11^th World Congress on Rheumatology, Orthopedics & Sports Medicine July 18-19, 2018 Sydney, Australia

Introduction & Aim: The use of 3-dimensional highly porous acetabular cups is increasing. Their structure and mechanical properties mimic those of natural bone; therefore, they should promote stronger biological fixation. In our experience with total hip arthroplasty, radiolucent lines are observed when a 3-dimensional highly porous cup (stryker tritanium) is used. In this study, we compare the clinical and radiographic results between a tritanium cup and a conventional cup (stryker trident HA) over a short time period. Method: We retrospectively compared consecutive cases of primary total hip arthroplasty using a tritanium cup (130 cases in 118 patients) and a matched cohort of using a trident cap (130 cases in 130 patients) between January 2011 and December 2014. Results: The mean follow-up duration was 41.3 and 38.1 months (p=0.06) for the tritanium and trident groups, respectively. There were significant differences between the groups for radiolucent lines, cup abduction angle and cup-center-edge angle. Radiolucent lines increased in the tritanium group (36% at 3 months and 60% at final follow-up), whereas they decreased in the Trident group (2.5% at 3 months and 0.8% at final follow-up). The occurrence of radiolucent lines was significantly higher in the tritanium group than in the trident group at each follow-up period. Radiolucent lines were seen in 36% of patients in the tritanium group during follow-up, without initial gaps. One cup loosening in the tritanium group was identified at the final follow-up evaluation. Conclusion: Both groups showed successful clinical results over short-term follow-up; however, the tritanium group had a significantly higher rate of radiolucent line occurrence around the cups than did the trident group. Thus, radiolucent lines can occur when using highly porous titanium cups; these lines indicate the possibility of future cup loosening. Longer follow-up and assessment of the results of using this implant are necessary.

A 79-year-old woman with hypertension and osteoporosis presented to the emergency department with right hip pain after slipping and falling on a rainy day. She was taking risedronate for seven years to treat osteoporosis without a drug holiday. Radiography showed a right atypical femoral subtrochanteric fracture and internal fixation was performed using Proximal Femoral Nail Antirotation (PFNA). Autologous iliac crest bone graft was performed simultaneously, because of a high rate of atypical subtrochanteric fracture nonunion. Approximately 10 months postoperatively, the patient presented to the hospital with local heat, pain and swelling at the surgical site on the right hip. The patient had elevated Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) level: 103(0-15) and 192.5(0-5), respectively. X-ray showed some callus formation at the fracture site, but still a nonunion could be observed. A 3-phase bone scan confirmed chronic osteomyelitis at the surgical site, possibly extending to the intramedullary canal. Generally, patients with infected non-unions and in situ implants are treated using a certain process: First, the implant is removed and curettage and debridement are performed using I.V. antibiotics and/or an additional local antibiotic delivery system, such as antibiotics-impregnated cement beads or spacer. The fracture site must simultaneously be protected using an external fixator or splint/cast. After the infection disappears, the nonunion is treated using a stable internal fixation. The patient requires prolonged hospitalization between those two surgeries. Femoral fractures, especially lead the patients to become bedridden which increases the risk for several conditions, including pneumonia, sores, DVT and general weakness. Using an antibiotic cement-coated intramedullary nail was considered to overcome that two-stage operation interval. This case shows an attempt to insert a tibial intramedullary nail in the femur. Applying antibiotic-loaded bone cement to a conventional femoral intramedullary nail causes the volume to become too large, which requires significant reaming of the femur for insertion, thereby weakening the bone. Stable fixation could not be achieved using an antibiotic cement-coated intramedullary K-wire. Conversely, infections may be controlled when bone cement is used without an intramedullary nail, but it can be difficult to successfully treat the nonunion. Therefore, in those cases, an antibiotic cement-coated tibial intramedullary nail could be a highly effective option.