You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["AnatomicalEntity"].

Please return the output as a JSON object of the format: {"AnatomicalEntity": ["tumor cells", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Complications after plate fixation of phalangeal fractures.
PURPOSE:
To assess the complications after plate fixation of phalangeal fractures, their correlation with the type of injury, and the outcome.
METHODS:
We retrospectively reviewed the clinical records and the x-rays of 54 consecutive patients with 64 phalangeal fractures treated by open reduction and plate fixation with regard to fracture healing, plate loosening or failure, infection, complex regional pain syndrome, pain, return to work, and range of motion.
RESULTS:
In 31 out of 54 patients (57%) and 33 out of 64 fractures (52%), one or more major complications occurred. Stiffness (definition is composite range of motion of metaphalangeal, proximal interphalangeal, and distal interphalangeal joints added together equaling <180 degrees) contributed the highest number (22 patients, 24 fractures). The complication rates were not different whether the fracture was open or closed, if it was located in the proximal or middle phalanx, the presence or absence of an associated soft tissue lesion, and the patient's occupation.
CONCLUSIONS:
In spite of early mobilization, stiffness is the most frequent complication after open reduction and plate fixation of phalangeal fractures. The undue amount of scarring and adhesion may arise from the implant itself or the difficulty in finding the perfect mixture between the minimal surgical invasiveness and a sufficient restoration of skeletal stability. Otherwise, plate fixation of unstable and complex phalangeal fractures proved efficient and reliable, although not free of potential problems.
{"AnatomicalEntity": ["middle phalanx", "skeletal", "proximal interphalangeal", "distal interphalangeal joints", "metaphalangeal", "phalangeal", "soft tissue lesion"]}