Total knee arthroplasty (TKA) has achieved excellent clinical outcomes and functional performances. However, younger and Asian patients require even greater implant longevity and higher flexion. It is necessary for much further functional upgrading to design TKA with mobility and stability. Therefore, we determined the relationship between mobility and stability of TKA. We evaluated the force of constraint of femorotibial surfaces in two types of designs in order to measure the property of femorotibial surfaces. The anatomical geometry knee (AGK) has an asymmetrical design, which restores the anatomical jointline in both sagittal and coronal planes, and is expected to permit normal kinematics, with cruciate-retaining fixed type. The functional designed knee (FDK) has a symmetrical design, and enhances concave femorotibial surfaces with cruciate-retaining mobile type. We performed mechanical tests to measure the force of constraint regarding anterior-posterior (AP) and internal-external (IE) rotational direction in extension position, 90-degree flexion and a maximum flexion of 140-degree. The force load to AP direction of tibial tray was measured when the femoral component moved plus or minus 10 millimeters. The moment load to IE rotational direction of tibial tray was measured when the femoral component moved plus or minus 20 degrees. The vertical load of 710N has been loaded on the femoral component during this test.Background:
Methods:
The objective of this study was to verify the long-term outcome of transtrochanteric anterior rotational osteotomy (ARO) for osteonecrosis of the femoral head (ONFH) in young patients with systemic lupus erythematosus (SLE). Consecutive series of 21 symptomatic ONFH patients with SLE (33 hips), aged 20 to 40 years, underwent ARO between 1980 and 1988. We reviewed the cases of 16 patients (25 hips), which represents a 76% rate of follow-up. Patients included 4 men and 12 women who had a mean age of 29 years at the time of surgery. A Kaplan-Meier curve was used for the survivorship analysis of ARO. Patients with surviving hips were evaluated by the modified Oxford hip score and the Medical Outcomes Study Short Form 36 (SF-36).Introduction
Methods
Transtrochanteric curved varus osteotomy is one of the effective joint-preserving operations for osteonecrosis (ON) of the femoral head. We correlated various factors with the radiological outcome of this procedure. We reviewed 74 hips in 63 patients who had a minimum follow-up of 5 years after transtrochanteric curved varus osteotomy for the treatment of ON. There were 28 men and 35 women who had a mean age of 33 years (range, 15 to 68 years) at the time of surgery. Clinical assessment was made based on the Harris hip score (HHS). Radiographically, we investigated various factors; affected lesion, stage and type (localization of the necrotic lesion) of ON, varus degree, post-operative intact ratio, progression of collapse, and joint-space narrowing. On the basis of postoperative radiographs, the hips were divided into 2 groups (Group I: either the progression of collapse or joint-space narrowing, Group II: neither progression of collapse or joint-space narrowing). The related factors with radiological outcome were analyzed by using multivariate analysis (Stepwise discriminant analysis).Introduction
Methods
Subchondral insufficiency fracture of the femoral head (SIF) is a recently proposed concept. It is generally seen in elderly people, however, some young adults have also been reported to suffer from this fracture. The purpose of this study was to investigate the clinical results of a transtrochanteric anterior rotational osteotomy (ARO) performed in young adults with SIF. This study focused on young SIF cases (age range from 10 to 29 years). Five patients were diagnosed to have SIF at our institution and conservative treatment was initially performed. The symptoms resolved in 1 case while the other 4 cases showed progression of a collapse. In these 4 cases, ARO was performed, since the fractured area was located in the anterosuperior portion of the femoral head. The average age of the patients was 22 years (range, 16 to 29 years) at the time of surgery, consisting of 2 men and 2 women.Introduction
Methods
Subchondral insufficiency fracture of the femoral head (SIF) often occurs in osteoporotic elderly patients. Patients usually suffer from acute hip pain without any obvious antecedent trauma. Radiologically, a subchondral fracture is seen mainly in the superolateral portion of the femoral head. The T1-weighted magnetic resonance (MR) images show a low-intensity band in the subchondral area of the femoral head, which tends to be irregular, disconnected, and convex to the articular surface. This low-intensity band in SIF was histologically proven to correspond to the fracture line with associated repair tissue. Some cases of SIF resolve after conservative treatment, while others progress until collapse, thereby requiring surgical treatment. The prognosis of SIF remains unclear. This study investigated the risk factors that influence the prognosis of SIF based on the progression of the collapse. Between June 2002 and June 2008, seventeen patients diagnosed as SIF were included in this study. Sequential radiographs were evaluated for the presence of progression of the collapse. The clinical profiles, including the age, body mass index (BMI), follow-up period and Singh index were examined. The morphological characteristics of the low intensity band on the T1-weighted magnetic resonance images were also examined, with regard to the band length, band thickness and band length ratio; which is defined as a proportion of the band length to the weight-bearing portion of the femoral head.Introduction
Methods
Subchondral insufficiency fracture (SIF) needs to be differentiated from osteonecrosis. The purpose of this study was to evaluate the imaging and histopathological findings of patients 60 years or older with radiological evidence of subchondral collapse of the femoral head. We reviewed 77 consecutive hips in 56 patients aged 60 years or older, which showed subchondral collapse on radiographs. According to the shapes of low-intensity bands on T1-weighted images of magnetic resonance imaging (MRI), the patients were divided into 2 groups. Group A showed a concavity of the articular surface: characteristic appearances of osteonecrosis, and Group B showed an irregular convexity of the articular surface: characteristic appearances of SIF.Introduction
Methods
In Japan, idiopathic osteonecrosis of the femoral head (ONFH) is designated as a specified rare and intractable disease in patients for whom medical care is subsidized through the Specified Disease Treatment Research Program. Each patient is approved for the subsidy based upon a prefectural governmental review after filing an application together with a clinical research form documenting the patient's medical history, laboratory/clinical findings, and treatment. The purpose of this study was to conduct a fact-finding study of ONFH patients in the Fukuoka Prefecture based on clinical research forms of the Specified Disease Treatment Research Program. The distribution by gender and age of ONFH patients who filed an application for subsidy under this program between 1999 and 2008 was investigated on the basis of clinical research forms in the Fukuoka Prefecture. For comparative purposes, we also investigated the distribution by gender and age of ONFH patients who had a final diagnosis of ONFH at our institution during the past three years.Background
Methods
Transposition osteotomy of the acetabulum (TOA) was the first periacetabular osteotomy for the osteoarthritis hips due to acetabular dysplasia, in which the acetabulum was transposed with articular cartilage. TOA improves coverage of the femoral head to restore congruity and stability, and also prevent further osteoarthritis deterioration and induce regeneration of the joint. Many good clinical outcomes have been reported for such periacetabular osteotomies for osteoarthritis of the hips at an early stage. In contrast, the clinical outcome is controversial for those hips at an advanced stage, in which the joint space has partly disappeared. The purpose of this study was to investigate whether TOA is an appropriate option for treatment of osteoarthritis of the hips at the advanced stage by comparing with matched control hips at the early stage. Between 1998 and 2001, TOA was performed in 104 hips of 98 patients. Sixteen of 17 hips (94%) with osteoarthritis at the advanced stage were examined and compared with 37 matched control hips at the early stage. The mean age at the operation was 48(38–56) and the mean follow-up period was 88 (65–107) months. TOA corrected the acetabular dysplasia and significantly improved containment of the femoral head. No hips had secondary operations including THA. Clinical scores were also significantly improved in both of the groups. In the advanced osteoarthritis cases, there was a tendency for abduction congruity before transposition osteotomy of the acetabulum to reflect the clinical outcome. TOA is a promising treatment option for the advanced osteoarthritis of the hips as well as for those patients at the early stage when preoperative radiographs show good congruity or containment of the joint.
ROBODOC is a well known tool for a computer assisted arthroplasty. However, the incision tends to enlarge with the system because of the restriction of range of motion. We have developed the robot system for minimally invasive arthroplasty. This report shows the accuracy of our system composed of original planning software, navigation and bone cutting robot. We took the DICOM data of cadaver knees from computed tomography. The data were transferred to the workstation for planning. Matching points for registration and cutting planes were determined on the planning software. Cutting tool was the 6th robot which was able to recognize the locations of its apex and the cadaver knee with navigation system. We made five planes for TKA and two planes for UKA on femur. Then we made one plane on tibia. We evaluated the accuracy by measurement the location of cutting plane under navigation system and by CT data. The registration errors of femur and tibia were less than 1.0mm about cadaver knees. The errors of cutting planes were 1.3 mm about the distal end of femur and 0.5 mm about the proximal end of tibia. The accuracies of the angles of cutting planes were 1.9 degrees and 0.8 degrees compared to the mechanical axis. The errors of anterior and posterior plane of femur were increased compared to the distal plane. It was because the accuracy of registration were correct in axial direction but was not satisfied in rotational direction. The error was considered by the location of points which decided the rotation alignment. We will make effort to minimize the errors of registration and put it into practical use as soon as possible.
In order to clarify how intra-articular lesions
influence the survival of a periacetabular osteotomy in patients
with dysplasia of the hip, we performed an observational study of
121 patients (121 hips) who underwent a transposition osteotomy
of the acetabulum combined with an arthroscopy. Their mean age was
40.2 years (13 to 64) and the mean follow-up was 9.9 years (2 to
18). Labral and cartilage degeneration tended to originate from
the anterosuperior part of the acetabulum, followed by the femoral
side. In all, eight hips (6.6%) had post-operative progression to
Kellgren–Lawrence grade 4 changes, and these hips were associated
with the following factors: moderate osteoarthritis, decreased width
of the joint space, joint incongruity, and advanced intra-articular
lesions (subchondral bone exposure in the cartilage and a full-thickness
labral tear). Multivariate analysis indicated subchondral bone exposure
on the femoral head as an independent risk factor for progression
of osteoarthritis (p = 0.003). In hips with early stage osteoarthritis,
femoral subchondral bone exposure was a risk factor for progression of
the grade of osteoarthritis. Although the outcome of transposition osteotomy of the acetabulum
was satisfactory, post-operative progression of osteoarthritis occurred
at a high rate in hips with advanced intra-articular lesions, particularly
in those where the degenerative process had reached the point of
femoral subchondral bone exposure.
The transfer of part of the ulnar nerve to the musculocutaneous nerve, first described by Oberlin, can restore flexion of the elbow following brachial plexus injury. In this study we evaluated the additional benefits and effectiveness of quantitative electrodiagnosis to select a donor fascicle. Eight patients who had undergone transfer of a simple fascicle of the ulnar nerve to the motor branch of the musculocutaneous nerve were evaluated. In two early patients electrodiagnosis had not been used. In the remaining six patients, however, all fascicles of the ulnar nerve were separated and electrodiagnosis was performed after stimulation with a commercially available electromyographic system. In these procedures, recording electrodes were placed in flexor carpi ulnaris and the first dorsal interosseous. A single fascicle in the flexor carpi ulnaris in which a high amplitude had been recorded was selected as a donor and transferred to the musculocutaneous nerve. In the two patients who had not undergone electrodiagnosis, the recovery of biceps proved insufficient for normal use. Conversely, in the six patients in whom quantitative electrodiagnosis was used, elbow flexion recovered to an M4 level. Quantitative intra-operative electrodiagnosis is an effective method of selecting a favourable donor fascicle during the Oberlin procedure. Moreover, fascicles showing a high-amplitude in reading flexor carpi ulnaris are donor nerves that can restore normal elbow flexion without intrinsic loss.
In order to investigate the mechanisms of collapse in osteonecrosis of the femoral head, we examined which part of the femoral head was the key point of a collapse and whether a collapsed region was associated with the size of the necrotic lesion. Using 30 consecutive surgically removed femoral heads we retrospectively analysed whole serial cut sections, specimen photographs, specimen radiographs and histological sections. In all of the femoral heads, collapse consistently involved a fracture at the lateral boundary of the necrotic lesion. Histologically, the fractures occurred at the junction between the thickened trabeculae of the reparative zone and the necrotic bone trabeculae. When the medial boundary of the necrotic lesion was located lateral to the fovea of the femoral head, 18 of 19 femoral heads collapsed in the subchondral region. By contrast, when the medial boundary was located medial to the fovea, collapse in the subchondral region was observed in four of 11 femoral heads (p = 0.0011). We found that collapse began at the lateral boundary of the necrotic lesion and that the size of the necrotic lesion seemed to contribute to its distribution.
We investigated the factors related to the radiological outcome of a transtrochanteric curved varus osteotomy in patients with osteonecrosis of the hip. We reviewed 73 hips in 62 patients with a mean follow-up of 12.4 years (5 to 31.1). There were 28 men and 34 women, with a mean age of 33.3 years (15 to 68) at the time of surgery. The 73 hips were divided into two groups according to their radiological findings: group 1 showed progression of collapse and/or joint-space narrowing; group 2 had neither progressive collapse nor joint-space narrowing. Both of these factors and the radiological outcomes were analysed by a stepwise discriminant analysis. A total of 12 hips were categorised as group 1 and 61 as group 2. Both the post-operative intact ratio and the localisation of the necrotic lesion correlated with the radiological outcome. The cut-off point of the postoperative intact ratio to prevent the progression of collapse was 33.6%, and the cut-off point to prevent both the progression of collapse and joint-space narrowing was 41.9%. The results of this study indicate that a post-operative intact ratio of 33.0% is necessary if a satisfactory outcome is to be achieved after this varus osteotomy.
Combined anteversion (CA) is defined as the sum of the anteversions of acetabular and femoral components. In this study, we determined the appropriate CA in a variety of femoral versions using a total hip arthroplasty model. In addition, we also examined the usefulness of a changeable neck to improve range of hip motion in these cases. Using a THA model, the range of motion (ROM) was tested in various CA values obtained by changing the anteversion of a cup in six increments after setting the femoral anteversion to 20° or 60° anteversion and 20° retroversion. The angle of the changeable neck was changed in 11 increments of 5°. To evaluate stability, the range of internal rotation at 90° flexion, the external rotation at 0° extension, and the range flexion was measured when any impingement occurred prior to dislocation. We defined the required ROM that met 40° internal rotation, 30° external rotation, and 110° flexion. In normal 20° anteversion group, the required ROM was achieved with CA between 30° and 50° without using any changeable necks. In excessive anteversion 60° group, the range of external rotation was less than 10° even when the acetabular component was set 10° retroverted, because of the bone impingement between the greater trochanter and the posterior acetabulum. When 25° retroverted changeable neck was used, ROM improved to 30° external rotation and satisfied the required ROM. In 20° retroversion group, the internal rotation angle was 31° even when the acetabular component was opened 35° anteverted, because of anterior neck-liner impingement. When 25° anteverted changeable neck was used, ROM improved to 39° internal rotation and 130° flexion. In cases with normal anteversions, the required ROM can be achived by adjusting CA. In cases with excessive anteversion or retroversion, there was a limitation of the CA adjustment. The use of changeable necks allows for further improvement of ROM by compensating femoral anteversions.
Treating Crowe type 3 or 4 of hips tends to be technically difficult when performing total hip arthroplasty (THA) due to the severely dysplastic acetabulum and proximal femur in addition to a high dislocation of the hip. Since the socket is limited to being placed at the original hip center, a femoral shortening osteotomy is often required in order to prevent neurovascular problems. This osteotomy will need the stability of the femoral stem with both the proximal and the distal femoral bones. We used the modular S-ROM stem, which has a valuable proximal structure and a distal flute structure to stabilize the stem with the proximal and distal femoral fragments. The purpose of this study was to report the clinical and radiographic results of the primary THA with a shortening osteotomy while also using the S-ROM prosthesis. Between 1994 and 2004, primary THA using the S-ROM prosthesis was performed on 7 hips in 6 cases (1 male, 5 females). Crowe type 3 or 4 was observed in one and 6 hips, respectively. The mean age at operation was 56 years old (range 51~60). The mean follow-up period was 41 months (range 24~56 months). Four hips had previously undergone a subtrochanteric valgus osteotomy. All hips underwent a step-cut femoral osteotomy at the proximal metaphysis for the shortening and/or correction of angulations with on-lay chip bone grafts. All of the used stems were straight type. The clinical outcome was evaluated using the clinical scoring system of hip joints established by the Japanese Orthopaedic Association (JOA). According to a 100 point scale, pain was determined to be 40, ROM was 20, gait was 20 and ADL was 20. No hips had undergone any revision surgery as of the most recent follow-up. Union was achieved at the osteotomy site in all hips. Neither osteolysis nor a loosening of the implant was radiographically observed. The mean JOA score before THA and at the last follow-up was 41 (31–48) and 81 (62–91) points, respectively. The mean postoperative days to start full weight bearing was 53 days (range 49~70). In two cases (28%), a procedure using circular wiring was performed to treat a crack in the proximal femur. The S-ROM prosthesis was thus found to be useful for primary THA with a shortening metaphyseal femoral osteotomy for hips in patients with Crowe type 3 or 4 developmental dysplasia.
Transtrochanteric curved varus osteotomy was designed to avoid some of the disadvantages of varus wedge osteotomy, such as post-operative leg-length discrepancy. In this retrospective study we investigated the leg-length discrepancy and clinical outcome after transtrochanteric curved varus osteotomy undertaken in patients with osteonecrosis of the femoral head. Between January 1993 and March 2004, this osteotomy was performed in 42 hips of 36 patients with osteonecrosis of the femoral head. There were 15 males and 21 females with a mean age at surgery of 34 years (15 to 68). The mean follow-up was 5.9 years (2.0 to 12.5). The mean pre-operative Harris hip score was 64.0 (43 to 85) points, which improved to a mean of 88.7 (58 to 100) points at final follow-up. The mean varus angulation post-operatively was 25° (12° to 38°) and the post-operative mean leg-length discrepancy was 13 mm (4 to 25). The post-operative leg-length discrepancy showed a strong correlation with varus angulation (Pearson’s correlation coefficient; r = 0.9530, p <
0.0001), which may be useful for predicting the leg-length discrepancy which can occur even after transtrochanteric curved varus osteotomy.
We have studied the effect of hydroxyapatite (HA) coating in 15 ovariectomised and 15 normal rats which had had a sham procedure. Twenty-four weeks after operation, HA-coated implants were inserted into the intramedullary canal of the right femur and uncoated implants into the left femur. The prostheses were removed four weeks after implantation. Twelve specimens in each group had mechanical push-out tests. Sagittal sections of the other three were evaluated by SEM. The bone mineral density (BMD) of the dissected left tibia was measured by dual-energy x-ray absorptiometry. The difference in BMD between the control and ovariectomised tibiae was 35.01 mg/cm2 (95% CI, 26.60 to 43.42). The push-out strength of the HA-coated implants was higher than that of the uncoated implants in both groups (p <
0.0001), but the HA-coated implants of the ovariectomised group had a reduction in push-out strength of 40.3% compared with the control group (p <
0.0001). Our findings suggest that HA-coated implants may improve the fixation of a cementless total hip prosthesis but that the presence of osteoporosis may limit the magnitude of this benefit.
Particulate wear debris is associated with periprosthetic inflammation and loosening in total joint arthroplasty. We tested the effects of titanium alloy (Ti-alloy) and PMMA particles on monocyte/macrophage expression of the C-C chemokines, monocyte chemoattractant protein-1 (MCP-1), monocyte inflammatory protein-1 alpha (MIP-1α), and regulated upon activation normal T expressed and secreted protein (RANTES). Periprosthetic granulomatous tissue was analysed for expression of macrophage chemokines by immunohistochemistry. Chemokine expression in human monocytes/macrophages exposed to Ti-alloy and PMMA particles in vitro was determined by RT-PCR, ELISA and monocyte migration. We observed MCP-1 and MIP-1α expression in all tissue samples from failed arthroplasties. Ti-alloy and PMMA particles increased expression of MCP-1 and MIP-1α in macrophages in vitro in a dose- and time-dependent manner whereas RANTES was not detected. mRNA signal levels for MCP-1 and MIP-1α were also observed in cells after exposure to particles. Monocyte migration was stimulated by culture medium collected from macrophages exposed to Ti-alloy and PMMA particles. Antibodies to MCP-1 and MIP-1α inhibited chemotactic activity of the culture medium samples. Release of C-C chemokines by macrophages in response to wear particles may contribute to chronic inflammation at the bone-implant interface in total joint arthroplasty.