Convert to ICD-10-CM: 
724.71 converts approximately to:
- 2015/16 ICD-10-CM M53.2X8 Spinal instabilities, sacral and sacrococcygeal region
 
 ICD-9-CM Volume 2 Index entries containing back-references to 
724.71:
- Hypermobility
coccyx 724.71
 - Movable
coccyx 724.71