Patellofemoral pain in athletes: clinical perspectives

Is There an Association Between Injury History and Lower Extremity Joint Injury During Canada Games Competition?

Background

Injuries during elite level competition like the Canada Games, occur frequently and injury history is one of the strongest predictors of future injury; however, this association is unknown in the Canada Games.

Purpose

To determine the association between injury history and incidence of lower extremity joint injury during Canada Games competition.

Methods

Data from the 2009 - 2019 Canada Games (8710 male and 8391 female athletes) competitions were de-identified by the Canada Games Council for analysis. Injury data were cleaned and categorized for previous injury and injury type and location. Injury history was self-reported and included concussion, major surgical procedure, neck and back, trauma to joint or bone, and trauma to ligament or tendon. Injury from the Canada Games competitions were categorized to include ankle, knee, hip, and patellofemoral joint injuries. Chi-Square (χ2 ) test of independence determined association between injury history and incidence of lower extremity joint injury during Canada Games competition. IBM SPSS (Version 26) was used for statistical analysis (p-value < 0.05).

Results

Four hundred and seventy-five ankle, 503 knee, 253 hip, and 106 patellofemoral joint injuries were reported during 10 years of Canada Games competitions. There were significant associations between history of neck and back injuries with ankle injuries and knee injuries, history of trauma and overuse of ligament or tendon with hip injuries and history of trauma or overuse of joint or bone with patellofemoral joint injuries.

Conclusion

These findings support previous literature suggesting that injury history is associated with future injury.

Level of Evidence

3.

Patellofemoral Pain Syndrome Is Associated With Chronic Disease and Allergies in 60 997 Distance Runner Race Entrants: SAFER XXX Study

OBJECTIVE

Patellofemoral pain syndrome (PFPS) is a common running-related injury. Independent risk factors associated with PFPS have not been described in a large cohort of distance runners.

DESIGN

Descriptive, cross-sectional study.

SETTING

21.1 and 56 km Two Oceans Marathon races (2012-2015).

PARTICIPANTS

60 997 race entrants.

ASSESSMENT OF RISK FACTORS

Participants completed a compulsory prerace medical screening questionnaire (history of PFPS in the past 12 months, n = 362; no injury history, n = 60 635). Selected risk factors associated with a history of PFPS were explored using univariate & multivariate analyses: demographics, training/running variables, history of chronic diseases (composite chronic disease score), and any allergy.

MAIN OUTCOME MEASURES

Prevalence ratios (PRs, 95% confidence intervals).

RESULTS

Risk factors associated with PFPS (univariate analysis) were increased years of recreational running (PR = 1.09; P = 0.0107), older age (>50 years), and chronic diseases (PR > 2): gastrointestinal disease (PR = 5.06; P < 0.0001), cardiovascular disease (CVD) (PR = 3.28; P < 0.0001), nervous system/psychiatric disease (PR = 3.04; P < 0.0001), cancer (PR = 2.83; P = 0.0005), risk factors for CVD (PR = 2.42; P < 0.0001), symptoms of CVD (PR = 2.38; P = 0.0397), and respiratory disease (PR = 2.00; P < 0.0001). Independent risk factors (multivariate analysis) associated with PFPS (adjusted for age, sex, and race distance) were a higher chronic disease composite score (PR = 2.68 increased risk for every 2 additional chronic diseases; P < 0.0001) and a history of allergies (PR = 2.33; P < 0.0001).

CONCLUSIONS

Novel independent risk factors associated with PFPS in distance runners are a history of multiple chronic diseases and a history of allergies. Identification of chronic diseases and allergies should be considered as part of the clinical assessment of a runner presenting with a history of PFPS.

Knee Injury and Osteoarthritis Outcome Score Patellofemoral Questionnaire: Psychometric Properties among Females of Kingdom of Saudi Arabia

Patellofemoral joint osteoarthritis (PFJ-OA), being a subset of knee osteoarthritis (KOA), is evident in adults, and its prevalence is greater in women in Saudi Arabia too. To assess its disease dimensions, the 'Knee Injury and Osteoarthritis Outcome Score Patellofemoral' questionnaire (KOOS-PF) is frequently used to measure symptoms and function among the people with PFJ-OA. Cross-cultural validation is ongoing in several languages, and it needed to be validated among females in Arabic. Therefore, aiming to translate, cross-culturally adapt and validate its psychometric properties, a cross-sectional study was designed where the Ar-KOOS-PF-F was administered among 105 females. The demographic characteristics of recruited females were 51.62 (8.49) years and 30.12 (3.70) kg/m2. Cronbach's alpha was used for internal consistency (IC) and the questionnaire was re-administered after 48 h to estimate the test-retest reliability (92 females, 87.61% compliance rate). Concurrent validity was also established with a visual analog scale (VAS). Factorial validity was established by principal component analysis (PCA). The psychometric properties were: excellent internal consistency of Cronbach's alpha (α) = 0.930, intraclass correlation coefficient (ICC) for intra-ratter reliability = 0.960 (0.915-0.999), test-retest reliability, ICC = 0.893 (0.889-0.970), standard error of measurement (SEM) = 2.46, relative standard deviation/coefficient of variance (RSD/CV) = 29.9%, minimal detectable change (MDC%) = 22.96% and good concurrent validity with VAS (r = -0.783; p = 0.023). The best-fit four-factor model for confirming overall item communalities ranged from 0.529 to 0.867, which indicates moderate to high communalities, and confirms the homogeneity of Ar-KOOS-PF-F using PCA. The floor (0.9%) and ceiling effects (13.6%) were also within the limits. This scale can be used among females, as it has acceptable psychometric properties of scale validation.

Understanding the Cheerleader as an Orthopaedic Patient: An Evidence-Based Review of the Literature

Cheerleading is a highly popular youth sport in the United States and has been increasingly recognized in recent years for its athleticism and competitive nature. The sport has changed dramatically since its inception. When the sport of cheerleading was first developed, its primary purpose was to entertain crowds and support other athletes. Today, cheerleaders are competitive athletes themselves. Cheerleaders, most of whom are in the pediatric age group, and their parents commonly approach orthopaedic surgeons and sports medicine physicians with questions regarding the risks associated with participation in the sport. Appropriate clinical guidance is especially important for athletes returning to the sport after an injury. However, unlike other popular sports (eg, football, basketball, and volleyball), the intricacies of cheerleading are not well-known to those outside the sport, including many health care providers. Previous studies have reported on the epidemiological patterns of injuries associated with cheerleading and how such aesthetic sports affect the body, finding that fractures and concussions are prevalent and that catastrophic injuries are more common than in most other sports. Here, we provide an evidence-based discussion of 10 pertinent topics regarding cheerleading and its risks to the musculoskeletal system. The purpose of this review is to provide a comprehensive resource for orthopaedic surgeons and sports medicine physicians who care for these athletes.

Trunk, pelvis, and knee kinematics during running in females with and without patellofemoral pain

BACKGROUND

Females are two times more likely to develop patellofemoral pain (PFP) than males. Abnormal trunk and pelvis kinematics are thought to contribute to the pathomechanics of this condition. However, there is a scarcity of evidence investigating proximal segments kinematics in females with PFP.

RESEARCH QUESTION

The purpose of this study was to investigate whether females with PFP demonstrate altered trunk, pelvis, and knee joint kinematics compared with healthy controls during running.

METHODS

Thirty-four females (17 PFP, 17 controls) underwent a 3-dimensional motion analysis during treadmill running at preferred and fixed speeds, each trial for 30 s. Variables of interest included magnitudes of peak angles for trunk (forward flexion, ipsilateral trunk lean), pelvis (anterior tilt, contralateral drop), knee (flexion, valgus, internal rotation), range of motion (RoM) of trunk and pelvis in sagittal and frontal planes and RoM of knee joint in the three cardinal planes of motion. Kinematic data were compared between groups using mixed model repeated measure analysis of variance with the trial as the repeated measure.

RESULTS

The PFP group displayed significantly less pelvis frontal plane RoM, greater knee frontal plane RoM, and less knee sagittal plane RoM during running compared with controls, irrespective of running trial. No differences were found in peak kinematic variables between PFP and healthy groups.

SIGNIFICANCE

These results may suggest a rigid stabilization strategy at the pelvis, which the body has adapted to prevent further frontal plane knee malalignment. Less knee sagittal plane RoM may be indicative of another protective strategy in the PFP group to avoid patellofemoral joint reaction force. Clinical assessments and rehabilitative treatments may benefit from considering a global program with focus on pelvis kinematics in addition to the knee joint in females with PFP.

Prevalence and pain distribution of anterior knee pain in college basketball players

CONTEXT

Causes of anterior knee pain (AKP) in jumping athletes include patellofemoral pain and patellar tendinopathy. Differential diagnosis of AKP is challenging, with variation in clinical presentations. No previous research has used pain location to describe AKP in basketball athletes.

OBJECTIVES

To describe the prevalence and pain distribution of AKP in college basketball. To report the prevalence of focal inferior pole pain using two outcome measures.

DESIGN

Cross-sectional study Setting: University and college basketball facilities in Alberta, Canada.

PATIENTS OR OTHER PARTICIPANTS

242 collegiate basketball athletes Main Outcome Measure(s): The single leg decline squat test (SLDS) was used to capture pain location using pain mapping (dichotomised into focal/diffuse) and pain severity (numerical rating scale). The Oslo Sports Trauma Research Centre Knee questionnaire (OSTRC-Knee) and adapted version for patellar tendinopathy (OSTRC-P) were used to report the prevalence of anterior knee pain (AKP) and patellar tendinopathy respectively. Focal inferior pole pain during the SLDS was used to classify patellar tendinopathy.

RESULTS

Of the 242 players (138 women, 104 men), 146 (60%) reported pain with the SLDS [unilateral n=64, (26%); bilateral n=82 (34%)]. 101 (43%) reported knee pain using the OSTRC-Knee. Pain mapping captured variability in pain location. Diffuse pain was more prevalent [left 70%; right 72%] than focal pain [left 30%; right 28%]. There was low prevalence of patellar tendinopathy with either outcome measure; OSTRC-P [n=21, 8.7%] and inferior pole pain during the SLDS [n=25, 10.3%] Conclusions: Diffuse AKP was common in Canadian basketball players, however pain mapped to the inferior pole of the patella was not. Few players reported tendinopathy using the OSTRC-P, suggesting that patellar tendinopathy was not a primary knee pain presentation in this jumping cohort. Pain location rather than presence or severity of pain alone may better describe the clinical presentations of AKP in jumping athletes.

Effectiveness of physiotherapy interventions for injury in ballet dancers: A systematic review

Background

The unique repetitive nature of ballet dancing, which often involves transgressing endurance limits of anatomical structures, makes dancers prone to injury. The following systematic review aims to assess the effectiveness of physiotherapy interventions in the treatment of injuries in ballet dancers.

Methods

The review was performed in line with the PRISMA statement on preferred reporting items for systematic reviews and meta-analyses. Six electronic databases (PubMed, Ovid Embase, Cochrane, Medline, PEDro, Google Scholar) were queried. The study populations comprised active ballet dancers and/or ballet school attendees with acute and chronic injuries and those with persistent pain. There were no restrictions regarding age, sex, ethnicity or nationality. The Modified McMaster Critical Review Form for quantitative studies was used to assess the methodological quality of the studies reviewed in accordance with the relevant guidelines.

Results

Out of the total of 687 articles subjected to the review, 10 met the inclusion criteria. Diverse physiotherapeutic interventions were described and effectiveness was assessed using different parameters and measurements. Overall, the results indicate that physiotherapy interventions in ballet dancers exert a positive effect on a number of indices, including pain, ROM and functional status.

Conclusions

Due to the small amount of evidence confirming the effectiveness of physiotherapeutic interventions in ballet dancers after injuries and methodological uncertainties, it is recommended to improve the quality of prospective studies.

Thai version of the Survey Instrument for Natural History, Aetiology and Prevalence of Patellofemoral Pain: Cross-cultural validation and test-retest reliability

Background

/objective: The Survey Instrument for Natural History, Aetiology and Prevalence of Patellofemoral Pain (SNAPPS) is a self-report questionnaire which is a specifically designed measurement instrument to identify patellofemoral pain. It has reported high sensitivity, specificity and test-retest reliability to discriminate between people with knee pain, with or without patellofemoral pain. SNAPPS hasn't been studied in Thailand; therefore, the aim of this study was to cross-culturally adapt the questionnaire into Thai.

Method

This study was separated into two phases: cross-cultural adaptation and test-retest reliability. The Survey Instrument for Natural History, Aetiology and Prevalence of Patellofemoral Pain was translated into Thai following the guidelines for the cross cultural adaptation of self-report measures including six steps. Thirty four knee pain patients performed the test-retest reliability of the final version of this questionnaire. They were clinically diagnosed with patellofemoral pain by a physical therapist. They were asked to complete the questionnaire twice; with the 1st session and 2nd session having a 30 min break between. The intraclass correlation coefficient (ICC_{3, 1}) method was used to determine test-retest reliability. The correlation of SNAPPS and VAS-U, VAS-W, VAS-S, VAS- J, VAS- R, and VAS- SQ were analyzed by Pearson correlation.

Results

The thirty-four participants (19 males, 15 females; with ages ranging 19–24 years) with patellofemoral pain were assessed twice with a 30 min break between the two sessions. The total scores of section 2 and 4 of the questionnaire indicated very strong test-retest reliability, ranging from 0.83 to 0.954 and the total score was ICC 0.91. Moreover, the Survey Instrument for Natural History, Aetiology and Prevalence of Patellofemoral Pain had a correlation with intensity of pain during ascending and descending stairs.

Conclusion

The Thai version of the Survey Instrument for Natural History, Aetiology and Prevalence of Patellofemoral Pain can be used to assess patellofemoral pain in young Thai patients.

Ankle Dorsiflexion Affects Hip and Knee Biomechanics During Landing

BACKGROUND

Restricted ankle dorsiflexion range of motion (DFROM) has been linked to lower extremity biomechanics that place an athlete at higher risk for injury. Whether reduced DFROM during dynamic movements is due to restrictions in joint motion or underutilization of available ankle DFROM motion is unclear.

HYPOTHESIS

We hypothesized that both lesser total ankle DFROM and underutilization of available motion would lead to high-risk biomechanics (ie, greater knee abduction, reduced knee flexion).

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Nineteen active female athletes (age, 20.0 ± 1.3 years; height, 1.61 ± 0.06 m; mass, 67.0 ± 10.7 kg) participated. Maximal ankle DFROM (clinical measure of ankle DFROM [DF-CLIN]) was measured in a weightbearing position with the knee flexed. Lower extremity biomechanics were measured during a drop vertical jump with 3-dimensional motion and force plate analysis. The percent of available DFROM used during landing (DF-%USED) was calculated as the peak DFROM observed during landing divided by DF-CLIN. Univariate linear regressions were performed to identify whether DF-CLIN or DF-%USED predicted knee and hip biomechanics commonly associated with injury risk.

RESULTS

For every 1.0° less of DF-CLIN, there was a 1.0° decrease in hip flexion excursion (r² = 0.21, P = 0.05), 1.2° decrease in peak knee flexion angles (r² = 0.37, P = 0.01), 0.9° decrease in knee flexion excursion (r² = 0.40, P = 0.004), 0.002 N·m·N^-1·cm^-1 decrease in hip extensor work (r² = 0.28, P = 0.02), and 0.001 N·m·N^-1·cm^-1 decrease in knee extensor work (r² = 0.21, P = 0.05). For every 10% less of DF-%USED, there was a 3.2° increase in peak knee abduction angles (r² = 0.26, P = 0.03) and 0.01 N·m·N^-1·cm^-1 lesser knee extensor work (r² = 0.25, P = 0.03).

CONCLUSION

Lower levels of both ankle DFROM and DF-%USED are associated with biomechanics that are considered to be associated with a higher risk of sustaining injury.

CLINICAL RELEVANCE

While total ankle DFROM can predict some aberrant movement patterns, underutilization of available ankle DFROM can also lead to higher risk movement strategies. In addition to joint specific mobility training, clinicians should incorporate biomechanical interventions and technique feedback to promote the utilization of available motion.

Isolated medial patellofemoral ligament reconstruction for recurrent patellofemoral instability: analysis of outcomes and risk factors

Background

The medial patellofemoral ligament (MPFL) is always damaged after patellar dislocation. In selected patients, MPFL reconstruction is necessary to restore a correct patellar tracking. Despite the large number of different techniques reported to reconstruct the MPFL, there is no consensus concerning the optimal procedure, and debates is still ongoing. The present study analysed the results after isolated MPFL reconstruction in patients with patellofemoral instability. Furthermore, a subgroup analysis of patients presenting pathoanatomical risk factors was made.

Methods

In November 2020, the main electronic databases were accessed. All articles reporting the results of primary isolated MPFL reconstruction for recurrent patellofemoral instability were considered for inclusion. Only articles reporting a minimum 12-month follow-up were eligible.

Results

Data from a total of 1777 knees were collected. The mean age of the patients involved was 22.8 ± 3.4 years. The mean follow-up was 40.7 ± 25.8 months. Overall, the range of motion (+ 27.74; P < 0.0001) and all the other scores of interests improved at last follow-up: Kujala (+ 12.76; P = 0.0003), Lysholm (+ 15.69; P < 0.0001), Tegner score (+ 2.86; P = 0.006). Seventy-three of 1780 patients (4.1%) showed a positive apprehension test. Thirty of 1765 patients (1.7%) experienced re-dislocations, while 56 of 1778 patients (3.2%) showed persisting joint instability. Twenty-five of 1786 patients (1.4%) underwent revision surgeries.

Conclusion

Isolated MPFL reconstruction for recurrent patellofemoral instability provides reliable surgical outcomes. Patients with pathoanatomical predisposing factors reported worse surgical outcomes.

Effects of Trigger Point Dry Needling on Neuromuscular Performance and Pain of Individuals Affected by Patellofemoral Pain: A Randomized Controlled Trial

Purpose

To investigate the effects of trigger point dry needling (TrP-DN) on exercise-induced patellofemoral pain syndrome (PFPS).

Patients and Methods

In this randomized, single-blind, parallel-group trial, 50 patients with PFPS were randomly allocated to the following two groups: the TrP-DN group (n = 25) and the Sham needling group (n = 25). Patients in both groups were asked to perform a stretching exercise of the quadriceps daily after needling. The needling group received a single session of TrP-DN to trigger points (TrPs) in the vastus medialis oblique (VMO), vastus lateralis (VL), and rectus femoris muscles (once a week for 6 weeks), and the Sham group received placebo needling. Visual analogue scale (VAS) for pain intensity and Kujala questionnaire for the functional status were assessed before treatment, 3 and 6 weeks after treatment, and at the 3-month follow-up. The ratio of the myoelectric amplitude of the vastus medialis oblique and vastus lateralis muscles (VMO/VL) was assessed before treatment and 6 weeks after treatment.

Results

There was no significant difference in the general data between the two groups. The VAS scores and Kujala scores in the TrP-DN group were significantly improved and increased at the 3-week treatment visit, 6-week treatment visit, and 3-month follow-up compared to the scores before treatment; and the scores in the Sham group were only significantly improved at the 3-week treatment visit, and 6-week treatment visit. VAS scores in the TrP-DN group were significantly lower and Kujala scores were significantly higher at the 6-week treatment visit and the 3-month follow-up compared to those in the Sham group. The VMO/VL ratio in the TrP-DN group was significantly increased at the 6-week treatment visit compared to that before treatment.

Conclusion

TrP-DN at the quadriceps combined with stretch can reduce the pain, and improves the clinical symptoms and function, the VMO/VL ratio, and the coordination of VMO and VL in patients with PFPS.

A Pilot Study of Hip Corrective Taping Using Kinesio Tape for Pain and Lower Extremity Joint Kinematics in Basketball Players with Patellofemoral Pain

Purpose

This pilot study aimed to determine the feasibility of hip corrective taping to improve self-reported knee pain and lower extremity joint kinematics in basketball players with patellofemoral pain.

Patients and Methods

A single group pre-test and post-test design. Collegiate basketball players with patellofemoral pain were recruited. Three-dimensional hip and knee joint kinematics were measured during two tasks, single-leg squat (SLS) and lay-up jump (LUJ), and each task was conducted under no-taping and taping conditions. Subjective report of pain was compared between no-taping and taping conditions only during SLS.

Results

Twelve collegiate basketball players with patellofemoral pain (median age, 22.7 [2.5] years; mean height, 173.8 ± 7.4 cm; mean weight, 72.5 ± 12.8 kg) participated in this study. Compared with no-taping, the use of hip corrective taping significantly increased the hip abduction angle at the instant of the maximal vertical ground reaction force during LUJ (no-taping vs taping: 0.6° ± 6.3° vs 3.3° ± 5.1°, p = 0.029), and also caused a trend of decreased maximal hip internal rotation angle during SLS (no-taping vs taping: 8.0° ± 6.6° vs 4.7° ± 6.9°, p = 0.050). Hip corrective taping also improved self-reported knee pain during SLS (no-taping vs taping: 3.4 ± 1.7 vs 2.6 ± 1.0, p = 0.046).

Conclusion

Hip corrective taping may be used as an effective intervention for athletes with patellofemoral pain during basketball-related tasks.

Patellofemoral Pain

Patellofemoral pain (PFP) is a common musculoskeletal-related condition that is characterized by insidious onset of poorly defined pain, localized to the anterior retropatellar and/or peripatellar region of the knee. The onset of symptoms can be slow or acutely develop with a worsening of pain accompanying lower-limb loading activities (eg, squatting, prolonged sitting, ascending/descending stairs, jumping, or running). Symptoms can restrict participation in physical activity, sports, and work, as well as recur and persist for years. This clinical practice guideline will allow physical therapists and other rehabilitation specialists to stay up to date with evolving PFP knowledge and practices, and help them to make evidence-based treatment decisions. J Orthop Sports Phys Ther. 2019;49(9):CPG1-CPG95. doi:10.2519/jospt.2019.0302.

Imaging features in incident radiographic patellofemoral osteoarthritis: the Beijing Shunyi osteoarthritis (BJS) study

Background

The present study aims to describe the imaging features in incident radiographic patellofemoral osteoarthritis (RPFOA) population in a Chinese suburban area.

Methods

The Beijing Shunyi osteoarthritis (BJS) study was a population-based, longitudinal and prospective study. Residents were recruited by randomized cluster sampling in 2014 and were followed 3 years later. Home interviews and clinical examinations were performed; weight-bearing posterior-anterior semi-flexed (45-degree) views of the tibiofemoral (TF) joints and skyline (45-degree) views of the patellofemoral (PF) joints were included. For each batch of study films (n = 100), 20 films from the year 2014 and 20 previously read PF radiographs were fed back to test inter−/intra-reader repeatability. The imaging features of incident RPFOA were analyzed. Narrative statistics, independent-sample t-tests, and nonparametric tests were performed.

Results

A total of 1295 participants (2590 knees) were recruited at baseline in 2014, and 967 (74.7%) residents were followed in 2017. Of all the knees (n = 1537) without RPFOA at baseline, 139 knees (13.3%) across 119 people developed incident RPFOA. Compared with the whole population, age (p = 0.031), body mass index (BMI, p = 0.042), and incidence of knee pain symptoms (p < 0.01) were significantly different in the incident RPFOA population, while range of motion (ROM, p = 0.052) and gender (0/1, p = 0.203) showed no significance. In the incident population, the changes of each imaging indicator grade were evaluated—lateral patellofemoral osteophyte (LPOST, increased by 1.02), medial patellofemoral osteophyte (MPOST, increased by 0.49), lateral joint space narrowing (LJSN, increased by 0.30), medial joint space narrowing (MJSN, increased by 0.06); indicator grade progress decreases, respectively. The progress of LPOST was the fastest among the four indicators (p < 0.01).

Conclusions

In this population-based longitudinal study, among the incident RPFOA population, the imaging indicators show that marginal patellofemoral osteophyte is more pronounced than patellofemoral joint space narrowing. LPOST is the fastest-progressing indicator among all the radiographic features, which is also the most common imaging manifestation of RPFOA. In the incident RPFOA population, the proportion of elders, women, higher-BMI individuals, and people suffering knee pain is more than the normal population.

Epidemiological Patterns of Patellofemoral Injuries in Collegiate Athletes in the United States From 2009 to 2014

Background

As many as 30% of patients with knee pain seen in sports medicine clinics have complaints related to the patellofemoral joint. There is a paucity of research available regarding patellofemoral injuries, mechanism of injury, and playing time lost in collegiate athletes.

Purpose

To describe the rates, mechanisms, severity, and potential sex-based differences of patellofemoral injuries in collegiate athletes across 25 National Collegiate Athletic Association (NCAA) sports.

Study Design

Descriptive epidemiology study.

Methods

Data from the 2009-2010 through the 2013-2014 academic years were obtained from the NCAA Injury Surveillance Program and were analyzed to calculate patellofemoral injury rates, mechanisms of injury, time lost, and need for surgery. Rate ratios and injury proportion ratios were used to quantify discernible differences between sex-comparable sports and timing of injury (ie, practice vs competition), respectively.

Results

The overall patellofemoral injury incidence rate was 16.10 per 100,000 athlete-exposures (AEs). Women's volleyball had the highest incidence of all sports (39.57 per 100,000 AEs). Injuries were 66% more likely to occur in competition than during practice. Female athletes experienced significantly more patellofemoral injuries than males in similar sports. Patellar tendinitis accounted for 49.2% of all patellofemoral injuries and was the most common injury in 20 of 25 studied sports. Patellar subluxation accounted for the most total days missed, and patellar dislocation had the highest mean days missed per injury (11.42 days). Patella fracture was the most likely injury to require surgery (80%).

Conclusion

Patellofemoral injuries were most common in sports that require jumping and quick changes of direction, specifically women's volleyball, men's and women's basketball, and women's soccer. The majority of patellofemoral injuries in this cohort were classified as patellar tendinitis caused by overuse. Most injuries resulted in no competition or practice time lost. This information may contribute to the development of prevention programs aimed at addressing the most prevalent types and mechanisms of injury in each sport to reduce the incidence of patellofemoral injury in these athletes.