Posterior Hip Precautions: Understanding Post-Surgical Restrictions and Daily Living Adjustments

What are posterior hip precautions?

Posterior hip precautions are a set of specific movement restrictions prescribed following a total hip replacement (arthroplasty) performed via a posterior or posterolateral surgical approach, designed to prevent the new hip joint from dislocating.

Introduction to Hip Precautions

Following a total hip replacement (THA), the new joint, consisting of a femoral head (ball) and an acetabular cup (socket), is initially vulnerable to dislocation. To protect the healing joint capsule and surrounding soft tissues, surgeons and physical therapists prescribe specific movement restrictions known as hip precautions. These precautions are tailored to the surgical approach used, as different approaches compromise different sets of muscles and joint capsule structures.

Why Posterior Hip Precautions?

The posterior or posterolateral surgical approach is one of the most common methods for total hip arthroplasty. This approach involves accessing the hip joint by incising or splitting muscles such as the gluteus maximus and the short external rotators (e.g., piriformis, obturator internus), and incising the posterior joint capsule. While this approach offers excellent visualization of the joint, it temporarily weakens the posterior stabilizing structures of the hip. Consequently, movements that push the femoral head posteriorly out of the acetabulum are restricted to prevent dislocation.

The Specific Posterior Hip Precautions

The primary goal of posterior hip precautions is to avoid movements that create a leverage effect, pushing the femoral head posteriorly out of its socket. The three cardinal rules are:

• No Hip Flexion Past 90 Degrees:

  • Explanation: Bending the hip beyond a right angle (90 degrees) significantly increases the mechanical leverage that can force the femoral head posteriorly. This is especially true when combined with other restricted movements.
  • Practical Avoidance: Do not bend forward excessively at the waist, avoid sitting in low chairs or on low toilets, and do not pull your knees up towards your chest.

• No Hip Adduction Past Midline:

  • Explanation: Adduction (bringing the leg across the body's midline) can create a lever against the posterior aspect of the joint, particularly when combined with flexion or internal rotation.
  • Practical Avoidance: Do not cross your legs (at the knees or ankles), and avoid letting your affected leg swing inward. When lying on your side (only if permitted by your surgeon), always place a pillow between your knees.

• No Hip Internal Rotation:

  • Explanation: Internally rotating the hip (pointing your toes inward) twists the femoral head within the socket, potentially forcing it posteriorly through the weakened capsule and soft tissues.
  • Practical Avoidance: Avoid pivoting on the operated leg, do not turn your toes inward, and be mindful of your foot position when turning or changing direction.

Practical Application in Daily Living

Adhering to posterior hip precautions requires conscious effort and modifications to everyday activities. Here's how they translate into practical advice:

• Sitting:
  • Use chairs with firm seats and armrests that allow you to keep your hips higher than your knees.
  • Avoid low couches, recliners, and soft chairs.
  • When sitting, slide your operated leg slightly forward to maintain hip angle.
• Sleeping:
  • Initially, most surgeons recommend sleeping on your back.
  • If permitted to sleep on your side, always lie on the non-operated side with two or more pillows placed between your knees to prevent adduction.
• Toileting:
  • Use a raised toilet seat to prevent excessive hip flexion.
• Bending and Reaching:
  • Avoid bending over to pick up objects from the floor. Use long-handled grabbers or ask for assistance.
  • Do not reach down to tie shoes or pull up socks; use assistive devices like long-handled shoehorns or sock aids.
• Transfers (Getting In/Out of Bed or Car):
  • Bed: Scoot to the edge of the bed, swing both legs out together while keeping your torso upright. Reverse the process to get into bed.
  • Car: Back up to the seat, extend the operated leg forward, and sit down slowly. Use your arms to help pivot your body and swing both legs into the car simultaneously. Recline the seat slightly to prevent excessive hip flexion.
• Dressing:
  • Dress the operated leg first, using assistive devices if needed. Undress the operated leg last.

Importance of Adherence

Strict adherence to posterior hip precautions is crucial for a successful recovery and to prevent complications. Dislocation of a total hip replacement is a painful event that often requires an emergency procedure (closed reduction) to put the joint back in place, or even revision surgery in severe or recurrent cases. Non-compliance can prolong rehabilitation, increase healthcare costs, and negatively impact the long-term success of the hip replacement.

Duration of Precautions

The duration for which posterior hip precautions must be followed varies. Traditionally, they were enforced for 6 to 12 weeks, allowing time for the joint capsule and surrounding soft tissues to heal and strengthen. However, advancements in surgical techniques (e.g., tissue-sparing approaches, enhanced capsular repair) and implant designs have led some surgeons to adopt modified or even "precaution-less" protocols, especially for younger, healthier patients. It is imperative to follow your specific surgeon's and physical therapist's guidelines, as they will be tailored to your individual surgery and recovery progress.

Rehabilitation and Progression

Physical therapy plays a vital role in recovery, guiding patients through a structured exercise program designed to strengthen the muscles around the hip while strictly respecting the precautions. As healing progresses, the therapist will gradually introduce exercises to improve range of motion, strength, and functional mobility, eventually preparing the patient for a return to daily activities and, for some, recreational sports.

When to Seek Medical Advice

Contact your surgeon or medical team immediately if you experience any of the following:

• Sudden, severe pain in your hip or groin.
• A "pop" or "clunk" sensation in your hip.
• Inability to bear weight on your operated leg.
• Noticeable shortening or rotation of your operated leg.

Conclusion

Posterior hip precautions are a fundamental component of post-operative care following a total hip replacement via a posterior approach. By understanding the biomechanical principles behind these restrictions and diligently applying them to daily activities, patients can significantly reduce the risk of dislocation, ensuring a safer and more successful recovery journey towards improved mobility and quality of life. Always prioritize clear communication with your surgical team and physical therapist regarding your specific post-operative instructions.