A study of 21 cases of sewing needle fragments accidentally broken off in and about the knee joint demonstrates a uniform mechanism of injury. Penetration occurs with the patient kneeling on a carpet into which the needle has lodged. The needle is broken by the sudden extension of the knee in reaction to the pain. Full appreciation of the mechanism of injury should all but eliminate major difficulty (nine of the 21 cases in this series) in surgical recovery of the retained needle fragment.
Ramsey RH, Goodman FG. The Sewing Needle and the Knee. JAMA. 1967;199(1):23-25. doi:10.1001/jama.1967.03120010067013