Prevalence and clinical significance of chondromalacia isolated to the anterior margin of the lateral femoral condyle as a component of patellofemoral disease: observations at MR imaging

Internal Torsion of the Knee: An Embodiment of Lower-Extremity Malrotation in Patients with Patellar Instability

BACKGROUND

Torsion of the lower extremities has been suggested to be a predisposing factor for patellar instability. However, no clear torsional factors have been clarified. This study aimed to elucidate the rotational geometry of the lower limb through segmental analysis in patients with patellar instability.

METHODS

Eighty-three patients with patellar instability were included. Computed tomography of the lower limb was acquired. Femoral and tibial torsion were measured in different segments. Femoral and tibial torsion in each segment was compared between the high- and normal-torsion groups to investigate which segment contributes the most.

RESULTS

All segments of femoral and tibial torsion except proximal femoral torsion showed significant differences between the high- and normal-torsion groups. The average proximal femoral torsion was 1.9° ± 7.1°, indicating that there was only slight torsion in the segment of the femoral neck. The angle between the femoral neck and the foot orientation in the normal-torsion, high-torsion tibial, and combined high-torsion femoral and tibial groups was 89.1° ± 12.0°, 81.3° ± 9.4°, and 98.2° ± 11.7°, respectively (p < 0.001), which suggested that the femoral neck remained nearly perpendicular to the foot orientation in the normal-torsion group. Shaft and distal femoral torsion contributed the most to total femoral torsion. For tibial torsion, from distal to proximal, internal torsion of both the proximal and distal segments contributed to the high torsion. There was no significant difference between distal femoral torsion and proximal tibial torsion, which suggested that, rather than the distal femur rotating internally on its own, the distal femur and the proximal tibia simultaneously rotated internally.

CONCLUSIONS

In patients with patellar instability, torsional deformity occurs along the length of the tibia and in the shaft and distal segments of the femur. The comprehensive embodiment of lower-extremity malrotation is an internal rotation deformity of the knee.

CLINICAL RELEVANCE

This study elucidated the rotational geometry of the lower limb through a detailed segmental analysis in patients with patellar instability. It could serve as a theoretical basis for choosing a derotational osteotomy site and may be a reference for additional clinical research.

Correlation of T2* relaxation times of the retropatellar cartilage with tibial tuberosity-trochlea groove distance in professional soccer players

The tibial tuberosity–trochlear groove (TT–TG) distance is a radiographic measurement that is used to quantify malalignment of the patellofemoral joint (PFJ) in cross-sectional imaging. There is an ongoing debate about the impact of the TT–TG-distance on lateral patellar instability and the initiating of cartilage degeneration. In this prospective study, the association of T2* relaxation times and TT–TG distances in professional soccer players was analyzed. 36 knees of 18 professional soccer players (age: 21 ± 2.8 years) were evaluated. Participants underwent knee MRI at 3 T. For qualitative image analysis, fat-saturated 2D PD-weighted Fast Spin Echo (FSE) and T1-weighted FSE sequences were used. For quantitative analysis, T2* measurements in 3D data acquisitions were performed. In a qualitative analysis there was no structural cartilage damage and no abnormalities of the patellar and trochlea shape. The highest T2* values (26.7 ± 5.9 ms) were observed in the central compartment of the patella. The mean TT–TG distance was 10 ± 4 mm (range 3–20 mm). There was no significant correlation between TT–TG distance and T2* relaxation times in all three compartments of the retropatellar cartilage. Our study shows that so long as patellar and trochlear morphology is normal, TT–TG distance alone does not affect the tissue structure of the retropatellar cartilage in professional soccer players.

Femoral Anteversion Is Related to Tibial Tubercle-Trochlear Groove Distance in Patients with Patellar Dislocation

PURPOSE

To evaluate the potential relationship between the tibial tubercle-trochlear groove (TT-TG) distance and the femoral anteversion of different segments of the femur in patients with patellar dislocation.

METHODS

A total of 60 patients with a diagnosis of patellar dislocation were included in our study. Patients with previous knee surgeries, previous fractures, or lack of necessary radiologic examinations were excluded from our study. The data of computed tomography scanning within a week before the surgery was used to measure the TT-TG distance, total anteversion, proximal anteversion, diaphyseal anteversion, distal anteversion, and tibial torsion. All the data were obtained from the picture archiving and communication system (PACS) workstation. The Pearson correlation analysis was performed to confirm the potential relationship between TT-TG distance and femoral anteversion of different segments. The intraclass correlation coefficient was used to assess the interobserver reliability of measurements.

RESULTS

The TT-TG distance was significantly correlated with the diaphyseal anteversion (r = -0.305, P = 0.008) and distal anteversion (r = 0.365, P = 0.004). The total anteversion was associated with proximal anteversion (r = 0.392, P = 0.02) and diaphyseal anteversion (r = 0.631, P < 0.001). The intraclass correlation coefficient showed the measurements of included parameters were presented with excellent agreement.

CONCLUSION

Our study showed that patients with high diaphyseal anteversion and distal anteversion tend to had a higher TT-TG distance but the value of total and proximal femoral anteversion were independent of the value of TT-TG distance.

LEVEL OF EVIDENCE

Level IV therapeutic case series.

The relationship between early-onset chondromalacia and the position of the patella

Background

There are many underlying accelerator factors for chondromalacia and one of the well-known factors is patellar malalignment.

Purpose

To evaluate the relationship between early-onset chondromalacia and patellar position; and, second, to evaluate the value of patellar malalignment criteria.

Material and Methods

Patients aged 18–40 years with advanced chondromalacia were included. For comparison, a control group was defined with the same number of individuals of the same mean age. The magnetic resonance imaging (MRI) sagittal view with the greatest patellar length was used to obtain the patellar height measurement with the Insall-Salvati index. For the remaining three indices—modified Insall-Salvati, Caton-Deschamps, and Blackburne-Pell—a sagittal view with the greatest patellar articular surface was used. Discordance was defined as contradiction with the measured index and the other three indices.

Results

Both patella alta and baja were found to be predisposing factors for chondromalacia. Modified Insall-Salvati index was the most concordant measurement to define patella alta.

Conclusion

Both patella alta and patella baja were found to predispose to chondromalacia. Patella baja is rare, which may explain why it is not often mentioned as a predisposing factor. The modified Insall-Salvati index ratio was the best patella alta indicator that showed chondral status, more than patellar placement, and was more concordant with the other indices. Blackburne-Pell had the second highest number and ratio of discordance. BP cannot be optimally calculated because deciding the location of the tibial plateau seems to be problematic since it is a three-dimensional and complicated structure.

Sagittal plane tilting deformity of the patellofemoral joint: a new concept in patients with chondromalacia patella

PURPOSE

The aims of this study were to evaluate sagittal plane alignment in patients with chondromalacia patella via magnetic resonance imaging (MRI), analyse the relationships between the location of the patellar cartilaginous lesions and sagittal alignment and finally investigate the relationships between the sagittal plane malalignment and patellofemoral loadings using by finite element analysis.

METHODS

Fifty-one patients who were diagnosed with isolated modified Outerbridge grade 3-4 patellar chondromalacia based on MRI evaluation and 51 control subjects were evaluated. Chondromalacia patella patients were divided into three subgroups according to the chondral lesion location as superior, middle and inferior. The patella-patellar tendon angle (P-PT) was used for evaluation of sagittal alignment of patellofemoral joint. Each subgroup was compared with control group by using P-PT angle. To investigate the biomechanical effects of sagittal plane malpositioning on patellofemoral joint, bone models were created at 30°, 60° and 90° knee flexion by using mean P-PT angles, which obtained from patients with chondromalacia patellae and control subjects. The total loading and contact area values of the patellofemoral joints were investigated by finite element analysis.

RESULTS

The mean age of all participants was 52.9 ± 8.2 years. The mean P-PT angle was significantly lower in chondromalacia group (142.1° ± 3.6°) compared to control group (144.5° ± 5.3°) (p = 0.008). Chondral lesions were located in superior, middle and inferior zones in 16, 20 and 15 patients, respectively. The mean P-PT angles in patients with superior (141.8 ± 2.7) and inferior subgroups (139.2 ± 2.3) were significantly lower than the values in the control group (p < 0.05). The contact area values were detected higher in models with chondromalacia than in the control models at the same flexion degrees. There were increased loadings at 30° and 90° flexions in the sagittal patellar tilt models.

CONCLUSION

This study revealed that sagittal plain malpositioning of the patellofemoral joint might be related to chondromalacia, especially in the presence of lesions in the upper and lower part of the patella. This condition leads to supraphysiological loadings on the patellofemoral joint. Sagittal patellar tilt should be considered in the evaluation and management of patellar cartilage defects. Taking sagittal plane malalignment into consideration in patellofemoral joint evaluation will enable us to design new physical and surgical modalities.

LEVEL OF EVIDENCE

IV.

Increased Magnetic Resonance Imaging Signal of the Lateral Patellar Facet Cartilage: A Functional Marker for Patellar Instability?

BACKGROUND

In the knee joint, predisposition for patellar instability can be assessed by an abnormal Insall-Salvati index, tibial tuberosity-trochlear groove (TTTG) distance, and abnormal shape of patella and trochlea. Given the complex anatomic features of the knee joint with varying positions of the patella during motion, the presence of a single or even a combination of these factors does not inevitably result in patellar instability. After trocheoplasty in patients with trochlear dysplasia, assessment of trochlear cartilage and subchondral bone is limited due to postoperative artifacts. Identification of presence of edema in the patellar cartilage may be helpful to identify patellar instability before and after surgery in these patients.

PURPOSE

To determine whether increased signal intensity of the lateral patellar facet cartilage or measurements of abnormal patellofemoral articulation are associated with patellar instability before and after trochleoplasty.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty-two patients with clinical diagnosis of patellar instability who underwent trochleoplasty, with magnetic resonance imaging (MRI) of the knee before and after surgery, were identified. The following observations and measurements were obtained in preoperative imaging: Insall-Salvati ratio, tibial tuberosity-trochlear groove (TTTG) distance, patellar shape (Wiberg), trochlear shape (Hepp), and edema in the lateral patellar facet cartilage. At 3 to 12 months after surgery, the presence or absence of edema in the cartilage of the lateral facet of the patella, the trochlear shape, and TTTG distance were reassessed. Wilcoxon matched-pairs signed rank test and Student t test were used. Interreader agreement was calculated as the Cohen κ or paired Student t test.

RESULTS

Increased cartilage signal was present in 20 patients before trochleoplasty and in 4 after trochleoplasty. Insall-Salvati ratio was greater than 1.20 in 20 patients. Patellar shape was greater than type 2 in 18 patients. Trochlear shape was greater than type 2 in 21 patients before and 7 after trochleoplasty. Mean TTTG distance was 14 mm before and 10 mm after surgery. When results before and after surgery were compared, a significant difference was found for cartilage signal, TTTG distance, and trochlear shape. Agreement for observations was moderate to substantial, and no significant differences were found for interreader agreement ( P > .05).

CONCLUSION

Patellar cartilage at the lateral facet of the patella can be assessed after trochleoplasty despite postoperative artifacts in the trochlea. A decrease of patellar edema seems to be associated with improved femoropatellar articulation. Moreover, patellar edema may be used as a functional criterion of patellofemoral instability. This would provide additional information compared to morphologic criteria which just describe predisposing factors for femoropatellar instability.

In Vitro and In Vivo Studies of Alar-Nasal Cartilage Using Autologous Micro-Grafts: The Use of the Rigenera® Protocol in the Treatment of an Osteochondral Lesion of the Nose

Cartilage defects represent a serious problem due to the poor regenerative properties of this tissue. Regarding the nose, nasal valve collapse is associated with nasal blockage and persistent airway obstruction associated with a significant drop in the quality of life for patients. In addition to surgical techniques, several cell-based tissue-engineering strategies are studied to improve cartilage support in the nasal wall, that is, to ameliorate wall insufficiency. Nevertheless, there are no congruent data available on the benefit for patients during the follow-up time. In this manuscript, we propose an innovative approach in the treatment of cartilage defects in the nose (nasal valve collapse) based on autologous micro-grafts obtained by mechanical disaggregation of a small portion of cartilage tissue (Rigenera® protocol). In particular, we first analyzed in vitro murine and human cartilage micro-grafts; secondly, we analyzed the clinical results of a patient with pinched nose deformity treated with autologous micro-grafts of chondrocytes obtained by Rigenera® protocol. The use of autologous micro-graft produced promising results in surgery treatment of cartilage injuries and could be safely and easily administrated to patients with cartilage tissue defects.

Abnormal Patella Height Based on Insall-Salvati Ratio and its Correlation with Patellar Cartilage Lesions: An Extremity-Dedicated Low-Field Magnetic Resonance Imaging Analysis of 1703 Chinese Cases

Background and aims:

Diagnostic performance of patellar position for patellar cartilage lesions remains unclear. The aim of this study was to assess the abnormal patella height and its correlation with chondral lesions of the patellofemoral joint in China.

Material and methods:

A total of 1703 consecutive patients who performed knee joint examination using an extremity-dedicated low-field magnetic resonance imaging were enrolled in this study. Patellar cartilage lesions were diagnosed based on the result of magnetic resonance imaging and clinical data. Patella height was defined as the ratio of patellar tendon length to patellar length according to Insall-Salvati index. Patella alta and infera were defined as tendon length/patellar length >1.2 and <0.8, respectively.

Results:

The total prevalence of patellar cartilage lesions was 38.0%. The prevalence in females was significantly higher than that in males (46.4% vs 28.8%, p < 0.001). Age notably increased the incidence of patellar cartilage lesions ( p < 0.001). Logistic regression analysis showed that tendon length/patellar length ratio was significantly correlated with patellar cartilage lesions (odds ratio = 6.380, p < 0.001). Furthermore, patients with cartilage lesions showed significantly higher rates of patella alta and infera ( p < 0.001). In addition, receiver operating characteristic curve analysis demonstrated that abnormal patella height had statistical significance in diagnosing cartilage lesions ( p < 0.001). However, the area under the curve (0.596; 95% confidence interval: 0.568–0.624) and sensitivity (47.0%) were relatively low, while the specificity was 72.2%.

Conclusions:

Patients with patellar cartilage lesions have an increased tendon length/patellar length ratio. The abnormal patella height is significantly correlated with chondral lesions and can be used as a potential diagnostic marker.

Association between patellar cartilage defects and patellofemoral geometry: a matched-pair MRI comparison of patients with and without isolated patellar cartilage defects

PURPOSE

To compare the geometry of the patellofemoral joint on magnetic resonance images (MRI) between patients with isolated cartilage defects of the patella and a gender- and age-matched control group of patients without patellar cartilage defects.

METHODS

A total of 43 patients (17 female, 26 male) with arthroscopically verified grade III and IV patellar cartilage defects (defect group) were compared with a matched-pair control group of patients with isolated traumatic rupture of the anterior cruciate ligament without cartilage defects of the patellofemoral joint. Preoperative MRI images were analysed retrospectively with regard to patellar geometry (width, thickness, facet angle), trochlear geometry (dysplasia according to Dejour, sulcus angle, sulcus depth, lateral condyle index, trochlea facet asymmetry, lateral trochlea inclination) and patellofemoral alignment (tibial tuberosity-trochlear groove distance, patella height, lateral patella displacement, lateral patellofemoral angle, patella tilt, congruence angle). In addition to the comparison of group values, the measured values were compared to normal values reported in the literature, and the frequency of patients with pathologic findings was compared between both groups.

RESULTS

The defect group demonstrated a significantly higher proximal chondral sulcus angle (p < 0.001), a significantly higher distal osseal sulcus angle (p = 0.004), a significantly lower distal sulcus depth (p = 0.047), a significantly lower lateral condyle index (p = 0.045), a significantly lower Caton-Deschamps index (p = 0.020) and a significantly higher Insall-Salvati index (p = 0.010). A major trochlear dysplasia (grade B-D) was significantly more common in the defect group (54 vs. 19%; p < 0.001). Eighty-eight per cent of patients in the defect group demonstrated at least one pathologic finding, compared to 63% in the control group (p = 0.006). Two or more pathologic findings were observed in 42% of the defect group and in 19% of the control group (p = 0.019). There was no significant correlation between the localization of the chondral defects and the results of the measured parameters.

CONCLUSIONS

Cartilage defects of the patella are associated with the geometry of the patellofemoral joint. In particular, a flat and shallow trochlea, trochlea dysplasia and patella alta seem to contribute to the development of patellar cartilage defects, which must be taken into consideration when planning to do surgical cartilage repair at the patella.

LEVEL OF EVIDENCE

III.