A guide tool for guiding surgical instrumentation and facilitating insertion of surgical implants for repair of cartilage and/or bone damage and/or for remodeling of a joint surface for improved mobility in a finger or toe joint is disclosed. The guide tool includes an attachment part including a patient specific contact surface adapted to fit the proximal phalanxes or metatarsal bones in a toe or the distal-, middle-, or proximal phalanxes or metacarpal bones in a finger and further including a directing flange. A design model designing a guide tool described above and the use of the instruments are also disclosed.