Adult patients with ACL tears have greater tibial internal rotation in MRI compared to adolescent patients

Purpose To compare the anterior translation and internal rotation of tibia on magnetic resonance imaging (MRI) between adult and adolescent patients with anterior cruciate ligament (ACL) tears. Methods Patients who underwent isolated ACL reconstruction from January 2013 to May 2021 were retrospectively reviewed. The exclusion criteria included incomplete data, poor image quality, a prior ACL surgery, and concomitant fractures or other ligament injuries. The enrolled patients were divided into two groups based on their ages: an adult group (age > 19 years) and an adolescent group (15 to 19 years of age). Anterior tibial translation and femorotibial rotation were measured on MRI. A Student’s t-test was used for the statistical analysis comparing the adult and adolescent groups. Results A total of 365 patients (279 adults and 86 adolescents) were enrolled in the present study. The anterior tibial translation in the adult group (4.8 ± 4.4 mm) and the adolescent group (5.0 ± 4.2 mm) was not significantly different (p = 0.740). On the other hand, the tibial internal rotation in the adult group (5.6 ± 5.0 degree) was significantly greater compared to the adolescent group (4.2 ± 5.6 degree) (p = 0.030). The intraclass correlation coefficients (ICC) of the measured data from two independent observers showed excellent reliability (0.964 and 0.961 for anterior tibial translation and tibial internal rotation, respectively). Conclusion The adult patients with ACL tears exhibited significant greater tibial internal rotation compared to the adolescent patients, whereas the magnitude of the anterior tibial translation was similar in both groups. Care should be taken if clinicians plan to establish the cutoff point values for diagnosis of ACL tears using the femorotibial internal rotation angle.

Increase in Tibial Internal Rotation Due to Weight-bearing is a Key Feature to Diagnose Early-stage Knee Osteoarthritis: A Study with Upright Computed Tomography

Background The classification of knee osteoarthritis is an essential clinical issue, particularly in terms of diagnosing early knee osteoarthritis. However, the evaluation of three-dimensional limb alignment on two-dimensional radiographs is limited. This study evaluated the three-dimensional changes induced by weight-bearing in the alignments of lower limbs at various stages of knee osteoarthritis.Methods 45 knees of 25 patients (69.9 ± 8.9 years) with knee OA were examined in the study. CT images of the entire leg were obtained in the supine and standing positions using conventional CT and 320 low-detector upright CT, respectively. Next, the differences in the three-dimensional alignment of the entire leg in the supine and standing positions were obtained using 3D-3D surface registration technique, and those were compared for each Kellgren–Lawrence grade. Results Increased flexion, adduction, and tibial internal rotation were observed in the standing position, as opposed to the supine position. Kellgren–Lawrence grades 1 and 4 showed significant differences in flexion, adduction, and tibial internal rotation between two postures. Grades 2 and 4 showed significant differences in adduction, while grades 1 and 2, and 1 and 3 showed significant differences in tibial internal rotation between standing and supine positions.Conclusions Weight-bearing increased the three-dimensional deformities in knees with osteoarthritis. Particularly, increased tibial internal rotation was observed in patients with grades 2 and 3 compared to those with grade 1. The increase in tibial internal rotation due to weight-bearing is a key pathologic feature to detect early osteoarthritic change in knees undergoing osteoarthritis.

Both intraoperative medial and lateral soft tissue balances influence intraoperative rotational knee kinematics in bi-cruciate stabilized total knee arthroplasty: A retrospective investigation

Background Tibial internal rotation following total knee arthroplasty (TKA) is important in achieving favorable postoperative clinical outcomes. Studies have reported the effect of intraoperative soft tissue balance on tibial internal rotation in conventional TKA, no studies have evaluated the effects of soft tissue balance at medial or lateral compartments separately on tibial internal rotation in bi-cruciate stabilized (BCS) TKA. The purpose of this study was to clarify the relationship between medial or lateral component gaps and rotational knee kinematics in BCS TKA. Methods One hundred fifty-eight knees that underwent BCS TKA were included in this study. The intraoperative medial and lateral joint laxities which was defined as the value of component gap minus the thickness of the tibial component were firstly divided into two groups, respectively: Group M-stable (medial joint laxity, ≤ 2 mm) or Group M-loose (medial joint laxity, ≥ 3 mm) and Group L-stable (lateral joint laxity, ≤ 3 mm) or Group L-loose (lateral joint laxity, ≥ 4 mm). And finally, the knees enrolled in this study were divided into four groups based on the combination of Group M and Group L: Group A (M-stable and L-stable), Group B (M-stable and L-loose), Group C (M-loose and L-stable), and Group D (M-loose and L-loose). The intraoperative rotational knee kinematics were compared between the four Groups at 0°, 30°, 60°, and 90° flexion, respectively. Results The rotational angular difference between 0° flexion and maximum flexion in Group B at 30° flexion was significantly larger than that in Group A at 30° flexion (*p < 0.05). The rotational angular difference between 30° flexion and maximum flexion in Group B at 30° flexion was significantly larger than that in Group D at 30° flexion (*p < 0.05). The rotational angular differences between 30° or 90° flexion and maximum flexion in Group B at 60° flexion were significantly larger than those in Group A at 60° flexion (*p < 0.05). Conclusion Surgeons should pay attention to the importance of medial joint stability at midflexion and lateral joint laxities at midflexion and 90° flexion on a good tibial internal rotation in BCS TKA.

Effects of a 1-mm Difference in Bearing Thickness on Intraoperative Bearing Movement and Kinematics in Oxford Unicompartmental Knee Arthroplasty

Background: The choice of mobile bearing (MB) thickness is essential for obtaining successful results after mobile-bearing Oxford unicompartmental knee arthroplasty (UKA). This study aimed to investigate the effects of a 1-mm difference in bearing thickness on intraoperative MB movement and intraoperative knee kinematics in Oxford UKAs.Methods: We prospectively investigated the intraoperative MB movement and knee kinematics of 25 patients who underwent Oxford UKAs when surgeons didn’t know which bearing thickness to choose with 1-mm difference. A trial tibial component that was scaled every 2 mm was used to measure the intraoperative MB movement, and the tibial internal rotation relative to the femur and the knee varus angle was simultaneously evaluated using the navigation system as the knee kinematics. We separately evaluated sets of two MB thicknesses with 1-mm differences, and we compared the intraoperative parameters at maximum extension; 30º, 45º, 60º, and 90º flexion; and maximum flexion between the thicker MB (thick group) and the thinner MB (thin group).Results: The MB in the thin group was located significantly posteriorly at 90º flexion compared with that in the thick group; however, there were no differences at the other flexion angles. There was significantly less tibial internal rotation in the thin group at 90º flexion than that in the thick group; however, there were no differences at the other flexion angles. The knee varus angles in the thick group were significantly smaller than those in the thin group by approximately one degree at all angles other than at 30º and 45º flexion. Conclusion: The thicker MB could bring the less posterior MB movement and the more tibial internal rotation at 90º flexion, additionally the valgus correction angle in the thicker MB should be paid attention. These results could help surgeons to decide the thickness of MBs when they wonder the thickness of MB.

Effect of unplanned athletic movement on knee mechanics: a systematic review with multilevel meta-analysis

ObjectiveTo compare the effects of pre-planned and unplanned movement tasks on knee biomechanics in uninjured individuals.DesignSystematic review with meta-analysis.Data sourcesFive databases (PubMed, Google Scholar, Cochrane Library, ScienceDirect and Web of Science) were searched from inception to November 2020. Cross-sectional, (randomised) controlled/non-controlled trials comparing knee angles/moments of pre-planned and unplanned single-leg landings/cuttings were included. Quality of evidence was assessed using the tool of the Grading of Recommendations Assessment, Development and Evaluation working group.MethodsA multilevel meta-analysis with a robust random-effects meta-regression model was used to pool the standardised mean differences (SMD) of knee mechanics between pre-planned and unplanned tasks. The influence of possible effect modifiers (eg, competitive performance level) was examined in a moderator analysis.ResultsTwenty-five trials (485 participants) with good methodological quality (Downs and Black) were identified. Quality of evidence was downgraded due to potential risk of bias (eg, confounding). Moderate-quality evidence indicates that unplanned tasks evoked significantly higher external knee abduction (SMD: 0.34, 95% CI: 0.16 to 0.51, 14 studies) and tibial internal rotation moments (SMD: 0.51, 95% CI: 0.23 to 0.79, 11 studies). No significant between-condition differences were detected for sagittal plane mechanics (p>0.05). According to the moderator analysis, increased abduction moments particularly occurred in non-professional athletes (SMD: 0.55, 95% CI: 0.14 to 0.95, 5 studies).ConclusionUnplanned movement entails higher knee abduction and tibial internal rotation moments, which could predispose for knee injury. Exercise professionals designing injury-prevention protocols, especially for non-elite athletes, should consider the implementation of assessments and exercises requiring time-constrained decision-making.PROSPERO registration numberCRD42019140331.

Both Intraoperative Medial and Lateral Soft Tissue Balances Influence Intraoperative Rotational Knee Kinematics in Bi-Cruciate Stabilized Total Knee Arthroplasty: A Retrospective Investigation.

BackgroundTibial internal rotation following total knee arthroplasty (TKA) is important in achieving favorable postoperative clinical outcomes. Studies have reported the effect of intraoperative soft tissue balance on tibial internal rotation in conventional TKA, however, its effect on bi-cruciate stabilized (BCS) TKA has not reported enough. Furthermore, although studies have shown that both medial and lateral soft tissue balances are important for a good tibial internal rotation, no studies have evaluated the effects of soft tissue balance at medial or lateral compartments separately on tibial internal rotation in BCS TKA. The purpose of this study was to clarify the relationship between medial or lateral component gaps and rotational knee kinematics in BCS TKA.MethodsOne hundred fifty-eight knees that underwent BCS TKA were included in this study. They were divided into two groups according to the medial or lateral joint laxities, which was defined as the value of component gap minus the selected thickness of the tibial component at 30°, 60°, and 90° flexion, respectively: Group M-stable (medial joint laxity, ≤2 mm) or Group M-loose (medial joint laxity, ≥3 mm) and Group L-stable (lateral joint laxity, ≤3 mm) or Group L-loose (lateral joint laxity, ≥4 mm). The intraoperative rotational knee kinematics was compared between Group M-stable and Group M-loose or between Group L-stable and Group L-loose at each angle, respectively.ResultsThe rotational angular difference between 30° flexion and maximum flexion was significantly larger in Group M-stable at 30° flexion than that in Group M-loose at 30° flexion. The rotational angular difference between 60° flexion and maximum flexion was significantly larger in Group L-loose at 60° flexion than that in Group L-stable at 60° flexion. The rotational angular difference between 60° flexion and maximum flexion was significantly larger in Group L-loose at 90° flexion than that in Group L-stable at 90° flexion.ConclusionSurgeons should pay attention to the importance of medial joint stability at midflexion and lateral joint laxities at midflexion and 90° flexion on a good tibial internal rotation from midflexion to deep flexion in BCS TKA.

Influence of a Foot Insole for a Down Syndrome Patient with a Flat Foot: A Case Study

Background and Objectives: Patients with Down syndrome have many orthopedic problems including flat foot. Insertion of an insole for a flat foot provides support to the medial longitudinal arch; thus, insole therapy is often used to treat a flat foot. However, the influence of an insole insertion on the knee joint kinematics for a patient with Down syndrome is unknown. This study aimed to elucidate the influence of an insole for a flat foot on the knee kinematics during gait for a patient with Down syndrome. Materials and Methods: The subject was a 22-year-old male with Down syndrome who had a flat foot. The knee joint angle during the gait was measured using a 3D motion capture system that consisted of eight infrared cameras. Results: The gait analysis demonstrated a reduction in the knee flexion angle during double knee action. The knee valgus and tibial internal rotation angles also decreased during the loading response phase while wearing shoes that contained the insole. Conclusions: As the angle of the knee joint decreased during the gait, it was considered that the stability of the knee joint improved by inserting the insole. In particular, there was a large difference in the tibial internal rotation angle when the insole was inserted. It is thus hypothesized that the insole contributes to the rotational stability of the knee joint. This study suggests that knee stability may improve and that gait becomes more stable when a Down syndrome patient with a flat foot wears an insole.