Total knee arthroplasty in patients with substantial deformities using primary knee components

Background: Whether neutral alignment brings better clinical outcomes is controversial. Consideration of the preoperative knee condition of patients and some limitations of previous studies, we suggested that other index may be more important than a generic target of 0° ± 3° of a neutral axis to reflect changes in coronal alignment after total knee replacement (TKR). The purpose of this study was to explore the relationship between alignment and functional outcome with a new grouping method and the concept of correction rate. Methods: A new grouping method was adopted to divide patients into three groups based on the degree of correction of mechanical femoral-tibial angle (MFTA): neutral, under and over-correction. Hospital for Special Surgery (HSS) score were compared among the 3 groups. In addition, we also attempt to further explore whether the concept of correction rate can predict postoperative functional score. Results: HSS showed significant improvement in all groups. There was no difference in HSS or incremental scores based on the postoperative alignment category for the degree of correction of MFTA. The correlational analyses also didn’t find any relevant results.Conclusion: TKR is a soft tissue procedure and clinical outcome depends on many factors, only reaching neutral alignment after surgery may not mean a good clinical result. Therefore, categorization of optimal coronal alignment after TKR may be impractical. But we still believe that the concept of correction rate and new grouping method are worthy of research which can reflects the preoperative knee condition and the change of coronal alignment. Perhaps it can be better used in TKR in the future. Level of evidence: III.

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“…Because the anatomy of the varus knees often leads already to under-correction. This is consistent with some studies to some extent [35][36][37].…”

Section: Discussionsupporting

confidence: 94%

Degree of Coronal Alignment Correction Can’t Predict Knee Function in Total Knee Replacement

Zhu

Chen

Wang

et al. 2020

Preprint

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show abstract

“…Because the anatomy of the varus knees often leads already to undercorrection. This is consistent with some studies to some extent [35][36][37].…”

Section: Discussionsupporting

confidence: 94%

Degree of Coronal Alignment Correction Can’t Predict Knee Function in Total Knee Replacement

Zhu

Chen

Wang

et al. 2020

Preprint

View full text Add to dashboard Cite

Background: Whether neutral alignment brings better clinical outcomes is controversial. Consideration of the preoperative knee condition of patients and some limitations of previous studies, we suggested that other index may be more important than a generic target of 0° ± 3° of a neutral axis to reflect changes in coronal alignment after TKR. The purpose of this study was to explore the relationship between alignment and functional outcome with a new grouping method and the concept of correction rate. Methods: A new grouping method was adopted to divide patients into three groups based on the degree of correction of MFTA: neutral, under and over-correction. HSS were compared among the 3 groups. In addition, we also attempt to further explore whether the concept of correction rate can predict postoperative functional score. Results: HSS showed significant improvement in all groups. There was no difference in HSS or incremental scores based on the postoperative alignment category for the degree of correction of MFTA. The correlational analyses also didn’t find any relevant results. Conclusion: TKR is a soft tissue procedure and clinical outcome depends on many factors, only reaching neutral alignment after surgery may not mean a good clinical result. Therefore, categorization of optimal coronal alignment after TKR may be impractical. But we still believe that the concept of correction rate and new grouping method are worthy of research which can reflects the preoperative knee condition and the change of coronal alignment. Perhaps it can be better used in TKR in the future.

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“…Complicating this goal is that patients presenting with osteoarthritis often have either varus or valgus deformity. Significant deformities are more difficult to correct to neutral mechanical alignment if conventional instrumentation is used [ 37 , 38 ]. Depending on the degree of deformity, the surgical technique, and the choice of implant, the amount of necessary constraint might differ [ 38 , 39 ].…”

Section: Discussionmentioning

confidence: 99%

Second-generation bi-cruciate stabilized total knee system has a lower reoperation and revision rate than its predecessor

Christen¹,

Kopjar

2018

Arch Orthop Trauma Surg

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IntroductionTotal knee arthroplasty (TKA) can provide pain relief and good long-term results. However, nearly 30% of post-surgical patients are unsatisfied due to persistent pain and functional deficits. A second-generation bi-cruciate stabilized TKA device has a post-cam mechanism with an asymmetric femoral component, a polyethylene insert, and a medially concave and laterally convex shape. The device is designed to provide guided motion, and thus improve knee kinematics by more closely approximating a normal knee. The aim of this study was to evaluate early complication and revision rates of the second-generation device and to compare its clinical performance to the first-generation device.Materials and methodsIn this retrospective, longitudinal, non-concurrent cohort study, 140 TKAs were performed using the second-generation device on 131 patients from 2012 to 2016, and 155 TKAs were performed using the first-generation device on 138 patients from 2009 to 2012. Primary outcomes were occurrence of revisions and reoperations.ResultsThere were 31 reoperations [3.21 per 100 observed component years (OCY)] in 22 (2.28 per 100 OCY) TKAs in the first-generation device cohort compared to five reoperations (1.92 per 100 OCY) in four TKAs (1.54 per 100 OCY) in the second-generation device cohort. The adjusted hazard ratio (HR) was 3.50 (P = 0.0254). There were 21 revisions (2.17 per 100 OCY) in 16 (1.66 per 100 OCY) TKAs in the first-generation device cohort, compared to only three revisions (1.15 per 100 OCY) in two TKAs (0.77 per 100 OCY) in the second-generation device cohort. The adjusted HR was 4.16 (P = 0.0693).ConclusionThe improved design of the second-generation device appears to be associated with a lower risk of reoperation and revision compared to that of the first-generation device.Level of evidenceIII.

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Total knee arthroplasty in patients with substantial deformities using primary knee components

Abstract: III.

Cited by 40 publications

References 54 publications

Degree of Coronal Alignment Correction Can’t Predict Knee Function in Total Knee Replacement

Degree of Coronal Alignment Correction Can’t Predict Knee Function in Total Knee Replacement

Degree of Coronal Alignment Correction Can’t Predict Knee Function in Total Knee Replacement

Second-generation bi-cruciate stabilized total knee system has a lower reoperation and revision rate than its predecessor

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