Residual hip dysplasia as a risk factor for osteoarthritis in 45 years follow-up of late-detected hip dislocation

Abstract

Purpose The aim of the study was to assess the role of residual hip dysplasia as a risk factor for osteoarthritis (OA) in developmental dysplasia of the hip (DDH). Methods Fifty-one patients (60 hips) with late-detected DDH were studied. Reduction had been performed at a mean age of 19 months (range 4-65 months). On radiographs at age 8-10 years, at skeletal maturity, and at longterm follow-up, femoral head coverage was assessed using the migration percentage (MP) and centre-edge (CE) angle. OA was diagnosed if the minimum joint space width of the upper part of the joint was \2.0 mm. Results The mean age at the last follow-up was 45 years (range 43-49 years) in patients who had not undergone total hip replacement (THR). Ten patients had developed OA and eight of them had undergone THR at a mean age of 40 years (range 32-47 years). There was a clear association between OA and residual hip dysplasia. At the last follow-up, 37 hips had normal CE angles (20°or higher) and OA had developed in only two of them (5%; 95% confidence interval [CI] 1-18%). Hip dysplasia without subluxation (CE angle 10-19°) was seen in 18 hips, of which 14 hips had good outcome and four had OA (22%; 95% CI 6-48%). Subluxation occurred in five hips, of which one had a good long-term outcome and four had OA (80%; 95% CI 28-99%). In patients without late reconstructive surgery, MP increased from the age of 10 years to skeletal maturity; thereafter, no significant change occurred. The CE angle did not change significantly between the age of 10 years and the last follow-up.Conclusion Hip dysplasia without subluxation has a relatively good long-term prognosis. Subluxation is a risk factor for osteoarthritis. Thus, children with MP above 33% and CE angle under 10°should be evaluated for reconstructive surgery in order to improve the long-term outcome.

Can Combining Femoral and Acetabular Morphology Parameters Improve the Characterization of Femoroacetabular Impingement?

“…The control subjects with elevated (C 55°) alpha angles also showed a larger mean omega zone of 20% (95% CI, 18-22; p = 0.004) and 16% (95% CI, 13-19; p = 0.007) for 60°and 90°of flexion, respectively, compared with the patients with FAI. Furthermore, the mean omega zone at 0°a nd 30°was larger with 23% (95% CI, 19-27; p = 0.017) and 22% (95% CI, 19-26; p = 0.004), respectively, whereas the mean omega zone in patients with FAI was 18% (95% CI, [15][16][17][18][19][20][21][22] and 16% (95% CI, [11][12][13][14][15][16][17][18][19][20] (Table 3). In contrast, the omega zone was similar in both control groups at any of the flexion positions (0°p = 0.806, 30°p = 0.925, 60°p = 0.345, 90°p = 0.136).…”

“…Correspondingly, although the ''overall'' association between hip morphology and OA seems well substantiated [8,11,16], the correlation of isolated femoral or acetabular parameters and OA development is clear only for more extreme values and is in fact weak for values used as cutoffs to distinguish between ''normal'' and ''abnormal'' morphology [1,10,16,20]. For example, the association between OA development and cam morphotype using a cutoff value of 60°for the lateral alpha angle was found robust only for angles above 83°([ 83°: end-stage OA in 14 of 56 cases; 60°-83°end-stage OA in three of 100 cases [1]).…”

“…For example, the association between OA development and cam morphotype using a cutoff value of 60°for the lateral alpha angle was found robust only for angles above 83°([ 83°: end-stage OA in 14 of 56 cases; 60°-83°end-stage OA in three of 100 cases [1]). Similarly, for developmental dysplasia, only pronounced dysplasia is associated with OA [12,20]. We believe ''combined'' parameters such as the omega zone are better suited for diagnosis and classification of hip disorders than ''single'' parameters.…”

Dysplasia of the contralateral hip in patients with unilateral late-detected congenital dislocation of the hip

“…This different prognosis according to degree of dysplasia is in accordance with the experience from hips treated for late-detected DDH, with a poor long-term prognosis in hips with residual subluxation and a relatively good prognosis in hips with mild or moderate dysplasia. 16 At the time when these patients were treated, early derotation femoral osteotomy was commonly undertaken at my hospital, according to the view of Somerville and Scott 17 that increased femoral anteversion should be corrected early to improve the congruence of the hip and avoid recurrent subluxation. Others with great experience in the treatment of dysplasia have not agreed with this concept.…”

“…Open reduction was required in one patient. After reduction had been obtained a plaster of Paris spica was used for a mean of 9.4 months (6 to 16) with the hips in slight flexion, 40º to 60º of abduction and no or moderate internal rotation. The knees were included in the plaster in moderate flexion.…”