Knee pain is easy with practical tips from Orthopedist, medical educator, car-builder, and inventor extraordinaire Dr. Ted Parks. He teaches us the four buckets of knee pain, how to perform a 30-second knee exam, choose a knee brace, order x-rays, and the red flags to look for in a history and physical that should have you shouting for your closest neighborhood orthopedic surgeon. This episode is brought to you in partnership with the American College of Physicians. ACP members can claim free CME-MOC credit at acponline.org/curbsiders.
Check out our video of the Parks-Approved 30-second knee exam!
- Written by: Nora Taranto BA, Matthew Watto MD
- Produced by: Chris Chiu MD and Nora Taranto BA
- Edited by: Matthew Watto MD.
- Hosts: Matthew Watto MD, Stuart Brigham MD, Paul Williams MD.
- Guest: Ted Parks MD.
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Clinical Pearls and In-Depth Show Notes
“To be successful in life, you need to have three bones: a wishbone, a backbone, and a funny bone.” -Ted Parks MD
Some Clinical Pearls about how to approach the patient with knee pain:
- 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
- Fit patient into one of four or five buckets, which 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). [Practical Office Orthopedics Chapter 1: The Knee: Other Conditions You Will Encounter (e-book available via access medicine, but subscription required)].
- 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 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.
Nonpharmacologic therapies: Patient education about knee osteoarthritis management and prognosis, weight loss of >7.5% if obese, exercise (activity as tolerated e.g. walking, tai chi, yoga, etc.) should always be part of management for knee osteoarthritis (LA Deveza and K Bennell. UpToDate 2018)
NSAIDS versus Corticosteroid injections
- Both may be considered 1st line. -Dr Parks’ expert opinion
- N.b., from Dr. Parks: Oral anti-inflammatories are often thought of as first line because they’re “conservative”, but at higher doses and frequencies, and if being used long-term–may be problematic due to gastrointestinal, renal and cardiac toxicity. (Pelletier et al. Efficacy and safety of oral NSAIDs and analgesics in the management of osteoarthritis: Evidence from real-life setting trials and surveys. Semin Arthritis Rheum. 2016; 45(4 suppl):S22-7.)
- Perhaps a better option: the corticosteroid injection
Newer/More Questionable Therapies
- Platelet Rich Plasma (PRP) injections: Platelets aggregate, and release chemical signals that promote healing. Hypothetically, injecting these into the joint space might promote healing. No studies have yet shown healing/improvement with PRP injections. PRP does NOT have FDA approval, and remains uninsured/out-of-pocket. But there are several studies showing increased patient satisfaction. (Meheux et al. Efficacy of Intra-articular Platelet-Rich Plasma Injections of Knee Osteoarthritis: A systematic Review. Arthroscopy. 2016;32(3):495.) Per Dr. Parks: there’s a lot we don’t know about this yet. Evidence will continue to pan out. He’s a skeptic as of yet, but evidence may pan out.
- Stem cell Injection: Stem cells can differentiate into any tissue type we can imagine and likely have the potential to cure many different conditions. Perhaps stem cells could repopulate the area that has been lost or worn away in osteoarthritis. But at the moment, though we can make chondroblasts from stem cells and can make chondroblasts produce cartilage in vitro, it has not been effectively used in targeting only those areas worn away. “We need stem cells that parachute inside the joint space and find the right spots. We need them and their products to irreversibly bind to the bone once they’ve landed.”–Dr. Parks. Studies have shown safety and subjective satisfaction, but they haven’t yet shown fixed anatomy or growth of cartilage in the right spots (Jo CH et al. Am J Sports Med. 2017. PMID: 28746812).
- Hyaluronic acid/Hyaluronate: Call it hyaluronate because patients don’t like the “acid” part. It is a component of articular cartilage, and the theory is that perhaps by injecting it, the cartilage will grow back. Studies have shown this doesn’t happen, but a proportion of patients who received these injections felt symptomatic relief. It has FDA approval for knee osteoarthritis, but it is expensive, and evidence for efficacy is only marginal. In Dr. Parks’ expert opinion: never choose it as a first line therapy for osteoarthritis. (McAlindon et al. OARSI guidelines for the non-surgical management of knee osteoarthritis. Osteoarthritis Cartilage. 2014;22(3):363-88.)
- Glucosamine chondroitin Oral supplements: Essentially, you eat the chemical components of cartilage and somehow they magically end up in the knee in the right spot. Several studies showing subjective satisfaction, but not much else. (Eriksen et al. Risk of bias and brand explain the observed inconsistency in trials on glucosamine for symptomatic relief of osteoarthritis: a meta-analysis of placebo-controlled trials. Arthritis Care Res. 2014; 66(12):1844-55.) Note: An industry sponsored study of chondroitin sulfate found it superior to placebo and noninferior to celecoxib for knee OA (Reginster JY et al. Ann Rheum Dis 2017 PMID: 28533290)
- Miscellaneous treatment options, per Dr. Parks: Not as big a fan of lidocaine patches because the data about measuring how much gets into the knee itself is pretty small (and it’s a ton of paperwork to get them approved). Try everything you can that’s safe, orthodox and unorthodox, and he’ll likely maintain an open mind. If still not ok, then he’s got the nuclear option (knee replacement surgery).
Bracing Options: Not great for osteoarthritis
- Hinged braces: these are really for ligament injuries where they help to stabilize the knee laterally. Not as useful for patients with osteoarthritis. –Dr Parks’ expert opinion
- For osteoarthritis there are two bracing options, neither of which works well: 1) the unloader brace– pushes knee to medial or lateral side, but expensive and uncomfortable. 2) the sleeve brace– cheap and keeps the knee warm. –Dr Parks’ expert opinion
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.
Goal: Listeners will develop an approach to managing common orthopedic complaints, specifically knee pain, in the primary care setting.
Learning objectives: After this episode, learners will:
- Take a history from a patient with knee pain and recall the four main buckets of knee pain
- Perform an effective and efficient physical exam on the knee
- Order the appropriate x-rays of the knee
- Discuss corticosteroid injections and NSAID use for knee pain
- Counsel patients on knee braces
- Identify red flags and patients who require a referral to orthopedic surgery
- Counsel patients on next generation therapy for knee osteoarthritis like platelet rich plasma and stem cell therapy
Disclosures: Dr Parks, in association with American College of Physicians, is the author of the McGraw Hill Textbook Practical Office Orthopedics and receives royalties from book sales.
- 00:00 Announcement
- 01:00 Disclaimer
- 01:35 Intro and guest bio
- 04:08 Dr Parks’ one-liner, book recommendation, inventions, and career advice
- 10:52 A case of knee pain, and recognizing emergencies
- 14:17 Four buckets of knee pain
- 17:40 Initial approach to treatment of knee pain
- 20:19 Corticosteroid injection controversy
- 22:47 Hyaluronic acid injections
- 24:50 Topical agents
- 27:03 Taking a history about knee pain
- 29:39 Knee locking or giving out
- Practical Office Orthopedics by Ted Parks
- 31:44 How to order knee X-rays
- 36:45 Knee braces
- 41:00 How to perform a 30 second knee exam
- Ms Anita Bones has left knee pain and recent fall.
- 53:00 PRP, stem-cell injections
- 61:00 Glucosamine chondroitin
- 63:09 Take home points
- 64:36 Outro
Links from the show:
- Practical Office Orthopedics (book) by Ted Parks (McGraw hill, 2017)
- Dr. Parks’ 30 Second Knee Exam Video on YouTube.
Do some Pre-/Post-show Reading on primary care orthopedics and division of labor between PCPs and orthopedists:
- Simonelli et al. Barriers to osteoporosis Identification and treatment among primary care physicians and orthopedics surgeons. Mayo Clinic Proceedings. April 2002. vol 77(4).
- Glazier et al. Management of common musculoskeletal problems: survey of Ontario primary care physicians. CMAJ. 1998; 158(8).
- Jordan et al. Annual consultation prevalence of regional musculoskeletal problems in primary care: an observational study. BMC Musculoskeletal Disorders. 2010; 11.
- Jordan et al. Measuring disease prevalence: a comparison of musculoskeletal disease using four general practice consultation databases. Br J Gen Pract. 2007;57(534).
- Glazier et al. Determinants of physician confidence in primary care management of musculoskeletal disorders. 1996. The Journal of Rheumatology; 23(2).
- National Clinical Guideline Center. Osteoarthritis: care and management in adults. National Institute for Health and Clinical Excellence: Guidance, London 2014.