In posterior cruciate ligament (PCL)-preserving total knee arthroplasty (TKA), it is important to determine whether the PCL is properly functioning after surgery. As the PCL is partly damaged during the operation, we cannot rule out the possibility that excessive tension further damages the remaining PCL resulting in dysfunction or that initial functioning of the PCL is lost due to excessively low tension. However, it is normally difficult to examine whether the PCL has remained intact and is still functional after TKA. The objective of this study was to visualize knee joint flexion after TKA by MRI and evaluate the PCL based on these images. PCL-preserving TKA was performed in 41 knees using the Fine Total Knee System® (Nakashima Medical, Okayama, Japan) where a titanium component can be selected for both the femur and the tibia. We visualized knee flexion positions by MRI at 6 months after surgery and evaluated visualization or non-visualization of the PCL, the relationship between knee flexion angle and PCL elevation angle against the plane of the tibial joint vertical to the tibial axis, and the forms of PCL based on the MRI data.Introduction
Method
The direct anterior approach (DAA) is one of the muscle sparing approaches in total hip arthroplasty (THA). The advantages of the DAA-THA include low dislocation rate, quick recovery with less pain, and accurate implantation. However, complications related to the learning curve have been reported. The aim of this study was to analyze the first 100 cases of DAA-THA performed by 2 surgeons. The records of first 100 consecutive primary DAA-THAs performed by 2 orthopedic surgeons who have np experience of DAA-THA previously were retrospectively reviewed. All operations were performed using DAA in the supine position without the special traction table. The surgical result, the early clinical results, complications, and accuracy of prosthesis placement were investigated.Background:
Methods:
In anterior approaches for total hip arthroplasty (THA), the femoral part of the procedure requires the release of the capsule from the greater trochanter. However, it is unknown whether any other tendons of the short external rotator muscles are also damaged during capsular release procedures. The aim of this cadaveric study was to identify the bony landmarks on the greater trochanter, which indicate the individual short external rotator muscle insertions. Forty-four hip regions from 28 embalmed cadavers were dissected. At first, micro-computed tomography (micro-CT) images were obtained to identify bony impressions on the greater trochanter. Then, the soft tissues around the greater trochanter were removed and their insertions were identified to assess correlation with micro-CT images.Background:
Methods:
In TKA, it is important to make the equal extension and flexion gap (EG and FG) of the knee. Although, this principal concept applies to all knees, flexion contracture is known to have difficulties to achieve the equal EG and FG because of its smaller EG than usual. Whereas, it is also well known that PCL resection makes FG wider than EG, however, many surgeons recommend PCL resection in case of flection contracture because it is easy to manage during surgery, nevertheless the risk of further gap unbalance. Although, flexion contracture is not rare in TKA, the controversial problem of the PCL resection for the flexion contracture still remains even in today. To investigate this contradiction, we measured intra-operative EG and FG of the knee with 20 degree or more pre-operative flexion contracture. The gaps were measured by 3 different ways; a tension device system with 30 and 40 pound tension (group 1 and 2) and a spacer block system which had 1 mm increment thickness variation (group 3). The cases were 41, 46 and 51 knees in group 1, 2 and 3 respectively. Group 1 and 2 have overlapping in 27 knees.Introduction
Materials and methods
Although, the total knee arthroplasty (TKA) procedure is performed to make the same extension gap (EG) and flexion gap (FG) of the knee, it is not clear how the gaps can be created equally. According to earlier reports, the gaps after bone resection (bone gaps) differ from the gaps after the trial component of the femur is set (component gaps), because of the thickness of the posterior condyle of the femoral component and the tension of the posterior capsule. The surgeon can only check the component gaps after completing the bone resection and setting the trial component and it difficult to adjust the gaps even when the acquired component gaps are inadequate. To resolve this problem, we developed a “pre-cut trial component” for use in a pre-cut technique for the femoral posterior condyle (Fig. 1). This specially made trial component allows us to check the component gaps before the final bone resection of the femur. The pre-cut trial component is composed of an 8-mm-thick usual distal part and a 4-mm-thick posterior part of the femoral component, and lacks an anterior part of the femoral component. With this pre-cut trail component, 152 knees were investigated. The EG was made by standard resection of distal femur and proximal tibia. The FG was made by a 4 mm pre-cut from the posterior condylar line of the femoral posterior condyle (Fig. 2). The rotation of the pre-cut line is initially decided by anatomical landmarks. Once all of the osteophytes are removed and the bone gaps are checked, the pre-cut trial component is attached to the femur and the component gaps are estimated with the patella reduction (Fig. 3). In our experiments, these gaps were the same as the component gaps after the usual trial component was set via the measured resection technique. Finally, the femur is completely resected according to the measurements of the component gaps with the pre-cut trial component.Introduction
Materials and methods
The purpose of the present study was to describe the long-term results of THA for ONFH in patients with SLE. From 1994–2001, 18 cementless THAs (14 SLE patients) were included in the present study. Four hips (3 patients) were lost to follow-up. The remaining 14 hips (11 patients) were available for evaluation. The mean follow-up period was 13.1(range, 10.0–16.4) years. The follow-up rate was 77.8%. The mean age at the time of surgery was 35.2 (range, 27.4–51.0) years.Objectives
Methods
Short stem has potential advantages of bone and muscle preservation. Current papers demonstrate that direct anterior approach (DAA) is a significant minimally invasive muscle-sparing approach to total hip arthroplasty. Theoretically, a short length stem with a reduced lateral shoulder is the most appropriate design for DAA. To clarify the necessity of the standard length stem in tapered-wedge stem.Background
Objectives
Minimally invasive surgery is being widely used in the field of total hip arthroplasty (THA). The advantages of the direct anterior approach (DAA), which is used in minimally invasive surgery, include low dislocation rate, quick recovery with less pain, and accuracy of prosthesis placement. However, minimally invasive surgery can result in more complications related to the learning curve. The aim of this study was to evaluate the learning curve of DAA-THA performed by a senior resident. Thirty-three consecutive patients (33 hips) who underwent primary THA were enrolled in this study. All operations were performed by a senior resident using DAA in the supine position without the traction table. The surgeon started using DAA exclusively for all cases of primary THA after being trained in this approach for 6 months. Operative time, intraoperative blood loss, complications, and accuracy of prosthesis placement were investigated.Background
Methods
Some authors have reported that if PCL is resected, flexion gap(FG) will become wider than extension gap(EG). Sacrifice or sparing of PCL influences the equality of EG and FG. Meanwhile, measured resection technique(MRT) and gap technique(GT) has different system to adjust gap and balance. There are no criteria for choosing between CR or PS component and MRT or GT nevertheless its influences on gap and balance in TKA. EG and FG were measured intra-operatively with PCL intact to assess the characteristics of EG and FG. EG was created ordinarily. To measure FG before the final femoral cutting with PCL intact, small temporary FG was created by a pre-cut of the femoral posterior condyle with a 4-in-1 femoral cutting guide bigger than the measured size. After removal of all osteophytes, the gaps were measured by a tension device. To compare both gaps, FG was corrected by the amount of the pre-cut. According to EG and corrected FG, a component type was selected. If there was enough FG with PCL intact, CR component was implanted and if not, PS component was selected. If necessary, soft tissue was released. Finally, the optimal size of the femoral component for adequate EG and FG was estimated and rotation of the femoral component was decided. One hundred and fifty three knees with osteoarthritis were investigated.Introduction
Materials and Methods
There is no criteria to select cruciate retaining (CR) or posterior substitute (PS) component in total knee arthroplasty (TKA). In this study, extension and flexion gaps were measured intra-operatively with posterior cruciate ligament (PCL) remained to reveal characteristics of the gaps. Component type selection, CR or PS, was decided intra-operatively according to the gaps in each knee. One hundred and sixty knees with osteoarthritis were investigated. Extension gap (EG) was made by resection of 8 mm distal femur and 10 mm proximal tibia. After measurement of femoral AP size, about 4 mm bigger 4-in-1 femoral cutting guide than measured size was used for pre-cut of femoral posterior condyle[Figure 1]. With this technique, flexion gap (FG) was made 4 mm smaller than usual measured resection. The gaps were measured by a tension device with 30 pounds tension and FG was corrected by the amount of pre-cut. According to the EG and corrected FG, component type was decided. Too small FG usually needed PCL resection or (and) smaller size of femoral component to make enough final FG. On the other hand, large FG needed careful consideration to sacrifice PCL for adequate final FG. In these cases, CR component was selected usually. If necessary, soft tissue was released for good ligament balance. As the final step of the surgical procedure, the size of femoral component was decided for adequate final FG. It was changeable up to 4 mm larger than measured size[Figure 2].Introduction
Materials and methods
