You’re observing your patient during gait training when you notice their knee locks backward into extension every time they accept weight. That moment of hyperextension—often with a visible snap into place—is genu recurvatum, and it’s more than just a quirky gait deviation. It’s a signal that the knee’s stability mechanisms are compromised, and it demands your attention.
What is Genu Recurvatum?
Genu recurvatum (JEE-noo ree-kur-VAH-tum) literally translates to “backward knee.” It’s a knee hyperextension deformity where the tibia moves posterior to the femur beyond the normal 0° of extension. This can be a structural alignment issue (bony geometry) or a functional problem caused by soft tissue laxity, weak quadriceps, or neurological conditions affecting motor control. In gait, it most commonly appears during the stance phase when the knee fails to maintain a slight flexion angle.
Why Genu Recurvatum Matters in Physical Therapy Practice
This isn’t just a biomechanical curiosity. Repeated hyperextension stresses the posterior capsule, PCL, and popliteal structures, leading to joint degeneration and chronic pain. It also signals impaired proprioception and weak quadriceps control. Addressing it is critical to your Plan of Care because it directly affects weight-bearing safety, fall risk, and long-term joint health. For neuro patients, it’s often a compensatory strategy for weak quads or plantarflexors, so your intervention must target the root cause, not just the symptom.
What You’ll See in the Clinic
You’ll notice the knee hyperextending during mid-to-terminal stance, often accompanied by a backward lurch of the trunk. The patient may report a feeling of “locking” or “instability” and may have a visible genu recurvatum at rest in standing with an anterior pelvic tilt. In severe cases, you’ll see it during transfers or stair climbing.
“Patient with left hemiparesis presents with 15° genu recurvatum during stance. Reports ‘knee gives way’ but actually locks backward. Quad strength is 2/5, proprioception impaired. Plan: quad strengthening in weight-bearing, knee orthosis trial, and gait training with verbal cue to ‘keep knee soft.'”
Common Pitfall & Pro Tip
⚠️ Pitfall: Treating the hyperextension as purely a ligament issue. Many students jump to bracing or PCL precautions without addressing the underlying quadriceps weakness or impaired motor control. Also, don’t assume it’s always pathological—some individuals have normal 5-10° hyperextension without symptoms.
💡 Pro Tip: Use a mirror or biofeedback to help the patient see and feel their knee position. Cue them to “keep a soft knee” or “think of a spring under your heel.” For neuro patients, weight-bearing exercises like mini-squats on the affected leg can retrain co-contraction of quads and hamstrings.
Memory Aid for Genu Recurvatum
Think “Recurve bow”—the knee bends backward like a recurve bow’s limbs. If you picture the bow’s curve pointing backward, you’ll remember that recurvatum = hyperextension, not flexion. Also, remember “Knee in the past”—it’s going back beyond neutral.
NPTE Connection
Watch for this in gait analysis questions, neuro rehab scenarios (stroke, MS, CP), and orthotic prescription items. You may be asked to identify the best intervention to reduce genu recurvatum or to recognize it as a contraindication for certain exercises.
Related Physical Therapy Concepts
Genu recurvatum often coexists with quadriceps weakness, hamstring tightness, or ankle plantarflexor insufficiency (which prevents adequate tibial advancement). It also relates to Knee Orthoses (e.g., KAFO) used for severe cases, and it’s a common post-polio or post-stroke gait deviation. Understanding knee joint biomechanics and proprioceptive training is essential for effective management.
Quick Reference
✓ Normal ROM: 0° extension (up to 5-10° hyperextension is non-pathological) ✓ Priority level: High if affecting gait/function; Moderate if asymptomatic ✓ PT Interventions/Considerations: • Strengthen quadriceps (closed-chain, eccentric control) • Improve proprioception (balance board, single-leg stance) • Gait training with verbal/tactile cues for knee flexion in stance • Consider orthotic trial (KAFO or knee sleeve with extension stop) • Stretch hamstrings and gastroc if tight • For neuro patients: address underlying motor control and spasticity
Bottom line: Genu recurvatum is a visible clue to deeper stability deficits. When you see that backward knee, dig into the cause—your patient’s knee will thank you.