[Treatment of Periprosthetic Distal Femoral Fractures]. / Lécení periprotetických zlomenin distálního femuru.

PURPOSE OF THE STUDY Periprosthetic distal femoral fractures (PDFF) constitute an unpleasant complication in patients with a total knee replacement (TKR). The incidence reported in literature is 0.3-2.5 %. The number of periprosthetic knee fractures has been increasing due to the ageing of population, a growing number of implants, a longer life expectancy of patients, a more intensive physical activity of patients, and osteoporosis. Most of these fractures are treated surgically, non-surgical treatment is reserved solely for patients unable to undergo a surgery for general health conditions. MATERIAL AND METHODS Our retrospective study evaluated the group of patients with PDFF who were treated at out department in the period 2007- 2016 and 2,975 primary TKR were performed. The total number of patients with PDFF was 56. The mean age of patients with PDFF was 77 years (56-94 years) and at the time of fracture the mean age was 71 years in men and 78 years in women. The average time from the TKR to periprosthetic fracture was 8.2 years (0-20 years). The fractures were assessed using the Su classification modified by Krbec. RESULTS A primary TKR was performed in 46 cases for gonarthrosis, in 6 cases for rheumatoid arthritis and in 4 cases for secondary, post-traumatic gonarthrosis. The average incidence of periprosthetic distal femoral fractures was 5-6 cases per year. Women represented 86 %, men 14 %. Su Type I fracture was diagnosed in 25 % of cases, Su Type II fractures in 71 %, and Su Type III fractures 4 %. 52 patients with PDFF were treated surgically, in 4 cases conservative treatment was opted for. The average treatment time of PDFF to healing by callus formation was 6.6 months (3-12 months). Mortality during the first 3 months after osteosynthesis of PDFF was 9 %. A failure of osteosynthesis of PDFF was reported in 4 cases. DISCUSSION Multiple classification systems were developed to assess these fractures. The most appropriate we consider the classification of Su et al. classifying the PDFF into 3 groups, namely based on the height of the fracture line relative to the femoral component. Osteosynthesis by retrograde femoral nail is indicated for periprosthetic fractures, with sufficient bone mass in distal femur, which allows stable distal fixation. The new generation of anatomically shaped angular stable implants gives us yet another option for osteosynthesis of PDFF. Many studies point at the advantages of these implants in osteoporotic bone as against the conventional plates. CONCLUSIONS The number of PDFF has been increasing. The main methods of internal osteosynthesis continue to be the angular stable plates and the retrograde femoral nail. Preoperative planning is important to determine the type and dimensions of the existing femoral component and to distinguish whether or not it has come loose. The choice of the implant may depend on the bone mass available for distal fixation. The retrograde femoral nail is usually the most suitable method of treatment for proximal PDFF (Su Type I). The angular stable plates can be used for PDFF originating at the femoral component (Su Type II and Type III). Very distal fractures classified as Su Type III with a loose femoral component require a revision surgery with a TKR with stems. The surgeon should be prepared for a revision surgery if the intraoperative finding is more complicated than anticipated based on the preoperative radiograph. Key words:total knee arthroplasty, periprosthetic fracture, osteosynthesis.

[Minimally invasive stabilization of posterior pelvic ring injuries with a transiliac internal fixator and two iliosacral screws: comparison of outcome]. / Miniinvazivní stabilizace poranení zadního pánevního segmentu transiliakálním vnitrním fiátorem a dvema iliosakrálními srouby: srovnání funkcních výsledku

PURPOSE OF THE STUDY: A comparison of radiological and clinical results between dorsal pelvic segment stabilization with a transiliac internal fixator (TIFI) and that with two iliosacral screws (IS). MATERIAL AND METHODS: In this prospective study, both the TIFI and the IS group had 32 patients. The majority of injuries were assessed as type C1.3 because only patients with a high-energy mechanism of injury were included. Radiological results were evaluated according to the Matta scoring system and clinical outcome using the Majeed score and the Pelvic Outcome Score. Categorical data were evaluated by the two-sided Fisher's exact test or Pearson's χ2 test and continuous data by Student's t-test. A test result with p<0.05 was considered statistically significant. RESULTS: In the TIFI group, the mean posterior displacement was 2.2 mm, in the IS group it was 1.9 mm (p=0.58542). The pelvic outcome scores in the TIFI group were: excellent, 28%; good, 12%; fair, 48.0%; and poor, 4 %; in the IS group they were: excellent, 11.1%; good, 22.2%; fair, 66.7%; and poor, 0.0% (p=0.51731). The Majeed scores were as follows: excellent, 56.0%; good, 16.0%; fair, 20.0%; poor 8.0 % for the TIFI group and excellent, 50.0%; good, 27.8%; fair, 11.1%; and poor, 11.1% for the IS group (p=0.70187). Within the total, average Majeed score was 80.64 points in TIFI, 80.67 in IS (p=0.99654). In a sub-analysis of unilateral transforaminal fractures (Pohlemann type II), the average score for TIFI was 82.8 points and only 53.5 points for IS; the differences were statistically significant (p=0.04517). No intraoperative complications were associated with TIFI and one injury to the superior gluteal artery (3.1%) and two iatrogenic neurological injuries with IS (6.3%; p=0.23810). In the TIFI group, the fixator was removed without complications. In the IS group, post-operative wound bleeding following screw removal occurred in three patients (20.0%; p=0.22414), complete extraction of screws and washers was successful only in seven patients (46.7%), washers were left in situ in six patients (40.0 %) and IS removal was not possible in two patients (13.3%). The difference in complications between the groups was highly significant (p=0.00220). DISCUSSION: The results of our study are in agreement with those of the relevant studies published recently as well as with the outcomes of transiliac plate fixation reported in the literature. TIFI implantation is preferred in transforaminal and central sacral fractures because, unlike iliosacral screws, it carries a low risk of excessive compression of the sacral foramina and iatrogenic neurological injury. There were no significant differences in clinical and radiological findings between TIFI and IS procedures. Only in unilateral transforaminal fracture the TIFI stabilization had better outcome, as shown by the Majeed score. The IS fixation was associated with a higher rate of complications not only in primary implantation, but also at implant removal. CONCLUSIONS: The TIFI technique is superior to the IS procedure in fixation of unilateral transforaminal fractures and provides a reasonable alternative to the existing types of minimally invasive fixation.