What is the approach to assessing and managing knee pain?

Approach to Assessing and Managing Knee Pain

Begin with a structured biopsychosocial assessment that includes physical status (pain characteristics, joint alignment, mobility, strength, comorbidities, weight), activities of daily living, participation in work/leisure, mood, and health education needs, then tailor treatment based on the underlying diagnosis using a combination of non-pharmacological and pharmacological interventions. 1, 2

Initial Assessment Components

History Taking

• Document pain location, onset (gradual vs. acute), duration, quality, and intensity to narrow the differential diagnosis 2, 3
• Identify mechanical symptoms such as locking, catching, or giving way that suggest meniscal or ligamentous pathology 3
• Assess for systemic symptoms including fever, which may indicate septic arthritis requiring urgent evaluation 3
• Determine the presence and timing of swelling—immediate swelling suggests hemarthrosis from ligamentous rupture or fracture, while delayed swelling indicates inflammatory processes 4, 3
• Evaluate risk factors including obesity, adverse mechanical factors, physical activity level, age, and comorbidities 1, 2

Physical Examination

• Inspect for visible deformity, swelling, erythema, muscle atrophy, and gait abnormalities 1, 3
• Palpate systematically to localize tenderness to specific structures (joint line, patella, tibial tubercle, pes anserine bursa) 3
• Assess range of motion actively and passively, noting any limitations or crepitus 1, 3
• Test muscle strength, particularly quadriceps and hip abductors, as weakness contributes to patellofemoral dysfunction 1, 5
• Perform ligamentous stability testing including Lachman test and pivot shift for ACL integrity 6
• Evaluate joint alignment, proprioception, and posture as these affect loading patterns 1

Imaging Strategy

• Obtain plain radiographs (frontal projection, tangential patellar view, lateral view) as the initial imaging study for chronic knee pain lasting more than 6 weeks 2, 3
• Reserve radiographs for acute traumatic pain only in patients meeting evidence-based criteria (inability to bear weight, severe pain with instability) 3, 7
• Consider ruling out referred pain from hip or lumbar spine if knee radiographs are unremarkable 2
• Avoid ordering MRI without recent radiographs, which occurs inappropriately in approximately 20% of chronic knee pain cases 2
• Use MRI only when surgery is contemplated or when symptoms persist despite adequate conservative treatment 3, 7

Management Based on Diagnosis

For Knee Osteoarthritis

Non-Pharmacological Interventions (First-Line)

• Prescribe regular education about the condition, self-management strategies, and realistic expectations for recovery 1
• Implement joint-specific exercises including quadriceps strengthening and range of motion exercises, which show an effect size of 0.52-1.0 for pain reduction 1, 6
• Recommend 30-60 minutes of moderate-intensity aerobic activity on most days, either supervised or home-based 1, 6
• Counsel on weight reduction with a minimum 5% body weight loss target for patients with BMI ≥25 kg/m², combining dietary modification with exercise 1, 6
• Provide appropriate footwear recommendations and consider assistive devices (canes, walkers) when needed 1, 2
• Consider prefabricated foot orthoses for biomechanical correction, but avoid lateral wedge insoles which lack efficacy 2, 6

Pharmacological Management (Stepwise Approach)

• Start with paracetamol (acetaminophen) as the first-line oral analgesic for mild to moderate pain 1, 2
• Add topical NSAIDs or capsaicin if paracetamol provides inadequate response, as these have clinical efficacy with excellent safety profiles 1, 2
• Prescribe oral NSAIDs at the lowest effective dose for patients unresponsive to paracetamol, using gastroprotective agents or selective COX-2 inhibitors in patients with increased gastrointestinal risk 1, 2
• Consider opioid analgesics with or without paracetamol as alternatives when NSAIDs are contraindicated, ineffective, or poorly tolerated 1

Intra-Articular Interventions

• Administer intra-articular corticosteroid injections (20-80 mg for large joints like the knee) for acute flares of pain, especially when accompanied by effusion 1, 8
• Ensure injection into the synovial space using sterile technique with a 20-24 gauge needle, as treatment failures most frequently result from failure to enter the joint space 8
• Repeat injections at intervals ranging from one to five or more weeks depending on degree of relief, though repeated injections are usually futile if initial properly-placed injections fail 8
• Consider hyaluronic acid injections conditionally, though evidence is less robust than for corticosteroids 9

Advanced Options

• Refer for radiofrequency ablation (conventional or cooled) of genicular nerves when conservative treatment fails, as this has demonstrated effectiveness 9
• Consider joint replacement surgery for patients with radiographic evidence of knee OA who have refractory pain and disability despite comprehensive conservative management 1

For Patellofemoral Pain Syndrome

Exercise Therapy (Foundation of Treatment)

• Prescribe individualized knee-targeted exercise therapy as the primary treatment, focusing on quadriceps strengthening 5
• Add hip abductor strengthening exercises (side-lying leg raises, clamshells) based on individual assessment findings, as patients with patellofemoral pain are often weaker in hip musculature 5
• Combine hip and knee strengthening exercises with patellar taping for symptom relief during activity 2, 5

Education and Adjunctive Measures

• Explain that pain does not necessarily correlate with tissue damage and set realistic expectations about recovery timeframes, as over 50% of patients report persistent pain more than 5 years post-diagnosis 5
• Use prefabricated foot orthoses when patients respond favorably to treatment direction tests, particularly beneficial in the short term 5
• Apply patellar taping and manual therapy (soft tissue mobilization of lateral retinacular structures and iliotibial band) as adjuncts to facilitate exercise therapy when rehabilitation is hindered by high symptom severity or fear of movement 5
• Screen for anxiety or depression, as patients with patellofemoral pain are six times more likely to experience these conditions 5

Reassessment Strategy

• If no improvement occurs after 6-8 weeks of consistent therapy, reassess the diagnosis and consider imaging (radiographs or MRI) to rule out other pathologies 5

For Bursitis

• Treat with oral or topical NSAIDs combined with quadriceps strengthening exercises and pressure-reducing measures 6
• For aspiration and injection, prepare the area sterilely, insert a 20-24 gauge needle into the bursa, aspirate fluid, then inject 4-30 mg of corticosteroid depending on the condition severity 8

For Acute Ligamentous Injuries

• Refer active patients with ACL tears who desire return to cutting/pivoting sports for ACL reconstruction with autograft 6
• Recognize that acute knee joint swelling with hemarthrosis following trauma suggests ligamentous rupture or fracture requiring urgent evaluation 4, 3

Common Pitfalls to Avoid

• Failing to address weight management in overweight patients with osteoarthritis, as this is a modifiable risk factor with significant impact 6
• Focusing only on knee exercises without addressing hip strength in patellofemoral pain syndrome, which limits treatment effectiveness 5
• Over-reliance on imaging without adequate trial of conservative management, particularly ordering MRI without recent radiographs 2, 5
• Injecting corticosteroids into surrounding tissue rather than the synovial space, which provides little to no benefit 8
• Prescribing lateral wedge insoles for knee osteoarthritis, as these lack evidence for efficacy 6
• Inadequate patient education about the condition, leading to poor adherence with exercise therapy and unrealistic expectations 5
• Missing septic arthritis in patients presenting with fever, swelling, erythema, and limited range of motion, which requires urgent intervention 3
• Overlooking referred pain from hip pathology (such as slipped capital femoral epiphysis in adolescents) or lumbar spine when knee examination is unremarkable 2, 4