Muscle sparing hip and knee replacement refers to surgical techniques that reach the joint without cutting through major muscles or tendons. Instead of splitting muscle, I work between natural tissue planes or slide underneath the muscle to reach the joint. The implants are the same as in traditional surgery; what changes is the route in and the amount of soft tissue disruption along the way.
I am Dr. Cory Calendine, a board-certified orthopaedic surgeon practising in Franklin, Tennessee. In my practice at the Bone and Joint Institute of Tennessee, the two muscle sparing techniques I use most often are the direct anterior approach for total hip replacement and the subvastus approach for total knee replacement.
The short video below walks through what muscle sparing surgery actually changes beneath the skin and why it can shorten early recovery.
What Is Muscle Sparing Hip and Knee Replacement?
Patients ask me about incision size at almost every consultation. It is a fair question, but the more important question is what happens beneath the skin. A small incision over a poorly executed surgery does not help anyone. A well planned muscle sparing approach, with proper exposure, can give patients a meaningful head start on recovery.
The goal is not the smallest possible scar. The goal is to protect the muscles and tendons that power your joint while still placing the implant accurately. When those two things come together, recovery tends to be smoother in the first weeks.
How Big Is the Incision in Traditional Hip and Knee Replacement?
Traditional joint replacement has well established incision lengths. Understanding the baseline helps put muscle sparing options in context.
Traditional Total Knee Replacement
Traditional total knee replacement typically uses a 7 to 10 inch vertical incision down the front of the knee. The surgeon uses a medial parapatellar approach, which runs alongside the kneecap and then cuts up into the quadriceps tendon. That split gives wide exposure, but it also creates a tendon repair that has to heal afterward.
Traditional Total Hip Replacement
Traditional total hip replacement uses a 10 to 12 inch incision, usually on the side or back of the hip. The surgeon either splits or detaches muscles and tendons to dislocate the hip and expose the joint. The posterior approach divides the external rotators; the lateral approach detaches portions of the gluteus medius and minimus from the greater trochanter.
Both traditional approaches have decades of excellent outcomes behind them, and they remain the right choice for many patients. The question is whether less tissue disruption is possible without sacrificing exposure or implant positioning.
Muscle Sparing Hip and Knee Replacement Options
Muscle sparing techniques use different deep dissection to protect the muscles around the joint. The implants are the same as in traditional surgery. What changes is the route to the joint.
Subvastus Approach for Knee Replacement
The subvastus approach is a true muscle sparing technique for total knee replacement. Instead of splitting the quadriceps tendon, I slide underneath the vastus medialis muscle and lift the entire quadriceps group off the femur as one unit. After placing the implants, the muscle settles back into its natural position.
The skin incision is similar in length to traditional knee replacement, sometimes slightly shorter. The real difference is below the skin. Because the quadriceps tendon stays intact, patients tend to have less pain with knee bending in the early period. Most of my subvastus patients are walking the same day as surgery, often progressing off a walker within a week.
I combine the subvastus approach with robotic assistance for nearly all my primary knee replacements. The robotic platform adds precision in bone cuts and implant positioning, while the subvastus approach protects the soft tissue around the knee.
Direct Anterior Approach for Hip Replacement
The direct anterior approach is the muscle sparing option for total hip replacement. The incision is made on the front of the hip and typically measures 3 to 6 inches. I work between the sartorius and tensor fascia lata muscles, then between the rectus femoris and gluteus medius. No major muscles or tendons are cut or detached.
Patients often achieve full weight bearing on the day of surgery. Because the muscles around the hip stay intact, the risk of dislocation is very low. Published series of more than 1,000 patients report dislocation rates well below 1 percent with the anterior approach.
The direct anterior approach does require a specialised operating table and intraoperative imaging for accurate implant positioning. There is also a learning curve, which is why surgeon experience matters significantly with this technique.
How Long Is the Incision in Muscle Sparing Joint Replacement?
Incision length in muscle sparing hip and knee replacement varies with patient anatomy, body type, and the complexity of the joint problem.
For direct anterior hip replacement, the typical incision is 3 to 6 inches. For subvastus knee replacement, the skin incision is usually 4 to 7 inches, similar to or slightly shorter than traditional knee replacement.
Patient height and body type matter. Research on knee replacement incision length has shown that incision size correlates more strongly with patient height than with weight or body mass index. Taller patients generally need slightly longer incisions for adequate exposure, regardless of approach.
A smaller scar can be a cosmetic advantage, but I never compromise exposure for cosmesis. Proper implant alignment and balance are what determine how well the joint functions over decades. The incision needs to be long enough to do the job correctly.
Who Is a Candidate for Muscle Sparing Hip and Knee Replacement?
Not every patient is an ideal candidate for muscle sparing techniques. During your consultation, I weigh several factors to determine the right approach for you.
Patients who tend to do well with muscle sparing approaches include:
- Adults with end stage hip or knee arthritis who have not responded to non-surgical care
- Patients with relatively normal joint anatomy and alignment
- Those motivated to participate actively in rehabilitation
- Patients without significant prior surgery on the affected joint
Some situations make muscle sparing techniques more challenging or less appropriate:
- Severe joint deformity or stiffness
- Significant prior surgery with hardware in place
- Very high body mass index, which can limit exposure
- Certain anatomical variations that increase complication risk
For knee replacement specifically, patients with very stiff knees or major deformity sometimes need a traditional medial parapatellar approach for safe exposure. For hip replacement, very muscular patients or those with unusual femoral anatomy may do better with a posterior or lateral approach.
The decision is individualised. During your consultation in our Franklin, Tennessee office, we review your X-rays, examine your joint, and discuss which approach gives you the best combination of safety, recovery, and long term function.
What Is Recovery Like After Muscle Sparing Joint Replacement?
Recovery after muscle sparing hip and knee replacement is generally faster than traditional surgery, particularly in the first six weeks.
After direct anterior hip replacement, most patients walk with a walker or cane the day of surgery and transition off assistive devices within two to four weeks. There are typically no positional restrictions, which means patients can sit, sleep, and bend normally from the start.
After subvastus knee replacement, most patients also walk the same day. Active knee bending is often easier in the first week because the quadriceps tendon is intact. Physical therapy starts on day one and usually continues for six weeks.
Long term outcomes after muscle sparing techniques match those of traditional approaches when surgery is performed well. The implants are the same, and durability depends mainly on implant positioning, patient activity, and body weight rather than on the surgical approach.
Risks remain similar to any joint replacement and include infection, blood clots, nerve injury, fracture, and the possibility of needing revision surgery in the future. Muscle sparing techniques do not eliminate these risks, but they may reduce soft tissue trauma and shorten the early recovery period.
How Do I Choose the Right Surgeon for Muscle Sparing Joint Replacement?
Surgeon experience matters more than the specific approach. A surgeon highly experienced in traditional knee replacement may achieve better results for you than a less experienced surgeon attempting a muscle sparing technique for the first time.
Questions worth asking your orthopaedic surgeon:
- Are you board certified and fellowship trained in joint replacement?
- How many hip or knee replacements do you perform each year?
- What approach do you recommend for my specific situation, and why?
- How many muscle sparing procedures have you performed?
- What are your published outcomes for infection, dislocation, and revision?
In my own practice, I perform a high volume of hip and knee replacements each year, and the muscle sparing approaches I use are techniques I have refined through years of training and operative experience. I combine these approaches with robotic precision when appropriate.
Conclusion: Matching the Right Approach to Your Anatomy
Muscle sparing hip and knee replacement is not about the smallest scar; it is about protecting the muscles and tendons that move your joint while placing the implant accurately. The direct anterior approach spares the muscles around the hip, and the subvastus approach protects the quadriceps tendon at the knee, so many patients walk sooner and recover faster in the first weeks.
Both approaches reach the same long term goal as traditional surgery: a stable, well aligned, durable joint. After more than 20 years and over 700 hip and knee replacements each year, I have found that the best results come from matching the right approach to your anatomy, not from chasing any single technique.
Take the Next Step
If you have hip or knee arthritis that has not improved with non-surgical care, the right surgical approach depends on your specific anatomy, activity goals, and overall health. A thorough evaluation is the only way to know whether muscle sparing hip or knee replacement is right for you.
For a consultation with Dr. Cory Calendine at the Bone and Joint Institute of Tennessee, 3000 Edward Curd Lane, Franklin, TN 37067, serving patients across Brentwood, Nashville, and Middle Tennessee, you can schedule a consultation or call (615) 791-2630. No referral is required.
This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified orthopaedic surgeon before making decisions about joint replacement. Individual results vary based on personal health circumstances.
References
- American Academy of Orthopaedic Surgeons. Total knee replacement. OrthoInfo (AAOS). 2023. Available at: orthoinfo.aaos.org
- American Academy of Orthopaedic Surgeons. Minimally invasive total hip replacement. OrthoInfo (AAOS). 2022. Available at: orthoinfo.aaos.org
- Higgins BT, Barlow DR, Heagerty NE, et al. Anterior versus posterior approach for total hip arthroplasty: a meta-analysis. J Arthroplasty. 2015;30(3):419-434.
- Berstock JR, Blom AW, Beswick AD. A systematic review and meta-analysis of the subvastus versus medial parapatellar approach in total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2018;26(8):2284-2291.
