Physical examination of the knee
- Anthony Beutler, MD
Anthony Beutler, MD
- Associate Professor of Family Medicine
- Uniformed Services University
- Antoin Alexander, MD
Antoin Alexander, MD
- David Grant Medical Center
- Travis AFB CA Family Medicine Residency Program
- Section Editor
- Karl B Fields, MD
Karl B Fields, MD
- Editor-in-Chief — Primary Care Sports Medicine (Adolescents and Adults)
- Section Editor — Biomechanics, Rehabilitation, and Recovery; Sports-Related Injuries; Symptom Assessment and Physical Examination
- Professor of Family Medicine and Sports Medicine
- University of North Carolina at Chapel Hill
- Deputy Editor
- Jonathan Grayzel, MD, FAAEM
Jonathan Grayzel, MD, FAAEM
- Senior Deputy Editor — UpToDate
- Deputy Editor — Emergency Medicine (Adult and Pediatric)
- Deputy Editor — Primary Care Sports Medicine (Adolescents and Adults)
- Assistant Professor of Emergency Medicine
- University of Massachusetts Medical School
Knee pain and other knee-related complaints are a common reason for visits to primary care clinics and emergency departments. An effective and efficient evaluation of the patient with knee-related complaints depends upon an understanding of the knee's anatomy and function, and the proper performance of an appropriately focused physical examination.
The examination of the knee is reviewed here. A brief review of knee anatomy and biomechanics is also provided. The work-up of patients with knee-related complaints and specific knee injuries and conditions are discussed separately. (See "Approach to the adult with knee pain likely of musculoskeletal origin" and "Approach to the adult with unspecified knee pain".)
Bones and articulations — The knee joint contains four bones—femur, tibia, patella, and fibula—and consists of three compartments—the medial tibiofemoral, lateral tibiofemoral, and patellofemoral—all sharing a common synovial cavity (picture 1 and picture 2 and figure 1 and picture 3 and picture 4 and picture 5). The knee has three articulations: medial and lateral tibiofemoral and patellofemoral. The tibiofemoral articulations connect the distal femur, which broadens to form the medial and lateral femoral condyles, and the tibia. The tibia is relatively flat, but the sloped menisci permit a tight articulation with the convex femoral condyles. The femoral condyles are separated by an intercondylar fossa, also called the femoral groove or femoral trochlea.
The patella is a sesamoid bone embedded in the quadriceps tendon that articulates with the trochlear groove of the femur (picture 6 and figure 2). Its function is to increase the mechanical advantage of the quadriceps. The fibular head lies within the capsule of the knee but is not normally involved as a weight-bearing surface. The joint lines are formed by the femoral condyles and the tibial plateaus.
Structures providing support and stability — Several soft tissues contribute to knee stability and provide cushioning within the joint. The parts of the tibia and femur contained within the knee joint are lined with shock absorbing hyaline cartilage. Disc-shaped lateral and medial menisci provide additional shock absorption and distribute forces across the joint. The anterior and posterior cruciate ligaments provide stability with anterior and posterior movements and with flexion and extension; the medial and lateral collateral ligaments provide support in their respective planes. Other structures that contribute to knee stability include the iliotibial band and parts of the posterolateral corner.
- Bleday RM, Fanelli GC, Giannotti BF, et al. Instrumented measurement of the posterolateral corner. Arthroscopy 1998; 14:489.
- Gollehon DL, Torzilli PA, Warren RF. The role of the posterolateral and cruciate ligaments in the stability of the human knee. A biomechanical study. J Bone Joint Surg Am 1987; 69:233.
- Grood ES, Noyes FR, Butler DL, Suntay WJ. Ligamentous and capsular restraints preventing straight medial and lateral laxity in intact human cadaver knees. J Bone Joint Surg Am 1981; 63:1257.
- Griffith CJ, LaPrade RF, Johansen S, et al. Medial knee injury: Part 1, static function of the individual components of the main medial knee structures. Am J Sports Med 2009; 37:1762.
- Griffith CJ, Wijdicks CA, LaPrade RF, et al. Force measurements on the posterior oblique ligament and superficial medial collateral ligament proximal and distal divisions to applied loads. Am J Sports Med 2009; 37:140.
- Covey DC. Injuries of the posterolateral corner of the knee. J Bone Joint Surg Am 2001; 83-A:106.
- Claes S, Vereecke E, Maes M, et al. Anatomy of the anterolateral ligament of the knee. J Anat 2013; 223:321.
- Hennigan SP, Schneck CD, Mesgarzadeh M, Clancy M. The semimembranosus-tibial collateral ligament bursa. Anatomical study and magnetic resonance imaging. J Bone Joint Surg Am 1994; 76:1322.
- Van den Bergh FR, Vanhoenacker FM, De Smet E, et al. Peroneal nerve: Normal anatomy and pathologic findings on routine MRI of the knee. Insights Imaging 2013; 4:287.
- Hauzeur JP, Mathy L, De Maertelaer V. Comparison between clinical evaluation and ultrasonography in detecting hydrarthrosis of the knee. J Rheumatol 1999; 26:2681.
- Hong BY, Lee JI, Kim HW, et al. Detectable threshold of knee effusion by ultrasonography in osteoarthritis patients. Am J Phys Med Rehabil 2011; 90:112.
- Kane D, Balint PV, Sturrock RD. Ultrasonography is superior to clinical examination in the detection and localization of knee joint effusion in rheumatoid arthritis. J Rheumatol 2003; 30:966.
- Ferber R, Kendall KD, McElroy L. Normative and critical criteria for iliotibial band and iliopsoas muscle flexibility. J Athl Train 2010; 45:344.
- Beutler AI, Cooper LW, Kirkendall DT, Garrett WE Jr. Electromyographic Analysis of Single-Leg, Closed Chain Exercises: Implications for Rehabilitation After Anterior Cruciate Ligament Reconstruction. J Athl Train 2002; 37:13.
- Malanga GA, Andrus S, Nadler SF, McLean J. Physical examination of the knee: a review of the original test description and scientific validity of common orthopedic tests. Arch Phys Med Rehabil 2003; 84:592.
- Harilainen A. Evaluation of knee instability in acute ligamentous injuries. Ann Chir Gynaecol 1987; 76:269.
- Garvin GJ, Munk PL, Vellet AD. Tears of the medial collateral ligament: magnetic resonance imaging findings and associated injuries. Can Assoc Radiol J 1993; 44:199.
- McAllister DR, Petrigliano FA. Diagnosis and treatment of posterior cruciate ligament injuries. Curr Sports Med Rep 2007; 6:293.
- Lopez-Vidriero E, Simon DA, Johnson DH. Initial evaluation of posterior cruciate ligament injuries: history, physical examination, imaging studies, surgical and nonsurgical indications. Sports Med Arthrosc 2010; 18:230.
- Wind WM Jr, Bergfeld JA, Parker RD. Evaluation and treatment of posterior cruciate ligament injuries: revisited. Am J Sports Med 2004; 32:1765.
- Solomon DH, Simel DL, Bates DW, et al. The rational clinical examination. Does this patient have a torn meniscus or ligament of the knee? Value of the physical examination. JAMA 2001; 286:1610.
- Kopkow C, Freiberg A, Kirschner S, et al. Physical examination tests for the diagnosis of posterior cruciate ligament rupture: a systematic review. J Orthop Sports Phys Ther 2013; 43:804.
- Rubinstein RA Jr, Shelbourne KD, McCarroll JR, et al. The accuracy of the clinical examination in the setting of posterior cruciate ligament injuries. Am J Sports Med 1994; 22:550.
- Daniel DM, Stone ML, Barnett P, Sachs R. Use of the quadriceps active test to diagnose posterior cruciate-ligament disruption and measure posterior laxity of the knee. J Bone Joint Surg Am 1988; 70:386.
- Strauss EJ, Ishak C, Inzerillo C, et al. Effect of tibial positioning on the diagnosis of posterolateral rotatory instability in the posterior cruciate ligament-deficient knee. Br J Sports Med 2007; 41:481.
- Jung YB, Lee YS, Jung HJ, Nam CH. Evaluation of posterolateral rotatory knee instability using the dial test according to tibial positioning. Arthroscopy 2009; 25:257.
- Alam M, Bull AM, Thomas Rd, Amis AA. Measurement of rotational laxity of the knee: in vitro comparison of accuracy between the tibia, overlying skin, and foot. Am J Sports Med 2011; 39:2575.
- Hoppenfield S. Physical examination of the knee. In: Physical Examination of the Spine and Extremities, Prentice Hall, Upper Saddle River 1976.
- Smith BW, Green GA. Acute knee injuries: Part I. History and physical examination. Am Fam Physician 1995; 51:615.
- Oberlander MA, Shalvoy RM, Hughston JC. The accuracy of the clinical knee examination documented by arthroscopy. A prospective study. Am J Sports Med 1993; 21:773.
- Hing W, White S, Reid D, Marshall R. Validity of the McMurray's Test and Modified Versions of the Test: A Systematic Literature Review. J Man Manip Ther 2009; 17:22.
- Ben-Galim P, Steinberg EL, Amir H, et al. Accuracy of magnetic resonance imaging of the knee and unjustified surgery. Clin Orthop Relat Res 2006; 447:100.
- Bones and articulations
- Structures providing support and stability
- Structures involved in knee extension
- Popliteal fossa and structures involved in knee flexion
- Bursa and cystic structures
- Neurovascular structures
- TIPS FOR A PRODUCTIVE EXAMINATION
- Observe gait
- Swelling and ecchymosis
- Skin changes
- General approach
- Joint line palpation
- - Lateral joint line
- - Medial joint line
- Anterior knee off the joint line
- Posterior knee
- Skin temperature
- DETECTION OF AN EFFUSION
- RANGE OF MOTION AND MUSCLE FLEXIBILITY
- NEUROVASCULAR ASSESSMENT
- MOTOR FUNCTION AND STRENGTH
- Quadriceps strength
- Hamstring strength
- Functional strength tests
- ASSESSING JOINT STABILITY
- Valgus stress test for medial instability
- Varus stress test for lateral instability
- Tests for ACL injury and anterior stability
- Tests for PCL injury and posterior stability
- - Posterior drawer test
- - Posterior sag sign
- - Quadriceps active test
- - Dial test
- SPECIAL TESTS FOR SPECIFIC CONDITIONS
- A word of caution
- Tests for patellofemoral pain
- Tests for meniscal tear
- Tests for iliotibial band syndrome
- SUMMARY AND RECOMMENDATIONS