Valgus knee, also called knee valgus or 'x' legis the second most common lower limb deformity problem in children and can cause abnormal gait function, misalignment during movement, and an increased risk of knee arthrosis. Physiologically, correct alignment involves an angle between the femur and tibia of 170° outwards (the knee is therefore slightly inwards in relation to the vertical); a valgus knee is therefore when the angle decreases, bringing the knee further inwards in relation to the vertical axis.

As the knee valgus angle increases, mechanical stress damage to the cartilage caused by misalignment of the bones is the main cause of osteoarthritis, a progressive disease that leads to to pain, inflammation, cartilage wear and disability in activities of daily livingresulting in a long-term surgical indication. Sources of joint stress include bone misalignments, mechanical injuries, repeated microtrauma over time (walking or running, high-impact sports, training sessions with too high loads) and excess body weight.

Valgus knee: causes

Causes of bad knees include: rickets, obesity, heredity, developmental delay, muscle imbalanceSignificant correlation between reduced curvature of the spine and valgus knee position. In a properly developing child, the varus knee position is observed in the neonatal and infant period until the child begins to walk unaided, at which stage the knees spontaneously go into valgus position in pre-school and gradually shift into a neutral position after the age of 7. If the position of the knee in valgus or varus remains for a longer period of time than the physiological norm indicates, or worsens with age, biomechanical compensatory mechanisms may appear that alter the position of the other joints of the lower limb, pelvis and spine.

For example, varus knees increase internal knee rotation and external hip rotationchanging foot position and gait.

Both valgus and varus knees significantly overload the knee joint, change the position of the kneecap in the joint with the femur, and increase the risk of damage to tendons, ligaments and articular cartilage, risk factors for the onset of arthrosis. 

Valgus knee: corrective exercises

A corrective lower limb exercise programme can reduce knee valgus by increasing ankle flexibility, hip extension and abduction strength, factors that contribute to improved limb alignment, since excessive knee valgus is most likely caused by a series of muscular imbalances of the hip and ankleTherefore, it is considered necessary to study global strategies focusing on the hip and ankle joints to determine whether knee alignment can be corrected during movement.

A comprehensive approach focusing on the hip and ankle joints with improved mobility and strength is recommended, with exercises focusing on the muscles of both joints, performed in a specific sequence through a corrective exercise strategy that may include relaxing dominant muscles, lengthening tense muscles, and strengthening weak muscles.

Identifying inadequate movement patterns allows physicians to prescribe corrective exercise interventions targeted at high-risk individuals, for example, considering the two-legged squat as a screening activity to analyse functional movement, during which, if a knee valgus is observed, elevations under both heels can be introduced, used to distinguish an ankle or hip muscle problem as a major contributor to the dynamics of the valgus knee.

The heel lift causes plantar flexion of the ankle and relieves the back flexion restriction caused by the calf muscles, thereby normalising the alignment of the knee during the squat. 

Valgus knee affects quadriceps activationTherefore, selective rehabilitation training of the quadriceps femoris should be considered to prevent pain or deformities from valgus knee, which is influenced by the imbalance between the inner part of the quadriceps (vastus medialis) and the outer part (vastus lateralis).

The valgus knee affects the activation times between the vastus medialis and lateralis during contraction and this can be controlled to relieve knee pain and strengthen the quadriceps, through a selective reinforcement programme for the vastus medialisnecessary for people with knee valgism; in other words, a rehabilitation programme to balance the vastus medialis and lateralis may be necessary for individuals with knee pain or injuries. 

Stretching the iliopsoas, gluteus maximus, gluteus medius, rectus femoris, biceps femoris, quadriceps and calf muscles can eliminate tension on the knee, helping to avoid joint pain or hamstring from structural misalignment, however, previous studies have investigated the association between lower-limb pelvic stabilisation and knee alignment, showing that women exhibit knee movements more towards valgus and internal hip rotation than men.

These movements could be controlled by working on the pelvic and hip muscle groups that contribute to the opposite movement to valgus (iliopsoas, as an external hip rotator, to control internal hip rotation). A recent study showed that increased loading of the iliotibial fascia, which is presumed to transmit the force of the tensor fascia lata and the gluteus maximus, could increase valgus when tested in a non-loaded condition in a cadaveric model, so it is suggested that attention should also be paid to the treatment of the latter, with targeted exercises to relieve tension at the lateral aspect of the knee. 

Valgus knee in children: should it be corrected?

Correct alignment is a substantial factor influencing the prevention of age-related joint pathologies, in fact, static frontal alignment of the lower limb, particularly that of the knee, is correlated with anterior cruciate ligament injuries, meniscal injuries, patellofemoral pain syndrome and biomechanical stress on the cartilage, whereas improved alignment is associated with a reduced risk of cartilage problems associated with loading. 

Idiopathic valgus knee is a growth disorder diagnosed Frequently in adolescence, although with wide variations in degree, cause and therapeutic relevance, particularly in the growth phase from 2 to 11 years of age, a minor valgus deformity of 5-10° is considered physiological and may persist beyond this age and depending on constitution.

These development-related growth changes usually correct spontaneously and in the case of mild persistent knee valgus can be successfully treated conservatively, through the use of a rehabilitation programme aimed at improving movement and managing any symptoms.

In the case of asymmetrical or unilateral deformities, it is necessary to rule out metabolic, genetic, post-traumatic and other (obesity) causes, whereby a progression or persistence of the pathology can be expected, which has negative effects on the further development and mobility of the affected child and may contribute to the early development of gonarthrosis, therefore, if the possibilities of conservative therapy have been exhausted, surgical straightening of the leg is the standard of care. 

Hemiepiphysiodesis has become the gold standard, particularly as an alternative to osteotomy for leg straightening in adolescents, various techniques for epiphyseiodesis involving screws, staples and wires have been tried and described, however, despite good success rates, complications such as material fractures and loosening of the implant as well as damage to the growth cartilage have often been reported, with complication rates (mainly screw breakage) of 6-16% for the eight plates.

Due to the rebound phenomenon, a mild varus is particularly indicated for children with a risk profile (obesity, epi. Dysplasia, etc.) and still growth potential to avoid relapses as growth progresses. Corrections requiring surgery may be necessary if there is a lack of patient compliance or due to procrastination on the part of family members, who only consult the doctor in cases of deformities that are now significant. Incomplete corrections have also occurred in a certain percentage of cases, although only patients with low growth potential and an average implantation age of 14 years have been affected.

Valgus knee surgery: is it necessary?

Guided growth surgery for lower limb deformities took the place of the old corrective osteotomies and its effectiveness and safety have been generally recognised. It is widely accepted that paediatric orthopaedic surgeons should only use corrective osteotomies as a salvage of failed guided growth surgery. Growth modulation by temporary haemiepiphysiodesis using eight plates for the treatment of valgus knee is a gentle and effective procedure, particularly in young patients with high growth potential and risk groups such as obese patientsslight overcorrection is desirable due to the rebound phenomenon. In children with only low growth potential (older than 14 years), due to the low correction potential, the indication must be strictly reviewed and any failure of therapy must be discussed with the patient, whose compliance is crucial to avoid short- and medium-term complications.

Bent knees: when to correct them?

Predictors of spontaneous resolution of severe persistent deformities of the lower limbs despite successful medical treatment of nutritional rickets in relation to patient and disease characteristics have yet to be identified in the literature. 

In this regard, age and severity of the deformity are important factors, The exact indications of the surgeries currently used to correct knee deformities in these children remain undetermined and mainly subject to surgeon preference, but a very recent prospective natural history study suggested that 18th knee valgus over 9 years old usually does not correct and may require surgery. 

Several clinical studies have shown that the various techniques of haemiepiphysiodesis are effective and safe for guided good growth, with marginal differences related to complication rates, surgical time, cost and quality of life. The valgus knee in children with nutritional rickets remains a disability problem worldwide, also considering severe deformities of all limbs, gait abnormalities and increased fracture risk, however, no studies have been conducted to evaluate the effectiveness of guided growth in knee deformities in nutritional rickets. Many believe that using a Kinesio tape for the knee may serve; in reality it does not.

Valgus knee orthotics: to buy them or not?

Special shoes are not effective For the prevention or treatment of valgus knee, on the other hand, if the feet also have a valgus stance and foot fatigue is symptomatic, orthotics are appropriate to support the plantar vault, indirectly also stimulating potential knee alignment, however, they do not correct the valgus, but relieve foot tension, easy fatigability and calf pain.

The role of orthotics in controlling or correcting knee valgus has not been proven and is controversial and, according to the literature, the only indication for a knee and ankle orthosis is to support the ligaments of the knee and prevent them from overstretching, a practice used in pathological valgus knees. The role of orthotics in controlling or correcting knee valgus is unproven and controversial and, according to the literature, the only indication for knee and ankle orthotics is to support the ligaments of the knee and prevent them from overstretching, a practice used in pathologic valgus knees.

Conclusion

Valgus knee up to 7 years of age is physiological and not pathologicalo, in fact, the problem is the adolescent or child over 8 years of age who has moderate to severe knee valgism, over 18°. The patient complains of thigh and calf pain and easy fatigability, the child walks with knees rubbing, feet apart and one leg swinging over the other, often causing concern to family members who initiate the diagnostic process. Due to the misalignment and the increased internal angle between the femur and tibia that alters the function of the quadriceps, the patella subluxes laterally; causing instability of the patellofemoral joint. The shoes show a medial collapse of the upper parts and is the result of abnormal loading forces on the ankle and foot.

Parents seek active treatment and commonly believe that the deformity causes degenerative and crippling arthritis of the knee, however, to properly manage the problem, we should first determine the cause of the knee valgus through careful history taking, physical examination, and appropriate imaging studies. In most cases the valgus knee corrects spontaneously, in pathological cases the first indication is rehabilitation, with an exercise programme aimed at managing pain and improving walking. For severe pathologies or for deformities that do not benefit from rehabilitation, the surgical approach is indicated, which in recent years favours guided growth rather than corrective osteotomy.

Source

Park S, Kong YS, Ko YM, Jang GU, Park JW. Differences in onset timing between the vastus medialis and lateralis during concentric knee contraction in individuals with genu varum or valgum. J Phys Ther Sci. 2015 Apr;27(4):1207-10.

Bell DR, Oates DC, Clark MA, Padua DA. Two- and 3-dimensional knee valgus are reduced after an exercise intervention in young adults with demonstrable valgus during squatting. J Athl Train. 2013;48(4):442-449. doi:10.4085/1062-6050-48.3.16

Lucha-López MO, Tricás-Moreno JM, Gaspar-Calvo E, Lucha-López AC, Vidal-Peracho C, Hidalgo-García C, Caudevilla-Polo S, Fanlo-Mazas P. Relationship between knee alignment in asymptomatic subjects and flexibility of the main muscles that are functionally related to the knee. J Int Med Res. 2018 Aug;46(8):3065-3077.

Dr Davide Maria Condoleo

Physiotherapist with experience in orthopaedic, neurological and sports medicine, with excellent teamwork skills.
Skills in the management of the post-surgical patient and the patient with musculoskeletal problems.