Three-Dimensional In Vivo Patellofemoral Kinematics and Contact Area of Anterior Cruciate Ligament-Deficient and -Reconstructed Subjects Using Magnetic Resonance Imaging

Department of Mechanical Engineering, Sogang University, Seoul, Republic of Korea.
Arthroscopy The Journal of Arthroscopic and Related Surgery (Impact Factor: 3.21). 11/2009; 25(11):1214-23. DOI: 10.1016/j.arthro.2009.05.013
Source: PubMed


The purpose of this study was to test whether (1) the 3-dimensional in vivo patellofemoral kinematics and patellofemoral contact area of anterior cruciate ligament (ACL)-deficient knees are different from those of normal, contralateral knees and (2) ACL reconstruction restores in vivo patellofemoral kinematics and contact area.
Ten ACL-deficient knees and twelve ACL-reconstructed knees, as well as the contralateral uninjured knees, were tested. Magnetic resonance imaging was performed at full extension and 40 degrees of flexion under simulated partial weight-bearing conditions. Six-degrees of freedom patellofemoral kinematics, patellofemoral contact area, and contact location were analyzed by use of magnetic resonance image-based 3-dimensional patellofemoral knee models.
The patella in the ACL-deficient knees underwent significantly more lateral tilt during flexion (P < .05) and tended to translate more laterally (P = .083) than the patella in contralateral knees. After ACL reconstruction, no kinematic parameters were significantly different from those in contralateral knees. The patellofemoral contact areas of ACL-deficient knees at both the extended and flexed positions (37 +/- 22 mm(2) and 357 +/- 53 mm(2), respectively) were significantly smaller than those of contralateral knees (78 +/- 45 mm(2) and 437 +/- 119 mm(2), respectively) (P < .05). After reconstruction, the patellofemoral contact area of ACL-reconstructed knees in the extended position (86 +/- 41 mm(2)) was significantly larger (P < .05) than that of contralateral knees (50 +/- 34 mm(2)), but no difference was detected in the flexed position. Reproducibility of all patellofemoral kinematic parameters, contact centroid translation, and contact area showed coefficients of variation of less than 6.8%.
ACL injuries alter patellofemoral kinematics including patellar tilt and patellar lateral translation, but ACL reconstruction with hamstring or allograft restores altered patellar tilt. ACL injuries reduce the patellofemoral contact area at both the extended and flexed positions, but ACL reconstruction enlarges the patellofemoral contact area at extension and restores the normal contact area at low angles of flexion.
Level III, case-control study.

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    • "Therefore small rotational movements were still possible and might have influenced the patellar lateralization by external tibial rotation (Hsieh et al., 1998). VM atrophy and weakness are frequently observed in patients with ACL injuries and are associated with patellar mal-tracking potentially leading to PF-OA (Baugher et al., 1984; Hart et al., 2012; Shin et al., 2009). Studies in humans and human cadavers report changes in lateral tracking and rotation of the patella in the presence of isolated VM weakness , suggesting that VM weakness might be an independent risk factor for alterations in PF kinematics (Goh et al., 1995; Lin et al., 2010). "
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    ABSTRACT: Background: Anterior cruciate ligament deficiency and quadriceps muscle weakness are considered to be important risk factors for aberrant patellar tracking and subsequent patellofemoral osteoarthritis. However, data from in vivo experiments looking at dynamic patellar joint kinematics and muscle force are scarce. Therefore, the purpose of this study was to evaluate the effects of anterior cruciate ligament transection and loss of vastus medialis force on patellar tracking in the rabbit knee in vivo. Methods: Eight skeletally mature New Zealand White Rabbits, weighing 6.0kg (0.6kg standard deviation) were used. The experimental trials consisted of active, concentric and eccentric movements of the knee joint. Measurements were performed with the intact, the anterior cruciate ligament deficient, and the vastus medialis transected knee. Patellofemoral kinematics (shift, rotation) were quantified from high speed video. Findings: Following anterior cruciate ligament transection, patellar tracking occurred more laterally, and caused a significant lateral rotation of the patella. The addition of vastus medialis transection did not alter patellar tracking or rotation significantly for any of the force-matched experimental conditions. Interpretation: The loss of the anterior cruciate ligament results in lateral patellar shift and rotation while the loss of vastus medialis muscle force does not affect patellar tracking or rotation in the anterior cruciate ligament deficient knee. We suggest that the current results should be considered carefully in future interpretations of knee extensor imbalance. More research is needed to describe the contribution of vastus medialis muscle strength to medial patellofemoral stability and confirm these results in the human knee.
    Clinical biomechanics (Bristol, Avon) 05/2014; 29(5). DOI:10.1016/j.clinbiomech.2014.03.001 · 1.97 Impact Factor
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    • "A change in knee joint angle and level of effort affects the orientation of the tendon and the position of the bones and ligaments relative to one another with a direct effect on moment-arm (Tsaopoulos et al. 2006). In addition, evidence indicates that ACL reconstruction effects on patellofemoral contact area vary depending on joint angle (Shin et al. 2009) while increasing contraction intensity increases moment-arms by 20 –22% (Tsaopoulos et al. 2006; Sheehan 2007). "
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    ABSTRACT: The purpose of this study was to examine the moment-arm and cross-sectional area (CSA) of the patellar tendon (PT) and the hamstrings after anterior cruciate ligament (ACL) reconstruction. The right knee of five males who underwent ACL reconstruction with a PT graft and five age-matched controls was scanned using magnetic resonance image scans. Based on three-dimensional (3D) solids of the PT, CSAs and moment-arms of semitendinous (ST), biceps femoris (BF) long head and semimembranosus (SM) were estimated. Analysis of variance indicated no significant group differences in muscle moment-arms (p>0.05). 3D moment-arms of PT, ST and BF were significantly lower than the corresponding 2D values (p < 0.05). The ACL group displayed a significantly higher maximum BF CSA, a lower ST CSA (p < 0.05) but similar PT and SM CSAs compared with controls. It is concluded that any alterations in PT properties 1 year after harvesting do not affect knee muscle moment-arms compared with age-matched controls. Moment-arm estimation differed between 3D and 2D data, although it did not affect comparisons between ACL reconstruction group and controls. Design of rehabilitation programmes should take into consideration a potential alteration in hamstring morphology following surgery with a PT graft.
    Computer Methods in Biomechanics and Biomedical Engineering 01/2014; 18(10). DOI:10.1080/10255842.2013.869323 · 1.77 Impact Factor
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    • "Patients with evident fractures or significant hydrops were excluded, but patients who would have had an anterior cruciate ligament (ACL) deficiency were not. As is now known, an ACL deficiency induces an increased patellar angle of approximately 3° [16]. We found that the difference between measurements must be at least 5° to be a real difference, so a difference of only 3° may not be so relevant. "
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    ABSTRACT: The objective of this study is to evaluate patellofemoral joint imaging on magnetic resonance imaging (MRI) in asymptomatic subjects to assess normal values and to test statistical correlation and reliability of MRI scan. An analysis of 51 standard MRI examinations was performed. Sulcus angle (SA), patellar axis (PA), lateral patellofemoral angle (LPFA), and lateral patellofemoral length (LPL) were measured. None of the patients suffered from patellofemoral complaints. Patients with patella alta and significant hydrops were excluded. The measurements were assessed with a 2-week interval by two raters under blinded conditions. Statistical analysis was applied by an independent analyst. The mean SA referenced 142.4 ± 6.9°, PA 5.3 ± 3.8°, LPFA 13 ± 4.4°, and LPL 0.8 ± 2.9 mm. Inter-observer variability showed high correlation for LPL and PA, as the repeatability coefficient was high (LPL; 1.49 (LN), 5.7 (ST) and PA; 4.1 (LN), 5.8 (ST). Also, intra-observer variability showed good correlation for LPL and PA. The results represent patellofemoral values in the normal population. They indicate that MRI is a reliable imaging technique to determine lateral patellofemoral length and patellar axis. Lateral patellofemoral angle and sulcus angle showed a poor correlation and should not be used for decision making. Development of diagnostic criteria in a consecutive series of patients and a universally applied "gold" standard, Level II.
    Knee Surgery Sports Traumatology Arthroscopy 04/2011; 19(10):1735-9. DOI:10.1007/s00167-011-1508-y · 3.05 Impact Factor
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