Implant Material As A Modifiable Risk Factor For Infection In THA: A Literature And Registry Review

Aim: Periprosthetic Joint Infection (PJI) is a rare but serious post-operative complication of hip replacement that often ends in complex implant revision and dramatically impacts the quality of life of the patient. Finally, costs associated with PJI significantly impact healthcare systems. Current research focuses on understanding the mechanisms of infection and identifying the risk factors related thereto. The objective of this study was to examine the potential impact of bearing materials on the incidence of infection in THA. Methods: Registries are a valuable tool to analyze large cohorts of THA patients and the influence of selected parameters on the clinical outcome of the surgeries. Data from THA patients recorded in the NJR, AOA and NZ registries were analyzed with respect to the incidence of infection. Material data and scientific publications were also reviewed to investigate if the incidence of PJI might be correlated with the specific bearing material used. Results: The use of metal bearings was consensually identified in all large patient cohorts as an independent risk factor for PJI. In contrast, using ceramic bearings was associated with a lower risk of revision for PJI.1 In vitro and ex vivo studies comparing the biological response to ceramic, metal and polyethylene materials are helpful to explain these findings. Metal exposure might activate the immune system and the released metal particles and ions might trigger adverse reactions with high inflammatory potential In contrast, extreme low wear ceramic bearings are well tolerated, show an excellent biological behavior 2,3,4,5,6 and might even support the wound healing process by initiating a healthy fibrotic pseudo-capsulation4. Furthermore, low wear is less likely to serve as a nidus for infection. Discussion and conclusion: Considering modifiable risk factors prior to THA is a key aspect for surgery success, implant longevity and patient satisfaction. Selecting a bearing material with enhanced biocompatibility like ceramics seems to have a measureable impact on the clinical outcomes. Favourable host-implant interactions might explain this observation. Literature: 1) Lenguerrand et al. Risk factors associated with revision for prosthetic joint infection after hip replacement: a prospective observational cohort study The Lancet, 2018DOI: https://doi.org/10.1016/S1473-3099(18)30345-1 2) Faye PA et al. Biomed Mater. 2017;12(1):015023 3) Cunningham BW et al. Journal of Neurosurgery: Spine. 2013;19(3):336-350 4) Savarino L et al. Acta Orthopaedica. 2009;80(2):162-167 5) Asif IM et al. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf. FBIOE.2016.01.00793 6) Asif I M et al. Characterisation and Biological Impact of Wear Particles from Composite Ceramic Hip Replacements. PhD thesis, University of Leeds (2018). http://etheses.whiterose.ac.uk/20563/ 7) Pitto et al Are ceramic-on-ceramic bearings in total hip arthroplasty associated with reduced revision risk for late dislocation? Clin Orthop Relat Res. 2015;473(12):3790–3795. doi:10.1007/s11999-015-4395-6

Outcome of revision surgery in recurrent dislocation of primary total hip arthroplasty

Background: The cause of recurrent dislocation following primary total hip arthroplasty (THA) is multifactorial. A re-dislocation rate of up-to 34% following revision is reported. The aim of this study was to determine the re-dislocation rates following revision for recurrent THR dislocation. Methodology: Patients who underwent revision for recurrent dislocation between January 2008 and January 2015 were identified. We identified the date and type of primary implant, overall number and reasons for dislocation, revision implant details and complication data. Results: Over an 8-year period, 24 patients underwent revision. The median age was 77 (68–85) years, median time to first dislocation was 78 (23–160) months and median number of dislocations was 3 (2–4) with a mean follow-up of 18 months. Socket Mal-Orientation (10) and Abductor deficiency (5) were the main causes of recurrent dislocation. 21 patients (88%) underwent revision of both components, 1 patient underwent isolated cup revision and 2 patients had revision of acetabular component with insertion of a BioBall. There were no dislocations within 90 days of revision surgery. 4 patients had late dislocations (3 recurrent, 1 isolated). There was no significant increase risk of dislocation after revision surgery in the neck of femur group ( p = 0.467). Conclusions: We report favourable outcomes for revision of both components for recurrent dislocation with no dislocations within 90 days. The overall late dislocation rate was 16.7%, however, these patients have settled following closed reduction. Due to its multifactorial aetiology, both component revision can be considered in this patient population.

Surgical repair for abductor lesion after revision total hip arthroplasty: a systematic review

Background: Abductor mechanism lesions represent a severe complication after revision total hip arthroplasty (rTHA). The resulting abductor insufficiency can cause limping, pain, instability, and a higher rate of failure, thus requiring further revision surgery. In case of severe degeneration and retraction of the abductor mechanism, several different surgical treatments are needed. Aim: To systematically review all studies reporting on surgical treatment of severe abductor lesion after rTHA, focusing on surgical techniques, and clinical and functional results. Method: Scientific databases were accessed in December 2018 to identify studies addressing the surgical management of severe abductor disruption after rTHA. The PRISMA guidelines were followed. Data were extracted from the identified articles and summarised. Only data about patients with symptoms of abductor insufficiency after rTHA were included in the database. Results: 9 retrospective studies were included, all being retrospective case series reporting on a total of 92 patients. Several surgical strategies have been described and performed: a repair using a synthetic mesh was reported in 1 study; 2 studies reported on local muscle transfer (gluteus maximus transfer or advancement); vastus lateralis advancement was described in 4 studies while in 2 studies the injury was repaired with the use of an allograft. Overall positive results have been reported in terms of pain reduction, while poor to mild functional scores with persistent limping have often been observed in the postoperative period. Conclusions: The short follow-up time of the reviewed studies is inadequate to uncover any late dislocation, implant failure or different complications related to abductor mechanism reconstruction.

Outcome of a hemispherical porous-coated acetabular component with a proximally hydroxyapatite-coated anatomical femoral component

Aims We previously reported the long-term results of the cementless Duraloc-Profile total hip arthroplasty (THA) system in a 12- to 15-year follow-up study. In this paper, we provide an update on the clinical and radiological results of a previously reported cohort of patients at 23 to 26 years´ follow-up. Patients and Methods Of the 99 original patients (111 hips), 73 patients (82 hips) with a mean age of 56.8 years (21 to 70) were available for clinical and radiological study at a minimum follow-up of 23 years. There were 40 female patients (44 hips) and 33 male patients (38 hips). Results All acetabular and femoral components were well fixed and showed signs of bone ingrowth. Nine acetabular components were revised due to wear-osteolysis-related problems and four due to late dislocation. The probability of not having component revision at 25 years was 83.2% (95% confidence interval (CI) 74.5 to 91.8; number at risk 41). Acetabular osteolysis was observed in ten hips. The mean femoral head penetration was 1.52 mm (sd 0.8) at 15 years and 1.92 mm (sd 1.2) at 25 years. Receiver operating characteristic (ROC) analysis revealed that mean femoral penetration with a value of 0.11 mm/year or more was associated with the appearance of osteolysis. The 25-year Kaplan–Meier survival with different endpoints was 89.9% for acetabular osteolysis (95% CI 83.3 to 96.5), 92.1% for proximal femoral osteolysis (95% CI 86.1 to 98.2), and 75.5% for femoral osteopenia (95% CI 66.5 to 84.5). Conclusion The Duraloc-Profile THA system showed excellent long-term bone fixation. Nevertheless, monitoring is recommended in order to detect wear and late dislocations in this population that was relatively young at the time of surgery. Cite this article: Bone Joint J 2019;101-B:378–385.

Trans-iris fixation of dislocated in-the-bag intraocular lenses

Purpose: The aim of this article is to describe the safety and efficacy of trans-iris suture fixation for the management of late dislocation of in-the-capsular-bag intraocular lenses following uncomplicated cataract surgery. Patients and methods: Eleven eyes of 11 patients with late in-the-capsular-bag intraocular lens dislocation following uneventful phacoemulsification cataract surgery were recruited in the study. The dislocated intraocular lens–capsular bag complex was sutured to the iris at two points 180° apart using 9-0 polypropylene sutures on long needles. Results: Mean patient age was 67 ± 6 years. Seven eyes had pseudoexfoliation syndrome, one eye had Marfan syndrome, and another eye had a traumatic cataract; no risk factor was identified for intraocular lens dislocation in two eyes. A capsular tension ring had been implanted during cataract surgery in four eyes. In six eyes, the posterior chamber intraocular lenses were one-piece foldable while the remaining were three-piece intraocular lenses. Compared to the preoperative value, corrected distance visual acuity was significantly improved postoperatively ( p < 0.005). Intraoperative hyphema occurred in two eyes. Pupil ovalization was observed in all eyes. Mean endothelial cell count decreased by 4 ± 1.7% after intraocular lens fixation. The capsular bag–intraocular lens complex was stable and well-centered in the pupillary area in all eyes at the final follow-up examination which was performed 16 ± 4 months postoperatively. Conclusion: Trans-iris fixation is a simple and effective procedure for management of late intraocular lenses–capsular bag complex dislocation, without major complications.