Stemless hip prosthesis: notes of surgical technique

Introduction The concept of minimally invasive hip replacement is based on the use of stemless prostheses and the use of surgical techniques with limited bone loss and maximum respect of the soft tissues. Aim of the study Evaluate the average bleeding related to the time of surgery and the correct positioning between two minimally invasive hip implants. Materials and methods We evaluated 41 patients, mean age 74 years, affected by primary hip osteoarthritis treated with stemless prosthetic implant. In 21 patients a Proxima (De-Puy-J & J) hip prosthesis was used, while in the remaining 20 one other stemless implant (Parva-Adler) was used. All surgeries were performed by the same surgeon. Patients were evaluated by blood count preoperatively and in the immediate postoperative period. The evaluation of the correct positioning of the implant was calculated by the radiographic cervico-diaphyseal angle. In all the cases, the duration of the procedure was registered (end-incision procedure) and evaluated in comparison with 19 cases of traditional stems surgeries (Synergy-S & N, Stryker ABG-, Mercurius-Adler). Results In patients treated with Proxima operative time was approximately 153 minutes, while in patients treated with Parva it was 140 minutes. The average time for the long stems was 142 minutes. The decrease in hemoglobin was 3.49 g / dl for Proxima, and 2.86 g / dl for the Parva. In 11 of 21 patients treated with Proxima, cervical diaphyseal angle appeared slightly valgus (> 130 °), in the remaining corresponded to 130 °. In patients treated with Parva, 11 were considered to have a slightly valgus angle. No varus was found. Discussion and Conclusions The minimally invasive techniques are proving to be of great success. Stemless hip prosthesis allow, limited bone sacrifice. The disadvantages are represented by a greater operative time , and a longer learning curve. Our study showed that surgical time was not statistically different between long stems and stemless prostheses, in experienced hands . Among the various minimally invasive stems studied , Parva ( Adler) showed fewer surgical time ( <13 min.) and blood loss (< 0.60 g / dl). Both stems were " respectful " of the anatomical cervical diaphyseal angle ensuring proper biomechanics and load distribution . In conclusion, the implantation of hip stemless prostheses with minimally invasive technique , allows a correct positioning in a surgical time comparable to traditional stems . Differences between the two stemless implants (surgical time and blood loss) are related to the instrumentation and to the particular type of system , which results D in greater surgical complexity and a higher learning curve. In both cases, the conservative approach and the bone sparing , represent a real advantage , such as to justify their use .