Introduction

The purpose of this study was to evaluate the functional and radiographical mid-term follow-up results of a second generation metal-on-metal cementless total hip arthroplasty for the treatment of osteonecrosis of the femoral head in patients younger than 50 years.

Ponseti method has become the most common and validated initial non-operative and/or minimally invasive treatment modality of idiopathic clubfoot regardless of the severity of the deformity worldwide. Despite hundreds of publications in the literature favoring Ponseti method, the data about secondary procedures performed in the follow-up period of clubfoot and their incidence remains sparse and given as small details in the articles. The objective of this study was to analyse our incidence of secondary procedures performed in the midterm followup period of idiopathic clubfoot patients treated with Ponseti method and review of the relevant literature. For this purpose 86 feet of 60 patients with idiopathic clubfoot who were treated with original Ponseti method were enrolled in this retrospective case control study. Unilateral ankle foot orthosis (AFO) was used rather than standart bar-connected foot abduction orthosis varying from 12 months to 25 months in the follow-up period and 74 of 86 (86%) feet required percutaneous achilles tenotomy. The average age of initial cast treatment was 12.64 days (range 1 to 102 days). The mean follow-up time was 71 months (range 19 to 153 months). Thirty seven feet of 24 patients recieved secondary procedures (43%) consisting of; supramalleolary derotational osteotomy (SMDO) (1 patient/2 feet), complete subtalar release (3 patients/5 feet), medial opening lateral closing osteotomy (double osteotomy) (2 patients/3 feet), double osteotomy with transfer of tibialis anterior tendon (TTAT) (2 patients/3 feet), partial subtalar release (PSTR) (3 patients/5 feet), PSTR with SDO (1 patient/1 foot), posterior release (PR) with repeated achillotomy (1 patient/2 feet), TTAT (6 patients/10 feet), TTAT with PR (2 patients/2 feet), TTAT with Vulpius procedure (1 patient/1 foot) and TTAT with SMDO (2 patients/3 feet) respectively. The amount of percutaneous achilles tenotomy (86%) in our study correlated with the literature which ranged from 80 to 90 %. The transfer of tibialis anterior tendon continued to be the most performed secondary procedure both in our study (51%) and in the literature, but the amount of total secondary procedures in our study (43%) was determined to be higher than the literature data varying from 7 to 27 percent which may be due to unilateral AFO application after Ponseti method for idiopathic clubfoot deformity in our study

Background. Hip resurfacing has resurged in the last decade due to a renewed interest in metal on metal bearing. One of the proposed advantages is ease of revision of the femoral component. Short term functional results after femoral revision are similar to those after conventional total hip replacement. Survival and function after revision of the acetabular component only or of both components have not been reported. We aimed to assess hip function and implant survival after revision of the acetabular component for failed Birmingham hip resurfacing (BHR). Methods. The Oswestry Outcome Centre collected data prospectively on 5000 patients who underwent hip resurfacing between 1997 and 2002. Of these, 182 hips were revised: 42% had revision of the femoral component only, 8% revision of the acetabular component only, and 50% revision of both components. This study analyzed patients who had revision of the acetabular component, either in isolation or in combination with the femoral component. Results. In the isolated acetabular revision group the median Harris Hip Score was 74 at a mean of 4.5 years post-revision. In the both components revision group the median Harris hip score was 85 at a mean of 4 years. There was no significant difference in function between the groups. Kaplan-Meier survivor ship analysis after revision showed an average survival of 91% at 10 years. There was a significant difference between survival of isolated acetabular revision (75%) and both component revision (96%). Conclusions. Revision total hip replacement subsequent to failure of hip resurfacing has good outcome and good midterm survival. Isolated acetabular revision and revision of both components had similar function but survival was significantly worse in the isolated acetabular revision group

Summary Statement. To evaluate carbon-fiber-reinforced PEEK as alternative biomaterial for total disc arthroplasty a closed loop between biotribology (in vitro), application of sterile particle suspensions in the epidural space of rabbits and biological response in vivo was established. Introduction. To prevent adjacent level degeneration in the cervical spine, total disc arthroplasty (TDA-C) remains an interesting surgical procedure for degenerative disc disease. Short- or midterm complications are migration, impaired post-operative neurological assessment due to artefacts in x-ray and MRI diagnosis and substantial rates of heterotopic ossification. The idea was to create a TDA-C design based on a polymer-on-polymer articulation to overcome these limitations of the clinically established metal-on-polyethylene designs. The objective of our study was to characterise the biotribological behaviour of an experimental cervical disc replacement made out of carbon-fiber-reinforced (CFR) PEEK and evaluate the biological response of particulate wear debris in the epidural space in vivo. Materials & Methods. In vitro wear simulation acc. to ISO 18192-1 was performed for 10 million cycles on a clinically established TDA-C device (Aesculap, Tuttlingen) made of cobalt-chromium-on-polyethylene in a direct comparison to an experimental disc prototype made of CFR-PEEK. An estimation of particle size and morphology was done acc. to Affatato et al. [5] and sterile suspensions of comparable particles (size 90% < 1 µm) in phospate buffered saline (PBS) were produced [6] for the application in the epidural space of 36 white new zealand rabbits. The particle concentration was 1 mg/ml with a volume of 0.2 ml injected percutaneously using fluoroscopic guidance and the inflammatory response was assessed 3 and 6 months post-operatively in a direct comparison between the groups PBS (control), UHMWPE and CFR-PEEK. Results. The gravimetric wear rate was for the cobalt-chromium-on-polyethylene TDA-C device as a clinical reference 1.0 ± 0.1 mg/ million cycles, compared to 0.02 ± 0.02 mg/ million cycles for the experimental CFR-PEEK articulation (p < 0.001), whereas the cumulative amount of wear of the CFR-PEEK TDA-C prototypes (0.5 ± 0.23 mg/ million cycles) was decreased by an order of a magnitude compared to cobalt-chromium-on-polyethylene (12.1 ± 1.46 mg/ million cycles) (p < 0.001). For CFR-PEEK and UHMWPE most of the particles were observed in a submicron size range and the morphology was comparable. Histopathological examination demonstrated wear debris in the vertebral canal of injection sites surrounded by inflammatory cells. The inflammation was limited to the epidural space around the particles and polymer particles were associated by a low grade foreign body reaction comprising macrophages and multi-nucleated giant cells. CFR-PEEK particulate wear debris showed at least similar histopathological reactions than UHMWPE in the cervical epidural space. Conclusion. A closed loop between biotribology (in vitro), application of sterile particle suspensions in the epidural space of rabbits and biological response in vivo was established to evaluate carbon-fiber-reinforced PEEK as alternative biomaterial for total disc arthroplasty