PHYSEAL BAR-CT

Case Details

 5 years old boy presented for CT scan with leg length discrepancy with reduced length of right leg with old history of infection in the right knee region ( old details or imaging was not available). MDCT for knee joint with lower femur showed- reduced length of right leg in scanogram & irregular distal right femoral physis. Irregular bony bridging in the central part of the distal growth plate of right femur involving about 50% of the growth plate causing its obliteration with residual unfused growth plate along the periphery- suggesting physeal bar.

Teaching Points by Dr MGK Murthy, Dr GA Prasad

Technologist: Mr Farooq

Physeal bar - Bone bridge obliterating  growth-plate cartilage of bone casing premature  growth arrest of bone. Most frequently posttraumatic in children , other causes- infection, ischemia, tumoral invasion, and radiation. Most common sites of growth arrest include the distal tibia, distal femoral and distal ulnar physis.

Types –

1. central type -  growth of bone  is slowed or stopped and limb shortening occurs.
2. Peripheral type-  growth is tethered and angular deformity of bone develops

Premature physeal bony bridging in children is most often posttraumatic and disproportionately involves the distal tibia and femur where bridges tend to develop at the sites of earliest physiologic closure - anteromedially and centrally, respectively.

MRI -  Larger bridges tend to be of high signal intensity on T1-weighted images, whereas smaller bridges have variable signal intensity. T1-weighted images also ideally reveal growth recovery lines that indicate differential physeal growth. Intermediate- and T2-weighted images best reveal associ ated metaphyseal cartilage extensions. Gradient-recalled imaging optimally depicts the bridge as a low-signal-intensity interruption in otherwise high-signal-intensity physeal cartilage. The volumetric fat-suppressed 3D spoiled gradient-recalled echo sequence allows accurate mapping of the physeal bone bridges that appear as low-signal-intensity areas within the otherwise high-signal-intensity physis

Surgical treatment depends on the bridge size and location.  Resection is indicated if less than 1/3 to 1/2 of growth plate is involved. Larger bridges often require ipsilateral, contralateral, or combination epiphysiodesis (surgical physeal fusion). Angular deformities are corrected with osteotomies

Younger children tend  to have a better prognosis with  resection than older children.

Less than 2 years of remaining growth is a relative contra-indication for bone bridge resection.

Central bars are more amenable to resection than peripheral bars.

Ischemic or septic related bone bars have a poor prognosis with resection.