Hemi (Half) Knee Replacement
A surgical procedure to replace the damaged portion of the knee while preserving healthy tissue
Unlike total knee replacement, which involves replacing the entire knee joint, a hemi knee replacement focuses on repairing damage in a single compartment of the knee. This procedure is typically recommended for patients with arthritis or degenerative conditions affecting only one part of the knee, such as the medial (inner) or lateral (outer) compartment.
- Common Reasons for Hemi Knee Replacement Surgery
- How to prepare for a Half Knee Replacement
- What Happens during the Hemi Arthroplasty Surgical Procedure
- Potential Risk with Half Knee Replacement Surgery
- What to Expect After Half Knee Replacement Surgery
- Hemi Arthroplasty Rehabilitation and Recovery
- Long-Term Outcomes following Hemi Arthroplasty
Common Reasons for Hemi Knee Replacement Surgery
- Osteoarthritis confined to one compartment of the knee.
- Persistent knee pain and stiffness that does not respond to non-surgical treatments.
- Limited but stable knee joint alignment and ligaments.
- Desire to retain as much of the natural knee as possible.
The primary goals of hemi knee replacement are to reduce pain, improve mobility, and restore function while preserving healthy tissue and enabling faster recovery.
How to prepare for a Half Knee Replacement
Dr Ben McGrath will conduct a thorough evaluation, including a detailed medical history, physical examination, and imaging studies (e.g., X-rays, MRIs, or CT scans) to confirm the suitability of hemi knee replacement and plan the procedure.
Key Steps in Preparation:
- Consultation: Dr McGrath will explain the procedure, outline the risks and benefits, and answer any questions you may have.
- Pre-Surgical Instructions: Patients may be required to fast before surgery and adjust medications, such as stopping blood thinners.
- Prehabilitation: Strengthening the muscles around the knee can optimise recovery.
- Lifestyle Adjustments: Maintaining a healthy weight, ceasing smoking, and managing underlying conditions like diabetes can improve surgical outcomes.
What Happens during the Hemi Arthroplasty Surgical Procedure
Hemi knee replacement is performed under regional or general anaesthesia and typically involves a minimally invasive approach to reduce recovery time.
Surgical Steps:
- Incisions: A small incision is made over the knee to access the damaged compartment.
- Preparation of the Joint: The damaged cartilage and bone are removed while preserving the surrounding healthy tissue.
- Placement of Implants: A prosthetic component, often made of metal and plastic, is fitted to replace the damaged surfaces. These implants are secured with bone cement or press-fit techniques.
- Alignment and Stability Check: The surgeon ensures proper alignment and smooth movement of the knee joint.
- Closure: The incision is closed with sutures or adhesive strips, and the knee is bandaged for protection.
The procedure typically takes 1 to 2 hours, depending on the complexity.
Potential Risk with Half Knee Replacement Surgery
As with any surgery, hemi knee replacement carries potential risks:
- Infection: At the surgical site or within the joint.
- Blood Clots: Rare but possible in the legs.
- Implant Issues: Loosening, wear, or failure over time.
- Residual Pain or Stiffness: Some patients may continue to experience mild discomfort.
- Nerve or Vessel Injury: Extremely rare but a potential complication.
Dr McGrath employs advanced techniques and follows strict protocols to minimise these risks.
What to Expect After Half Knee Replacement Surgery
Immediate Post-Operative Care:
- Pain Management: Discomfort and swelling can be managed with prescribed medications and regular icing.
- Assistive Devices: Patients may use crutches or a walker for initial mobility support.
- Discharge Instructions: Guidance will be provided on wound care, physical activity, and follow-up appointments.
Hemi Arthroplasty Rehabilitation and Recovery
A structured rehabilitation program tailored to individual needs is critical for achieving the best outcomes.
Phase 1: Early Recovery (Weeks 0–6)
- Goals: Reduce swelling, protect the joint, and regain mobility.
- Activities: Partial weight-bearing with assistive devices, range-of-motion exercises, and cryotherapy.
Phase 2: Strength and Function (Weeks 6–12)
- Goals: Improve muscle strength and restore functional movement.
- Activities: Physiotherapy exercises, light cycling, and progressive weight-bearing.
Phase 3: Return to Activity (Months 3–6)
- Goals: Safely resume daily activities and low-impact sports.
- Activities: Strength training, balance exercises, and functional drills under professional supervision.
Long-Term Outcomes Following Hemi Arthroplasty
Hemi knee replacement may provide significant improvements in pain relief, mobility, and quality of life. Long-term success depends on:
- Regular follow-up appointments to monitor progress.
- Adherence to the rehabilitation program.
- Maintaining a healthy lifestyle to minimise stress on the joint.
The lifespan of the prosthetic components can vary, with many lasting 10 to 15 years or longer with appropriate care.