Mezue ahịrịokwu na-esonụ: N'oge na-esote oge Karlsson na-egwuri egwu na mba Sweden n'okpuru afọ 18 na 1982 IIHF European U18 Championship, na-enweta isi ihe abụọ na egwuregwu ise ma merie nrite ọlaedo. Karlsson na-egwuri egwu na Sweden si n'okpuru-20 mba otu na 1983 nakwa
1984 World Junior Ice Hockey Championship. N'oge 1982/83, e nyere Karlsson ohere igwu egwu na Modo Hockey nke Elitserien, otu egwuregwu ice hockey kacha elu na Sweden. N'ime oge abụọ mbụ ya na ndị otu ahụ, ọ nweghị ike ịme ihe mgbaru ọsọ ọ bụla, na n'oge 1983-1984 ndị otu ahụ dara na Ngalaba 1. Agbanyeghị, a kwalitere Karlsson na Modo ngwa ngwa na Elitserien n'oge na-esote.