What is the appropriate evaluation and management for a 68‑year‑old woman presenting with knee pain and cramping and peeling of the hands, whose radiographs show mild‑to‑moderate multicompartmental knee osteoarthritis without osteophytes, polyarticular hand osteoarthritis (worst at the first carpometacarpal joint) with mild interphalangeal joint narrowing and soft‑tissue thickening near the proximal second digit, and no evidence of an acute fracture?

Evaluation and Management of Polyarticular Osteoarthritis with Atypical Features

This 68-year-old woman requires evaluation to exclude inflammatory arthritis (particularly psoriatic arthritis, rheumatoid arthritis, or calcium pyrophosphate deposition disease) before confirming a diagnosis of osteoarthritis alone, because the absence of osteophytes in the knee despite moderate joint space narrowing, combined with hand peeling and soft tissue thickening, raises concern for an inflammatory process.

Key Diagnostic Concerns

Atypical Radiographic Features Requiring Further Investigation

• The knee radiograph shows moderate multicompartmental joint space narrowing WITHOUT spurring (osteophytes), which is unusual for primary osteoarthritis 1
• Classical radiographic features of osteoarthritis include joint space narrowing, osteophytes, subchondral sclerosis, and subchondral cysts; the absence of osteophytes despite moderate narrowing is atypical 1
• Radiographic changes of hand osteoarthritis and calcium pyrophosphate deposition disease (CPPD) arthritis are extremely similar, and these conditions may coexist 1

Clinical Red Flags for Inflammatory Arthritis

• The complaint of "peeling of the hands" must be carefully examined for psoriatic skin changes, as psoriatic arthritis can target individual rays or DIP joints and may mimic osteoarthritis 1
• Soft tissue thickening of the proximal second digit on radiograph requires correlation with physical examination to distinguish inflammatory synovitis from osteoarthritic changes 1
• The differential diagnosis for hand arthritis includes psoriatic arthritis (which may affect just one ray), rheumatoid arthritis (mainly targeting MCPs, PIPs, wrists), gout (which may superimpose on pre-existing osteoarthritis), and haemochromatosis 1

Recommended Diagnostic Workup

Blood Tests to Exclude Inflammatory Arthritis

Blood tests are not required for diagnosis of osteoarthritis but ARE required to exclude coexistent inflammatory disease when atypical features are present 1:

• Order inflammatory markers (ESR, CRP) because marked inflammatory symptoms, atypical joint involvement, or absence of expected radiographic features warrant screening for inflammatory arthritides 1
• Consider rheumatoid factor (RF) and anti-CCP antibodies if rheumatoid arthritis is suspected 1
• Consider serum urate if gout is suspected, particularly given that gout may superimpose on pre-existing osteoarthritis 1
• Inflammatory markers are not usually elevated in osteoarthritis, so elevated CRP or ESR would support an inflammatory process 1

Physical Examination Priorities

• Examine the hands for psoriatic plaques, nail pitting, or onycholysis, particularly given the complaint of "peeling" 1
• Assess the soft tissue thickening of the second digit for warmth, tenderness, and whether it represents inflammatory synovitis versus bony enlargement 1
• Look for Heberden's nodes (DIP joints) and Bouchard's nodes (PIP joints), which are pathognomonic for osteoarthritis and essentially absent in rheumatoid arthritis 2
• Examine for soft tissue swelling (suggesting inflammatory arthritis) versus bony enlargement (suggesting osteoarthritis) 1

Additional Imaging Considerations

• The radiologist's recommendation for follow-up imaging in 10-14 days, MRI, or CT if persistent pain or occult fracture is suspected should be considered if symptoms do not improve with initial management 1
• Plain radiographs remain the gold standard for morphological assessment of osteoarthritis, and further imaging modalities are seldom indicated for diagnosis 1

Management Algorithm

If Inflammatory Arthritis is Excluded (Normal Labs, No Psoriatic Features)

Proceed with osteoarthritis management using a stepwise approach:

Non-Pharmacological Management (First-Line)

• All patients with hand osteoarthritis should be evaluated for ability to perform activities of daily living and receive assistive devices as necessary 1
• Provide instruction in joint protection techniques 1
• Instruct in use of thermal modalities for relief of pain and stiffness 1
• Provide splints specifically for the first carpometacarpal (thumb base) joint osteoarthritis, as patients may benefit from this device 1
• Education plus exercise programs are supported by research evidence for osteoarthritis management 1

Pharmacological Management (Stepwise)

Step 1: Topical NSAIDs (First-Line for Hand OA)

• Topical NSAIDs are conditionally recommended and supported by research evidence for hand osteoarthritis 1
• Topical diclofenac has demonstrated efficacy in knee osteoarthritis with reduction in WOMAC pain scores 3

Step 2: Oral NSAIDs or COX-2 Inhibitors

• Oral NSAIDs and COX-2 inhibitors are supported by research evidence for osteoarthritis 1
• Consider gastroprotective agents (PPIs) in patients with cardiovascular comorbidities or GI risk factors 1

Step 3: Intra-articular Corticosteroids for Flares

• Intra-articular injection of long-acting corticosteroid is effective for painful flares, especially trapeziometacarpal (thumb base) joint osteoarthritis 1
• One uncontrolled trial showed significant pain reduction at one month for thumb base osteoarthritis 1

Step 4: Consider Chondroitin Sulphate

• Chondroitin sulphate has been examined in hand osteoarthritis for structure-modifying effects, though results are inconclusive 1

If Inflammatory Arthritis is Confirmed

• Refer to rheumatology for consideration of disease-modifying antirheumatic drugs (DMARDs) or biological agents, particularly if erosive interphalangeal osteoarthritis is present 1
• Existing slow-acting antirheumatic drugs and biological agents (especially anti-TNF therapy) should be investigated in erosive interphalangeal osteoarthritis 1

Critical Pitfalls to Avoid

• Do not assume pure osteoarthritis when osteophytes are absent despite moderate joint space narrowing—this warrants investigation for inflammatory or crystalline arthropathy 1
• Do not dismiss "peeling of the hands" without examining for psoriatic skin changes, as psoriatic arthritis can closely mimic osteoarthritis in distribution 1
• Do not ignore soft tissue thickening on radiographs—correlate with physical examination to distinguish inflammatory synovitis from osteoarthritic changes 1
• Osteoarthritis and inflammatory arthritis (CPPD, gout, rheumatoid arthritis) may coexist in the same patient 1