Patellar instability is a complex, multi-factorial disorder. Radiological assessment is regarded as an important part of the management of this population. The purpose of this study was to determine the intra- and inter-rater reliability of common radiological measurements used to evaluate patellar instability. One hundred and fifty x-rays from 51 individuals were reviewed by five reviewers: two orthopaedic trainees, a radiological trainee, a consultant radiologist and an orthopaedic physiotherapist. Radiological measurements assessed included patellar shape, sulcus angle, congruence angle, lateral patellofemoral angle (LPA), lateral patellar displacement (LPD), lateral displacement measurement (LDM), boss height, and patellar height ratios (Caton-Deschamps, Blackburne-Peel, Insall-Salvati). All assessors were provided with a summary document outlining the method of assessing each measurement. Bland-Altman analyses were adopted to assess intra- and inter-rater reliability.Background
Methods
Hard-on-hard bearing surface have been accepted as a valuable alternative for young and active patients needing a hip replacement because these combinations are resistant to wear. Initial development of alumina-on-alumina bearings faced complications such as fractures, and socket loosening. But, with the increasing number of prostheses implanted, noise occurrence appeared as a new complication. The primary aim of the present survey was to quantify the prevalence of having noise in a population receiving alumina-on-alumina hip arthroplasty. Two hundred and eighty-four ceramic-on-ceramic hips were performed in 238 patients (126 males and 112 females) from January 2003 to December 2004. The average age at the index operation was 52.4 ± 13.4 years (range, 13 to 74 years). We used the same type of prosthesis for all patients manufactured in all cases by Ceraver-Osteal®. Clearance between femoral and insert was between 20 and 50 microns in order to achieve minimal wear. The survey was conducted by an independent surgeon who did not participated in patients care during the last 6 months of 2007. He interviewed the patients by phone with a standardized questionnaire (appendix) that aimed to assess if noise was present and the characteristics of this noise if present. No suggestion was done on how they could describe the noise and they felt free to use the word that they considered to be the most adapted. Satisfaction was evaluated asking if the patient was very satisfied, satisfied or dissatisfied with its prosthesis. When the noise was present, the X-ray was independently evaluated to assess if sign of component fracture was present. Four patients (six hips) died of unrelated cause during the follow-up. Three patients (three hips) lived outside France and could not be followed (1.3%). Nine patients (ten hips) could not be traced and are considered lost to follow-up (3.8%). Two hundred and twenty-two patients with 265 hips were therefore surveyed. Among these 265 hips, 28 experienced noise generation (10.6%). It was defined as a snap for 6 patients, as a cracking sound by 6, as rustling by 6 patients, as a squeaking by 7 patients (2.6%), a tinkling by 2 patients, one patient was unable to define the sound she felt. No factor related to the patient influenced the occurrence of noise. Twelve patients were dissatisfied with the result of the hip prosthesis, 5 of them experienced noise (41.7%); 210 were satisfied or very satisfied 23 of them experienced noise (11%); this difference was significant (p=0.002). No patients required revision for noise. The origins of noise occurrence are unknown but several hypotheses can be suggested. Squeaking may be due to absence of sufficient lubrication. Other types of noise can be due to microseparation, occult dislocation, impingement between the femoral neck and the acetabular rim but demonstration remain an issue.
