ARTHROPLASTY

(Hip and Knee)

Arthroplasty is a subspecialty of orthopedic surgery that focuses on restoring joint function through joint replacements. These subspecialist surgeons perform primarily hip and knee arthroplasties, both primary replacements and revision surgeries. Arthroplasties are among the most transformative procedures with the highest patient satisfaction rates, addressing debilitating conditions such as osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis.

Osteoarthritis

(Hip and Knee)

Osteoarthritis is the most common reason for undergoing arthroplasty, and is one of the most common conditions seen in the orthopedic clinic. It is thus an incredibly high-yield topic in medical school on your orthopedic rotation. It is important to understand what questions to ask on history, relevant parts of a physical exam, findings on radiograph, and management options, both operative and non-operative.

 Osteoarthritis is a degenerative joint disease characterized by progressive wear of articular cartilage, typically in weight-bearing joints such as the hips and knees.

Explore detailed vignettes to enhance your practice: dive into Hip Arthroplasty and Knee Arthroplasty

  • Patients experience gradual aching pain in the groin/buttock or knee over months to years. Pain is worse with activity and weightbearing and improves with rest. Some patients can experience decreased range of motion, joint instability, locking, catching, or swelling. You can also ask about history of autoimmune diseases and symptoms, including joint pain elsewhere, to rule out rheumatoid arthritis.

  • Gait: Assess for antalgic gait or Trendelenberg gait secondary to abductor weakness

    Palpation: Palpate all bony prominences and specific soft tissue structures (i.e. bursa to rule out bursitis)

    Range of motion: Assess range of motion of hip and knee in all planes. Assess for asymmetry

    Special tests:

    • Hip: leg length, FABER (Flexion, Abduction, External Rotation) test, FADIR (Flexion, Adduction, Internal rotation) test, Thomas test, Ober test

    • Knee: varus/valgus stress tests, patellar tracking

  • Radiograph: Features of osteoarthritis include joint space narrowing, osteophytes, subchondral sclerosis and cysts (LOSS mnemonic: Loss of joint space, Osteophytes, Subchondral sclerosis, Subcondral cysts). Findings on radiograph are a common question asked by preceptors!

    • Knee: weightbearing AP, lateral, skyline views

    • Hip: standing AP pelvis and lateral hip views

  • Non-operative:

    • NSAIDs for analgesia

    • Physiotherapy

    • Joint injections: corticosteroid, visco-elastic

    Operative:

    • Total joint arthroplasty

    • Partial joint arthroplasty

      • Unicompartmental knee arthroplasty

      • Patellofemoral resurfacing

      • Hip resurfacing

    Peri-articular osteotomies to correct knee alignment or hip coverage

    • High tibial osteotomy

    • Periacetabular osteotomy

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Hip

Knee

 

SURGICAL STEPS

It is beneficial to know the general surgical steps to expect when you are in the operating room. This will help you understand what is going on, anticipate how to help, prepare for questions asked of you, and to also ask intelligent questions to your preceptor.

Hip

For Hip Arthroplasty, review the steps of the procedure from:

  1. Positioning

  2. Draping

  3. Surgical approach             

  4. Removal of femoral head

  5. Preparation and placement of acetabulum component

  6. Hip dislocation and preparation for femoral stem component

  7. Insertion and placement of femoral stem component

  8. Assembly of prosthesis

  9. Hip reduction and trialing

  10. Final implants (+/- cementing)

  11. Closure

For those with more interest in orthopedics, specific parts of the surgical procedure to review as you may be asked questions about them, or are good questions to discuss with your preceptor are:

  • How does the surgeon template? What are the options for implants: cup, stem and neck, and head

  • How to assess appropriate acetabular cup placement: version, depth

  • How to assess appropriate femoral stem placement: version, offset, and leg length

  • Cemented vs. uncemented implants

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Knee

For Knee Arthroplasty, review the steps of the procedure from:

  1. Positioning

  2. Draping

  3. Surgical approach

  4. Arthrotomy

  5. Femoral cuts

  6. Tibial cuts

  7. Balancing and placement of trial components

  8. Patella preparation and resurfacing

  9. Trialing and final implants (+/- cementing)

  10. Closure

 

For those with more interest in orthopedics, more advanced topics for TKA to read up on and discuss with your preceptor are:

  • How does the surgeon template?

  • What is balancing: flexion and extension gaps

  • What is constraint: cruciate-retaining, posterior-stabilizing, etc.

  • Cemented vs. uncemented implants

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OUTCOMES

Arthroplasty is an incredibly rewarding field with high rates of patient satisfaction. Often times, patients can be weight-bearing on the day of surgery and some can be discharged on this same day. Within months, patients can return to their activities and sports.

However, there are also risks and complications with arthroplasty. The major complications are prosthetic joint infections, peri-prosthetic fractures, dislocations, and damage to nearby structures. These are important topics to review especially for clinic days. These are also topics you can discuss with your preceptor.

Resources