The Dual Articular Knee (Biomet®) is a modular revision prosthesis with a mobile bearing. We performed 24 operations on 23 patients: 16 female and 7 male patients. The average age at revision was 71.6 years, range 42–84 y, the average time span between primary TKR and revision was 8 years, range 1–19 y. The average follow up was 25 months, range 3–68 months.

Diagnoses at primary TKR were: Osteoarthritis 19, Rheumatoid arthritis 1, Post-traumatic arthrosis 2, s/a medial Unicondylar 1, s/a High Tibial Osteotomy 1.

Primary Implants were: Total Condylar (Howmedica) 4 (3 with metal trays and 1 all PE tibia); IB 2 (Zimmer) 9, IB 1 (Zimmer) 2, Miller Galante (Zimmer) 1, AGC (Biomet) 5, Sigma (J& J) 2, Sigma RP (J& J) 1.

Inciations for revision were:

Aseptic loosening and PE wear 20, Infection 4 (Organisms: MRSA 1, Enterococcus Faeconium 1, Streptococcus Gr.6 1, Negative Culture 1).

Surgical Technique: We used a medial parapatellar approach in 22 knees and the lateral parapatellar approach in 2 knees, osteotomy of the tibial tuberosity was performed in 16 operations and a lateral patellar release in 7. The patellar implant was replaced in 5 knees, left in situ in 4 and not replaced in 15 knees (one of the knees was after a previous patellectomy). Two stage revision was performed in 4 infected knees and in one non-infected. Cement spacers impregnated with antibiotics were used in 3 operations. Original implants as temporary implants with antibiotic loaded cement were used in 2 operations.

Results: Results were rated as good if the knee was stable with flexion of 90 degrees or more without evidence of infection and fair with less than 90 degrees of flexion.

Good results were obtained in 19 knees, fair in 2, failure due to late infection in one knee. One patient was lost for follow up, one patient died 6 months after surgery of an unrelated cause.

Conclusions: The Dual Articular Revision Prosthesis is a useful implant system in cases with satisfactory collateral ligament stability.

Between 1983 and 2001, 25 revision of total knee arthroplasties were performed in our department. 16 tibiofemoral, 9 tibial revisions and 9 operations on the patella were performed.

The original implants of the 16 tibio femoral revisions were 8 total condylar, 2-IB1, 2-IB2,

1 AGC, 1 cruciate retaining AGC and 2 porous coated J& J.

The revision prostheses were: One IB1, 1 kinematic II, 7 CCK, 4 dual articular, 1 sigma and 2 Guepar.

The results were: very good 2, good 9, failure 2 (sepsis, removal of implants and knee fusion), 3 patients died during the study period of unrelated causes to surgery. One of them was followed for 13 years, having a very good result (Kin II) until his death.

Tibial component revisions were performed on 9 knees.

The original implants were: 5 total condylar, 1 IB-1 and 3 IB-2.

The revision implants were: 5 total condylar, tibiae, 1 IB-1, 1 IB-2 and 2 IB-2 with augments and intramedul-lary rods.

The results for the tibial revisions were: good – 4, fair 1, failures – 2 (sepsis and eventually arthrodesis. Two patients died within the study period of unrelated causes.

The patella posed a special problem, of 9 patients, 7 were operated for patellar component loosening, and the component was removed. In one patient a patellec-tomy was performed because patellar osteomyelitis was suspected. In another patient a tibial tuberosity transfer for patellar dislocation was performed.

The results of patellar surgery were: 4 – fair, 1 – unknown, and 4 patients died during the study period of causes unrelated to surgery.

Our series reflects the gathered experience in our department. During the early years tibial and patellar loosening were the main problems. Special revision prostheses were not available and were not needed in most cases. Later, with increasing number of arthroplasties performed, and with longer follow up periods, the need for special revision prostheses became overt. The most commonly used implant was the constrained con-dylar knee and was later replaced by the dual articular prostheses. The latter appealed to us because of its partially mobile tibial articular surface.

Our failures were due to Staphylococcus aureus sepsis, which we were unable to eradicate, in spite of performing staged procedures, repeated joint debride-ments and the use of gentamycin impregnated bone cement.

In all but one of these cases the implants had to be removed and the knee had to be fused. In one of our 4 failures even after solid fusion, the infection was not eradicated. We succeeded to revise only one infected knee with Staph. Aureus with a good functional result. In one case of candida infection, we succeeded to eradicate the infection and replaced the loose implants with a CK achieving a good result now for 4 years.