UNDERSTANDING THE KNEE JOINT: THREE COMPARTMENTS
The knee is not a single joint surface. It is made up of three distinct joint compartments:
- Medial compartment – The inside of the knee
- Lateral compartment – The outside of the knee
- Patellofemoral compartment – The joint between the kneecap and the end of the thighbone
In some patients, osteoarthritis affects only one of these three compartments, while the cartilage in the remaining compartments-along with the ligaments, muscles, and tendons-remains healthy and functional.
When arthritis is confined to a single compartment, it may be possible to treat only the damaged joint surface of that compartment, rather than replacing the entire knee.
WHAT IS PURE MOTION PARTIAL KNEE RESURFACINGSM?
Pure Motion Partial Knee Resurfacing-also called partial knee replacement-focuses on resurfacing only one of the knee’s three joint compartments while preserving the healthy portions of the knee.
Rather than replacing the entire knee joint, this procedure replaces only the worn cartilage surfaces within the affected compartment, leaving the joint surfaces of the remaining compartments, along with the ligaments, muscles, and tendons, intact.
Pure Motion Partial Knee ResurfacingSM is Dr. W. Gaines Cumbie’s refined approach to treating single-compartment knee arthritis and is defined by two required principles that are applied in every case:
- A complete muscle- and tendon-sparing surgical approach
- Patient-specific implant positioning designed to restore the knee’s pre-arthritic joint line, axis of rotation, and limb alignment
The difference between Pure Motion Partial Knee ResurfacingSM and Pure Motion Total Knee Replacement is how much of the knee requires treatment-not the philosophy or execution of the surgery.
Together, these principles are designed to restore knee motion that more closely resembles how the knee moved before osteoarthritis caused pain, stiffness, and loss of function.
PRINCIPLE #1: COMPLETE MUSCLE AND TENDON SPARING PARTIAL KNEE SURGERY
In Pure Motion Partial Knee ResurfacingSM, the quadriceps muscle and tendon are left completely intact during surgical exposure.
Rather than cutting the quadriceps tendon, the muscle and tendon are gently mobilized to the side, preserving the knee’s extensor mechanism. This supports early strength, stability, and confidence with movement after surgery.
Why patients often appreciate this muscle-sparing approach:
- Preservation of quadriceps strength supports earlier functional recovery
- Reduced irritation of the extensor mechanism may lead to less early pain and stiffness
- Greater confidence with walking, physical therapy, and daily activities
- A smoother, more comfortable early recovery experience
PRINCIPLE #2: RESTORING THE PRE-ARTHRITIC JOINT LINE, AXIS OF ROTATION, AND LIMB ALIGNMENT
Pure Motion Partial Knee ResurfacingSM requires patient-specific implant positioning designed to restore the knee’s original joint line, axis of rotation, and limb alignment-the way the knee was oriented before arthritis developed.
Even in partial knee surgery, restoring native anatomy matters. The preserved compartments, ligaments, muscles, and tendons all function based on the knee’s original orientation. When the joint line or alignment is altered, these structures may not function as they did prior to arthritis.
The Pure Motion philosophy focuses on recreating each patient’s native knee anatomy. By restoring the pre-arthritic joint line and limb alignment, the resurfaced knee is designed to move in a way that feels more natural-allowing preserved ligaments and muscles to function as they did before cartilage wear caused pain, stiffness, and restricted motion.
WHY PARTIAL KNEE RESURFACING CAN BE AN ADVANTAGE FOR THE RIGHT PATIENT
When arthritis affects only one compartment of the knee, much of the joint often remains healthy.
Pure Motion Partial Knee ResurfacingSM is designed to take advantage of this by:
- Preserving the two healthy knee compartments
- Maintaining native ligaments, including the ACL and PCL when intact
- Preserving normal knee motion pathways
- Restoring the knee’s natural joint line, axis of rotation, and alignment
Because more of the knee’s native structure is preserved, many patients report that partial knee resurfacing feels more natural during walking, stair climbing, and daily activities.
WHO IS A CANDIDATE FOR PURE MOTION PARTIAL KNEE RESURFACINGSM?
Partial knee resurfacing is not appropriate for everyone. It is typically considered when:
- Arthritis is confined to a single knee compartment
- The remaining compartments have healthy cartilage
- Key ligaments are intact and functioning normally
- Knee motion and stability are preserved
- Deformity and stiffness are within an acceptable range
Patients with arthritis affecting multiple compartments may be better served by total knee replacement. Determining candidacy requires careful evaluation of imaging, alignment, ligament integrity, and overall knee mechanics.
PARTIAL KNEE RESURFACING VS. TOTAL KNEE REPLACEMENT
For patients who are appropriate candidates, partial knee resurfacing may offer meaningful benefits:
- Less bone removal
- Preservation of healthy cartilage, bone, and ligaments
- Faster early recovery for many patients
- A knee that often feels more natural because much of it remains unchanged
Pure Motion Total Knee Replacement remains an excellent and durable solution when arthritis is more widespread. If arthritis progresses over time after partial knee resurfacing, conversion to total knee replacement remains an option.
WHY COMBINING BOTH PURE MOTION PRINCIPLES MATTERS IN PARTIAL KNEE SURGERY
Scientific evidence supports each Pure Motion principle individually:
- Muscle-sparing exposure supports earlier functional recovery
- Restoring the native joint line and alignment supports more natural knee mechanics
Pure Motion Partial Knee ResurfacingSM combines both into one consistent philosophy-preserving the quadriceps mechanism while restoring the knee’s original joint line, axis of rotation, and limb alignment.
Together, this approach is designed to support early confidence, smoother recovery, and a resurfaced knee that moves more naturally long term.
PURE MOTION PARTIAL KNEE RESURFACINGSM
More than muscle sparing. Motion restoring. Joint preserving.
To learn whether Pure Motion Partial Knee ResurfacingSM is right for you, call to schedule an appointment with Dr. W. Gaines Cumbie or join one of his free educational virtual webinars.
FREQUENTLY ASKED QUESTIONS: PURE MOTION PARTIAL KNEE RESURFACINGSM
It is a partial knee replacement defined by two required principles: a complete muscle- and tendon-sparing approach and patient-specific implant positioning designed to restore the knee’s pre-arthritic joint line, axis of rotation, and limb alignment.
Yes. Both terms describe replacing only the worn joint surfaces within one knee compartment while preserving the healthy parts of the knee.
It is only appropriate when arthritis is limited to a single compartment and the rest of the knee remains healthy and stable.
Because more of the knee’s native structures are preserved, many patients report a more natural-feeling knee.
If arthritis develops in other compartments, conversion to a total knee replacement remains an option.
Pure Motion standardizes both how the knee is accessed and how implants are positioned-preserving muscle, restoring native anatomy, and supporting more natural motion.
