Letter related to the article “Legg-Calvé-Perthes disease”

Dear Sir,

In the 4/2011 issue of Revista Española de Cirugía Ortopédica y Traumatología, the subject of Perthes disease was addressed in an Update by Drs. Salcedo, González, and Albiñana.

First, may I commend these authors for their efforts and congratulate all of us on the steady improvement in Orthopaedics in Spain and how it is becoming comfortable with the new era. Gone are the years when, here in Spain, we continued to prescribe the various unloading braces, even though they had been abandoned in more advanced countries—as if what was published in international journals made no impression on us.

I would like to clarify several points, however. First, regarding the incidence of the disease, thanks to the data from research presented at the last Congreso de la Sociedad Española de Ortopedia Pediátric held in La Coruña, we can now report that the incidence in Spain is 1.59 cases per 100,000 inhabitants.¹ This research describes the study's population base over the last 16 years (1994–2010) as the population peripheral to Madrid, located in the municipalities of Coslada, San Fernando, Mejorada, and Velilla de San Antonio and ranging from 126,000 to 167,000 inhabitants during these years, where 37 cases of Perthes were diagnosed and, surprisingly, a slow but steady reduction in the incidence of the disease was also noted.

As far as treatment is concerned, more and more cases are being treated surgically because, from lengthy follow-up periods, we know that osteoarthritis of the hip will appear in almost 50% of cases. Given this panorama of poor outcomes, the orthopaedic community around the world has become more inclined toward intervention, hoping to achieve a more spherical and congruent hip at the end of the growth period. In an attempt to favourably alter the natural course of the disease, they are less and less tolerant of “small” joint deformities.

Some surgical techniques that are now in utter disuse were once performed routinely in the majority of cases—adductor tenotomy, for example, which came to be used less and less because it failed to restore mobility in the medium term. Contracture of the hip refers to the involuntary contraction, in response to joint mechanoreceptors, of the entire musculature—not just contracture of the adductor longus. The adductor longus is the most superficial and, therefore, the one most easily detected on palpation. Simply sectioning this muscle does not make the rest of the synergistic musculature relax. Besides, the clinical improvement could be due to the enforced post-operative rest and then the time spent in a rigid abduction system, whether cast or splint.

Tenotomy progresses toward a new contracture—the muscle becomes anchored again, and the contracture reappears. In our 432-case series, 31 of them underwent tenotomy. The indications for it were according to each surgeon's preference but always included an abduction of 20–30° less than the healthy side. The results were that, in 28 cases, improvement lasted a mean of 4.60 months (range 1–12; SD 2.9; mode 3), understanding that the patient was immobilized in a Petrie cast for 1.5 months. In only 2 of the 31 patients did the improvement persist the entire time. In the 1 remaining case, the patient underwent another tenotomy 9 months after the first one, and the contracture again recurred.

Lastly, I would like to comment on the trochanteric epiphysiodesis issue. Shah et al.² recently published research that has changed how we handle trochanteric overgrowth cases.

Traditionally, we surgeons used this slowing technique on patients under 8 years of age, just as the Spanish authors explain. However, this important research from India has established that epiphysiodesis is effective in children older than this. Dr. Shah and colleagues have shown that this technique is effective in 80% of children 8–9 years of age; in 50% of patients between 8.5 and 10 years of age; and in up to 30% of patients 10–11 years old.

It is clear from this data that epiphysiodesis is an effective treatment in children over 8 years of age, as well.