Abstract
Unicompartmental knee prosthesis (UKP) has been used for 40 years but it is still controversial. Nevertheless, this procedure is positive and it can be a good alternative if it is correctly indicated.
From January 2001 we implanted 51 UKP in 47 patients. The diagnoses were: primary arthritis in 45 cases, post-traumatic degeneration in five and arthritis secondary to meniscectomy and ACL reconstruction in one. The mean age was 64.5 (range 49–81), 32 women and 15 men. Mean follow-up was 26 months (range 6–36). Post-operative recovery starts with physical rehabilitation, rarely with kinetics, and full weight-bearing walking the first day. DVT is prevented by treatment with low-molecular-weight heparin for 25 days and elastic stockings. From September 2002 we performed this procedure by minimally invasive surgery with an 8-cm incision and extramedullary intraoperative tools. We did not observe any infections or loosening: we performed just one revision of the femoral component because of a technical error. In four other cases a malpositioning of the femoral component was reported that was pain-free at follow-up.
Current studies are starting to show valid and encouraging results at mid- and long-term follow-up, too. The best candidates for UKP are patients over 60 years who are not overweight, with asymptomatic patellar degeneration and no anterior instability and who perform light sport activity. In comparison with high tibial osteotomy (HTO), UKP shows some advantages, such as faster recovery and better mid-term results. In comparison with total knee arthroplasty (TKA), UKP gives better range of motion, faster postoperative recovery and an easier operation in case of infection or loosening. Some features should be evaluated and the surgical technique should employ state-of-the-art hardware. We evaluate the advantages of this procedure with particular emphasis on the minimally invasive technique.
In conclusion, although our study is still in progress, correct patient selection, the surgical technique and the updated design of the new prosthesis can give satisfactory results and represent a valid alternative to HTO and TKA. In addition, compared to TKA, UKP shows a real economic advantage.
