S rom

The acetabular prosthesis included Link Betacup (Link, Hamburg, Germany), Link Combicup, Depuy Pinnacle (DePuy, Warsaw, USA), and Depuy Duraloc. The femoral prosthesis included Link LCU, Depuy Corail, Depuy S-rom. The acetabular liner included metal on highly cross-linked polyethylene (MOP), third generation ceramic on ceramic (3rd-COC) and fourth generation ceramic on ceramic (4th-COC). The surgeries were performed by the posterolateral approach. After we resected the femoral head and eliminated fibrous tissue and osteophytes to reveal the true acetabulum, the acetabulum was reamed gradually to achieve the medial wall of the true acetabulum with bleeding spongy bone [10 (link)]. Porous-coated acetabular prostheses were placed in the true anatomic acetabular position or higher position with as much host bone coverage as possible. If it was difficult to reset the hip during the surgery, the shortening subtrochanteric osteotomy (SSTO) was performed in case of neurovascular damage [11 (link)]. The osteotomy length equaled the distance between the true acetabular center and the femoral head center during the trial reduction minus 15 mm. At the same time, the gluteal muscles must remain adequate tension.

A titanium arc-splayed titanium cup with hydroxyapatite coating (AMS HA Cup; Kyocera, Osaka, Japan) [18 (link)] and a cross-linked ultra-high-molecular-weight polyethylene liner (Aeonian 910 AMS Liner; Kyocera, Osaka, Japan) were used in all hips. The bearing couples were ceramic on polyethylene in 193 hips and metal on polyethylene in 22 hips. The femoral head diameters were 26 mm in 4 hips, 28 mm in 96 hips, and 32 mm in 115 hips. Two cementless stems, namely, Perfix910 HA-coated stem (Kyocera, Osaka, Japan) and S-ROM (DePuy, Warsaw, IN, USA), were used in 193 hips and 22 hips, respectively.

All THA were performed by the same group of qualified surgeons (HWL and JWZ) using a posterolateral approach. Generally, the acetabular cup is implanted using a press-fit technique in an anatomically or slightly superior place. The femoral component that best matched the broached intramedullary canal was selected. In highly dislocated cases, the capsule was cut off for reduction. Muscle and soft tissue release was performed as less as possible, and no release was made of the gluteus maximus or iliopsoas. None of the patients underwent femoral shortening osteotomy. Cementless cups (SecurFit, Stryker, USA; Pinnacle, DePuy, USA) and stems (SecurFit, Stryker; Corail, DePuy; and S-rom, DePuy) were implanted in all patients.
The patients began passive range of movement exercises 24 h postoperative and mobilized non-weight-bearing in the first week postoperative. Partial weight-bearing as tolerated was allowed for the following 6 weeks. Thereafter, progressive weight-bearing with crutches was performed, with unrestricted walking allowed after 8 or 12 weeks.

A porous‐coated acetabular component (Pinnacle, DePuy) at 15° ± 10° of anteversion and 40° ± 10° of inclination and a cementless modular femoral stem (S‐ROM, DePuy) at 15°–20° of anteversion were inserted in all Crowe type IV hips. A small acetabular prosthesis was often inserted and consequently a small femoral head was used.

All THAs were performed by three senior surgeons using the modified Watson–Jones anterolateral approach. After resecting the femoral head, medialization was carried out by reaming toward the acetabular fossa until the floor was exposed. Acetabular components were all press-fitted with targets of 40°–45° inclination and 15°–20° anteversion. Dome screws were used only if insufficient press-fitting was perceived during cup insertion. Ceramic-on-ceramic articulation was used in all operations. The femoral procedure was carried out to insert cementless implants of the desired size measured via preoperative templating. The most frequently used femoral prostheses were Bencox (Corentec, Cheon-An, South Korea), S-ROM (DePuy, Warsaw, IN, USA), Trilock (DePuy, Warsaw, IN, USA), and Corail (DePuy).