Fabella and patella variants: radiographic prevalence, distribution and clinical relevance in a population of black african descent

Common fibular nerve palsy due to the Fabella: A review

One of the most common nerve palsies - common fibular nerve palsy - can be caused by the variant small sesamoid bone in the posterolateral compartment of the knee joint known as the fabella. We compared and reviewed all reported cases of common fibular nerve palsy due to fabellae in the English literature. Compression can develop spontaneously or post-surgically (total knee arthroplasty). Symptoms progress rapidly to complete foot drop. Among all the cases reviewed, 68.42% were males with a median age of 39.39 years. Fabella compression was more common in the left common fibular nerve (CFN) (63.16%). Both big (23 × 20 × 16 mm) and small (5 × 5 mm) fabellae can be responsible for compression. While diagnosis can be problematic, the treatment (either surgical fabellectomy or conservative) is relatively easy and brings quick improvement.

Multipartite patella: A review of diagnostic techniques and management of the symptomatic patient

Multipartite patella is an anatomical variant classified by the fragmentation of the main patellar body. The cause of this variant is due to failure in fusion of the patellar ossification centers. It is commonly misdiagnosed as a fracture of the patella in clinical practice, leading to unnecessary treatment measures. The aim of this review is to provide an overview of the development and classification of this variation, diagnostic imaging techniques, and assess the optimal management technique for the symptomatic patient. Multiple radiographic methods are used to identify this variant, with recent studies highlighting high sensitivity rates for nonradiative methods (ultrasound). In terms of symptomatic management, accessory fragment excision and vastus lateralis release provide the greatest alleviation of symptoms, with screw fixation being less favorable.

The Effect of Patellofemoral Maltracking and Patella Type on Symptomatic Bipartite Patella

Purpose The aim of this study is to investigate the relationship of trochlear dysplasia (TD) and patella type with bipartite patella (BP). Materials and methods A total of 5,081 knee MRIs taken in our institution were reviewed retrospectively. Patients with a history of knee surgery, previous or recent trauma, and rheumatologic involvement were excluded from the study. The MRIs of 49 patients with bipartite/multipartite patella were detected. Three patients were excluded: two patients had a tripartite variant, and one had multiple osseous dysplastic findings. Overall, 46 patients with BP were included in the study. BPs were classified as type I, II, and III. Patients were divided into symptomatic and asymptomatic groups according to the presence of edema within the bipartite fragment and adjacent patella. Patients were examined in terms of patella type, trochlear dysplasia, tuberosity-trochlear groove (TT-TG) difference, sulcus angle, and sulcus depth. Results There were 46 patients with BP (28 males and 18 females) (mean age: 33±9.5 years, range: 18-54). Thirty-eight bipartite fragments (82.6%) were type III and eight (17.4%) were type II. There was no type I BP. Seventeen (36.9%) were symptomatic, and 29 (63.1%) were asymptomatic. Seven of the type II (87.5%) and 10 of the type III (26.3%) bipartite fragments were symptomatic. The frequency and degree of trochlear dysplasia (p=0.007 and p=0.041, respectively) were found to be higher in symptomatic patients. The trochlear sulcus angle was higher (p=0.007) and the trochlear depth was lower (p=0.006) in the symptomatic group. No statistically significant difference was found (p=0.247) in terms of TT-TG difference. Type III and type IV patella were more common in the symptomatic group. Conclusion The current study shows that patellofemoral instability and patella type are associated with symptomatic BP. Patients with trochlear dysplasia, type II BP, and disproportionate patellar facet may have a significantly increased risk of symptomatic BP.

The Ethnic and Geographical Distribution of Fabella: A Systematic Review and Meta-Analysis of 34,733 Knees

Introduction: The primary studies demonstrated that fabellar prevalence (FP) varied with ethnic and geographical distribution. Osteoarthritis (OA) and age-related degeneration have a significant association with FP. The prevalence of OA worldwide was doubled with life expectancy. Increased life expectancy has increased exposure to OA and age-related degeneration which could be a possible reason for the rise of FP. The analysis was conducted to provide insight about FP in respect to geographical, ethnic, sex, and laterality distribution.

Methodology: Eighty-six studies were included which have data from 34,733 knee joints. Fifty radiological studies were consisting of 27,293 knees and 36 cadaveric studies had the data of 7,440 knees of dissected specimens, respectively. The prevalence, Odds, and rate ratios were calculated for aging, osteoarthritis, and ethnic variation. 

Results: The worldwide FP was 25% (95% CI, 0.22, 0.28). The prevalence of fabella was found to be higher in cadaveric studies (32%) than radiological studies (19%) with significant heterogeneity. The FP was 16-18% till 1950 which was doubled by 2020 (35%). The FP in OA knee was 51% which was thrice of baseline.