Background and purposeRecurrent dislocation is the commonest cause of early revision of a total hip arthropasty (THA). We examined the effect of femoral head size and surgical approach on revision rate for dislocation, and for other reasons, after total hip arthroplasty (THA).Patients and methodsWe analyzed data on 166,231 primary THAs and 3,754 subsequent revision THAs performed between 2007 and 2015, registered in the Dutch Arthroplasty Register (LROI). Revision rate for dislocation, and for all other causes, were calculated by competing-risk analysis at 6-year follow-up. Multivariable Cox proportional hazard regression ratios (HRs) were used for comparisons.ResultsPosterolateral approach was associated with higher dislocation revision risk (HR =1) than straight lateral, anterolateral, and anterior approaches (HR =0.5–0.6). However, the risk of revision for all other reasons (especially stem loosening) was higher with anterior and anterolateral approaches (HR =1.2) and lowest with posterolateral approach (HR =1). For all approaches, 32-mm heads reduced the risk of revision for dislocation compared to 22- to 28-mm heads (HR =1 and 1.6, respectively), while the risk of revision for other causes remained unchanged. 36-mm heads increasingly reduced the risk of revision for dislocation but only with the posterolateral approach (HR =0.6), while the risk of revision for other reasons was unchanged. With the anterior approach, 36-mm heads increased the risk of revision for other reasons (HR =1.5).InterpretationCompared to the posterolateral approach, direct anterior and anterolateral approaches reduce the risk of revision for dislocation, but at the cost of more stem revisions and other revisions. For all approaches, there is benefit in using 32-mm heads instead of 22- to 28-mm heads. For the posterolateral approach, 36-mm heads can safely further reduce the risk of revision for dislocation.

Metal-on-metal hip arthroplasty is associated with elevated levels of cobalt and chromium ions. The effects of cobalt and chromium ions on cell number, activity, expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) and oxidative stress on human osteoblast-like cells were addressed. Saos-2 cells were supplemented with Co 2þ , Cr 3þ , or Co 2þ þ Cr 3þ (1:2) at 0, 1, 10, and 100 mg/L and incubated for 24, 48, 72, and 96 h. Cell activity was assessed by MTT-assay and cell number by Crystal Violet staining. RNA levels of OPG and RANKL were evaluated using real-time quantitative polymerase chain reaction (qPCR). Compared to controls Co 2þ reduced cell numbers: at 10 mg/L by 17 AE 8% after 48 h and at 100 mg/L after 24 h by 35 AE 8%. Cr 3þ decreased cell numbers at 10 mg/L after 48 and 72 h. Co 2þ þ Cr 3þ combined at 1 mg/L lowered cell numbers after 24 and 96 h (17 AE 13, resp. 13 AE 4%). The 10 and 100 mg/L concentrations reduced cell numbers significantly after 24, 48, and 96 h. Cr 3þ reduced osteoblast activity at 1, 10, and 100 mg/L at all incubation times. The strongest reduction (11 AE 1%) was seen at 100 mg/L after 96 h. The OPG/RANKL ratio was reduced after 72 h with almost all Co 2þ and Cr 3þ concentrations. After 96 h, glutathione, superoxide dismutase, and catalase levels were indicative for an oxidative stress response in all samples. In conclusion, cobalt and chromium ions reduce human osteoblast activity, reduce OPG/RANKL ratio and lead to oxidative stress. Keywords: metal-on metal; osteoblasts; oxidative stress; OPG; RANKL Total hip arthroplasty (THA) is a well-accepted therapy for hip osteoarthritis, with long lasting good clinical results. Survival rates of most THA's are documented at more than 95% over 10-15 years. Wear, osteolysis, and loosening have emerged as the dominant concerns among orthopedic hip surgeons. Polyethylene wear particles trigger a foreign body granulomatous reaction, inflammation, and immune reactions leading to the secretion of various bone resorbing agents (cytokines, prostaglandins). This results in peri-prosthetic bone loss, contributing to loosening and failure of the prosthesis.1 One of the key factors in peri-prosthetic osteolysis is receptor activator of nuclear factor kappaB ligand (RANKL) and strong correlations have been found between its expression and the amount of polyethylene wear debris and the degree of osteolysis. 3 also related the presence of polyethylene to RANKL expression. In general, osteoclastogenesis is largely regulated by receptor activator of nuclear factor kappaB (RANK), RANKL, and osteoprotegerin (OPG). RANKL stimulates differentiation of osteoclast precursor cells into mature osteoclasts and is required for osteoclast activity; in fact, RANKLtreated mice show increased bone resorbtion. On the other hand, OPG decreases the number of osteoclasts and mice treated with OPG exhibit lowered osteoclast activity and increased bone volume. 4 In order to avoid polyethylene wear-related loosening and t...

Background Recent technological developments such as wearable sensors and tablets with a mobile internet connection hold promise for providing electronic health home-based programs with remote coaching for patients following total hip arthroplasty. It can be hypothesized that such a home-based rehabilitation program can offer an effective alternative to usual care. Objective The aim of this study was to determine the effectiveness of a home-based rehabilitation program driven by a tablet app and remote coaching for patients following total hip arthroplasty. Methods Existing data of two studies were combined, in which patients of a single-arm intervention study were matched with historical controls of an observational study. Patients aged 18-65 years who had undergone total hip arthroplasty as a treatment for primary or secondary osteoarthritis were included. The intervention consisted of a 12-week home-based rehabilitation program with video instructions on a tablet and remote coaching (intervention group). Patients were asked to do strengthening and walking exercises at least 5 days a week. Data of the intervention group were compared with those of patients who received usual care (control group). Effectiveness was measured at four moments (preoperatively, and 4 weeks, 12 weeks, and 6 months postoperatively) by means of functional tests (Timed Up & Go test and the Five Times Sit-to Stand Test) and self-reported questionnaires (Hip disability and Osteoarthritis Outcome Score [HOOS] and Short Form 36 [SF-36]). Each patient of the intervention group was matched with two patients of the control group. Patient characteristics were summarized with descriptive statistics. The 1:2 matching situation was analyzed with a conditional logistic regression. Effect sizes were calculated by Cohen d. Results Overall, 15 patients of the intervention group were included in this study, and 15 and 12 subjects from the control group were matched to the intervention group, respectively. The intervention group performed functional tests significantly faster at 12 weeks and 6 months postoperatively. The intervention group also scored significantly higher on the subscales “function in sport and recreational activities” and “hip-related quality of life” of HOOS, and on the subscale “physical role limitations” of SF-36 at 12 weeks and 6 months postoperatively. Large effect sizes were found on functional tests at 12 weeks and at 6 months (Cohen d=0.5-1.2), endorsed by effect sizes on the self-reported outcomes. Conclusions Our results clearly demonstrate larger effects in the intervention group compared to the historical controls. These results imply that a home-based rehabilitation program delivered by means of internet technology after total hip arthroplasty can be more effective than usual care. Trial Registration ClinicalTrials.gov NCT03846063; https://clinicaltrials.gov/ct2/show/NCT03846063 and German Registry of Clinical Trials DRKS00011345; https://tinyurl.com/yd32gmdo

No abstract

No abstract

Background Rifampin is generally advised in the treatment of acute staphylococcal periprosthetic joint infections (PJI). However, if, when, and how to use rifampinremains a matter of debate. We evaluated the outcome of patients treated with and without rifampin, and analyzed the influence of timing, dose and co-antibiotic. Methods Acute staphylococcal PJIs treated with surgical debridement between 1999 and 2017, and a minimal follow-up of 1 year were evaluated. Treatment failure was defined as the need for any further surgical procedure related to infection, PJI-related death or the need for suppressive antimicrobial treatment. Results A total of 669 patients were analyzed. Treatment failure was 32.2% (131/407) in patients treated with rifampin and 54.2% (142/262) in whom rifampin was withheld (P < 0.001). The most prominent effect of rifampin was observed in knees (treatment failure 28.6% versus 63.9%, respectively, P < 0.001). The use of rifampin was an independent predictor of treatment success in the multi-variate analysis (OR 0.30, 95% CI 0.20 – 0.45). In the rifampin group, the use of a co-antibiotic other than a fluoroquinolone or clindamycin (OR 10.1, 95% CI 5.65 – 18.2) and the start of rifampin within 5 days after surgical debridement (OR 1.96, 95% CI 1.08 – 3.65) were predictors of treatment failure. The dosing of rifampin had no effect on outcome. Conclusions Our data supports the use of rifampin in acute staphylococcal PJIs treated with surgical debridement, particularly in knees. Immediate start of rifampin after surgical debridement should probably be discouraged, but requires further investigation.

ObjectivesA key predictor for developing chronic residual pain after total knee or hip arthroplasty (TKA/THA) is sensitisation. Sensitisation can be defined as an ‘increased responsiveness of nociceptive neurons in the nervous system’. Aim of this study is to investigate the effects of preoperative treatment with duloxetine in sensitised knee and hip osteoarthritis (OA) patients on postoperative chronic residual pain up to 1 year after arthroplasty.SettingA multicentre, pragmatic, prospective, randomised clinical trial was conducted in three secondary care hospitals in the Netherlands.ParticipantsPatients with primary knee/hip OA who were planned for TKA/THA were screened using the modified painDETECT Questionnaire. Patients whose painDETECT score indicated that sensitisation may be present were eligible for participation. 111 participants were included and randomly assigned 1:1 to an intervention or control group. The intervention group received additional duloxetine treatment, the control group did not receive any additional treatment but was allowed to continue with any pain medication they were already taking.InterventionsPreoperative oral treatment for 7 weeks with 60 mg/day of duloxetine was compared with usual care.Primary and secondary outcome measuresPrimary outcome measure was pain at 6 months after arthroplasty, assessed with the Pain Subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS) or the Hip disability and Osteoarthritis Outcome Score (HOOS) with a 0–100 scale. Secondary outcome measures were Visual Analogue Scale (VAS), and neuropathic-like pain measured using the modified PainDETECT Questionnaire. Longitudinal data collection included time points directly after duloxetine treatment, 1-day preoperatively, and 6 weeks, 6 months and 12 months postoperatively.ResultsMean improvement in the KOOS/HOOS pain subscale at 6 months postoperatively was 37 (SD 28.1) in the intervention group and 43 (SD 26.5) in the control group. No statistically significant difference was found in change score 6 months postoperatively between the two groups (p=0.280). 12 patients from the intervention group (21%) discontinued duloxetine due to adverse effects.ConclusionsPreoperative targeted treatment with duloxetine in end-stage knee and hip OA patients with sensitisation does not influence postoperative chronic residual pain after TKA/THA.Trial registration numberNTR4744.

Background Success of debridement, antibiotics and implant retention (DAIR) in early periprosthetic joint infection (PJI) largely depends on the presence of a mature biofilm. At what time point DAIR should be disrecommended is unknown. This multicenter study evaluated the outcome of DAIR in relation to time after index arthroplasty. Methods We retrospectively evaluated PJIs occurring within 90 days after surgery and treated with DAIR. Patients with bacteremia, arthroscopic debridements and a follow-up <1 year were excluded. Treatment failure was defined as 1) any further surgical procedure related to infection 2) PJI-related death, 3) long-term suppressive antibiotics. Results 769 patients were included. Treatment failure occurred in 294 patients (38%) and was similar between time-intervals from index arthroplasty to DAIR: week 1-2: 42% (95/226); week 3-4: 38% (143/378); week 5-6: 29% (29/100), week 7-12: 42% (27/65). Exchange of modular components was performed to a lesser extent in the early compared with the late post-surgical course (41% vs 63%, p<0.001). The causative microorganisms, comorbidities and duration of symptoms were comparable between time-intervals. Conclusions DAIR is a viable option in patients with early PJI presenting more than four weeks after index surgery as long as DAIR is performed at least within one week after the onset of symptoms and modular components can be exchanged.