Prognostication in Developmental Dysplasia of the Hip Using the Ossific Nucleus Center Edge Angle.

BACKGROUND: The aim of this paper was to determine the prognostic potential of the ossific nucleus center edge angle (ONCEA) in patients below 5 years of age treated for developmental dysplasia of the hip (DDH) to predict final outcome and the need for a secondary procedure. METHODS: The interobserver and intraobserver reliability was calculated using the intraclass correlation coefficient for measurement of the ONCEA. The ONCEA was divided a priori into 3 groups: group A≥10 degrees, group B -9 to 9 degrees, and group C ≤-10 degrees. Final outcome was measured using the McKay score and Severin classification. The presence of osteonecrosis was recorded at final follow-up. RESULTS: One hundred one patients with 133 dislocated hips underwent closed or open reduction for DDH. Mean age at presentation was 19 months with a mean age at final follow-up of 12.4 years. A significant difference was shown in a comparison of the 3 ONCEA groups using the McKay score, Severin classification, and need for a secondary procedure. Eighty seven of the 101 patients underwent ONCEA reliability measurements. The ONCEA was shown to have a mean intrarater reliability of 0.89, and a mean interrater reliability of 0.77. CONCLUSIONS: The ONCEA is a reliable measurement in predicting medium-term outcome of the hip post reduction in children under the age of 5 years with DDH and might be useful as a predictor for a secondary procedure before the age of 5 years. LEVEL OF EVIDENCE: Level III-prognostic case control study. CLINICAL RELEVANCE: This case control study shows the importance of measuring the ONCEA within 6 months of removing the final cast after reduction of a dislocated hip and its implications for further management and outcome.

A prospective randomized clinical trial comparing tibial baseplate fixation with or without screws in total knee arthroplasty: a radiographic evaluation.

In a randomized prospective study, we compared the use of tibial screws with screwless tibial baseplate fixation in uncemented total knee arthroplasty and report the results of 154 prostheses at a mean follow-up of 5 years. Patients were mobilized within 24 hours and continued with partial weight-bearing for up to 6 weeks postoperatively. There were no significant differences in radiologic results and revision rates. Radiographic outcomes do not seem to be influenced by the use of screws in tibial baseplate fixation of this prosthesis. The prosthesis studied has a large tibial keel and 4 adjunctive pegs that seem to provide adequate stability and allow bony ingrowth to take place. Longer follow-up will determine whether in this implant design, the use of tibial screws for cementless tibial baseplate fixation can be justified.

The 2007 Otto Aufranc Award. Ceramic-on-metal hip arthroplasties: a comparative in vitro and in vivo study.

The performance of novel ceramic-on-metal bearing couples has been compared with metal-on-metal and ceramic-on-ceramic bearing couples in laboratory and short-term clinical studies. Laboratory studies compared ceramic-on-metal with metal-on-metal and ceramic-on-ceramic bearings with diameters of 28 and 36 mm under standard conditions and under adverse conditions with head loading on the rim of the cup. Clinical studies compared metal ion levels in ceramic-on-metal with metal-on-metal, ceramic-on-ceramic, and ceramic-on-polyethylene bearings in a randomized prospective study. In the laboratory studies, friction, wear, and ion levels were lower in ceramic-on-metal bearings compared with metal-on-metal, with results similar to ceramic-on-ceramic couples. Under adverse conditions and rim loading, all bearings showed increased wear with lower wear and absence of stripe wear in ceramic-on-metal compared with metal-on-metal bearings. Short-term studies in 31 patients at 6 months revealed lower metal ion levels (cobalt and chromium) in those with ceramic-on-metal compared with metal-on-metal bearings.