
==== Front
J Exp Orthop
J Exp Orthop
10.1002/(ISSN)2197-1153
JEO2
Journal of Experimental Orthopaedics
2197-1153
John Wiley and Sons Inc. Hoboken

10.1002/jeo2.70014
JEO270014
Original Paper
Original Paper
Temporal changes in tibiofemoral relationship following anterior cruciate ligament injury: Implications for rotational dynamics and clinical outcomes
Okimura Shinichiro http://orcid.org/0000-0002-3767-7344
1 shinichirookimura@gmail.com

Suzuki Tomoyuki 2
Ikeda Yasutoshi 3
Shiwaku Kousuke 3
Hamaoka Kodai 1
Horita Kazushi 3
Teramoto Atsushi 3
1 Department of Orthopaedic Surgery Obihiro Kyokai Hospital Obihiro Hokkaido Japan
2 Department of Orthopaedic Surgery Sapporo Maruyama Orthopaedic Hospital Sapporo Hokkaido Japan
3 Department of Orthopaedic Surgery Sapporo Medical University School of Medicine Sapporo Hokkaido Japan
* Correspondence Shinichiro Okimura, Department of Orthopaedic Surgery, Obihiro Kyokai Hospital, 2, East‐5, South‐9, Obihiro, Hokkaido 080‐0805, Japan.
Email: shinichirookimura@gmail.com

09 9 2024
7 2024
11 3 10.1002/jeo2.v11.3 e7001426 5 2024
10 7 2024
© 2024 The Author(s). Journal of Experimental Orthopaedics published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.
https://creativecommons.org/licenses/by/4.0/ This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

This study aims to elucidate changes in the tibiofemoral relationship over time following anterior cruciate ligament (ACL) injury, and investigate the correlation between the tibiofemoral relationship and patient‐related outcome measures (PROMs).

Methods

Overall, 203 primary ACL reconstructions were performed using autologous hamstring grafts. Medial and lateral anterior tibial translation (ATT) in the sagittal plane and tibial tubercle‐trochlear groove (TT‐TG) distance in the axial plane were measured using pre‐operative magnetic resonance imaging and post‐operative computed tomography. The difference between pre‐operative and post‐operative values for each parameter was calculated: ΔMesdial ATT, ΔLateral ATT and ΔTT‐TG distance. The correlation between each calculated value and the time elapsed since ACL injury, and the correlation between each calculated value and PROMs—evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS)—were assessed.

Results

Sixty‐four patients were enroled. Medial ATT, lateral ATT and TT‐TG distance were significantly different pre‐operatively compared to post‐operative values, with the tibia translating anteriorly and rotating internally relative to the femur. ΔMedial ATT, ΔLateral ATT and ΔTT‐TG distance were 1.6, 8.8 and −4.8 mm, respectively. A negative correlation was observed between the ΔTT‐TG distance and the time elapsed since the injury (r = −0.44, p < 0.01). No correlation was found between ΔMedial ATT and the time elapsed since the injury, nor between ΔLateral ATT and the time elapsed since the injury. Neither the ΔMedial ATT, ΔLateral ATT, nor ΔTT‐TG distance correlated with the pre‐operative or post‐operative KOOS subscale scores.

Conclusions

The tibia underwent internal rotation relative to the femur over time following ACL injury, highlighting the importance of assessing rotational changes in ACL‐injured knees.

Level of Evidence

Level Ⅲ.

ACL
anterior tibial translation
chronicity of ACL deficiency
tibial rotation
source-schema-version-number2.0
cover-dateJuly 2024
details-of-publishers-convertorConverter:WILEY_ML3GV2_TO_JATSPMC version:6.4.8 mode:remove_FC converted:09.09.2024
Okimura, S. , Suzuki, T. , Ikeda, Y. , Shiwaku, K. , Hamaoka, K. , Horita, K. et al. (2024) Temporal changes in tibiofemoral relationship following anterior cruciate ligament injury: Implications for rotational dynamics and clinical outcomes. Journal of Experimental Orthopaedics, 11 , e70014. 10.1002/jeo2.70014
==== Body
pmcAbbreviations

ACL anterior cruciate ligament

ACLR ACL reconstruction

ATT anterior tibial translation

CT computed tomography

KOOS Knee Injury and Osteoarthritis Outcome Score

MRI magnetic resonance imaging

PROM patient‐related outcome measure

TT‐TG tibial tubercle‐trochlear groove

INTRODUCTION

Anterior cruciate ligament (ACL) injuries are the most prevalent knee ligament injuries. The ACL plays a crucial role in maintaining a normal tibiofemoral relationship, preventing anterior translation and preserving knee rotational stability. Previous studies have highlighted distinctions in the tibiofemoral relationship between knees with ACL deficiency and those with intact ACLs [16, 29]. Notably, prolonged ACL deficiency can lead to an abnormal tibiofemoral relationship, potentially resulting in meniscus injury, cartilage damage and osteoarthritis progression [16].

It is widely recognized that ACL deficiency leads to a change in the tibiofemoral relationship within the knee joint [20]. The chronicity of ACL deficiency affects the tibiofemoral relationship in the sagittal plane, resulting in anterior translation of the tibia relative to the femur [16, 32]. Despite the extensive examination of anterior tibial translation (ATT) in the sagittal plane, there has been limited scrutiny of tibial rotation in the axial plane, while the tibia would theoretically also rotate in ACL‐deficient knees [3, 16, 19, 32].

The tibial tubercle‐trochlear groove (TT‐TG) distance, a well‐established parameter for evaluating patellar instability, reflects the amount of knee rotation [11, 35]. The TT‐TG distance was defined as the offset distance between the deepest point of the trochlear groove and the centre of the patellar tendon insertion on the tibial tuberosity assessed in the axial plane [17, 28]. Recent studies have identified the TT‐TG distance as a risk factor for both native ACL injury and graft failure following ACL reconstruction [14, 29]. However, to the best of our knowledge, no study has systematically investigated sequential tibiofemoral changes in the TT‐TG distance over time following ACL injury.

The objectives of this study were twofold: (1) to elucidate the changes in the tibiofemoral relationship over time following ACL injury, with a specific focus on the axial plane; and (2) to investigate the correlation between the tibiofemoral relationship and patient‐related outcome measures (PROMs). It was hypothesized that (1) the tibia would undergo anterior and internal translocation over time following an ACL injury, and (2) patients with significant translocation would experience worse PROMs.

MATERIALS AND METHODS

This study was approved by the Institutional Review Board (approval number: 282‐215). Informed consent was obtained from all participants.

Patients

Between 2013 and 2022, 203 primary ACL reconstructions (ACLR) using autologous hamstring grafts were performed at our hospital. Patients who (1) underwent primary isolated ACLR, (2) undertook magnetic resonance imaging (MRI) within 1 year after trauma and (3) undertook computed tomography (CT) 1 week post‐operatively were included. We excluded patients with (1) meniscus injury, (2) unclear history of trauma, (3) multiple ligament injuries, (4) prior knee surgery and (5) insufficient data (Figure 1).

Figure 1 Flowchart of patient selection.

Surgical technique and post‐operative rehabilitation

Anatomic triple‐bundle or double‐bundle ACLR was performed with autologous hamstring tendon grafts as described previously [30]. The meniscus was arthroscopically assessed during ACLR. The graft was fixed with Endobutton‐CL (Smith & Nephew Endoscopy) on the femur, whereas double‐spike plates (Meira Corp.) and screws were used on the tibial side, with an initial tension of 20 N at 15°–20° of knee flexion.

Post‐operatively, the knee was splint immobilized in a slightly flexed position. Range of motion exercises commenced 1 week post‐operatively. Partial weight bearing was permitted at 2 weeks, followed by full weight bearing at 3–4 weeks. Jogging was allowed at 3–4 months, and patients could return to sports activities between 6 and 8 months.

Radiological evaluation

Pre‐operative MRI and post‐operative CT were performed on all patients. MRI images were obtained using a Canon Vantage 3.0‐Tesla and a quadrature detection coil (field of view, 160 mm; matrix, 368 × 224; slice thickness, 5.0 mm; interslice gap, 1 mm; receiver bandwidth, 224 kHz; repetition time, 500 ms; echo time, 10 ms). CT scans were obtained with the knee splint immobilized using a Canon Aquilion ONE (spiral scan, 0.5‐mm slice thickness).

ATT was assessed using sagittal sequences (Figure 2). The ATT was defined as the distance between the vertical line drawn to the posterior edge of the femoral condyle and the vertical line drawn to the posterior edges of the tibial plateau [34]. A positive value indicated an anterior translation of the tibia relative to the femur.

Figure 2 Measurement of the anterior tibial translation (ATT) on magnetic resonance imaging (MRI) and computed tomography (CT). The ATT is assessed using sagittal sequences. It is defined as the distance between the vertical line drawn to the posterior edge of the centre of each femoral condyle (dashed line) and the vertical line drawn to the posterior edges of each tibial plateau (dotted line). A positive value indicates the anterior translation of the tibia relative to the femur (arrow). (a) Measurement of medial ATT on MRI. (b) Measurement of lateral ATT on MRI. (c) Measurement of medial ATT on CT. (d) Measurement of lateral ATT on CT.

TT‐TG distance, defined as the offset distance between the deepest point of the trochlear groove and the centre of the patellar tendon insertion on the tibial tuberosity, was assessed using axial sequences (Figure 3) [28]. The posterior point of the medial and lateral condyles of the femur was defined as the reference line. A line perpendicular to the reference line was drawn through the deepest bony point of the trochlear groove. A second line perpendicular to the reference line was drawn through the most anterior point of the tibial tuberosity on the axial section, showing the most anterior point of the tuberosity. The TT‐TG distance was defined as the distance between two perpendicular lines. A positive value indicated external rotation of the tibia relative to the femur.

Figure 3 Measurement of tibial tubercle‐trochlear groove (TT‐TG) distance on magnetic resonance imaging (MRI) and computed tomography (CT). The TT‐TG distance is assessed using axial sequences. It is defined as the offset distance between the deepest point of the trochlear groove and the centre of the patellar tendon insertion on the tibial tuberosity. The most posterior point of the medial and lateral condyles of the femur is defined as the reference line (solid line). A line perpendicular to the reference line is drawn through the deepest bony point of the trochlear groove (dotted line). A second line perpendicular to the reference line is drawn through the most anterior point of the tibial tuberosity on the axial section, showing the most anterior point of the tuberosity (dashed line). The TT‐TG distance is defined as the distance between these two perpendicular lines (arrow). A positive value indicates external rotation of the tibia relative to the femur. (a) Measurement of TT‐TG distance on MRI. (b) Measurement of TT‐TG distance on CT.

Intraclass correlation coefficients (ICCs) were determined to assess the intra‐ and interobserver reproducibility. To assess intraobserver variations, all parameters were measured repeatedly by one observer 8 weeks later. To assess interobserver reliability, two independent blinded observers remeasured the subjects. The intra‐ and interobserver reliabilities for assessing radiological measurements showed substantial agreement, with ICC values >0.7.

The post‐operative medial ATT, lateral ATT and TT‐TG distances were established as baseline values for each patient. The difference between the pre‐operative and post‐operative values for each parameter was calculated: ΔMedial ATT, ΔLateral ATT and ΔTT‐TG distance. The correlation between each calculated value and the time elapsed since the ACL injury was assessed.

Clinical evaluation

The clinical evaluation consisted of physical examination and PROMs. Knee joint laxity was assessed through the Lachman and pivot shift tests. The Lachman test was graded as negative, trace or positive. The pivot shift test was graded as negative, glide, clunk or gross, according to the International Knee Documentation Committee evaluation form [12]. Anterior laxity was quantified using a KT‐1000 arthrometer (MED Metrics). PROMs were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) [26]. The correlation between each calculated value and the KOOS subscales was assessed.

Statistical analysis

Statistical analyses were performed using EZR (version 1.61; Saitama Medical Center, Jichi Medical University), a graphical interface for R (version 4.2.2.; R Foundation for Statistical Computing) [13].

Correlations were examined using Spearman's rank correlation test. Continuous variables were analysed using a paired t test. Statistical significance was defined as p values <0.05.

A priori power analysis was performed to determine an appropriate sample size using G*Power version 3.1.0 (Heinrich Heine University, Duesseldorf, Germany). A sample size of 42 patients would provide a statistical power of 0.95 at a significance level (alpha) of 0.05, with an effect size of 0.50.

RESULTS

Sixty‐four patients were enroled in this study; their demographic characteristics are shown in Table 1. The medial ATT, lateral ATT and TT‐TG distances were significantly different pre‐operatively compared to post‐operative values (p < 0.01 for all), with the tibia translated anteriorly and rotated internally relative to the femur (Table 2). The ΔMedial ATT and ΔLateral ATT were 1.6 and 8.8 mm, respectively. No correlation was found between ΔMedial ATT and the time elapsed since the injury, nor between ΔLateral ATT and the time elapsed since the injury (Figures 4 and 5). The ΔTT‐TG distance was −4.8 mm. A negative correlation was observed between the ΔTT‐TG distance and the time elapsed since the injury (r = −0.44, p < 0.01) (Figure 6). Table 3 provides a summary of post‐operative physical examinations. All KOOS subscale scores improved significantly post‐operatively (Table 4). Neither the ΔMedial ATT, ΔLateral ATT, nor ΔTT‐TG distance correlated with the pre‐operative or post‐operative KOOS subscale scores.

Table 1 Patient characteristics.

Age, years	26.7 ± 14.0	
Sex, n, male/female	35/29	
BMI, kg/m2	22.5 ± 3.8	
Time elapsed from injury to MRI, days	17.7 ± 28.3	
Follow‐up period, months	27.6 ± 18.0	
Note: All data expressed as mean ± standard deviation

Abbreviations: BMI, body mass index; MRI, magnetic resonance imaging.

John Wiley & Sons, Ltd.

Table 2 Imaging measurements.

	Pre‐operative	Post‐operative	Δ	p Value	
Medial ATT, mm	0.4 ± 2.8	−1.2 ± 2.4	1.6 ± 2.6	<0.01	
Lateral ATT, mm	5.3 ± 4.3	−3.5 ± 3.6	8.8 ± 4.2	<0.01	
TT‐TG distance, mm	9.7 ± 3.2	14.4 ± 2.8	−4.8 ± 3.1	<0.01	
Note: All data expressed as mean ± standard deviation.

Abbreviations: ATT, Anterior tibial translation; TT‐TG, tibial tuberosity‐trochlea groove.

John Wiley & Sons, Ltd.

Figure 4 Correlation between the change in medial anterior tibial translation (ΔMedial ATT) and time elapsed since injury (r = −0.04, p = 0.78).

Figure 5 Correlation between the change in lateral anterior tibial translation (Δ Lateral ATT) and time elapsed since injury (r = −0.15, p = 0.25).

Figure 6 Correlation between the change in the tibial tubercle‐trochlear groove (TT‐TG) distance (ΔTT‐TG distance) and time elapsed since injury (r = −0.44, p < 0.01).

Table 3 Post‐operative physical examinations.

Lachman test, negative/trace/positive	62/2/0	
Pivot shift test, negative/glide/clunk/gross	58/6/0/0	
KT‐1000, mm	0.9 ± 0.7	
John Wiley & Sons, Ltd.

Table 4 Pre‐operative and post‐operative KOOS.

	Pre‐operative	Post‐operative	p Value	
Symptom	73.4 ± 21.9	87.7 ± 12.1	<0.01	
Pain	77.5 ± 21.9	94.1 ± 8.0	<0.01	
ADL	79.1 ± 25.9	97.7 ± 3.4	<0.01	
Sports/recreation	49.2 ± 27.9	89.9 ± 14.1	<0.01	
QOL	51.1 ± 26.1	85.2 ± 17.3	<0.01	
Note: All data expressed as mean ± standard deviation.

Abbreviations: ADLs, activities of daily life; KOOS, Knee Injury and Osteoarthritis Outcome Score; QOL, quality of life.

John Wiley & Sons, Ltd.

DISCUSSION

The principal finding of this study is that the tibia underwent internal rotation relative to the femur over time following an ACL injury, despite the absence of a correlation in anterior tibial translation. Nevertheless, pre‐operative medial ATT, lateral ATT and TT‐TG distances were significantly different compared to post‐operative values, with the tibia translating anteriorly and rotating internally relative to the femur after ACL injury.

The ACL, originating from the anteromedial aspect of the tibial plateau to the medial wall of the lateral femoral condyle, plays a crucial role in maintaining a normal tibiofemoral relationship. When the ACL ruptures, it is estimated that the tibia translates anteriorly and rotates internally relative to the femur, although most previous studies have primarily focused on the ATT in the sagittal plane [3, 16]. In studies investigating ATT following ACL injury, the extent of ATT has been shown to be influenced by the chronicity of ACL deficiency, resulting in anterior translation of the tibia relative to the femur [15, 16, 32]. However, no significant correlation was observed between the ATT and the time elapsed since the ACL injury in this study. This may be explained by the fact that this study included patients who underwent MRI within 1 year of ACL injury, whereas ATT has been reported to increase more than 2 years after the ACL injury [18, 32]. To prevent statistical bias towards a specific value, patients with more than 1 year elapsed from injury to undergoing MRI were excluded, as only a few patients visited our hospital after primary ACL injury. Additionally, the exclusion of patients with meniscus injuries, which can influence knee joint laxity, may have impacted our results [6, 21].

Many studies have evaluated the tibiofemoral relationship after ACL injury [4, 8, 15, 32]. The lateral monopodal weight‐bearing radiograph is an easy and reproducible method to measure ATT under loading conditions [4]. Recently, measuring the side‐to‐side difference in ATT under loading conditions in both healthy and ACL‐deficient knees has been implemented as a part of the follow‐up of ACL‐injured patients [15]. Monopodal weight‐bearing radiography offers an easy and objective assessment method. However, several patients could not assume a monomodal position owing to pain and knee instability immediately after ACL injury. Additionally, patients were typically allowed full weight‐bearing 3–4 weeks after ACL reconstruction. Therefore, in our study, MRI and CT were used to evaluate ATT.

Notably, our results represent the first published report identifying an association between the chronicity of ACL deficiency and tibial rotation, as represented by the TT‐TG distance. Several studies have suggested that an increased TT‐TG distance, indicative of external rotation of the tibia, is associated with ACL injury or graft failure after ACL reconstruction [2, 27, 29]. It is conceivable that a larger TT‐TG distance increases the anterior shear force on the tibia, consequently imposing more stress on the ACL [29]. However, in an ACL‐deficient knee, the tibia theoretically experiences internal rotation relative to the femur, resulting in a decrease in the TT‐TG distance [1]. In this study, with respect to the association between the chronicity of ACL deficiency and the TT‐TG distance, the amount of tibial internal rotation was larger in patients with a longer time elapsed from the injury to undergoing MRI, which was theoretically valid.

Regarding clinical outcomes, no significant correlation was found between pre‐operative and post‐operative PROMs and the extent of tibial translation or rotation subsequent to ACL injury. One potential explanation for this lack of correlation is the intentional exclusion of patients with meniscus injuries in our study, as concurrent meniscus injuries might influence clinical outcomes after ACL injury. Furthermore, a previous study highlighted the association between an abnormal pre‐operative tibiofemoral relationship and early graft failure, focusing on the ATT in the sagittal plane [33]. Nevertheless, the rotational aspect of tibial translocation after an ACL injury may also affect early graft failure. Consequently, considering the potential influence of abnormal tibiofemoral relationships caused by meniscus injury and soft tissue decompensation, early ACLR should be considered as a preventive measure.

The strength of this study lies in the exclusion of patients with concomitant meniscus injuries to eliminate the influence of the meniscus on knee joint laxity. This approach sets our study apart from most previous studies, which included patients with concomitant meniscus injuries [6, 21, 24, 32]. It remains uncertain whether an abnormal tibiofemoral relationship resulting from an ACL injury precedes a meniscus injury, or if a concomitant meniscus injury with an ACL injury induces an abnormal tibiofemoral relationship [5, 7, 25]. However, it is widely acknowledged that the meniscus plays a crucial role in the load‐bearing distribution and contributes to joint stabilization [6, 7, 9]. Consequently, patients with meniscus injuries were deliberately excluded from this study to assess the correlation between the time elapsed since the ACL injury and the tibiofemoral relationship.

This study had several limitations. First, MRI and CT were performed only on the injured side. Considering individual differences in anatomy, with variations in the ATT and TT‐TG distance among individuals, a side‐to‐side comparison might have been more informative. However, ethical, social and economic constraints prevented us from conducting MRI and CT of both knees. On the other hand, anatomical ACLR has been proven to restore normal kinematics of the knee joint [16, 22, 23, 31, 32]. Similarly, our post‐operative physical examination and clinical scores showed satisfactory outcomes. In addition, all patients underwent ACLR in the same manner in a single centre. Therefore, the post‐operative measurement values were defined as a baseline for each patient, and the difference between pre‐operative and post‐operative values was used to assess the correlations. Second, CT was taken pre‐operatively, whereas MRI was taken post‐operatively. Lower TT‐TG distances on MRI compared with CT were reported, which depended on the imaging protocol technique within each centre. Specifically, it was also assumed that patient positioning, rather than factors intrinsic to CT or MRI modality, was likely responsible for measurement discrepancies [10]. In this study, CT and MRI were taken with the same protocol in a single centre. Additionally, post‐operative CT scans were obtained with the knee splint immobilized, whereby the knee position was similar to that of a fixed knee coil for MRI; we believe that this lessens the variability depending on patient positioning.

CONCLUSION

The principal finding of this study is that the tibia undergoes internal rotation relative to the femur over time following an ACL injury, despite the absence of a correlation in anterior tibial translation. While the pre‐operative and post‐operative PROMs did not correlate with the extent of anterior tibial translation or internal rotation subsequent to ACL injury, the chronicity of ACL deficiency might lead to a meniscus injury, resulting in worse clinical outcomes. These findings emphasize the importance of early consideration of ACLR to prevent abnormal tibiofemoral relationships, providing valuable insights for clinicians managing patients with ACL injuries.

AUTHOR CONTRIBUTIONS

All authors (1) made substantial contributions to the study concept, data analysis and interpretation; (2) drafted the manuscript or revised it critically for important intellectual content; (3) approved the final version of the manuscript to be published and (4) agreed to be accountable for all aspects of the work.

FUNDING INFORMATION

The authors did not receive support from any organization for the submitted work.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflict of interest.

ETHICS STATEMENT

This study was approved by the Institutional Review Board (approval number: 282‐215). This retrospective chart review involving human participants was conducted in accordance with the ethical standards of the Institutional Committee and the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. All study participants provided informed consent, and the study design was approved by the appropriate ethics review board.

ACKNOWLEDGEMENTS

We wish to thank Editage (www.editage.com) for English language editing.

DATA AVAILABILITY STATEMENT

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data are not available.
==== Refs
REFERENCES

1 Atarod, M. , Frank, C.B. & Shrive, N.G. (2014) Kinematic and kinetic interactions during normal and ACL‐deficient gait: a longitudinal in vivo study. Annals of Biomedical Engineering, 42 , 566–578. Available from: 10.1007/s10439-013-0914-3 24046151
2 Chen, K.J. , Lee, E.J. , Kliethermes, S.A. & Scerpella, T.A. (2023) Association of tibial tubercle‐trochlear groove distance with risk of ACL graft failure. Orthopaedic Journal of Sports Medicine, 11 , 23259671231180860. Available from: 10.1177/23259671231180860 37441506
3 Defrate, L.E. , Papannagari, R. , Gill, T.J. , Moses, J.M. , Pathare, N.P. & Li, G. (2006) The 6 degrees of freedom kinematics of the knee after anterior cruciate ligament deficiency: an in vivo imaging analysis. The American Journal of Sports Medicine, 34 , 1240–1246. Available from: 10.1177/0363546506287299 16636348
4 Dejour, H. & Bonnin, M. (1994) Tibial translation after anterior cruciate ligament rupture. Two radiological tests compared. The Journal of Bone and Joint Surgery. British Volume, 76 , 745–749. Available from: 10.1302/0301-620X.76B5.8083263 8083263
5 Feucht, M.J. , Salzmann, G.M. , Bode, G. , Pestka, J.M. , Kühle, J. , Südkamp, N.P. et al. (2015) Posterior root tears of the lateral meniscus. Knee Surgery, Sports Traumatology, Arthroscopy, 23 , 119–125. Available from: 10.1007/s00167-014-2904-x
6 Franceschini, M. , Reale, D. , Boffa, A. , Andriolo, L. , Tortorella, F. , Grassi, A. et al. (2024) Medial meniscal lesions increase antero‐posterior laxity in knees with anterior cruciate ligament injury. Knee Surgery, Sports Traumatology, Arthroscopy, 32 , 135–142. Available from: 10.1002/ksa.12036
7 Gracia, G. , Cavaignac, M. , Marot, V. , Mouarbes, D. , Laumonerie, P. & Cavaignac, E. (2022) Epidemiology of combined injuries of the secondary stabilizers in acl‐deficient knees: medial meniscal ramp lesion, lateral meniscus root tear, and all tear: a prospective case series of 602 patients with acl tears from the santi study group. The American Journal of Sports Medicine, 50 , 1843–1849. Available from: 10.1177/03635465221092767 35416066
8 Hardy, A. , Klouche, S. , Szarzynski, P. , Charpentier, E. , Beranger, J.S. , Bauer, T. et al. (2019) A threshold value of 3.5 mm of passive anterior tibial subluxation on MRI is highly specific for complete ACL tears. Knee Surgery, Sports Traumatology, Arthroscopy, 27 , 885–892. Available from: 10.1007/s00167-018-5159-0
9 Hatayama, K. , Terauchi, M. , Saito, K. , Takase, R. & Higuchi, H. (2020) Healing status of meniscal ramp lesion affects anterior knee stability after ACL reconstruction. Orthopaedic Journal of Sports Medicine, 8 , 2325967120917674. Available from: 10.1177/2325967120917674 32426412
10 Ho, C.P. , James, E.W. , Surowiec, R.K. , Gatlin, C.C. , Ellman, M.B. , Cram, T.R. et al. (2015) Systematic technique‐dependent differences in CT versus MRI measurement of the tibial tubercle‐trochlear groove distance. The American Journal of Sports Medicine, 43 , 675–682. Available from: 10.1177/0363546514563690 25575535
11 Huntington, L.S. , Webster, K.E. , Devitt, B.M. , Scanlon, J.P. & Feller, J.A. (2020) Factors associated with an increased risk of recurrence after a first‐time patellar dislocation: a systematic review and meta‐analysis. The American Journal of Sports Medicine, 48 , 2552–2562. Available from: 10.1177/0363546519888467 31825650
12 Irrgang, J.J. , Ho, H. , Harner, C.D. & Fu, F.H. (1998) Use of the international knee documentation committee guidelines to assess outcome following anterior cruciate ligament reconstruction. Knee Surgery, Sports Traumatology, Arthroscopy, 6 , 107–114. Available from: 10.1007/s001670050082
13 Kanda, Y. (2013) Investigation of the freely available easy‐to‐use software ‘EZR’ for medical statistics. Bone Marrow Transplantation, 48 , 452–458. Available from: 10.1038/bmt.2012.244 23208313
14 Leite, C.B.G. , Merkely, G. , Farina, E.M. , Smith, R. , Görtz, S. , Hazzard, S. et al. (2023) Effect of tibiofemoral rotation angle on graft failure after anterior cruciate ligament reconstruction. The American Journal of Sports Medicine, 51 , 2291–2299. Available from: 10.1177/03635465231163856 37454271
15 Macchiarola, L. , Jacquet, C. , Dor, J. , Zaffagnini, S. , Mouton, C. & Seil, R. (2022) Side‐to‐side anterior tibial translation on monopodal weightbearing radiographs as a sign of knee decompensation in ACL‐deficient knees. Knee Surgery, Sports Traumatology, Arthroscopy, 30 , 1691–1699. Available from: 10.1007/s00167-021-06719-0
16 Matsuo, T. , Mae, T. , Shino, K. , Kita, K. , Tachibana, Y. , Sugamoto, K. et al. (2014) Tibiofemoral relationship following anatomic triple‐bundle anterior cruciate ligament reconstruction. Knee Surgery, Sports Traumatology, Arthroscopy, 22 , 2128–2135. Available from: 10.1007/s00167-013-2646-1
17 Middleton, K.K. , Gruber, S. & Shubin Stein, B.E. (2019) Why and where to move the tibial tubercle: indications and techniques for tibial tubercle osteotomy. Sports Medicine and Arthroscopy Review, 27 , 154–160. Available from: 10.1097/jsa.0000000000000270 31688534
18 Mishima, S. , Takahashi, S. , Kondo, S. & Ishiguro, N. (2005) Anterior tibial subluxation in anterior cruciate ligament‐deficient knees: quantification using magnetic resonance imaging. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 21 , 1193–1196. Available from: 10.1016/j.arthro.2005.07.008 16226646
19 Mitchell, B.C. , Siow, M.Y. , Bastrom, T. , Bomar, J.D. , Pennock, A.T. , Parvaresh, K. et al. (2021) Coronal lateral collateral ligament sign: a novel magnetic resonance imaging sign for identifying anterior cruciate ligament‐deficient knees in adolescents and summarizing the extent of anterior tibial translation and femorotibial internal rotation. The American Journal of Sports Medicine, 49 , 928–934. Available from: 10.1177/0363546521988938 33617287
20 Muller, B. , Duerr, E.R.H. , van Dijk, C.N. & Fu, F.H. (2016) Anatomic anterior cruciate ligament reconstruction: reducing anterior tibial subluxation. Knee Surgery, Sports Traumatology, Arthroscopy, 24 , 3005–3010. Available from: 10.1007/s00167-015-3612-x
21 Musahl, V. , Citak, M. , O'Loughlin, P.F. , Choi, D. , Bedi, A. & Pearle, A.D. (2010) The effect of medial versus lateral meniscectomy on the stability of the anterior cruciate ligament‐deficient knee. The American Journal of Sports Medicine, 38 , 1591–1597. Available from: 10.1177/0363546510364402 20530720
22 Musahl, V. , Voos, J.E. , O'Loughlin, P.F. , Choi, D. , Stueber, V. , Kendoff, D. et al. (2010) Comparing stability of different single‐ and double‐bundle anterior cruciate ligament reconstruction techniques: a cadaveric study using navigation. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 26 , S41–S48. Available from: 10.1016/j.arthro.2010.01.028 20692120
23 Otsubo, H. , Shino, K. , Nakamura, N. , Nakata, K. , Nakagawa, S. & Koyanagi, M. (2007) Arthroscopic evaluation of ACL grafts reconstructed with the anatomical two‐bundle technique using hamstring tendon autograft. Knee Surgery, Sports Traumatology, Arthroscopy, 15 , 720–728. Available from: 10.1007/s00167-006-0274-8
24 Paul, R.W. , Johnson, E.E. , Hall, A. , Clements, A. , Bishop, M.E. , Ciccotti, M.G. et al. (2022) Comparison of post‐operative outcomes following anterior cruciate ligament reconstruction between patients with vs. without elevated tibial tubercle‐trochlear groove (TT‐TG) distance. Knee Surgery, Sports Traumatology, Arthroscopy, 31 , 2446–2453. Available from: 10.1007/s00167-022-07191-0
25 Praz, C. , Vieira, T.D. , Saithna, A. , Rosentiel, N. , Kandhari, V. , Nogueira, H. et al. (2019) Risk factors for lateral meniscus posterior root tears in the anterior cruciate ligament‐injured knee: an epidemiological analysis of 3956 patients from the santi study group. The American Journal of Sports Medicine, 47 , 598–605. Available from: 10.1177/0363546518818820 30649904
26 Roos, E.M. & Lohmander, L.S. (2003) The Knee Injury and Osteoarthritis Outcome Score (KOOS): from joint injury to osteoarthritis. Health and Quality of Life Outcomes, 1 , 64. Available from: 10.1186/1477-7525-1-64 14613558
27 Saper, M.G. , Popovich, Jr. J.M. , Fajardo, R. , Hess, S. , Pascotto, J.L. & Shingles, M. (2016) The relationship between tibial tubercle‐trochlear groove distance and noncontact anterior cruciate ligament injuries in adolescents and young adults. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 32 , 63–68. Available from: 10.1016/j.arthro.2015.06.036 26343942
28 Schoettle, P.B. , Zanetti, M. , Seifert, B. , Pfirrmann, C.W.A. , Fucentese, S.F. & Romero, J. (2006) The tibial tuberosity‐trochlear groove distance; a comparative study between CT and MRI scanning. The Knee, 13 , 26–31. Available from: 10.1016/j.knee.2005.06.003 16023858
29 Shen, X. , Xiao, J. , Yang, Y. , Liu, T. , Chen, S. , Gao, Z. et al. (2019) Multivariable analysis of anatomic risk factors for anterior cruciate ligament injury in active individuals. Archives of Orthopaedic and Trauma Surgery, 139 , 1277–1285. Available from: 10.1007/s00402-019-03210-x 31190114
30 Shino, K. , Mae, T. & Tachibana, Y. (2015) Anatomic ACL reconstruction: rectangular tunnel/bone‐patellar tendon‐bone or triple‐bundle/semitendinosus tendon grafting. Journal of Orthopaedic Science, 20 , 457–468. Available from: 10.1007/s00776-015-0705-9 25753837
31 Take, Y. , Shino, K. , Mae, T. , Tachibana, Y. , Iuchi, R. , Nakagawa, S. et al. (2018) Early structural results after anatomic triple bundle anterior cruciate ligament reconstruction validated by tunnel location, graft orientation, and static anteroposterior tibia‐femur relationship. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 34 , 2656–2665. Available from: 10.1016/j.arthro.2018.04.015 30078691
32 Tanaka, Y. , Kita, K. , Takao, R. , Amano, H. , Uchida, R. , Shiozaki, Y. et al. (2018) Chronicity of anterior cruciate ligament deficiency, part 1: effects on the tibiofemoral relationship before and immediately after anatomic ACL reconstruction with autologous hamstring grafts. Orthopaedic Journal of Sports Medicine, 6 , 2325967117750813. Available from: 10.1177/2325967117750813 29383322
33 Tanaka, Y. , Kita, K. , Takao, R. , Amano, H. , Uchida, R. , Shiozaki, Y. et al. (2018) Chronicity of anterior cruciate ligament deficiency, part 2: radiographic predictors of early graft failure. Orthopaedic Journal of Sports Medicine, 6 , 232596711775191. Available from: 10.1177/2325967117751915
34 Vahey, T.N. , Hunt, J.E. & Shelbourne, K.D. (1993) Anterior translocation of the tibia at MR imaging: a secondary sign of anterior cruciate ligament tear. Radiology, 187 , 817–819. Available from: 10.1148/radiology.187.3.8497637 8497637
35 Zhang, G.Y. , Ding, H.Y. , Li, E.M. , Zheng, L. , Bai, Z.W. , Shi, H. et al. (2019) Incidence of second‐time lateral patellar dislocation is associated with anatomic factors, age and injury patterns of medial patellofemoral ligament in first‐time lateral patellar dislocation: a prospective magnetic resonance imaging study with 5‐year follow‐up. Knee Surgery, Sports Traumatology, Arthroscopy, 27 , 197–205. Available from: 10.1007/s00167-018-5062-8
