What is Hemiephysiodesis?

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Patient Presentation
A new 14-year-old male came to clinic after moving to the area for concerns for increasingly being knock-kneeded. He and his parents had noticed it more over the past couple of years as he had become more active in school activities. He looked more awkward running and he had increased shoe wear. He occasionally would fall but parents didn’t think it was more often than others and always occurred with a physical activity. The past medical history showed mild intellectual disability without cerebral palsy or other co-morbidities. The family history was negative for musculoskeletal problems but there was a family history of mild intellectual disability on both sides of the family. The review of systems was negative.

The pertinent physical exam showed a healthy male with normal vital signs. His height was 161 cm (75%) and weight was 60.2 kg (95%). With standing and forward-bend test there was no scoliosis. With standing, the hips appeared to be symmetric in height. The distances between the ipsilateral iliac crest to lateral malleolus was the same bilaterally. The distances between the contralateral iliac crest and medial malleolus were also the same. With both patellas facing forward he stood with knees together and there was obvious genu valgum with the intramalleolar distance being 31.5 cm. There was no pain and full range of motion in his lower extremities. He had flexible pes planus bilaterally. Inspection of his shoe soles showed more wear on the medial surfaces bilaterally.

The diagnosis of genu valgum without an obvious cause including leg length discrepancy was made. The patient was referred to orthopaedics who offered the family the options of continued monitoring, hemiephysiodesis (i.e. guided growth) with tension plates or other hardware. They did not recommend osteotomy. The patient and family chose hemiephysiodesis with tension banding. At followup for his well child health supervision visit, he reported some minor pain initially after surgery which improved with physical therapy and was doing well currently. He had a followup surgery appointment in another 2 months.

Discussion
Angular deformities of the lower extremities are common problems and can be idiopathic, congenital or acquired. Idiopathic knee deformities are usually managed by monitoring and family reassurance as these often improve with time or are minimal and do not cause problems. Those ≤ 10 degrees are considered non-problematic. Genu varus usually peaks between 1-3 years and if problematic can cause waddling gait, lateral thrust and ligamentous laxity. Genus valgus usually peaks around 3-6 years and if problematic can cause circumduction gait, anterior knee pain and patellofemoral instability.

Treatment options are meant to improve alignment.

  • Osteotomy is usually considered the gold standard but has many potential complications including potential need for revision, immobilization, potential hospitalization, pain, increased recovery time, compartment syndrome and other risks of neurovascular complications.
    Many view it as a secondary or tertiary option for patients needing angular correction whose physis is still open.

  • Partial physeal ablation – this is a permanent technique and problems can include difficulty in performing the procedure, delay in bone bridge formation and it may not work adequately.
  • Blount’s stapling was introduced in 1949 using heavy staples/wires to fix the physis unilaterally but to guide the growth of the physis. The hardware can break or migrate and therefore may not be as helpful.

Learning Point
Hemiepiphysiodesis is also known as guided growth. This surgical technique temporarily fixes one side of the physis, thus allowing normal growth to be guided and the limb’s angular deformity corrected over time in skeletally immature patients. Partial physeal ablation and Blount’s stapling are types of hemiepiphysiodesis.

In 2007 Dr. Peter Stevens published a paper on the use of a new hemiepiphysiodesis system using a tension band plate (now known as eight-Plate®). The plate looks like a the number 8, and is attached extraperiostally across a physis by two screws. In varus deformities the plate is attached on the lateral side, and in valgus deformities it is attached on the medial side. Patients are then monitored and once correction is achieved, the plate is removed. Outcomes for a variety of conditions including idiopathic, Blount’s disease (i.e. genu vara), dysplasias, exostoses, etc. have been very good with fewer problems. Those with an incomplete treatment usually have some significant improvement of the problem. The system is being used in patients of different age ranges also. Correction is reportedly faster in idiopathic cases than in those that are congenital or acquired. Patients often after surgery are easily controlled with minimal pain medication, no crutch or minimal crutch use and a quick return to activities. A followup study did find that for patients who are older (adolescents), have more plates implanted, had femoral plates or had bilateral fixation, do have higher chances of needing more types of physical therapy and delayed return to activities. However, these delays are usually much less than required for other types of surgery particularly osteotomy.

A picture of the system from the company can be found here.

Questions for Further Discussion
1. How do you perform the physical examination for genu varus and valgus?
2. How common is Blount’s disease?
3. What are indications for referral to physical therapy?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for this topic: Leg Injuries and Disorders

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Stevens PM. Guided growth for angular correction: a preliminary series using a tension band plate. J Pediatr Orthop 2007; 27:253-259.

Boero S, Michelis MB, Riganti S. Use of the eight-Plate for angular correction of knee deformities due to idiopathic and pathologic physis: initiating treatment according to etiology. J Child Orthop. 2011 Jun;5(3):209-16.

Fillingham YA, Kroin E, Frank RM, Erickson B, Hellman M, Kogan M. Post-operative delay in return of function following guided growth tension plating and use of corrective physical therapy. J Child Orthop. 2014 May;8(3):265-71.

Heflin JA, Ford S, Stevens P. Guided growth for tibia vara (Blount’s disease). Medicine (Baltimore). 2016 Oct;95(41):e4951.

Welborn MC, Stevens P. Correction of Angular Deformities Due to Focal Fibrocartilaginous Dysplasia Using Guided Growth: A Preliminary Report. J Pediatr Orthop. 2017 Apr/May;37(3):e183-e187.

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

Published