BACKGROUND The study aimed to analyze the complications following cementless arthroplasty surgery where original sphericity was not obtained and screw-cap system was required. METHOD The study inclusion criteria were met by 39 patients aged 47 - 90 and the mean follow-up period was 54 months. Patients were operated in a lateral position, through the posterolateral or minimal posterior approach.To assess postoperative functionality, Harris Hip Score and Hoos questionnaire were applied. RESULTS According to the Harris Hip Score, 64.3% of the scores were very good and good and the mean score was 96 according to the Hoos questionnaire. The incision type, BMI and the type of cutaneous suture had no impact on the functional outcome, incidence of complications and a pain rate in the groin. Scar esthetics received highest scores from the patients operated through the minimal posterior approach and treated with a running intra-cutaneous suture. Yet a lateral position during the surgery made any intraoperative assessment of the limb length considerably more difficult. Consequently, 30% of the operated patients reported different limb lengths, which significantly (p = 0.036) lowered a functional outcome measured according to the HOOS and Harris Hip Score. The functional outcomes demonstrate a considerably negative correlation with age but not with gender although men are more vulnerable to the postoperative complications (p = 0.18). CONCLUSION Despite a relatively large number of complications following the surgery using a screw-cap system, 75% of the patients declared they would not mind another surgery using such system.

Background. The lack of ideal sphericity of the hip joint acetabular bed is a problem encountered by orthopedists during the initial process of learning about hip joint replacement procedures. The aim of the study was analysis of the complications after cementless endoprosthesoplasty, when the primary sphericity was not obtained and the “Screw Cup” acetabulum (Aesculap) was used as a rescue procedure. Material and methods. The inclusion criteria were met only by 39 patients since, due to numerous complications, such implants were no longer used for patients aged 44–90 years and the average time of postoperative observation was 54 months. The patients were operated in a lateral position, from the posterolateral access or minimally invasive posterior access. In order to assess hip joint function after the procedure, the Harris and Hoos Hip Score questionnaires were used. Results. Harris Hip Score revealed 64.3%very good and good results and the obtained mean score was 96 points according to Hoos’s questionnaire. The type of surgical incision, BMI values and the types of dermal sutures had no impact on the functional result, the rate of complications and the incidence of pain in the groin. All the pa­tients who underwent surgical procedures using the minimally invasive access and whose skin sewn using a transdermal continuous suture, assessed their postoperative scars as esthetic. However, the lateral position during the procedure significantly complicated the intraoperative limb length assessment. In consequence, 30% of the opera­ted patients reported different lengths of their lower limbs, which significantly (p = 0,036) reduced the score corresponding to limb functionality, measured using HOOS and Harris Hip Score. The functional values show a significantly negative correlation with age, but not with gender, although men are more at risk of postoperative complications (p = 0,18). Despite the relatively big number of postoperative complications after surgical procedures using the “Screw Cap” acetabular implants, 75% of patients operated using this approach reported no objections to secondary procedures using the same system. Conclusions. Using the Screw Cap” acetabular implants in cases of failure to obtain an ideal sphericity entails the risk of numerous complications and only 60% of the results are good and very good, therefore, the authors of this paper do not recommend this solution.