Anterior knee pain, also commonly known as patellofemoral pain syndrome (PFPS) is a frequently encountered musculoskeletal disorder and one of the most prevalent causes of knee pain diagnosed by sports medicine physicians. 1 It is estimated that anterior knee pain accounts for 25% of all knee
Rumit S. Kakar, Hilary B. Greenberger and Patrick O. McKeon
Lílian Ramiro Felicio, Marcelo Camargo Saad, Rogério Ferreira Liporaci, Augusto do Prado Baffa, Antônio Carlos dos Santos and Débora Bevilaqua-Grossi
The purpose of this study was to correlate the trochlear shape and patellar tilt angle and lateral patellar displacement at rest and maximal voluntary isometric contraction (MVIC) exercises during open (OKC) and closed kinetic chain (CKC) in subjects with and without anterior knee pain. Subjects were all women, 20 who were clinically healthy and 19 diagnosed with anterior knee pain. All subjects were evaluated and subjected to magnetic resonance exams during OKC and CKC exercise with the knee placed at 15, 30, and 45 degrees of flexion. The parameters evaluated were sulcus angle, patellar tilt angle and patellar displacement using bisect offset. Pearson’s r coefficient was used, with p < .05. Our results revealed in knee pain group during CKC and OKC at 15 degrees that the increase in the sulcus angle is associated with a tilt increase and patellar lateral displacement. Comparing sulcus angle, patellar tilt angle and bisect offset values between MVIC in OKC and CKC in the knee pain group, it was observed that patellar tilt angle increased in OKC only with the knee flexed at 30 degrees. Based on our results, we conclude that reduced trochlear depth is correlated with increased lateral patellar tilt and displacement during OKC and CKC at 15 degrees of flexion in people with anterior knee pain. By contrast, 30 degrees of knee flexion in CKC is more recommended in rehabilitation protocols because the patella was more stable than in other positions.
Dominique C. Leibbrandt and Quinette A. Louw
Anterior knee pain (AKP) affects up to half of young sports participants. 1 The condition impairs functional ability and is persistent. These symptoms hinder activities of daily living and sports participation. 2 Almost all individuals (91%) of patients diagnosed with AKP continue to experience
Diane C. Westfall and Teddy W. Worrell
Anterior knee pain syndrome (AKPS) represents a significant problem for patients and sports medicine clinicians. Many predisposing factors have been associated with AKPS. Considerable attention has been given to quadriceps strengthening. Specifically the vastus medialis oblique (VMO) muscle is targeted for selective strengthening. Because of the VMO's oblique attachment to the patella, researchers report that proper dynamic alignment of the patella is dependent on VMO control. Given the lack of scientific information and agreement concerning the rehabilitation of patients with AKPS, the clinician and patient often become frustrated with the lack of progress during rehabilitation. Therefore the purpose of this paper is to clarify the current literature concerning the role of the VMO.
Esther Suter, Walter Herzog, Kelly De Souza and Robert Bray
The present study was aimed at determining muscle inhibition (MI) and knee extensor moments in 42 subjects with unilateral anterior knee pain syndrome. The results were compared to a normal, healthy population with no history of knee injury. Also, the effects of 1 week of a nonsteroidal anti-inflammatory drug (NSAID) on MI and knee extensor moments were tested in a randomized controlled trial. At baseline, the involved leg showed significantly higher MI than the noninvolved leg. In both legs, MI was significantly higher and knee extensor moments lower than the corresponding values of the nonimpaired subjects. There was a direct relationship between knee pain during testing and the extent of MI. Higher MI, in turn, was associated with lower knee extensor moments. The study demonstrated significant MI in the quadriceps muscles of the involved and noninvolved legs of subjects with unilateral anterior knee pain syndrome. The results indicate that the noninvolved leg cannot be considered a normal control for a contralateral injury. NSAIDs did not affect MI or knee extensor moments, despite significantly reducing pain. This finding suggests that factors other than pain are responsible for the MI observed in this specific subject population, or that after removal of pain, more time is required to fully restore muscle function.
Pedro Rodrigues, Trampas TenBroek and Joseph Hamill
“Excessive” pronation is often implicated as a risk factor for anterior knee pain (AKP). The amount deemed excessive is typically calculated using the means and standard deviations reported in the literature. However, when using this method, few studies find an association between pronation and AKP. An alternative method of defining excessive pronation is to use the joints’ available range of motion (ROM). The purposes of this study were to (1) evaluate pronation in the context of the joints’ ROM and (2) compare this method to traditional pronation variables in healthy and injured runners. Thirty-six runners (19 healthy, 17 AKP) had their passive pronation ROM measured using a custom-built device and a motion capture system. Dynamic pronation angles during running were captured and compared with the available ROM. In addition, traditional pronation variables were evaluated. No significant differences in traditional pronation variables were noted between healthy and injured runners. In contrast, injured runners used significantly more of their available ROM, maintaining a 4.21° eversion buffer, whereas healthy runners maintained a 7.25° buffer (P = .03, ES = 0.77). Defining excessive pronation in the context of the joints’ available ROM may be a better method of defining excessive pronation and distinguishing those at risk for injury.
Randon Hall, Kim Barber Foss, Timothy E. Hewett and Gregory D. Myer
To determine if sport specialization increases the risk of anterior knee pain in adolescent female athletes.
Retrospective cohort epidemiology study.
Female basketball, soccer, and volleyball players (N = 546) were recruited from a single county public school district in Kentucky consisting of 5 middle schools and 4 high schools. A total of 357 multisport and 189 single-sport (66 basketball, 57 soccer, and 66 volleyball) athlete subjects were included due to their diagnosis of patellofemoral pain (PFP) on physical exam. Testing consisted of a standardized history and physician-administered physical examination to determine the presence of PFP. This study compared self-reported multisport athletes with sport-specialized athletes participating in only 1 sport. The sports-participation data were normalized by sport season, with each sport accounting for 1 season of exposure. Incidence rate ratios and 95% confidence intervals (CI) were calculated and used to determine significant differences between athletes who specialized in sport in early youth and multisport athletes.
Specialization in a single sport increased the relative risk of PFP incidence 1.5-fold (95% CI 1.0−2.2, P = .038) for cumulative PFP diagnoses. Specific diagnoses such as Sinding Larsen Johansson/patellar tendinopathy (95% CI 1.5−10.1, P = .005) and Osgood Schlatter disease (95% CI 1.5−10.1, P = .005) demonstrated a 4-fold greater relative risk in single-sport compared with multisport athletes. Incidence of other specific PFP diagnoses such as fat pad, plica, trauma, pes anserine bursitis, and iliotibial-band tendonitis was not different between single-sport and multisport participants (P > .05).
Early sport specialization in female adolescents is associated with increased risk of anterior knee-pain disorders including PFP, Osgood Schlatter, Sinding Larsen-Johansson compared with multisport athletes.
Samantha A. Campbell and Alison R. Valier
Patellofemoral pain syndrome (PFPS) occurs in 25% of adolescents and adults and is the leading cause of knee pain in runners. Pain is commonly felt when ascending or descending stairs, deep squatting, kneeling, or running. There is no consensus on the etiology of this condition, but insufficient hip strength, malalignment of the lower extremity, hyperpronation of the foot, and patellar incongruence have been suggested. Common treatments of PFPS include strengthening of quadriceps and hip muscles, McConnell taping, electrical stimulation, and foot orthotics, but effectiveness of these treatments is inconclusive. Kinesio Taping is an alternative taping technique for musculoskeletal injuries including PFPS. Although research suggests that Kinesio Taping decreases pain and improves range of motion for some musculoskeletal injuries, its effectiveness in decreasing pain in patients with PFPS in unknown. Furthermore, Kinesio Taping has not been compared with other taping techniques including McConnell taping.
Focused Clinical Question:
For patients with anterior knee pain consistent with PFPS, does treatment with Kinesio Taping decrease pain more than McConnell taping or no tape at all?
Jihong Park, Terry L. Grindstaff, Joe M. Hart, Jay N. Hertel and Christopher D. Ingersoll
Weight-bearing (WB) and non-weight-bearing (NWB) exercises are commonly used in rehabilitation programs for patients with anterior knee pain (AKP).
To determine the immediate effects of isolated WB or NWB knee-extension exercises on quadriceps torque output and activation in individuals with AKP.
A single-blind randomized controlled trial.
30 subjects with self-reported AKP.
Subjects performed a maximal voluntary isometric contraction (MVIC) of the quadriceps (knee at 90°). Maximal voluntary quadriceps activation was quantified using the central activation ratio (CAR): CAR = MVIC/(MVIC + superimposed burst torque). After baseline testing, subjects were randomized to 1 of 3 intervention groups: WB knee extension, NWB knee extension, or control. WB knee-extension exercise was performed as a sling-based exercise, and NWB knee-extension exercise was performed on the Biodex dynamometer. Exercises were performed in 3 sets of 5 repetitions at approximately 55% MVIC. Measurements were obtained at 4 times: baseline and immediately and 15 and 30 min postexercise.
Main Outcome Measures:
Quadriceps torque output (MVIC: N·m/Kg) and quadriceps activation (CAR).
No significant differences in the maximal voluntary quadriceps torque output (F 2,27 = 0.592, P = .56) or activation (F 2,27 = 0.069, P = .93) were observed among the 3 treatment groups.
WB and NWB knee-extension exercises did not acutely change quadriceps torque output or activation. It may be necessary to perform exercises over a number of sessions and incorporate other disinhibitory interventions (eg, cryotherapy) to observe acute changes in quadriceps torque and activation.
Pablo Fanlo-Mazas, Elena Bueno-Gracia, Alazne Ruiz de Escudero-Zapico, José Miguel Tricás-Moreno and María Orosia Lucha-López
pain severity ratings in centimeters. The pain VAS has well-established reliability and validity in individuals with PFPS. 34 – 36 The Anterior Knee Pain Scale (AKPS) The AKPS consists of 13 items with discrete categories related to limp, weight-bearing, walking, stairs, squatting, running, jumping