Measurement properties of the HOOS-PS in revision total hip arthroplasty: a validation study on validity, interpretability, and responsiveness in 136 revision hip arthroplasty patients.

BACKGROUND AND PURPOSE: To determine whether the Hip disability and Osteoarthritis Outcome Score-Physical function Short-form (HOOS-PS) is able to appropriately evaluate physical function in revision hip arthroplasty patients, this study assesses psychometric properties of the Dutch HOOS-PS in this patient population. PATIENTS AND METHODS: We assessed psychometric properties of the HOOS-PS following the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) criteria. Content validity, including comprehensibility, comprehensiveness, and relevance of the items, was assessed using cognitive debriefing interviews in hip revision patients (n = 8) and orthopedic surgeons specialized in revision surgery (n = 7). Construct validity, responsiveness, and interpretability (floor/ceiling effects) were assessed in revision hip arthroplasty patients (baseline n = 136, follow-up n = 67). We formulated hypotheses a priori to assess construct validity and responsiveness using the EuroQol 5-Dimensions Health Questionnaire, Numeric Rating scale for pain, and Oxford Hip Score as comparators. All questionnaires were measured at baseline and 1 year postoperatively. RESULTS: We found insufficient content validity of the HOOS-PS, as relevance and comprehensibility of the items scored < 85% on the COSMIN criteria for revision hip arthroplasty patients. Construct validity was sufficient as all hypotheses were confirmed (≥ 75% COSMIN criteria). Interpretability was sufficient (< 15% COSMIN criteria) and responsiveness was insufficient (< 75% COSMIN criteria). INTERPRETATION: The Dutch HOOS-PS is not able to sufficiently evaluate physical function in revision hip arthroplasty patients. Minor changes in the items are needed for the HOOS-PS to become sufficiently content valid, because the HOOS-PS lacks relevant items and comprehensiveness.

A modified Gritti-Stokes amputation technique as a solution for recurring aseptic loosening of a knee arthroplasty: A single-patient case study.

CASE DESCRIPTION: A 56-year-old man with persistent knee pain and poor physical functioning due to recurring loosening of a (revised) total knee arthroplasty, was treated with a modified Gritti-Stokes amputation. OBJECTIVES: to describe the modified Gritti-Stokes amputation technique as an ultimate therapy for failed total knee arthroplasty and to assess the functional outcome for one patient 1 year post-surgery. STUDY DESIGN: a single patient case study. TREATMENT: a modified Gritti-Stokes amputation, with removal of the overlying cartilage and subchondral surfaces of both the patella and femur after removing the total knee arthroplasty. OUTCOMES: After rehabilitation, the patient has a fully end-bearing residual limb, is able to walk without pain (with a prosthesis) and perform his daily activities. CONCLUSIONS: In cases of recurring loosening of a (revised) total knee arthroplasty, a modified Gritti-Stokes amputation can create an end-bearing residual limb without pain and with good functional outcome.

First results of a uniform regional treatment protocol and registration for acute prosthetic join infection in the South-East of the Netherlands.

Introduction: Prosthetic joint infection (PJI) is a relatively uncommon (average incidence 0.5-2%) but devastating complication, with significant morbidity and leading to tremendously increased health care costs. In 2013, delegates from nine hospitals covering a large region in the South-East Netherlands composed one combined treatment protocol for acute PJI of total hip and knee arthroplasty (THA and TKA). This protocol was based on the definition of acute PJI according to Workgroup of the American Musculoskeletal Infection Society (MSIS) and the principles of debridement, antibiotics, irrigation and retention (DAIR). Methods: Patients with a THA or TKA treated with DAIR because of suspicion of PJI were selected from the online PJI database. PJI was defined as at least two phenotypically identical pathogens, isolated in cultures from at least two separate tissues, obtained from the affected prosthetic joint. Acute PJIs, occurring within 90 days after primary implantation, between January 2014 and December 2016, were analyzed. We analyzed the PJI incidence rate, patient clinical and microbiological characteristics of PJI, outcome of the DAIR treatment and adherence to the regional protocol. Results: A total of 310 primary THA or TKA with a suspected PJI were registered in the regional PJI database, 236 met the definition of acute PJI, representing overall incidence of 1.12%. Following the regional treatment protocol replacement of exchangeable parts took place in 45% in 2014 to 70% in 2016. After 12 months follow-up, prosthesis retention was achieved in 87% and 3% of the patients died within one year after the primary surgery. Conclusion: Results of the regional cohort are in line with the available literature. Regional collaboration and regular feedback on registered data resulted in better adherence to the combined treatment protocol. Despite our attempts to improve PJI care, PJI remains a serious complication of THA and TKA with a significant mortality rate and burden for the patient.

Optimization of the empirical antibiotic choice during the treatment of acute prosthetic joint infections: a retrospective analysis of 91 patients.

Background and purpose - The preferred treatment of an acute prosthetic joint infection (PJI) is debridement, antibiotics, irrigation and retention of the prosthesis (DAIR). The antibiotic treatment consists of an empirical and targeted phase. In the empirical phase, intravenous antibiotics are started after surgery before micro-organisms are determined in microbiological cultures. Which empirical antibiotic is used differs between hospitals, partly reflecting geographic differences in susceptibility spectrums. We investigated whether flucloxacillin should remain the antibiotic of choice in our hospital for empiric treatment of acute PJI with DAIR. Patients and methods - We retrospectively analyzed 91 patients treated for PJI with DAIR between 2012 and 2016. The susceptibility of micro-organisms was determined in multiple cultures of periprosthetic tissue and synovial fluid for 3 antibiotics: amoxicillin/clavulanic acid, cefazolin, and flucloxacillin. Results - Positive microbiological cultures from 68 patients were analyzed. Staphylococcus aureus was the predominant pathogen, cultured in half of the patients. In one-third of patients more than 1 micro-organism was found. On a patient level, the data showed that 65% were responsive to flucloxacillin, 76% to amoxicillin/clavulanic acid, and 79% to cefazolin. Interpretation - Flucloxacillin appeared to be a suboptimal choice in our patient population treated with DAIR. We therefore changed our practice to cefazolin as the preferred antibiotic in the empirical treatment of acute PJI with DAIR.

The long-term prognosis of Legg-Calvé-Perthes disease: a historical prospective study with a median follow-up of forty one years.

PURPOSE: The purpose of this study is predicting the clinical and radiological long-term outcome and identifying prognostic factors of Legg-Calvé-Perthes disease (LCPD) in Catterall 2 and 3 hips. METHODS: Sixty hips (59 patients) were diagnosed with LCPD between 1959 to 1974 and were followed prospectively. Forty-two of these 60 hips were classified as Catterall 2 or 3. In 2002, 33 hips (32 patients) with Catterall type 2 or 3 were evaluated clinically and radiographically. In 2010, 27 hips (26 patients) were re-evaluated. RESULTS: In 2002, 15 hips had Catterall 2 type LCPD and 18 hips Catterall 3. Twelve of the 33 hips (36%) had signs of osteoarthritis. In 2010, 14 hips were classified as Catterall 2 and 13 hips as Catterall 3. Catterall 2 hips had a significantly better Harris Hip Score (HHS) (p = 0.001). There were 15 hips (55%) with signs of osteoarthritis. CONCLUSION: The long-term prognosis of LCPD Catterall type 2 and 3 is relatively benign. However, more than 50% of the patients will develop signs of osteoarthritis between the 4th and 5th decades. At the latest follow-up a strong increase in the number of cases with osteoarthritis was seen. Sphericity of the femoral head is an important predicting factor in the development of osteoarthritis.

Reason for revision TKA predicts clinical outcome: prospective evaluation of 150 consecutive patients with 2-years followup.

BACKGROUND: There is limited knowledge regarding the relationship between the reason for revising a TKA and the clinical outcome in terms of satisfaction, pain, and function with time. QUESTIONS/PURPOSES: In a cohort of patients receiving a fully revised TKA, we hypothesized (1) outcomes would differ according to reason for revision at 2 years, (2) outcomes would improve gradually during those 2 years, (3) rates of complications differ depending on the reason for revision, and (4) patients with complications have lower scores. METHODS: We studied a prospective cohort of 150 patients receiving a fully revised TKA using a single implant system in two high-volume centers at 24 months of followup. VAS satisfaction, VAS pain, The Knee Society Scoring System(©) (KSS) clinical and functional scores, and complication rate were correlated with their reasons for revision, including septic loosening, aseptic loosening, component malposition, instability, and stiffness. RESULTS: The aseptic loosening group showed better outcomes compared with the instability, malposition, and septic loosening groups, which showed intermediate results (p < 0.05). The stiffness group performed significantly worse on all outcome measures. The outcome for patients with a complication, after treatment of the complication, was less favorable. CONCLUSIONS: The reason for revision TKA predicts clinical outcomes. Satisfaction, pain reduction, and functional improvement are better and complication rates are lower after revision TKA for aseptic loosening than for other causes of failure. For component malposition, instability, and septic loosening groups, there may be more pain and a higher complication rate. For stiffness, the outcomes are less favorable in all scores. LEVEL OF EVIDENCE: Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.