Tibial tuberosity transfer

 

Patellar maltracking - what are the surgical options?

The patella is at the mercy of the chain of structures that holds it in position in the groove of the femur. It may experience extreme forces if the anatomy is abnormal, and the joint cartilage may become damaged, the patella painful, and subluxations and dislocations may occur.

When the patient is being investigated, the surgeon needs to evaluate:

• whether or not the patella and/or its underlying groove are anatomically normal (patellar dysplasia and trochlear dysplasia)
• whether the 'stays' at the side of the patella are pulling it too much to one side (tight lateral retinaculum, patellar tilt and excessive lateral pressure syndrome)
• whether the patella is being abnormally tugged over to the side by the patella tendon being attached in a poor position (poor tibial tuberosity alignment)

In this paper we are talking about the third possibility, where poor tibial tuberosity alignment tugs on the patella during its tracking. Several procedurs have been developed to move the tibial tuberosity, together with the patellar tendon, into a better mechanical position

Because in these procedures the corrective surgery is performed distal to the patella (below it) the various surgeries of tibial tuberosity transfer are lumped under the name of distal realignment procedures.

 

 

• Quote from a peer-reviewed paper:

  "Patellar instability can be caused by a multitude of factors, including MPFL injury, trochlear dysplasia, patella alta, and lateralization of the force vector. Each factor should be considered to have a variable contribution, and should be assessed as a potential contribution prior to considering surgery."

  Citation: Krishnan H, Eldridge JD, Clark D, Metcalfe AJ, Stevens JM, Mandalia V. Tibial tuberosity-trochlear groove distance: does it measure up? Bone Jt Open. 2022 Mar;3(3):268-274. doi: 10.1302/2633-1462.33.BJO-2021-0107. PMID: 35321559; PMCID: PMC8965791.

 

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Distal realignment procedures

Several distal realignment procedures have been developed to move the tibial tuberosity into a better position,

Although the concept seems simple, the number of procedures that have been developed reflect the difficulty in acheiving a good outcome -

 

• Quote from peer-reviewed paper:

  "Although excellent outcomes can be achieved, this procedure is not without complications..." "The Maquet technique...has largely been abandoned...for skin necrosis, compartment syndrome, and nonunion." "Nonunion is a recognized risk after tibial tubercle transfer" as well as "fracture of the proximal tibia...increased when the tibial tubercle is completely detached from its hinge."

  Citation: Grimm NL, Lazarides AL, Amendola A. Tibial Tubercle Osteotomies: a Review of a Treatment for Recurrent Patellar Instability. Curr Rev Musculoskelet Med. 2018 Jun;11(2):266-271. doi: 10.1007/s12178-018-9482-3. PMID: 29721692; PMCID: PMC5970117.

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How does the TT-TG distance contribute to decision-making?

The surgeon is able to assess how much the tibial tuberosity needs to be moved by measuring the TT-TG distance. This is a measurement derived from a CT scan or MRI scan, where overlapping views of the groove and the tuberosity give an estimate of how far out of alignment the tuberosity is. If it is more than 15-20mm it is considered significant.

 

 

• Quote from peer-reviewed paper:

  "TT-TG is one guide to help determine the need for a medializing TTO, although its interpretation is complex and the high rates of subsequent patellofemoral OA in patients treated this way imply that it should be used with caution."

  Citation: Krishnan H, Eldridge JD, Clark D, Metcalfe AJ, Stevens JM, Mandalia V. Tibial tuberosity-trochlear groove distance: does it measure up? Bone Jt Open. 2022 Mar;3(3):268-274. doi: 10.1302/2633-1462.33.BJO-2021-0107. PMID: 35321559; PMCID: PMC8965791.

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Forum discussions

• Fulkerson

  Post-op experiences after Fulkerson osteotomy

• Considering surgery to lengthen patella tendon

  A long conversation including many aspects of tibial tubercle osteotomy.

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