Spontaneous osteonecrosis of the knee (SONK) mainly affects the medial femoral condyle, would be a good indication for UKA. The primary aim of this study was to assess the clinical, functional and radiographic outcomes at middle to long-term follow-up, of a consecutive series of fifty UKA used for the treatment of SONK. The secondary aim was to assess the volume of necrotic bone and determine if this influenced the outcome. We reviewed 50 knees who were treated for SONK. Patients included ten males and 38 females. The mean age was 73 years (range, 57 to 83 years). The mean height and body weight were, respectively 153 cm (141 ∼171 cm) and 57 kg (35 ∼75kg). All had been operated on using the Oxford mobile-bearing UKA (Zimmer-Biomet, Swindon, United Kingdom) with cement fixation. The mean follow-up period was 8.4 years (range, 4 to 15years). We measured the size (width, length and depth) and the volume to be estimated (width x length x depth) of the necrotic bone mass using MRI in T1-weighted images. The clinical results were evaluated using the Knee Society Scoring System (KSS) and Oxford Knee Score (OKS). The flexion angle of the knee was evaluated using lateral X-ray images in maximum flexion.Aims
Patients and Methods
To compare the effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament (ACL) reconstruction animal model. Anterior cruciate ligament reconstruction using the plantaris tendon as graft material was performed on both knees of 24 rabbits (48 knees) to mimic ACL reconstruction by two different suspensory fixation devices for graft fixation. For the adjustable fixation device model (Socket group; group S), a 5 mm deep socket was created in the lateral femoral condyle (LFC) of the right knee. For the fixed-loop model (Tunnel group; group T), a femoral tunnel penetrating the LFC was created in the left knee. Animals were sacrificed at four and eight weeks after surgery for histological evaluation and biomechanical testing.Objectives
Methods
The aim of this study was to investigate the effect of granulocyte-colony stimulating factor (G-CSF) on mesenchymal stem cell (MSC) proliferation MSCs from rabbits were cultured in a control medium and medium with G-CSF (low-dose: 4 μg, high-dose: 40 μg). At one, three, and five days after culturing, cells were counted. Differential potential of cultured cells were examined by stimulating them with a osteogenic, adipogenic and chondrogenic medium. A total of 30 rabbits were divided into three groups. The low-dose group (n = 10) received 10 μg/kg of G-CSF daily, the high-dose group (n = 10) received 50 μg/kg daily by subcutaneous injection for three days prior to creating cartilage defects. The control group (n = 10) was administered saline for three days. At 48 hours after the first injection, a 5.2 mm diameter cylindrical osteochondral defect was created in the femoral trochlea. At four and 12 weeks post-operatively, repaired tissue was evaluated macroscopically and microscopically.Objectives
Methods
Most Japanese patients who receive total hip arthroplasty (THA) are osteoarthritic and 70% have development dysplasia of the hip. Their stature is shorter than average and their sizes (acetabular cup and femoral stem) are smaller. The Taperloc Microplasty (BIOMET) is a short femoral stem. It was launched on July 2012 in Japan (extended on January 2013). It is essentially a shortened version of the Taperloc stem (35mm shorter than the standard stem). We aimed to evaluate the outcomes of minimally invasive anterolateral THA using a short stem.Introduction
Objectives
In recent years, an increasing number of reports related to adverse reactions to metal debris (ARMD) following metal-on-metal (MOM) total hip arthroplasty (THA) have been published. Some patients who experience ARMD require revision surgery. In this study, we aimed to evaluate the mid-term results of MOM THA.Introduction
Objectives
In February 2004, our institute began to perform routine cervical CT scans in addition to head CT examinations on patients with blunt head trauma who had received high energy injuries. We present the findings of 108 patients who underwent a routine cervical CT within the last year and the usefulness of routine cervical CT examinations is discussed. The present report is, to our knowledge, the only prospective study to examine the utility of routine cervical CT examinations. Among the patients admitted to the emergency room of our institute after receiving high energy injuries, 108 patients had blunt head trauma and underwent a routine cervical CT examination in addition to the head CT examination specified by our original protocol for cervical clearance. The mechanism of injury and the presence of cervical bone lesions were noted in each case. 76 males and 32 females ranging in age from 13 to 77 years (average, 41.0 years) were included in the study. Among these 108 cases, cervical fractures or subluxation were visible in 5 cases on plain films. Although no fractures were seen on the plain films taken in the remaining 103 cases, the additional cervical CT examinations demonstrated 14 cervical fractures in 13 (12.6%) of these cases. For patients with blunt head trauma, a cervical CT examination is not usually performed if no evidence of a cervical fracture is found on plain films and no neurological deficits are present. Nevertheless, the present findings suggest that many cervical fractures may have been missed on plain films in the past, and the routine inclusion of a cervical CT examination in addition to a head CT examination might be appropriate in the evaluation of patients with blunt head trauma who have been involved in a high energy injury.
We investigated the incidence of PE (Pulmonary Embolism)and DVT (Deep Vein Thrombosis) after THA by the use of MDCT (multi-detect or row CT scan). The purpose of this study was to evaluate the meaning of blood coagulation molecular markers (FDP D-dimer, Soluble Fibrin Monomer Complex) for the prospect of PE and DVT after THA. We studied 30 THA patients. There were 2 men and28 women. The value of D-dimer and SFMC before and after THA was examined. MDCT was carried out for DVT and PE investigation, in all cases 7 days after-THA. The relation between the values of blood coagulation molecular markers and existence of PE and DVT was evaluated. PE occurred in 2 cases and DVT in 4 cases out of 30 cases. D-dimer values of these 2 PE cases in 7 days after THA were higher (18,39), compared with average values (12). Among DVT 4 cases, in 1 case DVT existed on thigh and in other 3 cases existed on calf. The SF values in 7 days showed extremely higher in only thigh DVT case (99), compared with average values (16.6). The value of SFMC fell down rapidly in a few days, representing the biphasic property. MDCT is very effective for the diagnosis of PE and DVT. But it is difficult to make examination many times. It is very convenient to be able to evaluate PE and DVT by blood examination. From the results of this study, D-dimer may be sensitive for the diagnosis of PE and SFMC also may be useful for DVT. SFMC reacts more rapidly to abnormalities of thrombus and hemostasis. So it has possibilities to clarify the temporal responses of the DVT and PE more precisely.
Dislocation after total hip arthroplasty (THA) remains a significant clinical problem. The acetabular cup position is one of the main factors in the incidence of dislocation after THA. We reviewed dislocation cases in 247 primary THA Between 1997 and 2001, 247 patients underwent a primary THA procedure. The original diagnoses in these patients were as follows: osteoarthritis (OA, n = 190), osteonecrosis (ION, n=28), rheumatiod arthritis (RA, n=16), and rapidly destructive coxarthropathy (RDC, n=13). A posterolateral approach was used in all cases. We examined mainly the acetabular cup position (ante-version and inclination angle) using anteroposterior radiographs Six dislocations (2.4%) occurred : three anterior dislocations and three posterior dislocations. Dislocation rate according to the original diagnoses were as follows, 2 dislocations in OA (1.1%), 2 dislocations in RA(12.5%), 2 dislocations in RDC(15.4%) and no dislocation in ION. All cases were treated with close reduction and no component revision was needed. On X-P measurement of setting the acetabular cup in all cases, the mean ante-version angle was 16.3617;6.8 degrees and inclination angle was 43.3&
#61617;7.3 degrees. In comparison with these measurement values, there was no statistical difference between the dislocation groups and no-dislocation groups. The number of the cases within Lewinnek’s safe zone in acetabular cup was 178 (72%). The dislocation rate in these 178 cases was low (1.1%). Setting the acetabular cup in adequate position is one of the major factors avoiding dislocation after THA. We have been performimg computer - assisted THA since 2003. Computer - assisted surgery enables the acetabular cup position to be precisely planned before surgery and allows superior positioning during surgery.
Since the autumn of 2003, a computer-assisted system (VectorVision® Hip, version 2.1, Brain LAB, Germany) has been used to perform total hip arthroplasty (THA) operations in our hospital. In the present study, the postoperative acetabular cup position was evaluated using the records of the system and the data measured from postoperative radiographs. To date, 18 patients have been treated using this-system. We studied the cup inclination and anteversion records in this system recorded in the THA procedures. We also measured the cup inclination and anteversion using postoperative radiographs, according to the method described by Pradhan. The inclination and ante-version were the ‘operative’angles for this system and were the ‘radio graphical’ ones for measuring from the radiographs according to the definition described by Murray. The initial planning of the acetabular cup position was 45° ‘operative’ inclination and 20° ‘operative’ ante-version. From the system records, the average ‘operative’ inclination was 46.5°± 3.9° and the average ‘operative’ anteversion was 25.5°± 6.0°. The average ‘radio graphical’ inclination measured from the postoperative radiographs was 49.0°± 6.0°, and the average ‘radio graphical’ anteversion was 10.6°± 5.8°. Between the ‘operative’ angles from this system and the ‘radio graphical’ angles from the postoperative radiographs, the inclination was approximately the same, while the anteversion was different. When the ‘radio graphical’ anteversion was corrected for X-ray beam spreading and then converted to the ‘operative’ anteversion, the resulting ‘operative’ anteversion was 21.1°± 7.8°. And when the ‘operative’ anteversion recorded by this system was corrected for the pelvic tilt, the corrected ‘operative’ anteversion was 22.1°± 6.5°. The average difference between these corrected ‘operative’ anteversion in each case was 5.8°± 3.8°. Especially in 10 of the 18 cases, each difference was within 5°. The accuracy of the cup position using this computer-assisted system was shown by this study.
We evaluated the geometry of the resected femoral surface according to the theory for total knee arthroplasty (TKA) using three-dimensional computed tomography (3D CT). The 3D CT scans were performed in 44 knees indicated as requiring total knee arthroplasty. The 3D images of the femurs were clipped according to the following procedures. The distal femur was cut perpendicular to the mechanical axis at 10 mm proximal from the medial condyle. Rotational alignment was fixed at 3 degrees external rotation from the posterior condylar line. The anterior condyle was resected using the anterior cortex as the reference point. The posterior condyle was cut at 10 mm anterior from the medial posterior condyle. The medial-lateral (ML) width/anterior-posterior (AP) length was 1.58 ± 0.14 (mean ± SD). AP length of the 3D images tended to be longer than the box length of the three kinds of components provided when the ML width of the images was approximately equal to that of each component. The widths of medial and lateral posterior condyles of the images were 30.1 ± 3.8 mm and 24.8 ± 3.0 mm, respectively. In all except one case, the widths of the resected medial posterior condyles were greater than those of the medial condyles of all components when those of resected lateral posterior condyles were equal to those of the lateral condyles of the components. The shapes of the resected femoral surface did not always match those of the components. The configuration of Japanese knee joints is different from that of American knee joints. Components with appropriate geometry should be designed for Japanese patients.
The most considerable cause of nerve root damage are compression force and stretch force. Many researchers had reported about experimental study of the compression force, but it is difficult to find the report describing the stretch force to the nerve roots. The purpose of this study is to evaluate the physiological reaction of nerve roots of rats nuder stretch force. The nerve roots were prepared from the cauda equina of 8 Wister rats (weight: 300 – 400g). We investigated the changes in threshold and action potential of the nerve roots under stretch force and compression force. The threshold of the nerve roots increased and action potential decreased in parallel with stretch force. Also, the threshold and action potential recovered after releasing the stretch force. On the other hand, by compression force, the action potential decreased parallel with compression force, but the threshold did not change with compression force. Ten minutes after releasing compression force, the action potential did not recover as much as before, and the threshold increased rather than control. The different physiological reactions that occurred between compression force and stretch force are hard to explain by circulation insufficiency, as previously reported (hypoxemia and lack of nutrition). We considered that the etiology of the stretch force might be a change in internal pressure of nerve roots and a structural change in nerve cells. The physiological reaction of the nerve root under stretch force differed from that under compression force and recovered from the damage after release from stretch force.
