Hydrogels for orthopedic repair

A composition for forming a water-absorbing, high modulus polymeric, hydrogel-forming material comprising at least one macromer and at least one monomer,

• wherein the macromer comprises hydrophobic and hydrophilic regions, has a molecular weight of 1000 to 100,000 Da and has at least two covalently polymerizable groups, and the macromer comprises at least 5% (wt/wt) of the composition,
• wherein the monomer contains at least one ethylenically unsaturated group and has a molecular weight of less than 1,000 Da, and
• wherein the monomer comprises at least 30% (wt/wt) of the composition, and
• wherein the composition forms a gel upon polymerization, and wherein the gel is characterized as having the following properties,
• a) absorbing water to less than 300% of its initial weight, on equilibration with water or body liquids;
• b) having a tensile modulus of at least 500 kPa or greater at equilibrium swelling with an aqueous solution
• b) having a solids content of at least 20% after equilibration in water or bodily liquids,
• c) having an elongation to failure of at least 25% at hydration equilibrium;
• and
• d) being sufficiently biocompatible to permit the treatment or repair of biological tissue, or used as an implant in a patient.