Compositions for bone repair have been developed based on linear hydrophobic degradable polymers and monomers or macromers, at least one of which includes an anhydride linkage. The monomers and/or macromers crosslink each other but not to the linear polymer to form semi-interpenetrating networks. The compositions can include various excipients, therapeutic and/or diagnostic agents. The compositions can be polymerized in the presence of dissolvable particles such as inorganic salts and proteinaceous materials to provide a porous polymer network. The compositions can be injected into a patient and polymerized in situ or can be polymerized ex vivo and implanted. When polymerized ex vivo, the composition can be shaped into various articles, such as pins, screws, and hollow tubes, which can be used to repair broken bones.