Vastus Lateralis Obliquus Research Articles

Resting muscle tension and trigger points in elite junior short-track athletes and healthy non-athletes: a cross-sectional examination.

Short-track speed skating (short track) is an Olympic sport characterized by a specific body position and counterclockwise movement on the track. Based on previous studies, we hypothesized that athlete body positions employed in this sport could lead to asymmetric overuse disorders of the left lower limb muscles. An increased number of latent trigger points (LTrPs) was confirmed in individual muscles of the overloaded left limb of short-track athletes. This study aimed to compare the number of LTrPs and the level of resting muscle tone between elite junior short-track athletes and healthy non-athletes. The experimental (EXP) group comprised 15 elite short-track junior athletes from the Polish national team and the control (CON) group comprised 15 healthy young volunteers. In both groups, the left leg was tested for (i) the presence of LTrPs and (ii) resting muscle tone (RMT), assessed using surface electromyography in six muscles. The EXP group showed a higher number of LTrPs in the left lower limb, compared with the CON group. The muscle that was most significantly affected in the athletes was the vastus lateralis obliquus [χ 2 (1, N = 30), p < 0.001, V Cramer = 0.71]. This muscle also differed significantly between the groups in terms of the RMT (p = 0.033, Cohen's d = 0.87). Elite short-track junior athletes presented with increased RMT and an increased number of LTrPs in the vastus lateralis oblique muscle, compared with healthy non-athletes.

The effects of lower extremity static muscle fatigue on balance components

BackgroundThe body exhibits dynamic and static movements in response to the changes in the center of gravity in some positions. Balance plays a key role in all sports branches and daily life because it can control the lowest energy consumption and muscle activation.ObjectivesThis study investigated the effects of lower extremity static muscle fatigue on static and dynamic balance components.Design/methodsThe sample consisted of 40 healthy volunteers aged 18–24 years. Participants took part in an isometric fatigue protocol for lower extremity muscles. A squat position was used for static fatigue for lower extremity muscles. Measurements were performed in a squat press for 25 s, with the knee at a 90-degree angle and a load of about 30% of the participant's weight isometrically. The protocol was repeated five times. The participant was allowed to rest for two minutes between each repetition. The muscles and their antagonists that contracted most actively during the squat press exercise were vastus lateralis obliquus, rectus femoris, tibialis anterior, biceps femoris, semi tendineus, and lateral gastrocnemius. Electromyography (EMG) measurements were conducted on these muscles bilaterally and motion analysis system was used to standardize the 90-degree angle of the knee joint.ResultsThere was a significant difference between pre-test and post-test Eyes Open (EO) static balance scores, pre- and post-exercise post-test dynamic balance scores between non-athletes and athletes, pre- and post-exercise post-test dominant leg EO, and pre-test non-dominant leg between non-athletes and athletes (p < .05). There was a significant difference in the Median Frequency (MF) (Hz) values of the dominant leg agonist rectus femoris (p < .05) and the antagonist muscle semi tendineus (p < .05) scores during isometric squat press between athletes and non-athletes.ConclusionsWe need different applications to understand the mechanisms underlying balance and discover athletes' potential. Lower extremity proprioception exercises have positive effects on static body balance parameters.

Electromyographic activity of quadriceps muscles during eccentric squat exercises: implications for exercise selection in patellar tendinopathy

ABSTRACT This study investigated the quadriceps muscle activity during eccentric squat exercises (ESE) with different decline angles and arcs of motion regarding the proper exercise selection for patellar tendinopathy management. Electromyographic activity of the rectus femoris, vastus lateralis, and vastus medialis obliquus (VMO) muscles was measured during ESE on 0°, 5°, 10°, 15°, and 20° decline in 20 recreationally active participants. The eccentric phase was divided into 0–30°, 30–60°, 60–90°, 0–60°, 30–90°, and 0–90° of knee flexion simultaneously via motion-analysis system. The analyses showed that there was a significant decline angle × arc interaction effect on electromyographic activity of all muscles during knee flexion movement. The main effect was found for the arc of motion of knee flexion, and the main effect for the decline angle also was present for each muscle, except for VMO. This study demonstrated that most selective quadriceps eccentric activation occurred during ESE performed on 20° decline throughout 60–90° of knee flexion.

Association Between Hip Rotation and Activation of the Quadriceps and Gluteus Maximus in Male Runners.

Background:Although running can provide health benefits, knee joint injuries are frequently reported by recreational runners. To date, the precise mechanism responsible for anterior knee pain remains elusive, and the source of symptoms is debated. Inconsistencies are found in the literature pertaining to the relationship between hip mechanics and activity in the quadriceps and gluteus maximus (GMax) during the running gait.Purpose/Hypothesis:To investigate the correlations between hip rotation and the activity in the quadriceps and GMax during running. We hypothesized that increased hip rotation is correlated with decreased activity in these muscles.Study Design:Descriptive laboratory study.Methods:A cohort of 30 healthy recreational runners volunteered to participate in the study (mean ± SD age, 28.8 ± 5.66 years; height, 1.73 ± 0.05 m; mass, 69 ± 6.3 kg; body mass index, 23.02 ± 1.42 kg/m2). Surface electromyography (EMG) data were obtained from the GMax, vastus medialis obliquus (VMO), and vastus lateralis obliquus (VLO). These data were synchronized with a motion capture system during a level-surface running activity at a speed of 3.2 m/s.Results:A significantly strong, negative correlation was found between the hip internal rotation angle and EMG activity of the GMax and the VMO. However, the VLO showed a significant, moderate, and positive correlation of activity with the hip internal rotation angle.Conclusion:The present study showed that during level-surface running, decreased GMax activity may be the cause of distal joint injuries and alteration in quadriceps muscle activity.Clinical Relevance:Because GMax activity is important for controlling the lower body mechanics during running, evaluating GMax activity and internal hip rotation angle is important to prevent the running-related knee injuries that are linked to quadriceps deficits, such as patellofemoral pain. Additionally, clinicians and trainers should consider strengthening the GMax while rehabilitating running-related knee injuries.

Quadriceps Muscle Mechanical Simulator for Training of Vastus Medialis Obliquus and Vastus Lateralis Obliquus Mechanical Properties

Objectives:In classical anatomy quadriceps muscle has four heads. Clinical studies have demostrated 6 heads of this muscle. These heads were demostrated seperately not only by their functional properties,but also by innervation and kinesiological properties. In our previous study we have developed and demostrated electrophysiological properties of vastus medialis obliquus by an electronic patient simulator. The purpose of this study is to develop a mechanical simulator which can be used to demostrate mechanical properties of 6 heads of quadriceps muscle and the screw home mechanism.Methods:Quadriceps femoris muscle has 6 heads: rectus femoris, vastus intermedius, vastus medialis obliquus, vastus medialis longus, vastus lateralis obliquus and vastus lateralis longus. The fundamental mechanical properties of each head is seperated by insersio and angle of pull. Main design principle was to demostrate all heads with insersio and angle of pull properties. Second design principle was to demostrate the screw-home mechanism which is the result of difference in articular surfaces of medial and lateral of condyles of femur.Results:Final design of the simulator consists of three planes for demostration of angle of pull and pulling forces (patellar plane, proximal and distal planes) of each heads. On each plane channels were graved as origo and insersio for demostration of angle of pull. Distal plane was movable for demostration of pulling forces in different angels of knee flexion and extention. Also proximal plane was adjustable to demostrate different sitting and standing positions. Srew home mechanism was demostrated by specially designed hingle mechanism. Left and right side hingle mechanisms have different radii as femoral condyles and this difference can cause rotation in terminal extension as in the screw home mechanism.Conclusion:Vastus medialis obliquus, vastus lateralis obliquus and screw-home mechanism have clinical significance. We were not able to find any study which deals with training of screw home mechanism and vastus medialis obliqus and wastus lateralis obliquus muscles in the literature. The purpose of this study was to develop a simulator which can demostrate mechanical properties of vastus medialis obliquus and vastus lateralis muscles and screw home mechanism. As a result a traning simulator with stated properties was developed. In this simulator force measurement is acheived with analog dynamometers and future studies may focus on improvement of this simulator with digital force measurement.

Shear Wave Elastography Properties of Vastus Lateralis and Vastus Medialis Obliquus Muscles in Normal Subjects and Female Patients With Patellofemoral Pain Syndrome

Shear Wave Elastography Properties of Vastus Lateralis and Vastus Medialis Obliquus Muscles in Normal Subjects and Female Patients With Patellofemoral Pain Syndrome

Ativação muscular estabilizadora da patela e do quadril durante exercícios de agachamento em indivíduos saudáveis

Hip and knee muscle weaknesses have been associated with the onset of anterior knee pain (AKP). Therefore, the understanding of how squats exercises can be performed in order to optimize the electrical activity of these muscles is relevant for physical therapy treatments. To compare the electromyographic activity of patella and pelvic stabilizers during traditional squat and squat associated with isometric hip adduction or abduction in subjects without AKP. Electromyography signals were captured using double-differential electrodes at the vastus medialis obliquus (VMO), vastus lateralis obliquus (VLO), vastus lateralis longus (VLL) and gluteus medium (GMed) in 15 healthy and sedentary women during squats exercises: traditional and associated with hip adduction and hip abduction with load of 25% of body weight. Linear mixed models with significance level of 5% were used for data analysis. Squat associated with hip adduction and abduction produced electromyographic activity of GMed of 0.47 (0.2) and 0.59 (0.22) respectively, while conventional squat produced an electromyiographic activity of 0.33 (0.27). The higher VMO activity was 0.59 (0.27) during the isometric contraction in the squat associated with hip adduction. The higher VLO activity was 0.60 (0.32) during isometric contraction in the squat associated with hip abduction. Squat exercise associated with hip adduction increased VMO muscle activity as well as the activity of GMed activity.

Clinical and radiographic outcomes of minimally invasive total knee arthroplasty through a lateral approach

With increasing confidence and surgical experience, minimally invasive surgery (MIS) in total knee arthroplasty (TKA) is now being applied to more complicated cases. The present study assessed the feasibility of MIS-TKA using a lateral approach for valgus knees. Subjects comprised 26 patients with valgus knees who underwent MIS-TKA using a lateral subvastus approach. Five cases required a 1-cm snip of vastus lateralis obliquus, to shift the patella medially without eversion. Clinical scores and radiographic parameters of lateral MIS-TKA were examined and compared with those of 26 medial MIS-TKAs matched for preoperative patient characteristics. The lateral MIS-TKA group showed slightly longer operative time and larger skin incision than the medial MIS-TKA group. Nevertheless, myoglobin index and pain on a visual analog scale on postoperative day 7 were significantly lower in the lateral MIS-TKA group than in the medial MIS-TKA group. Postoperative improvement of clinical scores was quite comparable between lateral and medial MIS-TKA groups. Radiographic assessment revealed that tibiofemoral mechanical axis aligned within ±3° from ideal in 24 of 26 patients after lateral MIS-TKA. MIS technique-related complications occurred in only 1 patient presenting with subsidence of the tibial component, due to malpositioning of the tibial component. From the perspectives of postoperative pain, clinical scores, radiographic accuracy, and postoperative complication rate, lateral MIS-TKA achieved comparable or superior results to medial MIS-TKA. This technique may offer a promising technical option that can be utilized for most patients with valgus knee deformity.

Avaliação eletromiográfica e ressonância magnética do joelho de indivíduos com síndrome da dor femoropatelar

To analyze the electrical activity of the vastus medialis obliquus (VMO), vastus lateralis longus (VLL) and vastus lateralis obliquus (VLO) muscles of individuals with patellofemoral pain syndrome (PFPS) during maximum voluntary isometric contraction (MVIC) of lower leg extension with the knee at 30 degrees; to assess pain using a visual analogue scale (VAS); and to assess patellar positioning using magnetic resonance imaging (MRI). Twelve women with PFPS and 12 clinically normal women were evaluated. They performed five MVICs of lower leg extension at 30 degrees for electromyographic (EMG) analysis. Using MRI, the sulcus angle (SA), congruence angle (CA), patellar tilt angle (PTA) and patellar displacement (PD) were obtained. The following statistical tests were used: analysis of variance (ANOVA) for repeated measurements to assess EMGs; Mann-Whitney U test to analyze MRIs; Pearson's (r) correlation test between EMGs and MRIs; and one-way ANOVA to evaluate pain (p < or = 0.05). In the PFPS group, there was greater electrical activity in the VLL than in the VMO. In both groups, there was greater electrical activity in the VMO and VLL than in the VLO. In the PFPS group, the MRI showed higher SA and lower CA values, and there was a negative correlation between the VMO and the PTA. The data suggest that, in individuals with PFPS, greater electrical activity in the VLL combined with an increased SA and a decreased CA may contribute to patellar instability.

Início da atividade elétrica dos músculos estabilizadores da patela em indivíduos com SDPF

OBJETIVO: Avaliar a porcentagem de disparo inicial (PDI) dos músculos estabilizadores da patela durante exercícios de contração isométrica voluntária máxima (CIVM) em indivíduos com e sem sinais da síndrome da dor patelofemural (SDPF) nos exercícios de cadeia cinética aberta (CCA) e fechada (CCF). MÉTODO: Foram avaliadas 10 mulheres sem queixa de dor anterior no joelho e 12 mulheres com sinais de SDPF durante a CIM em CCA e CCF com o joelho posicionado a 90º de flexão do joelho. O início da atividade eletromiográfica dos músculos vasto medial obliquo (VMO), vasto lateral obliquo (VLO) e vasto lateral longo (VLL) foi identificada por meio de um algoritmo no programa Myosystem Br 1. A análise estatística empregada foi o teste Qui-Quadrado e o teste t de student, ambos os teste com nível de significância de 5%. RESULTADOS: Os músculos VMO e VLO apresentaram uma maior PDI em relação ao músculo VLL durante os exercícios em CCA para ambos os grupo e para o grupo SDPF em CCF. Não foi observado diferença entre os grupos. CONCLUSÃO: Pode-se sugerir que tanto os exercícios em CCA quanto em CCF, parecem beneficiar o sincronismo na musculatura estabilizadora da patela, podendo ser indicado nos programas de tratamento fisioterapêutico.

Atividade eletromiográfica do vasto medial oblíquo e vasto lateral durante atividades funcionais em sujeitos com síndrome da dor patelofemural

OBJECTIVE: The purpose of this study was to evaluate the amplitude and onset of electrical activation of the vastus medialis obliquus (VMO), vastus lateralis longus (VLL) and vastus lateralis obliquus (VLO) during functional activities in individuals with patellofemoral pain syndrome (PFPS). METHODS: Twenty women participated in the study: ten in a control group and ten in the group with PFPS. The electromyographic signal of the quadriceps muscle was detected using simple active differential surface electrodes and a four-channel electromyography system, during open kinetic chain activities (using an isokinetic dynamometer) and closed kinetic chain activities (step and squat maneuvers). For the statistical analysis, Student's t test and ANOVA with Tukey's post-hoc method were used, with a significance level of p<0.05. RESULTS: The results suggested that the electrical activation of the VMO was less intense than in the VLO (p=0.04) and that there was greater delay in VMO onset (p=0.0023) in the group with PFPS, with regard to all of the functional activities evaluated. There was a significant difference between the VMO and VLO in relation to the activities of isokinetic extension at 30o/s (p=0.042) and step down with knee flexion at 75o (p=0.038) in the group with SDPF, and in the activities of rising from a bench (p=0.041), single-leg hop (p=0.046) and heel raising (p=0.004) in the control group. CONCLUSIONS: Under the experimental conditions used, this study suggests that there is an imbalance in the electric activity and abnormal recruitment patterns among the VMO, VLL and VLO muscles in individuals with PFPS, with greater delay and lower amplitude of activation of the VMO in this group.

Anatomy of the lateral retinaculum of the knee

Anatomical descriptions of the lateral retinaculum have been published, but the attachments, name or even existence of its tissue bands and layers are ill-defined. We have examined 35 specimens of the knee. The deep fascia is the most superficial layer and the joint capsule is the deepest. The intermediate layer is the most substantial and consists of derivatives of the iliotibial band and the quadriceps aponeurosis. The longitudinal fibres of the iliotibial band merge with those of the quadriceps aponeurosis adjacent to the patella. These longitudinal fibres are reinforced by superficial arciform fibres and on the deep aspect by transverse fibres of the iliotibial band. The latter are dense and provide attachment of the iliotibial band to the patella and the tendon of vastus lateralis obliquus. Our study identifies two important new findings which are a constant connection of the deep fascia to the quadriceps tendon superior and lateral to the patella, and, a connection of the deeper transverse fibres to the tendon of vastus lateralis obliquus.

Análise do tempo de resposta reflexa dos músculos estabilizadores patelares em indivíduos com síndrome da dor patelofemural

OBJECTIVE: To investigate the reflex response time (RRT) of the vastus medialis obliquus (VMO), vastus lateralis obliquus (VLO) and vastus lateralis longus (VLL) muscles in clinically healthy individuals and subjects with patellofemoral pain syndrome (PPS). METHODS: Twelve clinically health women and twelve women with PPS were evaluated. Electromyography (EMG) records were obtained using active electrodes connected to an electromyograph that was activated by an external sensor attached to the medial portion of the patella ligament, by means of percussion. The RRT was analyzed by measuring the time, in seconds, between zero and peak electrical response of the VMO, VLO and VLL muscles, for both groups. The statistical analysis consisted of analysis of variance (ANOVA, p< 0.05) and the Tukey post-hoc test (p< 0.05) to compare the response between muscles, and Student's t test (p< 0.05) to compare the response between groups. RESULTS: Both groups presented lower RRT for the VMO muscle than for the VLO and VLL muscles. However, no significant difference was seen between the VLO and VLL muscles. There was no significant difference in RRT between the groups. CONCLUSIONS: According to these results, it can be suggested that the RRTs in the different portions of the quadriceps muscle do not distinguish between subjects with PPS and clinically healthy individuals. The RRT for the VMO muscle was lower than the RRT for the VLO and VLL muscles, for both groups.

The effect of hip abduction on the EMG activity of vastus medialis obliquus, vastus lateralis longus and vastus lateralis obliquus in healthy subjects

Study designControlled laboratory study.ObjectivesThe purposes of this paper were to investigate (d) whether vastus medialis obliquus (VMO), vastus lateralis longus (VLL) and vastus lateralis obliquus (VLO) EMG activity can be influenced by hip abduction performed by healthy subjects.BackgroundSome clinicians contraindicate hip abduction for patellofemoral patients (with) based on the premise that hip abduction could facilitate the VLL muscle activation leading to a VLL and VMO imbalanceMethods and measuresTwenty-one clinically healthy subjects were involved in the study, 10 women and 11 men (aged X = 23.3 ± 2.9). The EMG signals were collected using a computerized EMG VIKING II, with 8 channels and three pairs of surface electrodes. EMG activity was obtained from MVIC knee extension at 90° of flexion in a seated position and MVIC hip abduction at 0° and 30° with patients in side-lying position with the knee in full extension. The data were normalized in the MVIC knee extension at 50° of flexion in a seated position, and were submitted to ANOVA test with subsequent application of the Bonferroni multiple comparisons analysis test. The level of significance was defined as p ≤ 0.05.ResultsThe VLO muscle demonstrated a similar pattern to the VMO muscle showing higher EMG activity in MVIC knee extension at 90° of flexion compared with MVIC hip abduction at 0° and 30° of abduction for male (p < 0.0007) and MVIC hip abduction at 0° of abduction for female subjects (p < 0.02196). There were no statistically significant differences in the VLL EMG activity among the three sets of exercises tested.ConclusionThe results showed that no selective EMG activation was observed when comparison was made between the VMO, VLL and VLO muscles while performing MVIC hip abduction at 0° and 30° of abduction and MVIC knee extension at 90° of flexion in both male and female subjects. Our findings demonstrate that hip abduction do not facilitated VLL and VLO activity in relation to the VMO, however, this study included only healthy subjects performing maximum voluntary isometric contraction contractions, therefore much remains to be discovered by future research

Efeito da rotação do quadril na síndrome da dor femoropatelar

Objective: The purpose of this study was to evaluate the effect of hip rotation on the electrical activity of the Vastus Medialis Obliquus (VMO), Vastus Lateralis Obliquus (VLO) and Vastus Lateralis Longus (VLL) muscles when squatting with 45o knee flexion, in association with the neutral position, 45o lateral rotation and 15 and 30o medial hip rotation. Method: 27 women were evaluated: 15 healthy women as a control group (21.1 ± 2.1 years) and 12 subjects with patellofemoral pain syndrome (PFPS) (21.0 ± 2.3 years). The electrical activity of the quadriceps muscle was detected using simple active differential surface electrodes, an eight-channel electromyography system and the Aqdados 7.2.6 software. The data were normalized by the mean squatting percentage at 75o with the hip in the neutral position RMS (µV). Two-way ANOVA with repeated measurements followed by the Tukey post hoc test (p<0.05) was used for statistical analysis. Results: The results revealed interaction between groups and muscles (p=0.00), independent of hip position (p=0.39), and there was no interaction between groups and hip positions (p=0.96). The VMO and VLL muscles of the PFPS group showed significantly greater electrical activity than did VMO (p=0.00) and VLL (p=0.04) muscles from the control group. On the other hand, the electrical activity of the VLO muscle did not present any significant difference between the groups (p=0.99). Conclusion: Under the experimental conditions utilized, the results suggested that hip rotation did not alter the electrical activity of the quadriceps portions in either group when squatting with 45o knee flexion.

Anterior knee pain in adolescents and young adults.

The problem of anterior knee pain continues to challenge serious students of the knee. Precise measurement techniques for each component of the soft-tissue envelope about the patella remain unknown. The biomechanical contributions of the medialis, the lateral retinaculum, the vastus lateralis obliquus, the iliotibial band, and the quadriceps during strenuous activity have yet to be measured. It is difficult to design studies of knee pain because of the diverse skeletal configurations of patellofemoral joints, unknown degrees of soft-tissue laxity, variations in the alignment of the knee, and other factors. As a result, indications for surgery, and nonoperative treatment, as well as effectiveness of rehabilitation modalities, continue to be debated. Terms used to describe the anterior patellofemoral spectrum vary, making uniform classification difficult.

Insertion orientation of terminal vastus lateralis obliquus and vastus medialis obliquus muscle fibers in human knees

AbstractThe quadriceps mechanism consists of the patellar ligament distally and the quadriceps tendon proximally. The quadriceps tendon is the confluence of the tendinous portions of the vastus medialis, vastus lateralis, vastus intermedius, and rectus femoris. Lieb and Perry (J. Bone Joint Surg. 50A:1535–1547, 1968) have described the vastus medialis obliquus (VMO) and Hallisey et al. (J. Bone Joint Surg. 69A:545–549, 1987) have described the vastus lateralis obliquus (VLO). These muscles are the terminal medial and lateral insertions of the vastus medialis and vastus lateralis. This study delineates and quantifies anatomic sex differences for the medial and lateral angular terminal insertions of the vastus lateralis obliquus and vastus medialis obliquus in relationship to the longitudinal axis of the patella in 40 embalmed cadaver knees. A mathematical model is developed and discussed using least steps regression equations y = Ax + B, where y = the VLO insertion angle, x = the VMO insertion angle, A = the coefficients, and B = the y intercept. These equations are different in males and females, with males having more horizontally oriented VLO fibers than females. The vastus lateralis obliquus (VLO) insertion angle can be predicted based upon measurement of the vastus medialis obliquus insertion angle and sex: Log VLO = 1.36 + .00531 VNIO − 0.000166 (S × VMO), where S = 1 for females and S = 0 for males. In embalmed cadaver knees, the angular terminal insertion of the vastus lateralis obliquus related to the longitudinal axis of the patella is more horizontally oriented in males than in females. The angular terminal insertion of the vastus medialis obliquus of males and females does not increase equally with increases in the angular terminal insertion of the vastus lateralis obliquus. © 1993 Wiley‐Liss, Inc.

The extensor apparatus of the knee joint and its peripheral vasti: anatomic investigation and clinical relevance

Anatomic dissections of the vastus medialis m. in 115 fixed thigh specimens always demonstrated a clear separation between a long head of the muscle (VML) inserted at the base of the patella and a short head (VMO) inserted at its medial margin. The plane of separation was identified by a branch of the femoral n. in every case. In 17 instances, the localization of the nerve was superficial; in 57, it was in the areolar fascial plane; and in 41 instances in lay deeply between the muscles. The ramification of the branch of the femoral n. traversing the plane of separation showed 4 types of variation. Dissections of the vastus lateralis m. in 42 specimens always demonstrated a separation into 2 heads: a long head inserted at the base of the patella (VLL) and a short head inserted at its lateral margin (VLO). The directions of the individual heads of the quadriceps femoris m. were angulated in relation to the long axis of the femur. The deviations were between 10 degrees and 17 +/- 8 laterally for the vastus lateralis longus m. (VLL), between 26 degrees and 41 degrees laterally for the vastus lateralis obliquus m. (VLO), between 15 degrees and 18 degrees medially for the vastus medialis longus m. (VML), and between 46 degrees and 52 degrees medially for the vastus medialis obliquus m. (VMO). The results demonstrate great variation in the distal parts of the medial and lateral anterior thigh m.

Lateral Facet Syndrome of the Patella

Thirty-eight knees in 34 patients with an average age of 22 years were diagnosed as having lateral facet syndrome (LFS), a painful compressive arthropathy of the lateral facet of the patella. This diagnosis was based on the physical findings of tenderness at the lateral patellofemoral joint line, tenderness over the vastus lateralis obliquus (VLO) tendon just above the patella, a positive medial apprehension test, and marked resistance to medial patellar displacement with the knee flexed 30 degrees. The most common complaints were patellar pain with activity, pain with prolonged knee flexion, intermittent knee swelling, and giving way. At surgery, the VLO, the lateral retinaculum (LR), and the anterior fibers of the iliotibial tract (ITT) were sequentially divided from the lateral border of the patella. Each was temporarily reattached to a cuff of soft tissue left on the patella using surgical clamps to determine its contribution to lateral restraint. The VLO was found to be the primary restraint in one-half of the knees. In one-third of the knees, all three of the structures contributed equally. In six knees, the primary restraint was the anterior fibers of the ITT, whereas the LR was the primary restraint in only two. The distal ends of these three structures were then resected to prevent rescarring and retethering. At a minimum follow-up period of two years, 87% had satisfactory relief of their patellar pain, had returned to normal activities, and had no or minimal physical findings of LFS. The procedure is recommended for patients who have failed other procedures and in those whose symptoms cannot be controlled by activity modification, exercises, bracing, or medication.

Anatomy of the junction of the vastus lateralis tendon and the patella.

Forty-one knees from adult cadavera (twenty female and twenty-one male) were dissected to study the relationship between the longitudinal axis of the patella and the angles of insertion into it of the vastus lateralis and vastus lateralis obliquus muscles. The mean and variance in the angles of insertion of the vastus lateralis obliquus tendon were found to be significantly different between men and women (p less than 0.05 and p less than 0.01, respectively). Three distinct anatomical patterns in the insertion of the vastus lateralis obliquus muscle were delineated. The vastus lateralis muscle, particularly the vastus lateralis obliquus, creates an important lateral force-vector on the patella.