Aims

The aim of this study was to determine the fracture haematoma (fxH) proteome after multiple trauma using label-free proteomics, comparing two different fracture treatment strategies.

In polytrauma patients invasive surgeries can potentiate the posttraumatic systemic inflammation thus increasing the risk of multi organ dysfunction. Therefore, fractures are initially treated by external fixators, which later are replaced by intramedullary nails. We showed that a severe trauma impaired the healing of fractures stabilized by external fixation. Here we studied, whether the conversion to an intramedullary nail increases posttraumatic inflammation and leads to further impairment of healing.

44 rats received a femur osteotomy stabilized by an external fixator (FixEx). Half of the rats underwent a thoracic trauma (TXT) at the same time. After 4 days the fixator was replaced by an intramedullary nail (IMN) in half of the rats of each group. The rats were killed after 40 and 47 days. C5a serum levels were measured 0, 6, 24, and 72h after the 1st as well as the 2nd surgery. The calli were evaluated by three-point-bending test, μCT and histomorphometry.

The TXT significantly increased serum C5a levels after the 2nd surgical intervention. After 40 days the switch from FixEx to IMN significantly decreased bending stiffness in rats with and without TXT. After 47 days flexural rigidity in rats subjected to conversion was significantly decreased compared to rats treated only with a FixEx, particularly in combination with TXT.

This study showed that after a severe trauma the conversion of the fixation could provoke a second hit and contribute to delayed fracture healing.

There is evidence that fracture healing is delayed in severely injured patients. We recently demonstrated that a blunt chest trauma, which induced posttraumatic systemic inflammation, considerably impaired fracture healing in rats. Because the complement anaphylatoxin C5a is an important trigger of systemic inflammation, we tested the hypothesis, whether the impairment of fracture healing observed after a severe trauma resulted from systemically activated complement.

16 male Wistar rats received a thoracic trauma and a femur osteotomy stabilized by an external fixator. Immediately and 12 h after the trauma, half of the animals received a C5aR-antagonist to prevent the C5a-dependent systemic inflammation. Control rats received a nonsense peptide, which does not provoke any biological effect. The animals were killed after 35 days and the calli were analyzed by three point bending testing, μCT and histomorphometry. Statistics: Mann-Whitney U test, level of significance to p<0.05.

The treatment with the C5aR-antagonist increased flexural rigidity significantly by 55%, improved bony bridging of the fracture gap and led to a slightly larger and qualitatively improved callus as evaluated by μCT and histological measurements.

This study shows, that the immunomodulation by a C5aR-antagonist significantly reduced the deleterious effects of a thoracic trauma on fracture healing. C5a could possibly represent a target to prevent delayed bone healing in patients with severe trauma.

Since osteoimmunology is gaining increasingly interest and evidence for involvement of complement in bone biology was found, the role of complement in bone biology and fracture healing was evaluated.

After characterizing the bone phenotype, a fracture healing experiment with C3- and C5- deficient mice was performed. After osteotomy of the right femur and external fixation, healing was analyzed after 1, 3, 7 and 21 days. Bone characterization revealed a reduced number of osteoclasts in C5-deficient animals with a significantly reduced resorption activity. While bone mineral density was significantly higher in complement-deficient strains, stiffness was significantly reduced. After 21 days of fracture healing, C5-deficient animals showed reduced stiffness and a smaller callus volume compared to controls. Interestingly, C3- more than C5-deficient animals showed reduced bone formation. Altogether, bone phenotype of complement-deficient animals resembles a mild form of osteopetrosis.

This might be due to the resorption defect seen in C5-deficient mice. A reason for the minor involvement of C3-deficient mice compared to the C5-deficient animals could be the cross-talk between the coagulation cascade with side activation of complement factor C5 by thrombin.

These results indicate for the first time an essential role of complement in bone biology and fracture healing. Future studies should focus on the molecular basis of complement involvement and the osteoclastic resorption defect.

Background

Continual implant stability is an important factor for the long-term success of cementless hip replacements. The increasing lifespan of patients causes a higher frequency of osteoporosis which may result in implant loosening due to bone loss. This study aimed to evaluate stability of long living implants in patients with advanced age.

Objectives

To investigate the differences of open reduction and internal fixation (ORIF) of complex AO Type C distal radius fractures between two different models of a single implant type.

For many decades ankle fusion has been the only option for treatment of symptomatic osteoarthritis of the ankle joint. From the late 60’s on the crusade of joint replacement for hip and knee led to successful functional restoration for severe destruction of these joints. Because of a lack of understanding the biomechanical principals of the ankle a similar approach in reconstructing the ankle arthritis was doomed to fail. On the other side very good functional outcome after fusion of the ankle seemed to make needless further development. Although first encouraging results with non-constrained designs and cementless fixation were obtained in mid-late 70’s a wider acceptance within the orthopaedic society was found only almost 20 years later whereas today many surgeons wouldn’t give up the ankle arthroplasty for several indications. Despite good and very good midterm results we still need to understand limits and further develop operative techniques especially soft-tissue balancing.

In our institution we have been using TAR since 1995 on a regular basis and by now overlook a total of almost 400 TAR’s. The experience with different designs (Agility, S.T.A.R. and Buechel-Pappas) led to the development of the Mobility-TAR in collaboration with two surgeons from England and the U.S. It is a 3-component TAR, non-constrained. As a unique feature the instrumentation allows an accurate centring of the implants both in the frontal and the saggital plane. In a prospective trial in Wrightington and Zurich we clinically and radiographically evaluate the outcome. The first 42 cases in Zurich with a follow-up of more than 1 year showed a significant pain reduction from av. 8.1 on a visual analogue scale to av. 1.4 after one year. The ROM assessed radiographically could be improved from 26° preoperatively to 33° after one year. We have seen 4 fractures/osteotomies of the medial malleolus and one neuropathy of the tibial nerve as intraoperative complications. Postoperative complications included two superficial wound healing problems, one deep infection and finally two stress fractures of the medial malleolus. One case had to be revised because of aseptic loosening after 6 months. All but one of the first 42 patients would undergo the same procedure again.

The first results are encouraging because of good overall results with significant pain reduction and good ROM combined with only few complications.

Aims: The purpose of our retrospective case-series study was to determine factors that inßuence the long-term outcome of high tibial osteotomy (HTO). Methods: Between 1984 and 1990, 164 patients received an HTO for medial unicompartmental OA associated with varus deformity of the knee. All the HTOs were performed with a modiþed technique of Weber and Coventry. 39 knees in 35 patients were assessed at an average time of 13.5 years by an independent clinician. Patients were evaluated by the Clinical Rating System of the Knee Society, and underwent a complete radiological exam. Results: The results of the function score from patients with no further treatment were good to excellent in 71.5% of the cases and fair in only 10.7%. There were 17.8% poor results. There was a progression in radiological evidence of arthrosis after 10 to 15 years compared to the mid-term results after three to þve years. Patients with a previous meniscectomy had a statistically signiþcant worse function score (p=0.05) than patients who underwent HTO only because of malalignment induced OA. When the size of the osteotomy wedge was bigger than 20¡, there was a signiþcantly worse function score (p=0.049). Conclusion: The long-term results of this study conþrm, that treatment of varus gonarthrosis with HTO generally yield a long time (mean time of survival was 11.5 years) of pain-reduction and a good function for most of the patients.

We studied the fixation of a cementless titanium femoral prosthesis partially coated with hydroxyapatite ceramic (HAC) 10.4 months after implantation. Histomorphological investigation showed extensive new bone formation between the HAC coating and the bone bed; morphometry showed bone contact indices of up to 91.60%. There were a number of resorption lacunae on the HAC coat with depths of up to 76.6 microns and widths of up to 453 microns. Our results confirmed that considerable bone remodelling had taken place and that the apatite-coated prosthesis had united with bone despite the lack of appreciable immediate press-fit. Hydroxyapatite particles which had been released did not appear to show any negative effects on the stability of the implant.