[Surgical hip dislocation : Current status in the treatment of femoral acetabular impingement]

INTRODUCTION

Surgical hip dislocation (SHD) in the therapy of femoral acetabular impingement (FAI) has been mostly replaced by minimally invasive techniques. Nevertheless, in the circumstances of complex FAI types and combined impingement located in inaccessible areas of the hip, SHD is an option to reach those deformities. The advantage of the complete overview of the hip joint enables the circumferential therapy of bony deformity, but at the expense of higher invasivity. In the literature there is still a lack of mid to long-term studies of SHD to determine the overall treatment outcome. Therefore, the aim of this study is to evaluate the treatment outcome, risks and complications of SHD in FAI therapy within a mid-term follow-up.

METHODS

A total of 43 patients (mean follow-up 54 months.) with combined ventral and dorsal impingement who undertook SHD were retrospectively reviewed. Outcome parameters were range of motion (ROM), the Harris hip score (HHS), the hip outcome score (HOS), the activity level, pain, complications, conversion to total hip arthroplasty (THA) and patient specific surveys. Additionally, radiographs and the influence of preoperative osteoarthrosis were evaluated.

RESULTS

We were able to demonstrate a significant increase of ROM, HHS (69 → 80 Pkt.; p < 0.05), hip function and a decrease in pain level. The return to sport rate was 81%, but in most cases the patients had to reduce the intensity or change to a low impact sport activity. Overall, 75% were satisfied with the treatment outcome. The alpha angle improved from 70 to 45° (p < 0.05). Patients with preoperatively advanced hip osteoarthrosis showed no decent improvement of hip function. Conversion to THA was necessary in 36% of cases. The complication rate was about 13%.

CONCLUSION

SHD is successful in the treatment of combined ventral and dorsal impingement within a mid-term follow-up. The improvement of hip function and the reduction of pain symptoms is possible. In case of a manifest arthrosis an indication for SHD is no longer reasonable.

Mid-Term Survival of Total Knee Arthroplasty in Patients with Posttraumatic Osteoarthritis

PURPOSE OF THE STUDY There is limited evidence on survival and complication rates in patients after total knee arthroplasty for posttraumatic osteoarthritis. The failure mechanisms leading to revision remain an issue of constant debate. The purpose of this study was to analyze the mid-term survival of primary total knee arthroplasties as well as to evaluate complications and failure mechanisms in patients with posttraumatic knee osteoarthritis. MATERIAL AND METHODS This retrospective study included 79 patients with an average age of 59 years at the time of primary total knee arthroplasty. A functional and radiographic assessment was obtained during outpatient clinical follow-up at 3 and 12 months postoperatively and yearly intervals after that. Survival rates were calculated using Kaplan-Meier analyses. The mean postoperative follow-up was 69 months. RESULTS At 69 month the revision-free survival rate was 88.6%. In nine cases (11.4%) a revision procedure was performed. The leading cause of revision was a periprosthetic infection (n = 6, 66.6%). An age of fewer than 55 years at the time of total knee arthroplasty had a significant influence on implant survival (p = 0.018) with superior survival in favor of the older patient population. At most recent follow-up, a mean Knee Society Score of 82 points and an average Function Score of 77 points were observed. CONCLUSIONS Periprosthetic joint infection is the primary failure mechanism leading to a revision in patients with total knee arthroplasty for posttraumatic osteoarthritis. Apart from the increased infection rate, total knee arthroplasties in patients with posttraumatic osteoarthritis revealed results that were comparable to patients with primary osteoarthritis. Key words:posttraumatic knee osteoarthritis, total knee replacement, survival, complications, revision, outcome.

X-ray scattering experiments with high-flux X-ray source coupled rapid mixing microchannel device and their potential for high-flux neutron scattering investigations

Small-angle X-ray scattering provides global, shape-sensitive structural information about macromolecules in solution. Its extension to time dimension in the form of time-resolved SAXS investigations and combination with other time-resolved biophysical methods contributes immensely to the study of protein dynamics. TR-SAXS can also provide unique information about the global structures of transient intermediates during protein dynamics. An experimental set-up with low protein consumption is essential for an extensive use of TR-SAXS experiments on protein dynamics. In this direction, a newly developed 20-microchannel microfluidic continuous-flow mixer was combined with SAXS. With this set-up, we demonstrate ubiquitin unfolding dynamics after rapid mixing with the chaotropic agent Guanidinium-HCl within milliseconds using only ∼ 40 nanoliters of the protein sample per scattering image. It is suggested that, in the future, this new TR-SAXS platform will help to increase the use of time-resolved small-angle X-ray scattering, wide-angle X-ray scattering and neutron scattering experiments for studying protein dynamics in the early millisecond regime. The potential research field for this set-up includes protein folding, protein misfolding, aggregation in amyloidogenic diseases, function of intrinsically disordered proteins and various protein-ligand interactions.

Factors that influence high tibial osteotomy results in patients with medial gonarthritis: a score to predict the results

OBJECTIVE

High tibial osteotomy (HTO) for the treatment of unicompartmental knee osteoarthritis in the presence of axial malalignment is recognized as an effective treatment for young and active patients. The aim of this study was to identify HTO prognostic factors.

METHODS

A total of 94 patients who had undergone HTO with additive arthroscopy were scored using the "knee injury and osteoarthritis outcome score" (KOOS). A KOOS of less than 114 points was judged as a poor outcome.

RESULTS

A total of 84 patients were available for follow-up after a time-interval of 45.9+/-7.6 (range 34-60) months. The KOOS increased from 46.1+/-11.1 to 120.3+/-40.8. The preoperative varus angle in all patients was 7.5 degrees +/-1.9 (range 5-14 degrees ). In follow-up the patients had a mean valgus angle of 3.7 degrees +/-2.5. Twenty-three patients (27.4%) had suffered a loss of correction (0.8 degrees , range 0-2 degrees ). A loss of correction correlated with a minor result in tendency. A total of 25 patients (29.8%) had a poor KOOS. Factors associated with a poor HTO outcome were a patient history of more than 24 months, a preoperative KOOS>50 points, obesity, and smoking. However, the results were also influenced by radiological findings, such as medial tibial exophyte, a medial joint space width of less than 5mm, and intraarticular damage, such as a degree IV cartilage defect of the tibia. Gender was also a minor prognostic factor. Patient's age and the event of prior surgery did not influence the outcome.

CONCLUSION

This study identified relevant factors that significantly influenced HTO results. It was possible to create a "predictive score" for HTO patients. Patients with more than 4 of the poor prognostic factors should chose primary arthroplasty.

Comparison of corneal versus through-the-lid A-scan ultrasound biometry

BACKGROUND

Accurate ultrasonography data on axial ocular dimensions in infants and toddlers are essential for understanding ocular development. Conventional methods using corneal contact with topical anesthesia but without sedation are not feasible for most of these patients. We evaluate an alternative method which places the probe on the closed eyelid.

METHODS

We compared A-scan ultrasound biometry measurements taken with the probe directly on the cornea with those with the probe on the closed eyelid on the right eye of 35 young adult subjects.

RESULTS

There was no significant difference between methods for mean anterior chamber depth (corneal = 3.83 mm, lid = 3.87 mm, p = 0.13, paired t-test). The mean lens thickness (corneal = 3.63 mm, lid = 3.75 mm, p = 0.0001, paired t-test) and mean vitreous chamber depth (corneal = 17.50 mm, lid = 17.68 mm, p = 0.0440, paired t-test) were significantly different.

CONCLUSION

Ultrasonography through the closed eyelid appears to be a viable method with acceptable validity compared with corneal ultrasound. Poorer agreement for lens thickness and vitreous chamber depth may be undesirable, but these data should be useful for planning future studies of infants and toddlers.