Final answer:
The most common reason for failed compartment release surgery for DeQuervain's is inadequate release of the first dorsal compartment. Other reasons can include scar tissue formation and misdiagnosis, as well as complex medical conditions like rheumatoid arthritis.
Step-by-step explanation:
The most common reason for failure of compartment release surgery for DeQuervain's tenosynovitis is inadequate release of the first dorsal compartment. This surgical treatment is aimed at relieving the pain and inflammation associated with DeQuervain's, which affects the tendons on the thumb side of the wrist. If the sheath surrounding the tendons is not fully released, the tendons continue to rub against it, leading to persistent symptoms. Other potential reasons for failure include scar tissue formation, misdiagnosis resulting in surgery on a non-affected compartment, or a complex medical presentation where DeQuervain's is secondary to another condition such as rheumatoid arthritis.