Unicompartmental Knee Prosthesis Research Articles

Prothèse unicompartimentale — Soins post-opératoires et rééducation

This work reports postoperative and rehabilitation care provided by 11 teams-the same who attended the round table conference on “Unicompartmental knee prostheses”-. Drug prescription: An anticoagulant is prescribed for 10 days to 3 weeks. A preoperative perfusion of heparin is performed in the operated limb by one team -provided there is a pneumatic tourniquet (the rate of postoperative phlebitis has gone down from 50 to 6%). A course of antiflammatory and antalgic treatment is instituted by infusion for a few days and after this period, at the request of the patient. Postoperative splints: They are widely used. They have an antalgic role (for a 3 to 5 days period). Return to walking can be promoted. The use of postoperative splints must be limited since leads to a limited range of flexion and a loss of function schema. Elastic retention: They are used in two-third of cases. Weight-bearing: On the 2nd or 3rd day, instructions for weight-bearing are as follows:- bearing as completely as possible, - bearing 1/10 to 1/3 of body weight, - taking into account liabilities specific for each individual. Car driving is allowed since crutchers are no longer necessary. Range of knee motion: The goal is to achieve a range of 90° on the 21st day. Rehabilitation program: The selection of techniques will depend upon the clinical progress. Firstly, rehabilitation will be supervised by an independent physiotherapist in clinic and then in his private consulting room. This type of patient is seldom referred to rehabilitation centers. Recovery of strength will occur on weight-bearing and will be promoted by excitomotor electrotherapy. Physiotherapists will promote gait training, proprioception and return to previous function. Risks of complications include stiffness and loss of motor power. An early return to walking and normal function combined with an appropriate rehabilitation program should optimize surgical results.

Introduction — Questions posées

The purpose of this panel discussion is to answer the questions raised in 1994 about the indications for unicompartmental knee prostheses, and about the technique and results of this type of arthroplasty. Indeed, the subject of unicompartmental knee arthroplasty is one of the most controversial. In the light of French and foreign work, as well as series published by the members of the panel, it may be emphasized that any series published before 1980 cannot be compared with those published between 1980 and 1990: improved operative techniques and better selection of indications have largely contributed towards the improvement of results, although there is still a fairly high failure rate in the long term. The difficulty in evaluating results and the lack of standardized scores make it difficult to evaluate the exact failure rate, which varies from 6 to 25% depending on the author. The use of a standard system for evaluating results and the plotting of survival curves should, however, help to find comparable results in future years. The participants were asked to answer a number of questions. The answers to these questions should help each surgeon make a better selection of indications, use prostheses with optimum technology, and therefore improve his results. We hope these aims can be acheived and if they are, this GECO 1994 panel discussion on unicompartmental arthroplasty will have been successful.

Revision technique for failed unicompartmental knee arthroplasty

The main objective is to fit a total tricompartmental knee prosthesis. Conserving the ligaments and preserving the healthy bone are therefore the two main requirements. The surgical approach is, in most cases, parapatellar anteriorly and medially except in certain specific cases (lateral UKA). Total synovectomy is always necessary. The condition of the posterior cruciate ligament (PCL) should be evaluated with great precision, as this will indicate the type of revision prosthesis to be used. Bone cuts will be performed with the unicompartmental prosthesis in place. Bone grafts or filling blocks are rarely used; they are most often used in revising cemented unicompartmental knee prostheses.

The importance of sliding moment which is caused by implantatlon errors in unicompartmontal knee prosthesls

In this study, we evaluated the results of sliding type unicompartmental knee prosthesis whichwas performedat Holzminden Protestan Hospitalbetween April1,1987 and May 31,1993. We have performed 95 knee prostheses in 83 patients. 80 female, 3 male patients with the mean age of 71 constitute our material. Mean fo1low up period was 41 months (Ranged 4 months to 120 months). On conclusion sliding type unicompartmental knee prosthesis is a safe method in the treatment of gonarthrosis. Implantation errors compromise long term results. A tibial component placed in properly increase the load on cruciate ligaments.

Revision of Failed Unicompartmental Total Knee Arthroplasty

Forty-eight revision total knee arthroplasties (TKAs) for failed unicompartmental total knee prostheses were evaluated at 5.4 +/- 2.5 years after revision. The most frequent mode of failure of the original arthroplasty was loosening. All revisions used a condylar-type prosthesis. Fifty percent of the knees had bone defects that were filled with cement. Good or excellent results were achieved in 81% of the knees. One knee had a complete radiolucent line adjacent to the tibia at last evaluation. The surgical complication rate was 13%. Predictable salvage of the failed unicompartmental TKA can be achieved by revision arthroplasty.

Polyethylene wear of metal-backed tibial components in total and unicompartmental knee prostheses

We examined 86 polyethylene inserts, retrieved from total and unicompartmental knee prostheses after an average of 39.5 months in situ, grading them from 0 to 3 for seven modes of polyethylene degradation. Severe wear, with delamination or deformation, was observed in 51% of the implants, and was associated with time in situ, lack of congruency, thin polyethylene, third-body wear debris, and heat-pressed polyethylene. Significant under-surface cold flow was identified in some areas of unsupported polyethylene, and was associated with delamination in the load-bearing areas of thin inserts above screw holes in the underlying metal tray. We recommend the use of thicker polyethylene inserts, particularly in young, active patients and in designs with screw holes in the tibial baseplate. Thin polyethylene inserts which are at risk for accelerated wear and premature failure should be monitored radiographically at annual intervals.

Polyethylene failure in a PCA unicompartmental knee prosthesis

Polyethylene failure in a PCA unicompartmental knee prosthesis

Unicompartmental knee arthroplasty: A 4.5–6-year follow-up study with a metal-backed tibial component

The results in the first 50 patients to receive an improved-design unicompartmental knee prosthesis were reviewed after an average follow-up period of 5.5 years. The prosthesis is composed of a metal-backed polyethylene tibial component and a wide femoral surface replacement that are fixed to bone with acrylic cement. Forty-five patients with 55 unicompartmental knee arthroplasties were available for clinical study. Ninety-two percent of the knees were rated as having a good or excellent result, and 94% had lasting relief of pain. There have been no failures requiring revision. A radiographic review demonstrated that no tibial component was bordered by a complete radiolucent line. There was no subsidence or loosening of either the tibial or femoral components, and there was no instance of local osteolysis. These results, coupled with a 14-year follow-up experience with the original-design unicondylar prosthesis, encourages the authors to remain advocates of this procedure in selected patients with unicompartmental osteoarthritis

GUEPAR Unicompartmental Lotus Prosthesis for Single-Compartment Femorotibial Arthrosis

The results of 52 Groupe d'utilisation et d'expérimentation des prosthèses articulaires (GUEPAR) unicompartmental Lotus knee prostheses implanted for osteoarthritis of the knee are analyzed with a follow-up time exceeding five years (five to nine years). Thirty-five knees had no weight-bearing pain, six knees had slight pain, three knees had moderate pain, and eight knees had revisions. Except for one complication from infection, all the poor results (eight revisions and three knees with moderate pain) in terms of pain can be explained by mechanical causes, i.e., femorotibial subluxation, loosening of the tibial component, or narrowing of the nonprosthetic femorotibial space. Because the cause of these poor results appears to be due to malposition of the prosthesis component, or to components that are too thick with an inadequate mechanical axis, the precision of the surgical procedure is important.

Unicompartmental Knee Arthroplasty

This is a review of the results of 17 knees treated by modular-type (Marmor) unicompartmental knee prostheses. The average age at the time of the operation was 62 years with an average follow-up period of 59 months. All the patients improved and were satisfied with the operation. There were no cases of revision or degenerative changes in the opposite compartment. It seems clear that the indications for this procedure should be an elderly person with severe pain and single-compartment disease. The knee should have a correctable deformity with good range of motion, minimal flexion contracture, and good quadriceps strength.