Summary & Overview
CPT 77073: Lower Extremity Imaging for Leg-Length Measurement
CPT code 77073 denotes full-length lower extremity radiographic imaging from hips to ankles performed to measure leg-length discrepancy. This diagnostic procedure is clinically important for evaluating limb-length inequality that can contribute to gait abnormalities, back pain, and orthopedic planning for interventions such as epiphysiodesis or limb-lengthening procedures. Nationally, accurate measurement and consistent coding support care coordination between primary care, orthopedics, and rehabilitation services.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical intent and typical sites of service, plus what to expect in payer coverage frameworks and billing practice. The publication highlights billing and coding considerations for documentation of imaging from hips through ankles and provides benchmarks and policy context where available. It also outlines common clinical scenarios prompting measurement of leg-length discrepancy and intended use cases of the imaging study.
This material is written for clinicians, billing professionals, and policy analysts seeking a national perspective on the code’s clinical role, coding context, and payer landscape. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 77073 describes imaging of the lower extremities from the hips to the ankles to measure leg-length discrepancy. This service is a diagnostic imaging procedure intended to quantify differences in limb length and assess skeletal alignment.
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Service type: Diagnostic radiographic imaging for measurement of leg-length discrepancy
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Typical site of service: Hospital outpatient departments, freestanding imaging centers, or physician offices equipped for full-length lower extremity radiography
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Clinical & Coding Specifications
Clinical Context
A 14-year-old adolescent presents to an orthopedic imaging center with a history of leg-length discrepancy noted by the pediatrician and asymmetric gait. The clinical workflow begins with an orthopedic evaluation documenting limb-length concerns, physical examination including block testing, and an order for radiographic limb-length measurement from hips to ankles. The imaging technologist positions the patient supine or standing depending on protocol, includes calibration markers, and acquires full-length anteroposterior images of both lower extremities from the iliac crests/hip joints through the ankles. The radiologist reviews measurements, compares femoral and tibial segment lengths, documents side-to-side differences, and issues a formal report for the referring orthopedic surgeon. Results may inform management such as shoe lifts, physical therapy, epiphysiodesis planning, or preoperative templating for corrective procedures.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the physician interpretation separate from technical imaging. |
TC | Technical component | Use when billing only facility or equipment portion of the imaging service. |