No abstract

In situ percutaneous pinning of a Slipped Capital Femoral Epiphysis (SCFE) is a safe and effective surgical treatment to prevent deformity progression in children.1 Implant options for “pinning” include Kirschner wires, Knowles pins, but more commonly, cannulated fully and partially threaded screws. Cannulated screws exist with various designs available in both stainless steel or titanium. Routine implant removal after termination of growth around puberty is controversial. Some surgeons perform removal to reduce risk of fracture associated with an increased stress riser, reduce risk of trochanteric bursitis, or accommodate secondary hip procedures such as future arthroplasty.2,3,4 A rarer indication for removal is one out of necessity for correctional osteotomies in the treatment of chronic symptomatic SCFE deformity. Difficulty with hardware removal is well documented in SCFE patients.4–8 Most commonly noted are cases of a lodged and stripped screw that is not retrievable via standard method of screw reversal.7,5,9,10 The challenges of removal as well as the underlying causes have been studied, implicating metal type and some parameters of thread design.9 Screw manufacturers responded with development of harder, smoother metals to prevent ingrowth with the addition of reverse cutting threads to aid in backing out.11 Some surgeons describe their own means of responding to the problem by either leaving retained hardware, hollow milling to permit engagement with vice grips, and over reaming to the level of the proximal threads.9 In this article we describe our technical tips for removal of a stuck 7.0 cannulated cancellous SCFE screw that was lodged in a patient who required surgical hip dislocation, femoral neck osteoplasty, and relative femoral neck lengthening for treatment of her chronic SCFE deformities 38 months from implantation. We describe screw removal failure that ultimately required over reaming with a 10 mm coring reamer to retrieve the screw. A written and video technical guide is provided for evaluating the opportunities and obstacles of how similar cases can be addressed with similar success.