Total hip arthroplasty in slipped capital femoral epiphysis: a novel technique to remove embedded knowles pins.

The Knowles pin has been well recognized in fixing slipped capital femoral epiphysis. When these pins are left in place for a long period, it is very difficult to remove them during total hip arthroplasty, because the pins have fluted threads, which are oversized in the end and allow bone growth in the previously threaded slots. We present a simple and novel technique to remove Knowles pins so that both unnecessary trauma to the lateral femoral cortex and operating time is reduced significantly.