Is it necessary for a buckle fracture of the second phalange index to not only have splint for 4 weeks but 3 additional weeks of no splint & no sports?

Conservative : I'm assuming you are asking about a child's finger. The younger the patient, the faster it will heal. 4 weeks is usually sufficient. However, an additional 3 weeks of buddy taping and perhaps sports avoidance is not unreasonable...Although a bit conservative. If this advice was from an orthopedic surgeon, then i would suggest following these recommendations.