Below is a patient, 3 months post operatively, who underwent a Kalix Subtalar Joint Implant, left foot.
Patient's Diagnosed:
- Hypermobility Syndrome (lax ligaments)
- PreClinical Clubfoot Deformity

Knee Bent Test Findings
Knees Straight - weight on the calcaneus (occurs during early stance phase of gait)
- The Kalix Implant decreases the rearfoot pronation in the left foot
- Prior to surgery, rearfoot hyperpronation pattern: Left > Right
- After surgery, rearfoot hyperpronation pattern: Right > Left
Knees Bent - weight over the forefoot (occurs during mid to late stance phase of gait)
The Kalix Implant distorts the motion in the subtalar joint. As the body's weight is transferred forward over the metatarsals, the left leg undergoes lateral lurch left (See Lateral Lurch Resulting from a Kalix Prosthesis) as the foot continues to hyperpronate.
The right foot (without the implant) continues to hyperpronate as the body's weight is transferred forward over the metatarsals. However, the motion in the right leg is not artificially distorted by an implant.
Prof/Dr Brian A Rothbart
Chronic Pain Elimination Specialist
Discovered the Rothbarts Foot Structure and the PreClinical Clubfoot Deformity
Developer of Rothbart Proprioceptive Therapy
Inventor and Designer of Rothbart Proprioceptive Insoles
Founder of International Academy of Rothbart Proprioceptive Therapy
Author of Forever Free From Chronic Pain