Under-corrected knees do not fail more than aligned knees at 8 years in fixed severe valgus total knee replacement

Is limb overcorrection following total knee arthroplasty compromising functional outcome?

Purpose

Many patients remain unsatisfied after total knee arthroplasty (TKA). Personalized alignment strategies have gained popularity in the search to improve patient satisfaction and function. This study aimed to examine the impact of limb overcorrection in the coronal plane on patient satisfaction and functional outcome. The secondary aim was to investigate how a change in knee phenotype following TKA affects clinical outcome.

Methods

A retrospective matched case-control study was designed between patients with limb overcorrection (N = 37) and a control group (N = 104). Mean follow-up was 68 months. Satisfaction and function were compared by means of the new 2011 Knee Society Score (KSS) and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Radiological evaluation was performed on weight-bearing full-leg radiographs. Overcorrection was defined as a mechanical HKA (mHKA) angle of 2° or more and opposite to the preoperative alignment. The control group consisted of TKAs that were corrected to neutral or left in slight undercorrection. Finally, component alignment (lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA)) and Coronal Plane Alignment of the knee (CPAK) phenotypes were evaluated.

Results

The overcorrection group performed better than the control group in terms of KSS subscores satisfaction and functional activities, total KSS score, all KOOS subcategories, and total KOOS score. Subdivision of the control group into a neutral and undercorrection group, and the overcorrection group into mild and severe overcorrection, revealed similar findings.A chance in knee phenotype as per aHKA, JLO or CPAK did not result in worse clinical outcomes.

Conclusion

Accidental limb overcorrection after TKA does not result in inferior clinical outcomes or patient satisfaction at midterm follow-up.The present study could not identify an optimal coronal alignment target. This suggests that coronal alignment as a predictor of patient satisfaction and function is likely less important than previously believed.

Level of evidence

Level III, retrospective case-control study.

Robotic total knee arthroplasty for moderate to high-grade valgus knee deformity: technique and outcomes

INTRODUCTION

Although the surgical techniques and functional outcomes of conventional total knee arthroplasty (TKA) are well-established, there is limited data available on robotic arm-assisted TKA (RATKA) in the context of valgus knee arthroplasty. The purpose of this study is to assess the efficacy of RATKA in the correction of moderate to severe valgus knee deformities using minimally constrained implants and to evaluate the short-term functional outcomes associated with this technique.

METHODS

This prospective study was conducted on patients with moderate to severe grade valgus knee deformity who underwent RATKA from August 1, 2020 to May 31, 2022. Of 873 primary RATKA cases, 48 cases had valgus knee deformities. Among these, 27 had grade 2-3 valgus with intact medial collateral ligament (MCL), two had grade 3 valgus with incompetent MCL, 14 had grade 1 valgus, and five had post-traumatic valgus deformities. Over a two-year follow-up period, functional outcomes were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Society Score (KSS), and complications were documented; however, radiological outcomes were not analyzed.

RESULTS

Among 27 patients with Grade 2-3 valgus, the final cohort included 21 patients (24 knees). The mean age was 58.33 ± 9.63 years and 70.8% were female. Ten (41.7%) patients had rheumatoid arthritis and 14 (58.3%) had degenerative osteoarthritis (OA). The median surgical time was 68.00 (13.00) minutes, and the median blood loss was 478.45 (176.25) mL. The valgus grade was reduced from a baseline value of 22.43 ± 7.05 degrees to 5.26 ± 1.53 degrees at 6 weeks. The WOMAC scores improved from 67.58 ± 7.27 at baseline to 1.38 ± 0.57 in the second year post-operatively. Similarly, the KSS scores improved from 26.67 ± 10.34 at baseline to 181.96 ± 7.20 in the second year. One patient sustained a Type II supracondylar femur fracture after a fall, managed with distal femur arthroplasty, while another had delayed tibia pin tract healing, treated with antibiotics and dressings.

CONCLUSION

RATKA facilitates precise correction of moderate to severe valgus deformity through enhanced surgical planning and execution, achieving adequate functional outcomes with minimal complications through the application of functional alignment philosophy.

Can robotic arm-assisted total knee arthroplasty be applied to valgus deformity

INTRODUCTION

Total knee arthroplasty (TKA) in valgus knees is challenging. Optimal ligament balance, implant neutral or moderate valgus alignment are crucial but conventional instrumentations usually lead to outliers. Robotic arm assisted TKA (RATKA) advantages could answer this challenge. Objectives were to assess RATKA frontal alignment accuracy for valgus knees, rotational femoral component reliability, revision surgery rate and functional outcomes for this population.

METHODS

This study is based on a continuous series of 454 RATKA. Implants were positioned according to a patient-specific alignment and postero-stabilised inserts were used. Valgus values, range of motion, KOOS and revision surgery rates were assessed at one-year postoperative. Femoral component rotation was analysed intraoperatively.

RESULTS

MAKO navigation system confirmed valgus preoperative deformity for 34 patients. Mean postoperative valgus value was - 1.5°±1.53 (range, -5 to 1), 85% patients had a residual valgus between 0 and - 3°, 97% of patients had a difference < 3° between valgus planned and valgus measured at one year postoperatively. Mean femoral rotation was + 2.65°±1.87 (range, 0 to 6.8°) of external rotation related to posterior condylar angle. No revision surgery has been performed. Mean KOOS value at one year was 80.79. 76% of patients (n = 26) had a good (70-80) or excellent (> 80) KOOS score. Mean flexion value was 133°±12 (range, 100 to 140).

CONCLUSION

RATKA can be applicable in valgus knee, offering high precision in component positioning with very few outliers. It also facilitates component rotation positioning, providing excellent functional results and ROM.

Achieving Better Clinical Outcomes After Total Knee Arthroplasty in Knees with Valgus Deformity: The Role of Alignment Strategies

BACKGROUND

Personalized alignment in total knee arthroplasty (TKA) has demonstrated good functional outcomes for knees with varus alignment. However, limited research has explicitly addressed optimal alignment strategies for valgus knees. The aims of the current study were to assess the impact of the postoperative knee alignment and of the degree of correction of knee alignment on functional outcomes and satisfaction in a population with preoperative valgus and to evaluate the complication and revision rates based on postoperative alignment.

METHODS

This retrospective study included primary posterior-stabilized TKA with a preoperative hip-knee-ankle (HKA) angle of ≥180°, with a minimum follow-up of 32 months. There were 460 knees included, divided into 3 groups: (1) preoperative neutral alignment (180° to 183°) (n = 162), (2) preoperative mild valgus (184° to 190°) (n = 204), and (3) preoperative severe valgus (>190°) (n = 94). A standardized surgical technique was employed with a goal of achieving neutral postoperative alignment. Data on radiographs, Knee Society Scores (KSS), range of motion, satisfaction, complications, and revisions were collected at the last follow-up.

RESULTS

The mean follow-up was 74.3 ± 12.4 months. In the preoperative mild valgus group, 10.8% of patients had postoperative varus, 81.4% had postoperative neutral alignment, and 7.8% had postoperative valgus. In the preoperative severe valgus group, 4.3% had postoperative varus, 83.0% had postoperative neutral alignment, and 12.8% had postoperative valgus. In the preoperative mild valgus group, patients with postoperative neutral alignment had significantly higher satisfaction (p = 0.0004) and KSS function score (p = 0.031) than patients with postoperative valgus alignment. In the preoperative severe valgus group, patients with postoperative valgus alignment had significantly higher satisfaction (p = 0.035) and greater improvement of the KSS knee score (p = 0.014) than patients with postoperative neutral alignment. Functional outcomes were not impacted by the degree of HKA angle correction. There were significantly fewer complications (p = 0.022) and revisions (p = 0.007) in the preoperative mild valgus group when patients had a postoperative neutral alignment compared with a postoperative valgus alignment.

CONCLUSIONS

For preoperative mild valgus, correction to neutral alignment achieved better outcomes and fewer complications than leaving residual valgus. For preoperative severe valgus, retaining residual valgus postoperatively ensured satisfactory functional outcomes without increased complications.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Optimal Sequence of Corrective Surgeries for Concomitant Valgus Knee and Rigid Pes Planus Deformities: The Knee-First Approach

In patients requiring surgical correction of ipsilateral valgus knee and rigid pes planovalgus deformities, the optimal operative sequence is controversial. Growing evidence suggests these 2 deformities are related in etiology and interrelated in disease course. We present the case of a 72-year-old female with concomitant valgus knee and rigid pes planovalgus deformities successfully treated with total knee arthroplasty followed by triple arthrodesis and Achilles lengthening. Surgical correction of these deformities must be carefully planned between the operating surgeons to avoid over- or under-correction of alignment that could further impact gait. In contrast with the limited available literature, the authors recommend correction at the knee first and the foot and ankle second. Further prospective studies are needed to elucidate the best operative sequence in these patients.

Extra-articular biceps tendon supplement release in total knee arthroplasty for valgus deformity combined with severe flexion contracture

To investigate the efficacy of extra-articular biceps tendon supplement (EBS) release in the treatment of valgus knee with severe flexion contracture. We retrospectively studied 27 patients who received EBS release for valgus knee combined with severe flexion contracture from 2018 to 2021. The full-length radiograph of the lower limbs in a standing position was taken before and after the operation, and the tibiofemoral angles before and after the operation were measured on the full-length radiograph of the lower limbs. Knee joint motion measurement and KSS scoring were performed before and after the operation (3 months, 6 months, and 1 year), and the obtained data were compared before and after the operation to evaluate clinical results. Compared with preoperation, postoperative HKA (p < 0.01), ROM at 3 months (p < 0.01), 6 months (p < 0.01), and 1 year (p < 0.01) were significantly improved, and KSS scores at 3 months (p < 0.01), 6 months (p < 0.01), and 1 year (p < 0.01) were significantly improved. Our EBS release has good clinical results for the treatment of valgus knee with severe flexion contracture.

A case series of total knee arthroplasty with a non-constrained implant in 2nd and 3rd degree valgus deformity in knee osteoarthritis and medial collateral ligament insufficiency

INTRODUCTION

Osteoarthritis is one of the leading causes of disability and the most common degenerative disease of the knee that causes enormous pain. As many as 10-15 % of patients requiring total knee arthroplasty (TKA) present with valgus knee deformity. When fully constrained TKA is not possible, the surgeon must use a different method to achieve a good result.

CASE DESCRIPTION

A 56-year-old female with 3rd degree (48-degree) and a 62-year-old male with 2nd degree valgus knee (13-degree) with painful osteoarthritis were examined. Both have valgus thrust gait and medial collateral ligament (MCL) laxity and underwent TKA using non-constrained implants. During surgical exposure, MCL insufficiency was found in both patients, and MCL augmentation was performed. Post-operative assessment and 4-month follow-up were done through clinical and radiological parameters using the knee scoring system.

DISCUSSION

A good outcome could still be achieved with a primary TKA implant in severe and moderate valgus knees with MCL insufficiency using MCL augmentation. The primary TKA implant proved to improve clinical and radiological parameters after 4 months of follow-up. Clinically, both patients no longer felt pain in their knees and were able to walk with better stability. Radiologically, there was a much-reduced valgus degree. The results were the first case went from 48-degree to 2-degree and the second case went from 13-degree to 6-degree.

CONCLUSION

Knee osteoarthritis with valgus deformity and MCL insufficiency present surgical challenges during TKA. It is still possible to use in severe or moderate valgus with MCL insufficiency, which was proven by satisfactory clinical and radiological findings. Although a non-constrained option is not ideal, it is still the first choice in certain cases.

Effect of total knee arthroplasty for valgus knee correction on clinical outcome and patellar position

PURPOSE

The purpose was to investigate the effect of different degrees of valgus deformity correction on patellar position and clinical outcome in patients with valgus knees after total knee arthroplasty (TKA).

METHODS

We retrospectively analyzed and followed 118 patients with valgus knees. Based on the post-operative hip-knee-ankle (HKA), patients were divided into three groups: neutral (±3°), mild (3-6°), and severe (> 6°). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), range of motion (ROM), and Knee Society Score (KSS) were used to evaluate post-operative clinical efficacy. Also, the patellar tilt angle (ε-angle), congruence angle (θ-angle), and Insall-Salvati index (ISI) were used to represent the patellar position. Post-operative observation indicators included HKA, angle of the femur (α-angle), tibial angle (β-angle), femoral component flexion angle (γ-angle), and tibial component posterior slope angle (δ-angle).

RESULTS

All patients showed significant improvements in HKA, ROM, WOMAC, and KSS after operation (P < 0.001). Regarding patellar position, the ISI values decreased to varying degrees (P < 0.05). The patellar tilt angle was significantly increased in the severe valgus group compared to that in the mild valgus and neutral groups (P < 0.001). Univariate analysis showed that the degree of post-operative residual valgus was significantly affected by WOMAC, KSS, α-, ε-, and θ-angles.

CONCLUSION

Minor valgus undercorrection did not affect the short-term outcome after TKA; however, when the residual valgus angle was > 6°, the post-operative scores were significantly reduced. Inadequate valgus correction does not result in significant changes in patellar height but may increase the risk of poor patellar tracking.

Tibiofemoral lift-off and resulting laxity following total knee arthroplasty: Frequency in a series of 906 continuous cases and functional consequences at 4 years' follow-up in a case-control study

BACKGROUND

Tibiofemoral instability is one reason for early revision of total knee arthroplasty. It can be the consequence of tibiofemoral laxity, especially in the coronal plane with tibiofemoral lift-off. But does femoral condyle lift-off on conventional postoperative radiographs suggest the presence of laxity or potential instability? To our knowledge, this question has not yet been answered. This led us to conduct a retrospective study to evaluate (1) the frequency of lift-off on postoperative radiographs, (2) the relationship between lift-off and laxity in the short term and (3) the functional consequences of lift-off.

HYPOTHESIS

Postoperative lift-off is a rare event that is predictive of laxity.

METHODS

We carried out a single-center retrospective study using postoperative radiographs from patients who underwent primary total knee arthroplasty between 2014 and 2016. The sample consisted of 906 patients. Lift-off was defined as a tibiofemoral angle of 3° or more on immediate postoperative radiographs (day 0) that were non-weightbearing and had no stress applied. The functional outcomes were determined in the 17 patients identified as having lift-off who had been operated in the first year (2014) to ensure the follow-up was long enough. These patients were compared to 34 matched control patients who were operated the same year and chosen randomly among patients not having lift-off. The matching ratio was 2 controls to 1 case. Preoperative and surgical data were compiled from each patient's electronic medical record. Patients were evaluated at 4 years postoperatively using the subjective Oxford-48, objective HSS score, IKS score, overall patient satisfaction and stress radiographs of the knee. The cases of lift-off observed in 2014 (n=17) were paired with a control group of patients selected randomly during 2014.

RESULTS

The frequency of the lift-off event was 63/906 or 7%. The frequency was consistent over the three years studied: 7.1% in 2014 (19/269), 6.2% in 2015 (22/354) and 7.8% in 2016 (22/283). There was no significant difference between the two groups (17 with lift-off and 34 without) in the sex, age, body mass index and coronal plane deformity (preoperative HKA angle). At a mean follow-up of 4 years (range 12-49 months), the knees with postoperative lift-off had more laxity (p=0.002), particularly laxity when varus stress was applied (p=0.009). There were no other significant differences in the outcomes.

DISCUSSION

Immediate postoperative lift-off after total knee arthroplasty is not a rare event, with a 7% frequency in our study. While it reveals that laxity is present in the particular compartment, there is no evidence of functional consequences at 4 years' follow-up; however, a long-term assessment is required to verify this finding.

LEVEL OF EVIDENCE

III - case-control study.

Surgical epicondylar axis is not orthogonal to the femoral mechanical knee axis in valgus knees with primary osteoarthritis: Three-dimensional analysis according to knee coronal alignment in 112 patients

BACKGROUND

During total knee arthroplasty (TKA), most surgeons align the femoral component along the surgical epicondylar axis (SEA) considering it as orthogonal to the femoral mechanical axis. However, it is still unclear how SEA coronal alignment varies according to the native coronal knee alignment. The main goal of this study was to analyze the SEA orientation according to the native coronal knee morphotype.

METHODS

A total of 112 patients underwent a three-dimensional (3D) -planning-based TKA. The SEA was then determined by locating the epicondyles on 3D models. The 3D femoral and tibial mechanical axes were marked and the femoral (FMA) and tibial (TMA) mechanical angles were measured. The native HKA angle was measured as FMA + TMA. The SEA orientation angles were measured in the coronal (SEA-α) and axial (SEA-β) plane. SEA orientation was compared between the valgus, neutral, and varus knees.

RESULTS

The mean SEA-α angle was 90.2 ± 3° and the mean axial SEA-β angle was 92.2 ± 1.3°. The SEA-α angle was significantly higher in the valgus group compared with the neutral group (92.3 ± 2.9°, 90 ± 2.9°, P = 0.0009) whereas there was no significant difference in the SEA-α angle between the varus and the neutral group (89.7 ± 2.3°, 90 ± 2.9°, P = 0.32).

CONCLUSIONS

In contrast to the neutral and varus knees, the SEA was not orthogonal to the femoral mechanical axis in patients undergoing TKA for primary osteoarthritis. Our results suggest adapting the coronal alignment of the femoral component during TKA, while maintaining an average 2° valgus in valgus knees. By contrast, with varus and neutral knees, our data support the use of a mechanical alignment.

The Role of Stability and Alignment in Improving Patient Outcomes After Total Knee Arthroplasty

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Total knee arthroplasty (TKA) is an effective treatment option for many patients, but a small group of patients are dissatisfied following TKA.

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Alignment, in combination with balance, stability, and knee kinematics, is an important modifiable surgical factor that can affect patient outcomes.

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Driven by the subset of dissatisfied patients after TKA, new techniques have evolved in the search for a more anatomic reconstruction of individual knee morphology and a more accurate approximation of the individual lower-extremity alignment.

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There is a need to optimize 3 aspects of TKA to improve patient outcomes-mechanical tooling processes, implants that resurface the epiphysis, and techniques that respect the variable anatomy of patients.

Slight femoral under-correction versus neutral alignment in total knee arthroplasty with preoperative varus knees: a comparative study

Background

This study aimed to compare the short-term clinical results of slight femoral under-correction with neutral alignment in patients with preoperative varus knees who underwent total knee arthroplasty.

Methods

The medical records and imaging data were retrospectively collected from patients who had undergone total knee arthroplasty in our hospital from January 2016 to June 2019. All patients had varus knees preoperatively. Upon 1:1 propensity score matching, 256 patients (256 knees) were chosen and divided into a neutral alignment group (n=128) and an under-correction group (n=128). The patients in the neutral group were treated with the neutral alignment. In the under-correction group, the femoral mechanical axis had a 2° under-correction. The operative time, tourniquet time and the length of hospital stay in the two groups were recorded. The postoperative hip-knee-ankle angle, frontal femoral component angle and frontal tibial component angle were measured. Patient-reported outcome measures were also compared.

Results

The operative time, tourniquet time and the length of hospital stay in the under-correction group were significantly shorter than the neutral alignment group (P<0.05). At the 2-year follow-up, the under-correction group had a larger varus alignment (P<0.05) and a larger frontal femoral component angle (P<0.05), and the frontal tibial component angles of the two groups were comparable. Compared with the neutral alignment group, the slight femoral under-correction group had significantly better patient-reported outcome measures scores (P<0.05).

Conclusion

For varus knees treated with total knee arthroplasty, alignment with a slight femoral under-correction has advantages over the neutral alignment in terms of the shorter operative time and better short-term clinical results.

Level of evidence

III

Total knee arthroplasty in valgus knee deformity: is it still a challenge in 2021?

Total knee arthroplasty in valgus knee deformities continues to be a challenge for a surgeon. Approximately 10% of patients who undergo total knee arthroplasty have a valgus deformity. While performing total knee arthroplasty in a severe valgus knee, one should aware with the technical aspects of surgical exposure, bone cuts of the distal femur and proximal tibia, medial and lateral ligament balancing, flexion and extension gap balancing, creating an appropriate tibiofemoral joint line, balancing the patellofemoral joint, preserving peroneal nerve function, and selection of the implant regarding constraint. Restoration of neutral mechanical axis and correct ligament balance are important factors for stability and longevity of the prosthesis and for good functional outcome. Thus, our review aims to provide step by step comprehensive knowledge about different surgical techniques for the correction of severe valgus deformity in total knee arthroplasty.

[Limits of kinematic alignment and recommendations for its safe application]

BACKGROUND

Despite the growing clinical evidence "pro" kinematic alignment (KA) in primary total knee arthroplasty, the idea of this individualized implant positioning has not (yet) become established throughout the community. Many surgeons have concerns about the safety of the method and the universality of its application. Interestingly, comparative studies with unlimited indications for KA showed only little or no advantage over standard mechanical alignment in contrast to studies with strict indications showing a significant benefit.

QUESTION AND METHODOLOGY

This results in a discussion about possible indication limits for KA. The aim of this article is to summarize the current evidence and theoretical considerations regarding ideal and possibly non-ideal patients. Furthermore, the paper describes the "lessons learned" of the past years as a recommendation for safe use of the method.

RESULTS AND DISCUSSION

Based on current evidence, primary varus osteoarthritis appears to be a good indication for KA. A limitation, however, is extra-articular deformities that lead to a pathologically joint line angle. Instabilities of the collateral ligaments are to be considered as a contraindication. In contrast to varus type osteoarthritis, valgus deformities appear to be more critical for KA. Even though there is yet only limited evidence, especially the accompanying extra-articular pathologies of the hip and ankle pose an increased risk of failure. In our opinion, a restricted KA with an individualized component position but neutral overall limb alignment makes sense here. To analyze the suitability of KA and estimate the post-operative component position, weight-bearing long-leg x‑rays are recommended. Additional stress radiography is helpful in certain cases, as is the three-dimensional analysis of the anatomy by CT or MRI scans.

Satisfactory medium-term outcomes with lateral condylar sliver osteotomy to correct valgus deformity in total knee replacements

PURPOSE

To describe a surgical technique in correcting valgus deformity during total knee replacement and evaluate medium-term clinical outcomes.

METHODS

This was a retrospective consecutive series of total knee replacement for severe valgus deformity of patients who underwent a lateral ligament complex release with a sliver osteotomy of the lateral femoral condyle with a minimum 1-year follow-up and recording objective and patient-reported outcome measures.

RESULTS

Twenty-three patients (25 knees) were included with median follow-up of 5 years (range 1-15 years) and average age 67.7 years (range 43-87). The primary diagnosis was osteoarthritis in 14 patients (61%) and inflammatory arthritis in 9 patients (39%). At final follow-up, the median mechanical tibiofemoral angle was restored to 4° (range 2-7) compared with a median valgus of 20° (range 13-30) preoperatively. This was statistically significant (P < 0.00001). Median Oxford Knee Score at final follow-up was 43 (range 36-48) indicating satisfactory outcomes. There were no revisions for any cause with a mean arc range of movement 110° (range 85-120).

CONCLUSION

This study shows that a technique utilising the familiar medial parapatellar approach, staged soft tissue releases, and a novel sliver lateral femoral condylar osteotomy with intact periosteum to release the lateral ligament complex leads to satisfactory medium-term outcomes, improved range of movement and patients' reported outcome measures. Sliver osteotomy is a useful technique in correcting valgus deformity in total knee replacements at medium-term follow-up.

LEVEL OF EVIDENCE

IV.

Computer assisted total knee arthroplasty for osteoarthritis to secondary to congenital dislocation of the patella: A case report

INTRODUCTION

Late presentation of congenital patella dislocation (CPD) with advanced osteoarthritis is very rare. Total knee arthroplasty (TKA) provides a valid treatment option for adults with CPD who have absence of the femoral sulcus and associated osteoarthritis. TKA for knee with CPD demand more precise technique because TKA correct the unusual pathologies for primary osteoarthritis, eg, tibial external rotation, absence of femoral groove, patella hypoplasia, and realignment of extensor mechanism.

CASE PRESENTATION

This case is a CPD with advanced osteoarthritis of left knee in a seventy-two-year old woman. We used a computer assisted navigation for a restoration of alignment, extension and flexion gap balancing, and mediolateral symmetry in the TKA, and operated it successfully.

CONCLUSION

TKA is a useful procedure for osteoarthritis of the knee in association with CPD. In hard case of osteoarthritis with CPD, computer assisted navigation is a useful tool for the TKA.