image
Home Journals Acta Academiae Medicinae Sinicae
Acta Academiae Medicinae Sinicae

Abbreviation (ISO4): Acta Academiae Medicinae Sinicae      Editor in chief: Xuetao CAO

About  /  Aim & scope  /  Editorial board  /  Indexed  /  Contact  / 
Online first  /  Current issue  /  All issues  /  Top access  /  RSS

Acta Academiae Medicinae Sinicae >

2024 , Vol. 46 >Issue 6: 814 - 822

DOI: https://doi.org/10.3881/j.issn.1000-503X.16141

Sports Medicine Forums

Effect of Knee Joint Rotational Stability on Sport Performance After Anterior Cruciate Ligament Reconstruction

  • Jingyi SUN 1, 2, 3, 4 ,
  • Feng GAO , 3, 4 ,
  • Yi QIAN 3, 4 ,
  • Yingqi ZHAO 3, 4 ,
  • Chen HE 3, 4 ,
  • Sen GUO 3, 4 ,
  • Jingbin ZHOU , 2
Expand
  • 1Chengdu Sport University,Chengdu 610041,China
  • 2Department of Sport and Rehabilitation Medicine,Beijing Chao-Yang Hospital,Capital Medical University,Beijing 100020,China
  • 3Department of Sports Traumatology,Sports Hospital,National Institute of Sports Medicine, General Administration of Sport of China,Beijing 100061,China
  • 4Key Laboratory of Sports Trauma and Rehabilitation of General Administration of Sport of China,Beijing 100061,China
ZHOU Jingbin Tel:010-89138391,E-mail:;
GAO Feng Tel:010-67116611-301,E-mail:

Received date: 2024-04-23

  Online published: 2025-01-06

Fold

Abstract

Objective To investigate the effects of rotation stability after anterior cruciate ligament reconstruction (ACLR) on subjective outcomes,sport performance,psychological readiness,and return to sport. Methods The patients who underwent ACLR in the Sports Hospital,National Institute of Sports Medicine,General Administration of Sport of China from January 2015 to January 2021 were followed up during the period from November 2022 to December 2023.The patients were grouped according to the results of the pivot shift test (PST) of the affected knee at the last follow-up visit.A total of 66 patients who participated in the follow-up and met the inclusion and exclusion criteria were finally enrolled in this study,including 32 patients showing a negative PST result (stable group) and 34 patients showing a positive PST result (unstable group).The basic information,subjective function score,and return-to-sport performance were compared between the two groups. Results In terms of sport performance,the two groups showed differences in the limb symmetry index in single-leg hops,triple hops,and crossover hops (P=0.028,P=0.024,and P=0.044,respectively).The anterior cruciate ligament-return to sport after injury scale score was higher in the stable group than in the unstable group [(70.44±22.82) scores vs. (53.44±21.74) scores,P=0.003].The mean of KT-2000 test results in the stable group was lower than that in the unstable group [(0.53±1.02) mm vs. (2.06±2.31) mm,P=0.001].The Lysholm score,international knee documentation committee score,knee injury and osteoarthritis outcome score,Tegner score,and Marx score did not have significance between the two groups (all P>0.05).The return-to-sport rate was 43.8% (including 14.3% reaching safe return criteria,which accounted for 6.3% in all the patients) in the stable group and 35.3% (including 8.3% reaching safe return criteria,which accounted for 2.9% in all the patients) in the unstable group.There was no difference in the 60°/s isokinetic muscle strength,maximal muscle strength ratio of the affected extensor-flexor muscles,or Y-balance test result between the two groups (all P>0.05). Conclusions Knee joint rotational instability after ACLR results in poor performance in single-leg hops,triple hops,and crossover hops,low psychological readiness,and anterior-posterior knee laxity.In short- to medium-term follow-up for ACLR,the return-to-sport rate remained low regardless of knee joint rotational stability,with the majority of patients failing to meet safe return criteria.

Key words： rotational instability; anterior cruciate ligament reconstruction; sport performance; return to sport

Cite this article

Jingyi SUN , Feng GAO , Yi QIAN , Yingqi ZHAO , Chen HE , Sen GUO , Jingbin ZHOU . Effect of Knee Joint Rotational Stability on Sport Performance After Anterior Cruciate Ligament Reconstruction[J]. Acta Academiae Medicinae Sinicae, 2024 , 46(6) : 814 -822 . DOI: 10.3881/j.issn.1000-503X.16141

Anterior cruciate ligament (ACL) injury is one of the common sports injuries of the knee, with an incidence rate of about 0.04%, and it is on the rise globally[1]. The ACL is the main anatomical structure in the knee that restricts anterior tibial translation and internal tibial rotation[2]; when it is injured, it can cause anteroposterior and rotational instability of the knee, leading to abnormal movement patterns[3]. ACL reconstruction (ACLR) is the primary treatment for restoring knee stability and function after ACL injury, helping patients return to sports, but some patients still experience mild rotational instability post-surgery. Whether this residual knee instability after ACLR is associated with subjective functional scores and athletic performance remains unclear and is controversial in clinical significance[4-5]. Some studies suggest that there is no correlation between knee stability and postoperative subjective scores[6-7], or with athletic performance[8-9], while other studies propose that mild knee instability can increase the risk of revision and significantly affect subjective functional outcomes[4,10]. Therefore, how to evaluate the residual knee rotational instability after ACLR has become a focal point of academic attention in recent years.
The rotational stability of the knee joint is typically assessed through physical examination. Galway et al.[11] first described the pivot shift test, a phenomenon of rotational instability observed in knees with ACL injuries, which is specific and now widely used for post-ACLR evaluation. Additionally, patient-reported outcome measures such as the Lysholm score, International Knee Documentation Committee (IKDC) score, Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner score, and Marx score are frequently used to evaluate the effectiveness of ACLR. Among these, the Tegner and Marx scores reflect the pre-injury activity level and postoperative recovery, allowing for an assessment of whether patients have returned to their pre-injury activity levels by comparing pre- and post-operative scores[12-13]. Webster et al.[14] developed the Return to Sport after Injury (RSI) score for ACL injuries, which is considered a reliable indicator of postoperative psychological status[15-16]. According to the latest 2020 Panther guidelines, athletic performance is also an aspect of postoperative functional assessment, including lower limb strength, jump tests, and balance tests[17]. Therefore, this study aims to investigate, through short- to medium-term follow-up, whether post-ACLR rotational stability affects subjective outcomes and athletic performance, and to compare the differences in subjective scores and athletic performance between patients with positive and negative pivot shift tests, providing references for clinical treatment.

1 Objects and Methods

1.1 Object

This study conducted a concentrated follow-up from November 2022 to December 2023 on patients who underwent ACLR surgery at the National Sports General Administration's Sports Hospital Institute of Sports Medicine between November 2015 and November 2021. Inclusion criteria: (1) aged 16-50 years; (2) clinically diagnosed with complete ACL rupture; (3) first-time undergoing ACLR surgery; (4) epiphyseal closure; (5) ≥24 months post-ACLR surgery; (6) able to be contacted and willing to participate in the follow-up. A total of 106 patients were included, and patients were excluded based on the following: (1) those who underwent revision ACL surgery between the time of surgery and follow-up (n=11); (2) concurrent posterior cruciate ligament injury (n=3); (3) other surgeries affecting knee function on the surgical side (n=2); (4) surgeries affecting knee function on the contralateral knee (n=6); (5) grafts not autologous hamstring tendon (n=5); (6) non-anatomical single-bundle reconstruction technique (n=3); (7) generalized ligamentous laxity (n=3); (8) severe genu varum or valgus (n=0); (9) unable to complete all required examinations or assessments for the follow-up (n=7). Ultimately, 66 patients who met the inclusion and exclusion criteria participated in the follow-up. This study was approved by the Ethics Committee of the National Sports General Administration's Institute of Sports Medicine (Ethics Review No.: 202210). All participants signed informed consent forms.

1.2 Exposure Group

All surgeries were performed by the same senior clinical physician in sports medicine. According to the axial shift test grading method proposed by Jakob et al[18], at follow-up, if no reduction or knee joint dislocation occurred during knee flexion, it was classified as grade 0 of the axial shift test; if sliding reduction occurred during knee flexion, it was classified as grade 1; if tibial jump reduction occurred during knee flexion, it was classified as grade 2; and if transient locking occurred during knee flexion, sometimes requiring manual assistance for tibial reduction, it was classified as grade 3. To ensure the accuracy of the axial shift test results, all axial shift tests were independently conducted and recorded by two senior surgeons specializing in sports medicine. The recorded data were statistically integrated. Patients with consistent judgments of grade 1 or 2 were included in the unstable group, while those with grade 0 were included in the stable group. In cases of inconsistent judgments, the axial shift test under anesthesia was performed. Ultimately, there were 2 patients with different axial shift test results, so they were retested under anesthesia, both resulting in grade 2. A total of 32 cases showed grade 0 on the axial shift test, classified as the stable group; 29 cases showed grade 1, and 5 cases showed grade 2, collectively classified as the unstable group.

1.3 Evaluation Metrics

Record the basic information of the enrolled patients, including gender, age at surgery, body mass index (BMI), affected side, time from injury to surgery, meniscus injury status, and follow-up duration. At postoperative follow-up, the anterior-posterior stability of the knee joint was evaluated using the KT-2000, and subjective scores included Lysholm, IKDC, KOOS, Tegner, ACL-RSI psychological score, and Marx score. Athletic performance assessments included isokinetic muscle strength of the affected knee at 60°/s, maximum muscle strength of the extensors and flexors on the affected side, jump tests, and Y-balance test (YBT). For ease of calculation, the results of the KT-2000 test were expressed as the difference between the affected and unaffected sides, while the results of isokinetic muscle strength, jump tests, and YBT were expressed using the limb symmetry index (LSI).
Meredith et al.[17]defined return to sport as returning to the type, level, intensity, and frequency of sport prior to injury. Therefore, this study determined whether a return to sport was achieved based on whether the postoperative Tegner and Marx scores reached pre-injury levels. Some studies have shown that when the isokinetic maximum flexor strength, extensor strength at 60°/s, single-leg hop, triple hop, crossover hop, and 6 m timed hop test LSI are all >90%, the re-injury rate of the knee joint during return to sport is reduced by 84%[19]. It is recommended that safe return to sport criteria should include postoperative time, subjective scores, objective assessment of knee function, and psychological readiness assessment. Thus, this study, in conjunction with relevant research, established the following safe return to sport criteria[20⇓⇓-23]: (1) Postoperative time ≥ 9 months; (2) Lower limb maximum muscle strength LSI ≥ 85%; (3) ACL-RSI > 65; (4) Hop test LSI ≥ 85%; (5) YBT LSI ≥ 85%; (6) Both Tegner and Marx scores restored to pre-injury levels. Any individual not meeting any one of the above criteria is considered not to have safely returned to sport.

1.4 Follow-up and Outcome Information Collection

1.4.1 Isokinetic Muscle Strength Testing

Isokinetic muscle strength testing uses the American Biodex system 4 isokinetic muscle strength testing system to test the peak torque of patients' knee extensors and flexors, mainly used to evaluate the maximum muscle strength of the knee flexion and extension muscle groups under low-speed dynamic conditions. After the subjects have fully warmed up, they undergo adaptive training for isokinetic muscle strength testing of the knee joint under the guidance of professional testers, and formal testing begins after full adaptation. The subjects sit on the test chair, with the trunk and the tested leg secured by a safety belt, and the direction of the knee joint being tested is kept consistent with the direction of the power arm. According to the subjects, the range of motion of the knee joint is set, basic information is edited, and the angular velocity of knee flexion and extension movements is adjusted to 60°/s for testing, with the healthy side tested before the affected side.

1.4.2 Jump Test

Three functional tests were selected: single-leg hop, single-leg triple hop, and single-leg cross triple hop[24]. The specific test routes are shown in Figure 1. Before each test, the tester explains and demonstrates to the participant, allowing them to become familiar with the testing process and movements. Participants practice with each leg before the formal test to get accustomed to the test movements; a test is considered successful if the participant can maintain their landing position for at least 2 seconds. Each test is performed three times, and the longest distance (accurate to 1 cm) is recorded. If the third attempt is the farthest, a fourth attempt is made; if the fourth attempt is the farthest, it is included in the data analysis. A test is deemed unsuccessful under the following circumstances: when the contralateral lower limb or upper limb of the participant touches the ground, they lose balance, or there is an additional hop during the initial landing. There is a 30-second interval between the same tests and a 2-minute interval between different test items.
Figure 1 Schematic Diagram of Jump Test Movements

A. Single-leg single-stage jump; B. Single-leg triple jump; C. Single-leg cross jump

1.4.3 YBT

Place the YBT kit (Functional Movement Screen System from the USA) on a flat testing surface. The angle between the anterior tube and both the posteromedial and posterolateral tubes of the YBT kit is 135°, and the angle between the posteromedial and posterolateral tubes is 90°. The central area among the three directions serves as the standing zone for the supporting leg. The participant stands barefoot on a force platform marked with the YBT kit, with the supporting leg's big toe behind the central horizontal line, aligned straight ahead, and hands on the waist. The other leg is extended sequentially in the anterior, posterolateral, and posteromedial directions, recording the distance extended, expressed in raw values (cm). After extending three times in each direction, move to the next direction.
Before the formal test, appropriate warm-up activities are conducted. The subjects practice three times in each direction to familiarize themselves with the test movements. After a 5-minute rest, the formal test is carried out. If the subject fails to extend successfully after three attempts, the distance for that direction is recorded as 0 cm. During the extension, the subject must not use the barrier as a support point for the forward leg. The following situations are considered failures and will not be included in the data analysis: losing balance while standing on one leg, significant movement of the standing foot, the extending foot touching the ground for support, and the extending leg not returning to the initial position.

1.5 Statistical Analysis

Statistical analysis was performed using SPSS 26.0. Continuous variables were expressed as mean ± standard deviation, while categorical or ordinal variables were presented as counts and percentages. Independent sample t tests were used to compare the surgical age, BMI, time from injury to surgery, KT-2000 difference between the affected and unaffected sides, Lysholm, IKDC, KOOS, ACL-RSI, Tegner, Marx, isokinetic muscle strength LSI at 60°/s, maximum flexor-extensor muscle strength ratio of the affected side, and jump test LSI among groups. The chi-square test for contingency tables was applied to compare gender, affected side, and meniscus injury status among groups. Paired t tests were conducted to compare the pre-injury and post-surgery Tegner and Marx scores of the same patients. A P value <0.05 was considered statistically significant.

2 Results

2.1 Baseline Data

A total of 66 patients were included, with an average enrollment age of (31.12±8.32) years (14 to 48 years), and an average follow-up time of (4.26±2.09) years (2 to 9 years). There were 47 male patients (71.21%) and 19 female patients (28.79%). There were no statistically significant differences between the two groups in terms of gender, surgical age, body mass index, time from injury to surgery, affected side, and meniscus injury status (P all >0.05)(Table 1).
Table 1 The basic information of the two groups of patients
grouping gender [n(%)] ($\bar{x}\pm s$, years)
($\bar{x}\pm s$,岁)		 body mass index
($\bar{x}\pm s$,kg/m2)		 Time from injury to surgery
($\bar{x}\pm s$,d)		 Affected side [n(%)]
male female left right
stable group (n=32) 25(78.1) 7(21.9) 30.63±8.72 24.64±3.34 130.69±291.55 22(68.8) 10(31.2)
unstable group (n=34) 22(64.7) 12(35.3) 31.59±8.02 24.34±2.88 180.35±377.96 20(58.8) 14(41.2)
t/x2 1.448 -0.467 0.387 -0.595 0.702
P 0.229 0.642 0.700 0.993 0.402
grouping Meniscus injury [n(%)] Pre-injury Tegner ($\bar{x} \pm s$, years) Pre-injury Marx ($\bar{x} \pm s$, years)
None medial lateral bilateral
stable group (n=32) 10(31.3) 13(40.6) 6(18.8) 3(9.4) 6.59±1.43 12.69±4.31
unstable group (n=34) 13(38.2) 13(38.2) 4(11.8) 4(11.8) 6.59±0.70 10.82±3.45
t/χ2 0.874 0.020 1.946
P 0.832 0.984 0.056

2.2 Anteroposterior Stability of the Knee at Follow-up

The results of the KT-2000 arthrometer showed that the difference in KT-2000 test values between the healthy side and the affected side in the stable group [(0.53±1.02) mm] was significantly smaller than that in the unstable group [(2.06±2.31) mm] (P=0.001).

2.3 Subjective Scale Scores at Follow-up

The differences in Lysholm, IKDC, and KOOS scores between the two groups of patients were not statistically significant (P all >0.05). However, the ACL-RSI score of the stable group was significantly higher than that of the unstable group (P=0.003) (Table 2). In addition, there were no statistically significant differences in Tegner and Marx scores between the two groups postoperatively (P=0.067, P=0.126), but compared to pre-injury, the Tegner and Marx scores of both groups of patients after ACLR significantly decreased (P all <0.001) (Table 3, 4).
Table 2 The subjective scale scores of the two groups of patients during follow-up ($\bar{x}\pm s$, points)
grouping Lysholm International Knee Documentation Committee Evaluation Form Knee Injury and Osteoarthritis Outcome Score Anterior Cruciate Ligament - Return to Sport after Injury Psychological Score
stable group (n=32) 81.06±18.18 81.18±13.28 82.87±11.18 70.44±22.82
unstable group (n=34) 81.82±15.17 80.98±11.43 79.62±12.95 53.44±21.74
t -0.185 0.066 1.089 3.098
P 0.854 0.947 0.280 0.003
Table 3 The pre-injury and postoperative Tegner scores of the two groups of patients ($\bar{x}\pm s$, points)
grouping Pre-injury postoperative t/x2 P
stable group (n=32) 6.59±1.43 6.03±1.56 3.302 <0.001
unstable group (n=34) 6.59±0.70 5.24±1.89 3.671 <0.001
t 0.020 1.872
P 0.984 0.067
Table 4 The pre-injury and postoperative Marx scores of the two groups of patients ($\bar{x}\pm s$, points)
grouping Pre-injury postoperative t P
stable group (n=32) 12.69±4.31 8.59±5.77 4.627 <0.001
unstable group (n=34) 10.82±3.45 6.59±4.63 4.813 <0.001
t 1.946 1.563
P 0.056 0.126

2.4 Exercise Performance at Follow-up

The return-to-sport rate for the stable group was 43.8%, with 14.3% of patients meeting the safety return criteria, accounting for 6.3% of all patients; the return-to-sport rate for the unstable group was 35.3%, with 8.3% of patients meeting the safety return criteria, accounting for 2.9% of all patients. The difference in the proportion of patients meeting the safety return criteria between the two groups was not statistically significant (P=0.416). The LSI for single-leg hop (P=0.028), triple hop (P=0.024), and crossover hop (P=0.044) in the stable group were significantly higher than those in the unstable group. There were no statistically significant differences in other sports performance indicators between the two groups (P all >0.05) (Table 5).
Table 5 The results of the exercise performance tests for the two groups of patients during follow-up ($\bar{x}\pm s$)
grouping 60°/s isokinetic muscle strength test (%) Ratio of maximum muscle strength of the flexor and extensor on the affected side
Maximum extensor muscle strength LSI Maximum flexor muscle strength LSI
stable group (n=32) 77.89±30.14 90.18±24.75 0.61±0.26
unstable group (n=34) 85.67±41.55 93.83±30.93 0.56±0.26
t -0.867 -0.528 0.824
P 0.389 0.599 0.413
grouping Jump test LSI (%) Y Balance Test LSI (%)
hop on one foot triple jump cross jump Y-forward Y-posterolateral Y-posteromedial
stable group (n=32) 81.79±29.34 86.03±27.53 85.79±26.54 93.60± 9.95 98.28± 8.49 96.35±10.15
unstable group (n=34) 63.36±36.58 67.86±35.42 69.58±36.56 89.35±24.82 95.23±25.18 90.95±24.90
t 2.249 2.316 2.050 0.902 0.650 1.141
P 0.028 0.024 0.044 0.370 0.518 0.258

Note: LSI: limb symmetry index

3 Discussion

This study shows that patients with good knee rotational stability have significantly higher LSI in single-leg hop, triple hop, and crossover hop during sports performance compared to unstable patients. In the ACL-RSI psychological assessment, the stable group also scored significantly higher than the unstable group, indicating that knee stability after ACLR may play a crucial role in medium- to short-term knee function and return to sports recovery.
The jump test is generally used to assess the neuromuscular control of the knee, and after ACLR, the neuromuscular control of the knee during jump landing is very poor[25]. Müller et al.[26] showed that among three types of jump tests, the single-leg hop is one of the most sensitive tests for returning to recreational sports activities 6 months after ACLR. The results of triple-hop and cross-over hop tests are closely related to the recovery of quadriceps and hamstring muscle strength in the lower limbs, but not related to the rotational stability of the knee[27]. In this study, there was no statistically significant difference in the isokinetic muscle strength at 60°/s between the two groups, and the ratio of maximum muscle strength of the extensor and flexor on the affected side was similar. However, the LSI of the three jump tests in the knee joint stability group was significantly higher than that in the instability group, indicating that the stability of the knee during dynamic activities affects neuromuscular control function. This functional deficiency may lead to excessive load on structures such as ligaments and joint capsules, ultimately increasing the risk of re-injury of the ACL[28]. In other words, these jump tests can, to some extent, predict the postoperative stability of the knee, objectively evaluating the effectiveness of ACLR and the safety of returning to sports. Jonsson et al.[29] found no statistically significant difference in the single-leg hop test results between patients with a negative pivot shift test and those with a positive pivot shift test during a 5-9 year follow-up. Sundemo et al.[30] found a trend of better single-leg hop test results in patients with a negative pivot shift test compared to those with a positive pivot shift test 2 years after ACLR, although the difference was not statistically significant. However, a statistically significant difference was observed 16 years post-surgery. This might be due to compensation through increased muscle strength in the early postoperative period, maintaining the rotational stability of the knee during movement[31]. However, this stability is temporary, and extensive exercise or long-term wear and tear can cause abnormal stress changes in the joint structures, potentially leading to gradual degenerative changes in the joint and a decline in athletic performance over time[30].
The ACL-RSI scale has recently been considered a reliable and effective tool for evaluating return to sports[32]. In this study, the ACL-RSI score of the stable group was significantly higher than that of the unstable group. According to the RSI score standard for returning to sports in Albano et al.'s[21] research, the average score of the stable group met the criteria for returning to sports, while the unstable group did not, indicating that post-ACLR knee rotational stability may affect the psychological state when returning to sports. Some studies have shown that the degree of knee laxity can be predicted by the ACL-RSI score, with more lax knees having lower psychological scores[33]. McPherson et al.[34] speculated that this is due to the fear of reinjury caused by the inherent instability of the knee, thereby lowering the psychological score. However, a univariate correlation analysis showed no correlation between the degree of anterior-posterior knee laxity and the ACL-RSI score[14]. This may be because the patients included in the study were all athletes or sports enthusiasts with strong muscle foundations, whose muscle strength and neuromuscular feedback partially compensated for the mechanical stability of the lax knee, thus producing this discrepancy; the results of this study may not apply to the general population. So far, monitoring psychological status is not yet an important component of current rehabilitation programs. The results of this study provide a reference for the importance of psychological assessment, showing that the ACL-RSI score can reflect the postoperative knee stability status in terms of returning to sports, further indicating the necessity of addressing adverse psychological reactions during rehabilitation. It is suggested that the ACL-RSI could be incorporated into routine clinical evaluations, and for patients with low psychological scores, additional psychological intervention treatments should be added on top of conventional rehabilitation. Since the ACL-RSI scoring scale mainly includes three parts: subjective emotions, confidence in performing sports, and risk assessment, how to conduct targeted psychological treatment—whether through continuous verbal encouragement, self-suggestion, or medical psychological counseling to increase confidence and reduce anxiety and fear, or by improving knee stability and athletic ability through strengthening lower limb muscles, thereby enhancing psychological readiness—is a direction for future clinical research and work.
In terms of anterior-posterior stability of the knee joint, this study showed that the test results from the KT-2000 arthrometer in the stable group were significantly less than those in the unstable group. According to the definition by IKDC, a measurement difference <3 mm between the affected and healthy knee joints is considered normal[35], therefore, the results of both groups in this study were within an acceptable range. The essence of the pivot shift test is to check for ligament laxity in the knee joint. Jakob et al.[18] demonstrated that during the pivot shift test, the tibia not only produces rotational subluxation relative to the femur but also has varying degrees of anterior translation on the medial and lateral platforms. The results of the pivot shift test include the distance of anterior displacement, which reflects the kinematics of the knee joint more comprehensively than the KT-2000 arthrometer[36].
The ultimate goal of testing for athletic performance is to assess the safety of patients returning to sports. Grindem et al.[19] found that even after patients return to sports following ACLR, they still have a high risk of secondary injury; however, when certain criteria are met, the rate of knee re-injury upon returning to sports decreases by 84%. Therefore, this study, in conjunction with the Panther guidelines[17], added the Marx score to the existing standards, which can more specifically evaluate the athletic capability of the knee, thereby setting a standard for safe return to sports, which may be more scientific and objective. The results of this study showed that the proportion of patients in the knee stability group who met the safe return-to-sports criteria was twice that of the instability group, although the difference between the two groups was not statistically significant. However, the authors believe that the role of knee rotational stability in safely returning to sports cannot be ignored. Zhou et al.[28] found that patients who did not meet the safe return-to-sports criteria postoperatively had a greater lateral tibial translation distance and a more pronounced external tibial rotation angle, also indicating from another perspective the importance of the recovery of knee rotational stability after ACLR for a safe return to sports.
This study shows that the proportion of patients who meet the safety return-to-sport criteria is very low, regardless of knee stability. Sheean et al.[13] found that even if postoperative patients can return to sports, they are more likely to suffer re-injury due to functional deficits or inadequate recovery. This study also indicates a significant decrease in the Marx scores of postoperative patients, suggesting that reconstructive surgery affects their lifestyle and exercise habits, with most patients reducing their exercise frequency. Liu et al.[37] reported that the return-to-sport rate for professional basketball players after ACLR ranges from 74% to 91%, significantly higher than the return-to-sport rate in this study. This difference is mainly due to the different study populations; the patients in this study were from the general population. Most patients reduce or even stop rehabilitation once their knee function gradually meets the needs of daily activities, at which point the knee function has not yet recovered to a level safe for sports participation. The inadequacy of rehabilitation may be an important reason affecting the return-to-sport rate and its safety. Lindanger et al.[38] proposed that postoperative rehabilitation is one of the key factors influencing the return to sports, and exercising under the supervision of a professional rehabilitation therapist is more effective than without such supervision[39]. However, the goal for professional athletes post-surgery is to return to competition as soon as possible and regain their previous competitive level. They typically have comprehensive medical support, including continuous and personalized rehabilitation and specialized physical training, which are reasons why their return-to-sport rates are higher than those of the general population in this study. Nevertheless, there are few reports on whether these returning athletes meet the safety criteria for return to sport, and further investigation is needed. The results of this study show a low proportion of patients safely returning to sports, indicating that clinicians need to strengthen patient education, guide them to set correct rehabilitation goals, fully inform them of the importance of postoperative rehabilitation for functional recovery and return to sport, and encourage them to aim for the safety criteria for return to sport and persist in rehabilitation training.
This study has certain advantages and limitations. Currently, many reports on the stability of the knee after ACLR are limited to short-term follow-ups, mainly based on the degree of anterior-posterior laxity. In contrast, this study explores the impact of rotational stability of the knee on return to sports by combining pivot shift test results, with a longer follow-up period (2-9 years). Furthermore, this study concretizes the return to sports, not only using questionnaires but also considering multiple aspects of objective athletic performance, including lower limb strength, jump tests, and balance ability tests. The limitations are as follows: (1) The pivot shift test of the knee is a subjective assessment, which may have biases, or the results may be inaccurate due to muscle tension in patients during the test. However, in this study, two sports medicine experts conducted the tests separately, and when their results differed, the test was performed under anesthesia to minimize such errors as much as possible; (2) This study only included 66 cases, so the sample size remains small; (3) Due to the small sample size, the study did not conduct subgroup analysis by grading positive pivot shift test patients, therefore, it is unclear whether there are differences between mild rotational instability and moderate to high degrees of rotational instability; (4) This study did not record factors such as the duration of postoperative rehabilitation and the time from surgery to return to sports, all of which could potentially influence the patient's ability to safely meet the criteria for returning to sports.
In summary, rotational instability of the knee after ACLR results in poorer performance in single-leg hop, triple hop, and crossover hop. Patients with stable knees have higher ACL-RSI scores than those with unstable knees, and the stable group meets the criteria for safe return to sports, while the unstable group does not. Furthermore, rotational stability of the knee significantly affects the results of the KT-2000 test, with rotationally unstable knees showing more anterior-posterior laxity. However, rotational stability of the knee has no impact on Lysholm, IKDC, KOOS, Tegner, Marx scores, 60°/s isokinetic muscle strength, maximum muscle strength of the flexors and extensors of the affected side, and YBT performance. In short-term follow-up after ACLR, regardless of the rotational stability of the knee, the rate of return to sports is low, with most people failing to meet the criteria for a safe return to sports.
Conflict of Interest All authors declare no conflict of interest
Author Contribution Statement Sun Jingyi: participated in the selection of research topics, experimental design, implementation, data collection and statistics, and writing of the paper; Qian Yi, Zhao Yingqi: participated in the selection of research topics, experimental design, and data collection; He Chen, Guo Sen: participated in the selection of research topics and experimental design; Gao Feng, Zhou Jingbin: participated in the selection of research topics, experimental design, guidance of the research, and revision of the paper

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]
Noyes FR, Huser LE, Levy MS. The effect of an ACL reconstruction in controlling rotational knee stability in knees with intact and physiologic laxity of secondary restraints as defined by tibiofemoral compartment translations and graft forces[J]. J Bone Joint Surg Am, 2018, 100(7):586-597.DOI:10.2106/JBJS.16.01412.

[2]
贺忱, 高奉, 钱驿, 等. 前交叉韧带重建术后残留轻度旋转不稳的风险因素分析[J]. 实用骨科杂志, 2021, 27(1):21-26.DOI:10.13795/j.cnki.sgkz.2021.01.005.

[3]
Snoeker B, Turkiewicz A, Magnusson K, et al. Risk of knee osteoarthritis after different types of knee injuries in young adults:a population-based cohort study[J]. Br J Sports Med, 2020, 54(12):725-730.DOI:10.1136/bjsports-2019-100959.

[4]
Lindanger L, Strand T, Molster AO, et al. Effect of early residual laxity after anterior cruciate ligament reconstruction on long-term laxity,graft failure,return to sports,and subjective outcome at 25 years[J]. Am J Sports Med, 2021, 49(5):1227-1235.DOI:10.1177/0363546521990801.

[5]
Zhang X, Qian Y, Gao F, et al. High anteromedial insertion reduced anteroposterior and rotational knee laxity on mid-term follow-up after anatomic anterior cruciate ligament reconstruction[J]. PeerJ, 2023, 11:e15898.DOI:10.7717/peerj.15898.

[6]
Magnussen RA, Reinke EK, Huston LJ, et al. Neither residual anterior knee laxity up to 6 mm nor a pivot glide predict patient-reported outcome scores or subsequent knee surgery between 2 and 6 years after ACL reconstruction[J]. Am J Sports Med, 2021, 49(10):2631-2637.DOI:10.1177/03635465211025003.

[7]
贺忱, 赵志宏, 高奉, 等. 前交叉韧带重建术后轻度旋转不稳定对临床疗效的影响[J]. 实用骨科杂志, 2020, 26(9):787-791.DOI:10.13795/j.cnki.sgkz.2020.09.005.

[8]
Kim JS, Hwang UJ, Choi MY, et al. Correlation between Y-balance test and balance,functional performance,and outcome measures in patients following ACL reconstruction[J]. Int J Sports Phys Ther, 2022, 17(2):193-200.DOI:10.26603/001c.31873.

[9]
Meyer C, Gette P, Mouton C, et al. Side-to-side asymmetries in landing mechanics from a drop vertical jump test are not related to asymmetries in knee joint laxity following anterior cruciate ligament reconstruction[J]. Knee Surg Sports Traumatol Arthrosc, 2018, 26(2):381-390.DOI:10.1007/s00167-017-4651-2.

[10]
Michel E, Jordan E, Canovas F, et al. Influence of residual anterior laxity on functional outcomes after anterior cruciate ligament reconstruction[J]. Orthop Traumatol Surg Res, 2022, 108(3):103264.DOI:10.1016/j.otsr.2022.103264.

[11]
Galway HR, MacIntosh DL. The lateral pivot shift:a symptom and sign of anterior cruciate ligament insufficiency[J]. Clin Orthop Relat Res, 1980, 147:45-50.

[12]
Sonnery-Cottet B, Saithna A, Cavalier M, et al. Anterolateral ligament reconstruction is associated with significantly reduced ACL graft rupture rates at a minimum follow-up of 2 years:a prospective comparative study of 502 patients from the SANTI study group[J]. Am J Sports Med, 2017, 45(7):1547-1557.DOI:10.1177/0363546516686057.

[13]
Sheean AJ, Jin Y, Huston LJ, et al. Predictors of return to activity at 2 years after anterior cruciate ligament reconstruction among patients with high preinjury Marx activity scores:a MOON prospective cohort study[J]. Am J Sports Med, 2023, 51(9):2313-2323.DOI:10.1177/03635465231172769.

[14]
Webster KE, Nagelli CV, Hewett TE, et al. Factors associated with psychological readiness to return to sport after anterior cruciate ligament reconstruction surgery[J]. Am J Sports Med, 2018, 46(7):1545-1550.DOI:10.1177/0363546518773757.

[15]
O’Connor RF, King E, Richter C, et al. No relationship between strength and power scores and anterior cruciate ligament return to sport after injury scale 9 months after anterior cruciate ligament reconstruction[J]. Am J Sports Med, 2020, 48(1):78-84.DOI:10.1177/0363546519887952.

[16]
钱驿, 周敬滨, 贺忱, 等. 前交叉韧带重建术后重返运动相关因素的研究进展[J]. 体育科研, 2020, 41(3):7-13.DOI:10.12064/ssr.20200302.

[17]
Meredith SJ, Rauer T, Chmielewski TL, et al. Return to sport after anterior cruciate ligament injury:panther symposium ACL injury return to sport consensus group[J]. Knee Surg Sports Traumatol Arthrosc, 2020, 28(8):2403-2414.DOI:10.1007/s00167-020-06009-1.

[18]
Jakob RP, Staubli HU, Deland JT. Grading the pivot shift objective tests with implications for treatment[J]. J Bone Joint Surg Br, 1987, 69(2):294-299.DOI:10.1302/0301-620X.69B2.3818763.

[19]
Grindem H, Snyder-Mackler L, Moksnes H, et al. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction:the Delaware-Oslo ACL cohort study[J]. Br J Sports Med, 2016, 50(13):804-808.DOI:10.1136/bjsports-2016-096031.

[20]
Gokeler A, Welling W, Zaffagnini S, et al. Development of a test battery to enhance safe return to sports after anterior cruciate ligament reconstruction[J]. Knee Surg Sports Traumatol Arthrosc, 2017, 25(1):192-199.DOI:10.1007/s00167-016-4246-3.

[21]
Albano TR, Rodrigues C, Melo A, et al. Clinical decision algorithm associated with return to sport after anterior cruciate ligament reconstruction[J]. J Athl Train, 2020, 55(7):691-698.DOI:10.4085/1062-6050-82-19.

[22]
Faltstrom A, Hagglund M, Kvist J. Patient-reported knee function,quality of life,and activity level after bilateral anterior cruciate ligament injuries[J]. Am J Sports Med, 2013, 41(12):2805-2813.DOI:10.1177/0363546513502309.

[23]
Burgi CR, Peters S, Ardern CL, et al. Which criteria are used to clear patients to return to sport after primary ACL reconstruction? A scoping review[J]. Br J Sports Med, 2019, 53(18):1154-1161.DOI:10.1136/bjsports-2018-099982.

[24]
Paterno MV, Huang B, Thomas S, et al. Clinical factors that predict a second ACL injury after ACL reconstruction and return to sport:preliminary development of a clinical decision algorithm[J]. Orthop J Sports Med, 2017, 5(12):2325967117745279.DOI:10.1177/2325967117745279.

[25]
Hewett TE, Myer GD, Ford KR, et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes:a prospective study[J]. Am J Sports Med, 2005, 33(4):492-501.DOI:10.1177/0363546504269591.

[26]
Müller U, Krüger-Franke M, Schmidt M, et al. Predictive parameters for return to pre-injury level of sport 6 months following anterior cruciate ligament reconstruction surgery[J]. Knee Surg Sports Traumatol Arthrosc, 2015, 23(12):3623-3631.DOI:10.1007/s00167-014-3261-5.

[27]
Al-Gburi M, Kristiansen JB, Christensen KB, et al. Functional performance tests,clinical measurements,and patient-reported outcome measures do not correlate as outcomes 1 year after anterior cruciate ligament reconstruction[J]. Knee Surg Sports Traumatol Arthrosc, 2023, 31(12):5905-5912.DOI:10.1007/s00167-023-07648-w.

[28]
Zhou T, Xu Y, Zhou L, et al. Multi-planar instability,laxity and reduced knee flexion during the support phase of walking are determinants of return to sports[J]. Front Bioeng Biotechnol, 2022, 10(3):1047135.DOI:10.3389/fbioe.2022.974724.

[29]
Jonsson H, Riklund-Ahlstrom K, Lind J. Positive pivot shift after ACL reconstruction predicts later osteoarthrosis:63 patients followed 5-9 years after surgery[J]. Acta Orthop Scand, 2004, 75(5):594-599.DOI:10.1080/00016470410001484.

[30]
Sundemo D, Sernert N, Kartus J, et al. Increased postoperative manual knee laxity at 2 years results in inferior long-term subjective outcome after anterior cruciate ligament reconstruction[J]. Am J Sports Med, 2018, 46(11):2632-2645.DOI:10.1177/0363546518786476.

[31]
Aizawa J, Hirohata K, Ohji S, et al. Cross-sectional study on relationships between physical function and psychological readiness to return to sport after anterior cruciate ligament reconstruction[J]. BMC Sports Sci Med Rehabil, 2022, 14(1):97.DOI:10.1186/s13102-022-00491-5.

[32]
Sonesson S, Kvist J, Ardern C, et al. Psychological factors are important to return to pre-injury sport activity after anterior cruciate ligament reconstruction:expect and motivate to satisfy[J]. Knee Surg Sports Traumatol Arthrosc, 2017, 25(5):1375-1384.DOI:10.1007/s00167-016-4294-8.

[33]
Faleide A, Magnussen LH, Bogen BE, et al. Association between psychological readiness and knee laxity and their predictive value for return to sport in patients with anterior cruciate ligament reconstruction[J]. Am J Sports Med, 2021, 49(10):2599-2606.DOI:10.1177/03635465211021831.

[34]
McPherson AL, Feller JA, Hewett TE, et al. Smaller change in psychological readiness to return to sport is associated with second anterior cruciate ligament injury among younger patients[J]. Am J Sports Med, 2019, 47(5):1209-1215.DOI:10.1177/0363546519825499.

[35]
Flannery SW, Murray MM, Badger GJ, et al. Early MRI-based quantitative outcomes are associated with a positive functional performance trajectory from 6 to 24 months post-ACL surgery[J]. Knee Surg Sports Traumatol Arthrosc, 2023, 31(5):1690-1698.DOI:10.1007/s00167-022-07000-8.

[36]
Brandsson S, Karlsson J, Sward L, et al. Kinematics and laxity of the knee joint after anterior cruciate ligament reconstruction:pre-and postoperative radiostereometric studies[J]. Am J Sports Med, 2002, 30(3):361-367.DOI:10.1177/03635465020300031001.

[37]
刘壮, 钱驿, 胥皞, 等. 中国男子篮球职业联赛球员前交叉韧带损伤后重返赛场的运动表现及相关因素分析[J]. 中国运动医学杂志, 2023, 42(1):19-24.DOI:10.3969/j.issn.1000-6710.2023.01.003.

[38]
Lindanger L, Strand T, Molster AO, et al. Return to play and long-term participation in pivoting sports after anterior cruciate ligament reconstruction[J]. Am J Sports Med, 2019, 47(14):3339-3346.DOI:10.1177/0363546519878159.

[39]
Glattke KE, Tummala SV, Chhabra A. Anterior cruciate ligament reconstruction recovery and rehabilitation:a systematic review[J]. J Bone Joint Surg Am, 2022, 104(8):739-754.DOI:10.2106/JBJS.21.00688.

Options
Outlines

/

〈 〉