Patellar Width Research Articles

Analysis of Risk Factors on Patellofemoral Osteoarthritis: Distribution Characteristics and Radiographic Parameters of Patellofemoral Joint.

The risk factors for the degeneration of the patellofemoral joint (PFJ) have not been adequately and thoroughly studied. This study aimed to analyze the population distribution characteristics of patients with patellofemoral osteoarthritis (PFOA) and assess the correlation between PFOA and radiological parameters, including patella morphology, PFJ congruity, and patellar alignment. Moreover, the risk factors across various demographic groups were further analyzed. A retrospective analysis was conducted to examine the population distribution characteristics of PFOA patients from September 2020 to September 2023. Radiological parameters of the PFJ were measured from the anteroposterior and lateral views of knee joint as well as axial view of patella using X-ray imaging and the PACS imaging system at the First Affiliated Hospital of Kunming Medical University. These parameters included patella morphology (patella type, width, thickness, and Wiberg index), PFJ congruity (patella height, Wiberg angle, sulcus angle, and lateral patella angle), and patellofemoral alignment (patella tilt angle, displacement, and lateral patellofemoral angle). PFOA severity was classified according to the Iwano PFJ radiological classification, and its correlation with the aforementioned parameters was examined. Additionally, risk factors for PFOA across different populations were further evaluated. The study included 1080 patients according to the inclusion and exclusion criteria. Age, female gender, overweight or obesity, and manual workers were significantly associated with PFOA. Moreover, type III patella (OR = 3.03, p < 0.05), greater patella width (OR = 1.12, p = 0.01), sulcus angle (OR = 1.04, p < 0.01), patella tilt angle (OR = 1.13, p < 0.01), and patella displacement (OR = 1.22, p < 0.01) as well as smaller patella thickness (OR = 0.87, p < 0.01), Insall-Salvati index (OR = 0.24, p = 0.04), and lateral patellofemoral angle (OR = 0.93, p = 0.02) were identified as risk factors for PFOA. Furthermore, greater patella thickness (OR = 1.17, p < 0.05) and smaller patella displacement (OR = 0.79, p < 0.01) correlated with higher Kujala patellofemoral scores. Discrepancies in risk factors across different populations were also observed. Older age, female gender, obesity, manual workers, and specific aberrations in patellofemoral parameters are predictive factors for PFOA. Additionally, greater patella thickness and smaller patella displacement were associated with increased severity of clinical symptoms. Thus, more attention should be paid to the discrepancies that exist in different populations.

Ratio of Tibial Tubercle-Trochlear Groove Distance to Patellar Width as a Predictor of Patellar Dislocation: Analysis of Individualized Tibial Tubercle Lateralization Parameters.

Available conventional tibial tubercle lateralization (TTL) parameters fail to account for individual patient size or anatomy. To evaluate the predictive ability of individualized TTL parameters and clarify the best predictor of patellar dislocation (PD) and to determine the relationship of the best predictor with other risk factors of PD with quadriceps isotonic contraction. Cohort study (diagnosis); Level of evidence, 2. A total of 15 patients with PD (28 knees) and 14 controls (28 knees) underwent 4-dimensional computed tomography, and the image with the knee fully extended and quadriceps isotonically contracted was selected for evaluation. The following TTL parameters were measured on the images: tibial tubercle-trochlear groove (TT-TG) distance, tibial tubercle-Roman arch distance, and tibial tubercle-posterior cruciate ligament distance, as well as their ratios to femoral condylar width and patellar width (PW). In addition, the following parameters were measured: Insall-Salvati ratio, Blackburne-Peel ratio, Caton-Deschamps ratio, modified Insall-Salvati ratio, bisect offset index, congruence angle, lateral patellar tilt, lateral trochlear inclination, sulcus depth, sulcus angle, trochlear groove medialization, patella-patellar tendon angle, patellofemoral axis angle (P-FAA), patellar articular facet-patellar tendon angle, patellar articular facet-femoral axis angle (PA-FAA), and patellar shape according to Wiberg type. The area under the receiver operating characteristic curve (AUC) was calculated to access the diagnostic accuracy of the TTL parameters for PD, and the TTL parameters with high diagnostic ability were evaluated for correlation with the remaining parameters. The TT-TG/PW ratio had the best diagnostic ability for PD (AUC = 0.890). The TT-TG/PW ratio was positively correlated with bisect offset index, congruence angle, lateral patellar tilt, P-FAA and PA-FAA (r = 0.610, 0.465, 0.635, 0.553 and 0.418, respectively; P≤ .027 for all), and TT-TG/PW ratio was greater in knees with type II versus type III patella (P = .017). With the knee fully extended and quadriceps isotonically contracted, the TT-TG/PW ratio was found to be the best predictor of PD and reflected individualized TTL, which helps with clinical preoperative planning.

MRI analysis of the physiological patellofemoral joint morphology of adult knees.

The aim of the present study was to determine physiological reference values for the morphology of the patella and to analyse these parameters according to patella position in healthy knee joints. Healthy knee joints of 409 patients (mean age, 52.3years [± 16.8]) were analysed retrospectively on MRI images for Insall-Salvati index (ISI), sagittal patella thickness (PTS) and patella length (PLS) as well as axial patella thickness (PTA) and patella width (PWA). Differences between patellar diameters were analysed depending on ISI, side, age and gender. Mean PTS was 20.1 mm (± 2.4), PLS 44.0 mm (± 4.4), PTA 21.8 mm (± 2.4) and PWA 44.5 mm (± 4.7). Depending on the vertical patellar position (ISI), all patellar parameters (p < 0.01) showed significant differences between patients with a patella alta, norma and baja. In general, a smaller ISI showed higher measured values for the patellar parameters. There were no significant differences for the laterality. Only PTS showed a significant age difference (p = 0.031). All parameters were significantly larger in male compared to female knees (p < 0.001). Reference parameters for the patella morphology are reported. Concluding from the results, a relationship between vertical patellar position and patellar morphology seems to exist. This finding should be taken into account in diagnostics and therapy of patella disorders.

Computed Tomographic Measurement Method for Morphoanatomical Comparison of Femur, Tibia, and Patella in Cats with and without Medial Patellar Luxation.

The aims of this study are to describe a computed tomographic (CT) measurement method of feline femoral, tibial, and patellar conformation, and to compare these measurements between a cat population diagnosed with medial patellar luxation (MPL) and cats without MPL. Eleven measurements were performed by two observers, including anatomical lateral distal femoral angle (aLDFA), femoral trochlear width (FTW) and femoral trochlear depth (FTD), anteversion angle of the femoral neck, patellar length, patellar width, patellar height, patellar volume, mechanical medial proximal tibial angle, tibial torsion angle, and tibial tuberosity displacement. Mean and standard deviation differences between the groups were statistically assessed. Intraobserver and interobserver interclass correlation coefficients (ICCs) were calculated. The aLDFA was significantly higher in the MPL II compared with the control and MPL III. The FTW was significantly larger in the MPL III than in the control or the MPL II group. The FTD in the control group was significantly larger than in the MPL II and III groups. The TTA of the control group was significantly smaller than the MPL II and III. The intraobserver ICC was high at 64%, and the interobserver ICC was high at 36% of the measurements. This study identified shallower FTD and increased TTA in cats diagnosed with MPL. The TTA difference was less than 5 degrees and FTD was less than 1 mm. The findings provide information on feline pelvic limb morphology. However, the differences between the two populations are small.

Design and Evaluation of Kirschner Wire Guide Device for Patellar Fracture Fixation

Abstract Identifying the optimal position for Kirschner wire (K-wire) is crucial in tension band wiring for patellar fracture. This study analyzed the ideal position and designed a guide device to aid precise K-wire insertion. The stress and displacement at 90&amp;amp;amp;#176; of flexion were compared to determine the optimal positions. The number of insertions and fluoroscopies, and operating times were recorded in a retrospective study. Intraoperative radiographs were used to measure the K-wire position relative to the patella in the coronal and sagittal planes to assess accuracy. The least stability occurred when the distance between the K-wires was 1/2 of the patellar width in the coronal plane and close to the patellar anterior surface. The number of K-wire insertions in the experimental group and control group (1.33 ±0.58 vs 3.8 ±1.03; P = 0.009), the number of fluoroscopies (2.67 ±0.58 vs 10 ±1.33; P = 0.007), and the operating time (55 ±8.66 min vs 82 ±9.49 min; P = 0.001) were significantly different. K-wires should parallel to each other, spaced 1/4 or 1/3 of the patellar width in the coronal plane, and 1/2 to 3/4 of the patellar thickness in the sagittal plane away from the patellar anterior surface. The surgeon could improve insertion accuracy with guide device.

The Importance of Medial Patellar Shape as a Risk Factor for Recurrent Patellar Dislocation in Adults

Background: Research on the cause of lateral patellar dislocation (LPD) has focused on trochlear morphologic parameters, joint alignment, and patellofemoral soft tissue forces. A paucity of information is available regarding how patellar morphologic parameters influence the risk for LPD. Purpose/Hypothesis: The purpose was to assess whether patellar morphology is a risk factor for recurrent LPD. It was hypothesized that (1) patients with recurrent LPD would have decreased patellar width and volume and (2) patellar morphologic parameters would accurately discriminate patients with recurrent LPD from controls. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: A total of 21 adults with recurrent LPD (age, 29.7 ± 11.1 years; height, 170.8 ± 9.9 cm; weight, 76.1 ± 17.5 kg; 57% female) were compared with 21 sex- and height-matched controls (age, 27.2 ± 6.7 years; height, 172.0 ± 10.6 cm; weight, 71.1 ± 12.8 kg; 57% female). Three-dimensional axial fat-saturated magnetic resonance imaging scans were used to measure patellar medial, lateral, and total width; patellar volume; patellar medial and lateral facet length; the Wiberg index; and previously validated knee joint alignment and femoral shape measurements (eg, tibial tuberosity to trochlear groove distance, trochlear dysplasia). Results: The LPD group demonstrated reduced medial patellar width (Δ = −3.6 mm; P < .001) and medial facet length (Δ = −3.7 mm; P < .001) but no change in lateral width or facet length. This resulted in decreased total patellar width (Δ = −3.2 mm; P = .009), decreased patellar volume (Δ = −0.3 cm3; P = .025), and an increased Wiberg index (Δ = 0.05; P < .001). No significant differences were found for all other patellar shape measures between cohorts. Medial patellar width was the strongest single discriminator (83.3% accuracy) for recurrent LPD. Combining medial patellar width, patellofemoral tilt, and trochlear groove length increased the discrimination to 92.9%. Conclusion: The medial patellar width was significantly smaller in patients with recurrent LPD and was the single most accurate discriminator for recurrent LPD, even compared with traditional trochlear shape and joint alignment measures (eg, trochlear dysplasia, patella alta). Therefore, medial patellar morphology should be assessed in patients with LPD as a risk factor for recurrence and a potential means to improve treatment.

Exploring osteochondral damage patterns in acute patellar dislocation: insights into morphological associations and risk factors

Osteochondral damage (OD) is a significant outcome following acute patellar dislocation (APD), yet the factors contributing to its susceptibility remain unclear. The primary objective of this study was to assess the association between demographic characteristics, patellofemoral (PF) joint morphology, and the occurrence of OD. A retrospective analysis identified 74 patients with APD who underwent treatment in our unit between 2019 and 2022. All patients received MRI within a week of injury to assess OD, subsequently categorized according to the injury pattern. The Caton-Deschamps index (CDI), tibial tuberosity-trochlear groove distance (TT-TG), lateral trochlear inclination (LTI), sulcus angle (SA), patellar width (PW), patellar thickness (PT), and femoral condyle geometry were calculated from the MRI scans and compared between groups. The findings revealed that OD predominantly manifested in the lateral femoral condyle (LFC) region and the medial patella (MP) region. In our patient cohort, this study identified a significant association between sulcus angle and the incidence of OD in both MP and LFC regions. Additionally, a significant correlation was discerned between skeletal maturity and the incidence of OD in the LFC region within demographic characteristics.

Relationships between position of patellar ridge high point and morphology of resected surface for patellar resurfacing in total knee arthroplasty.

Reproducing the native patellar ridge high point while maximizing osseous coverage is important for the success of patellar replacement, but it cannot always be achieved simultaneously. This study aimed to thoroughly investigate the relationships and their influencing factors between the positions of the high point of patellar ridge (HPPR) and the morphology of the patellar resected surface. Four hundred seventy-three patients (265 men, 208 women) aged 18 to 50 years with knee injuries before arthroscopy were retrospectively collected for this cross-sectional study. Computed tomography (CT) and magnetic resonance imaging (MRI) were used to construct 3D computer models of the patella and patellar cartilage. The morphometric characteristics of the patellar cut after virtual resection and the HPPR position relative to the patellar cut centre were measured and analyzed. The medial displacements of the HPPR were positively correlated with Wiberg's classification and index (all P<0.001). The mean values of HPPR's medial displacements were 0.15 of the medial width of patellar cut, and 93.2% of all patella ranged from 0 to 0.3. When the implant's apex were placed at 0.15 of the medial width of patellar cut medialized, the proportion of implant placement errors within 1 mm of the native high point was 12% more in female patella (P=0.01), and 7% more in all patella (P=0.03) than 3 mm medialized. Wiberg's system can roughly predicted the medial-lateral position of the HPPR. The HPPR was mainly medially located at the 0.15 of the medial patellar width approximately, and 15% medialized of the implant's apex can better reproduce the native patellar high point than 3 mm medialized. The current results provide basic data for patellar implant selection, preoperative planning, and implant design to reproduce the native patellar high point better while maximizing osseous coverage for patellar resurfacing.

Anatomic differences in patellar dimensions: A comparative study of left and right sides

The patella is an important bone in the knee joint, and its morphology can vary between different populations. The present study aimed to perform a morphometric analysis of dry human patellae from the Kashmiri population to determine their anatomical features and to compare them with Indian and global studies.The study included 40 dry human patellae (20 right and 20 left) from the Kashmiri population. Various parameters such as patella height, patella width, patella thickness, ridge length, medial and lateral articular facet length and width were measured using a digital Vernier caliper. The mean values of these parameters, along with their standard deviations, minimum and maximum values were calculated. The t-value and p-value were also calculated to determine the significance of any differences observed between the two sides.The results showed no significant differences between the right and left patellae for most of the parameters analyzed, including patella height, patella width, patella thickness, ridge length, medial and lateral articular facet length. However, there was a significant difference in the medial articular facet width (p=0.136) and lateral articular facet width (p=0.318) between the two sides. The mean values for all parameters were within the range of values reported in previous studies of patellar morphology in different populations.The present study provides important information about the morphometric features of patellae in the Kashmiri population. The findings suggest that there are no significant differences in the morphological features of the patellae between the right and left sides, except for the medial and lateral articular facet widths.

A MORPHOMETRIC STUDY OF PATELLA IN LUCKNOW REGION

Background: Patella is the largest sesamoid bone which develops in the tendon of Quadriceps femoris muscle and protects the front of knee joint. It has gained anatomical, clinical &amp; forensic significance due to its vital role in patellofemoral mechanics and its property of resistance to post mortem changes. Aims and Objectives: Our study aims to measure the various dimensions of left and right human patella which can be useful for the manufacture of patellar prosthesis, better suited to Indian population, in contrast to already available prosthesis which are mostly based on the western anthropometric measurements. Methods: The study involves 100 dry human patellae, 50 each from left and right sides. Total patellar height, maximum height of articular surface, maximum width, maximum thickness, shape, width of medial and lateral articular facets of patella were measured using digital Vernier calipers. Mean and standard deviation were calculated for each parameter for left and right sides and the data was analyzed using SPSS. Results: The mean of patellar width on left side came out to be 41.65± 2.78, while for right side, the mean of patellar width was observed to be 42.83± 3.02. A statistically significant difference was observed in patellar width of left and right sides (p= 0.044). Conclusion: Anthropometric study of patella in India can thus be helpful in designing femoropatellar prosthesis for our population leading to better post-operative outcome.

Changes in Patellar Morphology Following Soft Tissue Surgical Correction of Recurrent Patellar Dislocation in Children with Low-Grade Trochlear Dysplasia.

ObjectiveTo investigate the changes in patellar morphology following soft tissue surgical correction of recurrent patellar dislocation in children with low‐grade trochlear dysplasia.MethodsThe prospective cohort study was performed between November 2007 and December 2012. Finally, 25 cases, with the mean age of 8.4 years (range from 7 to 10 years), were admitted to the study. All patients were diagnosed as bilateral recurrent patellar dislocation associated with femoral trochlear dysplasia. The knee that suffered injury or was dislocated was treated with medial patellar retinacular plasty (surgery group). The contralateral knee, which served as a control, was treated conservatively (conservative group). Axial CT scans were undertaken in all patients to assess the patellar morphological characteristics.ResultsThe mean follow‐up time was 60.8 months (range 48 to 75 months). Preoperatively, there were no statistically significant differences between the patellar morphology in the two groups (P > 0.05). Many radiological parameters of patellar morphology were significantly different between the two groups at the final follow‐up, including well‐known parameters, such as the mean patellar width (surgery group, 40.58 mm [SD 1.26]; conservative group, 36.41 mm [SD 1.17]; P < 0.05), the mean patellar thickness (surgery group, 11.59 mm [SD 0.74]; conservative group, 9.38 mm [SD 0.56]; P < 0.05) and the mean Wiberg index (surgery group, 0.54 [SD 0.06]; conservative group, 0.72 [SD 0.08]; P < 0.05). There are also little‐known parameters, such as the ratio of length of lateral patella to medial patella (surgery group, 1.26 [SD 0.17]; conservative group, 1.69 [SD 0.21]; P < 0.05), which was a measurement of facet asymmetry. However, the Wiberg angle was not significantly different between the two groups (surgery group, 128.63° [SD 9.05]; conservative group, 125.47° [SD 13.96°]; P > 0.05) at the final follow‐up. No complications were found.ConclusionsThe patellar morphology can be significantly improved by early soft tissue surgical correction in children with patellar instability associated with low‐grade femoral trochlear dysplasia.

Quantifying the Relationship Between the Medial Patellofemoral Complex and Patellar Borders: A Pediatric Cadaveric Study

Background:The medial patellofemoral complex (MPFC) is comprised of the medial quadriceps tendon-femoral ligament (MQTFL) superiorly and the medial patellofemoral ligament (MPFL) inferiorly. The anatomy of the pediatric MPFL has been well-described, however, the MPFC in skeletally immature patients and its relationship to the quadriceps tendon and superior patellar border has yet to be described.Purpose:To evaluate the relationship between the MPFC attachment and quadriceps tendon and patella in skeletally immature patients.Methods:16 pediatric knees were dissected to analyze the MPFC insertion on the quadriceps tendon. Dissection was performed using a lateral parapatellar arthrotomy followed by eversion of the extensor mechanism to evaluate the MPFC fibers from its undersurface. The patellar articular length (PL), patellar width, and quadriceps tendon attachment (QTA) of the MPFC above the superior pole of the patella were measured using the ImageJ program. Additionally, the ratio of quadriceps tendon attachment to patellar length was calculated as a percent (QTA/PL%). Two sample t-tests were used to identify significant differences.Results:The average age of the specimens included in this study was 9.6 years. Specimens were divided into two cohorts: a younger cohort (4-8 years), and an older cohort (9-12 years). The QTA above the patella averaged 10.6 mm in the younger cohort and 13.4 mm in the older cohort with no significant difference between the two groups (Figure 1). There was no significant difference in average QTA/PL% which was found to be 47.8% and 48% for the younger and older cohorts respectively (Figure 1). PL was significantly longer in the older cohort (Figure 1). As shown in Figure 2, the insertion of the proximal MPFC into the quadriceps tendon can be variable across specimens.Conclusion:This study clarifies the anatomy of the pediatric MPFC in exceptionally rare pediatric specimens. The MQTFL relationship to the quadriceps tendon is important to guide surgical reconstructions of the medial stabilizers of the patellofemoral joint. Primary and recurrent patella instability remains a significant problem in those under 20 years. A better understanding of the MPFC (both the MQTFL and MPFL components) will support anatomic reconstructions to stabilize the joint.Figure 1:QTA, PL, and QTA/PL% for individual specimens.Figure 2:MPFC Insertion into the Quadriceps Tendon.

Lateral Harvest of an Osseous-Based Quadriceps Tendon Autograft Results in Thinner Remaining Patellar Bone.

Background:Patellar fracture after quadriceps tendon (QT) autograft harvest for anterior cruciate ligament reconstruction (ACLR) has been reported in up to 8.8% of patients.Purpose:To determine the thickness of the remaining patellar bone across the QT graft harvest location while providing clinical guidance for safely harvesting a patellar bone block when using a QT graft in ACLR.Study Design:Descriptive laboratory study.Methods:Medial and lateral QT graft boundaries were marked using a bone saw on 13 cadaveric patellae, and 3-dimensional computed tomography models were created. After the harvest of a virtual bone block with a maximum depth of 10 mm, the thickness of the remaining bone was measured across the graft harvest location in 9 zones. The thickness of the remaining bone was analyzed according to zone, graft harvest location, and patellar facet length. Risk zones were defined as <50% total patellar depth remaining.Results:We observed substantial variability in QT bone block harvest location, in which the distance between the lateral boundary of the harvest location and the lateral patellar cortex was from 21.2% to 49.2% of the axial patellar width. There was significantly less bone remaining in the lateral columns (mean ± SD, 7.56 ± 2.19 mm) compared with the medial columns (9.83 ± 2.10 mm) of the graft harvest location (P = .028). The number of risk zones was significantly associated with distance to the lateral cortical edge, with an increase in 0.59 zones with every 1-mm decrease in distance to the lateral cortex edge (b = -0.585; R 2 = 0.620; P = .001). With every 1-mm increase in the distance of the lateral cortex to the lateral graft boundary, the thickness of bone remaining in the lateral column increased by 0.412 mm (P < .001). No risk zones were encountered when the lateral boundary of the harvest location was created 18.9 mm from the lateral edge of the patella or 43% of the total patellar width from the lateral edge.Conclusion:Harvest of a more laterally based QT autograft bone block resulted in thinner remaining patellar thickness, increasing the potential of encountering a risk zone for fracture.Clinical Relevance:Care should be taken to avoid harvesting the patellar bone block too laterally during ACLR.

Characteristics of the patellofemoral joint of patients with DDH and the effects of Bernese periacetabular osteotomy on the patellofemoral joint

BackgroundSome patients with developmental dysplasia of the hip (DDH) complained of anterior knee pain (AKP) before and after Bernese periacetabular osteotomy (PAO) surgery. The purpose of this study was to (1) identify the characteristics of patellofemoral joint (PFJ) deformities in patients with DDH and (2) to determine the effects of PAO on the PFJ.MethodsSeventy patients (86 hips) were included in the DDH group. Thirty-three patients (33 knees) without AKP and hip pain were included in the control group. All patients underwent simultaneous CT scans of the hip and knee joints before PAO and after hardware removal surgery. The distance from the anterior inferior iliac spine to the ilioischial line (DAI), was measured in DDH patients. Imaging parameters of knees, including the sulcus angle (SA), femoral trochlear depth (FTD), patellar width (PW), tibial tuberosity-trochlear groove (TT-TG), patellar tilt angle (PTA) and lateral shift of the patella (LSP) were measured in patients in both the DDH and control group. TT-TG, PTA, and LSP of DDH patients were measured before PAO and after hardware removal. The DAI, PTA, LSP and TT-TG of all DDH patients before and after Bernese PAO were compared using paired t-tests. The FTD, PW, and SA of the DDH patients and the control group were analyzed using independent t-tests. PTA, TT-TG, and LSP between the control group and preoperative DDH patients, between the control group and post PAO patients were compared using independent t-tests.ResultsThe DAI changed from 4.04 ± 0.61 mm before PAO surgery to 5.44 ± 0.63 mm after PAO surgery. The SA of the DDH group (140.69 ± 11.30 degree) was greater than that of the control group (130.82 ± 6.43 degree). The FTD and the PW of the DDH group (5.45 ± 1.59 mm, 4.16 ± 0.36 mm) were smaller than that of the control group (7.39 ± 1.20 mm, 4.24 ± 0.38 mm). The changes in LSP, PTA, and TT-TG before and after surgery were not statistically significant. Both before and after PAO, there was no statistically significant difference in the parameters of LSP, PTA, and TT-TG compared with the control group.ConclusionThe knee joints of DDH patients presented a certain degree of femur trochlear groove dysplasia and patellofemoral instability. PAO surgery did not change PFJ stability, although the origination point of the rectus femoris muscle moved laterally during PAO surgery.

Morphometric analysis of the Filipino knee and its implication in total knee arthroplasty prosthesis design

BackgroundProsthesis factors account for a quarter of the dissatisfaction rates among post-total knee replacement (TKR) patients. In the Philippines, the available prostheses have pre-determined sizes and dimensions that are based on Caucasian morphometric data. This can pose a problem, since according to previous studies Asian knees have smaller dimensions compared to Caucasians. Since there is a paucity of research looking into the fitness of these prostheses to the Filipino knee, this study was pursued.MethodsThis study measured 675 knees of 675 adult Filipinos from January 2018 to December 2020. The morphometric measurements were performed on T1-weighted magnetic resonance images. The distal femoral morphometry included: the anteroposterior distance, lateral and medial anteroposterior distances, mediolateral distance, anterior and posterior mediolateral distances, and the femoral aspect ratio. The proximal tibial morphometry included: the anteroposterior distance, mediolateral distance, the medial and lateral anteroposterior distances, and the tibial aspect ratio. The patellar height, width, and thickness were also determined. Statistical analyses were done by using SPSS (version 26) and Microsoft Excel (version 2016).ResultsThe mean femoral medial and lateral anteroposterior distances were 57.6 mm and 57.1 mm, respectively. The femoral mediolateral distance was 69.3 mm, and the mean femoral aspect ratio was 1.21. The mean proximal tibial antero-posterior and mediolateral distances were 45.3 mm and 71.9 mm, respectively. The mean tibial aspect ratio was 1.66. Most TKR prostheses can be fitted to the Filipino knee but underhang on the mediolateral aspect is commonly observed in both the femoral and tibial components. The mean patellar height and width of Filipinos were 39.6 mm and 42.6 mm, respectively while the average thickness was 23.1 mm.ConclusionMost prostheses available in the Philippine and Asian markets can be fitted into Filipino knees albeit the underhang observed in the mediolateral aspects of both femoral and tibial components. Potential patellar complications are unlikely given the adequate thickness. To avoid the potential mismatch, the best approach is to design a prosthesis aptly suited for the Filipino knees.

Morphometry of the pedipalp patella provides new characters for species-level taxonomy in whip spiders (Arachnida, Amblypygi): A test case with description of a new species of Phrynus

Whip spiders (Amblypygi Thorell, 1883) are easily distinguished from their spider relatives (Araneae Clerck, 1757) by their raptorial pedipalps, the second pair of appendages, which are covered in spines and used to grasp and impale prey. Among other characters, the number, distribution, and size differences among the pedipalp spines continue to be important for whip spider systematics at different levels in the taxonomic hierarchy. However, traditional meristic and qualitative characters used to describe the pedipalp spines often limit their use for species-level taxonomy, as character states are invariant or overlapping. The present study employs landmark-based morphometrics to map the morphospace comprising the retrolateral surface of the pedipalp patella and its dorsal spines in a group of Neotropical whip spiders of the genus Phrynus Lamarck, 1801, all of which share an inconspicuous spine on the prodorsal surface of the pedipalp tarsus, i.e., "group B" proposed by Quintero (1983). The analysis presented demonstrates that the relative pedipalp patella lengths and the patella spine P3 length to patella width ratios are of similar use for species diagnosis as the commonly employed relative length of leg femur I. Importantly, the analysis reveals that, beyond the traditional approach of qualitatively reporting relative pedipalp patella dorsal spine lengths (e.g., P3 > P5 > P2 > P4 > P6 > P1), the ratios between spine lengths are useful morphometric characters for species-level taxonomy in Phrynus. New morphometric ratios are provided for the species of Phrynus group B and used, together with traditional characters, to describe Phrynus guarionexi sp. nov. from the Dominican Republic. Finally, new morphological data are provided concerning the cerotegument, frontal process and prolateral surface of the pedipalp tibia in the species of group B.

The relationship between patellar volume and trochlear volume in patients with patellofemoral instability

To investigate a possible relationship between both the volume and morphology of the patella and the volume of the trochlea in trochlear dysplasia (TD). Eighteen patients with TD and 18 controls were evaluated retrospectively in two groups using computed tomography (CT). Patellar morphology was evaluated with the standard measurement methods described in the literature. Additionally trochlear sulcus volume (TV) and patellar volume (PV) were measured quantitatively using the three-dimensional volume-rendering method. The relationship between patella dimensions and volume and trochlea volume was evaluated. The length of the medial patellar facet (lMP), patellar width (PW), TV and PV were significantly lower in the patient group. When compared according to Dejour types, PW was statistically significantly lower than the control group in those with high-grade and those with low-grade dysplasia. A positive correlation was found between the TV and PV in both groups (patient group: r=0.583 p=0.011; control group: r=0.485 p=0.042). CONCLUSİONS: PV and the TV are related. Therefore, PV can be used as a determining parameter in the evaluation of TD. This technique can also be used for prosthesis construction and more accurate surgical planning.

Morphometric Analysis of Patella and Patellar Ligament in the Cadavers of Nepalese Origin

INTRODUCTION: The patella is the largest sesamoid bone in the body which develops within the tendon of the quadriceps femoris muscle. The patellar ligament is the continuation of distal part of the quadriceps femoris which finally ranges from the tip of patella to the tibial tuberosity of the tibia. The objectives of the study was to establish the morphometry of the Patella and Patellar ligament in correlation with gender and prevalence of types of patella. MATERIALS AND METHODS: The present study was conducted at the department of Anatomy of Nobel Medical College, Biratnagar, Nepal from Jan 2018 to June 2021. Twenty-six well embalmed adult cadavers (n=52) of known sex (13 Females and 13 Males) without any gross damage to the lower limbs were considered for the study. RESULTS: Out of the 52 limbs studied, the mean value of the length of patella, width of patella, thickness of patella in male were respectively 36.23±4.20mm, 37.15±6.09mm, 17.00±1.87mm. In female the values were 33.53±4.80mm, 34.53±6.07mm, 16.00±1.95mm which are highly significantly (p&lt;0.005). In contrast it was also observed that the length of patellar ligament did not showed the significance differences between the male 45.92mm and female 44.92mm (p&gt;0.05). So from here we can conclude that the morphometry of the patella plays an important role in the gender determination. CONCLUSIONS: The obtained data will be useful for the Comparative anatomy, Anthropology, Forensic Science and Evolutionary biology, anthropological records in context of Nepal and reference for the Orthopaedic surgeons in conducting the Knee replacement surgery as well.

Tibial Tubercle–Trochlear Groove/Trochlear Width Is the Optimal Indicator for Diagnosing a Lateralized Tibial Tubercle in Recurrent Patellar Dislocation Requiring Surgical Stabilization

To identify the individualized method of quantifying lateralization of the tibial tubercle with the best diagnostic effectiveness, as evaluated by measurement repeatability using the intraclass correlation coefficient (ICC), the size of the difference between the case group and the control group, and receiver operating characteristic (ROC) curve analysis. Patients who had undergone surgery for recurrent patellar dislocation (the case group) and patients who had no history of patellar dislocation (the control group) from January 2014 to December 2019 were included in the study. Six indices that describe lateralization of the tibial tubercle were calculated using either computed tomography (CT) or magnetic resonance imaging (MRI): tibial tubercle lateralization (TTL), tibial tubercle-trochlear groove (TT-TG) ratio, tibial tubercle-posterior cruciate ligament (TT-PCL) ratio, TT-TG index, (TT-TG)/patellar width (PW), and (TT-TG)/trochlear width (TW). Diagnostic effectiveness was evaluated by 1) intra-rater reliability (measurements on two occasions) and inter-rater reliability (measurements by two assessors) using the ICC, 2) the size of the difference between the case group and the control group, and 3) ROC curve analysis, measuring the area under the ROC curve (AUC) and the post hoc power. 100 knees in 88 patients who had undergone surgery for recurrent patellar dislocation and 55 knees in 53 patients who had no history of patellar dislocation were analyzed. The ICC for all the methods were higher than .75. The mean differences between the case group and the control group for TTL, TT-TG ratio, TT-PCL ratio, TT-TG index, (TT-TG)/PW, and (TT-TG)/TW were 2%, 8%, 2%, 12%, 24% and 56%, respectively. The mean differences between the case group and the control group for (TT-TG)/TW was significantly greater than those for the other methods (P < .0001, unpaired t-test). AUC of TTL, TT-TG ratio, TT-PCL ratio, TT-TG index, (TT-TG)/PW, and (TT-TG)/TW were .708, .880, .630, .814, .882, and .905. AUC of (TT-TG)/TW was significantly greater than those of TTL and TT-PCL ratio (P < .0001). The post hoc power for TT-PCL ratio, TT-TG index, (TT-TG)/PW, TT-TG ratio, (TT-TG)/TW, and TTL were 78%, 81%, 88%, 88%, 91%, and 71%, respectively. Of the six indices evaluated in this study, (TT-TG)/TW showed the greatest mean difference between the two groups, had the greatest diagnostic utility (as measured by AUC values) and had excellent inter-rater and intra-rater reliability (as measured by ICCs). Thus, it may be the best individualized index for diagnosing a lateralized tibial tubercle in patients with recurrent patellar dislocation requiring surgical stabilization compared to patients with no history of patellar dislocation. Level III, diagnostic study, retrospective cohort study.

Evaluation of patellar dimension and Bristol Index in Asian population: An MRI study

BackgroundRestoration of patellar thickness is pivotal during a total knee arthroplasty (TKA). Several studies showed there are differences in the knee measurements between Asian and Western population. PurposeThis study aims to evaluate the patellar dimension and Bristol Index of patellar width to thickness (BIPWiT) using magnetic resonance imaging (MRI) in Asian population. Study designThis is a descriptive epidemiology study. Methods101 MRI scans of young adult patients with normal patellofemoral joint (PFJ) age 17–40 were evaluated from January 2019 to December 2020. Exclusion criteria included patella-femoral pathology and degenerative joint disease. Data of gender, body height and weight were obtained from physical examination, while patella height, width and thickness were obtained using MRI measurement. Descriptive analysis was used to get the mean and standard deviation of patella dimension, whereas correlation between patella thickness with patella width and length were analyzed using Pearson correlation and BIPWiT ratio was obtained by dividing the patellar width and patellar thickness. ResultsMean patellar length was 30.06 ± 2.94 (29.48–30.64); patellar width was 44.13 ± 4.44 (43.26–45.01); and patellar thickness was 23.89 ± 2.33 (23.43–24.35). Patellar dimension in male were significantly larger compared to female (P < 0.001). However, there was no difference in cartilage thickness between male and female (P = 0.305). There was strong correlation between patellar width and patellar thickness (r = 0.66; P < 0.001) with BIPWiT ratio of 1.85 ± 0.15. ConclusionBIPWiT of 1.8:1 between patellar width and patellar thickness was recommended as a guide for patellar thickness restoration during TKA. There is no difference of patellar dimension between Asian and Western population in a healthy knee. Clinical relevanceThe result of BIPWiT ratio found in this study may aid upon pre-operative planning prior TKA for surgeons in order to achieve optimal patellar thickness and avoid patellofemoral problem. What is known about the subjectCurrently there are raising concerns about the different sizes of knee measurements between Asian and Western population which will affect techniques during TKA to achieve optimum result. What this study adds to the existing knowledgeThis study not only prove that there is no difference between patellar dimension of Asian and Caucasian but also found a similar BIPWiT ratio for patellar resection during TKA with previous literature. Level of evidenceLevel III.