Assessment of Anterior Knee Pain due to Maltracking of Patella - Essay Example

Assessment of Anterior Knee Pain due to Maltracking of Patella Introduction: In view of the frequent problems involving the patellofemoral joint, it is interesting and remarkable that for much of the time, the articulating surfaces of this joint are not in contact with each other. While there is no bone-on-bone contact with the femur in full knee extension or while standing or walking on the level ground, the extent of contact between the patella and the femur appears to vary depending on a number of factors, such as, the angle of knee flexion, the location of the contact, the surface area of contact, and the patellofemoral joint reaction force (Ficat and Hungerford, 1977, 85-109). Background Information: The angle of knee flexion is a very important parameter to be considered in the understanding of the pathophysiology of patellar maltracking. As the knee flexion proceeds, the quadriceps vector becomes more perpendicular, and the force on the patella gradually increases. This increasing force is transmitted by the quadriceps and is somewhat dissipated by the increased patellofemoral contact with increasing flexion. However, because the force increases more rapidly that the available surface area, with increasing flexion, the stress on the patella increases in a significant manner. In this scenario, any muscle imbalance between the lateral and medial quadriceps muscles can affect the patellar alignment and pressure distribution in the lower flexion angles of less than 60 degrees resulting in rotation of the patella in the coronal plane. At higher flexion angles, imbalances are likely to produce a tilt of the patella in the sagittal plane (Lopis and Padron, 2007, 27-43). Patellofemoral joint reaction force causes compression of the patellofemoral joint. These forces are caused by the increase in patellar and quadriceps tendon tension and the increase in the acquity of the Q angle that occurs during knee flexion. An imbalance of the quadriceps that produces a decrease in the magnitude or direction of the tension of the VMO may result in significant displacement of the patella laterally, placing the patellofemoral joint reaction force almost entirely on the lateral patellar facet. Considering the forces that are generated within the lateral patellofemoral joint, it is easy to envisage that an increase in these shearing and compression forces has the potential to contribute to patellofemoral pain. These forces are readily accentuated by physical activity. Miscongruency of the articular surfaces would ultimately lead to articular cartilage changes and eventually loss of articular cartilages attributable to excessive pressure on the lateral patella facet. The distal central aspect of the patella may undergo degeneration related to abnormal shear stress and abnormally deficient contact, early in the knee flexion. Ultimately, this process may culminate into pain in the anterior knee from the articular cartilage changes and resulting subchondral bone irritation from synovitis and inflammatory response within the knee joint (Hussain, Lam, Slack, Arya, and Compson, 2003, 105). Aim: To compare the efficacy of conventional radiologic investigation versus the proposed Biomedex therapy by a randomized controlled trial. Objective: To investigate the efficacy and reliability of Biodex investigation of patellar maltracking as opposed to that of conventional radiological investigation. Literature Review: Anterior knee pain is frequently encountered in clinical practice related to sports injury. This is often due to patellar maltracking. This is a serious condition that may lead to chondromalacia of the patella. It is difficult to determine the position of the patella between 0 to 30 degrees of knee flexion. Conventional radiologic examination often fails to detect maltracking. However, computed tomography and magnetic resonance imaging have been introduced to detect the cases to image the knee joint abnormalities. These high-end investigations, however, are not available always on a day to day practice, and they are expensive. Motion triggered dynamic magnetic resonance imaging is another alternative that has a better diagnostic accuracy, but cost is a great hindrance to its feasibility (Fulkerson, 1994, 124-132). The dynamic restraints of the patellofemoral joint are the quadriceps muscle and the extensor mechanism. The tension provided by the soft tissues can prevent the patella from slipping laterally. Excessively tight lateral structures or deficient medial structures may increase the force that is directed laterally. This would result in maltracking of the patella. As the lateral structures, such as vastus lateralis, iliotibial band, or lateral retinaculum may be tight, likewise, the medial structures may be loose from stretching after repeated dislocations or from severe wasting and weakness of the vastus medialis. During knee flexion and extension, the patella must be maintained in the intercondylar groove. As has been mentioned, the proper patellofemoral alignment is the result of both static and dynamic factors. Any change in the balance between static and dynamic components may produce maltracking and result in patellofemoral pain. Athletes who present with anterior knee pain without a history of significant trauma or dislocation should be suspected of having underlying patellofemoral malalignment as the primary problem. The problem that this author offers to deal with in this proposal is that of patellofemoral pain syndrome that has been chosen to describe the commonly encountered complaint of anterior knee pain since it does not signify a particular pathological process. This entity may have a multifactorial pathology, but this proposal will concentrate on what is probably the most important common cause of this problem, lateral patellar tracking or maltracking. In the previous section, it has been explored about how medial patellofemoral joint (PFJ) hypopressure and lateral PFJ hyperpressure would eventually cause joint damage. When vastus medialis oblique weakness is incriminated in its causation, it is important to know how a therapy directed at vastus medialis strengthening might relieve these symptoms. Imbalance between the functional strengths vastus lateralis and vastus medialis has also been identified as being contributory to lateral patellar maltracking. The increased Q angle is based on anatomical variances. The increased angle may increase the lateral valgus vector force, thus encouraging lateral tracking resulting in patellofemoral pain. Rehabilitation considerations inclyude strengthening vastus medialis obliquous to attempt to counteract the lateral valgus vector force. The VMO insufficiency is a major precipitating factor for patellar maltracking (Laurin, Levesque, Dussault et al., 1978, 55-60). The VMO normally serves as a dynamic stabilizer of the patella. It is normally tonically active throughout the entire range of motion. In athletes with patellofemoral pain, however, it is phasically active and tends to lose its fatigue capabilities. In addition, in normal individuals, the vastus medialis obliquus (VMO) to vastus lateralis (VL) ratio has been demonstrated to be 1:1. In contrast in individuals with patellofemoral pain, the ratio is less than 1:1. It has been suggested that this alteration in the VMO: VL ratio contributes to the patellofemoral pain (Brossman, Muhle, Schroder et al., 1993, 205-212). Anterior knee pain is frequently encountered in clinical practice related to sports medicine. This results from patellofemoral malalignment with a potential to result in chondromalacia of the patella and anterior knee pain. Weakness of the vastus medialis obliquus is considered to be the single most important factor causing momentary patellar subluxation. By natural coherence, the passive stabilizing structures are usually more extensive and stronger on the lateral than on the medial side. On the whole active stabilization of the patella during patellofemoral movements during different ranges of knee excursions are provided by quadriceps components, the VL on the lateral and VM and its components on the medial side. The fibers of the vastus medialis are divided functionally into two compartments, the vastus medialis longus and the vastus medialis obliquus. The VMO, however, does not play a role in the active extension. While designing the therapy for such conditions, it is important to remember that VMO is the only active stabilizer of the patella. Therefore, the management of patellar maltracking should be conservative, although surgical interventions are reserved for the patients who do not respond effectively. Adequate conservative treatment would consist of intensive functional vastus medialis rehabilitation together with the use of a brace. In these patients, routine clinical examination reveals nothing. The VMO is assessed by asking the patient to hold the knees actively at 45 degrees of flexion. In patients with weakness or atrophy of VMO, there would be a visible and palpable lack of muscular tissue at the upper medial border of the patella (Katchburian, Bull, Shih, Heatley, and Amis, 2003, 241-259). Conventional Radiology: In the office, a standard radiographic evaluation is usually performed. This includes a standard anteroposterior view of both legs in full extension to look for angular changes and to compare the height of the joint space. Many a times, this view is non-revealing, and then the clinician chooses a 45-degree flexion, posteroanterior weight-bearing view to identify subtle joint space narrowing. Since a radiographic examination is done in a static position and patellar maltracking occurs in a mobile joint, these radiographic examinations are less than ideal. Therefore, there is always a fair chance that the clinician fails to reach a diagnosis both by clinical examination and a radiologic examination of the joint. As a result to get a clearer picture about what has occurred in the joint, the clinician supplements this radiological investigation with some more views of the joint. A non-weight-bearing lateral view with 45 degree flexion in which the posterior femoral condyles overlap, an axial view of both the patellae to evaluate patellar alignment, an anteroposterior, knee flexion view to outline the femoral intercondylar notch also should be obtained (Newberg and Seligson, 1980, 57-61). More often what happens is many cases remain undetected with such protocols in such that patients with otherwise normal standard radiograph can demonstrate an active lesion with other means of imaging such as magnetic resonance imaging. Sparing details, it can be said that this process involves radiation exposure without much perceived benefit, and the magnetic resonance imaging is not cost effective enough to be employed in routine clinical practice, and facilities are not always available. Therefore this investigative protocol is not all fulfilling, and there is a perceived gap. Biodex is an apparatus which can detect individuals groups of muscles. This proposal proposes to find out an alternative to existing practice that may be safe, effective, reliable, and practical alternative to the existing practice. This offers isokinetic resistance to the suspected group of muscles and measures the patient output force. This is a safe and objective way to quantify physical impairments in any group of muscle. Research has shown high correlation to function in this test. Isokinetic testing is proclaimed to be the standard for muscle and joint assessment (Merchant, Mercer, Jacobsen, Cool, 1974, 1391-1396). In this study, patients with patellar maltracking would undergo conventional radiological examination, and the other group will be subjected to Biodex investigations to detect the weak groups of muscles in the exercise laboratory. Sample Size: About 15 patients will be recruited from the sports physiology outpatient department. Ethical Clearance: This proposal would be submitted to the ethical review committee, and after their clearance, all patients would be explained about this study with all risks and benefits explained in detail. Privacy would be ensured, and both verbal and written informed consent would be taken. The patients will be at their free will to pull off from the investigation at any given point in time. The recruits would be given chance to ask questions. Methodology: A detailed history would be taken from each of the patients. A thorough knee examination would be undertaken. Once the provisional history and physical suggests the diagnosis, the all patients would be subjected to conventional radiography by Merchant's view. Then the patients would be referred to the exercise laboratory where Biodex testing would be performed after explaining the test. This machine would detect in a noninvasive way the weak groups of muscles. Since VMO weakness has been implicated pathologically in causation of patellar maltracking, this machine would be able to detect VMO weakness in the positive cases (Elias and White, 2004, 543-557). History, physical examination, results of the conventional radiologic investigations, and result of Biodex investigation would be recorded separately for each patient. The inclusion criteria would be any patient suspected to be having patellar maltracking from history. The exclusion criteria would be those suspected to be having other pathologies and those who would have other associated pathologies in the knee joint by radiologic investigations, because they may constitute confounding variables that may compromise the reliability and validity of the data. The end point would be the diagnosis of patellar maltracking for which the blinded observer would advise physiotherapy for VMO exercise in the exercise laboratory. Imaging Protocol: A standard office radiographic evaluation will be performed. This would include a standard anteroposterior view of both knees in full extension to look for Q angle changes and to compare the height of the joint space. If this view is non-revealing, a 45-degree flexion, posteroanterior weight-bearing view to identify subtle joint space narrowing will be done (McNally EG, et al.,2002). Data Collection: The demographic data of the patients will be collected. The relevant findings from the history and physical would be recorded as provisional diagnosis. Both the positive and negative findings in conventional radiologic examination will be recorded. The cost from the records for the radiologic examination will also be recorded as against the number of views required to reach the diagnosis. All these patients will be subjected to Biodex test in the exercise lab as an additional test, and the findings will be recorded for each patient. These data will be tabulated in an organized manner. Statistical Analysis: For data analysis, the nonparametric Wilcoxon signed rank test would be used to compare, history, physical examination, radiologic data, and Biodex data. For comparison of the radiologic data and the Biodex data, a Mann-Whitney U-test will be used. The differences between the radiologic parameters and Biodex parameters would be tested for statistical significance. In each subject, the linear regression coefficients each of the radiologic parameters will be calculated for each of the Biodex parameters. The P values for the comparison of the regression coefficients and the linear regression for the mean values of the corresponding parameters will be calculated. A cost comparison analysis of both the means will also be done (Sachs, 1984, 707). Results: The results will be expressed in an organized manner, and as expected, these results would reveal the benefits of Biodex as opposed to conventional radiologic investigations. Implications: If the hypothesis is proved, Biodex could prove to be a more effective and cost effective means of detecting VMO weakness that is instrumental in patellar maltracking in comparison to radiography that is more expensive and has hazards of radiation associated with it. Apart from that, this has limitations in terms of diagnostic sensitivity and reliability. Due to these reasons and due to the fact that Biodex is better option, in future, provided the hypothesis is proved, these patients can be sent directly to the Exercise Lab for this test and physiotherapy in the same setting increasing convenience. References Brossman J, Muhle C, Schroder C, et al., 1993. Patellar tracking patterns during active and passive knee extension: evaluation with motion-triggered cine MR imaging. Radiology :187:205-212. Elias, DA and White, LM, 2004. Imaging of patellofemoral disorders. Clin Radiol; 59(7): 543-57. Ficat RP, Hungerford DS. Disorders of the patellofemoral joint. Baltimore, Md: Williams & Wilkins, 1977; 85-109. Fulkerson JP., 1994 Patellofemoral pain disorders: evaluation and management. J American Academy of Orthop Surg. 1994:2:124-132. Hussain, SA, Lam, F., Slack, R., Arya, A., and Compson, J., (2003). Articular Surface Wear In Patello-Femoral Maltracking. J Bone Joint Surg Br Proceedings; 85-B: 105. Katchburian, MV, Bull, AM, Shih, YF, Heatley, FW, and ,Amis, AA., 2003. Measurement of patellar tracking: assessment and analysis of the literature. Clin Orthop Relat Res; (412): 241-59. Laurin CA, Levesque HP. Dussault R. et al., 1978. The abnormal lateral patellofemoral angle. J Bone Joint Surg Am:60-A:55-60. Lopis, EL and Padron, M., 2007. Anterior knee pain. Eur J Radiol; 62(1): 27-43. Merchant AC, Mercer RL, Jacobsen RH, Cool CR., 1974. Roentgenographic analysis of patellofemoral congruence. J Bone Joint Surg Am :56-A: 139 1-1396 McNally EG, et al.,2002. Role of magnetic resonance imaging in the clinical management of the acutely locked knee. Skeletal Radiol;31:570-573. Newberg AH. Seligson D., 1980. The patellofemoral joint: 30'. 60' and 90' views. Radiology:137:57-61 Sachs L. Applied statistics: a handbook of techniques. Berlin, Germany: Springer, 1984. 707. Read More