What is the appropriate history and physical examination, differential diagnosis, and assessment plan for a patient 5 days post left hip arthroplasty (total hip replacement) with suspected deep vein thrombosis (DVT)?

History and Physical Examination for Suspected DVT Post Left Hip Arthroplasty

Chief Complaint and History of Present Illness

A patient 5 days post left hip arthroplasty presenting with suspected DVT requires immediate evaluation focusing on leg pain, swelling, and risk stratification, as this represents a high-risk scenario for proximal DVT with potential life-threatening pulmonary embolism. 1

Key Historical Elements to Document

Symptom Characterization:

• Pain location and quality: Document if pain is in the calf, thigh, or inguinal region, as DVT can present with severe inguinal and hip pain that may be mistaken for musculoskeletal pain 2
• Onset and progression: Note when symptoms began relative to surgery (early DVT can develop within 2 days post-hip surgery) 3
• Leg swelling: Present in 80% of DVT cases, though approximately one-third of DVT patients are completely asymptomatic 4, 5
• Erythema: Observed in 26% of DVT patients 4

Surgical and Risk Factor History:

• Type of arthroplasty: Total hip arthroplasty carries a 34% risk of asymptomatic DVT 6
• Thromboprophylaxis regimen: Document what anticoagulation was used postoperatively 6
• Previous DVT history: Patients with prior DVT have venous wall thickening that increases proximal DVT risk 7.8-fold 3
• Mobility status: Document ambulation since surgery 6

Physical Examination

Vital Signs:

• Assess for tachycardia, tachypnea, hypoxia: May indicate concurrent pulmonary embolism 1

Lower Extremity Examination (Compare Left to Right):

• Circumferential measurements: Measure calf and thigh circumference bilaterally at standardized points 5
• Edema assessment: Document extent (foot, ankle, calf, entire leg) 4, 5
• Skin changes: Erythema, warmth, dilated superficial veins 5
• Tenderness: Palpate along venous distribution from groin to calf 2, 5
• Surgical site: Assess for hematoma or infection that could mimic DVT 5

Cardiopulmonary Examination:

• Assess for signs of pulmonary embolism: Tachypnea, decreased oxygen saturation, pleuritic chest pain 1

Differential Diagnosis

Primary Consideration

• Proximal DVT (popliteal, femoral, or iliac vein thrombosis): Most likely given timing and risk factors; carries 25-30% mortality if untreated due to pulmonary embolism risk 1

Alternative Diagnoses to Consider

• Distal (calf) DVT: Lower risk than proximal but can propagate proximally in 10-15% of cases within 2 weeks 1
• Postoperative hematoma: Can cause pain and swelling but typically more localized to surgical site 5
• Cellulitis: Presents with erythema, warmth, and systemic signs of infection 5
• Muscle strain or contusion: May occur with early mobilization but less likely to cause diffuse leg swelling 2
• Post-thrombotic syndrome from prior DVT: Relevant if patient has history of previous DVT with venous wall thickening 3
• Ruptured Baker's cyst: Causes acute calf pain and swelling 5

Assessment and Plan

Immediate Diagnostic Workup

Start Anticoagulation Immediately While Awaiting Imaging:

• Begin parenteral anticoagulation now given high clinical suspicion in post-hip arthroplasty patient with leg symptoms, as the risk of life-threatening pulmonary embolism far outweighs bleeding risks 1
• Low-molecular-weight heparin (LMWH) is preferred as first-line agent 1
• Alternative options: Fondaparinux or unfractionated heparin (if severe renal impairment) 1

Obtain Complete Duplex Ultrasound (CDUS):

• Order complete duplex ultrasound from common femoral vein to ankle as the definitive diagnostic test 7
• Imaging should be performed urgently (within hours, not days) given high clinical suspicion 7
• If CDUS unavailable immediately: Extended compression ultrasound (ECUS) from thigh to knee is acceptable, but requires repeat CDUS in 5-7 days to exclude distal DVT 7

Laboratory Studies:

• Complete blood count with platelets: Baseline before anticoagulation 4
• PT/INR and aPTT: Baseline coagulation studies 4
• Creatinine: To guide anticoagulant dosing 4
• D-dimer is NOT recommended when clinical suspicion is high and ultrasound is readily available, as it will not change management 7

Management Based on Ultrasound Results

If Proximal DVT Confirmed (Popliteal, Femoral, or Iliac Vein):

• Continue anticoagulation for minimum 3 months as this is provoked DVT (surgery within 3 months) 1
• LMWH bridged to warfarin OR direct oral anticoagulant (DOAC) such as apixaban or rivaroxaban 1, 5
• No repeat imaging needed unless symptoms worsen or management changes 7
• Consider compression stockings to prevent post-thrombotic syndrome, which develops in approximately 50% of proximal DVT cases 7, 1

If Distal (Calf) DVT Only:

• Two management options: Either treat with anticoagulation for 3 months OR serial ultrasound surveillance 7, 1
• If choosing surveillance: Repeat ultrasound in 1 week to assess for proximal extension, then again at 2 weeks 7
• Favor treatment over surveillance if: Extensive calf thrombosis, severe symptoms, positive D-dimer, or inability to return for follow-up 7

If Initial Ultrasound Negative but High Clinical Suspicion:

• Continue anticoagulation and repeat ultrasound in 5-7 days to exclude propagating distal DVT 7
• Consider iliocaval imaging (CT or MR venography) if extensive leg swelling persists, as isolated iliac DVT may be missed on standard ultrasound 7

Critical Pitfalls to Avoid

• Never withhold anticoagulation for confirmed proximal DVT while awaiting additional testing, as untreated proximal DVT has 25-30% mortality from pulmonary embolism 1
• Do not dismiss symptoms as "normal postoperative pain" in hip arthroplasty patients, as 43% of postoperative DVTs are detected by day 2 3
• Do not rely on clinical examination alone to exclude DVT, as one-third of patients are asymptomatic 4
• Recognize that asymptomatic DVT after hip arthroplasty is common (34%) and can lead to post-thrombotic syndrome in 25% of above-knee cases despite treatment 6
• If patient has history of prior DVT: Obtain baseline ultrasound to document venous wall thickening, which increases proximal DVT risk 7.8-fold 3

Follow-Up and Monitoring

• Outpatient management is appropriate if hemodynamically stable, no pulmonary embolism, and able to comply with anticoagulation 1
• Monitor for bleeding complications on anticoagulation 5
• Assess for pulmonary embolism symptoms: Chest pain, dyspnea, hemoptysis 1
• Long-term: Monitor for post-thrombotic syndrome development (chronic leg pain, swelling, skin changes) which occurs in 50% of proximal DVT cases 7, 1