Infection of extensor tendons rarely results in loculated<unk> , but disruption of normal flexor tendon function can be dangerous as it may spread proximally involving the wrist/forearm (Parona space). It is an surgical/orthopedic emergency!
Infectious tenosynovitis
Calcaneal bursitis
Calcific tendinitis
Septic bursitis
Olecranon bursitis 
Flexor tenosynovitis
Prepatellar bursitis 
Pes anserine bursitis