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Introduction: Osteotomy of the distal femur (DFO) to address symptomatic degeneration in the knee is a well-established procedure with good results reported in the literature . Broadly the osteotomy is based on either an opening or a closing wedge alignment technique. Several patient related parameters including age, gender, body mass index (BMI) and surgical factors such as osteotomy site, gap, and fixation technique amongst others have been demonstrated to influence the outcome of DFO. Preoperative planning based on imaging is vital to assess the type and extent of deformity correction to be undertaken in order to achieve optimal alignment. Computer-assisted surgery (CAS) has been extensively used as dynamic intraoperative alignment aid in knee arthroplasty providing good outcomes. Several investigators in the current literature have utilised computer navigation in proximal tibial osteotomy and reported improved accuracy in realising the planned alignment. However there is paucity of studies reporting the long-term outcomes of distal femur lateral opening-wedge (DFLOWO) using computer navigation. Through our study we aim to report on the long-term outcomes and survivorship of computer navigated DFLOWO. Hypotheses: We hypothesize that use of computer navigation will improve the survivorship of distal femoral osteotomy. Methods: Ethics committee approval was obtained for this study. Due consent was taken for the use of data from all the patients for this study. A retrospective analysis of prospectively collected data for patients with lateral compartment arthritis who underwent navigated lateral opening wedge distal femoral osteotomy from December 2006 to November 2012 was performed. Consecutive patients of lateral compartment knee arthrosis aged less than 55 years who failed to respond to conservative management were included in the study. Patients who had end stage arthritis with fixed flexion deformity of > 15 degrees, < 90 degrees of knee flexion or who did not consent for the procedure were excluded. Included patients were operated by one of the three senior surgeons attached to our research institute. The included patients were followed up with clinical and radiological evaluation at regular intervals (6 weeks / 6 months / 1 year / 5years). The final follow-up for the included patients was done using email questionnaire of the patient reported outcomes measures. Conversion to either UKA or TKA during the follow-up was the end point. Additionally, this information was verified from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) database Results: 19 DFLOWO with mean age of 46.6 ± 6.5 years formed the study cohort. The coronal alignment was corrected from a mean of 7.1º (2-11º) valgus to mean 2.1º (0.5º - 3º) varus. IKDC scores improved from mean of 39 pre-op to 53 at the mean long-term follow-up of 9.1 years. KOOS scores at the long-term follow-up were pain-71, symptoms-56, activities of daily living-82, sports and recreation-59, quality of life-43. Survivorship of DFLOWO was 78.9% at a follow-up of 9.1 years. Presence of ≥ grade 2 ICRS cartilage degeneration in the medial compartment of knee and >7⁰ pre-operative valgus deformity strongly correlated with conversion to TKA at the long-term follow-up (r - 0.66). Conclusion: Computer navigated DFLOWO has satisfactory clinical outcomes and 79% survivorship in long-term follow-up. Presence of more than ICRS ≥ grade 2 degenerative changes in the medial compartment of knee with > 7 degrees pre-operative valgus deformity negatively affects the survivorship of DFLOWO in the long-term follow-up.

Objectives: The published rates of dissatisfaction following total knee replacement (TKR) range between 11-18%, with residual symptoms and psychological distress being important features. The aims of this study were to identify the prevalence and causes of dissatisfaction in a cohort of private practice patients, and to describe a post-operative management program which may improve satisfaction with their replaced knee in these patients. Methods: A cohort of 375 patients with unilateral TKR was evaluated to identify patients who were dissatisfied with TKR. Dissatisfied and satisfied patients were matched in terms of age, gender, follow-up duration and BMI. Psychological evaluation was performed using the pain catastrophizing scale (PCS), Depression, Anxiety and Stress Scale (DASS) and the Multidimensional Health Locus of Control (MHLC) scale. The pre and post-operative Oxford knee scores (OKS) and range of motion (ROM), preoperative grade of osteoarthritis, and prevalence of comorbidities were also compared between groups. Patients indicating dissatisfaction with their TKR were then followed up by phone on a second occasion 12months later. Those that indicated enduring dissatisfaction were invited to participate in a chronic pain program utilising cognitive behavioural therapy, desensitisation and coping strategies. Patients referred to the program were screened by the therapists for inclusion and enrolled into a flexible course of therapy. Pre- and post- intervention questionnaires will be used to determine the effect of the program on satisfaction rates (5-point Likert scale) and psychological responses to pain. Results: The final cohort consisted of 301 patients (response rate 80%), with 24 patients (6.5%) dissatisfied with the result of TKR. Persistent pain was the most common reason for dissatisfaction (n=10). Dissatisfied patients reported a significantly (P = 0.03) higher mean PCS score (mean±SD, 11.3±10.3), compared to satisfied patients (5.4±6.3) and a significantly (P = 0.02) higher depression component of the DASS (3.5±3.3 vs 1.4±1.6). In addition, dissatisfied patients returned a significantly (P = 0.02) lower internal locus of control (16.6±8.2 vs 21.3±8.2). The dissatisfied group also exhibited a reduced improvement in the OKS and ROM, as well as a lower preoperative grade of osteoarthritis compared to satisfied patients. Preliminary analysis revealed that five patients (21%) became satisfied with their knee despite no intervention occurring between measurements. Of the remaining patients, five patients (21%) did not think their ongoing issues were severe enough to warrant further intervention, and nine patients (38%) were referred directly to the program. It is expected that these results will shed new light on the potential management options for these patients that identify as dissatisfied after a primary unilateral TKR. Conclusion: Dissatisfied patients exhibit higher scores for catastrophisation and depression, with lower self confidence in managing their knee symptoms. In addition, they have lesser improvements in the OKS and ROM. Thus, both physical as well as psychological factors contribute to dissatisfaction. Identification of these factors can help in planning focused interventions to address dissatisfaction. This is the longest follow-up of such a cohort; our results so far indicate that 21% of such patients can improve spontaneously with time which challenges some conventional beliefs. The results of the 38% of patients who remain dissatisfied and will undergo the program will determine whether such an intervention will be worthwhile in this difficult clinical situation.

Purpose The introduction of patient-specific instruments (PSI) for guiding bone cuts could increase the incidence of malalignment in primary total knee arthroplasty. The purpose of this study was to assess the agreement between one type of patient-specific instrumentation (Zimmer PSI) and the pre-operative plan with respect to bone cuts and component alignment during TKR using imageless computer navigation.MethodsA consecutive series of 30 femoral and tibial guides were assessed in-theatre by the same surgeon using computer navigation. Following surgical exposure, the PSI cutting guides were placed on the joint surface and alignment assessed using the navigation tracker. The difference between in-theatre data and the pre-operative plan was recorded and analysed.ResultsThe error between in-theatre measurements and pre-operative plan for the femoral and tibial components exceeded 3° for 3 and 17 % of the sample, respectively, while the error for total coronal alignment exceeded 3° for 27 % of the sample.ConclusionThe present results indicate that alignment with Zimmer PSI cutting blocks, assessed by imageless navigation, does not match the pre-operative plan in a proportion of cases. To prevent unnecessary increases in the incidence of malalignment in primary TKR, it is recommended that these devices should not be used without objective verification of alignment, either in real-time or with post-operative imaging. Further work is required to identify the source of discrepancies and validate these devices prior to routine use.Level of evidenceII.

This investigation evaluated the Smith and Nephew VISIONAIRE patient-specific cutting block (PSCB) system for total knee arthroplasty. A consecutive series of 60 patients were recruited. Intraoperative computer navigation was used to evaluate the accuracy of the cutting blocks in the coronal and sagittal planes for the tibia, as well as rotational plane for the femur. The PSCB would have placed 79.3% of the sample within +3° of neutral in the coronal plane, while the rotational and sagittal alignment results within +3° were 77.2% and 54.5% respectively. The VISIONAIRE PSCB system achieved unacceptable accuracy in the coronal plane and even less in the sagittal and rotational planes compared to computer navigation. Caution is recommended before PSCB are used routinely without objective verification of alignment.