Coronal Malalignment—When and How to Perform a Tibial Tubercle Osteotomy

Gardner, Elizabeth C.; Molho, David A.; Fulkerson, John P.

doi:10.1016/j.csm.2021.07.008

Cited by 11 publications

(7 citation statements)

References 34 publications

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“…This study supports the practice to combine bony alignment to soft tissue reconstruction [1, 28]. The MPFL reconstruction aims to stabilize the patella, not to force it into a tracking pattern inconsistent with is vector alignment [15, 16]…”

Section: Discussionsupporting

confidence: 72%

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Combined MPFL reconstruction and tibial tuberosity transfer avoid focal patella overload in the setting of elevated TT–TG distances

Berton

Salvatore

Nazarian

et al. 2022

Knee Surg Sports Traumatol Arthrosc

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PurposeObjectives are (1) to evaluate the biomechanical effect of isolated medial patellofemoral ligament (MPFL) reconstruction in the setting of increased tibial tuberosity–trochlear groove distance (TTTG), in terms of patella contact pressures, contact area and lateral displacement; (2) to describe the threshold of TTTG up to which MPFL reconstruction should be performed alone or in combination with tibial tuberosity transfer. MethodsA finite element model of the knee was developed and validated. The model was modified to simulate isolated MPFL reconstruction, tibial tuberosity transfer and MPFL reconstruction combined with tibial tuberosity transfer for patella malalignment. Two TT–TG distances (17 mm and 22 mm) were simulated. Patella contact pressure, contact area and lateral displacement were analysed. ResultsIsolated MPFL reconstruction, at early degrees of flexion, restored normal patella contact pressure when TTTG was 17 mm, but not when TTTG was 22 mm. After 60° of flexion, the TTTG distance was the main factor influencing contact pressure. Isolated MPFL reconstruction for both TTTG 17 mm and 22 mm showed higher contact area and lower lateral displacement than normal throughout knee flexion. Tibial tuberosity transfer, at early degrees of flexion, reduced the contact pressure, but did not restore the normal contact pressure. After 60° of flexion, the TTTG distance was the main factor influencing contact pressure. Tibial tuberosity transfer maintained lower contact area than normal throughout knee flexion. The lateral displacement was higher than normal between 0° and 30° of flexion (< 0.5 mm). MPFL reconstruction combined with tibial tuberosity transfer produced the same contact mechanics and kinematics of the normal condition. ConclusionThis study highlights the importance of considering to correct alignment in lateral tracking patella to avoid focal patella overload. Our results showed that isolated MPFL reconstruction corrects patella kinematics regardless of TTTG distance. However, isolated MPFL reconstruction would not restore normal patella contact pressure when TTTG is 22 mm. For TTTG 22 mm, the combined procedure of MPFL reconstruction and tibial tuberosity transfer provided an adequate patellofemoral contact mechanics and kinematics, restoring normal biomechanics. This data supports the use of MPFL reconstruction when the patient has normal alignment and the use of combined MPFL reconstruction and tibial tuberosity transfer in patients with elevated TT–TG distances to avoid focal overload.

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Section: Discussionsupporting

confidence: 72%

“…Despite its success, there are still no clear indications for isolated MPFL reconstruction, in particular for patients with increased tibial tuberosity–trochlear groove distance (TTTG) [16, 51]. Some studies reported good clinical outcomes, but many of those were underpowered [40].…”

Section: Introductionmentioning

confidence: 99%

Combined MPFL reconstruction and tibial tuberosity transfer avoid focal patella overload in the setting of elevated TT–TG distances

Berton

Salvatore

Nazarian

et al. 2022

Knee Surg Sports Traumatol Arthrosc

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“…Smith et al demonstrated through modelling pediatric patients with a history of patellar instability that for every degree of external tibial rotation through the knee, the TT-TG increases by 0.55 mm [18]. As surgical planning typically uses 20 mm as a TT-TG cutoff when considering a TTO, relatively small changes in tibiofemoral rotation could influence the decision to proceed with surgery [10,19]. Over a small period of 5 months on sequential imaging series, this study observed large changes in the TT-TG, from a 21.2% decrease to an increase of 61.1%, can occur.…”

Section: Discussionmentioning

confidence: 99%

“…This means that for more severe PFI, there is more external tibial rotation relative to the femur and, consequently, a larger TT-TG distance. With tibiofemoral rotation being a risk factor for elevated TT-TG, the addition of a TTO to surgical correction in PFI has traditionally been considered when the TT-TG distance is greater than 20 mm [10,11]. Further, a study by Hansen et al reported the need to standardise knee positioning during radiographic imaging as differences were found between supine and standing MRI scanning positions [12].…”

Section: Introductionmentioning

confidence: 99%

Measurement of TT‐TG can change with sequential MRIs due to variations in tibiofemoral rotation in patellofemoral instability patients

Pascual‐Leone,

Chipman,

Davie

et al. 2024

Knee surg. sports traumatol. arthrosc.

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PurposeThere are various anatomic risk factors for patellofemoral instability (PFI) that help guide surgical treatment, including the tibial tubercle to trochlear groove (TT‐TG) distance. However, no study has analysed the temporal changes in TT‐TG prior to surgical intervention. This study sought to understand the variations in TT‐TG over time for pediatric patients suffering from PFI prior to surgical intervention. The authors hypothesised that the TT‐TG would substantially change between time points.MethodsPatients undergoing medial patellofemoral ligament (MPFL) reconstruction between 2014 and 2019 by one of two fellowship‐trained orthopaedic surgeons were identified. Patients were included if they had two preoperative magnetic resonance imaging (MRI) performed on the same knee within 7.5 months of each other prior to any surgical intervention and had an initial TT‐TG greater than 10 mm.ResultsAfter considering 251 patients for inclusion, 21 patients met the final inclusion criteria. The mean age was 14.5 ± 2.5 years and 61.9% were female. TT‐TG was initially noted to be 15.1 ± 1.8 mm. At mean time after sequential MRIs of 5.0 ± 1.9 months, TT‐TG was noted to be 16.7 ± 3.2 mm. The differences between initial and subsequent TT‐TG ranged from a 21.2% decrease to a 61.1% increase, with a mean difference of an 11.3% increase. Comparison between initial and subsequent TT‐TG values demonstrated a significant difference (p = 0.017). Change in tibiofemoral rotation ranged from −9.2° to 7.5°. When comparing the change in TT‐TG to change in tibiofemoral rotation, a significant correlation was found (p = 0.019).ConclusionDespite only a mean time between MRIs of 5 months, variations in TT‐TG ranged from a decrease of 21.2% to an increase of 61.1%. The significant relationship between the changes in TT‐TG and changes in tibiofemoral rotation between MRIs suggest that TT‐TG measurements may vary due to variations in tibiofemoral rotation at the time of individual MRIs.Level of Evidence: Level IV.

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“… 7 TTO with distalization is the most common surgical treatment option for patella alta. 8 , 9 , 10 Despite evidence that suggests TTO with distalization leads to good radiographic, clinical, and functional outcomes, concerns about the risk of osseous complications with procedures involving complete detachment of the distal tuberosity remain, including fractures of the proximal tibia, loss of tibial tuberosity fixation, and delayed union or nonunion of the tuberosity. 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 We propose a distalizating TTO technique for the correction of patella alta that aims to minimize these complications through the creation of a V-shaped osteotomy, tubercle stabilization, and periosteum repair.…”

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confidence: 99%