Abstract
Purpose
Dysplastic acetabulum (DDH) have some difficulty even if with conventional approach of THA. Indication or contraindication is not clear with MIS THA. The purpose of this study was to evaluate complications with mini antero-lateral approach for DDH patients.
Materials & Methods
1523 DDH hips were evaluated. Follow-up periods were averaged 36 mos. (24–74). 612 were Crowe I, 628 of II, and 283 of III. Crowe IV hips were contra-indicated. Leg length discrepancy (LLD) before and after surgery, OR time, complications during and after surgery, and length of hospital stay were evaluated.
Results
Average LLD before surgery was 1.3cm in Crowe I, 1.8cm in II, 3.3cm in III, but recovered within 5 mm after surgery. Average OR time was 56 minutes, 68, and 96 (p<0.05), respectively. Crowe II with contractured hips had more OR time (>75 min) compared to no contractured hips (<65 min) (p<0.05). Three of type I, 4 of II, 6 of III with osteoporosis and contractured hip patients had posterior trochanteric tip fracture within 2 weeks because of disuse bone atrophy or obesity (BMI>30). Two acetabular cups were revised with Crowe III because of surgical errors. We had 8 dislocations, 2 infections and 12 anterior calcar linear fractures, but fixed with wiring. No other complication has occurred. After 300 cases, lerning curve was stable around 60 minutes in skin to skin surgical time. Harris hip score was improved 92 at the final follow-up.
Discussion & Conclusion
Crowe I and II patients had no severe complication. Care must be taken for Crowe III with 2.5cm or more LLD with contractured hip, severe osteoporosis, or anteverted femoral neck. These type of patients need to change conventional approach. Capsular release around piriformis fossa need to make a proper alignment before stem broaching. Care must be taken for obtaining proper combined anteversion of DDH with higher femoral neck anteversion.
