How to tell if you have knock knees:
If you suspect you may have knock knees, you can make the diagnosis of knock knees at home.
Stand upright in front of a mirror with your knees touching and your kneecaps facing forward.
If your ankles are apart by more than 8cm then you most likely have knock knees.
The medical term for ‘knock knees’ is genu valgum.
What causes knock knees?
There are a few reasons you may have knock knees:
Developmental: Knock knees is so common in young children that the presence of knock knees in children is considered a normal stage of development up to the age of about 10.
Following lower limb injury at a ‘growth center’: Most of the growth in the lower limb is from places called ‘growth centers’ above and below the knee. Growth centers house specialized cells that multiply and cause the limb to get longer in children and teens.
This means that if any injury occurs at these ‘growth centers’, when one is still growing, it is possible that the damaged cells will cause distorted growth at the knee, resulting in knock knees as you grow up.
Following a lower limb fracture: If you have suffered from a fracture away from the growth centre, sometimes your bones can also heal in an abnormal position after a fracture, causing the appearance of knock knees.
Following a soft tissue injury at the knee: More severe injuries that may happen at the knee can cause your knee ligaments to be torn or stretched, causing them to be loose.
Due to bone disease: Some familial bone diseases can also cause knock knees. This is because the quality of the bone is “softer” than normal bone, which causes the bone to bend.
Due to poor bone quality: Rickets (low vitamin D) and low calcium can cause deformities in the long, weight-bearing bones.
Due to advanced joint disease and degeneration: Advanced arthritis can also result in knock knees, and this is usually seen in middle-aged and older adults.
Can knock knees be surgically corrected?
Yes.
Procedures for children: After establishing the correct diagnosis and cause, in general, at least two operations will need to be carried out in children and teens (who may still be growing), to correct knock knees.
Dr Maina places a staple or small plate and screws across the growth centre inside the knee in the first step of a procedure, which is known as “growth modulation”.
This slows growth on the inside of the knee, and gradually brings the limb into improved alignment, as the child/teen grows older
Dr Maina follows up over a few months, with several repeat X-rays to see the progress and correction of the knee deformity.
Children generally need a second surgical procedure to remove the implants after correction has been achieved. This is usually done as a day procedure.
In some teens and children, the correction is not as effective as one would expect, so occasionally there is a need to do an additional surgical procedure to intentionally damage one half of the growth plate to cause permanent growth arrest. This forces a more aggressive correction, and is called a ‘hemiepiphysiodesis’.
Girls older than 14 years and boys older than 16 years of age will generally have reached their maximum growth in the lower limbs and may no longer have active growth centers, so we treat them as we do adults. This is described below.
Procedures for adults: When an young adult with knock knees experiences pain or has early signs of joint damage, surgery may be required that breaks the bone to correct its alignment. This is called a “corrective osteotomy”.
This is done through a cut on the outside of one’s thigh just above the knee. Dr. Maina slightly overcorrects the deformity gradually during the surgery, and stabilizes the bone in this position using a specialized ‘wedge plate’ that maintains the gap in the surgically broken bone.
Older adults who typically present to Dr Maina’s rooms with knock knees have usually developed instability and severe osteoarthritis as a complication of longstanding malalignment. Their knee pain is located on the outer side of the knee joint and in the front of the knee. In these older patients – after exhausting reasonable non-operative treatment options – Dr Maina may recommend a knee replacement. This surgery will address both the arthritis and malalignment.
Surgical planning: Before surgery, Dr Maina requires standing x-rays of the lower limbs/knees. This helps her plan the surgical correction of your knock knees. The more severe the deformity, the greater the degree needed to correct.
How long does it take to recover from knock knee surgery?
In children who have a staple or small plate inserted to stop growth, their pain is minimal and they usually mobilize and return home the day after surgery. They may occasionally use crutches to take the weight off to limit pain for a short period of time.
In adults who have undergone a corrective osteotomy (breaking and realigning the strongest bone in your body – the femur), you will only be able to start standing on that leg between 6 to 8 weeks following surgery. In that period of time, you will need to use crutches, wear a rigid knee brace for support and undergo physiotherapy. Swimming and low resistance exercises will be possible after about two months. High level athletes can return to sport up to three years from the time of surgery.
Following knee replacement surgery, you will be required to stand and take a few assisted steps as soon as the afternoon of your surgery. One can return to low impact and moderate activity – including driving – from six weeks after surgery.
Is knock-knee surgery painful?
All surgery is done when you are unconscious, under anaesthetic. When you wake up, you will also receive regular pain medication after the surgery, so any pain will be well-controlled.
Growth modulation is a brief, straightforward surgical procedure and is done through a very small incision, so the pain is minimal.
Corrective osteotomies are more invasive and are subsequently more painful. The pain usually decreases substantially after the first week following surgery.
Knee replacements are painful surgeries, but, overall, the pain relief from the definitive treatment of arthritis outweighs the short-lived discomfort of surgery.
Can knock knees be cured without surgery?
Since being knock-kneed is a part of normal development in kids, Dr Maina usually follows children up to twice a year to check their progress. Knock knees usually correct themselves between 8 and 10 years of age. If, over this time, the condition worsens (or persists at the age of 10), Dr Maina may recommend surgery.
In young adults, there are several powerful clinical trials which show that select exercise programmes can improve strength, efficiency and position of the lower limbs in adults with knock knees. This improved strength reduces strain on the knee, reducing the frequency of injuries and delaying the progression of osteoarthritis. These exercises may improve the appearance of knock knees, but do not “cure” knock knees.
Aside from physiotherapy and exercise to decrease the severity of symptoms in older adults, non-operative steps include:
- The use of painkillers
- Orthotics or assistive devices (knee braces and shoe wedges) to ‘offload’ the affected part of the knee joint
- Dr Maina performs consulting room injections into the knee of
- Your own platelet-rich plasma (referred to by some as “stem cells”)
- Steroid injections into the knee
- Gel supplement injections.
- Weight loss reduces the strain across the knee (for every 1kg of weight lost, the pressure on the front of the knee is reduced by 4kg!)
Do knock knees get worse with age?
That depends on the cause of the knock knees.
If rickets and calcium deficiencies go untreated, they may result in progressive deformities of the entire limb – not just at the knees.
If there was an injury to the ligaments of the knee, then the ligament may heal in a stretched position. The progressive stretching and abnormal wearing down of the joint itself can worsen the knock knees with age.
If one gains weight and suffers from knock knees, the weight gain will worsen the alignment over time and put more pressure across the knee joint.
In family-related bone diseases, knock knees may get worse with age. Pagets disease of bone is one example.
How can I straighten my knock knees naturally?
Weight loss has been shown to improve alignment and decrease pain at the knees.
While your posture and balance at the knees can be improved through exercise, the alignment abnormalities that may cause knock knees cannot be ‘cured’ through exercise alone.
Lunges, squats and other exercises can help strengthen muscles and improve the appearance of knock knees. These exercises should be done, with attention paid to correct technique in order to avoid injuries at the knee.
Always exercise in front of a mirror or ask your training partner/physiotherapist to check your training technique.
When should I consider knock knee surgery as an option?
Elective surgery is always a last resort.
Surgery is an option when all other reasonable options are exhausted or when your pain and deformity is severe.
Dr Anne Maina
Specialist Orthopaedic surgeon
MBBCh (Wits), FC Orth (SA), MMed Ortho (Wits) CIME
References:
- Jenna Fletcher. All you need to know about knock knees (genu valgum). Healthline.com. Reviewed April 22, 2020. Accessed 3 May 2022: https://www.medicalnewstoday.com/articles/319894
- Jafarnezhadgero A, Ghorbanloo F, Fatollahi A, et al. Effects of an elastic resistance band exercise program on kinetics and muscle activities during walking in young adults with genu valgus: A double-blinded randomized controlled trial. Clin Biomech (Bristol, Avon). 2021 Jan;81:105215. doi: 10.1016/j.clinbiomech.2020.105215. Epub 2020 Nov 11. PMID: 33203537.
- Zajonz, D., Schumann, E., Wojan, M. et al. Treatment of genu valgum in children by means of temporary hemiepiphysiodesis using eight-plates: short-term findings. BMC Musculoskelet Disord18, 456 (2017). https://doi.org/10.1186/s12891-017-1823-7
