Coding Ahead
CasePilot
Medical Coding Assistant
Case2Code
Search and Code Lookup Tool
RedactPHI
HIPAA-Compliant PHI Redaction
DetectICD10CM
ICD-10-CM Code Detection
Log in Register free account
1 code page views remaining. Guest accounts are limited to 1 page view. Register free account to get 5 more views.
Log in Register free account

Official Description

Reconstruction of dislocating patella; (eg, Hauser type procedure)

© Copyright 2025 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 27420 refers to the surgical procedure known as the reconstruction of a dislocating patella, commonly performed to address issues related to patellar instability. This procedure is particularly relevant for patients who experience recurrent dislocations of the patella, which can lead to pain, functional impairment, and decreased quality of life. The reconstruction aims to restore proper alignment and stability of the patella within the knee joint. The Hauser type procedure, a specific technique used in this surgery, involves a distal transfer of the tibial tuberosity, which is a bony prominence on the tibia where the patellar tendon attaches. By repositioning the tibial tuberosity, the surgeon can improve the tracking of the patella during knee movement, thereby reducing the likelihood of future dislocations. The procedure is performed through a lateral incision, allowing access to the necessary anatomical structures while minimizing damage to surrounding tissues. Overall, CPT® Code 27420 encapsulates a critical intervention for managing patellar dislocation and enhancing knee function.

© Copyright 2025 Coding Ahead. All rights reserved.

1. Indications

The procedure associated with CPT® Code 27420 is indicated for patients experiencing recurrent dislocations of the patella. This condition may present with the following symptoms or conditions:

  • Recurrent Patellar Dislocation: Patients who have a history of the patella dislocating multiple times, leading to instability and pain.
  • Patellar Instability: Individuals who exhibit signs of the patella not tracking properly within the femoral groove during knee movement.
  • Knee Pain: Patients may report pain localized around the knee, particularly during activities that involve bending or straightening the leg.
  • Functional Impairment: Difficulty in performing daily activities or sports due to the instability of the patella.

2. Procedure

The procedure for CPT® Code 27420 involves several critical steps to effectively reconstruct the dislocating patella:

  • Step 1: The surgeon begins by making an incision lateral to the patella, extending across the tibial tuberosity and continuing distally along the anterior ridge of the tibia. This incision provides access to the underlying structures necessary for the procedure.
  • Step 2: Once the incision is made, the surgeon elevates the muscles overlying the anterior compartment of the leg to expose the patellar tendon and tibial tuberosity. This step is crucial for visualizing the anatomical landmarks involved in the reconstruction.
  • Step 3: The medial and lateral borders of the patellar tendon and tibial tuberosity are carefully exposed. This exposure allows the surgeon to assess the alignment and condition of these structures before proceeding with the reconstruction.
  • Step 4: An incision is made through the periosteum, which is the connective tissue surrounding the bone, distal to the tibial tuberosity. This incision is necessary to access the bone for the subsequent osteotomy.
  • Step 5: The surgeon performs an osteotomy to free the tibial tuberosity distally, medially, and laterally. This step involves cutting the bone to allow for the repositioning of the tuberosity.
  • Step 6: A portion of the tibial tuberosity is removed at its distal end, which is essential for achieving the desired alignment of the patella. The remaining portion of the tuberosity is then temporarily secured to the underlying bony bed.
  • Step 7: The patella is aligned within the intercondylar groove of the femur, ensuring that it tracks properly during knee movement. This alignment is critical for the success of the procedure.
  • Step 8: The surgeon assesses patellar tracking to determine if there is any under- or overcorrection. This assessment is vital to ensure that the patella will function correctly post-surgery.
  • Step 9: Once proper alignment is confirmed, one or more screws are placed to secure the tibial tuberosity in its new position, stabilizing the reconstruction and allowing for healing.

3. Post-Procedure

After the completion of the reconstruction procedure, patients typically require a period of post-operative care to ensure proper healing and recovery. This may include immobilization of the knee in a brace or splint to prevent movement that could jeopardize the surgical repair. Physical therapy is often initiated to restore range of motion, strength, and function to the knee joint. Patients are monitored for any signs of complications, such as infection or improper healing. The expected recovery time can vary based on individual factors, but adherence to rehabilitation protocols is essential for achieving optimal outcomes and preventing future dislocations.

Short Descr REVISION OF UNSTABLE KNEECAP
Medium Descr RCNSTJ DISLOCATING PATELLA
Long Descr Reconstruction of dislocating patella; (eg, Hauser type procedure)
Status Code Active Code
Global Days 090 - Major Surgery
PC/TC Indicator (26, TC) 0 - Physician Service Code
Multiple Procedures (51) 2 - Standard payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 1 - 150% payment adjustment for bilateral procedures applies.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 2 - Payment restriction for assistants at surgery does not apply to this procedure...
Co-Surgeons (62) 1 - Co-surgeons could be paid, though supporting documentation is required...
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Hospital Part B services paid through a comprehensive APC
ASC Payment Indicator Surgical procedure on ASC list in CY 2007; payment based on OPPS relative payment weight.
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P3D - Major procedure, orthopedic - other
MUE 1
CCS Clinical Classification 152 - Arthroplasty knee
22 Increased procedural services: when the work required to provide a service is substantially greater than typically required, it may be identified by adding modifier 22 to the usual procedure code. documentation must support the substantial additional work and the reason for the additional work (ie, increased intensity, time, technical difficulty of procedure, severity of patient's condition, physical and mental effort required). note: this modifier should not be appended to an e/m service.
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
58 Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
78 Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period: it may be necessary to indicate that another procedure was performed during the postoperative period of the initial procedure (unplanned procedure following initial procedure). when this procedure is related to the first, and requires the use of an operating/procedure room, it may be reported by adding modifier 78 to the related procedure. (for repeat procedures, see modifier 76.)
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
AS Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery
CR Catastrophe/disaster related
GC This service has been performed in part by a resident under the direction of a teaching physician
LT Left side (used to identify procedures performed on the left side of the body)
RT Right side (used to identify procedures performed on the right side of the body)
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
Date
Action
Notes
Pre-1990 Added Code added.
Code
Description
Code
Description
Code
Description
Code
Description
Code
Description
CasePilot

Get instant expert-level medical coding assistance.

Ask about:
CPT Codes Guidelines Modifiers Crosswalks NCCI Edits Compliance Medicare Coverage
Example: "What is CPT code 99213?" or "Guidelines for E/M services"