Purpose: We conducted a retrospective study of 20 total elbow prostheses GUEPAR humerocubital and humeroradial (G3) implanted in 19 patients with rheumatoid arthritis. This anatomic metal-polyethylene prosthesis is available in a left and right model and in two sizes, large and small. A radial head prosthesis is now available in addition to the humerocubital prosthesis. The radial head prosthesis has an intramedullary metallic stem and a mobile polyethylene cup which comes in several sizes.

Material and methods: Among 20 prostheses implanted between 1997 and 2001, four were first-generation prostheses which did not have a radial head. At three to four years, these four prostheses developed valgus instability with deterioration of the polyethylene of the cubital piece requiring revision with a new generation GUEPAR associated with a radial head. This gave two good results and two failures revised with a semi-constrained prosthesis. For the 16 other cases of rheumatoid disease, the G3 humerocubital prosthesis associated with a radial head was inserted. These 16 prostheses were followed two years and were retained for this analysis. The posterior approach was used with inverted-V section of the triceps using the surgical technique recommended by the promoters. Patients had permanent severe to moderate pain. The Mayo Clinic score (1992 including daily life activities) was 33/100. Radiographically, seven elbows were Larsen grade III, nine grade IV, seven grade IIA and nine grade IIIb (Larsen classification modified by the Mayo Clinic).

Results: All patients were reviewed with mean follow-up of two years (1–5). The Mayo Clinic score improved from 33/100 to33/90 with outcome considered excellent in 15 elbows and fair in one.

Discussion: We recommend total elbow prostheses for rheumatoid arthritis patients. Semi-constrained prostheses have indications in certain cases of massive destruction, but the minimally or non-constrained gliding prostheses, such as the GUEPAR prosthesis, are part of the evolution of these prostheses, just as was the case for knee prostheses. These good results can be expected to persist over time.

Introduction: Dislocation after primary total knee arthroplasty is a very uncommon complication. Some case reports referred to Total Condylar, Insall Burstein or more recently Mobile bearing prostheses.

Frequency is probably under evaluated and their treatment and consequences subject to discussion.

Dislocation has to be differentiated from knee instability, subluxation and expulsion of the PE tibial insert.

The purpose of this review was to study their mechanism, treatment and consequences.

A modification of the surgical technique and the insert design was deduced.

Materials and methods: From 9/1994 to 9/1998, 229 primary Wallaby 2 with an original modular PE tibial insert were performed by the Guepar in 11 centers. Eleven posterior dislocations occurred less than 2 years postoperatively.

A prospective analysis was performed to compare the following variables of these patients (study group) to 56 cases who did not experience that complication (control group): age, sex, weight, component size, surgical approach, importance of release, pre and post surgical scores, alignment, stability, patella and component thickness. Statistical analysis of these parameters was performed.

Results: There were no statistical differences between the two groups for any variable assessed except importance of the valgus knee deformity (11° vs 6°), Keblish approach, lateral release and postoperative flexion (119° vs 106°) p< 0.01.

Conservative treatment was successful in 10 cases, but 3 recurrent dislocations and a neglected dislocation were treated surgically after modification of the tibial insert.

Discussion: Possible factors contributing to these dislocations are discussed as surgical procedure, quality of knee stability, characteristics of the tibial post compared to other implant (placement, dislocation safety factor).

After modifications of the stabilizer concerning height and slight posterior displacement, in a personal series of 129 TKA, dislocations disappeared.