PURPOSE OF THE STUDY The purpose of the study is to verify the correct alignment of components of the Oxford medial unicompartmental knee arthroplasty using the Zimmer Microplasty® instrumentation at the beginning of the learning curve. The implantation of prosthetic components of partial knee arthroplasty in proper alignment has an effect on long-term survival of the prosthesis and should eliminate the occurrence of frequent complications. MATERIAL AND METHODS The study group includes 20 patients, 9 men with the mean age of 68 years (range 62-78 years) and 11 women with the mean age of 69 years (range 52-81 years). 13 patients underwent surgery on the right knee and 7 patients on the left knee. The mean length of symptoms was 13 months (range 7-20 months), the mean varus knee deformity was 7° (range 4-12°). The selected patients met both the clinical and radiological criteria for enrolment in the study. In all of them medial unicompartmental knee arthroplasty was performed in 2019 by the same surgeon. After surgery, the parameters of accuracy of alignment of individual prosthetic components were measured on the full-length radiograph of the limb under load. The WOMAC score was recorded preoperatively and one year after surgery and subsequently compared. The knee joint flexion preoperatively and one year after surgery was evaluated. RESULTS The analysis of radiographs revealed that in 12 cases the femoral component was implanted in the mean valgus angle of 1.6° (range 1-3°) and in 8 cases in the mean varus angle of 3° (range 1-5°). All femoral components were implanted in the mean flexion of 7.3° (range 3-11°), no component was implanted in extension. As concerns the tibial component, 19 components were implanted in a neutral or minimum varus angle with the mean value of 1.1° (range 0.3-4°). One component only was implanted in the valgus angle of 1°. All tibial components were implanted with the mean dorsal slope of 6.5° (range 4-8°). The incision was 5 mm deep on average (range 3-6 mm). There was a slight divergence between the components, namely 2.8° on average (range 2-7°) and the distance between the components was 4mm on average (range 3-5 mm). The mean knee joint flexion achieved preoperatively by patients was 115° (range 110-123°), whereas postoperatively the mean flexion achieved was 126° (range 111-138°). The preoperative Womac score was 84.5 points on average (range 64-96 points), whereas postoperatively it was 26.4 points on average (range 7-52 points). None of the components was implanted outside the permitted range, no early complications of the partial replacement (luxation of polyethylene mobile bearing insert, early loosening of the prosthesis, tibial fracture) were observed. DISCUSSION Our radiographic measurements show that when Zimmer Microplasty® instrumentation is used correct alignment of the femoral and tibial component can be achieved and the individual components were correctly aligned within the recommended range. Every single component met the required criteria for alignment. When comparing the values obtained by us in measurements with those obtained by other authors from abroad, similar results regarding the alignment of components were achieved. CONCLUSIONS When using Zimmer Microplasty® instrumentation, excellent results can be achieved also at the beginning of the learning curve of partial knee replacement. Key words: medial gonarthrosis, unicompartmental arthroplasty, hemiarthroplasty, alignment of components.
- MeSH
- artróza kolenních kloubů * diagnostické zobrazování chirurgie MeSH
- femur diagnostické zobrazování chirurgie MeSH
- kolenní kloub diagnostické zobrazování chirurgie MeSH
- lidé středního věku MeSH
- lidé MeSH
- protézy kolene * MeSH
- senioři MeSH
- totální endoprotéza kolene * škodlivé účinky MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE OF THE STUDY Tantallum trabecular metal implants (Trabecular Metal Technology - TMT) considerably changed the acetabular reconstruction options in revision surgeries with extensive bone defects and distorted pelvic ring integrity. The purpose of this study is to ascertain the short-term to medium-term outcomes of acetabular reconstruction through TMT implants in patients with Paprosky type 3a and 3b acetabular defects and in case of pelvic discontinuity. MATERIAL AND METHODS The prospective monocentric study included patients in whom the revision of acetabular components in total hip arthroplasty was performed, the acetabular defect was classified as Paprosky 3a and higher, a TMT implant was used for reconstruction, and the follow-up period was at least 2 years after surgery. In total, 87 patients who had met the inclusion criteria were operated on and followed-up. The patients in the study group underwent a clinical examination, an X-ray and also an assessment using the Harris hip score. Moreover, the patients were asked about their satisfaction with the surgical outcome, their willingness to undergo the same procedure again in case of difficulties, and they were also asked to rate the outcome in percentage term and by assigning grades. Also, an analysis of the reasons for revision and subsequent complications was carried out. Implant integration and its migration were evaluated on an X-ray. RESULTS 32 men and 55 women were subjects to evaluation, with a balanced number of operated sides (44:43 in favour of the right side). One-stage procedures prevailed, which were performed in a total of 74 cases, while two-stage revisions were performed in 13 cases in the study group. In three patients (3.5%) pelvic discontinuity was diagnosed, 69 patients (79%) suffered from Paprosky 3a defect and 15 patients (17%) from Paprosky 3b defect. The first patients underwent surgery in 2009 and the mean follow-up period in the study group was 48 months. In 1 patient the TMT implant was removed for infectious complications, in the remaining part of the group the TMT implant was fully integrated with no signs of loosening or migration in the monitored period. In the assessment using the Harris hip score, the mean score of 80.4 (range 36-99) was achieved. When assessing the satisfaction with the surgical outcome, the mean value achieved was 94.4%, and the mean assigned grade was 1.26 (on a school grading scale). DISCUSSION Extensive bone defects and pelvic discontinuity represent an issue in revisions of the acetabular component in total hip arthroplasty. There are several options how to address these conditions. State-of-the-art TMT implants thanks to their shortterm and medium-term outcomes appear as one of the most beneficial option with a low failure rate both in our study group and in published papers. CONCLUSIONS Evaluation of this monocentric prospective study reveals encouraging short-term and medium-term outcomes of the use of TMT implants in managing extensive acetabular bone defects of Paprosky 3a and 3b type and supports their further introduction into practice at our department. Key words: total hip arthroplasty (THA), revision implantation, TMT implant.
- MeSH
- acetabulum diagnostické zobrazování chirurgie MeSH
- kyčelní protézy * škodlivé účinky MeSH
- lidé MeSH
- náhrada kyčelního kloubu * škodlivé účinky MeSH
- následné studie MeSH
- prospektivní studie MeSH
- protézy - design MeSH
- reoperace MeSH
- retrospektivní studie MeSH
- selhání protézy MeSH
- tantal MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
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.
- MeSH
- artritida diagnostické zobrazování chirurgie MeSH
- kolenní kloub diagnostické zobrazování chirurgie MeSH
- lidé MeSH
- následné studie MeSH
- počítačová rentgenová tomografie MeSH
- prospektivní studie MeSH
- totální endoprotéza kolene přístrojové vybavení metody MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
To present a prospective evaluation of one-year results in 162 patients undergoing total hip arthroplasty from a minimally invasive antero-lateral approach (THA MIS-AL). MATERIAL: A total of 249 THA MIS-AL procedures were performed between January 2005 and October 2007. At one year after surgery 162 patients were examined and their conditions evaluated by the Harris score, percent satisfaction assessment, 1-to-5 scale school marking, findings on lateral X-ray images and occurrence of post-operative complications. METHODS: With the patient lying in a lateral recumbent position, access is gained through a short incision (5 to 8 cm) along a line connecting the greater trochanter and the anterior superior iliac spine, between the gluteus medius and tensor fasciae latae muscles. After the articular capsule is removed and neck osteotomy done by a two-step procedures, the head is extracted. Both the acetabulum and the femur are processed with special instruments and a cemented or a cementless implant is inserted. Standard prophylaxis with antibiotics and anticoagulants is administered. The patient is mobilized from the second post-operative day, with individually allowed, partial weight-bearing of the operated extremity. RESULTS: In the 162 evaluated patients, the average Harris score increased from pre-operative 46.8 to post-operative 90.4 points. Excellent and good outcomes were found in 84% of the patients. The average school marking was 1.12 and patient satisfaction expressed in percent was 97%. Of 32 patients who had undergone both standard and minimally invasive hip replacement surgery, 25 considered the MIS AL technique to be better, five found no difference and two regarded is as worse. In two patients (0.8%), exposure had to be extended by the standard antero-lateral approach because of femur damage without displacement.Two patients (0.8%) suffered temporary post-operative peroneal nerve paresis. One patient (0.4%) had functional complications and five (2%) had to undergo surgery for haematoma. Sockets in a position other than the optimal 35 degrees to 55 degrees were recorded in two patients. The stem showed a 5 degrees varus deviation in one patient and that of 4 degrees in eight patients; a 4 degrees valgus deformity was found in three patients. Para-articular ossifications (stage 1 or 2) not affecting joint function were recorded in 20 patients (12%). DISCUSSION: Our results show good subjective evaluation of this technique. Its advantages include less pain and earlier patient mobilization. In our first patients a higher number of slight stem malposition (up to 3 degrees) was recorded. Early complications were rare. The occurrence of paraarticular ossifications was an unexpected finding; these, however, did not influence either joint function or subjective evaluation of the outcome. CONCLUSION: If all indication criteria are met and the operative technique is well mastered, the MIS-AL procedure helps provide successful outcomes with less muscle damage and more rapid rehabilitation for people receiving hip replacement; it has few complications and, in indicated cases, it appears to be an approach preferable to the standard THA technique.
- MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- miniinvazivní chirurgické výkony MeSH
- náhrada kyčelního kloubu metody škodlivé účinky MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
