Sabine Ochman

Long-term results after primary microsurgical repair of ulnar and median nerve injuries. A comparison of common score systems.

OBJECTIVE The aim of this retrospective study was to analyze the long-term results of primary repair of median and ulnar nerve lesions. Clinical influence factors for nerve reconstruction were investigated. Furthermore, current score systems were inquired and evaluated on their effectiveness to illustrate the success of repair. PATIENTS AND METHOD Sixty-five patients with 71 lesions of the median and ulnar nerve were assessed on average 8.2 years after reconstruction. The results were classified according to the DASH (disability of arm, shoulder, and hand) Score, the Rosens hand protocol and the Highet Scale. RESULTS On average the patients regained 70% of their original hand function (evaluated by Rosen Score: median nerve 2.2/for ulnar nerve 1.92 out of 3.0). Although we noticed inferior motor recovery in ulnar nerve lesions, no significant differences between the overall results of both nerves were observed. Neither accompanying artery and flexor tendon injuries nor the suture technique influenced the recovery. The age of the patient was confirmed as an important influence factor. The results of the DASH Score, Rosen Score and Highet Score correlated significantly. CONCLUSION For a sufficient outcome measurement we underline the importance of evaluation of patients estimation of their impact on their activities of daily living. For this a combination of the functional Rosen Score and the DASH Score is suggested.

Comparison Between Locking and Non-Locking Plates for Fixation of Metacarpal Fractures in an Animal Model

PURPOSE The use of locking plates increases the primary load to failure, thereby reducing the rate of implant-related failure. The good clinical and biomechanical results of locking plates in long bones might be applicable to treatment of metacarpal fractures. The purpose of this study was to determine strength and stiffness of locking plates in a metacarpal fracture model with mono- and bicortical screw fixation in comparison to non-locking plate mono- and bicortical screw fixation, with both types of plates placed at the dorsal side of the bone. METHODS Fresh second metacarpals from domestic pigs (n=40) were randomized in 4 equal groups. Short, oblique, mid-shaft fractures were generated, using a standardized 3-point bending method. Fractures were plated with non-locking, titanium, 1-mm-thick monocortical (group 1, n=10) or bicortical (group 2, n =10) plates (Leibinger-Stryker; Stryker Corp, Freiburg, Germany). Newly designed locking titanium plates with the same width and thickness (Leibinger-Stryker) were used in the same manner for groups 3 (monocortical) and 4 (bicortical). The metacarpals were then tested to load to failure in a cantilever bending mode. RESULTS Bicortical, non-locking fixation (group 2, 359 +/- 90 N) had a higher load to failure than monocortical non-locking fixation (group 1, 250 +/- 56 N) in testing the maximum load to failure (p < .01). There was no significant difference in stiffness between group 1 (46 +/- 12 N/mm) and group 2 (56 +/- 21 N/mm). The difference in maximum load to failure between monocortical (group 3, 440 +/- 85N) and bicortical (group 4, 378 +/- 116 N) locking plate stabilization was not significant. Also, there was no significant difference in stiffness between monocortical (group 3, 83 +/- 35 N/mm) and bicortical locking plates (group 4, 70 +/- 31 N/mm). Comparing non-locking (group 1) and locking plates in a monocortical fixation technique (group 3) demonstrated significant differences in maximum load to failure (group 1, 250 +/- 56 N; group 3, 440 +/- 85 N) and stiffness (group 1, 46 +/- 12 N/mm; group 3, 83 +/- 35 N/mm). The stability of monocortical locking plates was stronger, although not statistically significant, than the non-locking bicortical plates (load to failure, 440 +/- 85 N vs 359 +/- 90 N; stiffness, 83 +/- 35 N/mm vs 56 +/- 21 N/mm). CONCLUSIONS The new generation of locking plates can be used to achieve a higher stability for fixation of metacarpal fractures. Monocortical, stable fixation can minimize flexor tendon interference and probably reduce bone and soft tissue trauma.

Retrograde nail for tibiotalocalcaneal arthrodesis as a limb salvage procedure for open distal tibia and talus fractures with severe bone loss.

The treatment of complex fractures of the distal tibia, ankle, and talus with soft tissue damage, bone loss, and nonreconstructable joints for which the optimal timing for reduction and fixation has been missed is challenging. In such cases primary arthrodesis might be a treatment option. We report a series of multi-injured patients with severe soft tissue damage and bone loss, who were treated with a retrograde tibiotalocalcaneal arthrodesis nail as a minimally invasive treatment option for limb salvage. After a median follow-up of 5.4 years, all patients returned to their former profession. The ankle and bone fusion was complete, with moderate functional results and quality of life. Calcaneotibial arthrodesis using a retrograde nail is a good treatment option for nonreconstructable fractures of the ankle joint with severe bone loss and poor soft tissue quality in selected patients with multiple injuries, in particular, those involving both lower extremities, as a salvage procedure.

Current concepts in the treatment of Anderson Type II odontoid fractures in the elderly in Germany, Austria and Switzerland

Although currently there are many different recommendations and strategies in the therapy of odontoid fractures in the elderly, there are still no generally accepted guidelines for a structured and standardised treatment. Moreover, the current opinion of spine surgeons regarding the optimal treatment of odontoid fractures Type II of the elderly is unknown. In order to have an objective insight into the diverging strategies for the management of Anderson Type II odontoid fractures and form a basis for future comparisons, this study investigated the current concepts and preferences of orthopaedic, neuro- and trauma surgeons. Spine surgeons from 34 medical schools and 8 hospitals in Germany, 4 university hospitals in Austria and 5 in Switzerland were invited to participate in an online survey using a 12-item 1-sided questionnaire. A total of 44 interviewees from 34 medical institutions participated in the survey, consisting of trauma (50%), orthopaedic (20.5%) and neurosurgeons (27.3%). Out of these, 70.5% treated 1-20 fractures per year; 63.6% favoured the anterior screw fixation as therapy for Type II odontoid fractures, the open posterior Magerl transarticular C1/C2 fusion, the posterior Harms C1/C2 fusion, and conservative immobilisation by cervical orthosis was preferred by 9.1% in each case. 59.1% preferred the anterior odontoid screw fixation as an appropriate treatment of Anderson Type II odontoid fractures in the elderly. 79.5% chose cervical orthosis for postsurgical treatment. Following operative treatment, nonunion rates were reported to be <10% and <20% by 40.9% and 70% of the surgeons, respectively. 56.8% reported changing from primary conservative to secondary operative treatment in <10% of cases. The most favoured technique in revision surgery of nonunions was the open posterior Magerl transarticular fusion technique, chosen by 38.6% of respondents. 18.2% preferred the posterior Harms C1/C2 fusion technique, 11.4% the percutaneous posterior Magerl technique and the anterior odontoid screw fixation in each case. This study discovered major variations in the treatment of Anderson Type II odontoid fractures in the elderly in terms of indication for conservative and operative treatment between several treatment centres in 3 European countries. Difficulty and complexity in formulating general guidelines based on multicenter studies is conceivable.

Biomechanical comparison of stability of tibiotalocalcaneal arthrodesis with two different intramedullary retrograde nails

BACKGROUND The aim of the study was to compare the initial construct stability of two retrograde intramedullary nail systems for tibiotalocalcaneal arthrodesis (TTCF) (A3, Small Bone Innovations; HAN, Synthes) in a biomechanical cadaver study. METHODS Nine pairs of human cadaver bones were instrumented with two different retrograde nail systems. One tibia from each pair was randomized to either rod. The bone mineral density was determined via tomography to ensure the characteristics in each pair of tibiae were similar. All tests were performed in load-control. Displacements and forces were acquired by the sensors of the machine at a rate of 64Hz. Specimens were tested in a stepwise progression starting with six times ±125N with a frequency of 1Hz for 250cycles each step was performed (1500cycles). The maximum load was then increased to ±250N for another 14 steps or until specimen failure occurred (up to 3500cycles). RESULTS Average bone mineral density was 67.4mgHA/ccm and did not differ significantly between groups (t-test, p=.28). Under cyclic loading, the range of motion (dorsiflexion/plantarflexion) at 250N was significantly lower for the HAN-group with 7.2±2.3mm compared to the A3-group with 11.8±2.9mm (t-test, p<0.01). Failure was registered for the HAN after 4571±1134cycles and after 2344±1195cycles for the A3 (t-test, p=.031). Bone mineral density significantly correlated with the number of cycles to failure in both groups (Spearman-Rho, r>.69, p<0.01). CONCLUSIONS The high specimen age and low bone density simulates an osteoporotic bone situation. The HAN with only lateral distal bend but two calcaneal locking screws showed higher stability (higher number of cycles to failure and lower motion such as dorsiflexion/plantarflexion during cyclic loading) than the A3 with additional distal dorsal bend but only one calcaneal locking screw. Both constructs showed sufficient stability compared with earlier data from a similar test model. CLINICAL RELEVANCE The data suggest that both implants allow for sufficient primary stability for TTCF in osteoporotic and consequently also in non-osteoporotic bone. LEVEL OF EVIDENCE Not applicable, experimental basic science study.

Local application of VEGF compensates callus deficiency after acute soft tissue trauma--results using a limb-shortening distraction procedure in rabbit tibia.

Acute soft tissue trauma influences callus formation and fracture healing. Several studies showed a relationship between angiogenesis and bone formation during distraction osteogenesis. The purpose of this study was to investigate the influence of controlled release of vascular endothelial growth factor (VEGF) on callus formation in a limb‐shortening distraction procedure after acute compartment syndrome. Acute soft tissue trauma with critical increased compartment pressure was generated in 22 rabbits, and the limb was shortened simulating fracture site debridement. In the test group (n = 11), a VEGF‐coated collagen matrix was locally applied around the fracture, while no collagen was applied in the control group (n = 11). Following 10 days in limb shortening, a gradual distraction of 0.5 mm/12 h was performed using an external fixation device and followed up for 40 days. Osseous consolidation occurred in all animals. Average callus diameter (1.54 ± 0.8 vs. 1.27 ± 0.14 mm) and torsional strength (72% vs. 46% of normal) were significantly higher in the test versus the control group. Blood vessel formation increased with a significantly higher number of vessels (6.3 vs. 3.81/mm2) and larger cross‐sectional area (>40 µm, 90.5% vs. 86%) in the test versus control group. The results showed that locally applied VEGF stimulates fracture healing after acute soft tissue trauma and might be an option for fracture treatment in cases with severe soft tissue damage.

Cooperative effects in differentiation and proliferation between PDGF-BB and matrix derived synthetic peptides in human osteoblasts

BackgroundEnhancing osteogenic capabilities of bone matrix for the treatment of fractures and segmental defects using growth factors is an active area of research. Recently, synthetic peptides like AC- 100, TP508 or p-15 corresponding to biologically active sequences of matrix proteins have been proven to stimulate bone formation. The platelet-derived growth factor (PDGF) BB has been identified as an important paracrine factor in early bone healing. We hypothesized that the combined use of PDGF-BB with synthetic peptides could result in an increase in proliferation and calcification of osteoblast-like cells.MethodsOsteoblast-like cell cultures were treated with PDGF and synthetic peptides, singly and as combinations, and compared to non-treated control cell cultures. The cultures were evaluated at days 2, 5, and 10 in terms of cell proliferation, calcification and gene expression of alkaline phosphate, collagen I and osteocalcin.ResultsExperimental findings revealed that the addition of PDGF, p-15 and TP508 and combinations of PDGF/AC-100, PDGF/p-15 and PDGF/TP508 resulted in an increase in proliferating osteoblasts, especially in the first 5 days of cultivation. Proliferation did not significantly differ between single factors and factor combinations (p > 0.05). The onset of calcification in osteoblasts occurred earlier and was more distinct compared to the corresponding control or PDGF stimulation alone. Significant difference was found for the combined use of PDGF/p-15 and PDGF/AC-100 (p < 0.05).ConclusionsOur findings indicate that PDGF exhibits cooperative effects with synthetic peptides in differentiation and proliferation. These cooperative effects cause a significant early calcification of osteoblast-like cells (p < 0.05). We suggest the combination of synthetic peptides and PDGF as a potential clinical approach for accelerating bone healing or coating osteosynthesis materials.

Size matters: The influence of the posterior fragment on patient outcomes in trimalleolar ankle fractures

INTRODUCTION Ankle fractures are increasing in incidence. The more complicated the lesion is, the higher the risk of developing posttraumatic arthrosis. Severe posttraumatic arthrosis results in a reduced quality of life. Therefore, the treatment of a trimalleolar fractures is crucial. However, the treatment guidelines for posterior malleolar fractures (PMF) are still based on recommendations from 1940. Only a few retrospective studies have been conducted, which analysed patient outcomes based on lateral X-rays of the ankle. The purpose of this retrospective analysis was to survey patient outcomes in relation to the size of the PMF on the basis of CT-scans. METHODS We retrospectively examined 42 patients with trimalleolar fractures with an average follow-up of 2.5 years. Twenty-four patients (57%) received a CT scan of the ankle joint. The radiologic images were analysed for the size of the PMF and the involvement of the joint surface using lateral X-rays and available CT images. We examined all 42 patients clinically and radiologically, and estimated the grade of arthrosis of the ankle in accordance with the Bargon Score and assigned AOFAS Scores for each patient. We divided our patients into different groups according to the size of their PMF and evaluated patient outcomes in accordance with the compiled data first on the basis of X-ray data and then on the basis of CT data. RESULTS Comparing the measurement results by two different radiologic methods revealed that CT results in a more precise determination of PMF size in contrast to lateral X-rays, by which measurements were generally overrated. The statistical evaluation of our data demonstrated that patients with an osteosynthesis of the PMF and a PMF size of >25% showed signs of posttraumatic arthrosis but had better outcomes in accordance to the AOFAS score. All results were not significant. CONCLUSION An exact evaluation of CT images of posterior malleolar fractures in patients with trimalleolar ankle fractures is crucial for the decision to perform an osteosynthesis of the PMF and, therefore, an analysis of patient outcomes. The results of previous studies should be evaluated cautiously due to missing CT data. To date, this is the largest retrospective patient series of patient outcomes based on CT data.

Experimental Fracture Model versus Osteotomy Model in Metacarpal Bone Plate Fixation

Introduction. Osteotomy or fracture models can be used to evaluate mechanical properties of fixation techniques of the hand skeleton in vitro. Although many studies make use of osteotomy models, fracture models simulate the clinical situation more realistically. This study investigates monocortical and bicortical plate fixation on metacarpal bones considering both aforementioned models to decide which method is best suited to test fixation techniques. Methods. Porcine metacarpal bones (n = 40) were randomized into 4 groups. In groups I and II bones were fractured with a modified 3-point bending test. The intact bones represented a further control group to which the other groups after fixation were compared. In groups III and IV a standard osteotomy was carried out. Bones were fixated with plates monocortically (group I, III) and bicortically (group II, IV) and tested for failure. Results. Bones fractured at a mean maximum load of 482.8 N ± 104.8 N with a relative standard deviation (RSD) of 21.7%, mean stiffness was 122.3 ± 35 N/mm. In the fracture model, there was a significant difference (P = 0.01) for maximum load of monocortically and bicortically fixed bones in contrast to the osteotomy model (P = 0.9). Discussion. In the fracture model, because one can use the same bone for both measurements in the intact state and the bone-plate construct states, the impact of inter-individual differences is reduced. In contrast to the osteotomy model there are differences between monocortical and bicortical fixations in the fracture model. Thus simulation of the in vivo situation is better and seems to be suitable for the evaluation of mechanical properties of fixation techniques on metacarpals.

Biomechanical Analysis of the Efficacy of Locking Plates during Cyclic Loading in Metacarpal Fractures

Purpose. To analyse the biomechanical characteristics of locking plates under cyclic loading compared to a nonlocking plate in a diaphyseal metacarpal fracture. Methods. Oblique diaphyseal shaft fractures in porcine metacarpal bones were created in a biomechanical fracture model. An anatomical reduction and stabilization with a nonlocking and a comparable locking plate in mono- or bicortical screw fixation followed. Under cyclic loading, the displacement, and in subsequent load-to-failure tests, the maximum load and stiffness were measured. Results. For the monocortical screw fixation of the locking plate, a similar displacement, maximum load, and stiffness could be demonstrated compared to the bicortical screw fixation of the nonlocking plate. Conclusions. Locking plates in monocortical configuration may function as a useful alternative to the currently common treatment with bicortical fixations. Thereby, irritation of the flexor tendons would be avoided without compromising the stability, thus enabling the necessary early functional rehabilitation.