BACKGROUND: Total knee arthroplasty (TKA) with all-polyethylene tibial (APT) components has shown comparable survivorship and clinical outcomes to that with metal-backed tibial (MBT). Although MBT is more frequently implanted, APT equivalents are considered a low-cost variant for elderly patients. A biomechanical analysis was assumed to be suitable to compare the response of the periprosthetic tibia after implantation of TKA NexGen APT and MBT equivalent. METHODS: A standardised load model was used representing the highest load achieved during level walking. The geometry and material models were created using computed tomography data. In the analysis, a material model was created that represents a patient with osteopenia. RESULTS: The equivalent strain distribution in the models of cancellous bone with an APT component showed values above 1000 με in the area below the medial tibial section, with MBT component were primarily localised in the stem tip area. For APT variants, the microstrain values in more than 80% of the volume were in the range from 300 to 1500 με, MBT only in less than 64% of the volume. CONCLUSION: The effect of APT implantation on the periprosthetic tibia was shown as equal or even superior to that of MBT despite maximum strain values occurring in different locations. On the basis of the strain distribution, the state of the bone tissue was analysed to determine whether bone tissue remodelling or remodelling would occur. Following clinical validation, outcomes could eventually modify the implant selection criteria and lead to more frequent implantation of APT components.

• Klíčová slova
• All-polyethylene tibial component, Computational modeling, FEA, Finite element method, Knee replacement, Metal-backed tibial component, TKR, Total knee arthroplasty,
• MeSH
• analýza metodou konečných prvků MeSH
• kovy MeSH
• lidé MeSH
• polyethylen MeSH
• protézy - design MeSH
• protézy kolene * MeSH
• senioři MeSH
• tibie diagnostické zobrazování   chirurgie   MeSH
• totální endoprotéza kolene * MeSH
• Check Tag
• lidé MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kovy MeSH
• polyethylen MeSH

BACKGROUND AND OBJECTIVE: Total knee arthroplasty (TKA) with modern all-polyethylene tibial (APT) components has shown high long-term survival rates and comparable results to those with metal-backed tibial components. Nevertheless, APT components are primarily recommended for older and low-demand patients. There are no evidence-based biomechanical guidelines for orthopaedic surgeons to determine the appropriate lower age limit for implantation of APT components. A biomechanical analysis was assumed to be suitable to evaluate the clinical results in patients under 70 years. The scope of this study was to determine biomechanically the appropriate lower age limit for implantation of APT components. METHODS: To generate data of the highest possible quality, the geometry of the computational models was created based on computed tomography (CT) images of a representative patient. The cortical bone tissue model distinguishes the change in mechanical properties described in three parts from the tibial cut. The cancellous bone material model has a heterogeneous distribution of mechanical properties. The values used to determine the material properties of the tissues were obtained from measurements of a CT dataset comprising 45 patients. RESULTS: Computational modeling showed that in the majority of the periprosthetic volume, the von Mises strain equivalent ranges from 200 to 2700 με; these strain values induce bone modeling and remodeling. The highest measured deformation value was 2910 με. There was no significant difference in the induced mechanical response between bone models of the 60-year and 70-year age groups, and there was <3% difference from the 65-year age group. CONCLUSIONS: Considering in silico limitations, we suggest that APT components could be conveniently used on a bone with mechanical properties of the examined age categories. Under defined loading conditions, implantation of TKA with APT components is expected to induce modeling and remodeling of the periprosthetic tibia. Following clinical validation, the results of our study could modify the indication criteria of the procedure, and lead to more frequent implantation of all-polyethylene TKA in younger patients.

• Klíčová slova
• All-polyethylene tibial component, Bone mechanics, Finite element model, Orthopaedic biomechanics, Total knee arthroplasty, von Mises strain,
• MeSH
• analýza metodou konečných prvků MeSH
• biomechanika MeSH
• kovy MeSH
• lidé MeSH
• mechanický stres MeSH
• polyethylen MeSH
• protézy - design MeSH
• protézy kolene * MeSH
• tibie diagnostické zobrazování   chirurgie   MeSH
• totální endoprotéza kolene * metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kovy MeSH
• polyethylen MeSH

Numerous studies have compared metal-backed components (MBTs) and all-polyethylene tibial components (APTs), but none of them specifically analysed the clinical results and the overall patient preference in patients who had undergone a staged bilateral knee replacement. The purpose of this study is to compare clinical results, perceived range of motion, and overall implant preference among patients who had undergone staged bilateral knee replacement with an APT and contralateral knee replacement with MBTs. A dataset of 62 patients from a single centre who underwent staged bilateral TKA between 2009 and 2022 was selected and retrospectively analysed. Tibial component removal was performed in three knees overall, all of which had MBTs. The mean measured Knee Score (KS) of knees with APTs was 78.37 and that of contralateral knees with MBTs was 77.4. The mean measured Function (FS) of knees with APTs was 78.22, and that of contralateral knees with MBs was 76.29. The mean flexion angle of knees with APTs was 103.8 and that for knees with MBTs was 101.04 degrees. A total of 54.8% of the patients preferred the knee that received APTs over contralateral MBTs. In our cohort, TKA with an APT in one knee and an MBT in the contralateral knee recorded similar clinical results and perceived ranges of motion. Patients in general preferred the knee that received an APT over contralateral knee with an MBT.

• Klíčová slova
• all-polyethylene tibia, bilateral knee replacement, metal-backed tibia, staged bilateral knee arthroplasty, total knee arthroplasty,
• Publikační typ
• časopisecké články MeSH

PURPOSE OF THE STUDY Use of an all-polyethylene (all-poly, AP) tibial component in primary total knee arthroplasty is still an attractive option considering the durability of replacement, the elimination of backside wear and the lower cost compared to modular metalbacked tibia. The purpose of the study was to evaluate the long-term results of the total knee replacement using the P.F.C. Sigma system with a monoblock all-polyethylene tibial component implanted at the 1st Orthopedic Department of the St. Anne's University Hospital and Masaryk University Brno in the period 1999-2010. MATERIAL AND METHODS In the monitored period, 911 total knee replacements using P.F.C. Sigma with an all-polyethylene tibial component were performed. This cohort of patients was evaluated at least 10 years after the primary replacement surgery. Altogether 323 knee replacements in 289 patients were evaluated. The clinical outcomes were assessed according to the Knee Society Clinical Rating System (KSS) and the Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. The replacement survival was evaluated using the Kaplan-Meier survival analysis. RESULTS In the evaluated group, the average KS was 82.6 points and the average functional score was 74.7 points. Excellent results were recorded in 213 cases, good results in 78 and satisfactory in 23 replacements. Poor clinical results were reported in 9 patients. The average range of motion was 105.8°. In 5 knees (1.5%) revision surgery was performed for infection complications, 3 cases were complicated due to periprosthetic fractures, 4 replacements were revised due to anterior knee pain and 8 knees showed a limited range of motion. Only 1 replacement was revised for aseptic loosening, with no need for reimplantation of the component. The survivorship of the implant was 98.5 % at the follow-up of 12.8 years, including the reasons of reimplantation. DISCUSSION Total knee replacement with an all-polyethylene tibial component is not so popular as the metal-backed modular implants. The all-polyethylene tibial component has certain advantages: lower unit costs, no backside wear, no liner dislocation, possibility of conservative bone resection. On the other hand, this type of implant is not modular and augmentations or longer stems cannot be used. Even though this type of endoprosthesis is recommended exclusively for elderly patients with a lower level of activity, the current mid- and long-term results show that indications for all-poly implants are much broader. CONCLUSIONS The total knee replacement with an all-polyethylene tibial component shows very good long-term clinical outcomes with an excellent survival rate. The all-poly design is cost-effective and may be used not only in elderly patients. Key words: total knee replacement, all-polyethylene tibial component, long-term results.

• MeSH
• lidé MeSH
• následné studie MeSH
• polyethylen MeSH
• protézy - design MeSH
• protézy kolene * MeSH
• reoperace MeSH
• selhání protézy MeSH
• senioři MeSH
• tibie chirurgie   MeSH
• totální endoprotéza kolene * škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• polyethylen MeSH

PURPOSE: This study aims to compare total knee replacement (TKA) with NexGen All-Poly (APT) and NexGen Metal-Backed (MBT) in terms of implant survivorship, reasons leading to implant failure and functional results of defined age categories. METHODS: A single-centre, retrospective evaluation of 812 patients who underwent knee replacement with NexGen CR between 2005 and 2021, comparing a modern congruent APT component to a modular MBT equivalent component using a similar surgical technique at a notable mean follow-up duration. Implant survival, functional outcomes using the Knee Society Score and range of motion were evaluated and compared in different age categories. RESULTS: Of the 812 NexGen CR TKAs performed at our institution, 410 (50.4%) used APT components and 402 (49.6%) MBT components. The survival rate of NexGen APT was 97.1% and that of NexGen MBT was 93.2% (p = 0.36). Removal of the implant occurred overall in 15 cases, for MBT in ten cases, and for APT in four cases. The FS was proved to be significantly higher when APT components were implanted in younger patients than for MBT (p = 0.005). A similar range of motion between the components was recorded (p = 0.1926). CONCLUSION: Under defined conditions, we measured the clinical results of implants from a single manufacturer implanted in a single department using a similar surgical technique. Considering the limitations, we suggest that all-polyethylene tibial components are equal or even superior to metal-backed ones across the examined age categories.

• Klíčová slova
• All-polyethylene knee replacement, Implant survival, Knee Society Score, Knee arthroplasty, NexGen,
• MeSH
• kovy MeSH
• lidé MeSH
• polyethylen MeSH
• protézy - design MeSH
• protézy kolene * MeSH
• retrospektivní studie MeSH
• totální endoprotéza kolene * škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kovy MeSH
• polyethylen MeSH

PURPOSE OF THE STUDY: An analysis of long-term results of the all-polyethylene tibial component in Walter-Motorlet cemented condylar knee arthroplasty, with a standard tibial plateau (STP) of our own design. MATERIAL AND METHODS: A total of 49 patients underwent knee replacement; of them, 35 (71.4%) with 38 Walter-Motorlet implants using the STP were evaluated. The average age at the time of evaluation was 87.3 years. The follow-up ranged from 18 to 27 years (average, 24.6 years). Mechanical properties of the STP were tested by experimental measurements and in a photoelasticimetric study. The clinical results were evaluated according to the EULAR Knee Assessment Chart (EKACH). Twenty-four patients (26 knees; 49%) had osteoarthritis (OA) and 11 (12 knees; 23%) had rheumatoid arthritis (RA). Of the 14 (28.6%) patients not included in evaluation, seven (14.3%), with seven knees, required revision arthroplasty and seven (14.3%), with 10 knees, were lost to follow-up. RESULTS: Of the 38 implants evaluated by the EKACH at an average of 24.6 years, subjectively, 14 (36.8%) knees were free from pain and 14 (36.8%) were mildly painful. The remaining 10 (26.4%) joints were acutely painful on walking up or down the hill. In 14 (36.8%) cases the patients experienced their knees as stable. Light domestic chores were routinely performed by 17 patients (10 OA and 7 RA; 48.6%). One (2.9%) OA patient had a full-time job, and nine (25.7%) patients were socially independent. The functional outcome was significantly related to the patient's age at the time of evaluation. Complications included STP aseptic loosening in five (13.1%) and late infection in two (5.2%) knees. Radiography showed translucent zones below an all-polyethylene component in 14 (36.8%) knees. DISCUSSION The five cases of aseptic loosening may have been due to insufficient hardness of a U-shaped polyethylene component and long-term stress at the bone-implant interface. In the majority of knees the anterior cruciate ligament was defective or missing completely. Maintenance of the posterior cruciate ligament facilitates absorption of the greater part of forces at the cement-bone interface, as also reported by other authors. The high incidence of complications associated with patellar components, as described in the literature of the late 1970s and the early 1980s, led us to avoid the primary use of a patellar implant. CONCLUSIONS: Our evaluation showed that, in 73% of the cases, the all-polyethylene tibial component was a suitable and inexpensive implant with very good or good long-term results on average at 24.6 years of follow-up. Since the quality of currently produced polyethylene is high, we recommend the use of all-polyethylene tibial components in all indicated cases.

• MeSH
• artralgie prevence a kontrola   MeSH
• artróza kolenních kloubů patofyziologie   chirurgie   MeSH
• lidé MeSH
• následné studie MeSH
• obnova funkce MeSH
• polyethylen MeSH
• protézy - design * MeSH
• protézy kolene * MeSH
• revmatoidní artritida patofyziologie   chirurgie   MeSH
• selhání protézy MeSH
• senioři nad 80 let MeSH
• totální endoprotéza kolene přístrojové vybavení   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• senioři nad 80 let MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• polyethylen MeSH

PURPOSE OF THE STUDY: The kinematics of an intact knee joint and that of a knee replacement have been studied in many research centres. In the 1987 radiographic study, Bradley, Goodfellow and O'Connor reported the movement of a polyethylene insert in patients with unicompartmental Oxford knee replacement. Views with the knee at full extension and 90° of flexion were obtained and the movement of the meniscal bearings over this range of flexion was measured. The bearings were found to move backwards on the tibia through an average distance of 4.4 mm in all 16 patients. This measurement was in agreement with the then valid concept of knee biomechanics and a roll-back phenomenon. However, our observations had not always agreed with the results of these authors, but gave an impetus for a detailed evaluation of our own patient group. The aim of the study was to evaluate the dynamic relationship between the components of a unicompartmental Oxford knee replacement and elucidate it with the use of recent information from the field of biomechanics. A relationship of the obtained kinematic values to clinical outcomes was also investigated. Answers to the following hypotheses were sought: Would our results be in agreement with the British authors' findings? Would clinical outcomes depend on the kinematic properties of knee replacements? MATERIAL AND METHODS: The group comprised 33 patients, 23 women and 10 men. They all had replacement of the medial compartment of the knee. The construction of the unicompartmental Oxford Phase III knee replacement enabled us to locate the centre of rotation of the medial femoral condyle in relation to the tibial component at flexion and extension of the knee, using radiography. The patients were examined in a supine position with the knee at full extension, and subsequently views of the knee were obtained at 80°-90° flexion in accordance with the method used by the British authors. The clinical findings of knee joints were assessed using the American Knee Society (AKS) scoring system (Insall et al.). Pain was rated on the Visual Analogue Scale (VAS). The results were statistically evaluated with the t-test and Chi-square test. RESULTS: On moving the knee from extension to flexion, movement of the polyethylene insert ventrally by an average of 3.4 mm in relation to the tibia was recorded, i.e., "paradoxical" ventral translocation. In the patients with insert movement less than or equal to 3 mm, the average AKS score was 89 points, in those with movement over 3 mm it was 87 points. The average functional scores were 87 and 83 points in the patients with movement less than 3 mm and more than 3 mm, respectively. The average VAS score was 1.55 in the former and 1.18 in the latter. DISCUSSION: The unicompartmental Oxford Phase III knee replacement substitutes a flexion femoral facet and eliminates the role of an extension femoral facet. This is the reason why, at knee extension between -5° and +20°, the centre of rotation of the medial femoral condyle is in the centre of the flexion facet and not in that of the extension facet. When the stabilising functions of the extension tibial facet in the ventral direction and of the dorsal part of the insert in the dorsal direction are missing, the position of the contact surface centre becomes much dependent also on the strength and direction of external forces acting in the knee joint vicinity. CONCLUSIONS: The kinematic parameters of the unicompartmental Oxford Phase III knee replacement investigated in our group differed from the findings of the British authors. However, neither the magnitude nor the direction of movement had any effect on the clinical outcome of knee arthroplasty.

• MeSH
• biomechanika MeSH
• kolenní kloub patofyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• protézy kolene * MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• totální endoprotéza kolene * MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH

PURPOSE OF THE STUDY: The study evaluates mid-term results of total knee replacement with a zirconia ceramic (ZrO2) femoral component. MATERIAL: The evaluated group comprised 20 knees in 19 patients (4 men and 15 women). In one patient the replacement was performed bilaterally. Two patients had in the contralateral knee the same type of prosthesis with a femoral chrome-cobalt component.The mean age at the time of operation was 65.2 years (range, 38-81 years).The primary indication was 14 times osteoarthritis and 5 times rheumatoid arthritis. The average follow-up period was 6.5 years (range, 2.1-8.5 years). METHODS: Patients included in the study regardless of age, body mass and the basic diagnosis, agreed with the use of the ceramic femoral component. The evaluation covered a range of motion, mechanical axis, joint stability, pain, swelling, ability to walk on level ground and on stairs, subjective satisfaction (EULAR Knee Chart). Radiograph were assessed at one year intervals in two projections to identify the incidence of radiolucency around the implant. The Kaplan-Meier survival curve was used and compared with the survival curve in identical chrome-cobalt implants. RESULTS: At he final follow-up, 14 knees were evaluated, because 3 patients died without any connection with the implant, in one case the tibial component migrated due to necrosis of the tibial condyle in a patient with RA and two implants had to be revised and replaced due to polyethylene wear. No infection or negative tissue reaction was recorded in the evaluated group. The average flexion range was 109 degrees. All knees were stable and without swelling, in two cases there occurred slight femoropatellar pain. Twelve patients were fully satisfied, 2 patients were satisfied with a certain reservation. The differences in the course of the survival curves of chrome-cobalt and ceramic implants were statistically insignificant. DISCUSSION: Although the use of zirconia ceramics in vitro reduces the amount of polyethylene wear, the clinical outcomes of total knee replacements as compared to the hip are not convincing. One of the causes may be the substantially different and more complex biomechanics of the knee. Tribology improvement of the femoral ceramic component cannot compensate the deficiencies in the joint balancing in flexion and extension. The economically and technologically demanding production of these implants may be justified in patients with allergies caused by chrome-cobalt components. CONCLUSIONS: The results of mid-term follow-up of the use of zirconia ceramic femoral components proved no impact on the improvement of the period of survival of the knee implant. No adverse response to the material or mechanical failure of the ceramic components was encountered. Key words: total knee replacement, zirconia ceramic femoral component, TKR mid-term results, ceramic knee survival curve.

• MeSH
• artróza kolenních kloubů chirurgie   MeSH
• dospělí MeSH
• femur MeSH
• kolenní kloub diagnostické zobrazování   MeSH
• lidé středního věku MeSH
• lidé MeSH
• protézy kolene * MeSH
• rentgendiagnostika MeSH
• revmatoidní artritida chirurgie   MeSH
• selhání protézy MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• totální endoprotéza kolene * MeSH
• zirkonium * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• zirconium oxide MeSH Prohlížeč
• zirkonium * MeSH

PURPOSE OF THE STUDY: The aim of the study was to ascertain what proportion of patients undergoing total knee arthroplasty (TKA) complain of restricted knee joint motion, and to investigate options for improvement of this situation. MATERIAL: Our evaluation included a group of 796 patients treated with TKA at our department in the period from January 1, 1990, to December 31, 2004. In all cases, a condylar implant with preservation of the posterior cruciate ligaments was used. METHODS: In addition to medical history, the range of motion, knee joint malalignment and radiological findings were assessed before surgery. After THA, the type of implant and complications, if any, were recorded, and improvement in joint motion was followed up. Based on the results of Kim et al., flexion contracture equal to or higher than 15 degrees and/or flexion less than 75 degrees were made the criteria of stiffness after THA. Patients with restricted THA motion who had aseptic or septic implant loosening were not included. RESULTS: Of the 796 evaluated patients, 32 (4.14 %) showed restricted motion after total knee arthroplasty, as assessed by the established criteria. In 16 patients, stiffness defined by these criteria had existed before surgery, and three patients showed an excessive production of adhesions and heterotopic ossifications. In three patients, the implantation procedure resulted in an elevated level of the original joint line and subsequent development of patella infera and increased tension of the posterior cruciate ligament. Four patients declined physical therapy and, in six, the main cause of stiffness could not be found. Seventeen patients did not require surgical therapy for restricted motion; TKA provided significant pain relief and they considered the range of motion achieved to be sufficient. One patient underwent redress 3 months after surgery, but with no success. Repeated releases of adhesions, replacement of a polyethylene liner and revision surgery of the extensor knee structures were performed in 15 patients. In these, the average value of knee flexion increased by 17 degrees only and, in the patients suffering from excessive adhesion production, this value remained almost unchanged. Revision TKA was carried out in four patients, in whom knee joint flexion increased on average by 35 degrees to achieve an average flexion of 83 degrees. DISCUSSION: Restricted motion after TKA has been reported to range from 1.3 % to 12.0 %, but consistent criteria have not been set up. In our study it was 4.14 %. In agreement with the literature data, one of the reasons was pre-operative restricted motion, which was recorded in 16 of 32 patients. Similarly, also in our patients, biological predisposition to excessive production of fibrocartilage associated with adhesions in all knee joint compartments was the major therapeutic problem. Intra-operative fractures, ligament tears requiring post-operative fixation and unremoved dorsal osteophytes lead to the restriction of knee joint motion. By inadequate resection of articular surface, the original joint line may be at a higher level; this results in an increased tension of the posterior cruciate ligament and patella infera development, both influencing knee flexion. In our study, three patients were affected. Knee joint stiffness can also develop in patients declining physical therapy or in whom this is not correctly performed, often for insufficient analgesia. In contrast to the data reported in the literature, 17 of 32 patients in this study had no need for surgical treatment of restricted knee joint motion. Redress under general anesthesia was not effective. For markedly restricted motion of the knee joint, reimplantation can be recommended or, in less severe cases, an intervention on adjacent soft tissues. CONCLUSIONS: Restricted motion of the knee joint after TKA is difficult to treat and, therefore, prevention is recommended. This should include thorough conservative treatment of gonarthrosis, early indication for surgery, prevention of elevation in the joint line and consistent rehabilitation with appropriate analgesia. For severe stiffness of the knee joint, as evaluated by the criteria of Kim et al., revision arthroplasty can be recommended.

• MeSH
• kolenní kloub patofyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• protézy kolene MeSH
• rozsah kloubních pohybů * 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
• anglický abstrakt MeSH
• časopisecké články MeSH

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