ObjectiveTo explore the surgical technique and the effectiveness of reconstructing the hip center in total hip arthroplasty (THA) for developmental dysplasia of hip (DDH). MethodsBetween January 2004 and January 2010, 29 patients (32 hips) with DDH underwent THA. There were 6 males (6 hips) and 23 females (26 hips), aged 45-67 years (mean, 50.6 years). The locations were left side in 22 hips and right side in 10 hips. According to Crowe classification, 12 hips were rated as Crowe I and 20 hips as Crowe II. The patients had limb length discrepancy of 1.9-4.4 cm. The Harris score was 50.7 ± 8.6. ResultsAll incisions healed by first intension. Posterior hip dislocation occurred in 1 case (1 hip) after operation. All patients were followed up 2 years-4 years and 6 months (mean, 2.3 years). The lower limbs were lengthened by 0.5-5.8 cm (mean, 2.5 cm). The Harris score was 87.7 ± 5.9 at 1 year after operation, showing significant difference when compared with preoperative score (t=21.77, P=0.00). X-ray films showed loosening of acetabular component in 1 case (1 hip) and displacement of acetabular component with too large abduction angle in 1 case (1 hip); no loosening and subsidence of acetabular or femoral components occurred in the other patients during follow-up. The horizontal location of hip center, the vertical distance between teardrop and the hip center, the vertical acetabular abduction angle, and the femoral offset were better than those before operation (P lt; 0.05). ConclusionFor DDH patients, reconstructing the hip center in THA can lengthen the limb, improve the joint function, and reduce the failure rate of joint replacement.
ObjectiveTo summarize the design and the biomechanical characteristics of Sivash-range of motion femoral modular stem (S-ROM) prosthesis and mainly to introduce its clinical use in developmental dysplasia of hip (DDH) and hip revision. MethodsLiterature concerning S-ROM prosthesis was extensively reviewed and analyzed. ResultsThe S-ROM prosthesis based on the modularity feature can reach press-fit in metaphysis and diaphysis of femur concurrently. Additionaly, S-ROM prosthesis can fit for anatomic differences of the DDH femur and is capable of use in correction osteotomy and hip revision. ConclusionModular junctions of S-ROM prosthesis increase the potentials of implant fracture and metallic debris production, so further follow-up study is needed to verify the long-term effectiveness.
ObjectiveTo investigate the value of cementless total hip arthroplasty (THA) for the treatment of Crowe type Ⅲ developmental dysplasia of hip (DDH) in adults. MethodsBetween September 2013 and September 2015, 50 patients (51 hips) with Crowe type Ⅲ DDH were treated. There were 20 males (20 hips) and 30 females (31 hips), with the average age of 39 years (range, 19-55 years). The left side was involved in 34 cases, the right side in 15 cases, and both sides in 1 case. All patients had the symptoms of limp walking and hip pain. The disease duration was 10-47 months (mean, 26 months). The sign of "4" number test and Trendenleburg sign were positive; the Harris score was 38.9±7.1. The bilateral lower extremities discrepancy was 2.5-4.0 cm (mean, 3.3 cm) before operation. All the patients underwent cementless THA, and acetabulum by structural femoral head autograft was performed in 28 cases (28 hips). ResultsAfter operation, the incision healed by first intention. Only 2 patients (2 hips) had femoral nerve palsy, and 7 patients (7 hips) had leg swelling, which were cured after symptomatic treatment. All the patients were followed up 6-18 months (mean, 10 months). The sign of limp walking was improved after operation, hip pain was relieved in 46 patients (46 hips) and only 4 patients (5 hips) still had mild pain. The X-ray films showed bony healing at 3-6 months (mean, 5 months) after operation. At last follow-up, the patients had equal limb length with the discrepancy less than 1 cm (mean, 0.4 cm). At last follow-up, the Harris score was significantly increased to 91.2±2.8 (t=-79.77, P=0.00). ConclusionThe cementless THA is an effective method to treat Crowe type Ⅲ DDH in adults.
ObjectiveTo investigate the influence of the degree of acetabular deformity and the learning-curve on the acetabular cup positions in total hip arthroplasty (THA) for adults with developmental dysplasia of hip (DDH). MethodsBetween January 2008 and December 2015, 130 patients (144 hips) with DDH underwent primary THA, and the clinical data were analyzed retrospectively. Fifty-three patients (59 hips) were admitted before 2012, and 77 patients (85 hips) were treated after 2012. There were 32 males and 98 females, aged from 31 to 83 years (mean, 61). Unilateral replacement was performed in 116 cases and bilateral replacement in 14 cases. Of 144 hips, 48 hips were rated as Crowe type I, 57 hips as type II, and 39 hips as type of III/IV. The standard pelvic radiograph was taken within 1 week after operation. The mediCAD software was adopted to measure the angle of anteversion and abduction, bony coverage, and the distance between true rotating center and optimal rotating center to the connection of teardrops and the horizontal distance between two centers to evaluate the qualified rate of acetabular cup positions. ResultsCompared with the patients with the same type in 2013-2015 group, the anteversion angle and qualified rate of acetabular cup position significantly decreased in patients with Crowe I (P < 0.05); the horizontal distance significantly increased and qualified rate of acetabular cup position significantly decreased in patients with Crowe II (P < 0.05); and the anteversion angle significantly decreased and the horizontal distance significantly increased in patients with Crowe III/IV (P < 0.05) in 2008-2012 group. But no significant difference was shown in the other indexes (P > 0.05). In all Crowe types, the vertical distance between the true rotating center and the optimal rotating center increased with the degree of acetabular deformity in both 2008-2012 group and 2013-2015 group, showing significant difference (P < 0.05), but no significant difference was found in the other indexes (P > 0.05). ConclusionFor adults with acetabular dysplasia, there are high potential risks for unsatisfactory acetabular cup positions during primary THA. So it is necessary to evaluate acetabular deformities and to sum up operative experience so as to improve the accuracy of cups installation.