively, external tibiofemoral rotation and maximum varus under stress were also significantly associated (p < 0.05, R-sq = 31%) with the physical component of the SF-36 outcome score. Analyses of computer navigation in TKA to date have primarily focused on precision of sagittal plane correction. Alternatively we have identified four intraoperative parameters that correlate with functional outcome at one year. Correct intraoperative interpretation of navigation data may allow surgeons to make subtle changes in real time to produce superior short-term outcomes for patients.
