Idiopathic anterior knee pain in adolescents

The Influence of the Q-Angle and Muscle Strength on Idiopathic Anterior Knee Pain in Adolescents

Background and Objectives: Idiopathic anterior knee pain is a common condition in adolescents and is mostly of unknown cause. The aim of this study was to examine the influence of the Q-angle and muscle strength on idiopathic anterior knee pain. Materials and Methods: Seventy-one adolescents (41 females and 30 males) diagnosed with anterior knee pain were included in this prospective study. The extensor strength in the knee joint and the Q-angle were monitored. The healthy extremity was used as a control. The Student's paired sample t-test was applied for testing the difference. Statistical significance was set at 0.05. Results: There was no statistically significant difference in the Q-angle value between the idiopathic AKP and the healthy extremity (p > 0.05) within the entire sample. A statistically significant higher Q-angle of the idiopathic AKP knee (p < 0.05) was obtained in the female subgroup. No statistically significant difference (p > 0.05) was found in the male subgroup. Within the male subgroup, the strength of the extensors within the knee joint of the healthy extremity had statistically significant higher values than the strength of these muscles in the affected extremity (p < 0.05). Conclusion: A greater Q-angle is a risk factor linked to anterior knee pain within the female population. Decreased muscle strength of knee joint extensors is a risk factor linked to anterior knee pain in both sex subgroups.

The Tibial Tubercle-Trochlear Groove Distance Is Greater in Patients With Patellofemoral Pain: Implications for the Origin of Pain and Clinical Interventions

BACKGROUND

The distance between the tibial tubercle (TT) and trochlear groove (TT-TG distance) is known to be greater in patients with patellar instability. However, the potential role and prevalence of pathological TT-TG distances in a large cohort of skeletally mature patients with isolated patellofemoral pain (PFP) are not clear.

PURPOSE

To determine if the mean TT-TG distance is greater in patients with PFP, who lack a history of patellar dislocations, knee trauma, or osteoarthritis, relative to healthy controls.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 50 knees (38 patients) with PFP and 60 knees (56 controls) without PFP formed the basis of this study. Magnetic resonance imaging was used to determine the TT-TG distance from 3-dimensional static scans.

RESULTS

The cohort with PFP demonstrated a significantly greater mean TT-TG distance relative to asymptomatic controls (13.0 vs 10.8 mm, respectively; P = .001). Among the cohort with PFP, 15 knees (30%) demonstrated TT-TG distances ≥15 mm, and 3 knees (6%) demonstrated TT-TG distances ≥20 mm.

CONCLUSION

Most adult patients with isolated PFP have elevated TT-TG distances compared with controls, which likely contributes to the force imbalance surrounding the knee.

Patellar Maltracking Persists in Adolescent Females With Patellofemoral Pain: A Longitudinal Study

Background:

Patellofemoral pain is one of the most common conditions seen in sports medicine practices, particularly among adolescent females. However, the natural history of the underlying pathology in patellofemoral pain during puberty remains poorly understood.

Purpose:

The purpose of this longitudinal study is to assess changes in patellar maltracking patterns in subjects with patellofemoral pain as they mature from mid- to late adolescence.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Three-dimensional patellofemoral kinematic data were acquired during active knee extension-flexion using dynamic magnetic resonance imaging in 6 girls (10 knees; mean age, 14.0 years) with clinically diagnosed patellofemoral pain. The subjects then returned as late adolescents (mean age, 18.5 years) for follow-up scanning. Three-dimensional patellofemoral kinematic parameters were evaluated across the range of motion, but comparison between time points was restricted to 10° of flexion. Participation in impact and nonimpact physical activities, pain score based on the visual analog scale, and the anterior knee pain score were also compared across initial and follow-up visits.

Results:

All subjects reported improved patellofemoral pain symptoms at follow-up, and one subject reported complete resolution. However, relative to the initial visit, no differences were found in patellar maltracking. There was a decrease in hours engaged in impact physical activities for all subjects at follow-up.

Conclusion:

This study provides insight into the natural history of patellofemoral pain in adolescent females. The relatively unchanged patellofemoral maltracking across subjects suggests that potential anatomic and kinematic abnormalities contributing to patellofemoral pain during mid-adolescence persist during skeletal maturation. Symptom improvement for these subjects did not result from a change in patellofemoral tracking, but rather from other causes.

The effects of medial synovial plica excision with and without lateral retinacular release on adolescents with anterior knee pain

OBJECTIVES

To describe the functional outcomes in patients aged ≤18 years with anterior knee pain treated with medial plica excision with or without lateral release.

METHODS

We identified 135 patients including 30 bilateral cases (165 knees) with a mean ± SD age of 15.1 ± 2.0 years. Patient and surgical information was recorded and a follow-up athletic questionnaire and an International Knee Documentation Committee (IKDC) Subjective Knee Evaluation form were sent out. Statistical analysis evaluated predictors of residual pain, reoperation, return to sports, IKDC score and satisfaction with surgery.

RESULTS

At a final mean follow-up of 4.4 years (range 2-7.5), 36 % of patients were pain free, 46 % had mild residual pain and 18 % had pain not improved from surgery. Reoperation was more likely following isolated plica excision (7/41; 17 %) versus plica excision with lateral release (8/124; 6 %), although not statistically significant, P = 0.06. Mean IKDC score (107 knees) was 76.9 ± 17.8 (range 31-100). Most patients (86/99; 87 %) were satisfied with surgery and were able to return to sports (104/120; 87 %).

CONCLUSIONS

While most patients were satisfied and able to return to sports following plica excision with or without lateral release, residual symptoms were common.

Diagnostic Differences for Anterior Knee Pain between Sexes in Adolescent Basketball Players

BACKGROUND

The purpose of this study was to determine if there is a sex difference in the prevalence of specific patellofemoral disorders that cause anterior knee pain in adolescent basketball players undergoing pre-participation screening.

METHODS: SETTING

Biomechanical Laboratory.

METHODS: PARTICIPANTS

A total of 810 (688 female and 122 male) basketball players from a single county public school district.

METHODS: MAIN OUTCOME MEASURES

Prior to the start of three consecutive basketball seasons, participants were evaluated for anterior knee pain. Testing consisted of completion of the Anterior Knee Pain Scale. Those with positive findings completed an IKDC form, a standardized history and a physician-administered physical examination.

RESULTS

Anterior knee pain was noted in 410 of 1620 knees (25.3%). 26.6% of female knees and 18.0% of male knees were affected (p<0.05). Patellofemoral dysfunction (PFD) was the most common diagnosis with an overall prevalence of 6.4% (7.3% females; 1.2% males). Less common were Sinding-Larsen-Johanssen disease (SLJ), 4.8% (5.0% females; 3.7% males), Osgood-Schlatter Disease (OSD) 2.5% (2.3% females; 4.1% males); and plica syndrome 2.3% (2.1% females; 3.3% males). The remaining diagnoses (trauma, fat pad syndrome, IT band and pes anserine bursitis) had a combined prevalence of 1.7% (1.9% females; 1.6% males).

CONCLUSIONS

PFD was significantly more common in females (p<0.05). Anterior knee pain was more common in adolescent female basketball players than in adolescent male basketball players.

LEVEL OF EVIDENCE

Descriptive Laboratory Study. Level 1.

Expected prevalence from the differential diagnosis of anterior knee pain in adolescent female athletes during preparticipation screening

CONTEXT

Anterior knee pain is a common disorder in female athletes with an undefined cause. The relative prevalence of specific patellofemoral disorders associated with anterior knee pain in adolescent females remains undetermined.

OBJECTIVE

To determine the prevalence of specific patellofemoral disorders obtained using the differential diagnosis of anterior knee pain in adolescent female athletes during preparticipation screening.

DESIGN

Descriptive epidemiology study.

SETTING

Preparticipation screening evaluations at a county public school district in Kentucky.

PATIENTS OR OTHER PARTICIPANTS

A total of 419 unique middle and high school-aged female athletes.

MAIN OUTCOME MEASURE(S)

Participants were evaluated by physicians for anterior knee pain over 3 consecutive basketball seasons. Given the longitudinal nature of this study, some participants were tested longitudinally over multiple years.

RESULTS

Over the course of 3 basketball seasons, 688 patient evaluations were performed. Of these, 183 (26.6%) were positive for anterior knee pain. A statistically significant difference was noted in the prevalence of anterior knee pain by school level, with 34.4% (n = 67) in high school-aged athletes versus 23.5% (n = 116) in middle school-aged athletes (P < .05). In the 1376 knees evaluated, patellofemoral dysfunction was the most common diagnosis, with an overall prevalence of 7.3% (n = 100). The only diagnosis shown to be statistically different between age levels was Sinding-LarsenJohansson disease or patellar tendinopathy, with 38 cases (9.7%) in high school-aged and 31 (3.1%) in middle school-aged athletes (P < .05).

CONCLUSIONS

Anterior knee pain was present in 26.6% of the adolescent female athletes screened over 3 years. Symptoms of anterior knee pain likely persist after middle school-aged onset and reach peak prevalence during the high school years.

Review for the generalist: evaluation of anterior knee pain

Anterior knee pain is common in children and adolescents. Evaluation and management is challenging and requires a thorough history and physical exam, and understanding of the pediatric skeleton. This article will review common causes of chronic anterior knee pain in the pediatric population with a focus on patellofemoral pain.

Anterior knee pain

Anterior knee pain is a common complain in all ages athletes. It may be caused by a large variety of injuries. There is a continuum of diagnoses and most of the disorders are closely related. Repeated minor trauma and overuse play an important role for the development of lesions in Hoffa's pad, extensor mechanism, lateral and medial restrain structures or cartilage surface, however usually an increase or change of activity is referred. Although the direct relation of cartilage lesions, especially chondral, and pain is a subject of debate these lesions may be responsible of early osteoarthrosis and can determine athlete's prognosis. The anatomy and biomechanics of patellofemoral joint is complex and symptoms are often unspecific. Transient patellar dislocation has MR distinct features that provide evidence of prior dislocation and rules our complication. However, anterior knee pain more often is related to overuse and repeated minor trauma. Patella and quadriceps tendon have been also implicated in anterior knee pain, as well as lateral or medial restraint structures and Hoffa's pad. US and MR are excellent tools for the diagnosis of superficial tendons, the advantage of MR is that permits to rule out other sources of intraarticular derangements. Due to the complex anatomy and biomechanic of patellofemoral joint maltracking is not fully understood; plain films and CT allow the study of malalignment, new CT and MR kinematic studies have promising results but further studies are needed. Our purpose here is to describe how imaging techniques can be helpful in precisely defining the origin of the patient's complaint and thus improve understanding and management of these injuries.

Musculoskeletal injuries in sports

A large number of adolescents participate in various sports. Not withstanding the methodologic problems with epidemiologic data, a large percentage of athletes sustain musculoskeletal injuries. In most instances, the athlete first presents to his or her primary care physician, who must perform the initial assessment and decide on further management. Many injuries can be managed by the primary care physician. It is important to recognize the unique characteristics of adolescent growth and development that have implications for the diagnosis and management of musculoskeletal injuries.