Total Knee Replacement: Suture Selection, Types, and Post-Operative Recovery

What suture is used in total knee replacement?

The selection of suture material in total knee replacement (TKR) is not limited to a single type but is a nuanced process involving various materials chosen strategically by the orthopedic surgeon based on the specific tissue layer being closed, its biomechanical demands, and the desired healing profile.

Understanding Surgical Sutures in Orthopedic Surgery

Surgical sutures are fundamental tools in any operative procedure, designed to approximate tissues, provide mechanical support during the healing process, and facilitate wound closure. In orthopedic surgery, particularly complex procedures like Total Knee Replacement (TKR), the choice of suture material is critical, directly influencing the stability of the surgical site, the risk of complications, and the patient's recovery trajectory.

Sutures are broadly categorized into:

• Absorbable Sutures: These materials are designed to degrade and be absorbed by the body over time, losing their tensile strength as they do. They provide temporary support and are useful in tissues that heal relatively quickly or where long-term foreign material presence is undesirable.
• Non-Absorbable Sutures: These materials retain their tensile strength indefinitely and remain in the body permanently (unless removed). They are used when long-term tissue approximation or permanent strength is required, such as in tendon repairs or certain fascial closures.

The ideal suture material for a given application must possess adequate tensile strength, be easy to handle, elicit minimal tissue reaction, and resist infection.

Key Considerations for Suture Selection in Total Knee Replacement (TKR)

A TKR involves incising and subsequently closing multiple distinct tissue layers, each with unique healing characteristics and mechanical requirements. The surgeon's choice of suture material for each layer is meticulously planned:

• Tissue Layers and Their Demands:
  • Joint Capsule/Synovium: Requires a suture that provides initial stability but may not need permanent strength as the surrounding tissues heal.
  • Muscle and Fascia: These layers are crucial for structural integrity and functional recovery. They require strong, often long-lasting, support to withstand the stresses of knee movement.
  • Subcutaneous Tissue: Primarily for dead space obliteration and superficial tissue approximation. Absorbable sutures are typically preferred here.
  • Skin: Requires fine sutures for cosmetic closure and to prevent infection, typically removed after healing.
• Mechanical Stress: The knee joint is subject to significant forces during daily activities. The sutures used must withstand these stresses without premature failure.
• Healing Time: Different tissues heal at different rates. The suture's degradation profile (for absorbable types) must align with the tissue's healing timeline.
• Infection Risk: Some suture materials are less prone to bacterial adherence than others. Monofilament sutures, for example, have a smoother surface than braided sutures, potentially reducing the risk of bacterial colonization.
• Surgeon Preference and Patient Factors: Experience, training, and specific patient characteristics (e.g., healing capacity, presence of comorbidities) also influence suture selection.

Common Suture Types Utilized in TKR

Given the multi-layered nature of TKR closure, a combination of suture types is typically employed:

• Absorbable Sutures: These are widely used for deeper layers where temporary support is sufficient.

  • Polyglactin 910 (Vicryl): A braided synthetic absorbable suture, commonly used for joint capsule, subcutaneous tissue, and sometimes fascia. It maintains strength for several weeks.
  • Polydioxanone (PDS): A monofilament synthetic absorbable suture known for its prolonged strength retention, making it suitable for slower-healing tissues like fascia or joint capsule where extended support is desired.
  • Poliglecaprone 25 (Monocryl): A monofilament synthetic absorbable suture with rapid absorption, often used for subcutaneous closures and skin where a short-term hold is needed.
  • Polyglycolic Acid (PGA): Another braided synthetic absorbable suture, similar to Vicryl, used for general soft tissue approximation.

• Non-Absorbable Sutures: These are reserved for areas requiring permanent or very long-term strength.

  • Polypropylene (Prolene): A monofilament synthetic non-absorbable suture known for its smooth passage through tissue and minimal tissue reactivity. It's often used for fascial closure in areas of high tension or for securing tendons.
  • Polyester (Ethibond, Ticron): Braided synthetic non-absorbable sutures offering high tensile strength. They are commonly used for securing tendons or ligaments, or for robust fascial closures.
  • Nylon: A monofilament non-absorbable suture, sometimes used for skin closure due to its smooth surface and minimal tissue drag.
  • Stainless Steel Wire: In rare cases, for extremely high-tension areas or revisions, a stainless steel wire may be used for bone or tendon repair, though less common for routine soft tissue closure in TKR.

For skin closure, surgeons may use fine absorbable sutures placed subcuticularly (under the skin) to avoid visible stitches, or non-absorbable sutures (nylon or polypropylene) that are removed post-operatively, or even surgical staples.

The Role of Suture in Post-Operative Recovery

The meticulous closure of the surgical wound using appropriate suture materials is paramount for optimal post-operative recovery. Proper suturing:

• Ensures Wound Integrity: Prevents dehiscence (wound opening) and provides a stable environment for healing.
• Minimizes Infection Risk: A well-approximated wound reduces dead space, preventing fluid accumulation that can serve as a breeding ground for bacteria.
• Facilitates Early Mobilization: A strong, stable closure allows for earlier initiation of rehabilitation exercises, which is crucial for restoring knee range of motion and strength.
• Optimizes Aesthetic Outcome: Careful skin closure techniques contribute to a less noticeable scar.

Patients are typically advised on incision care, including keeping the wound clean and dry, monitoring for signs of infection, and adhering to activity restrictions to protect the healing tissues.

Conclusion: A Multifaceted Approach to Closure

In summary, there isn't one single "suture" used in a total knee replacement. Instead, orthopedic surgeons employ a sophisticated, layered approach, selecting a variety of absorbable and non-absorbable suture materials, each chosen for its specific properties and suitability for the distinct anatomical structures being repaired. This strategic selection ensures optimal tissue approximation, provides robust mechanical support during the critical healing phase, and ultimately contributes significantly to the long-term success and functional outcome of the total knee replacement. The surgeon's expertise in this detailed aspect of the procedure is as critical as the implant selection itself, underscoring the comprehensive nature of modern orthopedic surgery.