The Incidence of Pin Tract Infections and Septic Arthritis in Percutaneous Distal Femur Pinning.

BACKGROUND: Retrograde percutaneous pinning often involves intra-articular pin placement. Classic teaching has cautioned about the risk of septic arthritis with intra-articular pins, although an incidence has not been reported for this complication. The purpose of this study was to determine the incidence of pin tract infections and septic arthritis following retrograde percutaneous pinning of the distal femur. METHODS: A retrospective review identified patients who underwent retrograde percutaneous pinning of the distal femur for osteotomy or physeal fracture fixation at a tertiary pediatric hospital from 2006 to 2017 and had at least 3 months follow-up. The incidence of pin site infections and septic arthritis was determined. RESULTS: In total, 163 patients met criteria, 142 patients with osteotomies and 21 with physeal fractures. The mean pin duration was 33.2±9.0 days (range: 18 to 68 d). Pin duration of ≥30 days was associated with an increased rate of pin tract infections (11.2% vs. 1.4%, P=0.01). The incidence of pin tract infections was 6.7% (11/163), including 9.5% (2/21) in those with fractures and 6.3% (9/142) following osteotomy (P=0.64). There were no cases of septic arthritis. Of the 11 patients with pin tract infections, 9 were treated successfully with oral antibiotics and 2 patients (1.2%) underwent surgical intervention for infection. Treatment of pin infections with oral antibiotics alone was successful in all 7 patients whose pins were removed within 35 days of surgery, but in only 2 of 4 whose pins were removed later (P=0.11). Of the 2 patients who required irrigation and debridement, one had a superficial pin site infection and retained subcutaneous pin and the other had a pin tract abscess and osteomyelitis at the osteotomy site. CONCLUSIONS: Of 163 patients who underwent retrograde percutaneous pinning of the distal femur, no patient developed septic arthritis and the incidence of pin site infections was 6.7% (11/163). Intra-articular retrograde percutaneous pinning of the distal femur is a safe technique with a low risk of septic arthritis. LEVEL OF EVIDENCE: Level III-case-control study.