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Knee Osteoarthritis (OA)

Andrew Buelt, DO and Jake Anderson, DO

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Jake and Andrew break down the data for us on knee OA treatments. Lo and behold, there is not a lot of evidence!


  • Knee osteoarthritis is extremely common and is a clinical diagnosis.

  • Weight loss, exercise therapy (land-based may be better than aquatic), NSAIDs are first-line treatment. Topical NSAIDs may be just as effective with fewer side effects.

  • Bracing/taping/wedge inserts have limited efficacy data.

  • Steroid injections while common actually have little data demonstrating effectiveness and may lead to increased knee cartilage loss.


  • Why is knee OA important? Affects one-fifth of the US population and is one of the most common causes of pain and disability.

    • Knee OA is the most prevalent form of OA in women (13%) and men (10%) over 60.

  • Presentation: knee pain that worsens with prolonged activity, crepitus on exam.

  • Diagnosis: clinical

    • Combination of age > 50, presence of bony enlargement, crepitus and no palpable warmth is 92% sensitive and 75% specific for knee OA with a positive likelihood ratio of 3.7.

    • If you’re concerned about inflammatory or infectious process consider X-ray, aspiration and lab testing.

      • X-rays really aren’t necessary if the story fits. But you will see joint space narrowing, bony spurs, subchondral sclerosis/thickening.

      • You can also aspirate the knee if you palpate an effusion and want to send for inflammatory or infectious arthritis work-up.

      • If just OA, the aspirate will reveal a clear synovial fluid with a white blood cell count less than 2000 per uL, an ESR <40 and rheumatoid factor less than 1:40.

  • Treatment:

    • Weight loss for BMI > 25 through calorie restriction and exercise.

    • Exercise therapy: no recommended strategy other than self-management programs that include strengthening, low impact aerobic exercise and neuromuscular education.

      • Cochrane review in 2015 of 54 randomized clinical trials showed some benefit in pain and function with land-based exercises as opposed to aquatic exercise.

      • Cochrane review in 2016 of 13 aquatic therapy vs control in randomized control trials did find improvement in pain, disability and quality of life but did disappear after 4-24 weeks post-intervention.

    • Bracing/wedge inserts/taping: limited evidence of effectiveness.

    • Acetaminophen: number needed to treat between 4 and 16 but this is based on Cochrane review from 2006 that showed those taking properly dosed (1000mg, 4 times a day) improved 4 points on a 100 point scale.

      • American College of Rheumatology still recommends as initial management but American College of Orthopedic Surgeons no longer recommends for or against it.

    • NSAIDs:

      • There doesn’t seem to be a superior NSAID.

      • Be careful in older patients, those with a history of GI bleed and definitely stay away if they have Stage 4 or 5 kidney disease.

      • Topical NSAIDs may be just as effective as oral agents with less GI side effects.

      • Check out the July 2017 PCRAP Paper Chase for more details on topical NSAIDs.

    • Tramadol:

      • Cochrane review of 10 randomized trials showed only small benefit (8 points on 100 point scale).

      • Cepeda MS et. al. Tramadol for osteoarthritis. Cochrane Database Syst Rev. 2006 Jul 19;(3):CD005522. Review. PMID: 16856101.

    • Opioids:

      • Minimal benefit (0.7 on a 10-point scale) with high risk potential.

      • da Costa BR et. al. Oral or transdermal opioids for osteoarthritis of the knee or hip. Cochrane Database Syst Rev. 2014 Sep 17;(9):CD003115. PMID: 25229835.

    • Chondroitin sulfate:

      • Data is mixed - Cochrane review in 2015 looked at 800mg per day v. placebo and found pain reduction at less than 6 months, 10 points on a 100 point scale and number needed to treat of 5.

        • Singh JA et. al. Chondroitin for osteoarthritis. Cochrane Database Syst Rev. 2015 Jan 28;1:CD005614. PMID: 25629804.

        • American Academy of Orthopedic Surgeons recommends against using glucosamine for treatment of knee OA.

    • Duloxetine: three studies have shown improvement in pain with number needed to treat of 5 for 50% pain improvement. Data for widespread use is not available.

    • Steroid injections: Have been used since the 1950’s but the data is limited.

      • American Academy of Orthopedic Surgeons is unable to recommend for or against it because of the lack of data, which is a change from 2008 when they recommended it.

      • Cochrane review in 2015 of 27 randomized control trials that had over 7500 patients was unable to draw conclusions due to the small size of the heterogeneous trials.

        • Jüni P et. al. Intra-articular corticosteroid for knee osteoarthritis. Cochrane Database Syst Rev. 2015 Oct 22;(10):CD005328. PMID: 26490760.

      • Study from October 2017 in Journal American Academy of Orthopedic Surgery is the most recent data.

        • 100 patients with mean age of 61, BMI of 31. They all received injections of about 10mg triamcinolone with 4ml of 1% lidocaine without epinephrine. There was no comparison group.

        • They did find improvement in pain scores.

        • Matzkin EG et. al. Efficacy and Treatment Response of Intra-articular Corticosteroid Injections in Patients With Symptomatic Knee Osteoarthritis. J Am Acad Orthop Surg. 2017 Oct;25(10):703-714. PMID: 28953085.

      • Double-blind RCT in May 2017 compared steroid injection with saline injection.

        • 140 adults, 45 years or older with knee OA, were randomly assigned to group (steroid or saline) every 3 months for 2 years.

        • Pain and functional scores were no different.

        • There was cartilage damage on the MRI for those receiving steroids.

Hyaluronic acid injection: largely mixed results and is very expensive.

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The Tragically Sore Hip Full episode audio for MD edition 196:52 min - 92 MB - M4AHippo Primary Care RAP - February 2018 Written Summary 339 KB - PDF