Aims

The preventive effects of bisphosphonates on articular cartilage in non-arthritic joints are unclear. This study aimed to investigate the effects of oral bisphosphonates on the rate of joint space narrowing in the non-arthritic hip.

A-70-year old woman underwent uncomplicated total hip arthroplasty using a titanium modular stem with a 46mm CoCr femoral head, a titanium shell, and a metal linear (Wright Medical Technology). Eight years after implantation, she presented with a painful left hip. A pelvic radiograph revealed adequate positioning of both hip implants without any signs of wear of loosening. CT scanning confirmed the presence of a 5 × 5 cm soft tissue mass in the ilium above the cup component accompanied by the iliac fracture. The patient was diagnosed as having an adverse reaction to metal debris (ARMD) after a metal-on-metal THA and revision was performed. Perioperatively?tissue necrosis and partial destruction of the abductor mechanism were found in the absence of any macroscopic infection. Both the neck trunnion and bore of the head showed slight signs of corrosion. The modular neck was revised with a ceramic 28mm head and a new dual-mobility liner(Zimmer Biomet). The iliac fracture was fixed with a porous trabecular metal augment(Zimmer Biomet).

The histopathology of tissue sample revealed extensively necrotic material with focal cellular areas of inflammatory cells containing macrophages and neutrophilas. Metalic debris was also scattered in the necrotic materials. After the revision, the patient was recovered without pain or dislocation, and iliac fracture was well fixed.

Instability is a substantial problem in the revision of ARMD. Extensive necrosis with gross deficiency of the abductor mechanism is associated with postoperative dislocation. Revision of failed MoM THA a dual-mobility device an effective strategy.

Objectives

Unicompartmental knee arthroplasty (UKA) is one surgical option for treating symptomatic medial osteoarthritis. Clinical studies have shown the functional benefits of UKA; however, the optimal alignment of the tibial component is still debated. The purpose of this study was to evaluate the effects of tibial coronal and sagittal plane alignment in UKA on knee kinematics and cruciate ligament tension, using a musculoskeletal computer simulation.

Introduction

Tibial tuberosity and trochlear groove (TT-TG) distance has been investigated for the patients with primary patellofemoral subluxation/dislocation. To date, TT-TG distance after TKA has not been evaluated, and the effect of postoperative TT-TG distance on patellar tracking is unknown. The purpose of the current study was to investigate the effect of TT-TG distance and rotational position of the femoral and tibial components on patellar tilt after TKA.

Objectives

Little biomechanical information is available about kinematically aligned (KA) total knee arthroplasty (TKA). The purpose of this study was to simulate the kinematics and kinetics after KA TKA and mechanically aligned (MA) TKA with four different limb alignments.

Introduction

Malrotation of the tibial component would lead to various complications after total knee arthroplasty (TKA) such as improper joint kinematics, patellofemoral instability, or excessive wear of polyethylene. However, despite reports of internal rotation of the tibial component being associated with more severe pain or stiffness than external rotation, the biomechanical reasons remain largely unknown. In this study, we used a musculoskeletal computer model to simulate a squat (0°–130°–0° flexion) and analyzed the effects of malrotated tibial component on lateral and medial collateral ligament (LCL and MCL) tensions, tibiofemoral and patellofemoral contact stresses, during the weight-bearing deep knee flexion.

Previously more femoral rollback has been reported in posterior-stabilized implants, but so far the kinematic change after post-cam engagement has been still unknown. The tri-condylar implants were developed to fit a life style requiring frequent deep flexion activities, which have the ball and socket third condyle as post-cam mechanism. The purpose of the current study was to examine the kinematic effects of the ball and socket third condyle during deep knee flexion.

The tri-condylar implant analyzed in the current study is the Bi-Surface Knee System developed by Kyocera Medical (Osaka, Japan). Seventeen knees implanted with a tri-condylar implant were analyzed using 3D to 2D registration approach. Each patient was asked to perform a weight-bearing deep knee bend from full extension to maximum flexion under fluoroscopic surveillance. During this activity, individual fluoroscopic video frames were digitized at 10°increments of knee flexion. A distance of less than 1 mm initially was considered to signify the ball and socket contact. The translation rate as well as the amount of translation of medial and lateral AP contact points and the axial rotation was compared before and after the ball and socket joint contact.

The average angle of ball and socket joint contact were 64.7° (SD = 8.7), in which no separation was observed after initial contact. The medial contact position stayed from full extension to ball and socket joint contact and then moved posteriorly with knee flexion. The lateral contact position showed posterior translation from full extension to ball and socket joint contact, and then greater posterior translation after contact (Figure 1). Translation and translation rate of contact positions were significantly greater at both condyles after ball and socket joint contact. The femoral component rotated externally from full extension to ball and socket joint contact, and then remained after ball and socket joint contact (Figure 2). There was no statistical significance in the angular rotation between ball and socket joint contact and maximum flexion. Translation of angular rotation was significantly greater before ball and socket joint contact, however, there was no significance in translation rate before and after ball and socket joint contact.

The ball and socket joint was proved to induce posterior rollback intensively. In terms of axial rotation, the ball and socket joint did not induce reverse rotation, but had slightly negative effects after contact. The ball and socket provided enough functions as a posterior stabilizing post-cam mechanism and did not prevent axial rotation.

Purpose

Total knee arthroplasty (TKA) is one of the most successful surgeries with respect to relieving pain and restoring function of the knee. However, some studies have reported that patients are not always satisfied with their results after TKA. The aim of this study was to determine which factors contribute to patient's satisfaction after TKA.

Introduction

Achieving high flexion after total knee arthroplasty is very important for patients in Asian countries where deep flexion activities are an important part of daily life. The Bi-Surface Total Knee System (Japan Medical Material, Kyoto, Japan), which has a unique ball-and-socket mechanism in the mid-posterior portion of the femoral and tibial components, was designed to improve deep knee flexion and long-term durability after total knee arthroplasty (Figure 1). The purpose of this study was to determine the in vivo three dimensional kinematics of Bi-Surface Total Knee System in order to evaluate and analyze the performance of this system with other conventional TKA designs currently available in the market today.

In Far East, including Japan and the Middle East, daily activities are frequently carried out on the floor. Deep flexion of the knee joint is therefore very important in these societies. Some patients who underwent total knee arthroplasty (TKA) in these countries often perform deep flexion activity, such as squatting, cross-leg sitting and kneeling. However it is still unknown that deep flexion activity affects long term durability after TKA. The purpose of this study was to examine the correlation between deep flexion and long term durability.

Between December 1989 and May 1997, 507 total knee arthroplasties were carried out in 371 patients using the Bi-Surface Knee System (Japan Medical Material, Osaka, Japan) at two institutions and routine rehabilitation program continued for one to two months after TKA. One patient who underwent simultaneous bilateral TKA was excluded because of pulmonary embolism within one month. The other 505 knees (370 patients) were divided into two groups according to the range of flexion after our routine rehabilitation program; one group (Group A: 207 knees) consisted of more than 135 degrees flexion knees and the other group (Group B: 298 knees) consists of less than 135 degrees flexion knees. Patients whose follow-up period was less than 10 years were excluded from this clinical evaluation. Range of flexion was measured preoperatively, at the time after routine rehabilitation program, and at the latest follow-up. Knee function was evaluated on the basis of Knee Society knee score and functional score preoperatively and at the latest follow-up. Kaplan-Meier survivorship analysis was performed with revision for any operation as the end point.

In Group A, the mean preoperative range of flexion was 133.0±16.3 degrees, and at the time after routine rehabilitation program, this improved to 139.7±5.1 degrees. This angle maintained to 136.2±14.3 at the latest follow-up. In Group B, the mean preoperative range of flexion was 111.6±20.4 degrees, and at the time after routine rehabilitation program, this improved to 114.5±13.6 degrees. This angle maintained to 118.2±17.8 at the latest follow-up. The Knee Society knee score and functional score was improved from 43.0±16.9 points and 39.0±20.2 points preoperatively to 95.1±5.8 points and 51.8±21.2 points at the latest follow-up, respectively in Group A. The Knee Society knee score and functional score was improved from 37.1±16.7 points and 31.9±18.4 points preoperatively to 92.5±8.7 points and 53.1±26.1 points at the latest follow-up, respectively in Group B. Kaplan-Meier survivorship at 10-year was 95.5% in Group A and 96.2% in Group B with any operation as the end point. The survivorship between Group A and Group B was not statistically significant.

Good range of flexion was maintained and Knee society score was excellent after a long time follow-up for the patients who achieved deep flexion after TKA. Deep flexion was proved not to affect long term durability in this Bi-Surface Knee System.

There are several techniques in minimally invasive total hip arthroplasty. One of the possible advantages of these techniques is early functional recovery. The purpose of the study was to evaluate possible differences in functional recovery patterns after three different techniques of minimally invasive total hip arthroplasty.

Patients and methods: Two hundreds and eighty-eight hips were recruited for this study. All operations were done without cement in all institutes. Acetabular components were Trilogy and femoral components were VerSys (Zimmer, Indiana, USA) in all hips. Mini-incision antero-lateral approach was used for 112 hips (Mini-AL group), mini-incision postero-lateral approach for 53 (Mini-PL group), and muscle sparing antero-lateral approach was used for 123 hips (MS-AL group). There were no significant differences among the three groups for age. All patients were encouraged to walk with full weight-bearing as soon as possible. Early functional outcome was assessed by the attainment of functional milestones, including the number of days post-op to walk 100m with a T-cane and to put on socks. We also analyzed pain during resting and walking, and evaluated muscle strength for abduction before surgery, at one, three, five, seven and 14 days after surgery. Pain was assessed using a visual analog scale. Muscle strength was assessed using a hand held dynamometer (MicroFET-2) in supine position. The post-pre-operative strength ratio was calculated and defined as the recovery ratio. For continuous variables, a Kruskal-Wallis test was used. For comparison among all three groups, the level of significance was set at p< 0.05. For the three multiple comparisons, the level of significance was calculated using the Bonferonni adjustment and was set at p< 0.0165.

Results: Mean of the post-op days to walk 100 meters with a T-cane was 4.09 days for MS-AL group, 4.82 for Mini-AL group, and 5.57 for Mini-PL group. MS-AL group showed a significantly earlier recovery than Mini-AL group. Mean of the post-op days to put on socks was 5.86 days for MS-AL group, 7.37 for Mini-AL group, and 9.9 for Mini-PL group. MS-AL group showed a significantly earlier recovery than Mini-AL and Mini-PL groups. There were no differences for resting pain or walking pain at any days among the three groups. There were no differences for recovery ratio of muscle strength for abduction at 3 postoperative days. At 5 days, Mini-AL showed a lower ratio than MS-AL. And at 7 and 14 days, Mini-AL showed a lower ratio than both the MS-AL and Mini-PL group.

Conclusion: Muscle sparing antero-lateral technique showed earlier recovery for walking and putting on socks than those using mini-incision techniques.

There are several techniques in minimally invasive total hip arthroplasty. One of the possible advantages of these techniques is early functional recovery. The purpose of the study was to evaluate possible differences in functional recovery patterns after three different techniques of minimally invasive total hip arthroplasty.

Patients and methods: Two hundreds and eighty-eight hips were recruited for this study. All operations were done without cement in all institutes. Acetabular components were Trilogy and femoral components were VerSys (Zimmer, Indiana, USA) in all hips. Mini-incision antero-lateral approach was used for 112 hips (Mini-AL group), mini-incision postero-lateral approach for 53 (Mini-PL group), and muscle sparing antero-lateral approach was used for 123 hips (MS-AL group). There were no significant differences among the three groups for age. All patients were encouraged to walk with full weight-bearing as soon as possible. Early functional outcome was assessed by the attainment of functional milestones, including the number of days post-op to walk 100m with a T-cane and to put on socks. We also analyzed pain during resting and walking, and evaluated muscle strength for abduction before surgery, at one, three, five, seven and 14 days after surgery. Pain was assessed using a visual analog scale. Muscle strength was assessed using a hand held dynamometer (MicroFET-2) in supine position. The post-pre-operative strength ratio was calculated and defined as the recovery ratio. For continuous variables, a Kruskal-Wallis test was used. For comparison among all three groups, the level of significance was set at p< 0.05. For the three multiple comparisons, the level of significance was calculated using the Bonferonni adjustment and was set at p< 0.0165.

Results: Mean of the post-op days to walk 100 meters with a T-cane was 4.09 days for MS-AL group, 4.82 for Mini-AL group, and 5.57 for Mini-PL group. MS-AL group showed a significantly earlier recovery than Mini-AL group. Mean of the post-op days to put on socks was 5.86 days for MS-AL group, 7.37 for Mini-AL group, and 9.9 for Mini-PL group. MS-AL group showed a significantly earlier recovery than Mini-AL and Mini-PL groups. There were no differences for resting pain or walking pain at any days among the three groups. There were no differences for recovery ratio of muscle strength for abduction at 3 postoperative days. At 5 days, Mini-AL showed a lower ratio than MS-AL. And at 7 and 14 days, Mini-AL showed a lower ratio than both the MS-AL and Mini-PL group.

Conclusion: Muscle sparing antero-lateral technique showed earlier recovery for walking and putting on socks than those using mini-incision techniques.

The precise orientation of the acetabular component is one of the important factors in total hip arthroplasty (THA). Computed tomography (CT) provides image data for accurate measurements of the orientation of the acetabular component. However, in many studies in the literature, the orientation of the acetabular component after THA has been expressed as a combination of inclination angle (IA) and version angle (VA) measured on radiographs. For measuring VA, an anteroposterior (AP) radiograph of the hip joint, or a cross-table lateral radiograph has been used. The accuracy of these radiological measurements was not thoroughly studied. The purpose of this study was to evaluate the accuracy of measurements on radiographs comparing to those on CT.

Materials and methods: Twenty-four hips (21 patients) after THA were recruited for this study. The same acetabular components (Trilogy, Zimmer, USA) had been used without cement in all hips. An AP radiograph of the pelvis, an AP radiograph of the operated hip and a cross-table lateral radiograph of the hip were taken. From the AP radiograph of the pelvis, the angle between an inter-teardrop line and a tangential line to the opening face of the acetabular component was measured and defined as inclination angle on radiographs. From the AP radiograph of the operated hip joint, the lengths of two axes of the ellipse of the acetabular component were measured and a version angle was calculated using the Lewinnek’s method. This version was defined as the version from the AP radiograph (VAP). From the cross-table lateral radiograph, another version angle was measured using a modified version of Woo’s method, which is the angle between a gravity line shown by a metal chain and a tangential line to the opening face of the acetabular component. This angle was defined as the version from a cross-table lateral radiograph (VCL). The CT scanning of the pelvis was performed with 64-MDCT scanner (Aquilion TSX-101A/HA, Toshiba Medical Systems. co). The plane passing through the bilateral anterior superior iliac spines and pubic tubercles was used as references for measurements of inclination angle and version angle from CT image data. Accuracy of CT measurements had been validated using a phantom model. The absolute value of the difference between the measured angle on the radiograph and that on CT was defined as an error. Mann-Whitney U-test was used for statistics, and the level of significance was set at p< 0.05.

Results: Mean of the error for inclination angle was 2.2 degrees (range 0–6, SD 1.3). Comparing to this, both of the two methods for measurements of version angle on radiographs showed large errors. Mean of the error was 6.9 degrees (range 0–18, SD 8.0) for VAP, and was 6.0 degrees (range 0–14, SD 6.1) for VCL. There were no significant differences between errors for VAP and that for VCL. These results suggest that the measurements of version angle on AP radiographs or cross-table lateral radiographs should not be used for the studies of orientation of the acetabular component.

Rotational acetabular osteotomy (RAO) is a circumacetabular osteotomy of the acetabulum designed to correct the dysplastic hip. In this procedure, the femoral head is covered with the articular cartilage of the acetabulum and the forces of weight-bearing are distributed more evenly. The purpose of this study was to determine whether RAO is effective in delaying the onset of arthrosis in patients with painful hip dysplasia.

We determined the outcome of 20 female patients in whom RAO was performed between 1975 and 1984; all were aged 20 to 29 years at the time of surgery. The pre-operative centre-edge angle of Wiberg was 0 or negative with proximal subluxation of the femoral head. Of these, 10 were lost to follow-up before the age of 42. In these patients, however, radiographs showed no signs of arthrosis at the last follow-up. The remaining 10 patients were examined 15 to 25 years after surgery, when they were 42 to 47 years old. Radiographs revealed findings of arthrosis in only two of them who had had the secondary acetabulum before surgery.

To evaluate the efficacy of preventive medicine, it is necessary to compare the results of intervention with the natural course of the disease. Wiberg reported on the natural history of seven female patients with severe hip dysplasia in 1939. When these patients were 13 to 34 years old, radiographs demonstrated no sign of arthrosis and the centre-edge angle was equal to or less than 12 degrees with proximal subluxation of the femoral head. These hips deteriorated to advanced arthrosis by the age of 42 years. Thus the outcome of our patients was significantly better than the natural course.

In conclusion, our study suggests that RAO is effective in delaying the onset of arthrosis in patients with painful hip dysplasia.