Patellofemoral Pain

Knee skin temperature response of patients with bilateral patellofemoral syndrome before and after heat and cold stress

Patellofemoral Pain Syndrome is characterized by the presence of pain in the front area of the knee, which occurs when performing common activities such as climbing stairs, and bending the knees, among others. The objective of this research was to evaluate the detection capability of infrared thermography in patients with Patellofemoral Pain Syndrome, in the baseline state, as well as after the application of thermal stress. The investigation was conducted in 48 patients, who were subdivided into four groups (n = 12). Two subgroups were healthy patients and two with Patellofemoral Pain Syndrome. For the diagnosis of the syndrome, a manual evaluation was performed using the Zohlen test and Q angle measurement. Subsequently, cold stress was applied for 10 min to a healthy subgroup and an experimental subgroup. The remaining two subgroups were subjected to heat stress for 15 min. Thermographic images of the lower extremities were acquired at seven time points, at baseline, immediately after application of thermal stress and then every 3 min until 15 min were completed. It was observed that patients presented Patellofemoral Pain Syndrome bilaterally. After statistical analysis, it was found that there were no significant differences in baseline temperature between the groups. However, for heat stress, a higher temperature was observed in the group with Patellofemoral Pain Syndrome (p < 0.05) in the recovery period, and in the case of cold stress, only a lower temperature in the left knee immediately after the application. In conclusion, it is not possible to detect patellofemoral syndrome bilaterally in the baseline state by thermography and neither is it evident in cold stress. However, after heat stress, thermal recovery is lower for the PFPS group, so it would be susceptible to detection.

The reliability of the patellotrochlear index on magnetic resonance imaging for measuring patellofemoral height

BACKGROUND

The purpose of this study was to determine the inter- and intra-observer reliability of the patellotrochlear index (PTI) on magnetic resonance images (MRI) in patients with patellofemoral pain. The correlation between the PTI measured on MRI and the modified Insall-Salvati (MIS) ratio measured on radiographs was also assessed.

METHODS

The PTI was assessed on MRI images and the MIS ratio on radiographs of 66 knees of 62 patients. Assessment was performed by two orthopaedic surgeons, one orthopaedic surgery registrar, two radiologists and one radiology registrar. Correlation coefficients, standard errors of measurement and limits of agreement were calculated for the PTI. To assess the association between the PTI and the MIS ratio, the Pearson's correlation coefficient was calculated.

RESULTS

The PTI showed good interobserver reliability (intraclass correlation coefficient (ICC) 0.79; 95% confidence interval (CI) 0.73-0.85) and excellent intra-observer reliability (ICC 0.90; 95% CI 0.89-0.91). The standard error of measurement was 0.05 and limits of agreement with the mean ± 0.09. A very weak and not significant correlation was found between the PTI and the MIS (r = 0.02; P = 0.77).

CONCLUSIONS

The PTI showed good interobserver reliability and excellent intra-observer reliability. In order to conclude which measurement method of assessing patellar height is truly the most reliable, future studies should investigate agreement parameters (standard error of measurement, limits of agreement) besides solely correlation coefficients. We found a very weak correlation between the PTI and the MIS which suggests that at least one index has poor validity. Future validity studies on indices to assess patellar height are necessary.

Clinical outcomes and predictive factors for failure with MPFL reconstruction combined with tibial tubercle osteotomy and lateral retinacular release for recurrent patellar instability

BACKGROUND

Medial patellofemoral ligament (MPFL) reconstruction combined with tibial tubercle osteotomy (TTO) and lateral retinacular release (LRR) is one of the main treatment methods for patellar instability. So far, few studies have evaluated the clinical effectiveness and assessed potential risk factors for recurrent patellar instability.

PURPOSE

To report the clinical outcomes of MPFL reconstruction combined with TTO and LRR at least three years after operation and to identify potential risk factors for recurrent patellar instability.

METHODS

A retrospective analysis of medical records for patients treated with MPFL, TTO and LRR from 2013 to 2017 was performed. Preoperative assessment for imaging examination included trochlear dysplasia according to Dejour classification, patella alta with the Caton-Deschamps index (CDI), tibial tubercle-trochlear groove distance. Postoperative assessment for knee function included Kujala, IKDC and Tegner scores. Failure rate which was defined by a postoperative dislocation was also reported.

RESULTS

A total of 108 knees in 98 patients were included in the study. The mean age at operation was 19.2 ± 6.1 years (range, 13-40 years), and the mean follow-up was 61.3 ± 15.4 months (range, 36-92 months). All patients included had trochlear dysplasia (A, 24%; B, 17%; C, 35%; D, 24%), and 67% had patellar alta. The mean postoperative scores of Tegner, Kujala and IKDC were 5.3 ± 1.3 (2-8), 90.5 ± 15.5 (24-100) and 72.7 ± 12.1 (26-86). Postoperative dislocation happened in 6 patients (5.6%). Female gender was a risk factor for lower IKDC (70.7 vs 78.1, P = 0.006), Tegner (5.1 vs 6.0, P = 0.006) and Kujala (88.2 vs 96.6, P = 0.008). Age (p = 0.011) and trochlear dysplasia (p = 0.016) were considered to be two failure factors for MPFL combined with TTO and LRR.

CONCLUSION

As a surgical method, MPFL combined with TTO and LRR would be a reliable choice with a low failure rate (5.6%). Female gender was a risk factor for worse postoperative outcomes. Preoperative failure risk factors in this study were age and trochlear dysplasia.

LEVEL OF EVIDENCE

Level IV; Case series.

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.

Ultrasonographic assessment of quadriceps and patellar tendon thicknesses in patients with patellofemoral pain syndrome

Objective

The aim of this study was to compare ultrasonographically measured quadriceps and patellar tendon thicknesses between Patellofemoral Pain Syndrome (PFPS) patients and age- and gender-matched healthy controls.

Methods

Among patients who presented to physical therapy and rehabilitation outpatient clinic in January–December 2016, 61 volunteers (28 men and 33 women; mean age: 30.79 ± 6.55 years) who were eligible considering the inclusion and exclusion criteria were enrolled. 30 were diagnosed with PFPS, and the remaining were age- and gender-matched healthy volunteers. Mean age was 30.03 ± 5.67 years in healthy subjects and 45.2% were of male gender. The patient group had mean age of 31.57 ± 7.37 years and 46.7% of the patients were male. Q angles were measured at standing, supine and sitting positions. Patellar and femoral tendon thicknesses and areas were measured ultrasonographically. Kujala questionnaire were used to evaluate the functional status of the participants.

Results

No significant difference was detected between groups regarding profession, educational background, and body mass indices (BMI) (p > 0.05). Q angle values were significantly higher in the patient group when compared to controls at standing (17.03 ± 3.84 vs. 13.87 ± 1.75°, p < 0.001), supine (16.20 ± 3.74 vs. 13.45 ± 1.79°, p = 0.001) and sitting (16.50 ± 3.28 vs. 13.71 ± 1.72°, p < 0.001) positions. Kujala score was significantly lower in the PFPS group when compared to controls (70.57 ± 8.37 vs. 98.58 ± 2.05, p < 0.001). Patellar (0.39 ± 0.08 vs. 0.32 ± 0.05 cm, p < 0.001) and quadriceps (0.64 ± 0.10 vs. 0.52 ± 0.09 cm, p < 0.001) tendon thicknesses were significantly higher in the PFPS group when compared to controls. There was no significant difference between groups regarding patellar tendon areas (p > 0.05). Patellar tendon thickness values of ≥0.35 cm were found to have 66.7% sensitivity and 67.7% specificity for PFPS diagnosis in the ROC curve analysis (area under curve: 0.771, 95% confidence interval: 0.655–0.887, p < 0.001). Quadriceps tendon thickness values of ≥0.54 cm were found to have 80% sensitivity and 71% specificity for PFPS diagnosis in the ROC curve analysis (area under curve: 0.824, 95% confidence interval: 0.710–0.939, p < 0.001). In PFPS patients, quadriceps tendon thickness had significant positive correlation with age (r = 0.405, p = 0.027) and BMI (r = 0.450, p = 0.013); and significant negative correlation with Kujala score (r = −0.441, p = 0.015). In the multivariate regression analysis, quadriceps tendon thickness was independently associated with the presence of PFPS (Exp (B): 3.089, 95% confidence interval: 1.344–7.100, p = 0.008).

Conclusion

Our study demonstrates that ultrasonographically measured patellar and quadriceps tendon thicknesses are significantly higher in subjects with PFPS and particularly, quadriceps tendon thickness may be used for the diagnosis.

Level of Evidence

Level III, Therapeutic Study.

Injuries of the adolescent girl athlete: a review of imaging findings

With the rising participation of girls in sports at both the recreational and elite levels, there has also been increased awareness of injuries common in this athlete population. Anatomic differences between boys and girls cause girl athletes to be predisposed to certain injuries. Certain behavioral patterns, such as eating disorders, also cause problems specific to girl athletes that may result in injury. Imaging plays a large role in diagnosis and ongoing management, but there has been only scant literature dedicated to the specific topic of imaging in girl athletes. The purpose of this article is to review the imaging findings and recommendations for injuries and other conditions affecting the adolescent girl athlete. This article first provides an overview of the key anatomic differences between boys and girls, including both static and dynamic factors, as well as non-anatomic differences, such as hormonal factors, and discusses how these differences contribute to the injury patterns that are seen more typically in girls. The article then reviews the imaging findings in injuries that are commonly seen in girl athletes. There is also a discussion of the "female athlete triad," which consists of osteoporosis, disordered eating, and amenorrhea, and the role of imaging in this condition.

Effects of Adding Single Joint Exercises to a Resistance Training Programme in Trained Women

BACKGROUND

The present study's aim was to compare the changes in muscle performance and anthropometric measures in trained women performing RT programs composed only of MJ exercises or programmes that involve the addition of SJ exercises.

METHODS

Seventeen trained women were randomised to MJ or MJ+SJ. Both groups performed the same MJ exercises following a nonlinear periodisation model for 8 weeks. The only difference was that the MJ+SJ group also performed SJ exercises. The participants were tested for 10 repetition maximum (10 RM), flexed arm circumference, and both biceps and triceps skinfold.

RESULTS

Both groups significantly increased 10 RM load for the bench press (12.6% MJ and 9.2% MJ+SJ), triceps (15.6% MJ and 17.9% MJ+SJ), pull down (9.8% MJ and 8.3% MJ+SJ), biceps (14.0% MJ and 13.0% MJ+SJ), leg press (15.2% MJ and 12.8% MJ+SJ) and knee extension (10.2% MJ and 9.1% MJ+SJ). The decreases in triceps (-5.1% MJ and -5.3% MJ+SJ) and biceps (-6.5% MJ and -5.7% MJ+SJ) skinfolds were also significant as were the increases in arm circumference (1.47% MJ and 1.58% MJ+SJ). In all tests there was nothing significantly different between groups.

CONCLUSIONS

The use of SJ exercises as a complement to a RT programme containing MJ exercises brings no additional benefit to trained women.

Combined Tibial Tubercle Osteotomy and Medial Patellofemoral Ligament Reconstruction for Recurrent Lateral Patellar Instability in Patients With Multiple Anatomic Risk Factors

PURPOSE

To report the outcomes for combined tibial tubercle osteotomy (TTO) and medial patellofemoral ligament (MPFL) reconstruction and assess for potential risk factors for recurrent instability and/or poor outcomes.

METHODS

The medical record at our institution was reviewed for patients treated with MPFL reconstruction and TTO for recurrent lateral patellar instability from 1998 to 2014. Preoperative imaging was assessed for trochlear dysplasia according to the Dejour classification (high grade = B, C, D) and the presence of patella alta using the Caton-Deschamps ratio (>1.2). The indication for combined MPFL reconstruction and TTO was MPFL insufficiency and a lateralized tibial tubercle. Outcomes were determined by recurrent instability, return to sport, and Kujala and International Knee Documentation Committee (IKDC) scores.

RESULTS

Thirty knees in 28 patients (14 M, 14 F) with a mean age of 22.6 ± 9.1 years (range, 13-51 years) were included with a mean follow-up of 48 ± 28 months (24-123 months). Seventy-three percent (22/30) had high-grade trochlear dysplasia, and 63% (19/30) had patella alta. One patient had a postoperative dislocation and 1 had a subluxation event. The Caton-Deschamps ratio decreased by a mean of 0.2 (P = .001), leaving 30% with postoperative patella alta. The mean postoperative scores were as follows: Tegner = 5 ± 2, Kujala = 89 ± 16 (45-100), and IKDC = 85 ± 17 (44-100). Eighty-three percent (15/18) returned to their preoperative sport. Female gender was a risk factor for lower IKDC (77.3 vs. 92.6, P = .01) and Kujala (82.2 vs. 95.0, P = .03) scores. Medialization greater than 10 mm was directly correlated to lower IKDC (P = .02) and Kujala (P = .01) scores.

CONCLUSIONS

The combination of MPFL reconstruction and TTO in patients with trochlear dysplasia results in low recurrence of instability. Patients on average had good subjective outcomes and were able to return to sport. Female gender and tibial tubercle medialization greater than 10 mm were associated with worse outcomes.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

A novel clinical test for assessing patellar cartilage changes and its correlation with magnetic resonance imaging and arthroscopy

Controversy still exists regarding the best clinical assessment test for chondromalacia patellae (CMP). Our study aims to evaluate the specificity and sensitivity of a novel clinical test for CMP, the "Patella Slide Test" (PST) against the findings of magnetic resonance imaging (MRI) and arthroscopy. We included 221 consecutive patients planned for elective knee arthroscopic surgery. An MRI scan of the symptomatic knee was performed prior to surgery. On the day of surgery, each patient was examined using the PST followed by a knee arthroscopy to assess the quality of the chondral surfaces of the patellofemoral joint. The MRI and PST results were compared against the arthroscopic findings that served as the gold standard. The PST (0.89) was statistically more sensitive than MRI (0.67) in diagnosing CMP. The PST (0.89) also had a greater negative predictive value (NPV) than MRI (0.74). However, MRI (0.94) was more specific than the PST (0.85). The differences in accuracy and positive predictive value of the PST versus MRI were not statically significant. In conclusion, the PST shows high sensitivity and has a greater NPV than MRI as a clinical test for diagnosing CMP.

Predicting muscle forces during the propulsion phase of single leg triple hop test

Functional biomechanical tests allow the assessment of musculoskeletal system impairments in a simple way. Muscle force synergies associated with movement can provide additional information for diagnosis. However, such forces cannot be directly measured noninvasively. This study aims to estimate muscle activations and forces exerted during the preparation phase of the single leg triple hop test. Two different approaches were tested: static optimization (SO) and computed muscle control (CMC). As an indirect validation, model-estimated muscle activations were compared with surface electromyography (EMG) of selected hip and thigh muscles. Ten physically healthy active women performed a series of jumps, and ground reaction forces, kinematics and EMG data were recorded. An existing OpenSim model with 92 musculotendon actuators was used to estimate muscle forces. Reflective markers data were processed using the OpenSim Inverse Kinematics tool. Residual Reduction Algorithm (RRA) was applied recursively before running the SO and CMC. For both, the same adjusted kinematics were used as inputs. Both approaches presented similar residuals amplitudes. SO showed a closer agreement between the estimated activations and the EMGs of some muscles. Due to inherent EMG methodological limitations, the superiority of SO in relation to CMC can be only hypothesized. It should be confirmed by conducting further studies comparing joint contact forces. The workflow presented in this study can be used to estimate muscle forces during the preparation phase of the single leg triple hop test and allows investigating muscle activation and coordination.

Effectiveness of the kinesiotaping in the patellofemoral pain syndrome

Objectives

This study aims to evaluate the effect of kinesiotaping implementation on pain and functional status in patellofemoral pain syndrome (PFPS).

Patients and methods

Between January 2014 and July 2014, this prospective, single-center, randomized-controlled study included a total of 75 knees from 43 patients (20 males, 23 females; mean age 33.8±7.9 years; range, 20 to 50 years). All patients were divided into three treatment groups: Group 1 (25 knees) were treated with kinesiotaping and exercise, Group 2 (25 knees) were treated with sham taping + and exercise, and Group 3 (25 knees) were treated with exercise alone. The Visual Analog Scale (VAS) was used to assess the pain severity. The Kujala Patellofemoral Scale (KPS) was used to determine the effect of the knee pain on the patients' daily living activities. All three groups were given the same exercise program during six weeks. Kinesiotaping was applied twice a week, 12 times in total during the treatment period of six weeks. The VAS and KPS assessments for all patients were made at baseline, then at the end of the treatment (week 6) and at week 12 the end of the 12th week.

Results

There were no statistically significant differences between the three groups in terms of age, sex, height, weight, and Body Mass Index (p>0.05, for all). A statistically significant improvement was observed in all groups in terms of the mean VAS and KPS scores before the treatment, at week 6, and at week 12 (p<0.001, for all). There was no statistically significant change in the mean changes of the VAS and KPS among the groups at week 6 and 12.

Conclusion

Our study results suggest that the addition of the kinesiotaping application to the exercise treatment for PFPS seems to be ineffective on pain control and improved daily life activities.

Patellofemoral Kinematics and Tibial Tuberosity-Trochlear Groove Distances in Female Adolescents With Patellofemoral Pain

BACKGROUND

Patellofemoral pain (PFP) is a prevalent disorder among female adolescents. Overuse is frequently cited as the cause of pain for this population. What is currently unclear, however, is if the patella demonstrates abnormal tracking patterns relative to the femoral trochlear groove in female adolescents with PFP.

PURPOSE

The aim of this case-control study was to determine if abnormal patellar tracking patterns are present in female adolescents with PFP. The secondary aim was to identify if an increased tibial tuberosity-trochlear groove (TT-TG) distance is associated with the observed kinematic patterns.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty female adolescent knees from 12 patients with PFP and 20 age-matched female knees from 13 healthy controls were recruited for this study. Patellofemoral kinematics (eg, lateral patellar displacement) during a repetitive knee extension-flexion maneuver was quantified by dynamic cine phase-contrast magnetic resonance imaging (MRI). Static MRI scans were used to determine the TT-TG distance.

RESULTS

Relative to the control cohort, female adolescents with PFP demonstrated significantly greater lateral displacement at 10° (3.2 mm; P < .001), 20° (2.3 mm; P < .001), and 30° (1.7 mm; P = .014) of knee flexion. A subgroup within this cohort (7 knees from 5 patients) demonstrated extreme lateral maltracking >2 SDs of the mean of the control cohort. This subgroup also demonstrated a greater TT-TG distance relative to the controls (Δ = 4.2 mm; P = .001).

CONCLUSION

This study demonstrates abnormal lateral patellar displacement in the absence of patellar tilt in female adolescents with PFP. Because all adolescents from both cohorts participated in impact sports, it appears that rigorous athletic training alone is inadequate to produce symptoms in this population. Rather, PFP may derive from a combination of physical activity in the context of pathological kinematics.

CLINICAL RELEVANCE

Abnormal patellar tracking patterns and abnormal static alignment have been shown to contribute to the etiology of patellofemoral pain in adults. This study demonstrates that pathologic patellar tracking patterns are present in adolescent females with patellofemoral pain.

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.

Correlation between Foot Arch Index and the Intensity of Foot, Knee, and Lower Back Pain among Pregnant Women in a South-Eastern Nigerian Community

OBJECTIVES

The aim of this study was to assess the arch height index of pregnant women and its correlation with foot pain, anterior knee pain, and lower back pain.

SUBJECTS AND METHODS

Two hundred and fifteen consenting pregnant women participated in this cross-sectional study. The arch height index was assessed from their foot prints, while pain intensity was rated on a numerical rating scale. Data were summarized with descriptive statistics and the Pearson correlation was used to determine correlations between the variables at p < 0.05.

RESULTS

Of the 215 pregnant women, 123 (57.2%) and 127 (59.9%) had low arch heights on the right and left feet, respectively, and the mean arch height indices were 0.27 ± 0.71 for the right foot and 0.28 ± 0.07 for the left foot. The prevalence of foot, knee, and lower back pain was 65 (30.2%), 43 (20.0%), and 93 (43.3%), respectively. The Pearson correlation analysis did not reveal any significant relationship (p > 0.05) between foot pain and each of the right (r = -0.010, p = 0.886) and left (r = 0.004, p = 0.955) arch indices as well as between knee pain and each of the right (r = 0.042, p = 0.536) and left (r = 0.045, p = 0.515) arch indices. A similar trend was observed for the lower back, which also did not show any significant relationship to each of the right (r = 0.026, p = 0.703) and left (r = 0.097, p = 0.157) arch indices.

CONCLUSION

The study participants had a high prevalence of low foot arches, indicating pes planus. Lower back pain was more common than foot and knee pain. The foot arch heights did not show any relationships between the intensities of foot, anterior knee, and lower back pain.

Common injuries and ailments of the female athlete; pathophysiology, treatment and prevention

With increasing numbers of women competing in high school and collegiate athletics, it is important that physicians become familiar with injury patterns and medical conditions unique to the female athlete. Observations and clinical data have elucidated unique biomechanical, anatomic and hormonal factors that predispose skeletally mature female athletes to anterior cruciate ligament (ACL) injuries, patellofemoral disorders and lower extremity stress fractures. Additionally, younger female athletes are particularly at risk of developing components of the "Female Athlete Triad" (more recently included under the syndrome of "Relative Energy Deficiency in Sport" [RED-S]): disordered eating, amenorrhea and osteoporosis. An understanding of the pathophysiology of these conditions has led to the development of programs that can treat their underlying causes, decrease susceptibility to injury, and improve the long-term health of the female athlete. This paper is intended to provide physicians with a review of the sex-specific etiology, prevention and treatment of injuries common to the female athlete.

New aetiology of patellofemoral pain syndrome

We report the case of a 30-year-old man with more than 100 different male sexual partners per year. He reported using cocaine, ecstasy, γ-hydroxybutyric acid and crystal mephedrone and presented with bilateral gonalgia resistant to standard analgesia. He had no noteworthy medical history, and physical examination and laboratory tests were uninformative. MRI showed marked intra-articular effusion but no meniscus or ligament damage. The aetiological diagnosis in this case was made by excluding other potential causes. Patellofemoral pain syndrome (PFPS) is one of the most common and challenging injuries. In this first case reported, the aetiology was found to be mechanical, due to the position adopted during fellatio with multiple male partners.

Knee joint kinetics in relation to commonly prescribed squat loads and depths

Controversy exists regarding the safety and performance benefits of performing the squat exercise to depths beyond 90° of knee flexion. Our aim was to compare the net peak external knee flexion moments (pEKFM) experienced over typical ranges of squat loads and depths. Sixteen recreationally trained men (n = 16; age, 22.7 ± 1.1 years; body mass, 85.4 ± 2.1 kg; height, 177.6 ± 0.96 cm; mean ± SEM) with no previous lower-limb surgeries or other orthopedic issues and at least 1 year of consistent resistance training experience while using the squat exercise performed single-repetition squat trials in a random order at squat depths of above parallel, parallel, and below parallel. Less than 1 week before testing, 1RM values were found for each squat depth. Subsequent testing required the subjects to perform squats at the 3 depths with 3 different loads: unloaded, 50% 1RM, and 85% 1RM (9 total trials). Force platform and kinematic data were collected to calculate pEKFM. To assess the differences among loads and depths, a 2-factor (load and depth) repeated measures analysis of variance with significance set at the p < 0.05 level was used. Squat 1RM significantly decreased 13.6% from the above-parallel to the parallel squat and another 3.6% from the parallel to the below-parallel squat (p < 0.05). Net peak external knee flexion moments significantly increased as both squat depth and load were increased (p ≤ 0.02). Slopes of pEKFM were greater from unloaded to 50% 1RM than when progressing from 50% to 85% 1RM (p < 0.001). The results suggest that typical decreases in squat loads used with increasing depths are not enough to offset increases in pEKFM.

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.

A review of the management of patellofemoral pain syndrome

OBJECTIVE

Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS.

METHODS

Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years.

RESULTS

Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS.

CONCLUSION

A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS.

Mobile-bearing total knee arthroplasty: a full traumatic rotation of 180°

From February 2008 to September 2012 we implanted 204 mobile-bearing knee prostheses in 192 patients. All the prostheses were cemented (both femoral and tibial components), and the patella was not replaced. Only one early complication of the implants (1/204 = 0.004%) occurred after a traumatic event as a full 180° rotation of the mobile-bearing polyethylene insert. A 78-year-old woman presented with swelling and severe pain at her right knee. This traumatic event was the only case among our mobile-bearing insert patients. 
The failed polyethylene inserts were retrieved and studied using a scanning electron microscope (SEM, ZEISS EVO 50 EP, Cambridge, UK) operating at 20 kV. 
Scratching and pitting were found on the UHMWPE insert perpendicular to the machining tracks for the concave surface. SEM micrographs of the insert showed burnishing on the concave surfaces and longitudinal scratches were clearly detectable and well-marked on the analyzed surfaces. 
A traumatic, fully rotating, polyethylene insert is rare and our case is the first report describing a traumatic event with a complete 180 degree rotation mobile-bearing in a total knee prosthesis. 
In the literature few reports discuss clinical outcomes after total knee arthroplasty in patients with Parkinson's disease and they cite mixed results. However, some authors suggest that posterior-stabilized and cruciate-retaining TKA should work well while others prefer cruciate-retaining, condylar constrained kinetics, or hinged devices. Although we did not implant a posterior-stabilized mobile-bearing total knee prosthesis or a constrained prosthesis, we obtained good clinical and radiological results at the 2-year followup.

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.

The effects of movement pattern modification on lower extremity kinematics and pain in women with patellofemoral pain

STUDY DESIGN

Controlled laboratory study.

OBJECTIVES

To compare hip and knee kinematics and pain during a single-limb squat between 3 movement conditions (usual, exaggerated dynamic knee valgus, corrected dynamic knee valgus) in women with patellofemoral pain.

BACKGROUND

Altered kinematics (increased hip adduction, hip medial rotation, knee abduction, and knee lateral rotation, collectively termed dynamic knee valgus) have been proposed to contribute to patellofemoral pain; however, cross-sectional study designs prevent interpreting a causal link between kinematics and pain.

METHODS

The study sample included 20 women with patellofemoral pain, who demonstrated observable dynamic knee valgus. Participants performed single-limb squats under usual, exaggerated, and corrected movement conditions. Pain during each condition was assessed using a 0-to-100-mm visual analog scale. Hip and knee frontal and transverse plane angles at peak knee flexion and pain levels were compared using repeated-measures 1-way analyses of variance. Pearson correlation coefficients were used to determine within-condition associations between kinematic variables and pain.

RESULTS

In the exaggerated compared to the usual condition, increases were detected in hip medial rotation (mean ± SD difference, 5.8° ± 3.2°; P<.001), knee lateral rotation (5.5° ± 4.9°, P<.001), and pain (8.5 ± 10.8 mm, P = .007). In the corrected compared to the usual condition, decreases were detected in hip adduction (mean ± SD difference, 3.5° ± 3.7°; P = .001) and knee lateral rotation (1.6° ± 2.8°, P = .06); however, average pain was not decreased (1.2 ± 14.8 mm, P = 1.0). Pain was correlated with knee lateral rotation in the usual (r = -0.47, P = .04) and exaggerated (r = -0.49, P = .03) conditions. In the corrected condition, pain was correlated with hip medial rotation (r = 0.44, P = .05) and knee adduction (r = 0.52, P = .02).

CONCLUSION

Avoiding dynamic knee valgus may be an important component of rehabilitation programs in women with patellofemoral pain, as this movement pattern is associated with increased pain.

Kinetic chains: a review of the concept and its clinical applications

During the past decade, our understanding of biomechanics and its importance in rehabilitation has advanced significantly. The kinetic chain, a concept borrowed from engineering, has helped us better understand the underlying physiology of human movement. This understanding, in turn, has facilitated the development of new and more rational rehabilitation strategies. The kinetic chain concept has application in a wide spectrum of clinical conditions, including musculoskeletal medicine, sports medicine, and neurorehabilitation, as well as prosthetics and orthotics. The purpose of this review is to provide insights into the biomechanics related to the concept of kinetic chains, with a specific focus on closed kinetic chains and its clinical applications in rehabilitation.

Association of flat feet with knee pain and cartilage damage in older adults

OBJECTIVE

To assess the cross-sectional relation of planus foot morphology to ipsilateral knee pain and compartment-specific knee cartilage damage in older adults.

METHODS

In the Framingham Studies, we adapted the Staheli Arch Index (SAI) to quantify standing foot morphology from pedobarographic recordings. We inquired about knee pain and read 1.5 T magnetic resonance image (MRI) scans using the Whole-Organ MRI Score. Logistic regression compared the odds of knee pain among the most planus feet to the odds among all other feet, and estimated odds within categories of increasing SAI. Similar methods estimated the odds of cartilage damage in each knee compartment. Generalized estimating equations adjusted for age, sex, body mass index, and nonindependent observations.

RESULTS

Among 1,903 participants (56% women, mean ± SD age 65 ± 9 years), 22% of knees were painful most days. Cartilage damage was identified in 45% of medial tibiofemoral (TF), 27% of lateral TF, 58% of medial patellofemoral (PF), and 42% of lateral PF compartments. Compared with other feet, the most planus feet had 1.3 times (95% confidence interval [95% CI] 1.1-1.6) the odds of knee pain (P = 0.009), and 1.4 times (95% CI 1.1-1.8) the odds of medial TF cartilage damage (P = 0.002). Odds of pain (P for linear trend = 0.05) and medial TF cartilage damage (P for linear trend = 0.001) increased linearly across categories of increasing SAI. There was no association between foot morphology and cartilage damage in other knee compartments.

CONCLUSION

Planus foot morphology is associated with frequent knee pain and medial TF cartilage damage in older adults.

Analysis of the center of pressure displacement, ground reaction force and muscular activity during step exercises

Anterior Knee Pain (AKP) is considered as one of the most common, yet misunderstood, knee pathologies. The aim of this study was to evaluate the displacement area of the center of pressure, Ground Reaction Force (GRF), and the electromyography activity of the hip and the quadriceps muscles in healthy and AKP individuals during the step-up and step-down exercises. Both groups (Control group and AKP group) were composed of 15 volunteers submitted to the exercises on a force plate. The AKP group presented greater displacement area of the center of pressure for all the situations evaluated than the Control group (p<0.05), as well as a lesser magnitude of the GRF during the step-down exercise. The AKP group presented lower electromyography activity than the Control group in all situations evaluated. AKP individuals do not have muscle imbalances; they present a lower electromyography activity of the stabilizing muscles of the patella and hip and show greater instability in activities such as step up and down compared to normal subjects.

Hip strengthening prior to functional exercises reduces pain sooner than quadriceps strengthening in females with patellofemoral pain syndrome: a randomized clinical trial

STUDY DESIGN

Randomized clinical trial.

OBJECTIVES

To determine if females with patellofemoral pain syndrome (PFPS) who perform hip strengthening prior to functional exercises demonstrate greater improvements than females who perform quadriceps strengthening prior to the same functional exercises.

BACKGROUND

Although PFPS has previously been attributed to quadriceps dysfunction, more recent research has linked this condition to impairment of the hip musculature. Lower extremity strengthening has been deemed an effective intervention. However, research has often examined weight-bearing exercises, making it unclear if increased strength in the hip, quadriceps, or both is beneficial.

METHODS

Thirty-three females with PFPS performed either initial hip strengthening (hip group) or initial quadriceps strengthening (quad group) for 4 weeks, prior to 4 weeks of a similar program of functional weight-bearing exercises. Self-reported pain, function, and functional strength were measured. Isometric strength was assessed for hip abductors, external rotators, and knee extensors. A mixed-model analysis of variance was used to determine group differences over time.

RESULTS

After 4 weeks, there was less mean ± SD pain in the hip group (2.4 ± 2.0) than in the quad group (4.1 ± 2.5) (P = .035). From baseline to 8 weeks, the hip group demonstrated a 21% increase (P<.001) in hip abductor strength, while that remained unchanged in the quad group. All participants demonstrated improved subjective function (P<.006), objective function (P<.001), and hip external rotator strength (P = .004) from baseline to testing at 8 weeks.

CONCLUSION

Both rehabilitation approaches improved function and reduced pain. For patients with PFPS, initial hip strengthening may allow an earlier dissipation of pain than exercises focused on the quadriceps.

The female athlete

Over time, women have become more extensively involved in athletic programs. The female athlete presents a unique challenge to sports medicine in general. Although specific types of injuries are the same as in the male athlete, the female athlete is at higher risk for some of these injuries. Injuries may be sport specific, but gender-related injuries are also related to morphologic and physiologic differences between the male and female athlete. This article reviews some of the differences between the male and female athlete and focuses on a few prominent injuries or risks related specifically to the woman athlete.

Do females with patellofemoral pain have abnormal hip and knee kinematics during gait?

Our objective was to test the hypothesis that females with patellofemoral pain (PFP) have increased hip adduction, hip medial rotation, and knee valgus (medial collapse) during the stance phase of gait. Twenty subjects with PFP and 20 pain-free subjects participated. Subjects underwent three-dimensional motion analysis during free speed and fast speed walking. Hip frontal and transverse plane angles and knee frontal plane angles were calculated at two time points (peak knee extensor moment [PkMOM], and maximum knee extension/hyperextension angle [MxExt]) and averaged over three trials. Within each walking task, Student's t-tests compared group differences in all variables. A post hoc analysis was performed, which compared a subgroup of four PFP subjects (those whose pain level was above 30/100) to pain-free subjects. Initially, there were no group differences during free speed walking. During fast speed walking, subjects with PFP had less hip adduction at PkMOM and greater hip adduction at MxExt. The subgroup of PFP subjects had greater hip adduction at PkMOM and greater knee valgus at MxExt during free speed walking and greater hip adduction and knee valgus at MxExt during fast speed walking. During low-level tasks, frontal plane components of medial collapse were present at the hip and knee in a subgroup of PFP subjects with higher pain levels. Symptom behavior may be important in identifying individuals with medial collapse movement impairments.

A 5° medial wedge reduces frontal but not saggital plane motion during jump landing in highly trained women athletes

Lower extremity mechanics during landing have been linked to traumatic and nontraumatic knee injuries, particularly in women’s athletics. The effects of efforts to mitigate these risks have not been fully elucidated. We previously reported that a 5° medial wedge reduced ankle eversion and knee valgus. In the present report we further investigated the effect of a 5° medial wedge inserted in the shoes of female athletes on frontal plane hip motion, as well as ankle, knee, hip, and trunk saggital plane motion during a jump landing task. Kinematic data were obtained from 10 intercollegiate female athletes during jump landings from a 31 cm platform with and without a 5° medial wedge. Hip adduction was reduced 1.98° (95% CI 0.97–2.99°) by the medial wedge but saggital plane motions were unaffected. A 5° medial wedge reduces frontal plane motion and takes the knee away from a position associated with anterior cruciate ligament injury and patellofemoral pain syndrome. Although frontal plane motion was not captured it is unlikely to have increased in a bilateral landing task. Thus, it is likely that greater muscle forces were generated in these highly trained athletes to dissipate ground reaction forces when a medial wedge was in place. Additional investigation in younger and lesser trained athletes is warranted to assess the impact of orthotic devices on knee joint mechanics.