ICD-10 Code S62.351P: Metacarpal Fracture Malunion Guide

Key Takeaways

S62.351P is a billable ICD-10-CM code for a nondisplaced fracture of the shaft of the second metacarpal bone, left hand, at a subsequent encounter where fracture healing has resulted in malunion.

The 7th character P specifically means the bone has healed in an abnormal position, distinguishing it from D (routine healing), G (delayed healing), K (nonunion), and S (sequela).

Selecting the wrong 7th character suffix is a leading cause of claim denial on subsequent encounter fracture visits; documentation must explicitly support malunion before assigning P.

Pabau’s claims management software helps orthopedic and hand surgery practices reduce coding errors and track subsequent-encounter fracture claims through a single workflow.

Most claim denials on subsequent metacarpal fracture visits come down to one thing: the wrong 7th character. A coder assigns D for routine healing, the radiograph says otherwise, and the documentation never caught up. ICD-10 Code S62.351P exists precisely for this scenario. It captures a patient returning for follow-up care on a second metacarpal shaft fracture of the left hand where healing has progressed to malunion, a position-specific complication that requires deliberate documentation and careful code selection. This reference guide covers the full clinical description, 7th character conventions, adjacent code comparisons, and practical billing guidance for coders and clinicians managing these cases.

This code applies to encounters on or after October 1, 2015, the date CMS mandated the transition to ICD-10-CM for all covered transactions under HIPAA. It remains valid for FY2026 and is indexed under the S62 parent category, Fracture at wrist and hand level, maintained by the CDC’s National Center for Health Statistics.

ICD-10 Code S62.351P: Full description and code structure

ICD-10 Code S62.351P has an official full description of: Nondisplaced fracture of shaft of second metacarpal bone, left hand, subsequent encounter for fracture with malunion.

Breaking this down into its clinical components helps coders and clinicians verify they have the right code before submitting a claim.

• Nondisplaced: The fracture fragments remained in anatomical alignment at the time of injury. The bone broke but the two ends did not shift out of position relative to each other.
• Shaft of second metacarpal bone: The diaphysis (mid-portion) of the index finger metacarpal, not the base, neck, or head. Coders must confirm the fracture location in the operative or clinical note.
• Left hand: Laterality is explicitly encoded. The equivalent right-hand code is S62.350P. Never assign S62.351P for a right-hand injury.
• Subsequent encounter: The patient is being seen after definitive treatment has been established. The initial encounter codes (A for closed, B for open) should no longer be used once active treatment has begun and the patient is returning for follow-up.
• Malunion: The fracture has healed, but in an abnormal position, angulated, rotated, or shortened in a way that may cause functional impairment.

S62.351P sits within the ICD-10-CM hierarchical structure: S00-T88 (Injury, poisoning and certain other consequences of external causes) > S60-S69 (Injuries to the wrist, hand and fingers) > S62 (Fracture at wrist and hand level) > S62.3 (Fracture of other metacarpal bone) > S62.35 (Nondisplaced fracture of shaft of second metacarpal bone, left hand). The 7th character P is appended to complete the code.

Understanding the 7th character P: ICD-10 Code S62.351P in context

The 7th character in ICD-10-CM injury codes encodes the episode of care and the nature of healing. For fracture codes in the S-chapter, this character carries significant billing weight because payers use it to validate that the treatment billed matches the documented stage of recovery. Selecting the wrong character is a coded billing error, not just a documentation oversight.

Per the WHO ICD-10 classification framework and the ICD-10-CM Official Guidelines (Section I.C.19), the full 7th character set for S62.351 is:

The key clinical distinction that separates P from K: malunion means the bone has healed, just incorrectly. Nonunion means healing has not occurred. Radiographic evidence is required to support either designation. Document the imaging findings explicitly in the clinical note; “fracture with malunion confirmed on X-ray dated [date]” is the minimum documentation standard most payers expect.

Malunion vs. nonunion: getting ICD-10 Code S62.351P right

Confusing S62.351P (malunion) with S62.351K (nonunion) is among the most common coding errors on metacarpal fracture follow-up claims. The two conditions are clinically and radiographically distinct, and payers treat them differently for medical necessity review.

Malunion (S62.351P)

The fracture site has bridged with callus and achieved union, but in an angulated, rotated, or shortened position. The patient may present with grip weakness, rotational deformity of the index finger, or pain with axial loading. Treatment at this stage often involves corrective osteotomy rather than re-immobilization.

Nonunion (S62.351K)

The fracture site has not bridged with bone. Imaging shows a persistent fracture gap, sclerotic fracture ends, or absence of bridging callus. Treatment commonly involves bone grafting, intramedullary fixation, or stimulation devices. Use S62.351K, not P, when the operative or imaging report supports a failure-to-heal diagnosis.

Practices managing hand fracture follow-up within physical therapy practice management software benefit from structured documentation prompts that capture imaging findings at every subsequent visit, reducing the risk of defaulting to D when P or K is more accurate. Similarly, sports medicine clinic software that integrates clinical notes with billing can flag when a patient has had multiple subsequent encounter visits without a documented healing status update.

Adjacent and related ICD-10 codes for second metacarpal fractures

S62.351P belongs to a closely related family of codes. Understanding the adjacent codes prevents laterality errors, fracture-type mismatches, and incorrect body-part assignments. Use the AAPC Codify ICD-10-CM lookup to verify adjacent codes when building your code set for a claim.

Note that S62.3 covers fractures of “other” metacarpal bones (second through fifth). The first metacarpal (thumb) has its own dedicated code range under S62.2. Always confirm which metacarpal is fractured from the clinical record before selecting within the S62.35x family.

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Documentation requirements for billing S62.351P

Payers reviewing a claim coded with S62.351P will look for documentation that confirms three things: the patient is being seen at a subsequent (not initial) encounter, the fracture is located in the shaft of the second metacarpal of the left hand, and the healing outcome is malunion rather than routine union, delayed healing, or nonunion.

Imaging documentation

Radiographic confirmation is the foundation of a malunion diagnosis. The clinical note or operative report should reference the specific imaging study (X-ray, fluoroscopy, or CT scan), the date it was performed, and the findings that support malunion, such as angular deformity greater than accepted thresholds, rotational malalignment, or shortening. A note that reads “fracture healing, malunion” without referencing supporting imaging is insufficient for most payer audits.

Practices using patient record management tools that link imaging results directly to the clinical encounter note have a structural advantage here. When imaging findings are embedded in the same record as the visit note, coders can confirm the radiographic basis for P without hunting across separate systems. Pair that with digital clinical documentation that captures standardized fracture follow-up fields, and the documentation chain becomes audit-ready by default.

Clinical note elements

• Explicit statement that this is a follow-up (not initial) visit for the fracture
• Reference to the specific bone and laterality (second metacarpal, left hand)
• Imaging findings describing the malunion (angulation, rotation, shortening measurements where applicable)
• Clinical assessment linking the imaging findings to the diagnosis of malunion
• Treatment plan or next steps (observation, surgical intervention, physical therapy referral)

For practices handling other ICD-10 diagnostic codes alongside fracture coding, structured documentation templates reduce the cognitive load on providers during follow-up visits and help ensure the note supports whatever 7th character the coder ultimately assigns.

Billing and reimbursement notes for ICD-10 Code S62.351P

S62.351P is a billable, specific ICD-10-CM code. Claims with a date of service on or after October 1, 2015 must use ICD-10-CM rather than ICD-9-CM for reimbursement. S62.351P is valid for FY2026 claims.

Medicare considerations

Medicare covers medically necessary services for fracture malunion when documentation supports the diagnosis and the billed procedure. There is no categorical Medicare exclusion for S62.351P, but Local Coverage Determinations (LCDs) and payer-specific policies govern what procedures are reimbursable at a subsequent encounter with malunion. Always check the applicable LCD for orthopedic and hand surgery services in your Medicare Administrative Contractor (MAC) region before assuming coverage. Compliance management tools that flag LCD requirements against specific diagnosis codes help prevent submissions that fall outside covered indications.

CPT code crosswalk

S62.351P is a diagnosis code and must be paired with an appropriate CPT procedure code on the claim. Common CPT codes paired with subsequent encounter metacarpal malunion diagnoses include:

• 26565: Osteotomy, metacarpal, each bone (corrective surgery for malunion)
• 26600-26615: Fracture treatment codes (manipulation and casting, may apply to ongoing management)
• 97110, 97530: Therapeutic exercise and therapeutic activities (physical/occupational therapy at subsequent encounter)
• 99213-99215: Office or outpatient evaluation and management codes (routine follow-up visit with documented assessment)

The diagnosis code S62.351P must be medically necessary to support whichever CPT code is billed. Coders handling injury-related ICD-10 coding across specialties know that diagnosis-procedure medical necessity crosswalks are a key pre-submission check. Use a claims management system that validates CPT-to-ICD-10 pairing before the claim leaves the practice.

Avoid these common billing errors

• Assigning S62.351A (initial encounter) at a follow-up visit after definitive treatment has been established
• Using S62.351P without radiographic documentation of malunion
• Confusing S62.351P (malunion) with S62.351K (nonunion) when imaging shows a persistent fracture gap
• Failing to update the 7th character across visits as healing status changes
• Applying left-hand codes to right-hand injuries (or vice versa)

Practices that invest in claims management workflows reduce these errors systematically rather than catching them only during denial management. Building the 7th character selection into the documentation workflow, rather than leaving it to a post-visit coding review, is the most reliable prevention strategy.

Code history, effective dates, and regulatory context

The ICD-10-CM classification system became mandatory for U.S. reimbursement claims effective October 1, 2015, replacing ICD-9-CM for all covered entities under HIPAA. S62.351P has been valid since that transition and remains current through FY2026. No changes to this specific code have been announced for the FY2026 update cycle.

ICD-10-CM is maintained jointly by the CDC’s National Center for Health Statistics and CMS, with annual updates effective each October 1. The WHO’s ICD-10 framework provides the international classification foundation from which the Clinical Modification (CM) is derived. Coding professionals should verify code validity against the current fiscal year’s tabular list before submission, particularly for codes that have undergone reorganization in adjacent categories.

For practices navigating subsequent encounter coding conventions across multiple specialties, keeping up with annual ICD-10-CM updates is a recurring compliance responsibility. The October 1 effective date means codes used for encounters in September of one year may be invalid for the same type of encounter in October of the next. Track code validity by fiscal year, not calendar year.

Conclusion

Accurate assignment of S62.351P depends on three things: confirming the fracture is in the shaft of the second metacarpal of the left hand, confirming the encounter is a follow-up (not initial), and confirming radiographic evidence of malunion rather than nonunion or routine healing. The 7th character is the hinge point where most coding errors occur on these claims.

Pabau’s claims management software helps orthopedic and hand surgery practices build the documentation and coding workflow that prevents 7th character errors before they result in denials. To see how it works in practice, book a demo with the team.

Continue your research

Managing fracture follow-up documentation across multiple patients? Patient record management in Pabau links imaging results, clinical notes, and coding fields in a single encounter record.

Need structured intake for orthopedic and hand surgery follow-up visits? Digital forms in Pabau support standardized fracture follow-up templates that capture healing status, imaging references, and treatment plan elements.

Looking at how other injury codes are structured in ICD-10-CM? Injury-related ICD-10 coding walks through another complex injury code family with similar 7th character conventions.

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