Aims. Periprosthetic hip-joint infection is a multifaceted and highly detrimental outcome for patients and clinicians. The incidence of prosthetic joint infection reported within two years of primary hip arthroplasty ranges from 0.8% to 2.1%. Costs of treatment are over five-times greater in people with periprosthetic hip joint infection than in those with no infection. Currently, there are no national evidence-based guidelines for treatment and management of this condition to guide clinical practice or to inform clinical study design. The aim of this study is to develop guidelines based on evidence from the six-year INFection and ORthopaedic Management (INFORM) research programme. Methods. We used a consensus process consisting of an evidence review to generate items for the guidelines and online consensus questionnaire and virtual face-to-face consensus meeting to draft the guidelines. Results. The consensus panel comprised 21 clinical experts in orthopaedics, primary care, rehabilitation, and healthcare commissioning. The final output from the consensus process was a 14-item guideline. The guidelines make recommendations regarding increased vigilance and monitoring of those at increased risk of infection; diagnosis including strategies to ensure the early recognition of prosthetic infection and referral to
Introduction. As orthopaedics shifts towards value-based models of care, methods of evaluating the value of procedures such as a total hip arthroplasty (THA) will become crucial. Patient reported outcome measures (PROMs) can offer a meaningful way for patient-centered input to factor into the determination of value. Despite their benefits, PROMs can be difficult to interpret as statistically significant, but not clinically relevant, differences between groups can be found. One method of correcting this issue is by using a minimal clinically important improvement (MCII), defined as the smallest improvement in a PROM determined to be important to patients. This study aims to find demographic and surgical factors that are independently predictive of failing to achieve a MCII in pain and physical function at 1-year following THA. Methods. A total of 976 patients were enrolled into a prospective international, multicenter study evaluating the long-term clinical performance of two acetabular shells and two polyethylene liners from a single manufacturer. All patients consented to be followed with plain radiographs and a set of PROMs preoperatively and at 1-year after surgery. The outcomes considered in this study were achieving literature-defined MCIIs in pain and physical function at one year after THA. The MCII in pain was defined as achieving a 2-point decrease on the Numerical Rating Scale (NRS)-Pain or reporting a 1-year NRS-Pain value of 0, indicating no pain. The MCII in physical function was defined as achieving an 8.29-point increase on the SF-36 Physical Function subscore. Univariate analyses were conducted to determine if there were statistically significant differences between patients who did achieve and did not achieve a MCII. Variables tested included: demographic and surgical factors, general and mental health state, and preoperative radiographic findings such as deformity and joint space width (JSW). Significant variables were entered into a multivariable binary logistic regression. Receiver-operating characteristic (ROC) analysis was used to generate cutoff values for significant continuous variables. Youden's index was used to identify cutoff points that maximized both specificity and sensitivity. Results. Of 976 enrolled patients, 630 (65%) patients had complete preoperative and 1-year PROMs and a valid preoperative radiograph. Of the final cohort, 59 (9%) patients did not achieve the MCII in pain and 208 (33%) patients did not achieve the MCII in physical function following THA. Multivariable analysis determined that higher preoperative JSW (odds ratio (OR)=2.04; p<0.001), and lower preoperative SF-36 Mental Composite Score (MCS) (OR=0.96; p<0.001) were independently predictive of not achieving a MCII in pain. ROC analysis determined that cutoff points for preoperative JSW and MCS were 0.65mm and 47.4 points, respectively. In a separate multivariable regression, we found higher preoperative JSW (OR=1.40; p=0.010) and higher preoperative HHS (OR=1.03; p<0.001) to be independently predictive of not achieving a MCII in physical function. Cutoff points for preoperative JSW and HHS were respectively 0.65mm and 50.5 points. Conclusion. In the upcoming era of value-based
