What is Genu recurvatum?
This means hyperextension at the knee joint. It may be congenital or acquired. 5-10 degree hyperextension of knee is considered as physiological and hyperextension more that is pathological. This condition is also known as the back knee. It is common in women than in men and people with familial ligamentum laxity. the hyperextension which has occurred may be mild, moderate or severe. The development of this genu recurvatum may cause knee pain and even lead to knee osteoarthritis.
Genu Recurvatum Causes:
- Ligamentum laxity in such conditions like Marfan’s syndrome, charcoatsarthropathy
- Muscle imbalance: in case of spasticity in knee extensors such conditions like hemiplegia due to stroke
- Quadriceps weakness
- Asymmetrical epiphyseal growth: anterior epiphyseal growth plate undergrowth or posterior epiphyseal plate overgrowth may lead to genu recurvatum.
- Malunited fractures
- Polio is the commonest cause of acquired genu recurvatum.
- Compensatory: to compensate the opposite side shortening, one may adapt hyperextension. Recurvatum may be associated with genu varum or valgum.
- Upper motor neuron lesion such as hemiplegia, lower motor neuron lesion such as post-polio syndrome.
- Cerebral palsy, muscular dystrophy
- Increase hyperextension on weight-bearing greater than that in non-weight-bearing suggests ligamentum laxity
- Check the length of hamstrings, quadriceps, gastrocnemius, and soleus – quadriceps contracture may result in hyperextension
- Check the strength of quadriceps, hamstrings, ankle dorsiflexion and hip muscles.
- Measuring the limb length finds out associated genu valgum or varum.
- Checking the ligamentum laxity by valgus\ varus stress test and anterior-posterior translator force over the tibia.
- Gait- hand to knee gait due to quadriceps weakness, anterior trunk bending and equines gait
- Inspect the client in standing from the side by standing on both legs and standing on a single leg . also check the hyperextension in supine lying.
Diagnosis can be done by X-ray and magnetic resonance imaging ( MRI) to classify the type of genu recurvatum along with the physical examination and analysis of the gait.
It depends on the cause.
- In the case of ligamentum laxity, knee orthosis may be provided.
- In the case of muscle imbalance, quadriceps weakness is often a cause. knee orthosis, progressive strengthening of quadriceps may be recommended.
- Genu recurvatum in spastic patients can be managed by the relative strengthening of quadriceps, ankle plantar flexors, and hip retractors
- In the case of asymmetrical epiphyseal growth, correction by osteotomy may be considered. Anterior open ways or posterior closed ways osteotomy with internal fixation and immobilization is required.
- Compensatory genu recurvatum requires footwear compensation on the opposite shorter limb side.
- Stretching of tricep sure, strengthening of hip extensors, quadriceps
- Bracing around the knee joint.
- Proprioceptive awareness by verbal cueing, which is helpful to get direct sensory feedback like posterior knee taping
- Along with muscle strengthening exercises, the patient should progress with weight-bearing exercises like a single-leg standing, lunges, step-up’s – forward and backward, squats, mini dips, resistive terminal extension exercises
- Gait training
- Functional tasks like stair climbing can also be trained.