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Examination of the knee for MRCS OSCE
ORTHOPAEDICS e IV: LOWER LIMB
Examination of the knee for MRCS OSCE
outcomes for the patient and your exam mark. Sound knowledge of anatomy is essential but this is beyond the scope of this article, the authors recommend thoroughly revising knee anatomy prior to learning the clinical examination.
Daniel Blyth
History
Aadil Mumith
All clinical examinations should start with a thorough history of the presenting complaint. Once you are aware how and when the problem started you can tailor your history and physical examination to the patient. The presence of pain can be indicative of many knee pathologies however it is imperative to ascertain the nature of its onset. Was it associated with trauma? Where is the pain and what is its character? Are there any specific aggravating or easing factors or can it follow a particular 24-hour pattern? Localising this pain can greatly aid in confirming your diagnosis. Specific knee questions (Table 1) can then be addressed in order to ensure accurate clinical assessment. Depending on the answers it may be prudent to ask clearing questions for the hip and lumbar spine to help with your differentials. It may also be appropriate to ask questions regarding systemic symptoms (e.g. night pain, fevers, weight loss). If your history can follow an organised pattern, it will be clear to the examiner that you have not only practiced but you are also knowledgeable in the field. While in clinical practice you will gain all the important information in a succinct and professional manner.
Michael Risebury
Abstract This article is intended as a guide to help improve and perfect your knee examination technique for the MRCS examination. The knee is a joint frequently assessed in the MRCS OSCE, due to the presence of reliable clinical signs in the chronic patient, who can easily attend for repeated examinations. The article will guide the reader through important aspects of the history and physical examination and how these can inform the clinical reasoning process and subsequent diagnosis and management.
Keywords Arthritis; fracture; knee; meniscus; patella
Introduction The knee is the largest synovial joint and comprises three articulations; the medial and lateral tibiofemoral and the patellofemoral compartments. These work together with a significant system of intra- and extra-articular ligaments, which provide stability. In addition, dense fibrous menisci are present between the medial and lateral tibiofemoral articulations to help reduce contact loading between the tibia and femur. In addition to the aforementioned structures, other pain producing structures around the knee consist of several bursae and the surrounding musculature. The approach to knee examination follows the usual orthopaedic mantra of ‘look, feel, move’, followed by special tests, however due to the complexity of the joint and its many sources of pathology, sound clinical examination followed by logical diagnostic reasoning is required for accurate diagnosis. With regard to the MRCS OSCE (and clinical practice), if you are clear why you need to complete a movement/test and how this will alter your clinical reasoning, you will appear more competent and thus your patient (and examiner!) will have more confidence in your ability. Rote learning a technique, just to pass an exam can lead to omitting important steps of the clinical examination and impair reasoning, ultimately leading to poor
Examination With regard to both the MRCS OSCE and clinical practice it is important that you introduce yourself to the patient and ask them their name, wash your hands and explain the steps of your examination. Failure to complete these small yet essential steps could preclude you from scoring full marks in the OSCE, whilst this is vital in clinical practice in order to establish a rapport with the patient. Before starting your examination ask if the patient is in any pain at rest, furthermore try to keep a view of the patient when completing any potentially pain provocative tests. Minimising position changes for the patient will make you appear well practiced in the OCSE and also minimise wasted time. Look Observation skills can give you a multitude of information before you touch the patient. You must ensure the patient is adequately exposed whilst maintaining their dignity at all times. With the patient in shorts it is then appropriate to inspect the lower limbs from an anterior, posterior and lateral viewpoint. Swelling, erythema, bruising, scars and any other skin changes should be carefully assessed. Does the knee appear to be in a neutral or in a varus (bowlegged) or valgus (knock-kneed) position? Are both knees symmetrical or is muscle wasting present? It would now be appropriate to observe the patient’s gait, assessing for any diminished weightbearing through either side, leading to an antalgic gait. Can the patent achieve full extension of the knee when standing? An inability here could be secondary to a fixed flexion deformity present in significant osteoarthritis if the history fits.
Daniel Blyth BSc(Hons) MBChB MRCS(Eng) is a CT2 at Hampshire Hospitals Foundation Trust, Basingstoke and North Hampshire Hospital, Basingstoke, UK. Conflicts of interest: none declared. Aadil Mumith BSc(Hons) MBBS PhD FRCS(Tr&Orth) is a Specialist Registrar ST8 in Trauma and Orthopaedics at Basingstoke and North Hampshire Hospital, Basingstoke, UK. Conflicts of interest: none declared. Michael Risebury MBBS MA FRCS(Tr&Orth) is a Consultant Trauma and Orthopaedic Surgeon at Basingstoke and North Hampshire Hospital, Basingstoke, UK. Conflicts of interest: none declared.
SURGERY xxx:xxx
1
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Blyth D et al., Examination of the knee for MRCS OSCE, Surgery, https://doi.org/10.1016/j.mpsur.2019.12.011
ORTHOPAEDICS e IV: LOWER LIMB
patient’s history as tenderness over the medial collateral ligament insertion could be mistaken for joint line tenderness (tip: feel with a single digit, this allows appropriate localisation of the pain). Be systematic when palpating to ensure most structures are assessed. Medial- MCL insertion on femur/tibia, medial joint line Midline-quadricep tendon, patella, patella tendon, tibial tuberosity Lateral-lateral joint line, LCL insertion on femur/fibula head Finally feel pulses in the foot and sensation of the lower leg, as these can be affected if neurovascular structures (popliteal artery/tibial nerve/common peroneal nerve) are damaged from injury or previous surgery.
Typical knee symptoms and associated problems Question
Possible pathology
Stiffness
C C C
Swelling - acute/immediately post injury
C C C C C
C C C
Swelling - gradual onset/chronic
C C
Swelling - specific location
C C C
Giving Way
C C C C C
Locking
C C
Osteoarthritis Rheumatoid arthritis Inflammatory arthropathy ACL rupture PCL rupture Meniscal lesion Fracture* Patella/quadriceps tendon Rupture* Synovitis Septic arthritis* Haemarthrosis* Osteoarthritis Rheumatoid arthritis Prepatellar Bursitis Infrapatellar bursitis Meniscal cyst Muscle weakness Muscle pain inhibition Extensor mechanism failure ACL/PCL/MCL/LCL/PLC injury Patella dislocation (recurrentchronic) Meniscal tear Loose intra-articular body
Move This is most easily completed with the patent still in a supine position. Hold the heels of both feet, lift up gently to assess for passive extension or hyperextension (Figure 1). A straight leg is by convention defined as 0 , with normal flexion up to a maximum of 120e140 depending on body habitus. Any degrees of hyperextension is denoted a negative angle. For each knee in turn, ask the patient to hold their knee fully straight and this allows the assessment of active extension. Some patients normally hyperextend, if this is asymmetrical passively it may suggest ligamentous injury. Starting with the patient’s normal knee ask them to flex the knee as much as possible which allows assessment of active flexion. By gently pushing the knee into further flexion assesses passive flexion. All movements should be assessed whilst watching the patient, as they could be in pain. Findings in the symptomatic knee are always compared to the asymptomatic side and if any limitations are observed, these must be quantified. For instance, a knee with fixed flexion deformity of 10 and flexion to 100 degrees is reported as ‘flexion from 10 to 100 ’. The ability to produce a straight leg raise can be assessed here both as a test for hip flexor and knee extensor strength, but also as a functional test for the integrity of the extensor mechanism of the knee, as this would delineate the presence of a patella/ quadricep tendon rupture or a locked knee, commonly due to a meniscal tear.
*these clinical scenarios will not appear in the OSCE as these are acute problems requiring urgent orthopaedic attention. ACL; anterior cruciate ligament, PCL; posterior cruciate ligament, MCL; medial collateral ligament, LCL; lateral collateral ligament, PLC; posterolateral corner
Table 1
All information is part of an evolving puzzle and is essential to complete a thorough diagnostic process. In the OSCE you must be attentive (and demonstrative) when looking for previous arthroscopy or total knee replacement scars. As you have now completed all the aspects of the examination which take place in standing the patient can move to the examination couch.
Special tests Many special tests of the knee exist with varying sensitivity and specificity. We will review the tests needed for a comprehensive examination of the knee and a clear pass at MRCS OSCE level. Be aware that you must compare findings of the symptomatic knee with the asymptomatic knee in order to detect subtle differences.
Feel In order to complete the next stages of your examination ask the patient to lie in a supine position on the couch with the knee flexed to 70 e90 . Start with palpation of the skin to feel for temperature differences, prior to palpating bony landmarks for tenderness. The knee is mostly subcutaneous apart from the posterior aspect, thus enabling easy palpation of the bony prominences and joint line. The quadricep and patella tendon should also be palpated along with the site of the medial and lateral collateral ligaments. The anatomical site of tenderness is usually a good indicator of the pathology. Depending on the history of the patient, significant joint line tenderness could be indicative of a meniscal lesion. Careful palpation is required in correlation with the
SURGERY xxx:xxx
Effusion tests Patella tap: this is best utilised in moderate effusions. The suprapatellar pouch is compressed with the hand moving all fluid into the joint. The right hand presses the patella posteriorly into the femoral trochlea. With a moderate effusion the patella will be felt striking the femur and bouncing off again. Patella sweep/wipe test: this is best utilised to assess for small effusions. The suprapatellar pouch is again emptied and occluded with your hand. Next, your other hand sweeps fluid
2
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Blyth D et al., Examination of the knee for MRCS OSCE, Surgery, https://doi.org/10.1016/j.mpsur.2019.12.011
ORTHOPAEDICS e IV: LOWER LIMB
thumb lying on the tibial tuberosity. The knee is then passively flexed to 20 and anterior translation of the tibia on the femur is attempted. This can be difficult in larger knees but it is the most reliable test for ACL deficiency. Voicing the presence or absence of an end point will prove your knowledge to the examiner and more than about 2 mm of excess anterior translation in the symptomatic knee compared to the asymptomatic side would indicate an ACL injury. Pivot shift (ACL): if an ACL injury is suspected this test must be performed to assess rotational stability in comparison to anteroposterior instability, with the anterior drawer and Lachman tests. Usually in the MRCS examination environment it is merely mentioned, as its can be uncomfortable for the patient. This test can be difficult as relaxation is required from the patient to allow thorough examination. It is particularly useful when examining a knee under anaesthetic and consists of axial load and valgus force applied during knee flexion from an extended position. Place the knee in extension and fix the lower leg between your nearside arm and chest. With your cephalad hand place an internal rotation force on the tibia and start to flex the knee, if positive at 20 of flexion a clear translation of the tibia will be seen and felt by the examiner. Posterior draw test (PCL): this test is performed in conjunction with the anterior drawer test. Positioning is the same, however a posterior force is applied to the tibial tuberosity to test for PCL laxity.
Figure 1 Examination under anaesthetic showing hyperextension of the knee. Note: The foot is not to be lifted this high during routine examination.
Valgus stress test (MCL): the aim is to stress the MCL. The femur is stabilised by placing your cephalad hand laterally on the thigh of the leg closest and gently push. Your caudad hand can then produce a valgus force at the knee by grasping the tibia or ankle and pulling it towards yourself at the same time. The amount of joint opening/laxity should be felt and observed and the presence or not of an end point. When performing this with the knee in 20 of flexion it examines the MCL in isolation. Laxity and absence of an end point in full extension would indicate more significant disruption, including damage to the cruciates, medial capsule, medial patella retinaculum which also act as stabilisers against valgus stress.
from the medial side and then compresses the lateral aspect of the joint. In a positive test the appearance of a ripple on the medial side confirms the presence of an effusion. Ligament testing Posterior sag (PCL): with the knee flexed to 90 and the ankles together the shape of the knee can be observed. When reviewing the knee from a lateral position, when positive, the tibia will appear to sag back in comparison to the end of the femur (Figure 2). Comparison to the uninjured side is always required. Anterior drawer test (ACL): here the knee is flexed to 90 and the foot is fixed by gently sitting on the foot. Hold the proximal tibia with fingers behind the knee and thumbs on either side of the tibial tuberosity. Forward traction of the tibia is performed. Here it is imperative to ensure the hamstrings are relaxed as they can halt the anterior translation of the tibia on the femur (Tip: push the hamstring tendons up with the top edge of your index fingers to prevent fighting against the hamstrings when pulling the tibia forward). This should be performed after observing the tibia laterally in 90 of flexion. If the tibia is resting in a posterior sag position excessive forward translation would appear as a positive anterior drawer test and thus incorrectly indicative of an ACL injury. In this case the PCL is deficient. Awareness of this possible false positive will show an elevated knowledge in your exam.
Varus stress test (LCL): here the aim is to stress the LCL with a varus force. The method is as for the valgus stress test except the thigh is stabilised medially and your caudad hand produces a varus force on the knee by pushing the tibia or ankle away. This is a rare isolated injury and the lateral structures can be naturally laxer. It is important as with all the above tests to compare to the uninjured side. Dial test (posterolateral corner): PLC injuries are more commonly associated in the presence of an ACL/PCL injury. The key to examination here is eliciting increased external rotation in comparison to the uninjured side of the knee. Position the patient prone (lying on their front) and flex both knees to 30 . Grasp the patient’s ankles and with their knees together passively produce external rotation at the knee (toes point away from each other). Both sides should be compared and this is to be repeated at 90 flexion. Rare isolated PLC injury will show increased external
Lachman test (ACL): grasp the distal femur with your cephalad hand and the proximal tibia with you caudad hand, with your
SURGERY xxx:xxx
3
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Blyth D et al., Examination of the knee for MRCS OSCE, Surgery, https://doi.org/10.1016/j.mpsur.2019.12.011
ORTHOPAEDICS e IV: LOWER LIMB
McMurray’s test: this can be painful for the patient and thus they should be warned prior to your examination. It is intended to trap the meniscal lesion between articular surfaces, an audible/ palpable click or snap will be apparent in a positive test. Place one hand on the patient’s knee with your thumb and fingers palpating the joint line. The other hand will grasp the heel and fully flex the knee. Next the lower leg is internally rotated and the knee slowly extended with a varus force applied to the knee testing the lateral compartment. The same method is applied only with external rotation of the tibia and extension whilst under valgus force, testing the medial compartment. It is important to remember that a negative test does not rule out a meniscal lesion and further Magnetic Resonance Imaging (MRI) may be appropriate. Patellofemoral pain testing Clarke’s test: this would be positive in pathologies such as chondromalacia and patellofemoral arthritis. Gentle pressure is applied to the superior pole of the patella and pushed down onto the trochlea. The patient is asked to contract the quadriceps and pain is a positive result. Patellar glide test: assessment for patella subluxation/instability is performed supine with the knee flexed to 20 and relaxed. The patella should be able to glide a quarter of its width medially and half its width laterally. Any further displacement laterally may be indicative of recurrent dislocations of the patella and medial retinaculum damage. Patella apprehension test: this investigates the presence of previous subluxation/dislocation of the patella. As described in the Patella Glide Test, when applying a lateral force to the patella the patient’s knee is passively flexed. The patient’s face is observed for any apprehension to the movement. Having completed your examination, it is polite to thank the patient for their time. It is worth communicating to your examiner that you would assess the joint above and below for completeness and order any appropriate investigations. In this situation this may be an AP and lateral radiograph of the knee or an MRI scan.
Figure 2 (a) A positive posterior sag test at rest. (b) Bringing the knee back to ‘neutral’ with anterior translation of the tibia relative to the femur. If there was further translation past the ‘neutral’, only then would it be a positive anterior drawer test. Examination of the ‘normal’ side would help in defining where neutral is.
Conclusion
rotation at 30 on the injured side but not at 90 . When in conjunction with a combined PCL & PLC injury increased external rotation will be evidence at both 90 and 30 of knee flexion.
The knee is a frequently assessed joint in the MRCS OSCE examination. You should be comfortable taking a detailed history and thorough examination of the joint prior to your examination. Practice with colleagues at mastering the handling of specific tests can take time and, if done well, will improve your proficiency.
Meniscal testing Meniscal provocation tests can be uncomfortable and therefore during the OSCE are not expected to be completed. Knowledge and practice are still required on the chance you may be asked to describe or demonstrate the test.
Summary/MRCS OSCE proforma 1. 2. 3. 4. 5. 6.
Introduce yourself History Wash hands/alcohol gel Stand the patient and observe Gait analysis Supine: Observe, palpate and active/passive/resisted movements 7. Patella tap and sweep tests, varus and valgus stress tests
Apley’s grind test: position the patient prone and flex the knee to 90 . Here a longitudinal force is placed through the lower leg and into the knee with the aim of forcing the tibiofemoral surfaces together. When the foot is then rotated into internal and external rotation the meniscal lesion will be caught by the compression and pain will be produced.
SURGERY xxx:xxx
4
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Blyth D et al., Examination of the knee for MRCS OSCE, Surgery, https://doi.org/10.1016/j.mpsur.2019.12.011
ORTHOPAEDICS e IV: LOWER LIMB
8. Flex knee to 90 : posterior sag, anterior drawer, posterior drawer, McMurray’s test, Lachman’s test 9. Patella glide and apprehension tests, Clarke’s test. 10. Turn prone: dial test 11. Describe meniscal or pivot shift tests 12. Thank patient, communicate with examiner and wash hands/alcohol gel. A
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FURTHER READING Harris N, Ali F. Examination techniques in orthopaedics. Cambridge University Press. Solomon L et al. Apley and solomon’s concise system of orthopaedics and trauma. CRC Press. McRae, R. Clinical orthopaedic examination. Churchill Livingstone Elsevier Press.
5
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Blyth D et al., Examination of the knee for MRCS OSCE, Surgery, https://doi.org/10.1016/j.mpsur.2019.12.011
Examination of the knee for MRCS OSCE
outcomes for the patient and your exam mark. Sound knowledge of anatomy is essential but this is beyond the scope of this article, the authors recommend thoroughly revising knee anatomy prior to learning the clinical examination.
Daniel Blyth
History
Aadil Mumith
All clinical examinations should start with a thorough history of the presenting complaint. Once you are aware how and when the problem started you can tailor your history and physical examination to the patient. The presence of pain can be indicative of many knee pathologies however it is imperative to ascertain the nature of its onset. Was it associated with trauma? Where is the pain and what is its character? Are there any specific aggravating or easing factors or can it follow a particular 24-hour pattern? Localising this pain can greatly aid in confirming your diagnosis. Specific knee questions (Table 1) can then be addressed in order to ensure accurate clinical assessment. Depending on the answers it may be prudent to ask clearing questions for the hip and lumbar spine to help with your differentials. It may also be appropriate to ask questions regarding systemic symptoms (e.g. night pain, fevers, weight loss). If your history can follow an organised pattern, it will be clear to the examiner that you have not only practiced but you are also knowledgeable in the field. While in clinical practice you will gain all the important information in a succinct and professional manner.
Michael Risebury
Abstract This article is intended as a guide to help improve and perfect your knee examination technique for the MRCS examination. The knee is a joint frequently assessed in the MRCS OSCE, due to the presence of reliable clinical signs in the chronic patient, who can easily attend for repeated examinations. The article will guide the reader through important aspects of the history and physical examination and how these can inform the clinical reasoning process and subsequent diagnosis and management.
Keywords Arthritis; fracture; knee; meniscus; patella
Introduction The knee is the largest synovial joint and comprises three articulations; the medial and lateral tibiofemoral and the patellofemoral compartments. These work together with a significant system of intra- and extra-articular ligaments, which provide stability. In addition, dense fibrous menisci are present between the medial and lateral tibiofemoral articulations to help reduce contact loading between the tibia and femur. In addition to the aforementioned structures, other pain producing structures around the knee consist of several bursae and the surrounding musculature. The approach to knee examination follows the usual orthopaedic mantra of ‘look, feel, move’, followed by special tests, however due to the complexity of the joint and its many sources of pathology, sound clinical examination followed by logical diagnostic reasoning is required for accurate diagnosis. With regard to the MRCS OSCE (and clinical practice), if you are clear why you need to complete a movement/test and how this will alter your clinical reasoning, you will appear more competent and thus your patient (and examiner!) will have more confidence in your ability. Rote learning a technique, just to pass an exam can lead to omitting important steps of the clinical examination and impair reasoning, ultimately leading to poor
Examination With regard to both the MRCS OSCE and clinical practice it is important that you introduce yourself to the patient and ask them their name, wash your hands and explain the steps of your examination. Failure to complete these small yet essential steps could preclude you from scoring full marks in the OSCE, whilst this is vital in clinical practice in order to establish a rapport with the patient. Before starting your examination ask if the patient is in any pain at rest, furthermore try to keep a view of the patient when completing any potentially pain provocative tests. Minimising position changes for the patient will make you appear well practiced in the OCSE and also minimise wasted time. Look Observation skills can give you a multitude of information before you touch the patient. You must ensure the patient is adequately exposed whilst maintaining their dignity at all times. With the patient in shorts it is then appropriate to inspect the lower limbs from an anterior, posterior and lateral viewpoint. Swelling, erythema, bruising, scars and any other skin changes should be carefully assessed. Does the knee appear to be in a neutral or in a varus (bowlegged) or valgus (knock-kneed) position? Are both knees symmetrical or is muscle wasting present? It would now be appropriate to observe the patient’s gait, assessing for any diminished weightbearing through either side, leading to an antalgic gait. Can the patent achieve full extension of the knee when standing? An inability here could be secondary to a fixed flexion deformity present in significant osteoarthritis if the history fits.
Daniel Blyth BSc(Hons) MBChB MRCS(Eng) is a CT2 at Hampshire Hospitals Foundation Trust, Basingstoke and North Hampshire Hospital, Basingstoke, UK. Conflicts of interest: none declared. Aadil Mumith BSc(Hons) MBBS PhD FRCS(Tr&Orth) is a Specialist Registrar ST8 in Trauma and Orthopaedics at Basingstoke and North Hampshire Hospital, Basingstoke, UK. Conflicts of interest: none declared. Michael Risebury MBBS MA FRCS(Tr&Orth) is a Consultant Trauma and Orthopaedic Surgeon at Basingstoke and North Hampshire Hospital, Basingstoke, UK. Conflicts of interest: none declared.
SURGERY xxx:xxx
1
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Blyth D et al., Examination of the knee for MRCS OSCE, Surgery, https://doi.org/10.1016/j.mpsur.2019.12.011
ORTHOPAEDICS e IV: LOWER LIMB
patient’s history as tenderness over the medial collateral ligament insertion could be mistaken for joint line tenderness (tip: feel with a single digit, this allows appropriate localisation of the pain). Be systematic when palpating to ensure most structures are assessed. Medial- MCL insertion on femur/tibia, medial joint line Midline-quadricep tendon, patella, patella tendon, tibial tuberosity Lateral-lateral joint line, LCL insertion on femur/fibula head Finally feel pulses in the foot and sensation of the lower leg, as these can be affected if neurovascular structures (popliteal artery/tibial nerve/common peroneal nerve) are damaged from injury or previous surgery.
Typical knee symptoms and associated problems Question
Possible pathology
Stiffness
C C C
Swelling - acute/immediately post injury
C C C C C
C C C
Swelling - gradual onset/chronic
C C
Swelling - specific location
C C C
Giving Way
C C C C C
Locking
C C
Osteoarthritis Rheumatoid arthritis Inflammatory arthropathy ACL rupture PCL rupture Meniscal lesion Fracture* Patella/quadriceps tendon Rupture* Synovitis Septic arthritis* Haemarthrosis* Osteoarthritis Rheumatoid arthritis Prepatellar Bursitis Infrapatellar bursitis Meniscal cyst Muscle weakness Muscle pain inhibition Extensor mechanism failure ACL/PCL/MCL/LCL/PLC injury Patella dislocation (recurrentchronic) Meniscal tear Loose intra-articular body
Move This is most easily completed with the patent still in a supine position. Hold the heels of both feet, lift up gently to assess for passive extension or hyperextension (Figure 1). A straight leg is by convention defined as 0 , with normal flexion up to a maximum of 120e140 depending on body habitus. Any degrees of hyperextension is denoted a negative angle. For each knee in turn, ask the patient to hold their knee fully straight and this allows the assessment of active extension. Some patients normally hyperextend, if this is asymmetrical passively it may suggest ligamentous injury. Starting with the patient’s normal knee ask them to flex the knee as much as possible which allows assessment of active flexion. By gently pushing the knee into further flexion assesses passive flexion. All movements should be assessed whilst watching the patient, as they could be in pain. Findings in the symptomatic knee are always compared to the asymptomatic side and if any limitations are observed, these must be quantified. For instance, a knee with fixed flexion deformity of 10 and flexion to 100 degrees is reported as ‘flexion from 10 to 100 ’. The ability to produce a straight leg raise can be assessed here both as a test for hip flexor and knee extensor strength, but also as a functional test for the integrity of the extensor mechanism of the knee, as this would delineate the presence of a patella/ quadricep tendon rupture or a locked knee, commonly due to a meniscal tear.
*these clinical scenarios will not appear in the OSCE as these are acute problems requiring urgent orthopaedic attention. ACL; anterior cruciate ligament, PCL; posterior cruciate ligament, MCL; medial collateral ligament, LCL; lateral collateral ligament, PLC; posterolateral corner
Table 1
All information is part of an evolving puzzle and is essential to complete a thorough diagnostic process. In the OSCE you must be attentive (and demonstrative) when looking for previous arthroscopy or total knee replacement scars. As you have now completed all the aspects of the examination which take place in standing the patient can move to the examination couch.
Special tests Many special tests of the knee exist with varying sensitivity and specificity. We will review the tests needed for a comprehensive examination of the knee and a clear pass at MRCS OSCE level. Be aware that you must compare findings of the symptomatic knee with the asymptomatic knee in order to detect subtle differences.
Feel In order to complete the next stages of your examination ask the patient to lie in a supine position on the couch with the knee flexed to 70 e90 . Start with palpation of the skin to feel for temperature differences, prior to palpating bony landmarks for tenderness. The knee is mostly subcutaneous apart from the posterior aspect, thus enabling easy palpation of the bony prominences and joint line. The quadricep and patella tendon should also be palpated along with the site of the medial and lateral collateral ligaments. The anatomical site of tenderness is usually a good indicator of the pathology. Depending on the history of the patient, significant joint line tenderness could be indicative of a meniscal lesion. Careful palpation is required in correlation with the
SURGERY xxx:xxx
Effusion tests Patella tap: this is best utilised in moderate effusions. The suprapatellar pouch is compressed with the hand moving all fluid into the joint. The right hand presses the patella posteriorly into the femoral trochlea. With a moderate effusion the patella will be felt striking the femur and bouncing off again. Patella sweep/wipe test: this is best utilised to assess for small effusions. The suprapatellar pouch is again emptied and occluded with your hand. Next, your other hand sweeps fluid
2
Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Blyth D et al., Examination of the knee for MRCS OSCE, Surgery, https://doi.org/10.1016/j.mpsur.2019.12.011
ORTHOPAEDICS e IV: LOWER LIMB
thumb lying on the tibial tuberosity. The knee is then passively flexed to 20 and anterior translation of the tibia on the femur is attempted. This can be difficult in larger knees but it is the most reliable test for ACL deficiency. Voicing the presence or absence of an end point will prove your knowledge to the examiner and more than about 2 mm of excess anterior translation in the symptomatic knee compared to the asymptomatic side would indicate an ACL injury. Pivot shift (ACL): if an ACL injury is suspected this test must be performed to assess rotational stability in comparison to anteroposterior instability, with the anterior drawer and Lachman tests. Usually in the MRCS examination environment it is merely mentioned, as its can be uncomfortable for the patient. This test can be difficult as relaxation is required from the patient to allow thorough examination. It is particularly useful when examining a knee under anaesthetic and consists of axial load and valgus force applied during knee flexion from an extended position. Place the knee in extension and fix the lower leg between your nearside arm and chest. With your cephalad hand place an internal rotation force on the tibia and start to flex the knee, if positive at 20 of flexion a clear translation of the tibia will be seen and felt by the examiner. Posterior draw test (PCL): this test is performed in conjunction with the anterior drawer test. Positioning is the same, however a posterior force is applied to the tibial tuberosity to test for PCL laxity.
Figure 1 Examination under anaesthetic showing hyperextension of the knee. Note: The foot is not to be lifted this high during routine examination.
Valgus stress test (MCL): the aim is to stress the MCL. The femur is stabilised by placing your cephalad hand laterally on the thigh of the leg closest and gently push. Your caudad hand can then produce a valgus force at the knee by grasping the tibia or ankle and pulling it towards yourself at the same time. The amount of joint opening/laxity should be felt and observed and the presence or not of an end point. When performing this with the knee in 20 of flexion it examines the MCL in isolation. Laxity and absence of an end point in full extension would indicate more significant disruption, including damage to the cruciates, medial capsule, medial patella retinaculum which also act as stabilisers against valgus stress.
from the medial side and then compresses the lateral aspect of the joint. In a positive test the appearance of a ripple on the medial side confirms the presence of an effusion. Ligament testing Posterior sag (PCL): with the knee flexed to 90 and the ankles together the shape of the knee can be observed. When reviewing the knee from a lateral position, when positive, the tibia will appear to sag back in comparison to the end of the femur (Figure 2). Comparison to the uninjured side is always required. Anterior drawer test (ACL): here the knee is flexed to 90 and the foot is fixed by gently sitting on the foot. Hold the proximal tibia with fingers behind the knee and thumbs on either side of the tibial tuberosity. Forward traction of the tibia is performed. Here it is imperative to ensure the hamstrings are relaxed as they can halt the anterior translation of the tibia on the femur (Tip: push the hamstring tendons up with the top edge of your index fingers to prevent fighting against the hamstrings when pulling the tibia forward). This should be performed after observing the tibia laterally in 90 of flexion. If the tibia is resting in a posterior sag position excessive forward translation would appear as a positive anterior drawer test and thus incorrectly indicative of an ACL injury. In this case the PCL is deficient. Awareness of this possible false positive will show an elevated knowledge in your exam.
Varus stress test (LCL): here the aim is to stress the LCL with a varus force. The method is as for the valgus stress test except the thigh is stabilised medially and your caudad hand produces a varus force on the knee by pushing the tibia or ankle away. This is a rare isolated injury and the lateral structures can be naturally laxer. It is important as with all the above tests to compare to the uninjured side. Dial test (posterolateral corner): PLC injuries are more commonly associated in the presence of an ACL/PCL injury. The key to examination here is eliciting increased external rotation in comparison to the uninjured side of the knee. Position the patient prone (lying on their front) and flex both knees to 30 . Grasp the patient’s ankles and with their knees together passively produce external rotation at the knee (toes point away from each other). Both sides should be compared and this is to be repeated at 90 flexion. Rare isolated PLC injury will show increased external
Lachman test (ACL): grasp the distal femur with your cephalad hand and the proximal tibia with you caudad hand, with your
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ORTHOPAEDICS e IV: LOWER LIMB
McMurray’s test: this can be painful for the patient and thus they should be warned prior to your examination. It is intended to trap the meniscal lesion between articular surfaces, an audible/ palpable click or snap will be apparent in a positive test. Place one hand on the patient’s knee with your thumb and fingers palpating the joint line. The other hand will grasp the heel and fully flex the knee. Next the lower leg is internally rotated and the knee slowly extended with a varus force applied to the knee testing the lateral compartment. The same method is applied only with external rotation of the tibia and extension whilst under valgus force, testing the medial compartment. It is important to remember that a negative test does not rule out a meniscal lesion and further Magnetic Resonance Imaging (MRI) may be appropriate. Patellofemoral pain testing Clarke’s test: this would be positive in pathologies such as chondromalacia and patellofemoral arthritis. Gentle pressure is applied to the superior pole of the patella and pushed down onto the trochlea. The patient is asked to contract the quadriceps and pain is a positive result. Patellar glide test: assessment for patella subluxation/instability is performed supine with the knee flexed to 20 and relaxed. The patella should be able to glide a quarter of its width medially and half its width laterally. Any further displacement laterally may be indicative of recurrent dislocations of the patella and medial retinaculum damage. Patella apprehension test: this investigates the presence of previous subluxation/dislocation of the patella. As described in the Patella Glide Test, when applying a lateral force to the patella the patient’s knee is passively flexed. The patient’s face is observed for any apprehension to the movement. Having completed your examination, it is polite to thank the patient for their time. It is worth communicating to your examiner that you would assess the joint above and below for completeness and order any appropriate investigations. In this situation this may be an AP and lateral radiograph of the knee or an MRI scan.
Figure 2 (a) A positive posterior sag test at rest. (b) Bringing the knee back to ‘neutral’ with anterior translation of the tibia relative to the femur. If there was further translation past the ‘neutral’, only then would it be a positive anterior drawer test. Examination of the ‘normal’ side would help in defining where neutral is.
Conclusion
rotation at 30 on the injured side but not at 90 . When in conjunction with a combined PCL & PLC injury increased external rotation will be evidence at both 90 and 30 of knee flexion.
The knee is a frequently assessed joint in the MRCS OSCE examination. You should be comfortable taking a detailed history and thorough examination of the joint prior to your examination. Practice with colleagues at mastering the handling of specific tests can take time and, if done well, will improve your proficiency.
Meniscal testing Meniscal provocation tests can be uncomfortable and therefore during the OSCE are not expected to be completed. Knowledge and practice are still required on the chance you may be asked to describe or demonstrate the test.
Summary/MRCS OSCE proforma 1. 2. 3. 4. 5. 6.
Introduce yourself History Wash hands/alcohol gel Stand the patient and observe Gait analysis Supine: Observe, palpate and active/passive/resisted movements 7. Patella tap and sweep tests, varus and valgus stress tests
Apley’s grind test: position the patient prone and flex the knee to 90 . Here a longitudinal force is placed through the lower leg and into the knee with the aim of forcing the tibiofemoral surfaces together. When the foot is then rotated into internal and external rotation the meniscal lesion will be caught by the compression and pain will be produced.
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ORTHOPAEDICS e IV: LOWER LIMB
8. Flex knee to 90 : posterior sag, anterior drawer, posterior drawer, McMurray’s test, Lachman’s test 9. Patella glide and apprehension tests, Clarke’s test. 10. Turn prone: dial test 11. Describe meniscal or pivot shift tests 12. Thank patient, communicate with examiner and wash hands/alcohol gel. A
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FURTHER READING Harris N, Ali F. Examination techniques in orthopaedics. Cambridge University Press. Solomon L et al. Apley and solomon’s concise system of orthopaedics and trauma. CRC Press. McRae, R. Clinical orthopaedic examination. Churchill Livingstone Elsevier Press.
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Ó 2019 Published by Elsevier Ltd.
Please cite this article as: Blyth D et al., Examination of the knee for MRCS OSCE, Surgery, https://doi.org/10.1016/j.mpsur.2019.12.011