Modern Study Review (AI-Generated)
High-Yield Summary
Paget’s disease of bone presents unique challenges in total hip arthroplasty (THA) due to abnormal bone remodeling characterized by excessive osteoclastic resorption followed by disorganized osteoblastic bone formation. This leads to altered proximal femoral and acetabular anatomy, including varus deformity and protrusio acetabuli, complicating implant fixation and alignment. Careful preoperative planning, medical optimization, and intraoperative techniques tailored to hypervascular, sclerotic, and deformed bone are essential to optimize outcomes. Despite advances, THA in Paget’s disease carries a higher risk of complications and revision compared to standard osteoarthritis cases.
Key Diagnostic Findings
| Aspect | Details |
|---|---|
| Pathophysiology | Excessive osteoclastic resorption ? disorganized osteoblastic bone deposition ? phases: osteolytic ? mixed lytic/blastic ? osteosclerotic |
| Laboratory Markers | Elevated serum alkaline phosphatase (ALP), elevated urine hydroxyproline (bone turnover markers) |
| Anatomical Changes | Varus bowing of proximal femur (coxa vara), acetabular protrusio, lateral tension-side stress fractures |
| Clinical Presentation | Hip pain often secondary to altered biomechanics and secondary osteoarthritis; must exclude Pagetoid sarcoma and radiculopathy |
| Imaging | Full-length standing femur films to assess deformity; standard hip radiographs to evaluate acetabular protrusio and sclerosis |
| Classification | No specific Paget’s classification for THA; deformity and bone quality guide surgical planning |
Current Gold Standard Treatment
| Treatment Phase | Recommendations |
|---|---|
| Preoperative | – Confirm hip as pain source; consider intra-articular anesthetic injection – Baseline ALP and urine hydroxyproline – Medical optimization with bisphosphonates or calcitonin to reduce hypervascularity – Cardiac evaluation due to risk of high-output failure from extensive bone involvement – Full-length femur imaging for deformity assessment |
| Operative | – Cemented femoral fixation remains gold standard due to wide, sclerotic canals and poor bone quality – Cemented or cementless acetabular fixation based on bone quality; be prepared for bone grafting or use of protrusio cages – Anticipate hypervascularity: use cell saver, meticulous hemostasis – Use sharp reamers and power tools for sclerotic bone; avoid broaching if bone is brittle – Consider intraoperative imaging and possible femoral osteotomy for severe varus deformity – Use large cement restrictors and abundant cement for fixation |
| Postoperative | – Prophylaxis for heterotopic ossification with NSAIDs or low-dose radiation therapy – Monitor for complications and optimize rehabilitation |
Modern Complications & Outcomes
| Complication | Notes |
|---|---|
| Higher Revision Rates | Due to poor bone quality, deformity, and implant loosening |
| Heterotopic Ossification | Common; prophylaxis recommended |
| Intraoperative Fractures | Risk increased with sclerotic, brittle bone and deformity |
| Hypervascularity | Increased bleeding risk; may impair cement interdigitation |
| Cardiac Complications | High-output cardiac failure in extensive disease |
| Functional Outcomes | Generally inferior to standard THA; pain relief achieved but with higher complication risk |
Classic Clinical Notes
Paget’s/THA
Approach to Hip Arthroplasty in Paget’s Disease
Remember a few points about Paget’s disease:
- A disease set off by excessive osteoclast resorption of bone, coupled with a desperate response by the osteoblasts to lay down new bone which is disorganized and ultrastructurally inadequate.
- Involves an osteolytic phase, followed by a mixed lytic/blastic phase, followed by a final osteosclerotic phase.
- Can be followed in the lab by elevated alk phos and urine hydroxyproline levels.
In the Hip:
- Varus bowing of the proximal femur and coxa vara.
- Acetabular protrusio.
- Stress fractures on the lateral, tension side.
- Osteoarthritis is probably secondary to altered morphology and biomechanics of weightbearing.
Preoperatively
- Start by making sure that the pain is actually coming from the hip – MAKE SURE THEY DON’T HAVE A PAGETOID SARCOMA!!! Also, rule out RADICULOPATHY from spinal involvement, STRESS FRACTURE, and simple PAGET’S BONE PAIN. Consider an intra-articular marcaine injection to sort this out.
- Check alk phos and urine hydroxyproline to just get a baseline for their Paget’s disease.
- Consult internal medicine/Rheumatology if considering surgery – will the patient benefit from being put on bisphosphonates and calcitonin preop?
- Get full length standing films to assess the deformity of the entire femur.
- Make sure cardiac status is okay – 15% involvement of bone can lead to cardiac changes (high output failure).
- Anticipate that heterotopic bone formation is a problem in these patients – postop they will need NSAIDs or XRT.
Technical Considerations – Femur
- On the femoral side, despite the limitations, cemented fixation is still the gold standard – have lots of cement!
- Hypervascularity – may impair visualization, require measures such as a cell saver, and may compromise cement fixation because of an inability to achieve a really dry field for cement interdigitation; also, theoretically there is a potential risk for osteolytic bone resorption during the hypervascular stage. May also be an issue for acetabular fixation; you might have to consider cementing both the femur and the acetabulum!
- Be ready for this preop with calcitonin or bisphosphonates.
- Bone sclerosis – it can be extremely hard; have sharp reamers and the midas rex. May not be able to use the broaches, because the bone is so hard and you may just break it by pounding down the reamers.
- Varus bowing – anticipate the need to get an intraoperative x-ray to confirm that you are down the middle. Also be ready to osteotomize the femur to get it straight, and preoperatively template to make sure you can bypass this.
- Size of canal – it is often very wide; need a huge cement restrictor (or bone plug) with lots of cement.
Technical Considerations – Acetabulum
- On the acetabular side, cemented or cementless are acceptable (no good comparisons) – have to decide once you see the quality of bone.
- Protrusio – makes the exposure more difficult; anticipate the need for a wide exposure; be prepared to osteotomize in situ, be prepared to bone graft or use a protrusio cage, with rim reaming only to open the mouth of the acetabulum but not deepen it.
Results:
As a whole, the results in this patient population are inferior, with a much higher revision rate.
Last Updated on January 24, 2026 by orthonet
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