This post has excerpts from Episode #98 Knee Pain: History, exam, bracing, x-rays, and injectables [Link is to the show notes and podcast] from the Curbsiders Internal Medicine Podcast.
In addition, I have linked to the tables from the American College of Radiology Appropriateness Criteria for Chronic Knee Pain [Link is to the PDF of Narrative and Rating Table].
Next I’ve included links to the article Arthroscopic surgery for degenerative knee arthritis and meniscal tears: a clinical practice guideline [PubMed Abstract] [Full Text HTML] [Full Text PDF]. BMJ. 2017 May 10;357:j1982. doi: 10.1136/bmj.j1982.
WHAT YOU NEED TO KNOW [from the above article]
• We make a strong recommendation against the use of arthroscopy in nearly all patients with degenerative knee disease, based on linked systematic reviews; further research is
unlikely to alter this recommendation
• This recommendation applies to patients with or without imaging evidence of osteoarthritis, mechanical symptoms, or
sudden symptom onset
• Healthcare administrators and funders may use the number of arthroscopies performed in patients with degenerative knee disease as an indicator of quality care.
• Knee arthroscopy is the most common orthopaedic procedure in countries with available data
• This Rapid Recommendation package was triggered by a randomised controlled trial published in The BMJ in June 2016
which found that, among patients with a degenerative medial meniscus tear, knee arthroscopy was no better than exercise
And because the vast majority of chronic knee pain is due to osteoarthritis I’ve included a link to the National Institute For Health And Care Excellence (NICE) Osteoarthritis: care and management-Clinical guideline [CG177] Published date: February 2014:
This guideline includes recommendations on:
As Dr. Parks reminds us in the Curbsiders’ podcast, therapy for an exacerbation of chronic knee pain consists of non-pharmacologic management [and the NICE Osteoarthritis guideline reminds us to consider a TENS unit], NSAIDS, and steroid injection of the knee joint.*
* Here is a resource on how to perform joint injections: According to the reviews on Amazon, Injection Techniques in Musculoskeletal Medicine: A Practical Manual for Clinicians in Primary and Secondary Care 4th Edition is an excellent how-to manual. But there is a new 5th edition coming November 15, 2018 which will have a number of excellent upgrades including a website with an online trainer and access to over 50 instructional video clips – order the 5th edition.
And finally, because exercise is the recommended treatment for knee osteoarthritis, here is a link to the YouTube video, McKenzie Method to Treat Your Own Knee Pain (Exercises).
A great resource for patients with knee pain is Robin McKenzie’s book, Treat Your Own Knee.
So here are the excerpts from #98: Knee Pain: History, exam, bracing, x-rays, and injectables JUNE 4, 2018 By MATTHEW WATTO, MD:
- First, rule out emergencies e.g. septic arthritis–the knee will be red, swollen, tense, and “really uncomfortable”. The patient may not be able to bear any weight. Mechanism of injury also heightens urgency e.g. severe trauma. -Dr Parks
- History taking: chronicity (will push you more towards osteoarthritis), pain on descending the stairs (patellofemoral joint pain), swelling, mechanism of injury and whether pain is relieved with oral anti-inflammatory agents. Morning stiffness isn’t as useful. -Dr Parks expert opinion
- Ask about mechanical symptoms–locking, catching, instability–instability is a strong clue for ligament involvement. “Giving out”–Ask them to describe it in greater detail. Could have a number of causes: ligament injury, muscle weakness, reflex giving way due to pain in “sweet spot”. -Dr Parks
Next we want to fit the patient into one of five buckets that “will cover almost everything that comes into the orthopedics office”:
- Ligament injury: it requires a lot of violence/force to tear ligaments, which are wide as a pinky finger. Easy to detect with physical exam, and with a history of trauma. -Dr Parks
- Meniscus injury: a significant number, upwards of 50% of adults >60, have incidental meniscus tears identified on MRI. (Englund et al. Incidental Meniscal Findings on Knee MRI in Middle-Aged and Elderly Persons. N Engl J Med. 2008; 359:1108-1115). It is hard to know in a middle-aged/older person whether the meniscus tear is an incidental finding or is really causing the symptoms so the threshold for intervention is much higher. Conversely, a 33-year-old with a meniscus tear, might warrant an invasive orthopedic intervention. -Dr Parks
- Osteoarthritis: Chronic, bilateral, exacerbated by recent trauma or joint stressor.
- Patellofemoral joint issues: May overlap with arthritis. Conditions include: patellofemoral syndrome, chondromalacia, and other non-arthritic diagnoses. The typical pain is anterior, worse with descending stairs or prolonged sitting (Theater sign), and notable for crepitation under patella. -Dr Parks
- None of the above: Tendonitis (e.g. pes anserine, iliotibial band, patellar/quadriceps), or referred pain from the hip or spine (e.g. lumbosacral radiculopathy).
- X-rays (XR): Cheap, easy and available in many offices.
- Do NOT order the standard “knee series” or “three view series,” which consists of a non-weight bearing AP, lateral, and obliques. ED and urgent care provider’s like this series because it can rule out a fracture. -Dr Park
- The 4 proper XR views for knee osteoarthritis (see Practical Office Orthopedics for more detail):
- Standing AP: Cartilage is radiolucent (invisible on XR), so a clear space is visible on normal joint XR. In arthritis, the dark space narrows because cartilage is degraded or absent. Weight-bearing views allow better assessment of the true joint space and loss of cartilage.
- Merchant’s aka sunrise aka sub-patellar view (see two images below, provided by Dr. Parks):Shows whether the patella is centered above the femur, and whether there is healthy joint space present.
- Rosenberg’s view aka flexed knee/weight bearing: Identifies a subset of patients with arthritic wear on the posterior femur and all of tibia, but who have some cartilage anteriorly.
- Lateral: If you need to ditch a 4th view, ditch this one. Non-essential.
The Knee Exam Breakdown: This should take around 30 seconds to administer. See Dr. Parks’ video!
- Watch the patient walk. Look for a limp, and gait abnormalities.
- Look at the skin for scars, redness/swelling.
- Have the patient sit on the edge of exam table with knees bent. Put a hand on the kneecap, and flex and extend the knee. Crepitus may not be clinically consequential unless it’s worse on the side with pain or abnormal mobility. (And don’t bet your money on the value of Fine vs. Coarse distinctions).(Song et al. Noise around the knee. Clin Orthop Surg. 2018. 10(1):1-8.)
- Have the patient lie on their back in a supine position with legs extended and note whether their extension is full or limited.
- Bend their knee so their heel moves towards their bottom. This will tell you their flexion range of motion limit. If they have a meniscus tear, this flexion will recreate pinpoint pain and joint line tenderness on the side of the torn meniscus
- Next, while they’re in that position in flexion, put one hand on their foot, other hand on their knee, and rotate hip joint through full ROM to rule out hip disease.
- In the same position, with your hand on the patient’s knee, feel and press on joint line to check for joint line tenderness. Perform McMurray’s test for finding meniscus tears (See Dr. Parks’ video).
- Medial Collateral Ligament (MCL)/ Lateral Collateral Ligament (LCL): Put the knee in extension, hold the top segment (thigh) with one hand, put other hand down at ankle, and push the leg toward the midline or away from the midline. Stretching toward the midline will stretch the LCL, stretching away from the midline will stretch the MCL.
- N.b. there is tons of variability in how flexible individuals are, person to person, in this direction when uninjured. Test the uninjured knee and compare that side to the injured side since there is very little variability between sides: If there’s increased laxity, >3 mm in excess of the other side, that suggests pathology. (Phisitkul et al. MCL Injuries of the Knee: Current Concepts Review. Iowa Orthop J. 2006;26:77-90)
- Anterior Cruciate Ligament (ACL): the ACL exists to prevent the tibia from translating anteriorly in relation to the patella/femur.
- Lachman’s test [Link is to the YouTube video on how to perform the Lachman’s test] is better than the Drawer test, which can be confounded by the iliotibial (IT) band. Do an anterior pull, but with the knee at 30 degrees flexion. This is the position of maximal relaxation of the IT band and other secondary structures, so it will amplify the tibia’s anterior motion if patient lacks an intact ACL. (Koster et al. ACL Injury: how do the physical examination tests compare? J Fam Pract. 2018. 67(3):130-134.)
- Posterior collateral ligament, pathology is pretty rare, so we won’t discuss the ligament tests for that one in this quick knee exam.
Treatment of knee pain consists of nonpharmacologic treatment, NSAIDs, and corticosteroid knee injections.
Dr Parks’ Take Home Points
- When you see a patient with an orthopedic problem, first sort out the emergencies from the non-emergencies. Look for signs of infection, trauma, bleeding.
- If you aren’t an expert, have a low threshold for sending to an orthopedist or to the ED. If it doesn’t look right, trust your instincts and seek specialty evaluation.
- Using an algorithmic approach to knee complaints will allow for diagnosis of most knee complaints–using specific questions on history and a rigorous, targeted knee exam on physical.