Effectiveness of two-stage revision with commercial polymethylmethacrylate articulated hip spacer: similar outcomes against monomicrobial and polymicrobial hip periprosthetic joint infections

Abstract. Background: orthopaedic surgeons still struggle against a devastating complication – periprosthetic joint infection (PJI). A two-stage revision is considered the gold standard for chronic PJI for several authors, with success rates over 90 %. This strategy implies the remotion of the prosthesis and the implantation of an antibiotic-impregnated cement spacer in the joint. The primary objective of this study was to assess the effectiveness of a two-stage revision approach using a commercial prefabricated antibiotic-impregnated cement hip spacer for the treatment of hip PJI regarding monomicrobial and polymicrobial infections. Secondly, to assess risk factors for failure of two-stage revision. Material and methods: we conducted a retrospective study on patients that underwent revision of total hip arthroplasty (THA) between January 2002 and January 20218. We included adult patients with a diagnosis of chronic hip PJI that underwent two-stage revision using a prefabricated gentamicin-impregnated cement of polymethylmethacrylate (PMMA) hip spacer. We assessed whether it was monomicrobial or polymicrobial infections and comorbidities. Treatment success was defined when eradication of the infection was observed and no further procedures or mortality were registered after the second stage. Persistence or recurrence of infection was considered a failure of treatment. Results: the final series consisted of 84 patients treated with the same hip spacer: 60 (71.4 %) monomicrobial and 24 (28.6 %) polymicrobial joint infections with an overall follow-up of 59.0 (36.0–84.0) months. The overall success rate was 90.5 %. Eight (9.5 %) patients failed. Smoking and BMI greater than 30 m kg−2 were identified independent risk factors for failure in multivariate analysis. Conclusion: our study suggests that prefabricated gentamicin-impregnated PMMA spacer is an effective tool for the treatment of PJI, achieving similar outcomes whether it is monomicrobial or polymicrobial infections. Randomized prospective studies are needed to obtain more reliable conclusions.

Infectious disease specialists and teamwork strategies worldwide: the World Association against Infection in Orthopedics and Trauma (WAIOT) and SICOT continue to cooperate in fighting musculoskeletal infections

Bone and joint infections are associated with a devastating global burden. The successful treatment of these infections requires a multidisciplinary approach between orthopedic surgeons and experts of different disciplines. This multidisciplinary approach has gained ground over the past decades in modern infection units as a more effective treatment strategy, yielding better outcomes regarding infection eradication rates, length of hospital stay, and overall cost of treatments. Additionally, preventing and managing musculoskeletal infections requires strong connections between medical associations, biological laboratories, and the pharmaceutical industry worldwide. In this context, SICOT and World Association against Infection in Orthopaedics and Trauma (WAIOT) relationships have been increasing. The present editorial article discusses the multidisciplinary approach for managing bone and joint infections worldwide, explores the controversies in practices in terms of training, area of expertise, and extent of clinical involvement, and emphasizes the role of societies in research, prevention and management of musculoskeletal infections. The purpose is to acknowledge what orthopedics can obtain from specialists dealing with bone and joint infections and to consolidate their practice to provide the best care for orthopedic patients.

Metal Hypersensitivity or Missed Periprosthetic Joint Infection? A Critical Review

The World Association Against Infection in Orthopedics And Trauma (W.A.I.O.T.) Study Group on Bone And Joint Infection Definitions Metal hypersensitivity (MHS) has been investigated by several authors as a possible reason for painful total joint arthroplasty, with controversial results. Periprosthetic joint infection (PJI) is another possible source of unexplained pain and implant failure that may be difficult to diagnose if not properly investigated. We performed this critical review to assess whether the current literature on MHS includes an adequate diagnostic workup to discern metal allergy from PJI. The results of this review highlight the importance of assessing patients for PJI before making a diagnosis of MHS and emphasize that the methods currently used to exclude PJI are substantially inadequate. Therefore, well-designed clinical trials with adequate diagnostic protocols and definitions of PJI that can differentiate MHS from low-grade PJI are needed. [Orthopedics. 2022;45(2):e73-e78.].

The effectiveness of antibiotic cement-coated nails in post-traumatic femoral and tibial osteomyelitis - comparative analysis of custom-made versus commercially available nails

Background: The first objective of this retrospective study was to assess infection control rates in patients with chronic post-traumatic osteomyelitis (CPTO) of the femur or tibia treated with antibiotic cement-coated nails. The second objective was to compare the efficacy of custom-made nails versus commercially available antibiotic-coated nails in terms of infection control and need for reoperation. Methods: We reviewed a consecutive series of CPTO patients treated with antibiotic-coated nails who had a minimum follow-up of 24 months. We recorded the characteristics of the initial injury, the type of nail used, cement–nail debonding, infecting microorganisms, operating time, infection control, need for reoperation, and failure rate. We performed a comparative analysis between nails manufactured in the operating room (i.e., custom-made) and those commercially available. Results: Thirty patients were included. The affected bones were the femur (n=15) and the tibia (n=15). Twenty-one of the 30 initial injuries were open fractures. Staphylococcus aureus was the most frequently isolated microorganism (50 %). Sixteen patients were treated with custom-made nails and 14 with commercially available antibiotic-coated nails. At the time of extraction, four out of five custom-made antibiotic-coated nails experienced cement–bone debonding. Commercial nails were associated with shorter operating times (p<0.0001). The overall infection control rate was 96.66 %. Eight (26.66 %) patients needed reoperation. There was one failure (3.33 %) in the group treated with custom-made antibiotic-coated nails. We did not find significant differences between nail types in terms of reoperation, infection control, and failure rate. Conclusions: The use of antibiotic cement-coated nails proved useful in CPTO treatment. Commercially available nails had significantly shorter operating times and did not present cement–bone debonding during removal. Our results seem to indicate that both nail types are similar in terms of infection control and reoperation rates.

Structural Allograft and Induced Membrane Technique for Treatment of 10-cm Segmental Femoral Bone Defect: A Case Report

CASE

A modified induced membrane technique for the treatment of a posttraumatic 10-cm infected segmental femoral defect is reported. The first stage involved debridement and insertion of an antibiotic cement spacer and 2 Ender nails. Reconstruction was performed with a 14-cm structural bone allograft, inverted and telescoped into both ends of the remaining host femur, and stabilized with an interlocking nail. Progressive weight-bearing was allowed at 3 weeks with full weight-bearing achieved at 6 months.

CONCLUSION

The use of a telescoped structural allograft and intramedullary nailing as the second stage of the Masquelet induced membrane technique facilitated postoperative rehabilitation, increased surface contact between host and graft bone, and improved integration.

Congenital Fibular Deficiency: Total Knee Arthroplasty with Extraarticular Deformity: A Case Report

CASE

A total knee arthroplasty (TKA) was performed on a 35-year-old man with congenital fibular deficiency and a 20° varus and 28° antecurvatum tibial deformity of the left lower limb.

CONCLUSION

One-stage TKA and correction of the extraarticular deformity by means of intraarticular bone resections and a standard soft tissue release were performed to restore the limb's mechanical axis. Patients with congenital fibular deficiency present a wide range of limb deformities because of bone deficiencies or treatment sequels, which might require a specific surgical technique and small-sized implants to obtain good results during a TKA.

Extended trochanteric osteotomy (ETO) and fluted tapered modular stems in revision hip arthroplasty. Does ETO integrity or consolidation, really matter?

Introduction

The objective of this study was to assess if the fracture and/or non-union of extended trochanteric osteotomy (ETO) affected the behavior and survival of modular fluted and tapered distal fixation stems in revision total hip arthroplasties (rTHA).

Methods

We retrospectively analyzed 52 rTHA in 52 patients. Preoperative diagnoses were mechanical loosening (42 cases), septic loosening (8), periprosthetic fracture (1), and femoral stem fracture (1). According to the Paprosky classification, femoral bone stock deficiencies were 19 type-II, 26 type IIIA, and 7 type IIIB. We assessed the behavior of the osteotomy (union, fracture, migration) and the survival and behavior (integration and subsidence) of prosthetic femoral stems.

Results

ETO union and non-union rates were 84.61% (44 patients) and 15.38% (8 cases) respectively. There were twelve (23%) intra-operative fractures of the osteotomy fragment and 11 (21.15%) migrations (4.5 mm on average). We observed bone union in 39 (75%) stems and 13 (25%) stable fibrous unions. Nine (17.3%) stems subsided 7 mm (2-15 mm) on average before becoming stable. Stem subsidence and integration was not significantly affected by ETO fracture/no fracture or union/non-union. The postoperative Harris Hip Score (HHS) improved significantly as compared to the pre-operative HHS (38.41 ± 3.54 vs 85.29 ± 3.36; p < 0.01). Patients were followed up for 55 (24-100) months. The overall implant survival at the end of follow-up was 100%.

Conclusions

In this series, neither the non-union nor the intra-operative fracture of the ETO segment affected the behavior or medium-term survival of femoral stems.

Distal fixation stems for revision of total hip replacement

The purpose of this study was to retrospectively assess patients treated with modular, non-cemented, tapered, fluted, distal fixation stems. We included patients with 24 months mínimum follow-up. Diagnosis that led to revisions were described. The radiographic analysis was made with preoperative, immediate postoperative and last control postoperative X-rays. Sixty-seven patients met inclusion criteria. We observed 59,7% (n=40) Osteointegration, 34,3% of Stable Fibrosis and 5,97% Unstable fibrosis. Stress Shielding was registered with 10,44% and Subsidence was observed in 34,3% of the patients. Modular, fluted, tapered, distal fixation stems have an excellent survival rates.

The World Association against Infection in Orthopaedics and Trauma (WAIOT) procedures for Microbiological Sampling and Processing for Periprosthetic Joint Infections (PJIs) and other Implant-Related Infections

While implant-related infections continue to play a relevant role in failure of implantable biomaterials in orthopaedic and trauma there is a lack of standardised microbiological procedures to identify the pathogen(s). The microbiological diagnosis of implant-related infections is challenging due to the following factors: the presence of bacterial biofilm(s), often associated with slow-growing microorganisms, low bacterial loads, previous antibiotic treatments and, possible intra-operative contamination. Therefore, diagnosis requires a specific set of procedures. Based on the Guidelines of the Italian Association of the Clinical Microbiologists (AMCLI), the World Association against Infection in Orthopaedics and Trauma has drafted the present document. This document includes guidance on the basic principles for sampling and processing for implant-related infections based on the most relevant literature. These procedures outline the main microbiological approaches, including sampling and processing methodologies for diagnostic assessment and confirmation of implant-related infections. Biofilm dislodgement techniques, incubation time and the role of molecular approaches are addressed in specific sections. The aim of this paper is to ensure a standardised approach to the main microbiological methods for implant-related infections, as well as to promote multidisciplinary collaboration between clinicians and microbiologists.