Introduction

Trabecular Titanium is a biomaterial characterized by a regular three-dimensional hexagonal cell structure imitating trabecular bone morphology. Components are built via Electron Beam Melting technology in aone- step additive manufacturing process. This biomaterial combines the proven mechanical properties of Titanium with the elastic modulus provided by its cellular solid structure (Regis 2015 MRS Bulletin). Several in vitro studies reported promising outcomes on its osteoinductive and osteoconductive properties: Trabecular Titanium showed to significantly affect osteoblast attachment and proliferation while inhibiting osteoclastogenesis (Gastaldi 2010 J Biomed Mater Res A, Sollazzo 2011 ISRN Mater Sci); human adipose stem cells were able to adhere, proliferate and differentiate into an osteoblast-like phenotype in absence of osteogenic factors (Benazzo 2014 J Biomed Mater Res A). Furthermore, in vivo histological and histomorphometric analysis in a sheep model indicated that it provided bone in-growth in cancellous (+68%) and cortical bone (+87%) (Devine 2012 JBJS). A multicentre prospective study was performed to assess mid-term outcomes of acetabular cups in Trabecular Titanium after Total Hip Arthroplasty (THA).

Aim

The aim of the study is to evaluate the specificity and sensibility of leukocyte esterase for the diagnosis of periposthetic joint infection (PJI).

The purpose of this study was to evaluate the accuracy of the sonication fluid cultures (SFC) for the diagnosis of prosthetic joint infection and compare it with frozen section and periprosthetic tissue cultures.

108 patients underwent revision or explantation procedure for any reason. Frozen sections of intraoperative specimen were analized and multiple periprosthetic samples (at least 5) were collected and cultured. All explanted prosthesis components were subject to sonication and cultured. All cultures were incubated for 14 days.

PJI was diagnosed in 52 patients (48%). Sonication achieved the highest sensivity with 95% and specificity of 98%. Frozen section showed low sensivity (44%) and specificity (80%) and periprosthetic tissue cultures showed sensivity of 75% and specificity of 98%.

Sonication fluid culture is a cheap, easy, accurate and sensitive diagnostic method and helps to detect about 30% more PJI compared to frozen section and 16% more compared to periprosthetic tissue cultures. It also detect about 25% more pathogens than periprosthetic tissue cultures

The clinical success and long-term outcomes of total knee arthroplasty (TKA) depend not only on the accuracy of femoral and tibial components positioning, but also on the restoration of a proper mechanical axis (MA). Coronal and rotational mal-alignment may affect significantly the final result of a knee replacement. Patient specific cutting guides and intra-operative Computer-Assisted Surgery (CAS) have recently been introduced as options to improve implant alignment during TKA. The purpose of this study was to compare the alignment accuracy and implant positioning of Patient Matched technique to CAS system in patients with primary TKA.

A cohort of 68 consecutive patients who underwent TKA was enrolled for this study: 34 patients received a TKA using CAS system while 34 patients received a TKA using a MRI-based Patient Matched system. Mechanical axis and kinematics were digitally measured pre- and post-operatively in all knees using the intra-operative navigation system but data were blinded for the operating surgeon in the Patient Matched group. A post-operative CT-scan evaluation was performed in all patients to analyse the prosthetic components alignment (coronal, sagittal and axial alignment according to Perth Protocol from CT-scan). CT-scan measurements were used as landmarks as this tool is considered the gold standard. MA, posterior tibial slope (PTS) and femoral component rotation (FCR) in CAS group were compared to data of Patient Matched group. All patients also underwent a clinical evaluation with Knee Society Score (KSS) and Knee injury and Osteoarthritis Outcome Score (KOOS) at 6 and 12 months of follow up.

KSS, KOOS and range of motion were comparable in the two groups after surgery. Operative time was significantly shorter in the Patient Matched group. No differences were found regarding complications rate.

Mean angles, respectively for CAS and Patient Matched groups, were the following: MA was 1,7° (SD 0,9°) vs 0.8° (SD 2.1°); PTS was 3.1° (SD 0.9°) vs 3.4° (SD 2.1°); FCR was 1.5° (SD 2.2°) vs 1.36° (DS 1.2°). The outcomes of the CT scan evaluation were the following: MA was 1.5° (SD 0.8°) vs 1.0° (DS 1.5°); PTS was 2.3° (SD 0.8°) vs 3.0° (SD 2.6°); FCR was 0.4° (SD 0.8°) vs 0.2° (SD 0.3°). MA was within 3° of neutral alignment in 94% of patients for CAS group and in 97% of knees for Patient Matched group.

After a short follow up, there weren't statistically significant differences between CAS and Patient Matched techniques as regards clinical and functional scores. Both the systems achieved the goal of neutral alignment within 3° of varus and valgus. We only observed greater precision for Patient Matched technique in optimizing femoral component rotation. Actually it is unpredictable if this difference may determine long term effects.

Patient Matched technique and CAS for TKA surgery will certainly continue to have an impact in the future. Studies are needed to define which technique is better, in terms of long term results, failure rate and cost-effectiveness.

Introduction

Trabecular Titanium™ is a highly porous biomaterial with a regular hexagonal cell structure, which has shown excellent mechanical properties. Several in vitro studies reported promising data on its osteoinductive and osteoconductive properties. Furthermore, it has demonstrated in vivo to enhance bone in-growth. Aim of this multicentre prospective study was to assess Trabecular Titanium™ osseointegration by measuring change in bone mineral density (BMD) around a cementless DELTA-TT cup with dual-emission X-ray absorptiometry (DXA).

Trabecular TitaniumTM is a tri-dimensional material composed by multi-planar regular hexagonal cells and characterised by a highly open porosity that has been studied to optimise bone osteointegration. The aim of this study is to evaluate bone remodelling measuring BMD changes around an acetabular cup made from Trabecular TitaniumTM in primary total hip arthroplasty (THA).

Between February 2009 and December 2010, 89 patients (91 hip) underwent primary THA with a modular acetabular cup in Trabecular TitaniumTM (DELTA-TT cup, Limacorporate, Villanova di San Daniele, Italy). The average age was 63.5± 9.4 years, the average height and weight were 75.9± 12.9 kg and 168.8± 8.9 cm, respectively (av. BMI 26.8± 4.2). There were 46 (51.7%) males and 43 (48.3%) females affected by primary coxarthrosis in 80 (87.9%) cases, avascular necrosis in 5 (5.5%), posttraumatic coxarthrosis in 3 (3.3%), dysplasia in 2 (2.2) and oligoarthritis in 1 (1.1%) case. The study includes the clinical evaluation with Harris Hip Score (HHS) and SF-36, radiographic evaluation and dual-energy x-ray absorptiometry (DEXA) analysis preoperatively and postoperatively at 1 week, 3, 6, 12 and 24 months.

Preliminary results are currently available for 47 patients at 12 months, 68 at 6 months and 80 at 3 months. The average HHS significantly improved from 48.7± 14.99 preoperatively to 93.8± 5.91 at 12 months, with a constant progression in the intermediate follow-ups. All patients showed a significant ROM increase, with an average flexion from 86.6°± 15.9° preoperatively to 105°±13.14 at 12 months. Sf-36 highlighted a satisfactory improvement of general health status from an average preoperative value of 50.8± 18.7 to 80.7± 12.9 at 12 months (from 42.9 to 80.1 for physical health; from 58.4 to 81.3 for mental one). All cups were stable at 12 months with no radiolucent lines. Preliminary DXA analysis reported an initial bone mineral density decrease from 1 week baseline values (BMD R1: 1.40± 0.37; R2: 1.20± 0.45; R3:1.16± 0.31) to 3 months (BMD R1: 1.31± 0.41; R2: 1.17± 0.3; R3: 1.06± 0.37) followed by BMD recovery up to initial values (BMD R1: 1.37± 0.3; R2:1.18± 0.34; R3: 1.12± 0.36) at 12 months.

Trabecular TitaniumTM demonstrates a good primary and secondary stability. Preliminary densitometric outcome confirms an optimal osseointegration of the DELTA-TT cup and early clinical and patient subjective results are very promising at a short term follow-up. However, the completions of follow-up evaluation are necessary to draw a conclusive analysis.

INTRODUCTION

Trabecular Titanium™ is an innovative material characterised by an high open porosity and composed by multi-planar regular hexagonal cells. It is not a traditional coating and its tri-dimensional structure has been studied to optimise osteointegration. Furthermore, it has excellent mechanical properties, as a very high tensile and fatigue resistance and an elastic module very similar to the that of the trabecular bone. The aim of this study is to evaluate the osteointegration and bone remodelling measuring the longitudinal pattern of change in BMD around a cementless acetabular cup made from Trabecular Titanium™ (Delta TT cup, Lima Corporate, Italy) in primary total hip arthroplasty (THA).