The Halofixator for the Treatment of Unstable Fractures of the Upper Cervical Spine - Our Own Experience and Narrative Review. / Der Halofixateur zur Therapie von instabilen Frakturen der oberen Halswirbelsäule ­ eigene Erfahrungen und narratives Review.

INTRODUCTION: In the treatment of upper cervical spine injuries, the semiconservative procedure of the halofixator is now of only secondary importance. Older studies from the 2000 s showed unsatisfactory rates of consolidation as well as high rates of complications. However, due to current data on therapy effectiveness, the literature is inconsistent. The aim of this work is to compare our own experiences and results of treatment with the current literature and to help to clarify the role of the halofixator. MATERIAL AND METHODS: In a monocentric retrospective cohort study, patients with unstable injuries of the axial cervical spine who were to be treated in the halofixator were investigated. Individual variables (sex, age, concomitant diseases, Charlson Comorbidity Index) and treatment characteristics (duration of treatment, consolidation status, complications) were recorded using the electronic medical record. Injuries were classified based on CT data at the time of the accident and at the end of treatment, using common classification systems, and assessed with respect to the rate of consolidation. Possible factors influencing bony consolidation as well as complications were statistically analysed. RESULTS: A total of 54 patients met the inclusion criteria. The median duration of treatment was 83 days. The most common injuries were isolated atlas fracture type III (7; 13%) and isolated dens fracture type III (24; 44%). Bony consolidation was demonstrated in 34 cases (63%) and tight pseudarthrosis in 13 cases (24%). Secondary surgical stabilisation was performed in 6 cases (11%). Isolated type III atlas fractures and type III dens fractures had very high consolidation rates of 86% and 92%, respectively. In the subgroups of patients older than 65 years or with a CCI ≥ 4, unstable pseudarthroses were found more frequently. Complications included pin infection (6%), pin dislocation (9%), and pressure ulceration from the halo vest (6%). Cardiopulmonary complications did not occur. No patient died. DISCUSSION: Good rates of bony consolidation were seen for atlas fractures type III as well as dens fractures type III, which correlate with data in the literature. Dens fractures type II (isolated and combined) and atlas fractures type III in combination with dens fractures showed a worse radiological outcome, which is also unsatisfactory compared to the literature. The rates for procedure-specific complications were relatively low. In particular, work from recent years has demonstrated very good rates for bony consolidation and low complication rates for the treatment of atlas and/or dens fractures with the halofixator, which are confirmed by our results. In contrast, however, a significantly higher cardiac/respiratory complication rate has been reported than occurred in our own patient population.

Histopathological Analysis of the Degree of Tendinosis in Failed Anterior Cruciate Ligament Grafts. / Histopathologische Analyse des Tendinosegrades nach Transplantatversagen vorderer Kreuzbandplastiken.

INTRODUCTION: After reconstruction of the anterior cruciate ligament, the modification processes in the transplanted tendon tissue directly influence the biomechanical properties of the knee. The histopathological alterations in failed grafts have hardly been studied. OBJECTIVE: Our study focused on examining the presence and extent of tendinosis (low or high grade) in the tendon tissue of failed anterior cruciate ligament reconstructions. We considered its relationship to the type of transplant, the symptoms, the arthroscopic appearance, the mode of trauma, and the timing of the failure. MATERIALS AND METHODS: The tendon tissue of failed anterior cruciate ligament reconstructions in 30 patients was gathered during revision surgery and its histopathology was analysed for the occurrence of structural alterations. The classification of the tendinosis as low or high grade was semiquantitative based on five qualities. We used a standardised questionnaire to collect patient data and we used the Marburg Arthroscopy Score for the intraoperative evaluation of the graft. RESULTS: We found histological vitality and, except for two samples, structural alterations consistent with tendinosis, predominantly high grade, in all failed anterior cruciate ligament grafts. No direct link could be proved between the degree of tendinosis and the type of graft used, the symptoms (except for instability) or the timing of the graft failure, the mode of trauma, or the arthroscopic appearance of the failed plasty. However, the accumulation of high-grade tendinosis in patients with hamstring tendons, subjective instability, and graft failure between 1 to 5 years postoperatively was noteworthy. CONCLUSION: Structural alterations consistent with tendinosis could be detected, with different expressions, in the vital tendon tissue of anterior cruciate ligament reconstructions. This indicates that the graft is subject to repetitive microtrauma. However, it is still unclear how tendinosis influences the failure of anterior cruciate ligament reconstructions.

Radiation- and reference base-free navigation procedure for placement of instruments and implants: application to retrograde drilling of osteochondral lesions of the knee joint.

OBJECTIVE: A novel, radiation- and reference base-free procedure for placement of navigated instruments and implants was developed and its practicability and precision in retrograde drillings evaluated in an experimental setting. MATERIALS AND METHODS: Two different guidance techniques were used: One experimental group was operated on using the radiation- and reference base-free navigation technique (Fluoro Free), and the control group was operated on using standard fluoroscopy for guidance. For each group, 12 core decompressions were simulated by retrograde drillings in different artificial femurs following arthroscopic determination of the osteochondral lesions. The final guide-wire position was evaluated by postoperative CT analysis using vector calculation. RESULTS: High precision was achieved in both groups, but operating time was significantly reduced in the navigated group as compared to the control group. This was due to a 100% first-pass accuracy of drilling in the navigated group; in the control group a mean of 2.5 correction maneuvers per drilling were necessary. Additionally, the procedure was free of radiation in the navigated group, whereas 17.2 seconds of radiation exposure time were measured in the fluoroscopy-guided group. CONCLUSION: The developed Fluoro Free procedure is a promising and simplified approach to navigating different instruments as well as implants in relation to visually or tactilely placed pointers or objects without the need for radiation exposure or invasive fixation of a dynamic reference base in the bone.