Patella alta and patella infera. Their etiological role in patellar dislocation, chondromalacia, and apophysitis of the tibial tubercle

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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Anisometry of Medial Patellofemoral Ligament Reconstruction in the Setting of Patella Alta and Increased Tibial Tubercle-Trochlear Groove (TT-TG) Distance

Arthroscopy The Journal of Arthroscopic and Related Surgery ◽

10.1016/j.arthro.2016.03.054 ◽

2016 ◽

Vol 32 (6) ◽

pp. e10 ◽

Cited By ~ 3

Author(s):

Lauren Redler ◽

Kathleen Meyers ◽

Jacqueline Munch ◽

Elizabeth Dennis ◽

Joseph Nguyen ◽

...

Keyword(s):

Ligament Reconstruction ◽

Medial Patellofemoral Ligament ◽

Patella Alta ◽

Tibial Tubercle ◽

Trochlear Groove ◽

Medial Patellofemoral Ligament Reconstruction

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Risk Factors and Time to Recurrent Ipsilateral and Contralateral Patellar Dislocations

The American Journal of Sports Medicine ◽

10.1177/0363546517704178 ◽

2017 ◽

Vol 45 (9) ◽

pp. 2105-2110 ◽

Cited By ~ 56

Author(s):

Tyson C. Christensen ◽

Thomas L. Sanders ◽

Ayoosh Pareek ◽

Rohith Mohan ◽

Diane L. Dahm ◽

...

Keyword(s):

Risk Factors ◽

Cumulative Incidence ◽

Patellar Dislocation ◽

Patellar Instability ◽

Trochlear Dysplasia ◽

Patella Alta ◽

Time To Recurrence ◽

Lateral Patellar Dislocation ◽

Ipsilateral Recurrence ◽

First Time

Background: Previous studies have reported variable rates of recurrent lateral patellar instability mainly because of limited cohort sizes. In addition, there is currently a lack of information on contralateral patellar instability. Purpose: To evaluate the rate of recurrent ipsilateral patellar dislocations and contralateral patellar dislocations after a first-time lateral patellar dislocation. Additionally, risk factors associated with recurrent dislocations (ipsilateral or contralateral) and time to recurrence were investigated. Study Design: Cohort study; Level of evidence, 3. Methods: This population-based study included 584 patients with a first-time lateral patellar dislocation occurring between 1990 and 2010. A retrospective review was conducted to gather information about the injury, subsequent dislocations (ipsilateral or contralateral), and structural characteristics including trochlear dysplasia, patella alta, and tibial tubercle to trochlear groove (TT-TG) distance. Risk factors were assessed to delineate associations with subsequent dislocations and time to recurrence. Results: At a mean follow-up of 12.4 years, 173 patients had ipsilateral recurrence, and 25 patients had a subsequent contralateral dislocation. At 20 years, the cumulative incidence of ipsilateral recurrence was 36.0%, while the cumulative incidence of contralateral dislocations was 5.4%. Trochlear dysplasia (odds ratio [OR], 18.1), patella alta (OR, 10.4), age <18 years at the time of the first dislocation (OR, 2.4), elevated TT-TG distance (OR, 2.1), and female sex (OR, 1.5) were associated with recurrent ipsilateral dislocations. Time to recurrence was significantly decreased in patients with trochlear dysplasia (23.0 months earlier time to recurrence; P < .001), elevated TT-TG distance (18.5 months; P < .001), patella alta (16.4 months; P = .001), and age <18 years at the time of the first dislocation (15.4 months; P < .001). Risk factors for subsequent contralateral dislocations included patella alta and trochlear dysplasia. Conclusion: At 20 years after a first-time lateral patellar dislocation, the cumulative incidence of recurrent ipsilateral patellar dislocations was 36.0%, compared with 5.4% for contralateral dislocations. Trochlear dysplasia, elevated TT-TG distance, patella alta, age <18 years at the time of the first dislocation, and female sex were associated with ipsilateral recurrence. Trochlear dysplasia, elevated TT-TG distance, patella alta, and age <18 years at the time of the first dislocation were predictive of a statistically significant decrease in time to recurrence.

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(TT-TG)/TW is The Optimal Indicator for Diagnosing a Lateralized 2 Tibial Tubercle in Recurrent Patellar Dislocation Requiring Surgical 3 Stabilization

Arthroscopy The Journal of Arthroscopic and Related Surgery ◽

10.1016/j.arthro.2021.11.030 ◽

2021 ◽

Author(s):

Peng Su ◽

Hangjia Hu ◽

Shu Li ◽

Tianhao Xu ◽

Jian Li ◽

...

Keyword(s):

Patellar Dislocation ◽

Tibial Tubercle ◽

Recurrent Patellar Dislocation

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Peer review report 3 on “Arthroscopic lateral retinacular release, medial retinacular plication and partial medial tibial tubercle transfer for recurrent patellar dislocation”

International Journal of Surgery ◽

10.1016/j.ijsu.2017.07.017 ◽

2017 ◽

Vol 37 ◽

pp. 406

Keyword(s):

Peer Review ◽

Patellar Dislocation ◽

Tibial Tubercle ◽

Lateral Retinacular Release ◽

Recurrent Patellar Dislocation ◽

Tibial Tubercle Transfer

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Increased tibial tubercle-trochlear groove and patellar height indicate a higher risk of recurrent patellar dislocation following medial reefing

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-021-06581-0 ◽

2021 ◽

Author(s):

Marc-Daniel Ahrend ◽

Tobias Eisenmann ◽

Moritz Herbst ◽

Boyko Gueorguiev ◽

Gabriel Keller ◽

...

Keyword(s):

Patellar Dislocation ◽

Recurrent Dislocation ◽

Patellar Height ◽

Tibial Tubercle ◽

Trochlear Groove ◽

Recurrent Patellar Dislocation ◽

Patellar Tilt ◽

Level Of Evidence ◽

Sulcus Angle ◽

Patellar Shift

Abstract Purpose Identifying anatomical risk factors on recurrent dislocation after medial reefing is important for deciding surgical treatment. The present study aimed to retrospectively analyze the preoperative magnetic resonance imaging (MRI)-based parameters of patients treated with medial reefing and whether these parameters lead to a higher risk of recurrent dislocation. Methods Fifty-five patients (18.6 ± 6.6 years) who underwent medial reefing after primary traumatic patellar dislocation (84% with medial patellofemoral ligament [MPFL] rupture) were included. Patients were followed up for at least 24 months postoperatively (3.8 ± 1.2 years) to assess the incidence of recurrent patellar dislocation. In patients without recurrent dislocation, the Kujala and subjective IKDC scores were assessed. Moreover, the tibial tubercle-trochlear groove (TT-TG), sulcus angle, patellar tilt, patellar shift, and lateral trochlea index (LTI) were measured. The patellar height was measured using the Caton-Dechamps (CDI), Blackburne-Peel (BPI), and Insall-Salvati index (ISI). The cohort was subclassified into two groups with and without recurrent dislocation. Differences between groups were analyzed with respect to the MRI parameters. Results Forty percent had a pathological sulcus angle of > 145°, 7.2% had an LTI of < 11°, 47.3% had a patellar tilt of > 20°, and 36.4% had a TT-TG of ≥ 16 mm. Increased patellar height was observed in 34.5, 65.5, and 34.5% of the patients as per CDI, BPI, and ISI, respectively. Nineteen (34.5%) patients suffered from recurrent dislocation. Compared with patients without recurrent dislocation, those with recurrent dislocation had a significantly lower LTI (p = 0.0467). All other parameters were not significantly different between the groups. Risk factor analysis showed higher odds ratios (OR > 2), although not statistically significant, for MPFL rupture (OR 2.05 [95% confidence interval 0.38–11.03], LTI (6.6 [0.6–68.1]), TT-TG (2.9 [0.9–9.2]), and patellar height according to ISI (2.3 [0.7–7.5]) and CDI (2.3 [0.7–7.5])). Patients without recurrent dislocation had a Kujala score of 93.7 ± 12.1 (42–100) points and an IKDC score of 90.6 ± 11.7 (55.2–100) points. Conclusion Anatomical, MRI-based parameters should be considered before indicating medial reefing. A ruptured MPFL, an LTI < 11°, a TT-TG ≥ 16 mm, a patellar tilt > 20 mm, and an increased patellar height according to ISI and CDI were found to be associated, although not significantly, with a higher risk (OR > 2) of recurrent patellar dislocation after medial reefing. Thorough preoperative analysis is crucial to reduce the risk of recurrent dislocation in young patient cohorts. Level of evidence Level IV

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