Aim of the study: In order to compare the short-term results of a mini-incision in primary hip replacement with the results of the standard incision we developed a prospective study with 80 patients. Forty of them had a hip replacement using a mini-incision technique, and the 40 remaining patients using a classic approach.

Methods: All the patients were treated with an anatomic non cemented stem (ABG-II, Striker). No statistical differences were found related to age, gender and weight between groups. The patients were distributed into two surgical teams according to the date of their first visit to our service. Each team develop only one kind of procedure.

Results: No differences were found related to the incidence of surgical or postoperative complications, placement of the implants and need of early rehabilitation. Patients having a mini incision were discharged from the hospital only 1 day earlier than those having a standard incision (5.6 days vs. 6.7 days). Only blood transfusion showed a significant improvement: 8% in the mini-incision group and 32% in the standard approach needed a transfusion.

Conclusions: No major improvements were found related to the use of mini-incisions in primary hip replacement. To obtain the positive clinical outcomes related to this new technique some improvements should be done in anesthetics, pain control an early rehabilitation in selected and motivated patients.

Aims: To compare the vastus muscle-splitting approach and the classical medial parapatellar in total knee replacement. Methods: Prospective clinical and radiographic study in 50 cemented cruciate-retaining prostheses (Interax, Stryker-Howmedica-Osteonics): midvastus approach in 25 and parapatellar medial in 25. Results: There were no differences (p> 0.05) in postoperative femoro-tibial or patelar tilt angles, duration of surgery, drainage bleeding, Hemoglobine and Hematocrite at postoperative day 3, units of blood transfused, complications, hospital stay, range of motion, and score of the American Knee Society at 1, 6, 12 or 24 months. However, the midvastus approach showed less intraoperative lateral retinacular releases, more patients were able to get independent terminal knee extension at postoperative day 5, and the range of motion at discharge was higher (p< 0.05). Conclusions: The midvastus splitting approach can reduce the need to perform lateral retinacular releases, with advantages in the early postoperative range of motion and knee extension ability.

Aims: Clinical and radiographic comparison between a fixed polyethylene prostheses and mobile bearing design. Methods: Prospective study in 147 tricompartimental cemented cruciate-retaining prostheses (Interax, Stryker- Howmedica-Osteonics): 90 conventional fixed polyethylene and 57 mobile bearing (antero-posterior slide and rotation over an axis in the medial plateau). No differences in preoperative age, sex, range of motion, deformity, rheumatoid arthritis or osteo-arthritis, and Ahlback stage. Results: At 1, 6, 12 and 24 months there were no differences between both groups (p> 0.05) in femorotibial angles, radiolucencies, duration of surgery, pain at rest or walking, stairs, arise from chair, walking ability, range of motion, supports (cane or crutches), complications and score of the American Knee Society. Conclusions: With 2-year follow-up there are no differences in clinical or radiographic results between fixed and mobile bearing knee prostheses. Further investigations with long-time follow-up are mandatory in order to determine differences and advantages in polyethylene wear or implant survival.