[Treatment of Acute Periprosthetic Infections with DAIR (Debridement, Antibiotics and Implant Retention) - Success Rate and Risk Factors of Failure]. / Lécba akutních periprotetických infekcí postupem DAIR (debridement, antibiotics and implant retention) ­ úspesnost a rizikové faktory selhání.

PURPOSE OF THE STUDY Revision surgery with implant retention and exchange of mobile prosthetic parts is considered to be the method of first choice in acute periprosthetic infections with a stable endoprosthesis and good condition of soft tissues, where the symptoms did not last longer than 3 weeks. The aim of the study was to evaluate the long-term outcomes and to identify the factors affecting the success rate of this procedure. MATERIAL AND METHODS This unicentric retrospective study evaluated the results of 18 surgeries with implant retention performed at the Department of Orthopaedics of Ceské Budejovice Hospital in the period 2009-2016. The failure of the procedure was defined as the presence of at least one of the following criteria: removal or replacement of endoprosthesis within 2 years after the DAIR procedure, detection of the same pathogen during the DAIR procedure and in the later performed revision surgery, necessity of chronic suppressive antibiotic therapy, death related to periprosthetic infection. The cured patients were invited for a clinical check-up. The postoperative condition was assessed using the Knee Society Score and the Harris Hip Score. RESULTS The overall success rate of the procedure reached 61.1%. Hematogenic dissemination was the cause of periprosthetic infection in 13 followed-up cases (72.2%), with the average time after the implantation of 153.2 weeks. Treatment through the DAIR procedure was successful in 53.8%. Early postoperative complications were observed in 5 cases (27.8%), in 4 of which, i.e. 80%, they were successfully managed by a surgery with implant retention. The most frequently identified etiological agents were Staphylococcus aureus and Staphylococcus epidermidis strains. In primo-implanted endoprostheses the success rate reached 90.9% (in case of early postoperative infections even 100%), whereas surgeries in repeatedly operated joints were successful in 14.3% only. The mean value of the Knee Society Score in patients after a successful knee joint surgery was 81.2 of the maximum score of 100 (σ= 8.5), the Function Knee Society Score was 70 of 100 (σ= 34.6). In the case of the Harris Hip Score in patients after the hip replacement, the mean hip function score was 89.8 of the maximum of 100 (σ= 7.3). The patients with knee and hip joint endoprosthesis after the performed DAIR procedure were satisfied on average to the level of 82.5% and 90%, respectively, while 28.6% of patients experienced certain functional decline during daily activities. Postoperatively, 25% of patients reported continuing stronger pain as compared to the past medical history. No patient experienced any change in terms of a limited range of motion or decreased joint stability. DISCUSSION The overall success rate of the DAIR procedure of 61.1% corresponds with the values stated in the literature. A significantly higher success rate was achieved in early postoperative complications. This can be explained by a lower specificity in determining the actual pathogenesis of late periprosthetic infections and potentially longer lasting colonisation of endoprosthesis. The medical history of previous surgeries performed on the affected joints for septic arthritis or with a surgical instrument retention was identified as an important risk factor of failure of the subsequently performed DAIR procedure. Significant effects of pathogenicity of the detected agent or systemic comorbidities on the success rate of the procedure were not confirmed in our group. Successful performance of the DAIR procedure results in maintaining a very good function of endoprosthesis as well as subjective satisfaction of patients. CONCLUSIONS The DAIR technique is an ideal solution in correctly and early diagnosed acute periprosthetic infections. The results suggest that it is particularly appropriate in early postoperative infections of primary total joint replacements. Its indication in late periprosthetic infections, especially of repeatedly operated joints, shall be carefully considered. Key words:acute periprosthetic joint infections, PJI, DAIR, implant retention, risk factors, success rate.

[Use of Patient Specific Instruments at Total Knee Arthroplasty. One-Year Results of a Prospective Randomised Study]. / Pacient Specific Instruments (PSI) pri implantaci TEP kolenního kloubu - rocní výsledky prospektivní randomizované studie.

UNLABELLED: PURPOSE OF THE STUDY The aim of this prospective study was to evaluate, at one year of follow-up, radiographic and clinical results of total knee arthroplasty (TKA) performed with use of Zimmer® Patient Specific Instruments (PSIs) which allow for planning and customising each patient's TKA. MATERIAL AND METHODS Of the patients with knee arthritis who were eligible for joint replacement, 23 were randomly selected and included in this study. There were 11 men and 12 women, with 11 right and 12 left knee joints. On the basis of pre-operative CT scans, PSI custom-made pin guides, which conformed to the individual patient's anatomy, were produced and then used in the THA surgery involving a NexGen (CR) system. All patients were examined before surgery and at 1 year after THA. The evaluation at a follow-up visit included standing full-length radiographs (antero-posterior and lateral), Knee Score results, range of motion (ROM), patient's satisfaction report, and post-operative complications. The X-ray views were examined for mechanical leg axis alignment, TKA alignment in antero-posterior and lateral projection and signs of potential loosening. RESULTS At 1 post-operative year, the average Knee Society Score (KSS) was 85.5 points and the average functional score was 82.6 point. The satisfaction rate was 94% and, on a school rating system, the average mark was 1.3. The average postoperative ROM value was 116°. All patients were willing to undergo the surgery again. The only complication was thrombosis in one patient. Radiographic findings of knee alignment were optimal in 18, correct (up to 3° deviation) in three and incorrect (above 3° deviation) in two patients. Radiographic signs of loosening were not recorded. DISCUSSION Correct knee alignment is one of the requirements for achieving a good TKA outcome. Various techniques are used to improve the total knee process (computer-aided surgery, customised guides). Zimmer Patient Specific Instruments provide advanced pre-operative planning and more accurate implant sizing and alignment. An experienced surgeon can achieve the same good results with conventional planning under standard conditions but the use of PSIs is clearly more beneficial in patients with extra-articular deformities and in patients in whom femoral intramedullary guides cannot be employed. To produce a custom-made pin guide requires a CT scan of the whole leg and is also associated with additional paperwork. The PSIs simplify the total knee process from start to finish and surgeons have complete flexibility to make fine-tuning adjustments during the procedure. CONCLUSIONS Zimmer Patient Specific Instruments allow for exact alignment of both the femoral and the tibial component in a TKA process. Under standard circumstances, clinical and radiographic outcomes are comparable with those of conventional planning. However, the use of PSIs is clearly more beneficial in patients with extra-articular deformities and in patients in whom femoral intramedullary guides cannot be employed. KEY WORDS: total knee arthroplasty, TKA, Patient Specific Instruments, PSIs.