Expecting the low wear property and the longevity, since October 1998, we have been using the alumina on alumina bearing for the hip arthroplasty. Until July 2008, for dysplastic 1078 hips we have implanted the bearing couple. Among them, we evaluated 86 hips in 79 patients (male 3, female 76) with the primary arthroplasty, Spongiosa Metal II Total Hip System (GHE: ESKA implants, Lübeck, Germany/Biolox Forte^®: Ceramtec AG, Plochingen, Germany), osteoarthritis secondary to developmental dysplasia, age 60 or below, and a minimum of five years follow-up. The preoperative diagnosis included the failed pelvic and/or femoral osteotomy, avascular necrosis after DDH, dislocation, and subdislocation. The average age at the surgery was 53 (27 to 60). The average of follow-up period was 6.3 (4.6 to 9.1) years. The implants have a macro-porous structure on the surface. To set the metal shell in the intended position, the sclerotic lesion was adequately resected by the chisels and then we used the acetabulum reamers. Otherwise the sclerotic lesion would prevent the reamer to go into the suitable direction. We reamed the acetabulum until the lamina interna to use the maximum size of the metal shell (i.e. to use the liner as thick as possible) and at the same time for the medialization of the hip center. To avoid impingement, the osteophyte was resected without hesitating. We added the adductor tenotomy for 19 hips, the extensive release of the flexor tendons (including the quadriceps origin, the sartroius origin, and the gluteus maximus insertion) for three hips, and the release of the extensor insertion (the gluteus maximus) for two hips, and the release of the flexor insertion (the iliopsoas) for two hips.

The hip score was improved in all patients. The average amount of the hip score was 59 before the surgery and was 90 at the final follow-up. A positive Trendelenburg sign was observed in 53 hips (62%) before the surgery and 12 hips (14%) at the final follow-up. We had no revision, no bearing failure (alumina fracture or excessive wear), no dislocation, and no squeaking in these patients. The average inclination angle of the cup was 41 (29 to 49) degrees. The average anteversion angle of the cup was 19 (13 to 27) degrees. No patient required the revision surgery. At the final follow-up, all implants were stable. In the acetabulum, the radio-lucent line was observed in two hips (2%) (zone I). In the femur the line was observed in 13 hips (15%). All lines existed in the proximal femur. There was no cystic osteolytic lesion. The prevalence of these periprosthetic reactions was less than those in the same type implant with the polyethylene on alumina bearing.

Some authors alerted that the alumina on alumina articulation should only be applied in when the optimized implant orientation is obtained so as to prevent the impingement and dislocation. Fortunately the alignment in this study was within the safe zone. However, we must always be very careful of the joint alignment, range of motion, and the muscle tension during the surgery to avoid the bearing failure, as setting an adequate alignment and obtaining a firm uncemented fixation of the cup is relatively difficult in dysplastic hips. From this view point, Spongiosa Metal II cup suits the use of the alumina on alumina bearing especially for dysplastic hips.

We apply a hydrocolloid-gel sheet (C-12, Karayaheive, Alcare, Tokyo, Japan) for the hip arthroplasty. The sheet is a kind of wound dressing film made of the Hevea sap. The Hevea sap has been widely applied for the stoma or cosmetics (e.g. facial mask, UV protection moisturizer, hair lotion). We use it since October 2004. It applies the moist wound healing mechanism without preventing the self-wound-healing. The surgical exudate is kept under the sheet to apply the moist wound healing mechanism. The sheet had been improved originally as a wound dressing material. Because of its very strong adhesiveness, we use it also as an alternative to the epidermal suture. In our method, we do not use any epidermal suture or staples. We use an anterolateral approach making an arcate incision. After the subcutaneous tissue was sutured just like as in the case of using the epidermal sutures or staples, the sheet was attached to the skin. Both the sheet and the overlaying gauze were not changed until the removals on the tenth day after surgery.

We have applied this wound closure method for 814 primary surgeries. Among them, we evaluated 56 hips in 49 patients (three males and 46 females) (including seven patients of the simultaneous bilateral surgery) with minimum of two years follow-up. The average age at the surgery was 61 (40 to 77). The diagnosis at the surgery was dysplastic osteoarthritis for 50 hips in 45 patients, primary osteoarthritis for five patients in three hips, and rheumatoid arthritis for one hip. The uncemented implants were used for all patients. In all patients, a good wound healing was obtained. The wound dehiscence occurred in two patients, however the wound healed later by attaching the hydrocolloid-gel sheet again. The hyperplastic scar was observed in one hip.

Though Orientals have less ability of wound healing than Caucasian, a satisfactory wound healing was achieved without any epidermal suture. Comparing the conventional skin closure methods, the hydrocolloid gel sheet brought about less pain; as no removal of staples was necessary, less time and labor, less medical waste, and better wound healing. As the disadvantage, some sensitive patients might mind the smell of the exudate under the gel sheet. The wound closure method using the hydrocolloid-gel sheet was very useful for the hip arthroplasty.

A special surgical technique and consideration is necessary in the total hip arthroplasty for dysplastic osteoarthritis after Kalamchi and MacEwen Type III or IV deformity (so called “Perthes-like-deformity”). There have been few reports concerning the total hip arthroplasty for “Perthes-like-deformity”. We evaluated the clinical and radiological outcome of 52 uncemented hip arthroplasties for the lesion.

We have performed 106 hips of uncemented total hip arthroplasty for dysplastic osteoarthritis after Kalamchi and MacEwen Type III or IV deformity. Among them, 52 hips of 47 patients (11 males and 41 females) were evaluated with minimum of three years follow-up. The average age at the surgery was 52 (28 to 65). The average follow-up period was 4.8 (3 to 8.1) years. Against the developmental dysplasia or dislocation, 29 hips of 26 patients had been treated by casting or surgery in infancy. Thirteen hips of 11 patients had no previous treatment before the arthroplasty. Spongiosa metal cup (GHE: ESKA implants, Lübeck, Germany) was used for 33 hips of 28 patients and Zweymüller type cup (Allo-classic cup: Zimmer Inc., Warsaw, IN, Bicon cup: Smith & Nephew Orthopedics AG, Rotkreuz, Switzerland) for 19 hips of 19 patients. Spongiosa Metal stem (GHE: ESKA implants) was used for 23 hips of 19 patients and Zweymüller type stem (Alloclassic stem: Zimmer Inc., SL stem: Smith & Nephew Orthopedics AG) for 29 hips of 28 patients. The average operative time was 108 (53 to 233) minutes. The average blood loss during the surgery was 731(150 to 1749) milliliters. The adductor tendon release was added in 28 hips of 26 patients against the severe contracture. The patients were evaluated clinically (pre-surgical history, hip score, leg length discrepancy, Trendelenburg sign, and gait function) and radiologically (ATD before the surgery, alignment, and stability of implants). Average ATD before the surgery was −2.2 (−28 to 17) millimeters. The average leg length discrepancy was 1.9 (0 to 7) centimeters before the surgery and was improved to 0.1 (0 to 1) centimeters after the surgery. The average hip score was 54 (23 to 80) before the surgery and was improved to 90 (69 to 100) after the surgery. At the final follow-up, Trendelenburg sign was positive in 14 hips of 14 patients (26.9%) and the limping was not obvious in 38 hips of 33 patients (73.1%). All implants were stable at the final follow-up.

“Perthes-like-deformity” often has the severe deformity. It has a shortening or an absence of the neck and an excessive antetorsion of the femur. When it has the coxa magna, the acetabulum is shallow, has the narrow anteroposterior diameter, and has the thin wall like the osteophyte. It is frequently accompanied by shortening of leg and contracture, as the lesion arises from the development disorders. Thus, the total hip arthroplasty, especially uncemented one, is complicated. However, the satisfactory result can be obtained by careful consideration and surgical procedure such as a provision against the bleeding and the soft tissue release.

Considerable numbers of authors have reported the change in periprothetic bone mineral density (BMD) after hip arthroplasty. However, there have been few reports concerning the BMD in the lumbar vertebra, especially for dysplastic hips.

Since 1998, we have been measuring the BMD mineral density for 2016 patients by DXA (Dual-energy X-Ray Absorptionmetry method). Among them, we evaluated the BMD in 66 postmenopausal patients with the single side primary arthroplasty, with five years or more follow-up, and also aged 60 or more. We used a DXA densitometer (DPX-IQ, GE Healthcare, Madison, WI, USA). The diagnosis at the surgery was dysplastic osteoarthritis in all patients. The average age at the surgery was 66 (60–81). All patients were female. No patients had the systematic diseases which contributed to the secondary osteoporosis. No patients had received the pharmacotherapy for osteoporosis in the whole therapeutic process. The bed rest was seven from two days after the surgery (different by the operation date). The average follow-up was 7.0 (five to ten) years.

The average BMD in the lumbar vertebra before the surgery was 0.996 (0.612 to 1.712) g/cm2. The BMD was 0.971 (0.637 to 1.402) at six month postoperatively, 0.972 (0.552 to 1.740) at one year, 1.004 (0.573 to 1.733) at two years, 1.032 (0.633 to 1.670) at three years, 1.035(0.724 to 1.688) at four years, 1.031 (0.564 to 1.679) at five years, 1.027 (0.734 to 1.647) at six years, 1.042 (0.589 to 1.389) at seven years. At the final follow-up, the BMD was 1.054 (0.589 to 1.647). In 53 patients (80%), the density at the final follow-up increased in comparison to that before the surgery. In 27 patients (41%), the density once decreased six month postoperatively. The density increased at 3 years (t=−1.919, p=0.030), four years (t=−2.523, p=0.015), five years (t=−2.381, p=0.021), seven years (t=−2.822, p=0,007), and at the final-follow-up (−4.076, p= 0.000) in comparison to that before the surgery. The activity of the patients was evaluated by the hip score. The average score was 54.5 (21 to 76) before the surgery. The average score was 88.0 (66 to 100) and increased at the final follow-up in comparison to that before the surgery (t=−13.04, p 0.000).

Some authors (eg. Bergström I, 2008, Espar I, 2008, etc.) have pointed out that the appropriate activity may increase the bone density. Presumed from the literatures, the increase of activity after the arthroplasty may have increased the BMD, though the direct correlation was not obvious between the BMD and the amount of hip score (at the final follow-up: r=0.005, p=0.972) in this study.