Reducion of friction between bearing surfaces in Total Hip Arthroplasty is a main target of biological tribology. MPC (2-Methacryloyloxyethyl phosphorylcholine) has a similar properties to those of cell membranes, and can reduce friction with fluid luburication. We have used crosslink polyethylene with MPC polymer coating for primary and revision THA since 2011. Eighty one cementless THA were performed with closslink polyethlene liner with MPC polymer in our hospital. We have examined 21 cases which were followed for more than one year. Eighteen cases for primary THA and three for revision THA, and 3 were male and 18 were female. Seventeen cases were osteoarthritis, two osteonecrosis of femoral head and two rheumatoid arthritis. Average age of patients at THA was 60.4 years old. In the OR, we have experienced a very wet and slippery feeling on the bearing surface of polyethylene liner every time. Surface touch is similar to skin with lotions. No wear were measured on the X-ray display and no infections and no fractures were occurred during follow up. MPC polymer coating in THA can be useful for reduction of friction and generation of wear debris.
The wrist is the ”key-stone” of hand function. Painless stability is a prerequisite for the rheumatoid wrist to perform various manual tasks. Synovectomy of the extensor tendons and the wrist joint with a Darrach procedure is offered for painful wrists, which are not controlled by conservative treatment with medication and orthosis. Radiolunate arthrodesis is performed on wrists with an unstable radiocarpal joint and preserved midcarpal joint space. This study describes the long-term (more than 10 years) follow-up of these operative procedures.
The follow-up study was performed on 25 wrists in 25 rheumatoid patients (22 women and 3 men), whose average age was 52 years (range, 33 to 66 years) with an average disease duration of 12 years (range, 1 to 38 years). The average follow-up period was 12. 5 years (range, 10 to 18 years). Five wrists were Larsen-Dale-Eek’s grade II, 14 were grade III, and 6 were grade IV. Depending on the severity of bone destruction, the scaphoid in 6 wrists and the triquetrum in 3 wrists were included in the fusion site.
Preoperative pain (88%) and swelling (96%) decreased remarkably at follow-up (12%, 4%). Average grip strength increased significantly from 100mmHg to 140mmHg (p<
0. 01). The total arc of wrist extension/ flexion decreased to two-thirds of the preoperative arc with a major loss in flexion (preop. : 26/28degrees, follow-up: 23/13degrees). The range of forearm rotation increased due to a Darrach procedure. In periodical X-ray assessments of 23 wrists, carpal collapse initially improved following the operation, however, it returned to the preoperative level after 5 years. Ulnar carpal shift improved significantly after the operation (p<
0. 01), and the position remained unchanged over 10 years. In palmar carpal subluxation, no remarkable change was noted. Bone union occurred in 87% of the operated wrists and the remaining 13% had fibrous union. Widening at the lunocapitate joint (>
2mm) was noted in 4 wrists (17%) and progressive instability at the midcarpal joint occurred in one wrist with the mutilating type of disease. Narrowing (<
1mm) was noted in 5 wrists (22%) and 3 wrists were totally fused in the functional position.
Radiolunate arthrodesis provides good stability with some motion for the moderately deteriorated rheumatoid wrist more than 10 years after the operation, in spite of some radiological progression of the disease. This operation is considered to convert the natural course of the rheumatoid wrist from the unstable form to the stable form.
The wrist is the ”key-stone” of hand function. Painless stability is a prerequisite for the rheumatoid wrist to perform various manual tasks. Synovectomy of the extensor tendons and the wrist joint with a Darrach procedure is offered for painful wrists, which are not controlled by conservative treatment with medication and orthosis. Radiolunate arthrodesis is performed on wrists with an unstable radiocarpal joint and preserved midcarpal joint space. This study describes the long-term (more than 10 years) follow-up of these operative procedures.
The follow-up study was performed on 25 wrists in 25 rheumatoid patients (22 women and 3 men), whose average age was 52 years (range, 33 to 66 years) with an average disease duration of 12 years (range, 1 to 38 years). The average follow-up period was 12. 5 years (range, 10 to 18 years). Five wrists were Larsen-Dale-Eek’s grade II, 14 were grade III, and 6 were grade IV. Depending on the severity of bone destruction, the scaphoid in 6 wrists and the triquetrum in 3 wrists were included in the fusion site.
Preoperative pain (88%) and swelling (96%) decreased remarkably at follow-up (12%, 4%). Average grip strength increased significantly from 100mmHg to 140mmHg (p<
0. 01). The total arc of wrist extension/ flexion decreased to two-thirds of the preoperative arc with a major loss in flexion (preop. : 26/28degrees, follow-up: 23/13degrees). The range of forearm rotation increased due to a Darrach procedure. In periodical X-ray assessments of 23 wrists, carpal collapse initially improved following the operation, however, it returned to the preoperative level after 5 years. Ulnar carpal shift improved significantly after the operation (p<
0. 01), and the position remained unchanged over 10 years. In palmar carpal subluxation, no remarkable change was noted. Bone union occurred in 87% of the operated wrists and the remaining 13% had fibrous union. Widening at the lunocapitate joint (>
2mm) was noted in 4 wrists (17%) and progressive instability at the midcarpal joint occurred in one wrist with the mutilating type of disease. Narrowing (<
1mm) was noted in 5 wrists (22%) and 3 wrists were totally fused in the functional position.
Radiolunate arthrodesis provides good stability with some motion for the moderately deteriorated rheumatoid wrist more than 10 years after the operation, in spite of some radiological progression of the disease. This operation is considered to convert the natural course of the rheumatoid wrist from the unstable form to the stable form.
Since 1981, we have used various types of the total hip prosthesis for the reconstruction of the acetabular protrusion in rheumatoid arthritis. The cemented Charnley prosthesis was used during the initial 8 years, and we experienced loosening of the cemented acetabular socket in some cases. The bipolar femoral head prosthesis, which started to be used from 1984, was one of the cementless prosthesis. And it showed high frequency of proximal migration of outerhead. The threaded socket also showed frequent loosening. To overcome these problems, we started to utilize a new method from 1988. This method included packing morselized bone grafts into the acetabulum and fix them using a porous coated socket and screws. This study describes the results of cementless total hip arthroplasty (THA) for the acetabular protrusion in rheumatoid arthritiswith this method.
Sixty -one cementless THAs with use of porous coated acetabular socket were performed in 50 patients who had sever protruded acetabulum due to rheumatoid arthritis. The average follow –up period was 9 years and 5 months (range, 5 to 13 years). A Mallory/ Head prosthesis with porous coated socket was used in 43 hips and other types in 18 hips. In all operated hips, autogenous morselized bones were grafted on the thin acetabullar wall.
The clinical improvement in pain was the most apparent. X-ray findings of the grafted bone in the acetabulum showed a homogenous pattern in most cases (90. 2%) at 6 months after the operation. A radiolucent zone at a non-weight-bearing area between the grafted bone and socket was seen in 20 hips (32. 7%) for 3 years after the operation, and it gradually disappeared and changed to a sclerotic zone. Collapse and /or absorption of the grafted bone were noted in 3 hips of the patients with sever osteoporosis and high disease activity.
There are several technical key points to succeed THA in patients with rheumatoid arthritis. The first is the selection of the acetabular socket. The second is the method of bone grafting, and the third is the size and the shape of grafted bones. We have used various types of prosthesis for the protruded acetabulum so far, and it was considered that the bipolar and threaded types are not acceptable because of their high frequency of proximal migration and loosening. The mass and /or block bone should not be used, because they are liable to fall into collapse. It is safely recommended to use slice or morselized bones to lead the grafts to early survival and remodelling caused by tight and close contacts.
THA with the use of morselized bone grafting into the acetabulum and a fixation with a porous coated socket-and screws is a simple and useful procedure for treating protruded acetabulum in rheumatoid arthritis.