This blog looks at two of the specific hip conditions that affect youngsters and that I manage in my children’s orthopaedic practice.
Perthes disease, a hip disorder in young children, is defined as idiopathic (unknown cause) avascular necrosis (disruption of the blood supply) of the capital femoral epiphysis. (top part of the ball of the growing hip joint) See picture 1)
Picture 1a – Pelvis X-ray showing Perthes left hip
First described around 1910 independently be 3 surgeons, Legg, Calve and Perthes, it was perhaps Waldenstrom who did the majority of the early research into this curious condition. Over one hundred years on today, it's exact aetiology (cause) remains unknown and the various treatment options are often hotly debated in paediatric orthopaedic meetings around the world.
What is known in the UK is that the incidence seems to be on the decline, with 1 approximately in 10,000 new cases per year. More common in boys (x4) it typically presents between 4 and 8 years of age and tends to be more common in active children.
A vascular (blood supply) insult to all, or part of the dome shaped growing part of the femoral head (epiphysis) causes osteonecrosis, (cell death) which then with mechanical load causes the head to collapse and fragment at the top part of the ball. Over time as the body heals itself, the blood supply will reconstitute to that area and reossification (new bone formation) is then followed by remodelling. This whole pathological and healing process can take from 18 months to 2 years. I tell my patients and their families the analogy of the hip being similar to a brick building with a dome shaped roof. Someone comes along and starts taking lots of random bricks out (like a giant game of Jenga®) The idea of management is to keep the roof a dome shape, and stop it from caving in as the bricks will be replaced when the blood supply comes back and the bone heals.
Children usually present with a painless limp, but symptoms can fluctuate and be very subtle, (mild thigh or knee ache). Any child with reduced range of movement of the hip, particularly internal rotation should be sent for plain X ray's. (pictures 2a &2b)
Pictures 2a & 2b showing the internal and external rotation examination of a childs hip
There are numerous classification systems available which suggests not one is superior or used universally to guide management.
Treatment goals include pain relief, (analgesics, anti-inflammatories and activity restriction) maintaining range of motion (physiotherapy and/or hydrotherapy) and containment of the femoral head within the acetabulum (socket). This can sometimes involve surgery to reshape the ball or the socket (femoral or pelvic osteotomies).
The ultimate aim is a round head in a round socket at skeletal maturity, so that the risk of early arthritis and hence the need for a total hip replacement is minimised.
At present there remains no good randomised controlled trials (RCTs) of current treatments to guide best practice.
Slipped upper femoral epiphysis (SUFE) remains a challenging condition to treat. The terminology is actually misleading as it's actually the metaphysis (neck) that slips, as the epiphysis maintains its normal anatomical relationship within the acetabulum. (socket)
Unlike Perthes, the incidence of SUFE is almost certainly on the increase, most likely related to increasing childhood obesity, not only in the UK but worldwide.
The overall incidence is slightly less than Perthes, but it's still more common in boys than girls.
The exact cause of SUFE is still unknown but most likely is multifactorial with mechanical, hormonal and genetic factors all playing a role in its development.
Clinical symptoms of SUFE, can also be subtle and the diagnosis, unfortunately is sometimes delayed. Examination findings reveal an externally rotated foot position and again limitation or pain with internal rotation. A frog lateral pelvic x-ray remains the gold standard in diagnosis. (See picture 3)
Picture 3 Frog lateral X-Ray showing SUFE of left hip
SUFE is generally classified into its stability (the ability to weight bear through the affected side) and it's chronicity. (timing of symptoms) Avascular necrosis remains the most terrible and devastating complication of this condition. Adolescents with unstable slips, of the more acute nature are most at risk of this.
Traditionally treatment after diagnosis, has involved in situ screw fixation of the slip to prevent further slip and then, depending on the remodelling potential the possibility of performing a later subtrochanteric osteotomy (realignment operation) to tackle residual deformity.
Picture 4 – X-Ray showing in situ screw fixation of a mild slip
More recently, there has been real interest in an earlier surgical approach, realigning the slip via a controlled open dislocation of the hip which carefully preserves the blood supply. This acute subcapital realignment osteotomy and fixation, restores near anatomical relationships at the outset. See Picture 5. The technique has received mixed reviews in the paediatric orthopaedic world. Here in Reading we have developed a niche specialist interest in this technique, as I became interested and experienced in this surgery on my fellowship to Sydney, Australia. We now have a reasonable cohort of patients in Reading who have undergone this procedure, with the vast majority showing excellent results. We are the regional centre for our ROSPOG (Regional Oxford and Southampton Paediatric Orthopaedic Group) network and patients travel to Reading for consideration of this surgery if appropriate for their care.
Picture 5a – X ray showing severe right slip 5b – fixation after open dislocation
The BOSS study (British Orthopaedic surgery surveillance study) is an exciting new development in the field of paediatric orthopaedics and is being lead by Mr Dan Perry (childrens’ orthopaedic specialist) and his research team from the University of Liverpool. It's an all inclusive nationwide reporting mechanism to determine the true epidemiology and present outcomes in rare orthopaedic diseases. Every hospital in the country treating these 2 conditions have been collecting valuable information on their patients. By collating this information it will allow us to enable a better understanding of these conditions, and to hopefully in the future, drive the development of RCTs. In Reading we have been recruiting all our hip patients into this study. For more information please see the informative website: www.boss.surgery
Are you a GP, physio or other healthcare professional? If you would like Mr Davies to visit your practice to talk about Kids Hips or any other area of paediatric orthopaedics or adult knee surgery please contact us directly.
If you or a family member under 16 have an orthopaedic problem Nev can see you either through his NHS practice at The Royal Berkshire Hospital – (you will need a referral from your GP) or privately via his secretary Debbie Rollason on 07305097137 or via e mail on firstname.lastname@example.org