What outcomes compare one vs two distal screws for humerus nails?

The retrieved evidence does not directly compare one versus two distal screws for humerus nails, so no firm rule can be drawn from it.

The closest biomechanical finding comes from a 2025 study on antegrade humeral shaft nailing, which reported that two distal screws increased compressive stiffness compared to one [1]. That same study found a 5 cm distance between fracture and distal screws improved axial and torsional stability [1]. But it tested shaft fractures, not posterior humerus fractures, and used a nail, not a short pin. The mechanics of a short pin in a posterior fracture differ: working length, bone quality at the distal site, and rotational forces are not the same.

No retrieved study compared one versus two distal screws for posterior humerus fractures specifically. No study reported nonunion, implant failure, or reoperation rates for that construct. The evidence base here is thin and does not cover the exact question.

The decision should rest on fracture stability, bone quality, and surgeon judgment, not a universal rule. The evidence supports two screws for added stiffness in shaft fractures, but does not prove it is always necessary for posterior fractures.

My call: no evidence in this retrieval justifies a rule that a short pin in a posterior humerus fracture must always have two distal screws. Confidence: low, because the evidence does not cover the specific construct.