Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are well-established operative interventions in the treatment of knee osteoarthritis (KOA). However, which of these interventions is more beneficial, to patients with KOA, is not known and remains a topic of much debate. Aims: (i) To determine whether UKA or HTO is more beneficial in the treatment of isolated medial compartment KOA, via an assessment of patient-reported outcome measures (PROMs). (ii) To investigate the relationship between PROMs and radiographic parameters of knee joint orientation/alignment. This longitudinal observational study assessed a total of 42 patients that had undergone UKA (n=23) or HTO (n=19) to treat isolated medial compartment KOA. The PROMs assessed, pre-operatively and 1-year post-operatively, consisted of the: self-administered comorbidity questionnaire; short form-12; oxford knee score; knee injury and osteoarthritis outcome score; and the EQ-5D-5L. The radiographic parameters of knee joint alignment/orientation assessed, pre-operatively and 8-weeks post-operatively, included the: hip-knee-ankle angle; mechanical axis deviation; and the angle of the Mikulicz line. Statistical analysis demonstrated an overall significant (p<0.001), pre-operative to post-operative, improvement in the PROM scores of both groups. There were no significant differences in the post-operative PROM scores of the UKA and HTO group. Correlation analyses revealed that pre-operatively, a more distolaterally angled Mikulicz line was associated with worse knee function (p<0.05) and overall health (p<0.05); a relationship that, until now, has not been investigated nor commented upon within the literature. UKAs and HTOs are both efficacious operations that provide a comparable degree of clinical benefit to patients with isolated medial compartment KOA. To further the scientific/medical community's understanding of the factors that impact upon health-outcomes in KOA, future research should seek to investigate the mechanism underlying the relationship, between Mikulicz line and PROMs, observed within the current study

Objectives. This study reports on a secondary exploratory analysis of the early clinical outcomes of a randomised clinical trial comparing robotic arm-assisted unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis of the knee with manual UKA performed using traditional surgical jigs. This follows reporting of the primary outcomes of implant accuracy and gait analysis that showed significant advantages in the robotic arm-assisted group. Methods. A total of 139 patients were recruited from a single centre. Patients were randomised to receive either a manual UKA implanted with the aid of traditional surgical jigs, or a UKA implanted with the aid of a tactile guided robotic arm-assisted system. Outcome measures included the American Knee Society Score (AKSS), Oxford Knee Score (OKS), Forgotten Joint Score, Hospital Anxiety Depression Scale, University of California at Los Angeles (UCLA) activity scale, Short Form-12, Pain Catastrophising Scale, somatic disease (Primary Care Evaluation of Mental Disorders Score), Pain visual analogue scale, analgesic use, patient satisfaction, complications relating to surgery, 90-day pain diaries and the requirement for revision surgery. Results. From the first post-operative day through to week 8 post-operatively, the median pain scores for the robotic arm-assisted group were 55.4% lower than those observed in the manual surgery group (p = 0.040). At three months post-operatively, the robotic arm-assisted group had better AKSS (robotic median 164, interquartile range (IQR) 131 to 178, manual median 143, IQR 132 to 166), although no difference was noted with the OKS. At one year post-operatively, the observed differences with the AKSS had narrowed from a median of 21 points to a median of seven points (p = 0.106) (robotic median 171, IQR 153 to 179; manual median 164, IQR 144 to 182). No difference was observed with the OKS, and almost half of each group reached the ceiling limit of the score (OKS > 43). A greater proportion of patients receiving robotic arm-assisted surgery improved their UCLA activity score. Binary logistic regression modelling for dichotomised outcome scores predicted the key factors associated with achieving excellent outcome on the AKSS: a pre-operative activity level > 5 on the UCLA activity score and use of robotic-arm surgery. For the same regression modelling, factors associated with a poor outcome were manual surgery and pre-operative depression. Conclusion. Robotic arm-assisted surgery results in improved early pain scores and early function scores in some patient-reported outcomes measures, but no difference was observed at one year post-operatively. Although improved results favoured the robotic arm-assisted group in active patients (i.e. UCLA ⩾ 5), these do not withstand adjustment for multiple comparisons. Cite this article: M. J. G. Blyth, I. Anthony, P. Rowe, M. S. Banger, A. MacLean, B. Jones. Robotic arm-assisted versus conventional unicompartmental knee arthroplasty: Exploratory secondary analysis of a randomised controlled trial. Bone Joint Res 2017;6:631–639. DOI: 10.1302/2046-3758.611.BJR-2017-0060.R1

Objective. Total Hip Arthroplasty (THA) and Total Knee Arthroplasty (TKA) bring relief of pain and functional disability to patients with end stage osteoarthritis, however the literature on their impact on patients’ level of physical activity (PA) is scarce. Methods. Cross-sectional study, performed in 2012, in 515 patients who underwent THA/TKA surgery in 2010–2011 and a random sample of persons aged >40 years from the Dutch general population participating in a national survey in the same period. PA in minutes per week (min/week) and adherence to the Dutch recommendation for health enhancing PA was measured by means of the Short QUestionnaire to ASsess Health enhancing PA (SQUASH) Additional assessments included socio-demographic characteristics, the presence of comorbidities, BMI and Short Form-12. Multivariable linear (total min/week) and logistic regression analyses (meeting PA recommendation), adjusting for confounders, were performed for THA and TKA separately. Results. 258 THA patients (64% female, mean age 70.0 (SD9.2)), 221 TKA patients (67% female, mean age 70.2 (SD8.9)) and 4373 persons from the general population sample (52% female, age 59.0 (SD12.0)) were included. In both regression analyses, the presence of joint arthroplasty was statistically significantly associated with more total min/week spent on PA (THA 7.0% increase, 95%-CI (2.0%–12.6%); TKA 7.4% increase, 95%-CI (1.6%–13.4%)) and a higher chance of adherence with PA recommendations (THA OR 1.90, 95%-CI (1.12–3.03); TKA OR 1.94, 95%-CI (1.19–3.15)). Conclusion. 6-18 months after surgery, THA/TKA patients were more physically active than a random sample of persons >40 years from the Dutch general population

Background. Over 96% of primary total hip replacements (THR) recorded in the National Joint Registry (NJR) are performed through a posterior or lateral surgical approach. There is no high quality evidence available to support the use of one approach over the other in primary THR and even less evidence when the outcome of revision THR is considered. Methods. Questionnaires were sent to 267 patients who had revision hip replacements between January 2006 and March 2010 for aseptic loosening. They rated their pain from 0–10, and used the Self-Administered Patient Satisfaction Scale (SAPS), Oxford Hip Score (OHS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Short form-12 (SF-12). Results. We performed 275 revision total hip replacements for aseptic loosening on patients in whom the primary operation details were available. Their mean age was 69 years (SD12) with 43% male and 57% right-sided procedures. 205 patients responded to our questionnaires (209/275 hips, 76%). Unfortunately 19 patients had died, 4 had dementia and 13 declined to participate. We were unable to contact a further 33.Grouping by approach, 20% (43/209) had primary and revision lateral approaches, 20% (43/209) had primary lateral and revision posterior and 60% (123/209) had both primary and revision via posterior approaches. The WOMAC and OHS were significantly better in patients who had a posterior approach for both primary and revision surgery, compared to those that did not (OHS p=0.028, WOMAC p=0.026). We found no significant differences in pain, satisfaction or health-related quality of life between the groups. Conclusions. Registry data may help further explore the relationship between surgical approach and outcome in revision hip surgery. A randomised controlled trial of the posterior versus lateral approach for revision surgery would provide a definitive answer. Level of Evidence. 2b - retrospective cohort study. Disclosures. No financial disclosures or conflicts of interests from any authors