Periprosthetic joint infections (PJI) are challenging complications following arthroplasty. Staphylococci are a frequent cause of PJI and known biofilm producers.

Reoperations for PJI of the hip or knee between 2012 and 2015 performed at Sahlgrenska University Hospital were identified. Medical records were reviewed, and clinical parameters recorded for patients whose intraoperative bacterial isolates had been stored at the clinical laboratory. Staphylococcal strains isolated from reoperations due to first-time PJI were characterised by their ability to form biofilms using the microtiter plate test.

The study group included 49 patients (70 bacterial strains) from first-time PJI, whereof 24 (49%) patients had recurrent infection. Strong biofilm production was significantly associated with recurrent infection. Patients infected with strong biofilm producers had a five-fold increased risk for recurrent infection.

Strong biofilm production was significantly associated with increased antimicrobial resistance and PJI recurrence. This underscores the importance of determining biofilm production and susceptibility as part of routine diagnostics in PJI. Strong staphylococcal biofilm production may have implications on therapeutic choices and suggest more extensive surgery. Furthermore, despite the increased biofilm resistance to rifampicin, results from this study support its use in staphylococcal PJI.

Introduction and Objective

Calcium phosphates are among the most commonly used bone graft substitute materials. Compositions containing predominantly monetite (∼84.7%) with smaller additions of beta-tricalcium phosphate (β-TCP; ∼8.3%) and calcium pyrophosphate (Ca-PP; ∼6.8%) have previously been demonstrated to exhibit osteoinductive properties. Such a multi-component calcium phosphate bioceramic was fashioned in the form of hollowed-out, dome-shaped devices (15 mm diameter, 4 mm height), each reinforced with a 3D printed Ti6Al4V ELI frame. With the aim to induce bone formation beyond the skeletal envelope, these devices were investigated in vivo using a sheep (Ovis aries) occipital bone model.

Introduction: The aim of this study is long term comparison of hydroxyapatite (HA) coating and porous (PO) coating in an identical stem design.

Material and Methods: 100 consecutive hips from 86 patients scheduled for uncemented primary arthroplasty were quasi-randomized to receive a titanium-alloy anatomic PROFILE stem (DePuy, Warsaw, IN), HA coated in every second hip and PO coated in the remainder 50 hips. Patients receiving bilateral total hip arthroplasty were implanted an HA coated stem in one and a PO coated in the contralateral hip. All surgeries were performed by the posterolateral approach by 2 surgeons (the author PBT being one of them). The acetabular component was either an AML+ or a Duraloc 300 implant with a cobalt chrome 28mm head (DePuy, Warsay, IN).

15 to 18 years postoperatively these patients and their hip radiographs were examined by an independent observer (WD) to establish the long term survival, clinical and radiographical performance of this stem and especially to compare the two coatings. The Harris hip score was employed for clinical evaluation

Results: 16 years and 3 months (range 15y 0m – 17y 8m) postoperatively 21 patients with 23 hips had died and 4 hips (2HA/2 PO) had been revised. This leaves 62 patients with 73 hips (34 HA/39 PO) for evaluation. Life tables showed 18 years cumulative survival (free of revision of any reason) of 95.8% for HA and 95.5% for PO. 18 years cumulative survival (free of revision for aseptic loosening) were 95.8% for HA and 97.5% for PO. There were no infections in either group. Mean HHS was 83.4 ± 14.8 in HA and 86.8 ± 11.5 in PO (P = 0.32). Mean pain score was 39.1 ± 9.4 in HA and 40.9 ± 6.7 in PO (P = 0.69). Radiographs showed osseointegration of the stem except in 1 HA and in 2 PO stems. Lucencies/osteolytic scalloping were only seen in zone 1 and 7. Significant bone remodeling changes were seen. Ectopic ossification developed in 1/3 of hips non progressive stem subsidence of 2 mm were measured in a few hips.

Conclusion: This prospective quasi-randomized study show excellent long term performance and survival of the titanium-alloy anatomic PROFILE stem in primary hip arthroplasty in patients < 66 years with no significant differences between HA and PO coating.