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 capi-tal femoral epiphysis. When these pins are left in place for a long period, it is very difficult to remove them during total hip arthroplas-ty, 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 oper-ating time is reduced significantly.