Causes of Bipolar Hemiarthroplasty Surgery

Introduction

Bipolar hemiarthroplasty is a commonly performed orthopedic procedure, especially for elderly patients who have suffered severe hip injuries. While it is often associated with fractures, there are actually multiple underlying conditions that can lead to the need for this type of surgery. Understanding these causes of bipolar hemiarthroplasty surgery helps patients, families, and caregivers make informed decisions about treatment, recovery, and future prevention.

What Is Bipolar Hemiarthroplasty?

Before diving into the causes, it’s important to understand what the procedure involves. Bipolar hemiarthroplasty is a type of partial hip replacement in which the damaged femoral head (the ball of the hip joint) is removed and replaced with a prosthetic implant. Unlike total hip replacement, only the ball of the joint is replaced while the socket (acetabulum) is left intact.

The term “bipolar” refers to the implant design, where there are two points of articulation – one between the prosthetic head and the acetabulum, and another within the implant itself. This dual mobility reduces friction and helps improve range of motion, especially beneficial for elderly patients.

Causes of Bipolar Hemiarthroplasty Surgery

1. Hip Fractures :- The leading cause of bipolar hemiarthroplasty is femoral neck fractures, particularly in older adults. These fractures occur in the upper part of the thigh bone, close to the hip joint. They usually happen due to

• Osteoporosis :- With aging, the density and strength of bones decrease. Osteoporosis makes bones brittle, significantly raising the risk of hip fractures even from minor falls. In such cases, the blood supply to the femoral head may be compromised, making reconstruction difficult. Replacing the femoral head becomes the most effective treatment, which is why bipolar hemiarthroplasty is often recommended.
• Low-energy falls :- For elderly individuals, a simple slip in the bathroom, a sudden step on uneven flooring, or loss of balance can lead to a serious hip injury. Studies show that falls in people over 65 account for a large percentage of femoral neck fractures.

High-impact trauma :- Younger patients may also need bipolar hemiarthroplasty if they experience severe trauma such as

• Road accidents
• Sports injuries
• Industrial or workplace accidents

When reconstruction is not feasible due to fracture displacement, surgery becomes necessary.

2. Avascular Necrosis (AVN) of the Femoral Head :- Another significant cause of this surgery is avascular necrosis, a condition where the blood supply to the femoral head is interrupted. Without adequate blood flow, bone tissue starts to die, leading to

• Severe pain
• Loss of mobility
• Collapse of the femoral head

Avascular necrosis can be triggered by

• Long-term steroid use :- Common in patients with autoimmune disorders or chronic inflammation.
• Alcoholism :- Heavy alcohol consumption damages blood supply to the bone.
• Trauma :- Past injuries may impair blood circulation, eventually leading to AVN.
• Medical conditions :- Such as sickle cell disease or autoimmune disorders. When the femoral head collapses, a bipolar hemiarthroplasty becomes the preferred surgical option because it restores mobility and reduces pain more effectively than conservative methods.

3. Osteoarthritis and Rheumatoid Arthritis :- Although osteoarthritis typically leads to total hip replacement, in some cases doctors choose bipolar hemiarthroplasty, especially when the damage is primarily confined to the femoral head.

• Osteoarthritis :- This is a degenerative joint condition where cartilage gradually wears away, causing chronic pain and stiffness. If only the femoral head is severely worn, replacing it with a bipolar prosthesis provides relief.
• Rheumatoid Arthritis :- This autoimmune disease causes chronic inflammation in joints. Prolonged inflammation can destroy the femoral head, making hemiarthroplasty necessary when conservative treatment fails.

Patients with arthritis may benefit from bipolar implants due to the reduced friction and better mobility offered by the dual-bearing system.

4. Failed Previous Hip Surgeries :- Some patients require bipolar hemiarthroplasty because their previous surgeries did not yield satisfactory results. These include

• Failed internal fixation :- When screws, plates, or rods used to fix a fracture do not heal or the bone collapses, doctors may recommend replacing the femoral head.
• Hardware complications :- Loosening, breakage, or implant migration can cause pain and instability.
• Infections :- Severe infections that damage bone tissue may require removal of diseased bone and replacement with a prosthetic.

In such revisions, bipolar hemiarthroplasty provides stability and can be a safer alternative to total hip replacement, depending on the condition of the acetabulum.

5. Tumors and Bone Cysts in the Hip :- Bone tumors whether benign or malignant can weaken the structural integrity of the femoral head. If the tumor destroys the bone or if surgical removal creates a defect, doctors may need to replace the femoral head using bipolar hemiarthroplasty.

Common tumor-related causes include

• Metastatic bone disease
• Primary bone cancers
• Aggressive bone cysts
• Tumors affecting the femoral neck

This approach helps preserve the patient’s mobility while removing diseased tissue.

6. Chronic Hip Pain With Loss of Function :- In rare cases, patients have chronic hip pain caused by long-standing conditions that severely damage the femoral head. When the pain begins to interfere with daily activities, such as walking, climbing stairs, or standing for long periods, surgery becomes necessary.

Conditions that may lead to this include

• Chronic inflammatory diseases
• Degenerative bone disorders
• Severe hip dysplasia affecting the femoral head

Bipolar hemiarthroplasty provides reliable pain reduction and helps restore movement.

7. Age-Related Degeneration :- With aging, the hip joint undergoes natural wear and tear. In people above 70, the femoral head loses its resilience, and the cartilage becomes thinner.
   When degeneration progresses to the point where the femoral head can no longer function normally, hemiarthroplasty becomes a practical and effective option.

Benefits for elderly patients include

• Reduced dislocation risk
• Faster recovery
• Lower surgical stress than total replacement

This makes bipolar hemiarthroplasty a preferred choice in geriatric orthopedics.

Conclusion

Bipolar hemiarthroplasty surgery is most commonly performed due to femoral neck fractures in elderly patients, but several other conditions like avascular necrosis, arthritis, bone tumors, and failed previous surgeries can also necessitate this procedure. Understanding these causes helps patients and caregivers prepare for surgery, choose the right treatment plan, and set realistic expectations for recovery.

With modern surgical techniques and advanced implant designs, bipolar hemiarthroplasty offers excellent pain relief, stability, and improved mobility for patients suffering from severe hip damage. Early diagnosis and timely surgical intervention can greatly enhance long-term results and reduce complications.