Rare implant-specific complications of the MoPyC radial head prosthesis.

BACKGROUND: According to currently available data, the clinical short-term results of the MoPyC radial head prosthesis (Bioprofile, Tornier, Montbonnot-Saint-Martin, France) seem favorable. However, we have encountered several implant-specific complications in recent years. Hence, this case series reports rare complications after radial head arthroplasty with the MoPyC prosthesis to make surgeons aware of their existence and to provide information about the underlying cause and possible salvage strategies. METHODS: A retrospective chart review from 2011 to 2016 was conducted to identify all adult patients with a minimum 2-year follow-up who underwent or were referred after radial head arthroplasty with the MoPyC radial head prosthesis and experienced implant-related complications. RESULTS: Five patients with 7 implant-related complications were found. One patient experienced breakage of the pyrocarbon head. In another patient, breakage of the stem and-after revision surgery-partial breakage were observed. Disassembly of the prosthesis was seen in 1 case. Extensive periprosthetic stress shielding was seen in 3 patients resulting in symptomatic loosening (1), periprosthetic radial neck fracture (1), and stem migration (1). CONCLUSIONS: Whereas clinical short-term results of the MoPyC radial head prosthesis are satisfactory, rare implant-related complications can occur. Surgeons should be aware of these complications as they may lead to a poor outcome.

Dynamic contrast-enhanced magnetic resonance imaging can assess vascularity within fracture non-unions and predicts good outcome.

OBJECTIVES: To prospectively evaluate whether dynamic contrast-enhanced (DCE) MRI can assess vascularity within non-unions and predicts clinical outcome in combination with the clinical Non-Union Scoring System (NUSS). METHODS: Fifty-eight patients with non-unions of extremities on CT underwent 3-T DCE MRI. Signal intensity curves obtained from a region-of-interest analysis were subdivided into those with more intense contrast agent uptake within the non-union than in adjacent muscle (vascularised non-union) and those with similar or less contrast uptake. The pharmacokinetic parameters of the Tofts model K trans, K ep, iAUC and V e were correlated with union at CT 1 year later (n = 49). RESULTS: Despite inserted osteosynthetic material, DCE parameters could be evaluated in 57 fractures. The sensitivity/specificity of vascularised non-unions as an indicator of good outcome was 83.9%/50.0 % compared to 96.8%/33.3% using NUSS (n = 49). Logistic regression revealed a significant impact of NUSS on outcome (P = 0.04, odds ratio = 0.93). At first examination, median iAUC (initial area under the enhancement curve) for the ratio non-union/muscle was 10.28 in patients with good outcome compared with 3.77 in non-responders (P = 0.023). K trans, K ep and Ve within the non-union were not significantly different initially (n = 57) or 1 year later (n = 19). CONCLUSIONS: DCE MRI can assess vascularity in fracture non-unions. A vascularised non-union correlates with good outcome. KEY POINTS: • Dynamic contrast-enhanced magnetic resonance imaging can assess vascularity within bony non-unions. • Vascularised ununited fractures appear better at 1-year CT than poorly vascularised fractures. • Non-union healing after osteosynthesis or osteoinductive drugs fundamentally requires vascularity. • DCE MRI predicts treatment outcome better than the clinical Non-Union Scoring System. • DCE MRI is clinically feasible to predict treatment outcome in bony non-unions.

Kyphoplasty for patients with multiple myeloma is a safe surgical procedure: results from a large patient cohort.

INTRODUCTION: Only in recent years has balloon kyphoplasty gained significance in the treatment of vertebral fractures as an adequate minimally invasive vertebral stabilization technique. Kyphoplasty has also increasingly been used to treat vertebral osteolyses caused by multiple myeloma (MM). PATIENTS AND METHODS: In our cohort of 76 patients with MM with a total of 190 vertebral fractures treated with kyphoplasty, we performed a 30-day postoperative analysis of cement leakage, neurologic symptoms, pulmonary embolism, and infections. RESULTS: Painful osteolytic or fractured vertebrae or even imminent vertebral instability caused by osteolyses were seen as indications for kyphoplasty. One case of pulmonary embolism was observed because of cement leakage as the only postoperative complication. CONCLUSION: By careful interdisciplinary indication setting and a standardized treatment model, kyphoplasty presents a very safe and effective procedure for the treatment of vertebral osteolyses and fractures caused by MM.

1150 kyphoplasties over 7 years: indications, techniques, and intraoperative complications.

In our cohort of 555 patients with a total of 1150 vertebral fractures treated with kyphoplasty we performed a 30-day postoperative analysis of cement leakage, neurological symptoms, pulmonary embolism, and infections. In our department, 22% of kyphoplasties were performed with calcium phosphate cement and the remainder with polymethylmethacrylate. All patients were initially assessed by an interdisciplinary kyphoplasty colloquium, composed of consultants in traumatology, radiology, and endocrinology. Indications included fresh traumatic vertebral fractures; painful sintered osteoporotic vertebrae; osteolysis and painful vertebral body collapse caused by multiple myelomas; and lymphomas and pathological fractures due to metastases of malignant tumors (prostate cancer, breast cancer, ovarian cancer, and malignant melanoma) or benign vertebral tumors (hemangioma). Contraindications included patients with instability of the posterior wall and/or pedicles, an infection of the fractured vertebra, a severe hemorrhagic diathesis, known allergies to the cements, pregnancy, and ASA score of 4. The standard postoperative computed tomography scan of the kyphoplasty-treated vertebrae revealed a dorsal cement leakage in 38 vertebrae representing 3.3% of all levels. A permanent monoparesis of the left leg, 2 cases of temporary neurological deficits, 2 cases of hemorrhage, and 1 asymptomatic pulmonary embolism were observed as postoperative complications. We observed no complications relating to polymethylmethacrylate described in the literature. By careful interdisciplinary indication setting and a standardized treatment model, kyphoplasty presents a safe and effective procedure for the treatment of various vertebral fractures.