In a patient with a total hip arthroplasty who now has left hip and groin pain after slipping, what is the appropriate urgent evaluation and management?

Urgent Evaluation and Management of Hip and Groin Pain After Slip in Total Hip Arthroplasty Patient

Immediately obtain anteroposterior pelvis and lateral hip radiographs comparing them to immediate postoperative films to detect periprosthetic fracture, component migration, or progressive lucencies, as this is the most critical first step to rule out fracture-related morbidity and mortality. 1, 2, 3

Initial Clinical Assessment

Determine the pain pattern to guide your diagnostic approach:

• Night-time or resting groin pain strongly indicates periprosthetic infection and requires urgent infection work-up 2
• Weight-bearing-related groin pain suggests mechanical failure such as periprosthetic fracture, aseptic loosening, or component wear 2

After a slip or fall, periprosthetic fracture is the most urgent concern—postoperative periprosthetic fractures occur in 0.52% of cases and are the most common cause for readmission and reoperation 4. These fractures carry high morbidity if diagnosis is delayed 3, 5.

Radiographic Evaluation

Compare current radiographs to immediate postoperative films and look for:

• Periprosthetic fracture (most urgent) 1, 2
• Component migration or subsidence 2
• Progressive lucencies >2 mm at the bone-prosthesis interface 2
• Osteolysis (expansile well-defined lucent lesions) 2
• Greater trochanter avulsion or surface irregularities >2 mm 1

Critical pitfall: Plain radiographs miss 24.1% of hip fractures in elderly trauma patients 3. Do not rely on preserved range of motion or weight-bearing ability to exclude fracture—patients with minimally displaced fractures can maintain function initially 6.

Advanced Imaging When Radiographs Are Negative or Equivocal

If radiographs are negative but clinical suspicion for periprosthetic fracture remains high after trauma:

• Obtain nonenhanced multidetector CT hip immediately 1, 3
• CT has 94% sensitivity and 100% specificity for detecting radiographically occult hip fractures 3
• CT detects occult fractures in 24.1% of patients with negative radiographs and changes management in 20% of cases 3
• Do not order CT with IV contrast for fracture detection—there is no additional benefit 1
• Contrast is only helpful if vascular injury is suspected 1

If infection cannot be excluded based on clinical presentation (night pain, fever, elevated inflammatory markers):

• Perform image-guided hip aspiration for synovial fluid cell count, differential, culture, and sensitivity—this is the most reliable test for confirming or excluding infection 2
• If aspiration is positive or highly suspicious, combined white-blood-cell scan and sulfur-colloid scan provides 88%–100% specificity for periprosthetic infection 2

Pain Management During Evaluation

While diagnostic work-up is underway:

• NSAIDs or COX-2 selective inhibitors are first-line analgesics 2
• Paracetamol (acetaminophen) combined with NSAIDs provides effective multimodal analgesia 2
• Avoid long-term opioid therapy; reserve opioids only for rescue analgesia 2
• Allow weight-bearing as tolerated with assistive device (crutches or walker) to prevent deconditioning 6
• Do not prescribe complete bed rest—immobility increases complications 6

When to Obtain MRI

MRI with metal-artifact-reduction sequences is indicated when:

• Radiographs and CT are negative but pain persists or worsens at 1-2 weeks 6
• Soft-tissue pathology is suspected (iliopsoas tendonitis, abductor tendon tears, trochanteric bursitis) 2
• MRI detects osteolysis with 95.4% sensitivity and identifies regional lymphadenopathy with 93.1% accuracy for distinguishing infected from uninfected implants 2

However, MRI has limitations: Nondisplaced fractures may be difficult to see if there is only mild marrow edema, and susceptibility artifact from the prosthesis may obscure findings 1.

Treatment Algorithm Based on Findings

If periprosthetic fracture is confirmed:

• Treatment depends on fracture location, implant stability, and bone stock 5, 7
• Fractures with well-fixed implants typically require open reduction and internal fixation 7
• Fractures with loose implants require revision arthroplasty with fracture stabilization 7
• Urgent orthopedic consultation is mandatory—delayed treatment increases short-term and mid-term mortality 3

If infection is confirmed:

• Specific operative treatment usually involves revision of the acetabular component or other procedures depending on the extent of infection 8

If soft-tissue pathology is identified (iliopsoas tendonitis, abductor tears):

• Non-operative treatment is usually unsuccessful 8
• Specific operative treatment such as iliopsoas tenotomy is usually successful 8

Common Pitfalls to Avoid

• Do not rely on clinical signs alone to exclude fracture 3
• Do not increase the number of radiographic projections instead of proceeding to CT—this does not decrease the need for cross-sectional imaging 3
• Do not assume normal radiographs exclude fracture in a patient with significant trauma—proceed to CT 6
• Do not use bone scan in acute traumatic evaluation—there is insufficient evidence 1, 3
• Recognize that 15% of periprosthetic fractures develop loosening following treatment, suggesting underrecognition of implant instability at the time of injury 9