Spontaneous rupture of flexor tendons, lower leg

Not billableICD-10-CM diagnosis code.

This code exists but cannot be submitted on its own. It groups the more specific codes beneath it.

A category header for its whole life, FY2016 onwards. It has never been valid for submission on its own.

Submit one of these 3 more specific codes instead:

M66.361 Spontaneous rupture of flexor tendons, right lower leg
M66.362 Spontaneous rupture of flexor tendons, left lower leg
M66.369 Spontaneous rupture of flexor tendons, unspecified lower leg

What has happened to this code

Every change the publisher made, from 2012 to now. Entries marked draft are from the pre-implementation releases: ICD-10 took effect on 1 October 2015, so nothing before FY2016 was ever valid on a claim.

FY2012 Added to the draft code set draft Spontaneous rupture of flexor tendons, lower leg

Official coding rules

Published by CDC for FY2027. A rule attached to a category binds every code beneath it, so the rules inherited from this code's ancestors are shown with the code they come from.

Inherited from M66 Spontaneous rupture of synovium and tendon

Excludes2 - not included here

rotator cuff syndrome (M75.1-)
rupture where an abnormal force is applied to normal tissue - see injury of tendon by body region

Includes

rupture that occurs when a normal force is applied to tissues that are inferred to have less than normal strength

How CDC's index refers to this code

Wording from the official alphabetic index. Much of it appears nowhere in the code description, which is why a search for the everyday phrase so often finds nothing.

Sloughing > tendon
Slipped, slipping > tendon
Disorder > tendon > rupture
Disease, diseased > tendon, tendinous
Rupture, ruptured > musculotendinous junction NEC, nontraumatic
Rupture, ruptured > tendon > nontraumatic > flexor > lower leg

Codes in the same group

Code	Description	Status
M66.30	Spontaneous rupture of flexor tendons, unspecified site	Valid
M66.31	Spontaneous rupture of flexor tendons, shoulder	Not billable
M66.32	Spontaneous rupture of flexor tendons, upper arm	Not billable
M66.33	Spontaneous rupture of flexor tendons, forearm	Not billable
M66.34	Spontaneous rupture of flexor tendons, hand	Not billable
M66.35	Spontaneous rupture of flexor tendons, thigh	Not billable
M66.37	Spontaneous rupture of flexor tendons, ankle and foot	Not billable
M66.38	Spontaneous rupture of flexor tendons, other site	Valid
M66.39	Spontaneous rupture of flexor tendons, multiple sites	Valid