scholarly journals Accuracy of tibial tuberosity-trochlear groove distance and tibial tuberosity-posterior cruciate ligament distance in terms of the severity of trochlear dysplasia

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Conglei Dong ◽  
Chao Zhao ◽  
Ming Li ◽  
Chongyi Fan ◽  
Xunkai Feng ◽  
...  

Abstract Purpose Increased tibial tubercle-trochlear groove distance (TT-TG) was proposed as one of the main risk factors for patellofemoral instability (PFI). The increased TT-TG distance indicated externalization of the tibial tubercle with the reference of the trochlear groove. However, in the case of severe trochlear dysplasia, the reference point on the trochlear groove was indistinct, and the accuracy of TT-TG was controversial. The purpose of this study was to evaluate the accuracy of TT-TG and TT-PCL in consideration of the mild and severe trochlear dysplasia. Methods From 2015 to 2020, MRI findings of consecutive knee joints with PFI symptoms diagnosed in our hospital were retrospectively analyzed. All knees with trochlear dysplasia were diagnosed by longitudinal MRI scan and lateral radiograph. The knees were classified according to the four-type classification system described by Dejour et al. Twenty cases of type A (mild trochlear dysplasia); 20 cases of type B, C, and D (severe trochlear dysplasia); and 20 cases of normal type were selected and divided into normal group (normal trochlea), mild group (type A), and severe group (type B, type C, type D). Tibial tubercle-trochlear groove distance (TT-TG), tibial tubercle-posterior cruciate ligament distance (TT-PCL), and the Dejour classification of trochlear dysplasia were assessed by 2 experienced orthopedics. The reliability of TT-TG distance and TT-PCL distance was tested by intraclass correlation coefficients (ICCs). Results Comparing the differences between TT-TG and TT-PCL in the normal, mild, and severe groups, the TT-TG and TT-PCL in the mild and severe groups show different meanings (normal, 8.83 ± 3.62 mm vs. 8.44 ± 4.57 mm, P > 0.05; mild, 17.30 ± 4.81 mm vs. 20.09 ± 5.05 mm, P < 0.05; severe, 10.79 ± 4.24 mm vs. 12.31 ± 5.43 mm, P > 0.05). The Pearson correlation coefficient of TT-TG and TT-PCL measurements of trochlear dysplasia were r = 0.480 (mild group, P = 0.032) and r = 0.585 (severe group, P < 0.001). The intra-observer ICCs of TT-TG were r = 0.814 (mild group) and r = 0.739 (severe group). The inter-observer ICCs of TT-TG were r = 0.810 (mild group) and r = 0.713 (severe group). In the normal knee, the Pearson correlation coefficient of TT-TG and TT-PCL was r = 0.787(P < 0.001), the intra-observer ICC of TT-TG was r = 0.989, and the inter-observer ICC of TT-TG was r = 0.978. Conclusion Compared with the mild trochlear dysplasia, the inter-observer and intra-observer correlations of TT-TG measurements decreased in the group of severe dysplastic trochlea (inter-observer ICC, 0.810 vs. 0.713; intra-observer ICC, 0.814 vs. 0.739). In the present study, the determination of TT-TG and TT-PCL distance are of great significance for patients with low-grade trochlear dysplasia. And TT-PCL, without referring to the abnormal trochlear groove, is an effective indicator to measure the lateralization of tibial tuberosity in patients with severe dysplastic trochlea.

2021 ◽  
Author(s):  
Conglei Dong ◽  
Chao Zhao ◽  
Ming Li ◽  
Chongyi Fan ◽  
Xunkai Feng ◽  
...  

Abstract Purpose Increased Tibial Tubercle-Trochlear Groove Distance (TT-TG) was proposed as one of the main risk factors for patellofemoral instability (PFI). The increased TT-TG distance indicated externalization of the tibial tubercle with the reference of the trochlear groove. However, in the case of severe trochlear dysplasia, the reference point on the trochlear groove was indistinct, and the accuracy of TT-TG was controversial. The purpose of this study was to evaluate the accuracy of TT-TG and TT-PCL in consideration of the mild and sereve trochlear dysplasia . Methods From 2015 to 2020, MRI findings of consecutive knee joints with PFI symptoms diagnosed in our hospital was retrospectively analyzed. All knees with trochlear dysplasia were diagnosed by longitudinal MRI scan and lateral radiograph. The knees were classified according to the four-type classification system described by Dejour et al. 20 cases of type A (mild trochlear dysplasia), 20 cases of type B, C, and D (severe trochlear dysplasia), and 20 cases of normal type were selected and divided into normal group (normal trohlea), mild group (type A) and severe group (type B, type C, type D). Tibial Tubercle-Trochlear Groove Distance (TT-TG), Tibial Tubercle-Posterior Cruciate Ligament Distance (TT-PCL), and the Dejour classification of trochlear dysplasia was assessed by 2 experience orthopaedics. The the reliability of TT-TG diatance and TT-PCL distance was tested by intraclass correlation coefficients (ICC).Results Comparing the differences between TT-TG and TT-PCL in the normal, mild and severe groups, the TT-TG and TT-PCL in the mild and severe group show different meanings. (normal, 8.83±3.62 mm vs. 8.44±4.57mm, P>0.05;mild, 17.30±4.81 mm vs. 20.09±5.05mm, P<0.05;severe, 10.79±4.24 mm vs. 12.31±5.43mm, P>0.05). The Pearson correlation coefficient of TT-TG and TT-PCL measurements of trochlear dysplasia were r=0.480 (mild group, P=0.032), r=0.585 (severe group, P<0.001). The Intra-observer ICC of TT-TG were r=0.814 (mild group), r=0.739 (severe group). The Inter-observer ICC of TT-TG were r=0.810 (mild group), r=0.713 (severe group). In the normal knee, the Pearson correlation coefficient of TT-TG and TT-PCL was r=0.787(P<0.001), the Intra-observer ICC of TT-TG was r=0.989, and the Inter-observer ICC of TT-TG was r=0.978. Conclusion Compared with the mild trchlear dysplasia, the inter-observer and intra-observer correlations of TT-TG measurements decreased in group of sereve dysplastic trochlea (Inter-observer ICC, 0.810 vs. 0.713; Intra-observer ICC , 0.814 vs. 0.739). In the present study, the determination of TT-TG and TT-PCL distance are of great significance for patients with low grade trochlear dysplasia. And TT-PCL, without referring to the abnormal trochlear groove, is an effective indicator to measure the lateraltization of tibial tuberosity in patients with sereve dysplastic trochlea.


2020 ◽  
Vol 8 (6) ◽  
pp. 232596712092548
Author(s):  
Matthew Colatruglio ◽  
David C. Flanigan ◽  
Sarah Harangody ◽  
Robert A. Duerr ◽  
Christopher C. Kaeding ◽  
...  

Background: Recurrent patellar instability is frequently treated surgically with reconstruction of the medial patellofemoral ligament (MPFL). Patients with significant patella alta, trochlear dysplasia, and/or an elevated tibial tubercle–trochlear groove (TT-TG) distance may benefit from a concurrent bony procedure such as tibial tubercle osteotomy or trochleoplasty. The indications to perform such procedures are traditionally based on imaging criteria but remain controversial. Patellar apprehension is common in patients with patellar instability but typically resolves in higher degrees of knee flexion. Hypothesis: The persistence of patellar apprehension at greater than 60° of knee flexion is associated with patella alta, an increased TT-TG distance, and trochlear dysplasia. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 76 patients with recurrent patellar instability were prospectively identified in a sports medicine clinic. Patellar apprehension was evaluated in each patient. Apprehension was defined as the patient reporting that the patella felt unstable to lateral patellar translation. Apprehension was first assessed at full knee extension and repeatedly assessed as the knee was flexed in 10° intervals, as measured using a goniometer. The degree of flexion at which patellar apprehension disappeared was recorded. Plain radiographs and magnetic resonance imaging (MRI) scans were obtained for all patients. Patellar height was assessed with the Caton-Deschamps (CD) index, and trochlear morphology was assessed through measurements of the sulcus angle and depth on MRI and classified using the Dejour classification system. Imaging measurements of patients in whom apprehension resolved by 60° of knee flexion were compared with measurements for those with apprehension that persisted deeper into flexion. Results: Apprehension resolved by 60° of flexion in 56 patients and persisted into deeper flexion in 20 patients. The patients with a delayed resolution of apprehension demonstrated a higher CD index; elevated TT-TG distance; increased sulcus angle; decreased sulcus depth; and higher incidence of Dejour type B, C, or D dysplasia (all P < .05). Of the 20 patients with a delayed resolution of apprehension, 18 had either Dejour type B, C, or D dysplasia or a CD index of at least 1.30. A delayed resolution of apprehension was present in 11 of the 16 patients with Dejour type B, C, or D dysplasia. Conclusion: Overall, 90% of patients with significant patella alta and the majority of patients with high-grade trochlear dysplasia demonstrated patellar apprehension that persisted beyond 60° of knee flexion. Additionally, 90% of patients with persistent apprehension had significant patella alta and/or trochlear dysplasia. Further work is needed to evaluate the utility of these findings to inform surgical decision-making in this population.


2018 ◽  
Vol 6 (7_suppl4) ◽  
pp. 2325967118S0007 ◽  
Author(s):  
David Bernholt ◽  
Joseph D. Lamplot ◽  
Eric Eutsler ◽  
Jeffrey J. Nepple

Objectives: Lateralization of the tibial tubercle plays a significant role in the pathophysiology of patellar instability and is most often assessed by the tibial tubercle to trochlear groove distance (TT-TG) measured on CT or MRI with the knee in extension. However, tracking of the patella in 30 to 45 degrees of flexion has been suggested to be of greater clinical significance. Merchant radiographs can demonstrate the position of the tibial tubercle relative to the trochlear groove in this range of flexion and thus may serve as a valuable tool in the assessment of patellar tracking. The purpose of the current study was (1) to validate radiographic assessment of the merchant view TT-TG and (2) to determine the correlation with MRI-based measurements. Methods: To validate Merchant TT-TG as a marker of the position of the tibial tubercle, 41 patients between the ages of 10-18 had standardized Merchant radiographs in 45 degrees flexion yielding imaging of 82 knees. Lead markers were placed upon the skin centered over the tibial tubercle based on palpation. Radiographs were collected and analyzed. The TT-TG was measured as the distance between lines centered over the deepest point of the trochlear groove and the center of the tibial tubercle and perpendicular to the anterior condylar axis. In order to correlate Merchant TT-TG to MRI TT-TG, 16 additional patients were added to reach a total of 30 patients with a Merchant radiograph and MRI, as power calculation determined 29 knees needed to detect a Pearson correlation coefficient (PCC) of .500. There was excellent interobserver reliability between two readers for Merchant TT-TG with and without use of a radiographic marker (ICC = .975 and .923 respectively). Results: The tibial tubercle could be identified on Merchant radiograph in 67 images (81.7%). Merchant TT-TG measured with use of a marker was very strongly correlated measurement based on bony landmarks alone (PCC = .848). The Merchant TT-TG measured with bony landmarks alone was strongly correlated to MRI TT-TG (PCC = .602). The strength of this correlation was increased by standardizing TT-TG by patellar width (PCC = .710). MRI TT-TG was increased in patients with patellar instability at 13.9 mm compared to 10.5 mm (p <.01); Merchant TT-TG was also increased in patients with patellar instability at 9.1 mm compared to 1.9 mm (p < .001). Conclusion: Standardized Merchant radiographs without radiographic markers allow for assessment of TT-TG in the majority of patients. Merchant TT-TG strongly correlates with MRI TT-TG but measured 5-8 mm smaller than MRI TT-TG.


2020 ◽  
Vol 8 (5_suppl4) ◽  
pp. 2325967120S0029
Author(s):  
Felix Zimmermann ◽  
Peter Balcarek

Aims and Objectives: The medial patellofemoral ligament (MPFL) is the most important passive stabilizer of the patella. In recurrent lateral patellar dislocations reconstruction of the MPFL with an autologous tendon transplant is a frequently performed surgical procedure that shows a low redislocation rate between 1%-7%. However, a complication rate of up to 26% and a reoperation rate of 4% has also been observed. The question, therefore, arises which parameter determines MPFL reconstruction failure. Thus, the purpose of this study was to identify reasons for MPFL reconstruction failure with regard to patients’ complaints leading to reoperation. Materials and Methods: Between July 2015 and May 2019 28 patients (M/F 9/19; mean age 27 ± 8 years) with postoperative complaints after MPFL reconstructive surgery had to undergo revision surgery. Preoperative failure analysis included clinical examination (ROM, ReDPAT, J-sign, and Patella-Glide Test) and radiological imaging with regard to anatomical risk factors of patellar instability and MPFL tunnel positioning. Anatomical predisposition was assessed according to Dejour’s classification of trochlear dysplasia, tibial tuberosity-trochlear groove distance, tibial tuberosity-posterior cruciate ligament distance, patellar height, varus/valgus malalignment and torsional profile. Results: Three major reasons for revision surgery were identified: (1) patellar redislocation, (2) limited range of motion (ROM), and (3) anterior knee pain (AKP). Sixteen of the 28 patients (57%) suffered from recurrent patellar dislocation. Severe trochlear dysplasia (type B/D according to Dejour) (44%), valgus deformity (19%), increased patellar height (19%), and misplaced femoral drill channels (31%) could be identified as risk factors for redislocation. An increased TT-TG (>20mm) or TT-PCL (>24mm) distance could not be observed in any patient in this group. Limited ROM with an average maximum flexion ability of about 92 ± 26° was observed in 10 of the 28 patients (36%), of which 9 patients additionally complained of AKP. Misplaced femoral drill channels (80%), severe trochlear dysplasia (type B/D according to Dejour) (20%) and postoperative decreased patellar height (20%) could be identified as risk factors for postoperative limited ROM. Other reasons for postoperative AKP were increased femoral antetorsion (n=1) and retropatellar cartilage damage (n=2) without any loss of ROM. Conclusion: Recurrent dislocation of the patella, limited ROM and AKP were identified as most common complications after MPFL reconstruction leading to revision surgery. Failures are mainly due to neglected bony risk factors of patellar instability (trochlear dysplasia, patella alta and valgus deformity) and to misplaced femoral drill channels. Appropriate patient selection and an accurate surgical technique appear mandatory for a good clinical outcome when patellar instability is treated solely with an MPFL reconstruction.


2019 ◽  
Vol 7 (6_suppl4) ◽  
pp. 2325967119S0022
Author(s):  
Peter Balcarek ◽  
Dennis Vogel

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.


2021 ◽  
pp. 036354652098781
Author(s):  
Mathias Paiva ◽  
Lars Blønd ◽  
Per Hölmich ◽  
Kristoffer Weisskirchner Barfod

Background: Tibial tubercle–trochlear groove (TT-TG) distance is often used as a measure of lateralization of the TT and is important for surgical planning. Purpose: To investigate if increased TT-TG distance measured on axial magnetic resonance images is due to lateralization of the TT or medialization of the TG. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 84 knees (28 normal [NK], 28 with trochlear dysplasia [TD], and 28 with patellar dislocation without TD [PD]) were examined. The medial border of the posterior cruciate ligament (PCL) was chosen as the central anatomic landmark. The distance from the TT to PCL (TT-PCL) was measured to examine the lateralization of the TT. The distance from the TG to the PCL (TG-PCL) was measured to examine the medialization of the TG. Between-group differences were investigated by use of 1-way analysis of variance. Results: The mean values for TT-TG distance were 8.7 ± 3.6 mm for NK, 12.1 ± 6.0 mm for PD, and 16.7 ± 4.3 mm in the TD group ( P < .01). The mean values for TT-PCL distance were 18.5 ± 3.6 mm for NK, 18.5 ± 4.5 mm for PD, and 21.2 ± 4.2 mm in the TD group ( P = .03). The mean values for TG-PCL distance were 9.6 ± 3.0 mm for NK, 7.1 ± 3.4 mm for PD, and 5.1 ± 3.3 mm in the dysplastic group ( P < .01). Conclusion: The present results indicate that increased TT-TG distance is due to medialization of the TG and not lateralization of the TT. Knees with TD had increased TT-TG distance compared with the knees of the control group and the knees with PD. The TT-PCL distance did not differ significantly between groups, whereas the TG-PCL distance declined with increased TT-TG.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zhe Li ◽  
Guanzhi Liu ◽  
Run Tian ◽  
Ning Kong ◽  
Yue Li ◽  
...  

Abstract Background Our objective was to obtain normal patellofemoral measurements to analyse sex and individual differences. In addition, the absolute values and indices of tibial tuberosity-trochlear groove (TT-TG) distances are still controversial in clinical application. A better method to enable precise prediction is still needed. Methods Seventy-eight knees of 78 participants without knee pathologies were included in this cross-sectional study. A CT scan was conducted for all participants and three-dimensional knee models were constructed using Mimics and SolidWorks software. We measured and analysed 19 parameters including the TT-TG distance and dimensions and shapes of the patella, femur, tibia, and trochlea. LASSO regression was used to predict the normal TT-TG distances. Results The dimensional parameters, TT-TG distance, and femoral aspect ratio of the men were significantly larger than those of women (all p values < 0.05). However, after controlling for the bias from age, height, and weight, there were no significant differences in TT-TG distances and anterior-posterior dimensions between the sexes (all p values > 0.05). The Pearson correlation coefficients between the anterior femoral offset and other indexes were consistently below 0.3, indicating no relationship or a weak relationship. Similar results were observed for the sulcus angle and the Wiberg index. Using LASSO regression, we obtained four parameters to predict the TT-TG distance (R2 = 0.5612, p < 0.01) to achieve the optimal accuracy and convenience. Conclusions Normative data of patellofemoral morphology were provided for the Chinese population. The anterior-posterior dimensions of the women were thicker than those of men for the same medial-lateral dimensions. More attention should be paid to not only sex differences but also individual differences, especially the anterior condyle and trochlea. In addition, this study provided a new method to predict TT-TG distances accurately.


2021 ◽  
Author(s):  
Conglei Dong ◽  
Chao Zhao ◽  
Ming Li ◽  
Huijun Kang ◽  
Kang Piao ◽  
...  

Abstract BackgroundThe objective of present study was to investigate the operative effect of patellofemoral arthroplasty combined with the tibial tubercle transfer for isolated patellofemoral arthritis patients with an increased tibial tuberosity-trochlear groove distance (>20mm). MethodsA prospective study was performed between November 2012 and December 2017. Finally, thirty-six cases, with a mean age of 61.1 ± 7.3 years, were admitted to our study. A total of 17 patients underwent patellofemoral arthroplasty combined with tibial tubercle transfer, and 19 patients underwent patellofemoral arthroplasty only. All eligible patients had CT scans preoperatively and at 12 months follow-up, to assess the stability of the patellofemoral joint on axial slices. In addition, the demographic and clinical features of all the patients were asked. Knee balance was assessed with the single leg stance test and timed get up and go, and functionality was evaluated with stair climbing test and the Western Ontario and McMaster Universities Osteoarthritis Index score. (P>0.05) ResultsPreoperatively, the data regarding the knee balance and functionality were not significantly different between the two Groups (P>0.05). Many measurements showed significant differences between the two groups at the last follow-up. Significant differences were seen in well-known measurements such as the SLST (Group I, 28.9 s (SD 7.5); Group II, 20.3 s (SD 5.9); p < 0.001), TGUG (Group I, 13.4 s (SD 3.2); Group II, 16.8 s (SD 3.1); p < 0.001), and SCT (Group I, 18.6 s (SD 6.8); Group II, 24.5 s (SD 8.7); p < 0.001). Additionally, the median WOMAC score was improved from 62.7 (SD 11.2) preoperatively to 25.7 (SD 8.2) one year postoperatively in Group I and from 64.1 (SD 10.7) to 36.2 (SD 9.7) in Group II, which were also significantly different between the groups. ConclusionsFor such special IPA patients with an increased TT-TG (>20mm), the combined operation of PFA combined with TTT can better restore the involutional relationship of patellofemoral joint and further improve the balance and function of knee joint.


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