Skip to main content
NCBI home page
Journal of Clinical Orthopaedics and Trauma logoLink to Journal of Clinical Orthopaedics and Trauma
. 2024 Dec 12;60:102834. doi: 10.1016/j.jcot.2024.102834

The influence of the number of postoperative radiological outliers on the survival and clinical outcome of total knee arthroplasty

DMJ Theeuwen a,⁎, YFL Bemelmans a, B Boonen a, I Haveman a, W van der Weegen b, MGM Schotanus a,c
PMCID: PMC11697279  PMID: 39759465

Abstract

Introduction

After total knee arthroplasty (TKA), dissatisfaction rates are described up to 30 %. Optimal alignment of the prosthesis in TKA is believed to improve clinical outcome and survival rates. Radiological outliers after TKA are used to define this alignment. Limited evidence is available on the cumulative effect of these outliers on survival or clinical outcome. The purpose of this study is to assess whether the amount of postoperative femoral and/or tibial radiological outliers, measured in different planes, influences the survival and clinical outcome after TKA.

Methods

Prospective data were used from a previously published randomized trial, with a mean follow-up of 5-years after surgery. Data of 168 patients who received TKA were assessed. Patients were divided into four groups: 0, 1, 2 or ≥3 postoperative radiological outliers of the femoral and/or tibial component in different planes (e.g. frontal, sagittal). Revision rates were analysed and clinical outcome was assessed using PROMs. The study used a general linear model for repeated measures to compare the difference of each questionnaire over time between the groups.

Results

No statistically significant differences were found between patients with 0, 1, 2 or ≥3 outliers regarding improvement of postoperative PROMs. Data was underpowered to detect a possible relationship between the number of outliers and the survival of the prosthesis.

Conclusion

The number of postoperative radiological outliers did not influence clinical outcome after TKA. High-powered studies are needed to examine the influence of these outliers on survival rates.

Keywords: Total knee arthroplasty, Radiological outliers, Survival, Clinical outcome

1. Introduction

In the treatment of severe end-stage osteoarthritis (OA), joint replacement has proven to be one of the most successful surgical procedures.1,2,3 Over the past decades, the rate of total knee arthroplasty (TKA) has increased worldwide and is expected to grow even further.4 Nevertheless, dissatisfaction rates after TKA rise up to 30 %.5,6,7

Multiple operative techniques have been developed to achieve the best results regarding clinical outcome and survival rates of the prosthesis. Patient-specific instrumentation (PSI), computer- and robotic-assisted surgery for TKA are all developed in the pursuit of optimal alignment of the tibial and femoral components. It is believed that this optimal alignment improves clinical outcome and survival rates.8,9 Many studies have described the results of these techniques by measuring the occurrence of postoperative radiological outliers (>3° deviation from pre-operative planning).10,11,12,13,14,15,16,17 The outliers of the tibial and femoral component are measured in different planes (e.g. frontal, sagittal). Available literature on the influence of the number of these outliers combined on the clinical outcome and survival of the prosthesis is limited.

The current study is a continuation of a previously published study on the 5-years follow-up in TKA surgery. In that study, PSI was compared to conventional TKA regarding clinical outcome and survival of the prosthesis, conducted as a randomized controlled trial. This study compared the clinical outcome, in terms of PROMs, and survival of the prosthesis after TKA between patients with different amounts of postoperative radiological outliers. It was hypothesised that the cumulative number of postoperative radiological outliers negatively influences the clinical outcome and survival of TKA.

2. Methods

2.1. In this multicentre prospective study, data was used from the 5-years follow-up of a previously published study.17,18 The primary study was approved by the institutional review boards of both hospitals (File nr. 10-T-21) and informed consent from all patients was obtained. This randomized, double-blind controlled trial compared TKA procedures with use of PSI to the conventional surgical method. A total of 180 patients were enrolled between September 2010 and March 2013 at the Zuyderland Medical Center (Sittard-Geleen, the Netherlands) and St. Anna Hospital (Geldrop, the Netherlands). Inclusion criteria were patients with disabling osteoarthritis of the knee, candidate for total knee arthroplasty. Exclusion criteria were osteosynthesis or other metal near the knee, ankle or hip joint, the inability to undergo an MRI-scan and previous knee surgery (except arthroscopic meniscectomy). The same cemented cruciate retaining implant was used in both groups (Vanguard TKA System, Zimmer Biomet Orthopaedics, Warsaw, IN, USA). All procedures were performed by experienced orthopaedic knee surgeons with >10 years of experience with conventional TKA who performed at least 100 TKA's using PSI.

For all patients the position of the prosthesis was planned pre-operatively. In the frontal plane the goal was to obtain a neutral mechanical axis and neutral position of the femoral and tibial components (90° cut to mechanical axis of both femur and tibia). When using PSI, a femoral flexion and posterior slope of 3° was obtained in the sagittal plane. When using conventional TKA, femoral flexion and posterior slope were set at 0°.17

Six-weeks postoperatively, all patients received weight bearing AP long-leg radiographs and standard lateral radiographs. On the long-leg radiographs, deviations of more than 3° from a neutral mechanical axis (180°) and more than 3° varus or valgus position of the tibial or femoral component were regarded as outliers. On the lateral radiographs, values that differ more than 3° from pre-operatively planned femoral flexion and posterior slope were regarded as an outlier.

In this current study patients were allocated to different groups, based on the cumulative number of postoperative radiologic outliers. The first group consisted of patients with no radiological outliers. The second, third and fourth group consisted of patients with 1, 2 or ≥3 radiological outliers, respectively. To measure clinical outcome after TKA all patients completed the questionnaires described below pre-operatively, at 3 months follow-up and at 1-, 2- and 5-years follow-up. First the Dutch version of the Oxford Knee Score (OKS) scored from 12 to 60, with 12 being the best possible outcome and 60 being the worst possible outcome.19 Second, the Dutch version of the Western Ontario and McMaster osteoarthritis index (WOMAC) scored from 0 to 100 with 0 being the worst outcome and 100 being the best outcome.20 Next a visual analogue scale (VAS-pain) for pain 21 and the EuroQol (EQ-5D, 3L version).22 For the EQ-5D a single summary index was used. An index of 1 represents perfect health. To assess survival of the prosthesis, patients’ files were checked if revision surgery was performed.

2.1. Statistical analysis

The analyses were performed with the use of SPSS (IBM statistics version 25.0). An ANOVA test was done to determine if there was a difference between the groups pre-operatively. Thereafter, a general linear model for repeated measurements was used to examine if there was a difference over time between the different groups for each questionnaire. P-values <0.05 were considered statistically significant.

3. Results

In this current study we used data from the 5-years follow-up of a previous RCT.17 Measurement method of outliers on radiographs was described in the previous article. Patients’ characteristics including the occurrence of the number of outliers are described in Table 1. Table 1 also shows that most outliers were measured in the sagittal plane for both femoral and tibial component. Lost to follow-up of this trial was described in the previous article.18 Loss to follow-up for the specific groups in the current study was 1 patient in the group with no outliers, 3 patients in the group with 1 outlier, 3 patients in the group with two outliers and 2 in the group with ≥3 outliers. Finally, 168 patients were included in this study. There was no statistically significant difference over time between the groups for each questionnaire assessed (Table 2). Results for each questionnaire are presented separately in Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5.

Table 1.

patient characteristics.

Participants 168
Men:women (%) 66:102 (39:61 %)
Mean age 71.8 (range 52.5–87.6)
Mean follow-up 4.6 years (range 4.4–4.8)
Number of outliers per patient (%) Patients with 0 outliers 40 (24 %)
Patients with 1 outlier 55 (33 %)
Patients with 2 outliers 49 (29 %)
Patients with ≥3 outliers 24 (14 %)
Outliers per radiological outcome (%) HKA 49 (21 %)
FFC 28 (12 %)
FTC 13 (6 %)
LFC 80 (35 %)
LTC 60 (26 %)
Open in a new tab

HKA = hip knee angle. FFC = frontal femoral component. FTC = frontal tibial component. LFC = lateral femoral component. LTC = lateral tibial component.

Table 2.

Significance of difference in number of outliers over time, statistically significant different when p < 0.05

PROMs N Significance of difference over time between groups (statistically significant different when p < 0.05)
WOMAC 138 0.436
OKS 137 0.174
VAS-pain 143 0.368
EQ 5D 136 0.233
EQ (5D)-VAS 135 0.223
Open in a new tab

WOMAC = Western Ontario and McMaster Universities Osteoarthritis Index. OKS = Oxford Knee Score. VAS = Visual Analogue Scale. EQ (5D) = Euroqol 5D.

Fig. 1.

Fig. 1

Open in a new tab

Scores on WOMAC for each group over time.

Fig. 2.

Fig. 2

Open in a new tab

Scores on OKS for each group over time.

Fig. 3.

Fig. 3

Open in a new tab

Scores on VAS for each group over time.

Fig. 4.

Fig. 4

Open in a new tab

Scores on EQ5D for each group over time.

Fig. 5.

Fig. 5

Open in a new tab

Scores on EQ5D-VAS for each group over time.

At final follow-up, 5-years postoperatively, a total of 4 patients had undergone revision surgery. Two patients in the group with 1 outlier; one revision of the tibial component to one size smaller due to lateral knee pain and one placement of a patella button for patellofemoral complains. The other two patients underwent revision due to persistent knee pain, one in the group with 2 outliers and one in the group with 3 outliers. No revisions were performed due to instability of the knee joint.

4. Discussion

The main finding of this study is that the cumulative number of postoperative radiological outliers does not influence clinical outcome after TKA over time. No statistically significant differences were found over time for any of the PROMs between the different groups. In our population, rate of revision was low and therefore underpowered to assess the influence of the number of outliers on the survival of the prosthesis.

Although this study showed no statistically significant difference over time for any of the PROMs, it is remarkable that for the WOMAC, EQ-5D and EQ-5D-VAS the group with no outliers shows better results up to 2-years follow-up compared to the other groups. At 5-years follow-up, this difference is no longer visible. An explanation could be that improvement after TKA is most seen up to one or two years postoperatively with relatively unchanged improvement up to 5-years.23,24,25 This suggests that TKA with fewer outliers leads to a different postoperative improvement of clinical outcome.

To the best of our knowledge, there are no previous studies that describe the influence of the cumulative number of different radiological outliers in one and the same patient. However, a few studies assessed the influence of one outlier on clinical outcome. Within these studies, the influences of radiological outliers on clinical outcome were limited. For example, varus alignment of >3°, measured in the frontal plane, was found to not negatively influence clinical outcome.26,27 The results were obtained by measuring only mechanical long leg axis and not the femoral and tibia component, as done in the present study. Besides, both studies divided their study population in multiple groups which led to relatively small groups and could therefore influence outcome due to underpowered sample size. Nevertheless, the current study reports equal results regarding varus alignment and clinical outcome. Previous studies found that increased femoral flexion, measured in the sagittal plane, could lead to dissatisfaction rates and possible flexion contracture whereas extension of the femoral component could lead to anterior knee pain 28,29 Although these differences were not statistically significant different, adequate positioning of the femoral component in the sagittal plane is still of crucial importance to prevent for unsatisfactory results.

Regarding the influence of radiological outliers of the tibial component on clinical outcome for the sagittal plane, one study suggest one study suggests that decreased tibial slope can lead to decreased range of motion.30 Another study reported that maintaining native posterior slope within 4° correlates with superior PROMs.31

Compared to the current study, we only found one previous study that examined the influence of different outliers combined on clinical outcome. For each plane, the height of the outlier in degrees was determined. These numbers were added up which led to the cumulative error of all outliers. Trends were identified for better function with good sagittal and coronal tibial alignment while low cumulative error leads to better clinical outcome. The difference with the current study is that the cumulative error of the different planes was assessed, while we assessed the cumulative number of planes that have an outlier. Limitations were that only one measurement tool (KSS) was used to assess clinical outcome.32

Regarding survival of the prosthesis, the present study was underpowered. Nevertheless, the reported revisions were seen in all the outlier groups (1, 2 and > 3 outliers respectively). A review of the literature concluded that a neutral mechanical axis remains the optimal guide to alignment of TKA, suggesting that adequate positioning is crucial to prevent for revisions.33,34 When analysing in detail the role of varus alignment, higher failure rates were found for varus alignment less than 0° and more than 3°. Reports on valgus outliers showed no statistically significant differences on clinical outcome or revision rate.35,36 As present in our study, 4 patients underwent revision surgery where 3 patients had an outlier of the femoral component in the sagittal plane, namely increased femoral flexion. In the previous literature, for the sagittal plane only one study stated that a femoral alignment of 0–3° and tibial slope of 0–7° leads to a decreased revision rate.37

In the current study we only used PROMs to assess clinical outcome. Controversy exists whether PROMs are the most reliable method to evaluate clinical outcome of TKA.38 A recurring limitation is the fact that a large number of the PROMs that are currently used lack essential evidence of their measurement properties. Previous studies also described that the limitation of PROMs can be a result of the ceiling effects.39 Besides PROMs, forgotten joint score (FJS-12) is increasingly used to measure patient satisfaction after TKA surgery. When comparing TKA to total hip arthroplasty (THA), TKA patients reported remarkably lower FJS-12 scores.40 Considering these outcomes, it underlines the importance of understanding more about the causes of unsatisfying results after TKA where dissatisfaction rates up to 30 percent are described.41High variation exists between studies in the assessment of clinical and functional outcome after TKA. Although PROMs are the most commonly adopted outcome measure, performance-based outcome measures, for example range of motion and 6-min-walk test, can be of added value.42

The main advantage of the current study is that by our knowledge no previous study assessed the influence of the number of outliers in multiple planes in a RCT. Limitations of this study were the retrospective setting and the fact that the study was underpowered to assess a significant difference in revision rate. This can be explained by the fact that data from a previous published study were used.17,18 This study was powered in order to assess a different hypothesis and using data from a previous study can therefor be considered as a limitation.

Larger study populations are needed to assess the influence of the number of outliers on the survival of the prosthesis. Since several studies describe a statistically significant relationship between an outlier and the survival of the prostheses, it can be argued that this relationship might even be more pronounced for the cumulative number of outliers. Longer follow-up is therefore mandatory.

5. Conclusions

The cumulative number of postoperative radiological outliers did not influence clinical outcome after TKA. Higher-powered studies are needed to examine the influence of these outliers on survival rates.

Author contribution

D.M.J. Theeuwen MD: Conceptualization, methodololy, validation, formal analysis, resources, data curation, writing – original draft, project administration. Y.F.L. Bemelmans MSc: writing – review & editing. B. Boonen MD, PhD: writing – review & editing. I. Haveman BSc: writing – review & editing. W. van der Weegen PhD: writing – review & editing. M.G.M. Schotanus PhD: conceptualization, writing – review & editing, visualization, supervision.

Declaration of competing interest

The authors declare that they have no competing interests to declare.

Contributor Information

D.M.J. Theeuwen, Email: d.theeuwen@zuyderland.nl.

Y.F.L. Bemelmans, Email: yo.bemelsmans@zuyderland.nl.

B. Boonen, Email: be.boonen@zuyderland.nl.

I. Haveman, Email: i.haveman@outlook.com.

W. van der Weegen, Email: w.vander.weegen@st-anna.nl.

M.G.M. Schotanus, Email: m.schotanus@zuyderland.nl.

References

  • 1.Jüni P., Reichenbach S., Dieppe P. Osteoarthritis: rational approach to treating the individual. Best Pract Res Clin Rheumatol. 2006;20(4):721–740. doi: 10.1016/j.berh.2006.05.002. [DOI] [PubMed] [Google Scholar]
  • 2.Bin G., Jinmin L., Cong T., Yuchen T., Xiaohui Z., Yayi X. Surgical interventions for symptomatic knee osteoarthritis: a network meta-analysis of randomized control trials. BMC Musculoskelet Disord. 2023;24(1):313. doi: 10.1186/s12891-023-06403-z. 22. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Price A.J., Alvand A., Troelsen A., et al. Knee replacement. Lancet. 2018;392(10158):1672–1682. doi: 10.1016/S0140-6736(18)32344-4. [DOI] [PubMed] [Google Scholar]
  • 4.Singh J.A. Epidemiology of knee and hip arthroplasty: a systematic review. Open Orthop J. 2011;5(1):80–85. doi: 10.2174/1874325001105010080. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Williams D.P., O'Brien S., Doran E., et al. Early postoperative predictors of satisfaction following total knee arthroplasty. Knee. 2013;20(6):442–446. doi: 10.1016/j.knee.2013.05.011. [DOI] [PubMed] [Google Scholar]
  • 6.DeFrance M.J., Scuderi G.R. Are 20% of patients actually dissatisfied following total knee arthroplasty? A Systematic Review of the Literature. J Arthroplasty. 2023;38(3):594–599. doi: 10.1016/j.arth.2022.10.011. [DOI] [PubMed] [Google Scholar]
  • 7.Rodriguez-Merchan E.C. Patients satisfaction following primary total knee arthroplasty: contributing factors. Arch Bone Jt Surg. 2021;9(4):179–386. doi: 10.22038/abjs.2020.46395.2274. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Fang D.M., Ritter M.A., Davis K.E. Coronal alignment in total knee arthroplasty: just how important is it? J Arthroplasty. 2009;24(6 Suppl):39–43. doi: 10.1016/j.arth.2009.04.034. [DOI] [PubMed] [Google Scholar]
  • 9.Dossett H.G., Arthur J.R., Makovicka J.L., et al. A randomized controlled trial of kinematically and mechanically aligned total knee arthroplasties: long-term follow-up. J Arthroplasty. 2023;38(6S):S209–S214. doi: 10.1016/j.arth.2023.03.065. [DOI] [PubMed] [Google Scholar]
  • 10.Mattei L., Pellegrino P., Calo M., Bistolfi A., Castoldi F. Patient specific instrumentation in total knee arthroplasty: a state of the art. Ann Transl Med. 2016;4(7):126. doi: 10.21037/atm.2016.03.33. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Sassoon A., Nam D., Nunley R., Barrack R. Systematic review of patient-specific instrumentation in total knee arthroplasty: new but not improved. Clin Orthop Relat Res. 2015;473(1):151–158. doi: 10.1007/s11999-014-3804-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Yamamura K., Minoda Y., Sugama R., et al. Design improvement in patient-specific instrumentation for total knee arthroplasty improved the accuracy of tibial prosthetic alignment in the coronal and axial planes. Knee Surg Sports Traumatol Arthrosc. 2020;28(5):1560–1567. doi: 10.1007/s00167-019-05571-7. [DOI] [PubMed] [Google Scholar]
  • 13.Haritinian E.G., Pimpalnerkar A.L. Computer assisted total knee arthroplasty: does it make a difference? Maedica (Buchar) 2013;8(2):176–181. DOI not available. [PMC free article] [PubMed] [Google Scholar]
  • 14.Alessio B., Norberto C. Computer-assisted surgery in total knee replacement: advantaged, surgical procedure and review of the literature. Acta Biomed. 2019;90(1):16–23. doi: 10.23750/abm.v90i1.6319. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Aflatooni J.O., Wininger A.E., Park K.J., Incavo S.J. Alignment options and robotics in total knee arthroplasty. Front Surg. 2023;10 doi: 10.3389/fsurg.2023.1106608. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Ren Y., Cao S., Wu J., Weng X., Feng B. Efficacy and reliability of active robotic-assisted total knee arthroplasty compared with conventional total knee arthroplasty: a systematic review and meta-analysis. Postgrad Med J. 2019;95(1121):125–133. doi: 10.1136/postgradmedj-2018-136190. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Boonen B., Schotanus M.G., Kerens B., van der Weegen W., van Drumpt R.A., Kort N.P. Intra-operative results and radiological outcome of conventional and patient-specific surgery in total knee arthroplasty: a multicentre, randomised controlled trial. Knee Surg Sports Traumatol Arthrosc. 2013;21(10):2206–2212. doi: 10.1007/s00167-013-2620-y. [DOI] [PubMed] [Google Scholar]
  • 18.Schotanus M.G.M., Boonen B., van der Weegen W., et al. No difference in mid-term survival and clinical outcome between patient-specific and conventional instrumented total knee arthroplasty: a randomized controlled trial. Knee Surg Sports Traumatol Arthrosc. 2019;27(5):1463–1468. doi: 10.1007/s00167-018-4968-5. [DOI] [PubMed] [Google Scholar]
  • 19.Haverkamp D., Breugem S.J., Sierevelt I.N., Blankevoort L., van Dijk C.N. Translation and validation of the Dutch version of the Oxford 12-item knee questionnaire for knee arthroplasty. Acta Orthop. 2005;76(3):347–352. DOI not available. [PubMed] [Google Scholar]
  • 20.Bellamy N., Buchanan W.W., Goldsmith C.H., Campbell J., Stitt L.W. Validation study of WOMAC: a health status instrument for measuring clinically important patient relevant outcomes to anti-rheumatic drug therapy in patients with osteoarthritis of the hip or knee. J Rheumatol. 1988;15(12):1833–1840. DOI not available. [PubMed] [Google Scholar]
  • 21.Freyd M. The graphic rating scale. J Educ Psych. 1923;14(2):83–102. doi: 10.1037/h0074329. [DOI] [Google Scholar]
  • 22.EuroQol Group EuroQol - a new facility for the measurement of health-related quality of life. Health Pol. 1990;16(3):199–208. doi: 10.1016/0168-8510(90)90421-9. [DOI] [PubMed] [Google Scholar]
  • 23.Jauregui J.J., Issa K., Cherian J.J., Harwin S.F., Given K., Mont M.A. Evaluation of 5-year trends in knee society scores stratified by comorbidities: a prospective, longitudinal study. J Knee Surg. 2016;29(1):84–90. doi: 10.1055/s-0035-1544192. [DOI] [PubMed] [Google Scholar]
  • 24.Carlson V.R., Post Z.D., Orozco F.R., Davis D.M., Lutz R.W., Ong A.C. When does the knee feel normal again: a cross-sectional study assessing the forgotten joint score in patients after total knee arthroplasty. J Arthroplasty. 2018;33(3):700–703. doi: 10.1016/j.arth.2017.09.063. [DOI] [PubMed] [Google Scholar]
  • 25.Piuzzi N.S., Cleveland clinic O.M.E. Arthroplasty group Patient-reported outcomes at 1 and 2 years after total hip and knee arthroplasty: what is the minimum required follow-up? Arch Orthop Trauma Surg. 2022;142(9):2121–2129. doi: 10.1007/s00402-021-03819-x. [DOI] [PubMed] [Google Scholar]
  • 26.Salzmann M., Fennema P., Becker R., Hommel H. Does postoperative mechanical Axis alignment have an effect on clinical outcome of primary total knee arthroplasty? A retrospective cohort study. Open Orthop J. 2017;11(1):1330–1336. doi: 10.2174/1874325001711011330. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Nishida K., Matsumoto T., Takayama K., et al. Remaining mild varus limb alignment leads to better clinical outcome in total knee arthroplasty for varus osteoarthritis. Knee Surg Sports Traumatol Arthrosc. 2017;25(11):3488–3494. doi: 10.1007/s00167-016-4260-5. [DOI] [PubMed] [Google Scholar]
  • 28.Okamoto Y., Otsuki S., Nakajima M., Jotoku T., Wakama H., Neo M. Sagittal alignment of the femoral component and patient height are associated with persisting flexion contracture after primary total knee arthroplasty. J Arthroplasty. 2019;34(7):1476–1482. doi: 10.1016/j.arth.2019.02.051. [DOI] [PubMed] [Google Scholar]
  • 29.Scott C.E.H., Clement N.D., Yapp L.Z., MacDonald D.J., Patton J.T., Burnett R. Association between femoral component sagittal positioning and anterior knee pain in total knee arthroplasty: a 10-year case-control follow-up study of a cruciate-retaining single-radius design. J Bone Joint Surg Am. 2019;101(17):1575–1585. doi: 10.2106/JBJS.18.01096. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.Malviya A., Lingard E.A., Weir D.J., Deehan D.J. Predicting range of movement after knee replacement: the importance of posterior condylar offset and tibial slope. Knee Surg Sports Traumatol Arthrosc. 2009;17(5):491–498. doi: 10.1007/s00167-008-0712-x. [DOI] [PubMed] [Google Scholar]
  • 31.Farooq H., Deckard E.R., Carlson J., Ghattas N., Meneghini R.M. Coronal and sagittal component position in contemporary total knee arthroplasty: targeting native alignment optimizes clinical outcome. J Arthroplasty. 2023 doi: 10.1016/j.arth.2023.04.040. [DOI] [PubMed] [Google Scholar]
  • 32.Longstaff L.M., Sloan K., Stamp N., Scaddan M., Beaver R. Good alignment after total knee arthroplasty leads to faster rehabilitation and better function. J Arthroplasty. 2009;24(4):570–578. doi: 10.1016/j.arth.2008.03.002. [DOI] [PubMed] [Google Scholar]
  • 33.Liu H.X., Shang P., Ying X.Z., Zhang Y. Shorter survival rate in varus-aligned knees after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2016;24(8):2663–2671. doi: 10.1007/s00167-015-3781-7. [DOI] [PubMed] [Google Scholar]
  • 34.Weber P., Gollwitzer H. Kinematic alignment in total knee arthroplasty. Oper Orthop Traumatol. 2021;33(6):525–537. doi: 10.1007/s00064-021-00729-4. [DOI] [PubMed] [Google Scholar]
  • 35.Lee B.S., Cho H.I., Bin S.I., Kim J.M., Jo B.K. Femoral component varus malposition is associated with tibial aseptic loosening after TKA. Clin Orthop Relat Res. 2018;476(2):400–407. doi: 10.1007/s11999.00000000000000.12. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Abdel M.P., Oussedik S., Parratte S., Lustig S., Haddad F.S. Coronal alignment in total knee replacement: historical review, contemporary analysis, and future direction. Bone Joint Lett J. 2014;96-B(7):857–862. doi: 10.1302/0301-620X.96B7.33946. [DOI] [PubMed] [Google Scholar]
  • 37.Kim Y.-H., Park J.-W., Kim J.-S. The relationship between the survival of total knee arthroplasty and postoperative coronal, sagittal and rotational alignment of knee prosthesis. Int Orthop. 2014;38(2):379–385. doi: 10.1007/s00264-013-2097-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 38.Gagnier J.J., Mullins M., Huang H., et al. A systematic review of measurement properties of patient-reported outcome measures used in patients undergoing total knee arthroplasty. J Arthroplasty. 2017;32(5):1688–1697.e7. doi: 10.1016/j.arth.2016.12.052. [DOI] [PubMed] [Google Scholar]
  • 39.Harris K., Dawson J., Gibbons E., et al. Systematic review of measurement properties of patient-reported outcome measures used in patients undergoing hip and knee arthroplasty. Patient Relat Outcome Meas. 2016;7:101–108. doi: 10.2147/PROM.S97774. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.Puliero B., Beaulieu Y., Vendittoli P.A. Joint perception after total hip arthroplasty and the forgotten joint. J Arthroplasty. 2019;34(1):65–70. doi: 10.1016/j.arth.2018.09.086. [DOI] [PubMed] [Google Scholar]
  • 41.Williams D.P., Price A.J., Beard D.J., et al. The effects of age on patient-reported outcome measures in total knee replacements. Bone Joint Lett J. 2013;95-B(1):38–44. doi: 10.1302/0301-620X.95B1.28061. [DOI] [PubMed] [Google Scholar]
  • 42.Adriani M., Becker R., Milano G., Lachowski K., Prill R. High variation among clinical studies in the assessment of physical function after knee replacement: a systematic review. Knee Surg Sports Traumatol Arthrosc. 2023;31(9):3854–3860. doi: 10.1007/s00167-023-07375-2. Epub 2023 Mar 13. PMID: 36907938; PMCID: PMC10435639. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of Clinical Orthopaedics and Trauma are provided here courtesy of Elsevier

RESOURCES