Influence of tibial tuberosity position and trochlear depth on patellar tracking in patellar instability: Variations with Patella Alta

Purpose The aim of the study was to test the distalization and medialization of the tibial tuberosity (DMTT) for the treatment of patellar instability associated with patella alta, focusing on residual instability and pain. Methods Twenty-four consecutive patients (26 knees) suffering from patellofemoral instability and patella alta were treated by DMTT. Two groups were identified, which differed for documented history of frank patella dislocation. The groups were named objective patellar instability (OPI) (history of dislocation) and potential patella instability (PPI) (no dislocation). Outcome was measured with visual analogue scale (VAS), Kujala score, and Tegner score. Comparison between groups was performed using Student's t-test, Wilcoxon rank score, and Fisher's exact test (significance at p < 0.05). Results At 50 ± 18 and 41 ± 18 months of follow-up, respectively, both PPI and OPI groups obtained a significant pain reduction and functional improvement. The PPI group showed a significant decrease of the subjective instability. No procedure-related complications were reported. Conclusion This study suggests that DMTT is a viable option for PPI patients with patella alta. The outcome was comparable between PPI and OPI cases; however, decrease in subjective instability was significantly greater in PPI patients. Level of Evidence Level III, retrospective comparative study.

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Factors Influencing Graft Function following MPFL Reconstruction: A Dynamic Simulation Study

The Journal of Knee Surgery ◽

10.1055/s-0040-1702185 ◽

2020 ◽

Author(s):

Miho J. Tanaka ◽

Andrew J. Cosgarea ◽

Jared M. Forman ◽

John J. Elias

Keyword(s):

Dynamic Simulation ◽

Knee Flexion ◽

Patellar Instability ◽

Graft Function ◽

Lateral Position ◽

Tibial Tuberosity ◽

Mpfl Reconstruction ◽

Patellar Tracking ◽

Graft Tension ◽

Patellar Maltracking

AbstractMedial patellofemoral ligament (MPFL) reconstruction is currently the primary surgical procedure for treating recurrent lateral patellar instability. The understanding of graft function has largely been based on studies performed with normal knees. The current study was performed to characterize graft function following MPFL reconstruction, focusing on the influence of pathologic anatomy on graft tension, variations with knee flexion, and the influence on patellar tracking. Knee squatting was simulated with 15 multibody dynamic simulation models representing knees being treated for recurrent lateral patellar instability. Squatting was simulated in a preoperative condition and following MPFL reconstruction with a hamstrings tendon graft set to allow 0.5 quadrants of lateral patellar translation with the knee at 30 degrees of flexion. Linear regressions were performed to relate maximum tension in the graft to parameters of knee anatomy. Repeated measures comparisons evaluated variations in patellar tracking at 5-degree increments of knee flexion. Maximum graft tension was significantly correlated with a parameter characterizing lateral position of the tibial tuberosity (maximum lateral tibial tuberosity to posterior cruciate ligament attachment distance, r 2 = 0.73, p < 0.001). No significant correlations were identified for parameters related to trochlear dysplasia (lateral trochlear inclination) or patella alta (Caton–Deschamps index and patellotrochlear index). Graft tension peaked at low flexion angles and was minimal by 30 degrees of flexion. MPFL reconstruction decreased lateral patellar shift (bisect offset index) compared with preoperative tracking at all flexion angles from 0 to 50 degrees of flexion, except 45 degrees. At 0 degrees, the average bisect offset index decreased from 0.81 for the preoperative condition to 0.71. The results indicate that tension within an MPFL graft increases with the lateral position of the tibial tuberosity. The graft tension peaks at low flexion angles and decreases lateral patellar maltracking. The factors that influence graft function following MPFL reconstruction need to be understood to limit patellar maltracking without overloading the graft or over constraining the patella.

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Three-dimensional transfer of tibial tuberosity for patellar instability with patella alta preserves patellar position and clinical outcomes: A minimum 3-year follow-up study

Journal of Orthopaedic Science ◽

10.1016/j.jos.2021.06.003 ◽

2021 ◽

Author(s):

Shuhei Otsuki ◽

Kuniaki Ikeda ◽

Nobuhiro Okuno ◽

Yoshinori Okamoto ◽

Hitoshi Wakama ◽

...

Keyword(s):

Clinical Outcomes ◽

Patellar Instability ◽

Three Dimensional ◽

Tibial Tuberosity ◽

Patella Alta ◽

Follow Up Study ◽

Patellar Position

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Geometry of Torsional Malalignment Syndrom: Trochlear Dysplasia but not Torsion Predicts Lateral Patellar Instability

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00222 ◽

2019 ◽

Vol 7 (6_suppl4) ◽

pp. 2325967119S0022

Author(s):

Peter Balcarek ◽

Dennis Vogel

Keyword(s):

Inclination Angle ◽

Patellar Instability ◽

Trochlear Dysplasia ◽

Patellofemoral Pain ◽

Tibial Tuberosity ◽

Patellar Tracking ◽

Trochlear Groove ◽

Type B ◽

Tibial Torsion ◽

Torsional Malalignment

Aims and Objectives: To analyze parameters of limb malalignment and patellar tracking in patients with torsional malalignment syndrome presenting with clinical symptoms of either patellofemoral pain or patellar instability. Materials and Methods: Between April 2015 and July 2017, 428 patients were treated for lateral patellar instability (LPD), and 333 patients were treated for patellofemoral pain syndrome (PFPS). Sixty-two patients (14.5%) with patellar instability (LPD group) and 29 patients (8.7%) with patellofemoral pain (PFPS group) had additional torsional malalignment and were included in this study. All patients underwent magnetic resonance imaging assessment of torsional alignment and patellar tracking, including femoral antetorsion, tibial torsion, knee rotation, tibial tuberosity-trochlear groove distance, tibial tuberosity-posterior cruciate ligament distance, Dejour’s classification of trochlear dysplasia, lateral trochlear inclination angle, and patellar height Results: Groups differed significantly in terms of trochlear dysplasia (p<0.001), lateral trochlear inclination angle (p<0.001) and tibial tuberosity-trochlear groove distance (p=0.0167) but did not differ in terms of femoral torsion (LPD group 20.02° +/- 8.8°; PFPS group 20.03° +/- 7.91°; p=0.8545), tibial torsion (LPD group 39.53° +/- 9.23°; PFPS group 41.24° +/- 7.28°; p=0.3616), and knee rotation (LPD group 10.42° +/- 5.16°; PFPS group 8.48° +/- 7.81°; p=0.0163). Only measures of coronal alignment were positively correlated. This was also true for the tibial tuberosity-trochlear groove distance and knee rotation but not for any other parameters of torsional limb alignment. Trochlear dysplasia (type B-D) was identified as the only significant predictor of patellar instability. Conclusion: Torsional malalignment syndrome, represented in this study by two clinical entities - PFPS and LPD - is not characterized by a typical constellation of different malalignment parameters. Between groups, parameters differed significantly only in terms of trochlear dysplasia and the tibial tuberosity-trochlear groove distance, with trochlear dysplasia (type B-D), but not torsion, identified as predictor of lateral patellar instability.

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Patellofemoral reconstruction for patellar instability with patella alta in middle-aged patients: Clinical outcomes

Orthopaedics & Traumatology Surgery & Research ◽

10.1016/j.otsr.2018.01.003 ◽

2018 ◽

Vol 104 (2) ◽

pp. 217-221 ◽

Cited By ~ 2

Author(s):

S. Otsuki ◽

Y. Okamoto ◽

T. Murakami ◽

K. Nakagawa ◽

N. Okuno ◽

...

Keyword(s):

Clinical Outcomes ◽

Patellar Instability ◽

Patella Alta ◽

Middle Aged ◽

Aged Patients

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Clinical Comparison of Medial Patellofemoral Ligament Reconstruction With or Without Tibial Tuberosity Transfer for Recurrent Patellar Instability

The American Journal of Sports Medicine ◽

10.1177/03635465211037716 ◽

2021 ◽

pp. 036354652110377

Author(s):

Jong-Min Kim ◽

Jae-Ang Sim ◽

HongYeol Yang ◽

Young-Mo Kim ◽

Joon-Ho Wang ◽

...

Keyword(s):

Clinical Outcomes ◽

Patellar Instability ◽

Medial Patellofemoral Ligament ◽

Tibial Tuberosity ◽

Mpfl Reconstruction ◽

Trochlear Groove ◽

Functional Failure ◽

Radiological Parameters ◽

Recurrent Patellar Instability

Background: No clear guidelines or widespread consensus has defined a threshold value of tibial tuberosity–trochlear groove (TT-TG) distance for choosing the appropriate surgical procedures when additional tibial tuberosity osteotomy (TTO) should be added to augment medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability. Purpose: To compare the clinical outcomes between MPFL reconstruction and MPFL reconstruction with TTO for patients who have patellar instability with a TT-TG distance of 15 to 25 mm. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively analyzed 81 patients who underwent surgical treatment using either MPFL reconstruction or MPFL reconstruction with TTO for recurrent patellar instability with a TT-TG distance of 15 to 25 mm; the mean follow-up was 25.2 months (range, 12.0-53.0 months). The patients were divided into 2 groups: isolated MPFL reconstruction (iMPFL group; n = 36) performed by 2 surgeons and MPFL reconstruction with TTO (TTO group; n = 45) performed by another 2 surgeons. Clinical outcomes were assessed using the Kujala score, Knee injury and Osteoarthritis Outcome Score, and Tegner activity score. Radiological parameters, including patellar height, TT-TG distance, patellar tilt, and congruence angle were compared between the 2 groups. Functional failure based on clinical apprehension sign, repeat subluxation or dislocation, and subjective instability and complications was assessed at the final follow-up. We also compared clinical outcomes based on subgroups of preoperative TT-TG distance (15 mm ≤ TT-TG ≤ 20 mm vs 20 mm < TT-TG ≤ 25 mm). Results: All of the clinical outcome parameters significantly improved in both groups at the final follow-up ( P < .001), with no significant differences between groups. The radiological parameters also showed no significant differences between the 2 groups. The incidence of functional failure was similar between the 2 groups (3 failures in the TTO group and 2 failures in the iMPFL group; P = .42). In the TTO group, 1 patient experienced a repeat dislocation postoperatively and 2 patients had subjective instability; in the iMPFL group, 2 patients had subjective instability. The prevalence of complications did not differ between the 2 groups ( P = .410). In the subgroup analysis based on TT-TG distance, we did not note any differences in clinical outcomes between iMPFL and TTO groups in subgroups of 15 mm ≤ TT-TG ≤ 20 mm and 20 mm < TT-TG ≤ 25 mm. Conclusion: MPFL reconstruction with and without TTO provided similar, satisfactory clinical outcomes and low redislocation rates for patients who had patellar instability with a TT-TG distance of 15 to 25 mm, without statistical difference. Thus, our findings suggest that iMPFL reconstruction is a safe and reliable treatment for patients with recurrent patellar dislocation with a TT-TG distance of 15 to 25 mm, without the disadvantages derived from TTO.

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How Does Isolated Medial Patellofemoral Ligament Reconstruction Influence Patellar Height?

The American Journal of Sports Medicine ◽

10.1177/0363546520902132 ◽

2020 ◽

Vol 48 (4) ◽

pp. 895-900 ◽

Cited By ~ 1

Author(s):

Francesco Luceri ◽

Julien Roger ◽

Pietro Simone Randelli ◽

Sébastien Lustig ◽

Elvire Servien

Keyword(s):

Patellar Instability ◽

Medial Patellofemoral Ligament ◽

Case Series ◽

Patellofemoral Instability ◽

Patellar Height ◽

Patella Alta ◽

Level Of Evidence ◽

Normal Limits ◽

Patient Reported ◽

History Of

Background: Reconstruction of the medial patellofemoral ligament (MPFL) is the gold standard treatment for recurrent patellar dislocation. Patella alta has been reported in about half of patients with recurrent patellofemoral instability. Hypothesis: MPFL reconstruction (MPFLr) has a beneficial role in the correction of patellar height in patients with mild patella alta (Caton-Deschamps index [CDI] between 1.20 and 1.40). Study Design: Case series; Level of evidence, 4. Methods: Skeletally mature patients, with no history of previous or concomitant knee surgical procedures, who underwent isolated MPFLr using hamstring autograft for recurrent patellar instability between 2005 and 2018, were included in this study. The authors calculated CDI, modified Insall-Salvati index (MISI), and Blackburne-Peel index (BPI) ratios. Measurements done by 2 independent observers were calculated and used to compare pre- and postoperative patellar height (patella alta: CDI >1.20). Results: A total of 89 patients (95 knees) were included in the study, with a mean age of 25.0 years (range, 15.0-45.0 years). There were 70% women and 30% men. We found patella alta in 35.8% of cases preoperatively. Among them, 79.4% had reduced patellar height indices, within normal limits, postoperatively (mean follow-up, 18.4 ± 12.0 months). All the ratios showed a significant reduction in patellar height after surgery (CDI: 0.19 [range, –0.05, 0.60]; MISI: 0.22 [–0.14, 0.76]; BPI: 0.18 [–0.08, 0.59]; P < .00001). The CDI of 79.4% of the study knees was reduced to within normal limits postoperatively. The CDI was maintained within normal limits postoperatively in 93.4% of the knees with normal patellar height and reduced to normal in 50% of the knees with severe patella alta before surgery . No patient reported patella infera before surgery, whereas this condition was found in 8.2% of study patients postoperatively. A moderate correlation was reported between preoperative radiographic indices and their reduction after surgery (CDI: P < .001, ρ = 0.39; MISI: P < .001, ρ = 0.39; BPI: P < .001, ρ = 0.48). Conclusion: The higher the preoperative patellar height, the more important is the lowering effect of MPFLr using the hamstring for patellar instability. Bony procedures should not be indicated in patients with patellar instability and a CDI between 1.20 and 1.40.

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