Nailing of proximal ulna fractures: biomechanical comparison of a new locked nail with angular stable plating.

PURPOSE: Proximal ulna fractures are common injuries and frequently treated with angular stable plating. This surgical option shows good functional results. Relevant drawbacks such as large soft tissue exposure, compromised blood supply of fracture fragments and disturbing osteosynthetic material are described. The aim of this study was to compare a new locked proximal ulna nail with angular stable plating in a biomechanical testing setup for extraarticular proximal ulna fractures. METHODS: Ten pairs of sawbones with a Jupiter type IIB proximal ulna fracture (OTA 2U1A3.1) were tested after osteosynthesis with the mentioned implants in a servo-pneumatic testing machine. The testing setup simulates physiological joint motion (0°-90°) under cyclic loading (30-300 N). Primary stability and loosening of both constructs were quantified using micromotion video-analysis after 608 test cycles. RESULTS: The micromotion analysis showed significantly higher primary stability of the locked nail (0.29 ± 0.13 mm) compared to the angular stable plate (0.97 ± 0.30 mm, p < 0.001). Both implants showed a low amount of loosening after completion of the test cycles. The construct with the locked nail (0.08 ± 0.06 mm) showed significantly lower dislocation of the fragments measured at the anterior cortex (plate 0.24 ± 0.13 mm, p < 0.001). CONCLUSION: Nailing of proximal ulna fractures shows significantly higher primary stability and lower loosening compared to angular stable plating in our testing setup.

Medial buttressing of the quadrilateral surface in acetabular and periprosthetic acetabular fractures.

BACKGROUND: In geriatric acetabular fractures, the quadrilateral plate is often involved in the fracture pattern and medially displaced. Open reduction and internal fixation (ORIF) includes reduction of the quadrilateral plate and securing its position. In this study, the concept of medial buttressing in acute and periprosthetic acetabular fractures is evaluated. MATERIALS AND METHODS: Patients, who sustained an acetabular fracture between 2012 and 2018, in whom ORIF with a specific implant for medial buttressing was performed, were included in the study. Patients were divided in two groups; acute acetabular fractures (group 1) and periprosthetic acetabular fractures (group 2). Demographics, type of fracture, surgical approach, type of implant for medial buttressing, comorbidities, general and surgical in-hospital complications and length of hospital stay were recorded retrospectively. The following data were collected from the surviving patients by telephone interview: EQ-5D-5L, SF-8 physical and SF-8 mental before trauma and at follow-up, UCLA activity scale, Parker Mobility Score and Numeric Rating Scale. RESULTS: Forty-six patients were included in this study, 30 males (65.2%) and 16 females (34.8%). Forty patients were included group 1 and six patients in group 2. The median age of patients of group 1 was 78 years. Among them, 82.5% presented with comorbidities. Their median length of in-hospital stay was 20.5 days. 57.5% of patients suffered from in-hospital complications. The concept of medial buttressing was successful in all but one patient. ORIF together with primary total hip arthroplasty (THA) was carried out as a single stage procedure in 3 patients. Secondary THA was performed in 5 additional patients (5/37 = 13.5%) within the observation period. Among surviving patients, 79.2% were evaluated after 3 years of follow-up. Quality of life, activity level and mobility dropped importantly and were lower than the values of a German reference population. SF-8 mental did not change. The median age of patients of group 2 was 79.5 years, all of them presented with one or several comorbidities. The median length of in-hospital stay was 18.5 days. 50% of patients suffered from in-hospital complications. The concept of medial buttressing was successful in all patients. 5 of 6 patients (83.3%) could be evaluated after a median of 136 weeks. In none of these patients, secondary surgery was necessary. Quality of life, activity level and mobility importantly dropped as well in this group. SF-8 mental remained unchanged. CONCLUSION: In geriatric acetabular fractures with involvement and medial displacement of the quadrilateral plate, medial buttressing as part of ORIF proved to be reliable. Only 13.5% of patients of group 1 needed a secondary THA within 3 years of follow-up, which is lower than in comparable studies. Despite successful surgery, quality of life, activity level and mobility dropped importantly in all patients. The loss of independence did however not influence SF-8 mental values.

Nailing of diaphyseal ulna fractures in adults-biomechanical evaluation of a novel implant in comparison with locked plating.

BACKGROUND: Adult forearm fractures require surgical treatment in most cases. Open reduction and internal fixation with plate osteosynthesis is the therapy of choice. Intramedullary fixation offers several advantages compared to plate fixation but is not routinely used. The aim of our study was to compare a newly designed ulna nail with angular stable plating in a biomechanical testing setup of an ulna shaft fracture with a diaphyseal defect. METHODS: Ten pairs of sawbones with a defect osteotomy of the ulna shaft (OTA 2U2C3) were fixed with an interlocked nail or locked plate osteosynthesis. The constructs were tested under four-point bending, torsional loading and axial loading in a servo-pneumatic testing machine to compare the stiffness of both stabilization methods. RESULTS: The nail constructs show lower yet sufficient bending stiffness (62.25 ± 6.64 N/mm) compared to the plate constructs (71.2 ± 5.98 N/mm, p = 0.005). The torsional loading test shows superior stiffness of the plate constructs (0.24 ± 0.03 Nm/deg vs. 0.1 ± 0.01 Nm/deg; p < 0.001), while the axial loading shows superior stiffness of the nail constructs (1028.9 ± 402.1 N/mm vs. 343.9 ± 112.6 N/mm; p < 0.001). CONCLUSIONS: Intramedullary nailing of ulna shaft fractures obtains sufficient but lower stability in bending and torsional loading when compared to rigid angular stable plating and could be an alternative technique to plate fixation. The lower stability and the closed stabilization technique allow for a rapid periosteal healing, which is not present in stiffer constructs.

Percutaneous iliosacral screw fixation after osteoporotic posterior ring fractures of the pelvis reduces pain significantly in elderly patients.

INTRODUCTION: Osteoporotic posterior ring fractures of the pelvis are common injuries in the elderly, but the treatment of these fractures still remains controversial. Percutaneous iliosacral screw fixation is one surgical option if conservative treatment cannot provide sufficient pain reduction. The aim of this study is to provide short-term results of elderly patients with percutaneous screw fixation. METHODS: 30 patients with posterior ring fractures were treated between 12/2009 and 01/2014 with percutaneous iliosacral screw fixation. Patients' mean age was 78.4 years. Concerning short-term outcome, we focused on initial pain level and postoperative pain reduction together with intra- and postoperative complications. RESULTS: The average hospital stay was 23.7 days, with surgical treatment performed after an average of 9.2 days. 90% of our patients were female. All 30 patients had a lower level of pain at discharge compared with admission or immediately prior to surgery. The difference in pain level at admission compared with the pain level upon discharge showed a mean reduction from 6.8 to 1.8 with a statistically significant change (P≤0.001). 24 of 30 patients had no registered complications, one screw malpositioning with postoperative nerve irritation occurred. DISCUSSION: Conventional percutaneous iliosacral screw fixation is a successful operative treatment for elderly patients with persistent lower back pain after unstable posterior ring fractures of the pelvis. Intra- and postoperative complications are rare, so this treatment can be regarded as a safe procedure. LEVEL OF EVIDENCE: IV (retrospective study).