Physical Therapy in Cleburne for Pediatric
Children with Blount disease often need surgery to restore normal knee alignment and reduce pain. The result is decreased disability and improved function. Blount disease is a condition of bowlegged knees, also known as tibia vara in medical lingo. Surgical correction aims to create a more normal angle between the lower end of the femur (thigh bone) and the upper portion of the tibia (lower leg bone).
Two angles used to diagnosis Blount disease are measured on X-rays: the metaphyseal-diaphyseal angle (MDA) and femoral-tibial angle (FTA). A MDA angle between 11 and 15 degrees is borderline tibia vara. More than 15 degrees increases the risk that tibia vara (the bowlegged position of the knee) will continue to get worse over time.
Everyone is concerned about restoring a more normal angle at the knee for children with Blount disease. But no one has looked at the effect of metaphyseal-diaphyseal angles (MDAs) after surgery on patient satisfaction. The surgeon is happy everything lines up nicely. But are the patients pleased with the results? Does it solve their knee deformity and disability? The authors of this study looked at pain, function, and satisfaction months to years after the operation was done in a group of 41 patients (total of 50 knees).
In order to find out how patients felt after surgery for Blount disease, a group treated at two hospitals were asked to fill out a survey called the Blount's Outcome Questionnaire. The survey was specifically designed for this study by modifying a previously existing tool called the AAOS Pediatrics Parent/Child Outcome Instrument. The patients also rated their knee pain on a scale from zero (no pain) to 10 (worst pain). When pain was present bilaterally (on both sides), pain levels were recorded separately for each knee.
Average age of the children who participated in the study was between nine and 10 years old. Most of the children were born with Blount disease. This type is called infantile Blount disease. There were also children included who had juvenile Blount disease (developed during the teen years) and insidious disease (exact date of onset was unknown).
When the scores were added up and the results were analyzed, the overall rate of satisfaction for the entire group was 93 per cent. Patients who had more than one surgery had lower satisfaction rates. The lowest pain ratings were reported when the metaphyseal-diaphyseal angle (MDA) was between zero and -10 degrees and when the femoral-tibial angle (FTA) was between zero and +5 degrees. The higher the MDA, the more varus or leg bowing that's present. There was a link between both the MDA and the FTA and patient satisfaction. Small changes in the FTA lead to big changes in satisfaction.
What does all that mean? Basically, optimal surgical correction as outlined (measured angles between -10 and +5 degrees) does bring about greater patient satisfaction. Correction isn't just to look good on X-ray or in a bathing suit. When these angles are lined up, there is a more normal and even distribution of weight and load on the upper tibia. Without correction, too much pressure is placed on the lateral (outside edge) of the knee. Ligaments on the inside (medial) edge of the knee get stretched out to the point that the knee can become unstable. In a growing child, these uneven pressures can create a leg length difference and even more deformity.
Two other factors affecting pain and patient satisfaction were observed in this study: obesity and female sex. Being overweight to the point of obesity and being female increased the risk of a less than satisfactory result. Greater pain responses were noted in both of these groups.
The authors conclude that surgeons should aim for a specific range of correction when treating Blount disease surgically. Both the metaphyseal-diaphyseal angle and the femoral-tibial angle can be used as effective and reliable guidelines for optimal correction. The authors were pleased with the information gathered in this study. They plan to expand their investigation and look more closely at the relationship between surgical results and patient satisfaction. Since the questionnaires were filled out by parents for their children, results may not be the same as if the children completed their own surveys.
Studies like this one conducted some time after the surgery may also be biased by the patient's ability to recall details after surgery that was performed some time ago. Collecting data directly during the recovery and early post-operative phase might yield different (possible even more accurate) findings.
Reference: Jerome K. Jones, MD, et al. Outcome Analysis of Surgery for Blount Disease. In Journal of Pediatric Orthopaedics. October/November 2009. Vol. 29. No. 7. Pp. 730-735.