As every coder knows, the hip, one of the largest joints in the body, is a ball and socket joint. Looking at the hip’s anatomy, the “socket” portion is formed by the acetabulum, and the “ball” is the upper end of the femur. The bony surfaces of the hip are covered by articular cartilage that cushions the bones, permitting easy movement. The synovial membrane surrounding the joint produces a small amount of fluid that lubricates the joint and ligaments that connect the ball to the socket and provides stability.

The hip joint, like all body parts, can experience pain. The most common causes of hip pain include:

• Arthritis
  • Osteoarthritis
  • Rheumatoid arthritis
  • Post-traumatic arthritis
• Osteonecrosis
• Childhood hip disease (can cause pain/arthritis later in life even if successfully treated in childhood)
• Bursitis
• Tendinitis
• Trauma
• Tumor
• Other

Depending on the diagnosis, the first step in treating hip pain is usually medical. Such treatment can include oral meds like acetaminophen, ibuprofen, etc. It can also include PT, injections, rest, ICE, and the like.

Again, depending on the diagnosis, hip pain that doesn’t respond medical treatment may necessitate hip replacement, AKA arthroplasty. At present, there are three choices when considering hip arthroplasty:

• Total – both ball and socket replacement
• Partial – only the ball is replaced (most common in older patients with a hip fracture)
• Resurfacing the femoral head and socket (usually reserved for younger, active patients).

There are three common ways to access the hip joint during surgery:

• Anterior (from the front)
• Lateral (from the side)
• Posterior (from the back)

In addition to the method of accessing the hip, the procedure itself can be either “traditional,” or “minimally invasive.”

• Minimally invasive – The goal is to impact the healthy tissue (muscle/blood vessels) as little as possible. The joint is accessed via moving the muscles as opposed to cutting them. Not all patients are candidates for minimally invasive procedures.
• Traditional replacement – A single, large incision is made to access the joint, usually through the lateral or posterior approaches. Recovery is usually longer because the muscles/tendons are cut or detached, and then repaired after joint is replaced. Post-op dislocations are a risk until all supportive structures are healed.

Hip prostheses have 2 parts:

• The femora head, or ball, is attached to metal stem, which is inserted into the femur for stability.
• The acetabulum, the layer “attached” to the socket, which allows smooth rotation of the prosthesis.

The prosthesis may either be cemented or it can be uncemented, which means the prosthesis is attached with a porous surface that allows bone to grow over time, holding it in place

Assigning diagnoses and procedure codes will obviously depend on the exact reason for the replacement as well as the actual procedure performed. While it is stating the obvious, coders should thoroughly read the H&P and procedure report in order to accurately assign ICD-10-CM/PCS codes.

Please see accompanying charts with examples.

Hip Arthroplasty Coding Examples

For the sake of expediency, operative reports were abstracted to provide the above examples. Only diagnoses related to the arthroplasties were included.

REFERENCES:

• https://orthoinfo.aaos.org/en/treatment/total-hip-replacement/
• https://www.hss.edu/conditions_anterior-hip-replacement-overview.asp
• https://www.hss.edu/condition-list_hip-replacement.asp
• https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/hip-replacement-surgery#:~:text=Your%20doctor%20may%20recommend%20hip,Osteonecrosis%20(avascular%20necrosis)