gms | German Medical Science

Objective: A lack of standardization and agreement toward the approach of patellofemoral assessment and interventions lead to a plethora of unsubstantiated outcomes. It was hypothesized that the anatomical location of the vastus medialis oblique plays a determinant role. Thus, the objective of this study was to identify the anatomical location of the vastus medialis muscle insertion into the patella.

Material/Methods: Fourteen (14) cadavers were measured (28 knees total) for accessibility of the Vastus Medialis Obliquuis (VMO)Muscle insertion. Subjects were of equal gender comprising 7 each. Most cadavers required cutting of fascia, adipose, and other tissues for identifying purposes of the actual attachment site. Two independent investigators were trained to take measurements from the apex of the patella to the most distal VMO fibers (cm) at a perpendicular intersection. The Intra-rater reliability ICC = .79 (>.75=good) was established.

Results: Descriptive statistics were used to compare the attachment sites amongst cadaveric specimens. Variations of up to 5mm for both male and female cadavers were noted related to the overall distal length (Average right male VMO: 18.3 mm, average left male VMO: 18.9 mm; Average right female VMO: 18.4 mm, Average left female VMO: 17.3 mm. The VMO to the patella ration was also measured with only smaller differences in variation (Male VMO to patella ratio: Right 0.34:1 mm, Left 0.38:1 mm; Female VMO to patella ratio: Right 0.37:1 mm, Left 0.35:1 mm.

Conclusion: Successful rehabilitation for patellofemoral conditions has been reported as a quandary by sports medicine practitioners. One multi-factorial dilemma often discussed contributing to the challenge of decreasing a person’s knee pain is the VMO muscle attachment site, firing pattern, and frequent atrophy. The purpose of this study was to assess any varying muscle attachment patterns as a possible explanation of rehabilitation success versus failure. Our findings indicate that there are no clear differences between males and females, or left versus right, on average, for the VMO insertion. Limitations of this study include the age of the cadavers, the difficulty in identifying the exact location of the fiber insertion, and the overall condition of the cadavers versus actual in vivo tissue measurements. Future studies of this are encouraged to determine if there are clinical implications related to the vasti attachment that may be able to predict successful outcomes.