Ulrich Stöckle

Stabilisation of periprosthetic fractures with angular stable internal fixation: a report of 13 cases

Introduction: Periprosthetic fractures of the femur present a challenging surgical problem. The aim of this study was to retrospectively evaluate the outcome of periprosthetic fractures stabilised with an angular stable, less invasive stabilisation system (LISS). Patients and methods: Thirteen patients (ten total hip-, two total knee-, one total hip- and knee-arthroplasty) with periprosthetic fractures were treated with the LISS internal fixator (in ten cases minimal invasive). Six patients had previous operations due to periprosthetic fractures. The average follow-up period was 20 months, follow-up rate 85%. Results: All fractures showed radiographic fracture healing without implant loosening. Except one patient, all patients had returned to their pre-operative activity level. No early post-operative complications were seen. There was one implant failure after 4 months and two cases of malunion. Conclusion: The cases showed the internal fixator to be effective for the stabilisation of periprosthetic fractures, even in cases of poor bone quality with good functional outcomes. The internal fixator, with the option of minimal invasive application, is the preferred method of osteosynthesis in periprosthetic fractures.

Clinical comparison of the second and third generation of intramedullary devices for trochanteric fractures of the hip—Blade vs screw

With industrial societies getting older the incidence of femoral fractures is increasing. Complication rates up to 20% have led to a continuous improvement of intramedullar nailing systems and the third generation of implants is in clinical application. They seem superior to the second generation. But as clinical data is still fragmentary, we wanted to compare a second generation implant, the Proximal Femur Nail with three devices of the third generation: the Gleitnagel, Trochanter Fixation Nail and the Proximal Femur Nail Antirotation with a clinical study. We analysed whether fracture reduction and implant position could possibly be indicators for implant complications. Patients with a trochanteric fracture type A1-A3 (AO/ASIF classification) admitted at the department of traumatology Augsburg were enrolled. Postoperative X-rays were analysed in the matter of fracture reduction for the fracture gap, the Garden Alignment Index and for the matter of implant position in the femur head with the cleaveland zones and the Tip Apex Distance. 322 patients were enrolled. Most frequent was the A2 (n=240) and the A3 type of fracture (n=80) followed by A1 (n=29). Time to hospital discharge was 17 days (9/25), 12 patients died (3.2%). The complication rate (cutting out) in the third generation was lower (2.5-7%) than in the second generation (14%). The postoperative range of mobilisation compared to the old social status was in the groups with 34% similar after 3 months. The third generation nails are safe and reliable implants. Compared with second generation devices, fewer complications are observed. A correlation might be seen in the postoperative X-rays between the fracture reduction or implant position and implant related mechanical complications (cutting out).

Gentamycin delivered from a PDLLA coating of metallic implants: In vivo and in vitro characterisation for local prophylaxis of implant-related osteomyelitis

Locally applied antibiotics support prophylaxis of highly feared implant associated infections. Implant coatings with poly(D,L-lactide) (PDLLA)/gentamicin seem to be a promising approach. Aims of this study were to analyse the release kinetics of gentamicin in vivo, in vitro, to analyse the antibacterial efficacy,the resistance development and its impact on osteoblasts. For the in vitro release experiments titanium implants were coated with PDLLA/gentamicin and the antibiotic release in aqueous solution was analysed at 20 time points (from 10 s to 110 days). For the in vivo experiments PDLLA/gentamicin-coated kirschner wires were implanted in the tibiae of 18 rats. Gentamicin concentration in the bone was analysed at several time points (n = 3 each, 1 h to 7 days). Bactericidal efficacy, bacterial adhesion on the implants and resistance development were tested. AP activity, cell count and CICP expression of osteoblasts were analysed. Gentamicin was released rapidly with an initial burst in aqueous solution and followed by a slow release. Similarly, in vivo gentamicin concentration reached a high peak initially followed by a decrease to a low level. No development of resistance was observed in the investigated setting, the antibacterial efficacy was not affected by the coating process and significantly fewer bacteria were attached to the implant. Osteoblasts were not negatively affected by the gentamicin released from the coating. PDLLA/gentamicin coating resulted in a desired antibiotic peak concentration within the bone. Bacterial adhesion was successfully prevented. No bacterial resistances were developed. This coating seems to be a suitable supplement for prophylaxis of implant-associated infections.

Comparative analysis of phase I and II enzyme activities in 5 hepatic cell lines identifies Huh-7 and HCC-T cells with the highest potential to study drug metabolism

Primary human hepatocytes (hHeps) are still gold standard to perform human drug metabolism studies, but their availability is limited by donor organ scarcity. Therefore, hepatoma cell lines are widely used as alternatives, although their phases I and II drug-metabolizing activities are substantially lower compared with hHeps. The major advantage of these cell lines is immediate availability, standardized culture conditions and unlimited life span. Therefore, the aim of this study was to investigate the drug-metabolizing profile of five human hepatoma cell lines (HepG2, Hep3B, HCC-T, HCC-M and Huh-7) over a culture period of 10 passages. Fluorescent-based assays for seven different cytochrome P450 (CYP) isoforms and seven different phase II enzymes were performed and compared with enzymatic activities of hHeps. CYP activities were much lower in the cell lines (5–15% of hHeps), whereas phase II enzyme activities that are involved in buffering oxidative stress (e.g., Glutathione-S-transferase) reached levels comparable with hHeps. Furthermore, phases I and II enzyme activities in hepatoma cell lines vary strongly during culture time. Interestingly, the most constant results were obtained with Huh-7 cells. Huh-7 cells as well as HCC-T cells exhibited a drug-metabolizing profile closest to hHeps between passages two and four. Toxicity studies with Diclofenac, Paracetamol and Verapamil in both cell lines show dose–response characteristics and EC50 values similar to hHeps. Therefore, we propose that due to the more consistent results throughout the passages, Huh-7 could be an alternative system to the limitedly available hHeps and frequently used HepG2 cell line in the study of drug metabolism.

TGF-β1 As Possible Link between Loss of Bone Mineral Density and Chronic Inflammation

Background The TGF family plays a key role in bone homeostasis. Systemic or topic application of proteins of this family apparently positively affects bone healing in vivo. However, patients with chronic inflammation, having increased TGF-β1 serum-levels, often show reduced bone mineral content and disturbed bone healing. Therefore, we wanted to identify intracellular mechanisms induced by chronic presence of TGF-β1 and their possible role in bone homeostasis in primary human osteoblasts. Methodology/Principal Findings Osteoblasts were isolated from femur heads of patients undergoing total hip replacement. Adenoviral reporter assays showed that in primary human osteoblasts TGF-β1 mediates its signal via Smad2/3 and not Smad1/5/8. It induces proliferation as an intermediate response but decreases AP-activity and inorganic matrix production as a late response. In addition, expression levels of osteoblastic markers were strongly regulated (AP↓; Osteocalcin↓; Osteopontin↑; MGP↓; BMP 2↓; BSP2↓; OSF2↓; Osteoprotegerin↓; RANKL↑) towards an osteoclast recruiting phenotype. All effects were blocked by inhibition of Smad2/3 signaling with the Alk5-Inhibitor (SB431542). Interestingly, a rescue experiment showed that reduced AP-activities did not recover to base line levels, even 8 days after stopping the TGF-β1 application. Conclusions/Significance In spite of the initial positive effects on cell proliferation, it is questionable if continuous Smad2/3 phosphorylation is beneficial for bone healing, because decreased AP-activity and BMP2 levels indicate a loss of function of the osteoblasts. Thus, inhibition of Smad2/3 phosphorylation might positively influence functional activity of osteoblasts in patients with chronically elevated TGF-β1 levels and thus, could lead to an improved bone healing in vivo.

The possible use of stem cells in regenerative medicine: dream or reality?

Stem cells are one of the most fascinating areas in regenerative medicine today. They play a crucial role in the development and regeneration of human life and are defined as cells that continuously reproduce themselves while maintaining the ability to differentiate into various cell types. Stem cells are found at all developmental stages, from embryonic stem cells that differentiate into all cell types found in the human body to adult stem cells that are responsible for tissue regeneration. The general opinion postulates that clinical therapies based on the properties of stem cells may have the potential to change the treatment of degenerative diseases or important traumatic injuries in the “near” future. We here briefly review the literature in particularly for the liver, heart, kidney, cartilage, and bone regeneration.

Digital planning of high tibial osteotomy. Interrater reliability by using two different software

PurposeThe purpose of the study was to determine the interrater reliability as well as the correlation of mediCAD® and PreOPlan® in deformity analysis and digital planning of osteotomies.MethodsDigital radiographs were obtained from 81 patients planned to undergo an open wedge high tibial osteotomy. The JPEG files of the radiographs were imported to landmark-based software. Deformity analysis and planning of correction were performed by 1 experienced and 2 unexperienced observers. Osteotomy planning was aimed at correction to the predefined mechanical tibiofemoral angle of 3° valgus leg alignment. The interrater reliability of measurements was assessed using intraclass correlation coefficients (ICCs) and the confidence interval.ResultsThe ICC of PreOPlan® was from 0.841 (mechanical lateral distal femur angle) to 0.993 (wedge-angle) and from 0.896 (joint line convergence angle) to 0.995 (mechanical tibiofemoral angle) of mediCAD®. The ICC of height of wedge-base was 0.979 with PreOPlan® and 0.969 with mediCAD®. Comparing PreOPlan® and mediCAD®, the ICC of the height of wedge-base of the observers was 0.966, 0.956 and 0.969, respectively.ConclusionsThe results show a high interrater reliability of digital planning software. Experience of the observer had no influence on results. Furthermore, a high interrater reliability and correlation of digital planning specific parameters was found. Surgeons need to master limb geometry measurements and osteotomy planning on digital radiographs as digital planning reports are used for intercolleagual correspondence, teaching purposes and as medicolegal documents. The digital planning software tested agrees with the actual demands and could be recommended for deformity analysis and planning of osteotomies.Level of evidenceDiagnostic studies, Level I.

Comminuted fractures of the proximal ulna—Preliminary results with an anatomically preshaped locking compression plate (LCP) system

INTRODUCTION The purpose of this investigation was to review the preliminary results and patients outcome following treatment with an anatomically preshaped LCP in patients with comminuted fractures of the proximal ulna. We hypothesized that this fixation system provides equal or superior results in fracture care when compared with other available plating devices, but results in better patients comfort due to its low-profile design. PATIENTS AND METHODS Between 2007 and 2009, 15 patients with comminuted fractures of the proximal ulna including three posterior Monteggia fractures were managed with the preshaped LCP olecranon plate. The patients were invited for clinical examination at a mean duration of 16 months, retrospectively. Validated patient-oriented assessment scores involving the Mayo Elbow Performance Index (MEPI) and the shortened Disability of the Arm, Shoulder and Hand (Quick-DASH) score, postoperative range of motion, objective muscle-strengths testing and patients satisfaction were evaluated. All patients had follow-up radiographs. RESULTS Fourteen patients were available for evaluation. The mean arc of elbow motion was 129°. The mean MEPI was 97 with good results in two patients and excellent results in 12 patients. The mean Quick-DASH was 13. Thirteen of fourteen patients documented satisfaction with their elbow outcome. There was one patient with symptomatic hardware and one patient complained about deficit of motion. In four patients the hardware was removed including two patients with elective removal. Fourteen fractures healed with ulnohumeral congruity after a mean time to union of 11 weeks. One fracture non-union occurred without mechanical failure or loss of reduction. CONCLUSION Anatomically preshaped LCP olecranon plating is an effective fixation method for comminuted fractures of the proximal ulna allowing reliable stability for early elbow motion. The functional results are comparable with formerly described plating systems. A low rate of symptomatic hardware removal suggests better patients compatibility.

Crucial Role of Vitamin D in the Musculoskeletal System

Vitamin D is well known to exert multiple functions in bone biology, autoimmune diseases, cell growth, inflammation or neuromuscular and other immune functions. It is a fat-soluble vitamin present in many foods. It can be endogenously produced by ultraviolet rays from sunlight when the skin is exposed to initiate vitamin D synthesis. However, since vitamin D is biologically inert when obtained from sun exposure or diet, it must first be activated in human beings before functioning. The kidney and the liver play here a crucial role by hydroxylation of vitamin D to 25-hydroxyvitamin D in the liver and to 1,25-dihydroxyvitamin D in the kidney. In the past decades, it has been proven that vitamin D deficiency is involved in many diseases. Due to vitamin D’s central role in the musculoskeletal system and consequently the strong negative impact on bone health in cases of vitamin D deficiency, our aim was to underline its importance in bone physiology by summarizing recent findings on the correlation of vitamin D status and rickets, osteomalacia, osteopenia, primary and secondary osteoporosis as well as sarcopenia and musculoskeletal pain. While these diseases all positively correlate with a vitamin D deficiency, there is a great controversy regarding the appropriate vitamin D supplementation as both positive and negative effects on bone mineral density, musculoskeletal pain and incidence of falls are reported.

Treatment of Complex Acetabular Fractures Through a Modified Extended Iliofemoral Approach

Objectives To assess the rate of anatomic reconstructions as well as approach-related morbidity and complications in the treatment of complex acetabular fractures through a modified extended iliofemoral approach. Design Prospective clinical study. Setting Level I trauma center, University Hospital. Patients Inclusion criteria were as follows: (a) associated acetabular fracture or transverse fracture with comminuted roof area stated as not sufficiently reconstructable through a single approach, and (b) age between sixteen and sixty-five years. A total of forty-nine patients with fifty complex acetabular fractures could be included out of the series of ninety-six acetabular fractures treated operatively from August 1992 to February 1996. Open reduction and internal fixation of complex acetabular fractures through the modified extended iliofemoral approach were performed. Results In 80 percent of the fifty fractures the reduction was anatomic with a remaining displacement of less than or equal to one millimeter, in eight cases there was a persistent displacement of two millimeters, and two fractures had a poor result with a three-millimeter displacement. Complications included 8 percent loss of reduction, 13 percent heterotopic ossification grade 3, and 4 percent avascular femoral head necrosis. At the two-year follow-up there were 74 percent good or excellent radiographic and clinical results. Two patients had already been reoperated with total hip replacement, and the two patients with femoral head necrosis are currently scheduled for arthroplasty. Conclusions The modified extended iliofemoral approach proved to be appropriate to achieve anatomic reduction in complex acetabular fractures. The high rate of approach-related morbidity has to be considered carefully and may lead to a decreased incidence of extended approaches.