Patellar Tendon Tenodesis in Association With Tibial Tubercle Distalization for the Treatment of Episodic Patellar Dislocation With Patella Alta

Introduction. Patellar instability (PI) is a common finding in children. Current parameters describing patellofemoral joint alignment do not account for knee size. Additionally, most parameters utilize joint-crossing tibiofemoral landmarks and are prone to errors. The aim of the present study was to develop a knee size-independent parameter that is suitable for pediatric or small knees and determines the malpositioning of the distal patellar tendon insertion solely utilizing tibial landmarks. Methods. Sixty-one pediatric knees were included in the study. The tibial tubercle posterior cruciate ligament distance (TTPCL) was measured via magnetic resonance imaging (MRI). The tibial head diameter (THD) was utilized as a parameter for knee size. An index was calculated for the TTPCL and THD (TTPCL/THD). One-hundred adult knees were analyzed to correlate the data with a normalized cohort. Results. The THD was significantly lower in healthy females than in males (69.3 mm ± 0.8 mm vs. 79.1 mm ± 0.7 mm; p<0.001) and therefore was chosen to serve as a knee size parameter. However, no gender differences were found for the TTPCL/THD index in the healthy adult study cohort. The TTPCL/THD was significantly higher in adult PI patients than in the control group (0.301 ± 0.007 vs. 0.270 ± 0.007; p=0.005). This finding was repeated in the PI group when the pediatric cohort was analyzed (0.316 ± 0.008 vs. 0.288 ± 0.010; p=0.033). Conclusion. The TTPCL/THD index represents a novel knee size-independent measure describing malpositioning of the distal patellar tendon insertion determined solely by tibial landmarks.

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Treatment of patella alta in patients with episodic patellar dislocation: a systematic review

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-013-2445-8 ◽

2013 ◽

Vol 22 (10) ◽

pp. 2545-2550 ◽

Cited By ~ 40

Author(s):

Robert A. Magnussen ◽

Vito De Simone ◽

Sebastien Lustig ◽

Philippe Neyret ◽

David C. Flanigan

Keyword(s):

Systematic Review ◽

Patellar Dislocation ◽

Patella Alta

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Tibial-tubercle avulsion and patellar-tendon rupture in pre-pubertal child with osteogenesis imperfecta(OI): Case report and review of current treatment in OI

Journal of Clinical Orthopaedics and Trauma ◽

10.1016/j.jcot.2020.01.013 ◽

2020 ◽

Vol 11 (2) ◽

pp. 339-343

Author(s):

Rujuta Mehta ◽

Uday Mahajan

Keyword(s):

Case Report ◽

Osteogenesis Imperfecta ◽

Patellar Tendon ◽

Tendon Rupture ◽

Current Treatment ◽

Tibial Tubercle ◽

Patellar Tendon Rupture

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Tibial Tubercle–Roman Arch Distance: A New Measurement of Patellar Dislocation and Indication of Tibial Tubercle Osteotomy

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120914872 ◽

2020 ◽

Vol 8 (4) ◽

pp. 232596712091487 ◽

Cited By ~ 1

Author(s):

Zijie Xu ◽

Hua Zhang ◽

Binjie Fu ◽

Sheikh Ibrahimrashid Mohamed ◽

Jian Zhang ◽

...

Keyword(s):

Relative Position ◽

Patellar Dislocation ◽

Trochlear Dysplasia ◽

Tibial Tubercle ◽

Trochlear Groove ◽

Tibial Tubercle Osteotomy ◽

Distance Measurements ◽

Significant Difference ◽

Reliable Parameter ◽

And Control

Background: The surgical indication for tibial tubercle osteotomy (TTO) has been based on a tibial tubercle–trochlear groove (TT-TG) distance of 20 mm or greater in patients with patellar dislocation. However, the measurement of this parameter is less reliable in patients with trochlear dysplasia. Hypothesis: The novel measurement of tibial tubercle–Roman arch (TT-RA) distance would be a reliable parameter for identifying the relative position of the tibial tubercle in patients with patellar dislocation, especially those with trochlear dysplasia. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 56 patients with a diagnosis of patellar dislocation and 60 volunteers (60 knee joints) without a history of lower extremity pain or injury were included in our study. The TT-RA distance, TT-TG distance, and some femoral anatomic parameters were assessed by use of computed tomography. The measurements were performed by a radiologist and an orthopaedic surgeon in a blinded and randomized fashion. The difference in each parameter between the study and control groups was analyzed through use of an unpaired t test. Receiver operating characteristic curve analysis was performed to evaluate the discriminatory capacity of the included parameters. The cutoff values of the included measurements with specificity and sensitivity were calculated. In addition, the TT-TG distance and TT-RA distance were analyzed using the Dejour classification to evaluate the intraclass correlation coefficient (ICC) of each parameter in different types of femoral trochlea. Result: A significant difference for TT-RA distance was found between the study group (23.24 ± 4.41 mm) and control group (19.15 ± 4.24 mm) ( P < .001). The TT-RA distance had an area under the curve of 0.757. At a value greater than 23.74 mm, TT-RA distance had 53.57% sensitivity and 88.33% specificity for patellar dislocation. The ICCs of TT-RA distance measurements were excellent in all Dejour classifications (>0.939), whereas the ICCs of TT-TG distance measurements were relatively lower than the ICCs of TT-RA distance measurements. According to the data from included healthy individuals, the pathological TT-RA distance threshold was 26 mm. Conclusion: Compared with TT-TG distance, the TT-RA distance is a more reliable parameter for identifying the relative position of the tibial tubercle in patients with trochlear dysplasia. For patients with a TT-RA distance greater than 26 mm, surgery should be considered to correct the malposition of the tibial tubercle.

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Evaluation of Intrinsic Biomechanical Risk Factors in Patellar Tendinopathy: A Retrospective Radiographic Case-Control Series

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967118816038 ◽

2018 ◽

Vol 6 (12) ◽

pp. 232596711881603 ◽

Cited By ~ 6

Author(s):

Michael J. Dan ◽

James McMahon ◽

William C.H. Parr ◽

David Broe ◽

Phil Lucas ◽

...

Keyword(s):

Risk Factors ◽

Patellar Tendon ◽

Patella Alta ◽

Patellar Tendinopathy ◽

Moment Arm ◽

Control Series ◽

Pivot Point ◽

Lever Arm ◽

Radiographic Measurements ◽

Significant Difference

Background: Patellar tendinopathy is an overuse condition often affecting athletes. It has been postulated that patellar tendinopathy is associated with patella alta; however, this and any other anatomic risk factors have not been identified. Purpose: To explore whether lever arm differences from radiographic measurements exist between patients with and without tendinopathy. This may provide surgeons with a simple radiographic means to identify patients at risk. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Magnetic resonance imaging scans of the knee from a sports imaging facility were screened and reviewed to identify 2 groups of patients: those with and those without imaging signs of patellar tendinopathy. The lateral radiographs were reviewed and measurements made to determine (1) lever arm ratio, (2) moment arm ratio, (3) angle between the moment and line of pull of the patellar tendon, (4) patellar tendon pivot point angle, and (5) patellar height (alta). Measurements were obtained directly from radiographs. The images and measurements were reviewed by 2 experienced orthopaedic clinicians. Results: A total of 105 patients were included in this study: 52 with patellar tendinopathy and 53 without patellar tendinopathy (controls). The mean age was similar between groups (23 years); females accounted for 8 of 52 patients with patellar tendinopathy and 24 of 53 patients without. The lever arm ratio in the group with patellar tendinopathy versus controls was 1.71 versus 1.01 ( P = .01), with a moment arm difference of 1.00 versus 0.80 ( P < .01), respectively. There was no difference detected between groups for patellar tendon angle, patellar tendon pivot point angle, knee flexion angle, or incidence of patella alta. No correlation was found with our measurements and the Insall-Salvati ratio. Statistical analysis was also performed according to sex, and a statistically significant difference between groups was found for differences in lever arm ratio and moment arm. Conclusion: The lever arm ratio and moment arm ratio from lateral radiographs were significantly different between patients with and without patellar tendinopathy. Further study is needed on the biomechanical implications of the pivot point and how altering it can affect stress within the patellar tendon, patellofemoral joint, and associated clinical outcomes.

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