Background: Conventional radiographs are routinely used to evaluate acetabular bone loss as part of the follow-up in patients who undergo total hip arthroplasty (THA). The objective of this study was to examine the accuracy and specificity of conventional radiographs reviewed by arthroplasty surgeons in detecting acetabular bone loss in patients with prior THA. Methods:Using a cadaveric pelvic model, a defined percentage of bone was incrementally removed from the posterior acetabular column, followed by implantation of uncemented cups into both acetabula. Ten orthopedic arthroplasty surgeons, blinded to the defect sizes, assessed the percentage of bone defect using standard anteroposterior, Judet and oblique conventional radiographs. Results:Observers were unable to accurately grade bone defects using conventional radiographs. For defects less than 50%, observers reported on average a defect of 11%. Although observer estimates of defects 50% or more increased, these treatmentaltering bone deficiencies remained grossly underestimated, with a sensitivity and specificity of 36.6% and 97.6%, respectively. Conclusion:Conventional radiographs reviewed by experienced arthroplasty surgeons do not reliably detect small bone lesions (< 50%). Although more successful in detecting larger bone lesions, surgeons tend to underestimate actual bone loss. Computed tomography scanning may be indicated if accurate estimation of acetabular bone loss is required in patients who have undergone previous THA.Contexte : On utilise habituellement les radiographies ordinaires pour évaluer la perte osseuse au niveau de l'acétabulum lors du suivi des patients qui subissent une chirurgie pour prothèse totale de la hanche (PTH). L'objectif de la présente étude était de vérifier la précision et la spécificité des radiographies ordinaires examinées par des chirurgiens spécialistes de l'arthroplastie pour le dépistage de la perte osseuse acétabulaire chez des patients ayant déjà subi une PTH.Méthodes : Sur un modèle de bassin de cadavre, nous avons graduellement retiré un pourcentage prédéfini de tissu osseux de la colonne acétabulaire postérieure, après quoi nous avons implanté des cotyles prothétiques non cimentés dans les 2 acétabu-lums. Dix chirurgiens orthopédistes spécialistes de l'arthroplastie qui ne connaissaient pas la taille des anomalies ont évalué le pourcentage de perte osseuse à l'aide de radiographies ordinaires antéropostérieurs, de Judet et obliques. Résultats :Les observateurs se sont révélés incapables d'évaluer avec précision les pertes osseuses à l'aide des radiographies ordinaires. Pour les anomalies inférieures à 50 %, les observateurs ont signalé en moyenne des anomalies de 11 %. Même si les estimations des anomalies de 50 % ou plus par les observateurs étaient plus élevées, ces déficits osseux qui modifient le traitement sont restés largement sous-estimés, avec une sensibilité et une spécificité de 36,6 % et 97,6 %, respectivement. Conclusion :Les radiographies ordinaires examinées par des spécialistes de l'arthroplastie...

Patients with Down's syndrome (DS) have an increased incidence of coxarthrosis which may become symptomatic with prolonged life expectancy. We present seven consecutive patients (nine hips) with DS who had primary total hip arthroplasty (THA). Average clinical and radiological follow-up was 9.9±6.4 years (range 2-22.25). Harris hip scores (HHS) improved significantly (p<0.01) from 41.1 (range 18.5-65) to 80.2 (range 67.5-91) at latest follow-up. Two patients required revision arthroplasty for stem loosening at 16 (osteolysis) and six years (trauma) following THA, respectively. Six of the THAs required a constrained liner. No dislocations or deep infections were encountered. We contend that THA is a reliable surgical intervention in patients with DS and may be performed in symptomatic patients.

Hip osteoarthritis is prevalent in 8% to 28% of patients with Down syndrome. Presence of disabling hip pain is increased along with prolonged life expectancy, suggesting total hip arthroplasty (THA). Seven consecutive patients (9 hips) with Down syndrome underwent primary THA. Coxarthrosis was secondary to developmental hip dysplasia in 6 patients and slipped capital epiphysis in 1 patient. In 5 patients (7 hips), a previous hip surgery was performed. Average clinical and radiological follow-up was 9.9±6.4 years (range, 2-22.5 years; median, 9.3 years). Average patient age at THA was 34.8±7.5 years (range, 25- 47 years; median, 35.4 years). In 2 patients (3 hips), a trochanteric slide was used for the surgical approach, while a lateral transgluteal approach was used in the remaining patients. One-way analysis of variance test was used to compare Harris Hip Scores (HHS) at postoperative follow-up.Harris Hip Scores improved significantly (P=.008) from 4.1±15.1 (range, 18.5-65; median, 45) to 84.8.3±7.7 (range, 70-93; median, 85.8) at 4-year follow-up. Harris Hip Scores (average, 70.9±6.2; range, 66.5-80; median, 68) remained essentially unchanged (P=.43) at 8-year follow-up. Two patients required revision THA for stem loosening at 6 and 16 years post-THA, respectively. The first patient is 7 years post-revision and ambulates without aids. The second patient is 6.1 years post-revision and ambulates with a walker. Six of the THAs required a constrained liner. No dislocations or deep infections were encountered. At last follow-up, all patients had a functional range of motion without evidence of discomfort related to their THA.

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