The June 2015 Hip & Pelvis Roundup³⁶⁰ looks at: neuraxial anaesthesia and large joint arthroplasty; revision total hip arthoplasty: factors associated with re-revision surgery; acetabular version and clinical outcomes in impingement surgery; hip precautions may be ineffective; implant selection and cost effectiveness; femoroacetabular impingement in the older age group; multiple revision in hip arthroplasty

The August 2014 Hip & Pelvis Roundup³⁶⁰ looks at: Serial MRIs best for pseudotumour surveillance; Is ultrasound good enough for MOM follow-up?; Does weight loss in obese patients help?; Measuring acetabular anteversion on plain films; Two-stage one-stage too many in fungal hip revisions? and 35 is the magic number in arthroplasty.

We retrospectively reviewed 30 two-stage revision procedures in 28 patients performed for fungal peri-prosthetic joint infection (PJI) after a primary total knee replacement. Patients were followed for at least two years or until the infection recurred. The mean follow-up for patients who remained free of infection was 4.3 years (2.3 to 6.1). Overall, 17 patients were assessed as American Society of Anesthesiologists grade 3 or 4. The surgical protocol included removal of the infected implant, vigorous debridement and insertion of an articulating cement spacer. This was followed by at least six weeks of antimicrobial treatment and delayed reimplantation in all patients. The mean interval between removal of the prosthesis and reimplantation was 9.5 weeks (6 to 24). After reimplantation, patients took antifungal agents orally for a maximum of six months. Two knees became reinfected at one and two months post-operatively, respectively: one of these subsequently required arthrodesis because of uncontrolled infection.

Fungal PJIs can be treated successfully by removal of all infected material, appropriate antimicrobial treatment and delayed reimplantation.

Prophylactic antibiotics can decrease the risk of wound infection and have been routinely employed in orthopaedic surgery for decades. Despite their widespread use, questions still surround the selection of antibiotics for prophylaxis, timing and duration of administration. The health economic costs associated with wound infections are significant, and the judicious but appropriate use of antibiotics can reduce this risk.

This review examines the evidence behind commonly debated topics in antibiotic prophylaxis and highlights the uses and advantages of some commonly used antibiotics.

Cite this article: Bone Joint J 2016;98-B:1014–19.

Peri-prosthetic infection remains a leading cause of revision surgery. Recent publications from the American Musculoskeletal Infection Society have sought to establish a definition of peri-prosthetic infection based on clinical findings and laboratory investigations. The limitations of their approach are discussed and an alternative definition is proposed, which it is felt may better reflect the uncertainties encountered in clinical practice.

The purpose of this study was to compare the diagnostic accuracy for the detection of infection between the culture of fluid obtained by sonication (SFC) and the culture of peri-implant tissues (PITC) in patients with early and delayed implant failure, and those with unsuspected and suspected septic failure. It was hypothesised that SFC increases the diagnostic accuracy for infection in delayed, but not early, implant failure, and in unsuspected septic failure. The diagnostic accuracy for infection of all consecutive implants (hardware or prostheses) that were removed for failure was compared between SFC and PITC. This prospective study included 317 patients with a mean age of 62.7 years (9 to 97). The sensitivity for detection of infection using SFC was higher than using PITC in an overall comparison (89.9% versus 67%, respectively; p < 0.001), in unsuspected septic failure (100% versus 48.5%, respectively; p < 0.001), and in delayed implant failure (88% versus 58%, respectively; p < 0.001). PITC sensitivity dropped significantly in unsuspected compared with suspected septic failure (p = 0.007), and in delayed compared with early failure (p = 0.013). There were no differences in specificity.

Sonication is mainly recommended when there is implant failure with no clear signs of infection and in patients with delayed implant failure. In early failure, SFC is not superior to PITC for the diagnosis of infection and, therefore, is not recommended as a routine diagnostic test in these patients.

Cite this article: Bone Joint J 2013;95-B:244–9.

Adverse reaction to wear and corrosion debris is a cause for concern in total hip arthroplasty (THA). Modular junctions are a potential source of such wear products and are associated with secondary pseudotumour formation.

We present a consecutive series of 17 patients treated at our unit for this complication following metal-on-highly cross-linked polyethylene (MoP) THA. We emphasise the risk of misdiagnosis as infection, and present the aggregate laboratory results and pathological findings in this series.

The clinical presentation was pain, swelling or instability. Solid, cystic and mixed soft-tissue lesions were noted on imaging and confirmed intra-operatively. Corrosion at the head–neck junction was noted in all cases. No bacteria were isolated on multiple pre- and intra-operative samples yet the mean erythrocyte sedimentation rate was 49 (9 to 100) and C-reactive protein 32 (0.6 to 106) and stromal polymorphonuclear cell counts were noted in nine cases.

Adverse soft–tissue reactions can occur in MoP THA owing to corrosion products released from the head–neck junction. The diagnosis should be carefully considered when investigating pain after THA. This may avoid the misdiagnosis of periprosthetic infection with an unidentified organism and mitigate the unnecessary management of these cases with complete single- or two-stage exchange.

Cite this article: Bone Joint J 2015;97-B:1024–1030.

The December 2014 Knee Roundup³⁶⁰ looks at: national guidance on arthroplasty thromboprophylaxis is effective; unicompartmental knee replacement has the edge in terms of short-term complications; stiff knees, timing and manipulation; neuropathic pain and total knee replacement; synovial fluid α-defensin and CRP: a new gold standard in joint infection diagnosis?; how to assess anterior knee pain?; where is the evidence? Five new implants under the spotlight; and a fresh look at ACL reconstruction

Objectives

The objective of this study was to compare the elution characteristics, antimicrobial activity and mechanical properties of antibiotic-loaded bone cement (ALBC) loaded with powdered antibiotic, powdered antibiotic with inert filler (xylitol), or liquid antibiotic, particularly focusing on vancomycin and amphotericin B.

The April 2014 Hip & Pelvis Roundup³⁶⁰ looks at: Recent arthroplasty and flight; whether that squeak could be a fracture; diagnosing early infected hip replacement; impaction grafting at a decade; whether squeaking is more common than previously thought; femoral offset associated with post THR outcomes; and periprosthetic fracture stabilisation.

The rate of peri-prosthetic infection following total joint replacement continues to rise, and attempts to curb this trend have included the use of antibiotic-loaded bone cement at the time of primary surgery. We have investigated the clinical- and cost-effectiveness of the use of antibiotic-loaded cement for primary total knee replacement (TKR) by comparing the rate of infection in 3048 TKRs performed without loaded cement over a three-year period versus the incidence of infection after 4830 TKRs performed with tobramycin-loaded cement over a later period of time of a similar duration. In order to adjust for confounding factors, the rate of infection in 3347 and 4702 uncemented total hip replacements (THR) performed during the same time periods, respectively, was also examined. There were no significant differences in the characteristics of the patients in the different cohorts.

The absolute rate of infection increased when antibiotic-loaded cement was used in TKR. However, this rate of increase was less than the rate of increase in infection following uncemented THR during the same period. If the rise in the rate of infection observed in THR were extrapolated to the TKR cohort, 18 additional cases of infection would have been expected to occur in the cohort receiving antibiotic-loaded cement, compared with the number observed. Depending on the type of antibiotic-loaded cement that is used, its cost in all primary TKRs ranges between USD $2112.72 and USD $112 606.67 per case of infection that is prevented.

Cite this article: Bone Joint J 2014;96-B:65–9.