Mid-term implant survival, functional and radiological results and mechanical complications of mega-prosthetic reconstruction around the knee with the PENTA® system

Aim Mega-prosthetic reconstruction is the most common treatment method for massive osteoarticular defects caused by tumor resection around the knee. The new implant is a highly modular rotational-hinged megaprosthesis system with a distinct pentagonal stem geometry and variable implantation options. The aim of this study is to present the mid-term implant survival characteristics, functional and radiological results and mechanical complication profile of the new megaprosthesis. Methods One hundred and one mega-prosthetic knee reconstruction procedures in 90 patients (M/F: 51/39) utilizing the new implant system were retrospectively analyzed. In 68 patients, the megaprosthesis was used for primary reconstruction following tumor resection while it was used for revision of other implants in 22. The mean age was 28.5 (7–66) years and the mean follow-up was 59.2 (24–124) months. The most common primary pathology was osteosarcoma with 63–70% patients, the most common anatomical site of involvement was the distal femur with 56–62% patients. Results Henderson Type 2 failure (aseptic loosening) was seen in only 2–2.2% patients while Type 3 (structural failure) was seen in 29–32.2% Although the 5-year anchorage survival rate was 94.3%, overall mechanical implant survival was 76.1% at 5 years due to a relatively high failure rate in the first-generation hinge mechanism of the implant. The 5-year hinge survival rate demonstrated a significant improvement rate from 61.7% to 87.2% between the first and second generations of the implant (p = 0.027). The mean MSTS score was 24 out of 30 (14–29). The mean cumulative ISOLS radiographic score for index megaprosthesis operations was 19.7 (12–24), which corresponded to excellent outcome. Conclusion The new megaprosthesis system is a reliable choice for the reconstruction of tumor-related massive osteoarticular defects around the knee. Although long-term follow-up is necessary for a definitive evaluation of the implant's survival characteristics, midterm follow-up yields exceptional anchorage properties related to pentagonal stem geometry with very good functional outcomes.

Zimmer Natural Nails in the Treatment of Unstable Intertrochanteric Fractures: A Longitudinal Study

Introduction:Cephalomedullary nails are preferred over intramedullary nails for internal fixation of unstable intertrochanteric fractures; however, they are associated with complications as they do not match the anatomy of the proximal femur to a great extent. Aim: To investigate functional and radiological results of Zimmer natural nails in the management of unstable intertrochanteric fractures. Materials and Methods: A longitudinal prospective study of 99 patients with unstable intertrochanteric fractures was carried out. All patients underwent closed reduction and internal fixation with 180 mm short Zimmer natural nails. Follow-up visits were scheduled for six weeks, three months, and six months for radiological healing and mobility measurements using RUSH and Parker scores, respectively. Statistical analysis was performed using Chi-square and ANOVA. Results: Mean age of patients was 69.77±11.47 years with a male to female ratio of 1:1. A majority of patients had co-morbidities like diabetes mellitus and hypertension. Average duration of surgery was 58.38 minutes with no statistically significant difference among the different categories of unstable intertrochanteric fractures. Fixation of fractures with Zimmer natural nails increased Parker score and RUSH score consistently with each follow-up visit (p<0.05). There were no postoperative complications in 93.94% cases. Conclusion: This study emphasised good functional and radiological results of Zimmer natural nails in the treatment of unstable intertrochanteric fractures.

Functional and radiological results of partial capitate shortening osteotomy in the treatment of Kienböck’s disease

This study assessed the functional and radiological results of partial capitate shortening osteotomy in the treatment of Lichtman stage 2 and 3A Kienböck's disease. Nineteen patients who underwent partial capitate shortening osteotomy between 2014 and 2017 were included. Functional and radiological parameters were assessed both pre- and postoperatively. The mean age was 35 years and the mean follow-up was 16 months. Pain scores, wrist range of motion, hand and finger strength, carpal height ratio and lunate height were significantly improved compared with their preoperative values. Sixteen patients were able to return to work. Ten of them had complete and six had partial revascularization. The mean time taken to return to work was 62 days. No vascularity was achieved in three patients who were unable to return to work. Partial capitate shortening osteotomy is effective in the treatment of stage 2 and 3A Kienböck's disease with successful results both functionally and radiologically. Level of evidence: IV