Neutral alignment leads to higher knee society scores after total knee arthroplasty in preoperatively non-varus patients: a prospective clinical study using 3D-CT

Slevin, Omer; Hirschmann, Anna; Schiapparelli, Filippo; Amsler, Felix; Huegli, Rolf W.; Hirschmann, Michael T.

doi:10.1007/s00167-017-4744-y

Cited by 68 publications

(91 citation statements)

References 42 publications

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“…STA, SFA, mMPTA, and mLDFA belong to the angles of component alignment, while mMPTA and mLDFA determine the coronal alignments of the tibial and femoral components on the tibia and femur, respectively. Many studies [ 11 , 42 , 43 ] have proven that mMPTA and mLDFA were related to the post-operative function of the knee; our results were similar. In addition, we found that sagittal-plane component alignment, including SFA and STA, was weakly or not at all correlated with surgical outcome, similar to the findings of Antony J et al [ 21 ] DFVR was an individual anatomical characteristic and was not changed in TKA.…”

Section: Discussionsupporting

confidence: 85%

“…Previous studies have demonstrated that an appropriate angle of implantation plays a pivotal role in clinical efficacy [ 5 – 9 ]. In the previous studies, the hip–knee–ankle angle (HKA) of the lower extremity within 3° and tibial and femoral implants perpendicular to their respective anatomical axes on the sagittal plane were considered the determining factors of surgical success [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

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How to predict early clinical outcomes and evaluate the quality of primary total knee arthroplasty: a new scoring system based on lower-extremity angles of alignment

Chen

Deng

et al. 2020

BMC Musculoskelet Disord

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Background A method that can accurately predict the outcome of surgery can give patients timely feedback. In addition, to some extent, an objective evaluation method can help the surgeon quickly summarize the patient’s surgical experience and lessen dependence on the long wait for follow-up results. However, there was still no precise tool to predict clinical outcomes of total knee arthroplasty (TKA). This study aimed to develop a scoring system to predict clinical results of TKA and then grade the quality of TKA. Methods We retrospectively reviewed 98 primary TKAs performed between April 2013 and March 2017 to determine predictors of clinical outcomes among lower-extremity angles of alignment. Applying multivariable linear-regression analysis, we built Models (i) and (ii) to predict detailed clinical outcomes which were evaluated using the Knee Society Score (KSS). Multivariable logistic-regression analysis was used to establish Model (iii) to predict probability of getting a good clinical outcome (PGGCO) which was evaluated by Knee Injury and Osteoarthritis Outcome Score (KOOS) score. Finally, we designed a new scoring system consisting of 3 prediction models and presented a method of grading TKA quality. Thirty primary TKAs between April and December 2017 were enrolled for external validation. Results We set up a scoring system consisting of 3 models. The interpretations of Model (i) and (ii) were good (R 2 = 0.756 and 0.764, respectively). Model (iii) displayed good discrimination, with an area under the curve (AUC) of 0.936, and good calibration according to the calibration curve. Quality of surgery was stratified as follows: “A” = PGGCO ≥0.8, “B” = PGGCO ≤0.6 but < 0.8, and “C” = PGGCO < 0.6. The scoring system performed well in external validation. Conclusions This study first developed a validated, evidence-based scoring system based on lower-extremity angles of alignment to predict early clinical outcomes and to objectively evaluate the quality of TKA.

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

How to predict early clinical outcomes and evaluate the quality of primary total knee arthroplasty: a new scoring system based on lower-extremity angles of alignment

Chen

Deng

et al. 2020

BMC Musculoskelet Disord

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“…Malalignment of total knee arthroplasty (TKA) component positioning typically results in earlier component loosening and shortened survivorship of the prosthesis [1][2][3][4][5][6][7][8][9]. Deviations of more than 3° from neutral axis in the hip-knee-ankle axis (HKA) result in varus or valgus malalignment and are defined as 'outliers' when following an approach of classical mechanical alignment.…”

Section: Introductionmentioning

confidence: 99%

CT-based patient-specific instrumentation for total knee arthroplasty in over 700 cases: single-use instruments are as accurate as standard instruments

Gaukel

Vuille‐dit‐Bille

Schläppi

et al. 2020

Knee Surg Sports Traumatol Arthrosc

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Purpose Efforts in total knee arthroplasty are made to improve accuracy for a correct leg axis and reduce component malpositioning using patient-specific instruments. It was hypothesized that use of patient-specific instruments (vs. computernavigated and conventional techniques) will reduce the number of outliers. Our second hypothesis was that single-use instrumentation will lead to the same accuracy compared to patient-specific instruments made of metal. Methods 708 primary total knee arthroplasties between 2014 and 2018 using computer tomography (CT)-based patientspecific cutting block technique and a preoperative planning protocol were retrospectively reviewed. Preoperative data [hip-knee-angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), tibial slope, femoral component flexion] was compared to postoperative performed standard radiological follow-up X-rays. Differences of > 3° between measurements were defined as outliers. Results Overall 500 prostheses using standard instrumentation and 208 prostheses using single-use instruments were implanted. Preoperative HKA axes (− 1.2°; p < 0.001), femoral component flexion (Δ 0.8°, p < 0.001), LDFA (Δ − 1.5°, p < 0.001), MPTA (Δ − 0.5°, p < 0.001) and tibial posterior slopes (Δ 0.5°, p < 0.001), respectively, were different from postoperative axes. More outliers occurred using standard (vs. single-use) instruments (p < 0.001) regarding postoperative HKA (ranges of standard-vs. single-use: instruments: HKA 178.0°-180.5° vs. 178.0°-180.5°, femoral component flexion 0.0°-6.0° vs. 0.0°-4.5°, LDFA 90.0°-91.0° vs. 90.0°-90.0°, MPTA 90.0°-90.0° vs. 90.0°-90.0°, tibial posterior slope − 10° to 10° vs. − 1° to 10°). No differences were seen for other angles measured. Comparing both systems, total number of outliers was higher using standard (8%) vs. single-use instruments (4.3%). Conclusion This study shows a high accuracy of CT-based patient-specific instrumentation concerning postoperative achieved knee angles and mechanical leg axes. Single-use instruments showed a similar accuracy. Level of evidence III.

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“…However, when it comes to knee arthroplasty for the sake of material durability as well as simplification of instrumentation and manufacturing the pioneers of total knee arthroplasty (TKA) have made numerous assumptions, which for centuries have not been questioned as a whole. In the last years, the dogma that all knees should have a neutral hip-knee-ankle angle (HKA) after TKA has been questioned for native varus knees [11]. In addition, there is an ongoing discussion about the optimal alignment in TKA [3,5,[8][9][10].…”

mentioning

confidence: 99%

Personalised medicine in knee arthroplasty: we need more science!

Hirschmann

Friederich

Becker

et al. 2019

Knee Surg Sports Traumatol Arthrosc

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Neutral alignment leads to higher knee society scores after total knee arthroplasty in preoperatively non-varus patients: a prospective clinical study using 3D-CT

Abstract: Diagnostic study, Level II.

Cited by 68 publications

References 42 publications

How to predict early clinical outcomes and evaluate the quality of primary total knee arthroplasty: a new scoring system based on lower-extremity angles of alignment

How to predict early clinical outcomes and evaluate the quality of primary total knee arthroplasty: a new scoring system based on lower-extremity angles of alignment

CT-based patient-specific instrumentation for total knee arthroplasty in over 700 cases: single-use instruments are as accurate as standard instruments

Personalised medicine in knee arthroplasty: we need more science!

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