Tibiofemoral Varus Research Articles

Evaluation of the Kinesio Taping and Real-Time External Feedback Effects on Lower Extremity Function During Single-Leg Squat in Individuals With Tibiofemoral Varus Alignment

Background and Aims People with postural malalignment such as tibiofemoral varus (TFRV) may experience movement patterns dysfunction during functional activities that are related to non-contact lower extremity injuries. Training protocols should be designed for these people to control and improve their functional dysfunctions. The present study aimed to investigate the effect of posterior X-taping (PXT) and real-time external feedback (RTF) on kinematic and electromyographic indices of the lower extremities during the single-leg squat task in individuals with TFRV. Methods Electromyographic and kinematic information of the lower extremities of 24 recreational athletes with TFRV (PXT=12, RTF=12) were recorded while participants in both groups performed single-leg squat 5 times consecutively and took a 2-minute rest between two different conditions (before and after the intervention). To analyze the data, 2-way analysis of variance and Bonferroni post hoc test were used at the significant level of P≤0.05. Results The present study results indicated an increase in gluteus medius muscle activity (P=0.013) in the eccentric phase and a decrease in hip adduction (P=0.001) in maximal knee flexion (P=0.034) after the intervention compared to before the intervention in the RTF group. Also, there was a reduction in external tibiofemoral rotation of the knee after the intervention compared to before intervention in maximal knee flexion (P=0.034), eccentric phase (P=0.001), and concentric phase (P=0.001) in the PXT group. In addition, there was a decreased ankle pronation after the intervention compared to before the intervention in the eccentric phase (P=0.001) and concentric (P=0.001) in the PXT group and in the eccentric phase (P=0.004) in the RTF group. Besides, there was an increased ankle abduction after the intervention compared to before the intervention in the concentric phase (P=0.001), eccentric phase (P=0.001), and maximum knee flexion (P=0.004) in the PXT group, and in the eccentric phase in the RTF group (P=0.006). Finally, there was a decrease in ankle flexion dorsiflexion at maximum knee flexion after the intervention compared to before the intervention (P=0.017) in the RTF group. Conclusion The results of the present study showed that PXT and RTF interventions can affect the kinematic parameters of individuals with TFRV malalignment in different ways and can be used to correct immediately postural defects during the single-leg squat task.

The effects on joint functions of biplanar distal tubercle open-wedge high tibial osteotomy: A prospective study.

Distal tubercle biplanar open-wedge high tibial osteotomy (DT-BOWHTO) is a method frequently applied in the treatment of knee joint medial osteoarthritis. The aim of this study was to evaluate the radiological, clinical, and functional results of patients at 5 years after DT-BOWHTO surgery. The study included a total of 41 patients who underwent DT-BOWHTO, comprising 19 (46.3%) males and 22 (53.7%) females with a mean age of 55.54 ± 4.17 (45-63) years and mean follow-up of 66.76 ± 6.29 (60-81) months. Statistical comparisons were made of the preoperative and postoperative body mass index (BMI), modified Insall-Salvati index, Blackburn-Peel index, Kelgren-Lawrence classification (KLC), tibial slope angle, American Knee Society Functional Score (AKSFS), Clinical American Knee Society Score (CAKSS), visual analog scale (VAS) pain score, Tegner Functional Activity Score (TFAS), total corrected angular measurements (TCA), and the tibio-femoral varus angle. Compared to the preoperative values, no statistically significant difference was determined in the postoperative modified Insall-Salvati index, Blackburn-Peel index, and tibial slope angle values (P > .05), and a statistically significant difference was determined in the BMI, AKSFS, CAKSS, VAS, KLC, tibio-femoral varus angle, and TFAS values (P ≤ .001). When the preoperative and postoperative BMI values were compared in 3 groups of normal, overweight, and obese, there was found to be a statistically significant difference (P = .014). No significant correlation was determined between the BMI values and the VAS and KLC values (P > .05). No significant correlation was determined between the total corrected angular and the preoperative and postoperative pain, and clinical and functional knee scores (VAS, AKSFS, CAKSS, TFAS) (P > .05). DT-BOWHTO was seen to provide extremely good 5-year results in the knee clinical findings, pain severity, and functional results. As the patella height and tibial slope angle were not changed, this did not cause the development of osteoarthritis in the patellofemoral and tibiofemoral joints. Grafting and fixation of the tibial tubercle with additional screws in the application of DT-BOWHTO were not seen to make any additional contribution to the healing of the osteotomy line. There was no relationship between increased BMI, reduced pain, and increase in knee functions in patients who underwent DT-BOWHTO.

The effects of the Posterior X Taping versus augmented feedback on lower-extremity kinematic and muscle activity pattern during unilateral weight-bearing activities in men with tibiofemoral varus malalignment

PurposeTibiofemoral Varus Malalignment (TFRV) contributes to overuse injuries by altering lower limb biomechanics. Both Posterior X Taping (PXT) and Real Time Feedback (RTF), have each been recommended for subjects with TFRV as they are thought to enhance control of excessive tibiofemoral rotations. This paper evaluates this claim.MethodsA total of recreational male 24 athletes with TFRV participated in the current study. Kinematic and electromyography variables of lower extremity were synchronously ​recorded on five consecutive repetitions of the single-legged-squat (SLS) and forward-step-down) FSD) tasks before and after applications of PXT and RTF.ResultsThe subjects at post-intervention in RTF group exhibited decreased hip adduction during FSD, and decreased hip adduction and internal rotation during eccentric and concentric phases of the SLS; Additionally, we observed increased gluteus medius activity during eccentric phase of the SLS and FSD tasks. In contrast, subjects at the post-intervention in PXT group exhibited decreased tibiofemoral external rotation and increased ankle external rotation during all the phases of both SLS and FSD tasks.ConclusionThese results suggest that the PXT and RTF interventions are recommended to immediately improve the functional defects of the subjects with TFRV during SLS and FSD tasks.

Effects of the real-time feedback and knee taping on lower-extremity function during ergometer pedaling in subjects with tibiofemoral varus alignment

BackgroundThe effect of the Posterior X Taping (PXT) used for subjects with Tibiofemoral Varus Malalignment (TFRV) aimed to control excessive tibiofemoral rotations is still unclear. Further, it is critical to use evidence-based therapeutic exercises to prevent non-contact injuries, especially in repetitive movements. ObjectiveTo investigate whether the PXT and real-time feedback (RTF) interventions would improve lower extremity functions during the pedaling task in subjects with TFRV. MethodsTwenty-four male recreational athletes with TFRV participated in this study; Kinematic and muscle activity were synchronously recorded on ten consecutive pedal cycles during the last 30 s of 2-min pedaling. ResultsThe present study indicated that the subjects at the post-intervention of the RTF group exhibited significant decreased hip adduction and internal rotation, significant decreased tibiofemoral external rotation between 144° and 216° of crank angle, significant increased vastus medialis activity between 144° and 288° of crank angle, and significant increased gluteus medius activity between 180° and 144° of crank angle; In contrast, the subjects at the post-intervention of the PXT group exhibited significant decreased tibiofemoral external rotation and increased ankle external rotation at all the crank angles. No between-group differences were observed in pre-and post-intervention. SignificanceThese results suggest that the PXT and RTF interventions are recommended to immediately improve the functional defects of the subjects with TFRV during the pedaling task.

UNLOADING REDUCES OSTEOARTHRITIS IN AN OVINE MODEL OF PARTIAL MEDIAL MENISCECTOMY

Purpose: Although osteoarthritis (OA), a leading cause of disability, has been associated with joint alignment, scientific translational evidence for this link is lacking. High tibial osteotomy (HTO) reduces unicompartmental overload, representing a causative therapy for symptomatic medial tibiofemoral varus knee OA. Here, we validate in a preclinical large animal model the effect of valgus HTO on the pattern of OA development induced by partial medial anterior meniscectomy (pMMx) in the osteochondral unit at two time points.

Isolated high tibial osteotomy is appropriate in less than two-thirds of varus knees if excessive overcorrection of the medial proximal tibial angle should be avoided

PurposeTo perform a detailed deformity analysis of patients with varus alignment and to define the ideal osteotomy level (tibial vs. femoral vs. double level) to avoid an oblique joint line.MethodsA total of 303 digital full-leg standing radiographs of patients aged 18–60 years and varus alignment [mechanical tibiofemoral varus angle (mFTA) ≥ 3°] were included. All legs were analyzed regarding mFTA, mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal femur angle (mLDFA), and joint line convergence angle. Based on mFTA, varus alignment was categorized as “mild” (3°–5°), “moderate” (6°–8°), or “severe” (≥ 9°). Deformity location was determined according to the malalignment test described by Paley. Two osteotomy simulations were performed with different upper limits for mMPTA: anatomic correction (mMPTA ≤ 90°, mLDFA ≥ 85°) and overcorrection (mMPTA ≤ 95°, mLDFA ≥ 85°). If a single osteotomy exceeded these limits at the intended mFTA of 2° valgus, a double-level osteotomy was simulated. If even a double-level osteotomy resulted in deviations from the defined limits, the leg was categorized as “uncorrectable”.ResultsMean mFTA was 6° ± 11° of varus (range 3°–15°). A tibial deformity was observed in 28%, a femoral deformity in 23%, a combined tibial and femoral deformity in 4%, and no bony deformity in 45%. The prevalence of a tibial deformity did not differ between varus severity groups, whereas a femoral and bifocal deformity was significantly more prevalent in knees with more distinct varus (p < 0.001). Osteotomy simulation revealed that isolated high tibial osteotomy (HTO) was appropriate in only 12% for anatomic correction, whereas a double-level osteotomy was necessary in 63%. If overcorrection of mMPTA was tolerated, the number of HTOs significantly increased to 57% (p < 0.001), whereas the number of double-level osteotomies significantly decreased to 33% (p < 0.001). Isolated DFO was considered ideal in 8% for both simulations. Significantly more knees were considered “uncorrectable” by simulating anatomic correction (18 vs. 2%; p < 0.001). A double-level osteotomy was significantly more often necessary in knees with “severe” varus (p < 0.001).ConclusionLess than one-third of patients (28%) with mechanical varus ≥ 3° have a tibial deformity. If anatomic correction (mMPTA ≤ 90°) is intended, only 12% of patients can be corrected via isolated HTO, whereas 63% of patients require a double-level osteotomy. If slight overcorrection is accepted (mMPTA ≤ 95°), 57% of patients can be corrected via isolated HTO, whereas 33% of patients would still require a double-level osteotomy.Level of evidenceIII, cross-sectional study.

Reduction of in situ force through the meniscus with phased inner resection of medial meniscus: an experimental study in a porcine model

PurposePartial meniscectomy can cause osteoarthritic changes in knees, as inner portion as well as peripheral portion of meniscus is important. The hypothesis of this study was that the amount of the inner resection of medial meniscus affected the in situ forces through the meniscus and the tibial varus and external rotation under axial load.MethodsFourteen intact porcine knees were investigated with a six-degree of freedom robotic system and force/moment, and the three-dimensional path of intact knees were recorded by universal force sensor when an axial load of 300-N was applied at four different flexion angles (30°, 60°, 90°, and 120°). The same examination was performed on three phased inner resections (30%, 60%, and 90% width) of the medial meniscus. Finally, all paths were reproduced after total medial meniscectomy, and in situ forces of the medial meniscus were calculated based on the superposition principle. Changes in tibiofemoral varus/valgus and internal/external rotation alignment during an axial load were also calculated.ResultsIn situ forces of the medial meniscus decreased according to the amount of meniscal resection at all flexion angles. The reduction was significant in knees with inner resections of > 60% width at all flexion angles and even of 30% width at a flexion angle of 120° (p < .05). Incremental changes in the tibiofemoral varus alignment increased depending on the inner resection width at all flexion angles (p < .05).ConclusionThe amount of inner resection of the medial meniscus was related to reduction of its in situ forces and increment of the tibial varus rotation under axial load.

When to Use a Condylar Constrained Insert in Non-Stemmed Posterior-Stabilized Total Knee Arthroplasty.

BackgroudThe constrained insert with non-stemmed tibial and femoral components can be used in the modern total knee arthroplasty (TKA) when soft-tissue balance and adequate stability from a posterior-stabilized (PS) insert cannot be achieved. This study aimed to identify the prevalence and predictive factors associated with the constrained insert use during primary TKA for varus deformity.MethodsFrom August 2016 to March 2019, 554 primary TKAs were consecutively performed by one surgeon. The choice of using a conventional PS polyethylene insert versus a constrained insert was made by the surgeon, depending on the stability detected after an attempt to balance the soft tissue. The decision to convert to a constrained liner was made if the ligament could not be balanced, if flexion-extension gaps were mismatched, or if the varus-valgus opening was 3 mm or more when varus and valgus stress tests at 0° were applied. We retrospectively investigated the preoperative, intraoperative, and postoperative factors associated with the constrained insert use. Multiple logistic regression analysis was used to identify predictive factors of constrained insert use, and a receiver operating characteristic curve analysis was used to pinpoint a cutoff value of tibiofemoral varus angle.ResultsConstrained inserts were used in 130 of 497 varus knees (26.1%). A multivariate analysis revealed that the factors associated with an increased adjusted risk of constrained insert use included preoperative severe varus deformity (odds ratio [OR], 5.78; 95% confidence interval [CI], 2.75–12.16; p < 0.001) and severe release of soft tissue through the superficial medial collateral ligament (OR, 6.38; 95% CI, 2.94–13.85; p < 0.001). A preoperative anatomic tibiofemoral varus angle of > 19.8° was associated with the use of a constrained articulation with an area under the curve of 0.7 (95% CI, 0.4–0.8).ConclusionsPrevalence of 26.1% for constrained insert use was found in this study. Preoperative anatomic tibiofemoral varus angle of > 19.8° and severe release of soft tissue through the superficial medial collateral ligament were associated with the use of a constrained articulation. The findings from this study will help surgeons to improve efficiency of surgical sequence planning and provide counseling to patients regarding the associated cost.

Is Lower-limb Alignment Associated with Hindfoot Deformity in the Coronal Plane? A Weightbearing CT Analysis.

The goals of lower limb reconstruction are to restore alignment, to improve function, and to reduce pain. However, it remains unclear whether alignment of the lower limb and hindfoot are associated because an accurate assessment of hindfoot deformities has been limited by superposition on plain radiography. Consequently, surgeons often overlook hindfoot deformity when planning orthopaedic procedures of the lower limb. Therefore, we used weight-bearing CT to quantify hindfoot deformity related to lower limb alignment in the coronal plane. (1) Is lower-limb alignment different in varus than in valgus hindfoot deformities for patients with and without tibiotalar joint osteoarthritis? (2) Does a hindfoot deformity correlate with lower-limb alignment in patients with and without tibiotalar joint osteoarthritis? (3) Is joint line orientation different in varus than in valgus hindfoot deformities for patients with tibiotalar joint osteoarthritis? (4) Does a hindfoot deformity correlate with joint line orientation in patients with tibiotalar joint osteoarthritis? Between January 2015 and December 2017, one foot and ankle surgeon obtained weightbearing CT scans as second-line imaging for 184 patients with ankle and hindfoot disorders. In 69% (127 of 184 patients) of this cohort, a combined weightbearing CT and full-leg radiograph was performed when symptomatic hindfoot deformities were present. Of those, 85% (109 of 127 patients) with a median (range) age of 53 years (23 to 75) were confirmed eligible based on the inclusion and exclusion criteria of this retrospective comparative study. The Takakura classification was used to divide the cohort into patients with (n = 74) and without (n = 35) osteoarthritis of the tibiotalar joint. Lower-limb measurements, obtained from the full-leg radiographs, consisted of the mechanical tibiofemoral angle, mechanical tibia angle, and proximal tibial joint line angle. Weightbearing CT images were used to determine the hindfoot's alignment (mechanical hindfoot angle), the tibiotalar joint alignment (distal tibial joint line angle and talar tilt angle) and the subtalar joint alignment (subtalar vertical angle). These values were statistically assessed with an ANOVA and a pairwise comparison was subsequently performed with Tukey's adjustment. A linear regression analysis was performed using the Pearson correlation coefficient (r). A reliability analysis was performed using the intraclass correlation coefficient. Lower limb alignment differed among patients with hindfoot deformity and among patients with or without tibiotalar joint osteoarthritis. In patients with tibiotalar joint osteoarthritis, we found knee valgus in presence of hindfoot varus deformity and knee varus in presence of hindfoot valgus deformity (mechanical tibiofemoral angle 0.3 ± 2.6° versus -1.8 ± 2.1°; p < 0.001; mechanical tibia angle -1.4 ± 2.2° versus -4.3 ± 1.9°; p < 0.001). Patients without tibiotalar joint osteoarthritis demonstrated knee varus in the presence of hindfoot varus deformity compared with knee valgus in presence of hindfoot valgus deformity (mechanical tibiofemoral angle -2.2 ± 2.2° versus 0.9 ± 2.4°; p < 0.001; mechanical tibia angle -1.8 ± 2.1° versus -4.3 ± 1.9°; p < 0.001). Patients with more valgus deformity in the hindfoot tended to have more tibiofemoral varus (r = -0.38) and tibial varus (r = -0.53), when tibiotalar joint osteoarthritis was present (p < 0.001). Conversely, patients with more valgus deformity in the hindfoot tended to have more tibiofemoral valgus (r = 0.4) and tibial valgus (r = 0.46), when tibiotalar joint osteoarthritis was absent (p < 0.001). The proximal joint line of the tibia had greater varus orientation in patients with a hindfoot valgus deformity compared with greater valgus orientation in patients with a hindfoot varus deformity (proximal tibial joint line angle 88.5 ± 2.0° versus 90.6 ± 2.2°; p < 0.05). Patients with more valgus deformity in the hindfoot tended to have more varus angulation of the proximal tibial joint line angle (r = 0.31; p < 0.05). In patients with osteoarthritis of the tibiotalar joint, varus angulation of the knee was associated with hindfoot valgus deformity and valgus angulation of the knee was associated with hindfoot varus deformity. Patients without tibiotalar joint osteoarthritis exhibited the same deviation at the level of the knee and hindfoot. These distinct radiographic findings were most pronounced in the alignment of the tibia relative to the hindfoot deformity. This suggests a detailed examination of hindfoot alignment before knee deformity correction at the level of the proximal tibia, to avoid postoperative increase of pre-existing hindfoot deformity. Other differences detected between the radiographic parameters were less pronounced and varied within the subgroups. Future research could identify prospectively which of these parameters contain clinical relevance by progressing osteoarthritis or deformity and how they can be altered by corrective treatment. Level III, prognostic study.

Effect of rotational prosthetic alignment variation on tibiofemoral contact pressure distribution and joint kinematics in total knee replacement.

In total knee replacement surgery, implant alignment is one of the most important criteria for successful long-term clinical outcome. During total knee replacement implantation, femoral and tibial alignment are determined through appropriate bone resections, which could vary based on patient anatomy, implant design and surgical technique and further influence loading conditions and clinical outcomes. The current research focused on three critical alignment parameters for total knee replacement insertion: femoral component internal/external (I/E) rotation, varus-valgus tibiofemoral angulation and posterior tibial slope. A computational finite element model of total knee replacement implant was developed and validated comparing with kinematic outputs generated from experimentally simulated knee joint motion. The FE model was then used to assess 12 different alignment scenarios based on previous case reports. Postoperative knee kinematics and joint contact pressure during simulated gait motion were assessed. According to the parametric study, FE model cases with femoral rotation revealed extra tibial I/E rotation in the predefined direction but negligible change in tibial anterior-posterior translation; cases with increased tibial slope showed notably increased tibial external rotation and anterior translation; cases with varus tibiofemoral angle presented slightly more tibial external rotation, whereas cases with valgus angle presented an observable increase in tibial internal rotation at the middle phase of the gait cycle. Finally, the response surface obtained from the postprocessing study demonstrated good statistical correlation with existing case study results, providing reliable estimation of peak tibiofemoral contact pressure affected by combinations of alignment parameters. The observations indicate that femoral external alignment should be favored clinically for enhanced patellar tracking and reduced contact pressure concentration for better long-term performance. Posterior tibial slope enables deep knee flexion. Extra femoral internal rotation as well as tibiofemoral varus-valgus alignment could be avoided in surgery due to deficiency in patellar tracking and high pressure concentration.

Comparative Study of Two Techniques for Ligament Balancing in Total Knee Arthroplasty for Severe Varus Knee: Medial Soft Tissue Release vs. Bony Resection of Proximal Medial Tibia

PurposeBony resection of the proximal medial tibia, an alternative technique for soft tissue balancing in total knee arthroplasty (TKA), was compared to the conventional medial soft tissue release technique.Materials and MethodsFrom June 2005 to June 2007, we performed 40 TKA in 27 patients with ≥10° tibio-femoral varus deformity. The conventional, medial soft tissue release technique was applied in 20 cases and bony resection of proximal medial tibia in the other 20 cases (vertical osteotomy group). Total operation time, knee range of motion (ROM), hospital for special surgery (HSS) scores, and tibio-femoral medial-lateral gap ratio in 0°, 90°, and 130° flexion at postoperative 6 months were compared between the groups.ResultsThe total operation time was shorter in the vertical osteotomy group. Tibio-femoral medial-lateral gap ratio in 130° flexion was closer to 1 in the vertical osteotomy group (p=0.000). There was no significant difference in the ROM, HSS score, or tibio-femoral medial-lateral gap ratio in 0° and 90° flexion at postoperative 6 months.ConclusionsIn severe varus knees, bony resection of proximal medial tibia can be considered as an alternative technique, in order to decrease total operation time and to obtain medial-lateral, soft-tissue balance in deep flexion.

Coronal malposition effects in total knee arthroplasty: a finite element analysis

Prosthetic component malposition is not infrequent, because of technical flaws, especially without a computed navigation system. We assumed that an inclined interline of a prosthetic knee with components parallel in the coronal plane provides a better load distribution and lower contact pressure towards a varus malalignment. For that we studied, using finite element analysis, load intensity and distribution for three situations: ideal alignment of prosthetic components, tibial varus malposition of 3° and 8° leading to tibio-femoral varus malalignment (i.e. an unbalanced knee) and the same tibial varus malpositions, but with the femoral component also malpositioned in the coronal plane, so that they are parallel, and with equally tightened collateral ligaments (i.e. a balanced knee). We found that maximum contact pressure and underlying bone compression forces are higher for a balanced knee with an inclined interline than in ideal alignment, but lower than in an unbalanced knee. According to our results, 2- and 4-mm additional medial plateau resection on a proper balanced knee does not significantly affect the load distribution towards ideal alignment. Balancing is a key factor for prosthetic survival in cases when a certain degree of coronal malposition cannot be avoided.

Correcting Varus Deformity

We report our technique and the results of treating severe intra- and extra-articular varus deformity using posterior stabilized fixed-bearing implants. We used a technique of selective posteromedial release and reduction osteotomy of posteromedial tibial flare in 173 knees in 117 patients. Proximal tibial osteotomy was used to correct severe extra-articular deformity. Mean tibiofemoral varus of 22° preoperatively was corrected to 5.3° valgus postoperatively. A total of 86% knees were in 4° to 10° valgus postoperatively. Mean Knee Society score improved from 22.8 to 91.1, and function score from 22.8 to 72.1 at 2 to 9 years. Of 30 bone grafts for tibial defects, 28 were successfully incorporated. No patient reported significant instability. Three knees showed tibial component loosening. Our technique restored alignment and stability without the need for constrained implants.

Q-angle influences tibiofemoral and patellofemoral kinematics

Numerous surgical procedures have been developed to correct patellar tracking and improve patellofemoral symptoms by altering the Q-angle (the angle between the quadriceps load vector and the patellar tendon load vector). The influence of the Q-angle on knee kinematics has yet to be specifically quantified, however. In vitro knee simulation was performed to relate the Q-angle to tibiofemoral and patellofemoral kinematics. Six cadaver knees were tested by applying simulated hamstrings, quadriceps and hip loads to induce knee flexion. The knees were tested with a normal alignment, after increasing the Q-angle and after decreasing the Q-angle. Increasing the Q-angle significantly shifted the patella laterally from 20° to 60° of knee flexion, tilted the patella medially from 20° to 80° of flexion, and rotated the patella medially from 20° to 50° of flexion. Decreasing the Q-angle significantly tilted the patella laterally at 20° and from 50° to 80° of flexion, rotated the tibia externally from 30° to 60° of flexion, and increased the tibiofemoral varus orientation from 40° to 90° of flexion. The results show that an increase in the Q-angle could lead to lateral patellar dislocation or increased lateral patellofemoral contact pressures. A Q-angle decrease may not shift the patella medially, but could increase the medial tibiofemoral contact pressure by increasing the varus orientation.

Survival analysis and predictors of failure in unicompartmental knee replacement using a PCA prosthesis

We evaluated 109 unicompartmental Porous Coated Anatomic arthroplasties after a mean follow up of 2.7 (range 0.25–5.9) years. In 91 medial arthroplasties the mean preoperative tibiofemoral varus angle of 1.3° (±4.2°) was corrected to 6° valgus ( P < 0.001). Correspondingly, in 18 lateral arthroplasties, 16.2° (±4.8°) valgus was realigned to 7.7° valgus ( P < 0.001) after operation. There were indications for revision in 27 cases. Conversion to total arthroplasty has been performed in 16 knees, and in four knees tibial and/or femoral components have been exchanged. The main reason for revision was polyethylene wear which had resulted in increasing varus or valgus deformity. According to statistical analysis, clinical findings at follow up (first step pain and contracompartmental pain) and lateral knee replacement predicted the risk of revision. Estimated cumulative survival at 3.7 years was 77% for the medial, and 45% for the lateral replacements, respectively ( P = 0.3159).