synonyms: anteromedial tibial tubercle transfer, AMZ, Tibial Tubercle Transfer, fulkerson, tibial tubercle osteotomy (TTO).
Tibial Tubercle Transfer CPT
Tibial Tubercle Transfer Anatomy
Tibial Tubercle Transfer Indications
- Lateral patellar tilt / subluxation with Grade III or IV chondromalacia on the distal medial and/or lateral patellar facets.
- Patellofemoral arthritis.
- Failed lateral release.
- Tibial tubercle anteromedialization (Fulkerson osteotomy) is recommended for TT-TG (tibial tubercle (TT) to trochlear groove (TG) ) distances of more than 20 mm
Tibial Tubercle Transfer Contraindications
- Normal patellar articular cartilage: in this case there is no need to anteriorize the tibial turbercle and a straight medial transfer (Tillat) is inidcated.
- Absence of patellar malalignment
- Diffuse patellar Grade III/IV Chondromalacia
Tibial Tubercle Transfer Alternatives
Tibial Tubercle Transfer Planning / Special Considerations
- Councel patients on expected outcomes of improved symptoms, not completely normal knee.
- Moving tibial tubercle anteriorly shifts the more proximal patellar articular cartilage into contact earlier in the flexion arc. This unloads distal patellar articular lesions.
- Medialization decreases lateral and increases medial patellofemoral contact pressures
- Lateral and distal lesions with lateral patellar tracking (most common)= anteromedial tibial tubercle transfer via and oblique osteotomy. (Tibial Tubercle Transfer JP, Am J Sports Med 1990;18:490)
- Lateral lesion with lateral tracking = Trillat tibial tubercle transfer
- Distal lesion with normal proximal cartilage (uncommon) = anterioriation of tubercle
- consider concomitent autologous or allograft osteochondral core transfer especially if articular lesion is on trochlear side.
Tibial Tubercle Transfer Technique
- Sign operative site.
- Pre-operative antibiotics, +/- regional block.
- General endotracheal anesthesia
- Supine position. All bony prominences well padded.
- Examination under anesthesia.
- Tourniquet placed high on the thigh.
- Prep and drape in standard sterile fashion.
- Perform knee arthroscopy documenting condition of patellar cartilage and location of lesions. Patients should have near normal proximal medial facet cartilage for a successful anteromedial transfer. Perform chondroplasty as indicated.
- Exsanguinant leg the Eschmar bandage. Inflate tourniquet.
- Anterolateral longitudinal incision extending from the lateral patella to 5-6cm distal to the tibial tubercle.
- Expose patellar tendon and lateral retinaculum.
- Perform lateral release to the superior pole of the patella.
- Expose tibial tubercle both medially and laterally by subperiosteal sharp dissection. Expose the distal patellar tendon medial and laterally.
- Place custom anterior retractor on the proximal lateral tibia.
- Place Mitek Tracker guide and pin in place with slope determined based on pre-operative plan. Osteotomy should taper anteriorly distally.
- Begin osteotomy with multiple drill holes and saw.
- Complete osteotomy with osteotome. Two cuts are needed proximally ensure tibial tubercle remains intact
- Displace the tibial tubercle fragment anteromedially along the osteotomy plane. @15mm anteriorization.
- Secure tibial tuberlce with bone clamp and place knee through ROM ensure central tracting in the trochlear groove.
- Place two 4.5mm cortical lag screws for fixation. Proximal screw is placed 1-2cm distal to the patellar tendon insertion.
- Assess patellar tracking.
- Close in layers.
Tibial Tubercle Transfer Complications
- tibia fracture (avoid creating stress-riser in tibia with osteotomy cut)
- Compartment syndrome
- Skin slough
- Continued symptoms
- Painful hardware: generally screws are removed at 8-12 months post-op.
- Neurovascular injury
- Overcorrection . patellar instability
Tibial Tubercle Transfer Follow-up care
- Post-op: knee immobilizer or hinged brace locked in extention. Active and passive ROM exercises are start early 1-2 x per day. Toe-touch weight bearing.
- 7-10 Days: wound check, Continue knee immobilizer, daily ROM exercises. 25% Weight-bearing with crutches.
- 6 Weeks: Check xrays. wean out of immobilizer, Start active strengthening at 8 weeks. Gradually increase weight bearing to full-weight bearing provided xrays show evidence of union.
- 3 Months:
- 6 Months:
Tibial Tubercle Transfer Outcomes
Tibial Tubercle Transfer Review References
- Tibial Tubercle Transfer JP, in Masters Techniques in Orthopaedic Surgery: The Knee, 2nd ed.
- Sherman SL, Erickson BJ, Cvetanovich GL, Chalmers PN, Farr J 2nd, Bach BR Jr, Cole BJ. Tibial Tuberosity Osteotomy: Indications, Techniques, and Outcomes. Am J Sports Med. 2013 Nov 6;42(8):2006-2017
- Ramappa AJ, Apreleva M, Harrold FR, Fitzgibbons PG, Wilson DR, Gill TJ. The effects of medialization and anteromedialization of the tibial tubercle on patellofemoral mechanics and kinematics. Am J Sports Med. 2006 May;34(5):749-56. Epub 2006 Jan 25.