BACKGROUND: Several studies have shown that better placement of the acetabular cup and femoral stem can be achieved in total hip arthroplasty (THA) by using the computer navigation system rather than the free-hand alignment methods. However, there have been no comparisons of the relevant clinical advantages in using the computer navigation as opposed to the manual intraoperative measurement devices. The purpose of this study is to determine whether the use of computer navigation can improve postoperative leg length discrepancy (LLD) compared to the use of the measurement device. METHODS: We performed a retrospective study comparing 30 computer-assisted THAs with 40 THAs performed using a simple manual measurement device. RESULTS: The postoperative LLD was 3.0 mm (range, 0 to 8 mm) in the computer-assisted group and 2.9 mm (range, 0 to 10 mm) in the device group. Statistically significant difference was not seen between the two groups. CONCLUSIONS: The results showed good equalization of the leg lengths using both computed tomography-based navigation and the simple manual measurement device.
Acetabulum/surgery ; Adult ; Aged, 80 and over ; Arthroplasty, Replacement, Hip/instrumentation/*methods ; Body Weights and Measures ; Female ; Femur/surgery ; Humans ; Leg ; Leg Length Inequality/*surgery ; Male ; Middle Aged ; Retrospective Studies ; Surgery, Computer-Assisted ; Young Adult

The objective of this study is to examine the effect of low-magnitude, high-frequency (LMHF) loading, and anti-osteoporosis medications such as parathyroid hormone (PTH) and bisphosphonates on peri-implant bone healing in an osteoporosis model, and to assess their combined effects on these processes. Thirteen-week-old ovariectomized rats (n = 44) were divided into three groups: PTH, alendronate, and saline. After 3 weeks of drug administration, titanium implants were inserted into the tibiae. Each group was subdivided into two groups: with or without LMHF loading via whole-body vibration (50 Hz at 0.5 g, 15 min per day, 5 days per week). Rats were killed 4 weeks following implantation. Removal torque test, micro-CT analyses (relative gray (RG) value, water = 0, and implant = 100), and histomorphometric analyses (bone-to-implant contact (BIC) and peri-implant bone formation (bone volume/tissue volume (BV/TV))) were performed. Removal torque values and BIC were significantly differed by loading and drug administration (ANOVA). Post hoc analysis showed that PTH-treated groups were significantly higher than the other drug-treated groups. BV/TV was significantly enhanced by PTH administration. In cortical bone, RG values were significantly increased by loading. In trabecular bone, however, RG values were significantly increased by PTH administration. These findings suggest that LMHF loading and PTH can act locally and additively on the bone healing process, improving the condition of implant osseointegration.
Alendronate ; administration & dosage ; pharmacology ; Animals ; Dental Implantation, Endosseous ; methods ; Dental Implants ; Female ; Implants, Experimental ; Osseointegration ; drug effects ; Ovariectomy ; Parathyroid Hormone ; administration & dosage ; pharmacology ; Rats ; Tibia ; surgery ; Vibration ; Wound Healing ; drug effects