Kristaps Porziņģis' Medial Retinaculum Tear & Tibialis Posterior Subluxation

"When the medial retinaculum ruptures, your inner ankle tendon loses its physical seatbelt. Attempting to sprint or jump without fixing this structural sleeve is like driving a high-speed train on a curved track with a broken outer rail—eventually, the train will jump the tracks."

For basketball fans and athletic trainers alike, the sports news cycles of the NBA finals highlighted a rare, complex injury: Kristaps Porziņģis' medial retinaculum tear. This injury, occurring in the inner ankle, is completely different from a standard ankle sprain. It immediately compromises the structural stability of the foot's primary support tendon, leaving athletes unable to push off effectively.

Standard ankle rehabilitation protocols are highly dangerous here. Simply performing lateral band walks or balance drills on an unstable ankle bone will repeatedly pull the posterior tibialis tendon out of its groove, grinding the tissue. To recover, you must follow a structured, protected load progression.

To safely navigate a medial retinaculum tear recovery, you must understand the unique mechanics of the posterior tibialis tendon and prevent its subluxation. This article breaks down the anatomy of this injury and presents progressive sports physical therapy guidelines.

The Inner Ankle Seatbelt: Medial Retinaculum Anatomy

The posterior tibialis muscle originates in the deep calf and travels down the leg, transitioning into a thick tendon. This tendon hooks sharply behind the medial malleolus, the bony bump on the inside of the ankle, before inserting into the navicular bone of the foot. The tibialis posterior is the primary dynamic stabilizer of the inner foot arch, preventing the foot from collapsing inward during landing.

To keep this tendon in place as it bends around the ankle bone, a thick fibrous band called the flexor retinaculum wraps over it. A tear in this retinaculum allows the posterior tibialis tendon to slip forward over the bone (subluxation) whenever the foot is flexed upward and turned outward. This subluxation causes severe friction, inflammation, and loss of arch control.

Clinical sports data indicates that posterior tibialis tendon subluxation accounts for less than 0.5% of all athletic ankle injuries, making it a frequently misdiagnosed condition. The tendon shifts by 5 to 8 millimeters out of its groove during movement, causing an audible snap and immediate loss of foot arch support. Rebuilding the structural support is critical to prevent tendon degeneration.

The Clinical Opinion: Avoid Early Lateral Ankle Balancing

The Progressive Retinaculum Rehab Protocol

Rehabilitation must prioritize preventing subluxation while gradually restoring tendon strength. Move through these phases only when pain-free.

Phase 1: Protected Immobilization and Swelling Control

In the acute stage, the torn retinaculum must be protected from stretching. The foot is placed in a rigid walking boot with a medial arch support insert to prevent the inner foot from collapsing. Rest, elevation, and compression wraps are used to manage swelling around the medial malleolus. Avoid any active movement that turns the foot outward. Continue this protection for 3 to 4 weeks.

Phase 2: Straight-Line Isometric Strengthening

Once initial healing has occurred, begin isometric strengthening without moving the joint. Sit on the floor with your foot flat against a wall. Press the inner edge of your foot inward against the wall (inversion) without allowing the ankle to bend. Hold this contraction for 10 seconds, then relax. This contraction stimulates the posterior tibialis muscle without causing the tendon to slide. Perform 3 sets of 10 holds daily.

Phase 3: Protected Eccentric Arch Loading

To prepare the tendon for sports loads, perform eccentric arch raising. Stand with the balls of your feet on a flat floor, holding onto a counter for balance. Rise up onto both feet, then shift your weight to your uninjured leg and lower down slowly. Keep your ankle aligned to prevent the foot from rolling inward. Perform 3 sets of 10 slow descents daily, gradually transitioning to single-leg loading.

Rebuilding Inner Ankle Stability

Recovering from a rare tendon injury requires patience and structured care. To protect your foot arch, ensure your athletic footwear features supportive midsoles and avoid running on soft, uneven sand during early recovery.

For related lower limb conditioning guides, read our clinical guide on ankle sprain recovery and our article on Achilles tendon loading. To learn how foot alignment affects the entire leg, see our guide on plantar fascia support to protect your dynamic arch.

Featured image attribution: "Kristaps Porziņģis 2022" by Joe Glorioso, licensed under CC BY-SA 2.0. Modified by cropping and compositing.