Pharmaceutical compositions in gel form for use in the treatment of postoperative pain, comprising or consisting of a hydrophilic matrix consisting of a hyaluronic acid derivative containing an amide local anaesthetic in base form, and optionally containing pharmaceutically acceptable excipients, wherein the hyaluronic acid derivative is selected from: • autocrosslinked derivatives obtained by internal esterification, with a degree of esterification not exceeding 20%, and prepared from HA with a weight average MW ranging between 160 and 230 kDa, preferably 200 kDa in a concentration between 10 and 40 mg/ml; • crosslinked derivatives obtained by using crosslinking agents such as BDDE (1,4-butanediol diglycidyl ether) with a degree of derivatisation ranging between 2.5 and 25% molar, relative to the repeating unit of hyaluronic acid, and prepared from HA with a weight average MW ranging between 500 and 730 kDa, in a concentration between 10 and 40 mg/ml; • amide derivatives obtained by amidation of the carboxyl groups of hyaluronic acid and the amino groups of amines of the aliphatic, arylaliphatic, cycloaliphatic, aromatic, cyclic and heterocyclic series, with a degree of amidation ranging between 0.1 and 50% molar, and prepared from HA with a weight average MW ranging between 500 and 730 kDa, in a concentration between 5 and 15 mg/ml; and the amide local anaesthetic is selected from bupivacaine, etidocaine and ropivacaine in concentrations between 10 and 35 mg/ml. wherein the hyaluronic acid derivative is selected from: • autocrosslinked derivatives obtained by internal esterification, with a degree of esterification not exceeding 20%, and prepared from HA with a weight average MW ranging between 160 and 230 kDa, preferably 200 kDa in a concentration between 10 and 40 mg/ml; • crosslinked derivatives obtained by using crosslinking agents such as BDDE (1,4-butanediol diglycidyl ether) with a degree of derivatisation ranging between 2.5 and 25% molar, relative to the repeating unit of hyaluronic acid, and prepared from HA with a weight average MW ranging between 500 and 730 kDa, in a concentration between 10 and 40 mg/ml; • amide derivatives obtained by amidation of the carboxyl groups of hyaluronic acid and the amino groups of amines of the aliphatic, arylaliphatic, cycloaliphatic, aromatic, cyclic and heterocyclic series, with a degree of amidation ranging between 0.1 and 50% molar, and prepared from HA with a weight average MW ranging between 500 and 730 kDa, in a concentration between 5 and 15 mg/ml; • autocrosslinked derivatives obtained by internal esterification, with a degree of esterification not exceeding 20%, and prepared from HA with a weight average MW ranging between 160 and 230 kDa, preferably 200 kDa in a concentration between 10 and 40 mg/ml; • crosslinked derivatives obtained by using crosslinking agents such as BDDE (1,4-butanediol diglycidyl ether) with a degree of derivatisation ranging between 2.5 and 25% molar, relative to the repeating unit of hyaluronic acid, and prepared from HA with a weight average MW ranging between 500 and 730 kDa, in a concentration between 10 and 40 mg/ml; • amide derivatives obtained by amidation of the carboxyl groups of hyaluronic acid and the amino groups of amines of the aliphatic, arylaliphatic, cycloaliphatic, aromatic, cyclic and heterocyclic series, with a degree of amidation ranging between 0.1 and 50% molar, and prepared from HA with a weight average MW ranging between 500 and 730 kDa, in a concentration between 5 and 15 mg/ml; and the amide local anaesthetic is selected from bupivacaine, etidocaine and ropivacaine in concentrations between 10 and 35 mg/ml. <EOS>