Kinematic Alignment in Knee Replacement: Restoring Your Natural Motion

Kinematic alignment is a surgical technique used in total knee replacement (TKR) that focuses on restoring the knee’s natural movement and alignment, rather than forcing it into a standardised position.

In simple terms, this approach matches the replacement components to the patient’s own anatomy: how their knee naturally bends, rotates, and bears weight before arthritis developed.

Traditional “mechanical alignment” aims to make every leg straight, whereas kinematic alignment aims to make each leg move as it was naturally designed to.

The diagram visually contrasts these two surgical philosophies: Panel (a) illustrates Kinematic Alignment by setting the implant parallel to the patient's native joint line (the TEA), while Panel (b) shows the Mechanical Alignment approach, positioning the implant perpendicular to the overall leg axes (FMA and TMA). 

By respecting a person’s unique bone structure and ligament tension, this method can help the new joint feel more natural and move more smoothly. Versus Arthritis¹ notes that modern alignment techniques increasingly prioritise comfort, function, and early recovery rather than one-size-fits-all positioning.

In a mechanical alignment knee replacement, surgeons position the implants relative to fixed mechanical axes, usually aligning the leg in a straight line from hip to ankle.

By contrast, kinematic alignment restores the pre-arthritic joint lines and rotations, aligning the components based on the patient’s original joint motion and soft tissue balance.

At OI, we use digital surgical planning software to analyse joint mechanics and customise implant positioning to each patient’s anatomy. This ensures accurate restoration of natural alignment and soft tissue balance.

Many patients and surgeons favour kinematic alignment because of its potential to improve comfort, motion, and satisfaction after surgery. Reported benefits include:

• A more natural-feeling knee after replacement
• Improved early range of motion
• Higher patient satisfaction compared with traditional alignment methods
• Reduced need for soft tissue releases during surgery
• Potentially faster recovery and return to daily activities

A 2023 study in the Journal of Arthroplasty² reported that patients undergoing kinematically aligned total knee replacement had higher satisfaction and function scores at one year compared with mechanically aligned procedures.

Kinematic alignment may be a suitable option for:

• Patients with osteoarthritis or degenerative knee disease
• Individuals seeking a more personalised surgical approach
• Those with balanced ligaments and no severe deformity
• Active adults who want their knee replacement to feel “more like their own”

Your orthopaedic consultant will use detailed imaging and digital pre-operative planning to determine whether kinematic alignment is appropriate. Some patients with complex deformities or previous surgery may still be better suited to a mechanical alignment technique.

Read more on our software: Precision and Teamwork: Using Software for Knee Replacements

At Orthopaedic Innovation, your knee replacement journey includes:

1. Pre-operative Assessment: Digital 3D planning software is used to analyse joint mechanics and determine optimal implant positioning.
   
   
2. Surgery: The implant is positioned according to the digital plan, tailored to your individual anatomy for precise alignment and natural balance.
   
   
3. Recovery: Most patients begin mobilising within 24 hours of surgery and continue guided physiotherapy soon after.
   
   
4. Rehabilitation: A structured programme helps restore strength, flexibility, and confidence in your new joint.

The operation typically lasts around 40 minutes, depending on your overall health and the complexity of your knee condition. Learn more about Knee Replacement at OI.

While the primary aim of kinematic alignment is to restore natural motion and comfort, studies suggest that it does not compromise implant longevity when performed accurately.

Modern implant design, digital surgical planning, and precise intraoperative assessment have all improved long-term outcomes.

By combining patient-specific planning with accurate surgical execution, this approach helps achieve both comfort and durability.

Kristian and I have spent the last 20 years of our careers focusing on knee alignment and correcting this through realignment surgery.

We have taken these principles and applied them to how we perform partial and total knee replacement surgery, by fine-tuning each operation to restore the patient’s own kinematic alignment.

Traditionally, most knee replacements are performed using so-called mechanical alignment, which follows a “one-size-fits-all” approach. In contrast, kinematic alignment takes into account each patient’s natural anatomy and movement pattern, allowing us to plan and perform surgery tailored precisely to the individual.

Since adopting this approach, we have seen significantly improved results compared with our earlier, more conventional methods that did not consider the patient’s personal kinematics. We believe this represents a major step forward in knee replacement surgery, and we are extremely pleased with the outcomes it provides for our patients.