The efficacy and safety of patient-specific instrumentation in primary total knee replacement: a systematic review and meta-analysis.

INTRODUCTION: Patient-specific instrumentation (PSI) for primary total knee arthroplasty (TKA) surgery has been shown to increase accuracy of component positioning. However, it is unclear whether this also translates to actual benefits for patients in terms of better outcomes (efficacy) or less complications such as revisions (safety). We therefore systematically reviewed the literature to determine the efficacy and safety of PSI in primary TKA. METHODS: Randomized controlled trials comparing PSI to non-PSI in primary TKA were included. A random effects model was used with meta-regression in case of heterogeneity. RESULTS: Forty-three studies were included with a total of 1816 TKA in the PSI group and 1887 TKA in the control group. There were no clinically relevant differences between the PSI-group and non-PSI group regarding all outcomes. There was considerable heterogeneity: meta-regression analyses showed that the year the study was published was an important effect modifier. Early publications tended to show a positive effect for PSI compared to non-PSI TKA, whereas later studies found the opposite. CONCLUSION: Based on evidence of moderate certainty, our study suggested that there were no clinically relevant differences in efficacy and safety between patients treated with PSI TKA and patients treated with non-PSI TKA.

Effectiveness of mechanical cleaning, antibiotics, and induction heating on eradication of Staphylococcus aureus in mature biofilms.

AIMS: Here we used a mature seven-day biofilm model of Staphylococcus aureus, exposed to antibiotics up to an additional seven days, to establish the effectiveness of either mechanical cleaning or antibiotics or non-contact induction heating, and which combinations could eradicate S. aureus in mature biofilms. METHODS: Mature biofilms of S. aureus (ATCC 29213) were grown on titanium alloy (Ti6Al4V) coupons for seven days and were subjected to the following treatments or their combinations: antibiotics, mechanical cleaning, or heat shock by induction heating of 60°C for one minute. Experiments were repeated at least five times. RESULTS: In the untreated biofilm, growth up to 1.8×1011 colony-forming units (CFU)/cm2 was observed. Treatment with ciprofloxacin, flucloxacillin, vancomycin, cefuroxime, and amoxicillin all with rifampicin gave 6.0 log, 6.1 log, 1.4 log, 4.8 log, and 3.6 log reduction in CFU/cm2, respectively. Mechanical cleaning alone resulted in 4.9 log reduction and induction heating in 7.3 log reduction. There was an additional effect of ciprofloxacin, flucloxacillin, and induction heating when used in combinations. There was no additional effect for mechanical cleaning. No bacterial growth could be detected after induction heating followed by seven days of ciprofloxacin with rifampicin. CONCLUSION: Mechanical cleaning, antibiotics, and non-contact induction heating reduced the bacterial load of mature S. aureus biofilms with approximately 5 log or more as a single treatment. The effect of mechanical cleaning on mature S. aureus biofilms was limited when used in combination with antibiotics and/or induction heating.Cite this article: Bone Joint Res 2022;11(9):629-638.

Non-contact induction heating and SAAP-148 eliminate persisters within MRSA biofilms mimicking a metal implant infection.

Implant-associated infections are the primary cause of complications following orthopaedic surgery. Due to biofilm and persister formation, current treatments, i.e. surgical debridement followed by antibiotics, often fail. There is an urgent need for alternative strategies to combat such infections. Therefore, the present study investigated the effects of non-contact induction heating (NCIH), the antimicrobial peptide SAAP-148 and combinations thereof on bacterial counts in 7 d mature biofilms and in persister-enriched biofilms of methicillin-resistant Staphylococcus aureus (MRSA) on titanium-aluminium-niobium (TAN) discs. Enrichment of persisters was achieved by daily exposure of mature biofilms to high doses of rifampicin and ciprofloxacin for 3 consecutive days. To heat up the TAN discs, a miniaturised induction heater was built and successfully validated. Using this apparatus, NCIH resulting in surface temperatures up to 85 °C eradicated all the bacteria in immature biofilms but not in mature biofilms, whereas persisters were already eliminated at surface temperatures ≥ 70 °C. SAAP-148 at concentrations > 25.6 µmol/L reduced the persister counts in antibiotics-exposed, mature biofilms. As surface temperatures > 60 °C can have detrimental effects on the surrounding tissues, the maximum temperature of NCIH used in combination with SAAP-148 on persisters was set to 60 °C. Results revealed that this combination was slightly more effective than the peptide or NCIH alone in eliminating biofilm-embedded persisters. NCIH and SAAP-148 can be applied both invasively and non-invasively in various treatment scenarios. Together, combinations of NCIH and SAAP-148 might be a promising treatment strategy to combat metal-implant-associated infections.

Outcome of Debridement, Antibiotics, and Implant Retention for Staphylococcal Hip and Knee Prosthetic Joint Infections, Focused on Rifampicin Use: A Systematic Review and Meta-Analysis.

The treatment of staphylococcal prosthetic joint infection (PJI) with debridement, antibiotics, and retention of the implant (DAIR) often results in failure. An important evidence gap concerns the treatment with rifampicin for PJI. A systematic review and meta-analysis were conducted to assess the outcome of staphylococcal hip and/or knee PJI after DAIR, focused on the role of rifampicin. Studies published until September 2, 2020 were included. Success rates were stratified for type of joint and type of micro-organism. Sixty-four studies were included. The pooled risk ratio for rifampicin effectiveness was 1.10 (95% confidence interval, 1.00-1.22). The pooled success rate was 69% for Staphylococcus aureus hip PJI, 54% for S aureus knee PJI, 83% for coagulase-negative staphylococci (CNS) hip PJI, and 73% for CNS knee PJI. Success rates for MRSA PJI (58%) were similar to MSSA PJI (60%). The meta-analysis indicates that rifampicin may only prevent a small fraction of all treatment failures.

Debridement, Antibiotics, and Implant Retention with the Direct Anterior Approach for Acute Periprosthetic Joint Infection Following Primary THA.

BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication following total hip replacement. The direct anterior approach for total hip replacement is becoming increasingly popular. However, little is known about the success rate of treatment with debridement, antibiotics, and implant retention (DAIR) using the direct anterior approach. The aim of this study was to analyze the effectiveness of DAIR using this approach and identify patient and surgical factors that influence the results. METHODS: Seventy-four patients (75 hips) in whom DAIR had been performed were identified from the records of the weekly multidisciplinary infection meeting and the laboratory information management systems. In 4% (3 hips), modular components were exchanged. To consider competing risks (death), we used competing risk models. RESULTS: The competing risk analysis showed a successful outcome after DAIR of 82% at 4 years of follow-up; this rate was 89% at 4 years follow-up when excluding patients managed with gentamicin beads. The sensitivity analysis revealed that obesity (body mass index [BMI] of ≥30 kg/m2), use of gentamicin beads, and an erythrocyte sedimentation rate (ESR) of >40 mm/hr increased the risk of failure. CONCLUSIONS: DAIR using the direct anterior approach without the routine exchange of modular components offers a success rate that is comparable with other approaches for eradicating acute PJI following primary hip arthroplasty. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Segmental induction heating of orthopaedic metal implants.

OBJECTIVES: Prosthetic joint infection (PJI) is a devastating complication following total joint arthroplasty. Non-contact induction heating of metal implants is a new and emerging treatment for PJI. However, there may be concerns for potential tissue necrosis. It is thought that segmental induction heating can be used to control the thermal dose and to limit collateral thermal injury to the bone and surrounding tissues. The purpose of this study was to determine the thermal dose, for commonly used metal implants in orthopaedic surgery, at various distances from the heating centre (HC). METHODS: Commonly used metal orthopaedic implants (hip stem, intramedullary nail, and locking compression plate (LCP)) were heated segmentally using an induction heater. The thermal dose was expressed in cumulative equivalent minutes at 43°C (CEM43) and measured with a thermal camera at several different distances from the HC. A value of 16 CEM43 was used as the threshold for thermal damage in bone. RESULTS: Despite high thermal doses at the HC (7161 CEM43 to 66 640 CEM43), the thermal dose at various distances from the HC was lower than 16 CEM43 for the hip stem and nail. For the fracture plate without corresponding metal screws, doses higher than 16 CEM43 were measured up to 5 mm from the HC. CONCLUSION: Segmental induction heating concentrates the thermal dose at the targeted metal implant areas and minimizes collateral thermal injury by using the non-heated metal as a heat sink. Implant type and geometry are important factors to consider, as they influence dissipation of heat and associated collateral thermal injury.Cite this article: B. G. Pijls, I. M. J. G. Sanders, E. J. Kuijper, R. G. H. H. Nelissen. Segmental induction heating of orthopaedic metal implants. Bone Joint Res 2018;7:609-619. DOI: 10.1302/2046-3758.711.BJR-2018-0080.R1.

[Increased mortality in metal-on-metal versus non-metal-on-metal primary total hip arthroplasty at 10 years and longer follow-up: a systematic review and meta-analysis]. / Verhoogde mortaliteit bij patiënten met een metaal-op-metaal heupprothese.

OBJECTIVE: To determine the mortality and the morbidity in patients with metal-on-metal articulations (MOM THA) when compared to patients with non-metal-on-metal articulations (non-MOM THA) after primary total hip arthroplasty. DESIGN: Systematic review, meta-analyses and meta-regression (registration: PROSPERO 2014:CRD42014007417). METHOD: Search of PubMed, MEDLINE, EMBASE, Web of Science, Cochrane, CINAHL, AcademicSearchPremier, ScienceDirect, Wiley and clinical trial registers. We included randomised controlled trials and observational studies of primary total hip arthroplasty comparing MOM THA with non-MOM THA. We used meta-regression to identify and evaluate potential modifying variables such as follow-up duration. RESULTS: Forty-seven studies were included, comprising over 4,000 THA in randomised trials and over 500,000 THA in observational studies. For mortality, random effects analysis revealed a higher pooled risk difference (RD) of 0.7% (95%-CI: 0.0-2.3%; I-square 42%); the heterogeneity was explained by differences in follow-up. When restricted to studies with long term follow-up (i.e. 10 years or more), the RD for mortality was 8,5% (95%-CI: 5,8-11,2). Further subgroup analyses and meta-regression random effects models revealed no evidence for other modifying variables (study level covariates, e.g. resurfacing vs. non-resurfacing MOM) than follow-up duration. CONCLUSION: Meta-analysis suggests there may be an increased long-term risk of mortality associated with MOM THA compared to patients with non-MOM THA.

Non-contact electromagnetic induction heating for eradicating bacteria and yeasts on biomaterials and possible relevance to orthopaedic implant infections: In vitro findings.

OBJECTIVES: Infection of implants is a major problem in elective and trauma surgery. Heating is an effective way to reduce the bacterial load in food preparation, and studies on hyperthermia treatment for cancer have shown that it is possible to heat metal objects with pulsed electromagnetic fields selectively (PEMF), also known as induction heating. We therefore set out to answer the following research question: is non-contact induction heating of metallic implants effective in reducing bacterial load in vitro? METHODS: Titanium alloy cylinders (Ti6Al4V) were exposed to PEMF from an induction heater with maximum 2000 watts at 27 kHz after being contaminated with five different types of micro-organisms: Staphylococcus epidermidis; Staphylococcus aureus; Pseudomonas aeruginosa; spore-forming Bacillus cereus; and yeast Candida albicans. The cylinders were exposed to incremental target temperatures (35°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C) for up to 3.5 minutes. RESULTS: There was an average linear heating rate of 0.39°C per second up to the target temperature, and thereafter the target temperature was maintained until the end of the experiment. At 60°C and higher (duration 3.5 minutes), there was a 6-log reduction or higher for every micro-organism tested. At 60°C, we found that the shortest duration of effective induction heating was 1.5 minutes. This resulted in a 5-log reduction or higher for every micro-organism tested. CONCLUSION: Non-contact induction heating of a titanium disk is effective in reducing bacterial load in vitro. These promising results can be further explored as a new treatment modality for infections of metal orthopaedic implants.Cite this article: B. G. Pijls, I. M. J. G. Sanders, E. J. Kuijper, R. G. H. H. Nelissen. Non-contact electromagnetic induction heating for eradicating bacteria and yeasts on biomaterials and possible relevance to orthopaedic implant infections: In vitro findings. Bone Joint Res 2017;6:323-330. DOI: 10.1302/2046-3758.65.BJR-2016-0308.R1.

Increased Mortality in Metal-on-Metal versus Non-Metal-on-Metal Primary Total Hip Arthroplasty at 10 Years and Longer Follow-Up: A Systematic Review and Meta-Analysis.

IMPORTANCE: There are concerns about increased mortality in patients with metal-on-metal bearings in total hip arthroplasty (THA). OBJECTIVE: To determine the mortality and the morbidity in patients with metal-on-metal articulations (MOM THA) compared to patients with non-metal-on-metal articulations (non-MOM THA) after primary total hip arthroplasty. DATA SOURCES: Search of PubMed, MEDLINE, EMBASE, Web of Science, Cochrane, CINAHL, AcademicSearchPremier, ScienceDirect, Wiley and clinical trial registers through March 2015, augmented by a hand search of references from the included articles. No language restrictions were applied. STUDY SELECTION: Two reviewers screened and identified randomised controlled trials and observational studies of primary total hip arthroplasty comparing MOM THA with non-MOM THA. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently extracted study data and assessed risk of bias. Risk differences (RD) were calculated with random effect models. Meta-regression was used to explore modifying factors. MAIN OUTCOMES AND MEASURES: Difference in mortality and difference in morbidity expressed as revisions and medical complications between patients with MOM THA and non-MOM THA. RESULTS: Forty-seven studies were included, comprising 4,000 THA in randomised trials and over 500,000 THA in observational studies. For mortality, random effects analysis revealed a higher pooled RD of 0.7%, 95%, confidence interval (CI) [0.0%, 2.3%], I-square 42%; the heterogeneity was explained by differences in follow-up. When restricted to studies with long term follow-up (i.e. 10 years or more), the RD for mortality was 8.5%, 95%, CI [5.8%, 11.2%]; number needed to treat was 12. Further subgroup analyses and meta-regression random effects models revealed no evidence for other moderator variables (study level covariates, e.g. resurfacing vs. non-resurfacing MOM) than follow-up duration. The quality of the evidence presented in this meta-analysis was characterized as moderate according to the CLEAR-NPT (for non-pharmacological trials) and Cochrane risk of bias Table. CONCLUSIONS AND RELEVANCE: Meta-analysis suggests there may be an increased long-term risk of mortality and revision surgery for patients with MOM THA compared to patients with non-MOM THA. REGISTRATION: PROSPERO 2014:CRD42014007417.

The natural history of the rheumatoid shoulder: a prospective long-term follow-up study.

The purpose of this study was to evaluate the natural history of rheumatoid disease of the shoulder over an eight-year period. Our hypothesis was that progression of the disease is associated with a decrease in function with time. A total of 22 patients (44 shoulders; 17 women, 5 men, (mean age 63)) with rheumatoid arthritis were followed for eight years. All shoulders were assessed using the Constant score, anteroposterior radiographs (Larsen score, Upward-Migration-Index (UMI)) and ultrasound (US). At final follow-up, the Short Form-36, disabilities of the arm, shoulder and hand (DASH) Score, erythrocyte sedimentation rate and use of anti-rheumatic medication were determined. The mean Constant score was 72 points (50 to 88) at baseline and 69 points (25 to 100) at final follow-up. Radiological evaluation showed progressive destruction of the peri-articular structures with time. This progression of joint and rotator cuff destruction was significantly associated with the Constant score. However, at baseline only the extent of rotator cuff disease and the UMI could predict the Constant score at final follow-up. A plain anteroposterior radiograph of the shoulder is sufficient to assess any progression of rheumatoid disease and to predict functional outcome in the long term by using the UMI as an indicator of rotator cuff degeneration.

Treatment of supination deformity for obstetric brachial plexus injury: a systematic review and meta-analysis.

PURPOSE: To conduct a systematic review and meta-analysis of the literature evaluating treatment outcome for supination deformity in obstetric brachial plexus injury. METHODS: We included studies on brachial plexus and supination deformity with follow-up of at least one year and quantitative measurements of forearm mean passive pronation and position at rest. Meta-analysis was used to explore modifying factors. RESULTS: An elaborate search strategy resulted in 366 studies, of which 13 were included totaling 238 patients (157 osteotomies and 71 biceps rerouting). There was a 75° gain in position at rest and a 65° gain in passive pronation for the osteotomy group, compared to a 79° gain in position at rest for the biceps rerouting group. More severe deformities had greater gains. No influence of age was found. Important adverse effects were hardware failure and a biceps rupture. Recurrence in the osteotomy group was 20% to 40%, versus none in the soft-tissue group. CONCLUSIONS: This review showed an overall benefit for forearm osteotomies and for biceps rerouting for supination deformity with the gain proportionate to the severity of the deformity. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

A systematic review and meta-regression of mobile-bearing versus fixed-bearing total knee replacement in 41 studies.

Mobile-bearing (MB) total knee replacement (TKR) was introduced to reduce the risk of aseptic loosening and wear of polyethylene inserts. However, no consistent clinical advantages of mobile- over fixed-bearing (FB) TKR have been found. In this study we evaluated whether mobile bearings have an advantage over fixed bearings with regard to revision rates and clinical outcome scores. Furthermore, we determined which modifying variables affected the outcome. A systematic search of the literature was conducted to collect clinical trials comparing MB and FB in primary TKR. The primary outcomes were revision rates for any reason, aseptic loosening and wear. Secondary outcomes included range of movement, Knee Society score (KSS), Oxford knee score (OKS), Short-Form 12 (SF-12) score and radiological parameters. Meta-regression techniques were used to explore factors modifying the observed effect. Our search yielded 1827 publications, of which 41 studies met our inclusion criteria, comprising over 6000 TKRs. Meta-analyses showed no clinically relevant differences in terms of revision rates, clinical outcome scores or patient-reported outcome measures between MB and FB TKRs. It appears that theoretical assumptions of superiority of MB over FB TKR are not borne out in clinical practice.

Differences in long-term fixation between mobile-bearing and fixed-bearing knee prostheses at ten to 12 years' follow-up: a single-blinded randomised controlled radiostereometric trial.

This single-blinded randomised controlled trial investigated whether one design of mobile-bearing (MB) total knee replacement (TKR) has any advantage over a fixed-bearing (FB) design on long-term fixation as measured by radiostereometry. The amount of wear underneath the mobile bearing was also evaluated. A series of 42 knees was randomised to MB or FB tibial components with appropriate polyethylene inserts and followed for between ten and 12 years, or until the death of the patient. The polyethylene in the MB group was superior in that it was gamma-irradiated in inert gas and was calcium-stearate free; the polyethylene in the FB group was gamma-irradiated in air and contained calcium stearate. In theory this should be advantageous to the wear rate of the MB group. At final follow-up the overall mean migration was 0.75 mm (SD 0.76) in the MB group and 0.66 mm (SD 0.4) in the FB group, with the FB group demonstrating more posterior tilt and the MB group more internal rotation. In the FB group there was one revision for aseptic loosening, but none in the MB group. There were no significant differences in clinical or radiological scores. For the MB group, the mean linear wear rate on the under-surface was 0.026 mm/year (SD 0.014). This was significantly smaller than the wear rate of 0.11 mm/year (SD 0.06) in the MB between femur and polyethylene (p < 0.001). Nevertheless, even in a best-case setting the mobile bearings of this TKR design had no apparent advantage in terms of fixation over the FB knee prosthesis at ten to 12 years. The wear underneath the mobile bearing was small and is unlikely to be clinically relevant.

Revision surgery is overestimated in hip replacement.

OBJECTIVES: The Kaplan-Meier estimation is widely used in orthopedics to calculate the probability of revision surgery. Using data from a long-term follow-up study, we aimed to assess the amount of bias introduced by the Kaplan-Meier estimator in a competing risk setting. METHODS: We describe both the Kaplan-Meier estimator and the competing risk model, and explain why the competing risk model is a more appropriate approach to estimate the probability of revision surgery when patients die in a hip revision surgery cohort. In our study, a total of 62 acetabular revisions were performed. After a mean of 25 years, no patients were lost to follow-up, 13 patients had undergone revision surgery and 33 patients died of causes unrelated to their hip. RESULTS: The Kaplan-Meier estimator overestimates the probability of revision surgery in our example by 3%, 11%, 28%, 32% and 60% at five, ten, 15, 20 and 25 years, respectively. As the cumulative incidence of the competing event increases over time, as does the amount of bias. CONCLUSIONS: Ignoring competing risks leads to biased estimations of the probability of revision surgery. In order to guide choosing the appropriate statistical analysis in future clinical studies, we propose a flowchart.

Reliability study of the sonographic measurement of the acromiohumeral distance in symptomatic patients.

BACKGROUND: The purpose of this study was to evaluate the inter- and intra-observer reliability and accuracy of sonographic (US) acromiohumeral distance (AHD) measurement for both experienced and novice operators in US in patients suffering from subacromial impingement syndrome. METHOD: A total of 43 patients (50 shoulders) diagnosed with subacromial impingement syndrome were recruited from an orthopedic outpatient clinic. The US measurement of AHD was obtained consecutively in a neutral position and in a 60 degrees abduction position. A total of 300 blinded measurements were taken. RESULT: In the neutral abduction group the intra- observer interclass correlation coefficient (ICC) was 0.94 for the experienced operator and 0.92 for the novice operator. The inter-observer ICC was 0.70 and the accuracy was 1.1 mm. In the 60 degrees abduction group, the intra-observer ICC was 0.90 for the experienced operator and 0.87 for the novice operator. The inter-observer ICC was 0.64 and the accuracy was 1.4 mm. All ICCs were significant at a level of p < 0.0001. CONCLUSION: The inaccuracy of the method was 1 mm regardless of the experience of the observer. US AHD measurement in patients with shoulder complaints is not as accurate as reported in healthy subjects. This may have important implications for the clinical use of this parameter.