Periacetabular osteotomy for Tönnis grade 2 osteoarthritis secondary to hip dysplasia
Zhendong Zhang1, Ningtao Ren1, Hui Cheng1
1Senior Department of Orthopedics, The Fourth Medical Center of Chinese PLA General Hospital, 51 Fucheng Road, Beijing, China.
Purpose:
To investigate the clinical outcomes of periacetabular osteotomy (PAO) for Tönnis grade 2 osteoarthritis secondary to hip dysplasia.
Methods:
Forty-nine patients (51 hips) with Tönnis grade 2 osteoarthritis secondary to hip dysplasia, followed by a mean of 52.3 months (range: 24.1 to 95.2 months), were reviewed. As a control group, 51 patients (51 hips) with Tönnis grade 1 osteoarthritis were matched for age, surgery date, and follow-up period. All patients were evaluated clinically with the use of modified Harris hip score (mHHS) questionnaire, WOMAC score, and the 12-item International Hip Outcome Tool (iHot-12). Radiographic measurements included the lateral centre-edge angle (LCEA), Tönnis angle, and anterior centre-edge angle (ACEA). Kaplan-Meier survivorship analysis was performed to predict a five year survival rate of no osteoarthritis progression.
Results:
All functional scores and radiographic measurements of the two groups significantly improved at the final follow-up. There were no significant differences between the two groups either in functional scores or radiographic measurements. The five year survival rate of no osteoarthritis progression was 86.2% in Tönnis grade 2 group and 93.1% in Tönnis grade 1 group, respectively. In the Tönnis grade 2 group, the osteoarthritis progressed in six hips. Of which, four hips had an ACEA of < 25°. No osteoarthritis progression was found in hips with an ACEA > 40°.
Conclusions:
PAO yielded similar results for patients with Tönnis grade 2 and grade 1 osteoarthritis secondary to hip dysplasia. The majority of hips can be preserved without progression of osteoarthritis at five years postoperatively. The slight overcorrection anteriorly may be helpful in preventing osteoarthritis progression.
