Patellofemoral pain syndrome: evaluation of location and intensity of pain

Patellofemoral pain over time: Protocol for a prospective, longitudinal study investigating physical and non-physical features

Background

This is a protocol for a prospective longitudinal study that aims to investigate: (1) group-by-time changes over a minimum of 15 months follow-up in patellofemoral pain (PFP) symptoms, biomechanical, muscle function, pain processing, and psychological features; (2) the extent to which changes in biomechanical, muscle function, pain processing, and psychological features are associated with changes in self-reported pain, physical performance measures, self-reported function, health-related quality of life (HRQOL), and physical activity level.

Methods

Individuals with PFP (n = 144) and control individuals (n = 85) without PFP were assessed at baseline. Outcomes assessed included: 3D kinematics and kinetics during single leg squat, step-down and single leg hop; maximal torque and rate of torque development of hip abductors and knee extensors/flexors; force steadiness of hip abductors and knee extensors; anterior and lateral trunk endurance; pressure pain thresholds at the center of patella and contralateral shoulder; kinesiophobia (Tampa Scale for Kinesiophobia); pain catastrophizing (Pain Catastrophizing Scale); worst self-reported pain (Visual Analogue Scale); physical performance measures (Single Leg Hop Test and Forward Step-Down Test); self-reported function (Anterior Knee Pain Scale); HRQOL (Medical Outcome Short-Form 36), and physical activity level (Baecke's Questionnaire). Follow-up assessments will be identical to the baseline and will be performed after a minimum of 15 months. Generalized linear mixed model (GLMM) will be used to investigate group-by-time differences. Linear regression models will be used to determine the extent to which changes in biomechanical, muscle function, pain processing, and psychological features are associated with changes in self-reported pain, physical performance measures, self-reported function, HRQOL, and physical activity level.

Discussion

Physical and non-physical features have been previously associated with PFP. However, the present study will be the first to investigate their integrated evolution as part of the natural history of PFP and its progression. In doing so, we will be able to determine their behavior in the long-term, as well as how they prospectively associate with each other and with clinical outcomes. Ultimately, this will provide a greater understanding of predictors of long-term outcome and possible targets for interventions.

Load-deformation characteristics of cadaver patellae: Relationship to intraosseous pressure

BACKGROUND

Anterior knee pain can arise from several sources. One of the main sources of pain in patients with anterior knee pain is the patella. Increased patellofemoral joint loading is the prime source of patellar pain. Elevated intraosseous pressures have been measured in painful patellae and increasing the intraosseous fluid pressure in the patella causes pain. Whether elevated fluid pressure is an independent source of pain or if the patellar deformation under load leads to elevated pressure and pain has not been determined. Our hypothesis was that the patella deforms measurably under physiologic loads and that intraosseous pressure increase is related to that deformation. The relationship may be linear as measured by correlation or nonlinear as measured by the sum of squared error.

METHODS

Part I: Assessment of patellar load-deformation profiles were obtained in 2 intact cadaver patellae and 1 bisected patella under physiologic loads. Part II: Measurements of intraosseous pressure were obtained in 9 cadaver patellae as the patellae were compressed with physiologic loads. Pressures were recorded at sequential levels of anterior-posterior patellar compression.

FINDINGS

Cadaver patellae compress up to 3.5 mm in the anterior-posterior plane. Compression with physiologic forces raises intraosseous pressure to more than 40 mmHg.

INTERPRETATION

Load-deformation of cadaver patellae results in deformation and an increase in intraosseous pressure. These findings may help explain previous studies of patellofemoral pain where elevated patellar intraosseous pressures have been found in vivo.

Current Evidence Does Support the Use of KT to Treat Chronic Knee Pain in Short Term: A Systematic Review and Meta-Analysis

Objective

To demonstrate whether KT is better than placebo taping, nonelastic taping, or no taping in reducing pain.

Methods

PubMed, Embase, Web of Science, the Cochrane Central Library, and ClinicalTrials.gov were systematically searched up to 20 October 2020 for randomized controlled studies that used KT to treat chronic knee pain according to PRISMA guidelines. We extracted the mean differences and SD in pretreatment and posttreatment for selected outcomes measured in the experimental and control groups for subsequent meta-analyses.

Results

In total, 8 studies involving 416 participants fulfilled the inclusion criteria. Our results indicated that KT is better than other tapings (placebo taping or nonelastic taping) in the early four weeks. The mean difference was −1.44 (95% CI: −2.04–−0.84, I² = 49%, P ≤ 0.01). Treatment methods which were performed for more than six weeks (0.16 (95% CI: −0.35–0.68, I² = 0%, P=0.53)) show no significant difference in reducing pain. In studies in which visual analogue scale was measured, a positive effect was observed for KT combined with exercise program training (−3.27 (95% CI: −3.69–2.85, I² = 0%, P < 0.05)).

Conclusion

KT exhibited significant but temporary pain reduction.

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.

Patellar bone strain after total knee arthroplasty is correlated with bone mineral density and body mass index

Patella-related complications after total knee arthroplasty (TKA) remain a major clinical concern. Previous studies have suggested that increased postoperative patellar bone strain could be related to such complications, but there is limited knowledge on patellar strain after TKA. The objective of this study was to predict patellar bone strain after TKA and evaluate correlations with various preoperative data. Fourteen TKA patients with a minimum follow-up of one year were included in this study. Using preoperative CT datasets, preoperative planning, and postoperative X-rays, a method is presented to generate patient-specific finite element models after virtual TKA. Patellar kinematics and forces were predicted during a squat movement, and patellar bone strain was evaluated at 60° of knee flexion. Strain varied greatly among patients, but was strongly negatively correlated (r = -0.85, p < 0.001) with bone mineral density (BMD) and moderately positively (r  = 0.54, p  =  0.05) with body mass index (BMI). The BMI/BMD ratio explained 87% of strain, and should be further investigated as a potential risk factor for clinical complications. This study represents a preliminary step towards the identification of patients at risk of patellar complications after TKA.

Is there a correlation in frontal plane knee kinematics between running and performing a single leg squat in runners with patellofemoral pain syndrome and asymptomatic runners?

BACKGROUND

Knee kinematics when running, specifically knee valgus, have been linked to patellofemoral pain syndrome. Assessing running biomechanics requires skill, equipment and time. Clinically, the single leg squat is used to make inferences about knee kinematics during running. No evidence supports this practice.

METHODS

Sixteen asymptomatic runners and sixteen runners with patellofemoral pain syndrome were recruited. Asymptomatic runners were sub-divided by dominant and non-dominant leg and runners with patellofemoral pain syndrome by painful and non-painful leg. This gave four groups. Participants were videoed performing single leg squats and running on a treadmill. Frontal plane knee kinematics were calculated using the frontal plane projection angle. Correlation in frontal plane projection angle between running and single leg squat were calculated using Pearson's correlation coefficient. Differences in frontal plane projection angle between groups for running and single leg squat were calculated using multiple independent t-tests with Bonferroni correction.

FINDINGS

Correlation in frontal plane projection angle between running and the single leg squat was not statistically significant for the painful leg group (p = 0.19) but was for the remaining groups (p < 0.05). There was no statistically significant difference in frontal plane projection angle between the four groups when running. Single leg squat frontal plane projection angle was significantly larger for the painful leg group (10.3°) than the dominant leg (-0.2° (p = 0.003)) and non-dominant leg (-0.4° (p = 0.004)) in the asymptomatic runners group.

INTERPRETATION

The single leg squat cannot be used to make inferences about frontal plane knee kinematics in running gait in patellofemoral pain syndrome sufferers.

Effectiveness of Foot Biomechanical Orthoses to Relieve Patients' Knee Pain: Changes in Neural Strategy After 9 Weeks of Treatment

Knee pain is one of the most common lower leg complaints. It is often treated with plantar orthoses to provide cushioning and correct locomotion, imbalances of the foot, and postural deficits. However, the published scientific data are poor concerning the mechanisms involved in pain reduction after wearing foot orthoses, and, to the best of our knowledge, no trial has investigated the mid-term effectiveness. The aim of the present study was to evaluate the effectiveness of foot orthoses according to sound biomechanical principles in the treatment of knee pain. Attention was mainly focused on changes in the central control strategies. Fifteen subjects were included in the protocol. The patients with knee pain were compared with healthy participants (control group) exhibiting no knee pain. In the patients with knee pain, pain perception, dynamic analysis of the gait, stabilometry, the soleus Hoffmann reflex at rest and during voluntary contraction, and V-wave were measured before and 3, 6, and 9 weeks after wearing orthoses. In the control group (n = 5), the same parameters were recorded at 0, 3, 6, and 9 weeks, but the subjects had not worn orthoses. In the patient group (n = 10), the results indicated that pain had significantly decreased from the third week onward, although the parameters of gait and stabilometry remained unchanged. From the sixth week, the soleus Hoffmann reflex during voluntary contraction wave was significantly reduced, suggesting an increase in motoneuronal presynaptic inhibition by non-nociceptive afferents. The V-wave amplitude increased throughout the 9 weeks of the experiment, suggesting a progressive increase in corticospinal and/or extrapyramidal descending pathway inputs, probably due to pain reduction. In the control group, no change was observed throughout the experimental sessions. Our data indicated that foot orthoses relieved patients' knee pain and reduced the descending motor inhibition. Changes in spinal modulation could contribute to a better quality of life. However, this treatment failed to change the altered gait, despite changes in spinal and supraspinal modulation.

[A comparative study on effectiveness of patellar resurfacing against non-resurfacing in total knee arthroplasty]

Objective

To investigate the effectiveness of total knee arthroplasty (TKA) with or without patellar resurfacing.

Methods

Between March 2013 and August 2015, 30 patients (60 knees) with osteoarthritis who met the inclusion criteria were recruited in the study. Of 30 cases, 24 were male and 6 were female with an average age of 57.2 years (range, 37-65 years). The body mass index ranged from 19.5 to 40.3 kg/m ² (mean, 28.2 kg/m ²). According to Kellgren-Lawrence grading, there were 8 cases at grand Ⅲ and 22 cases at grand Ⅳ. All patients underwent primary bilateral TKA. The patellar resurfacing was done at the unilateral knee randomly (resurfacing side); the opposite treatment was done at the other side (non-resurfacing side). The indexes of 2 groups were recorded and compared, including the intraoperative blood loss, operation time, knee society score (KSS), "Forgotten Joint" scale (FJS), anterior knee pain, anterior patellar spirant, knee constraint feeling, anterior patellar clunk, muscle power of knee extension, and ability of up and down stairs, weight-bearing flexion, squatting down, cross-legged, knee down, knee extension, and patient satisfaction. Radiographic examination was used to analyze the prosthesis position.

Results

The operation time were (126±14) minutes and (112±11) minutes in resurfacing side and non-resurfacing side, respectively, showing significant difference between two sides ( t=5.103, P=0.030); and there was no significant difference in intraoperative blood loss between two sides ( t=3.431, P=0.800). All patients were followed up 2-4 years (mean, 2.6 years). There was no significant difference ( P>0.05) between two sides in KSS clinical and functional scores at preoperation and 6 weeks, 6 months, and 2 years after operation; in visual analogue scale (VAS) score of anterior knee pain at preoperation and 6 weeks after operation; in incidences of anterior patellar spirant, knee constraint feeling, anterior patellar clunk, and muscle power of knee extension at 6 weeks, 6 months, and 2 years after operation; in incidences of disability of up and down stairs, weight-bearing flexion, squatting down, cross-legged, knee down, and knee extension at 6 weeks, 6 months, and 2 years after operation; in ratio of FJS score at 2 years after operation. The VAS scores at 6 months and 2 years after operation in resurfacing group were significantly lower than those in non-resurfacing group ( Z=-1.997, P=0.046; Z=-2.197, P=0.028). Patient satisfaction of resurfacing side was superior to the non-resurfacing side at 6 weeks after operation ( χ²=4.271, P=0.039). Radiographic examination showed no prosthesis loosing occurred.

Conclusion

The effectiveness of TKA with patellar resurfacing is better than that with non-resurfacing in patients satisfaction.

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.

The immediate effect of patellar tendon strap on weight-bearing asymmetry during squatting in patients with unilateral knee osteoarthritis: A pilot study

BACKGROUND

Knee osteoarthritis has commonly been associated with a symptom of pain resulting in an inter-limb weight-bearing asymmetry during functional tasks. Patellar tendon strap is one of the non-pharmacologic interventions to alleviate knee pain.

OBJECTIVES

To investigate the immediate effect of a patellar tendon strap on weight-bearing asymmetry during squatting in people with unilateral knee osteoarthritis.

STUDY DESIGN

Cross-sectional study.

METHODS

Ten patients with unilateral knee osteoarthritis and 10 healthy subjects were included in the study. Weight-bearing asymmetry of patients was assessed using a weight-bearing squat test during squatting at 30° and 60° both with and without patellar tendon strap. Pain intensity was assessed during squatting in unstrapped and strapped conditions with Visual Analog Scale.

RESULTS

The decrease in weight-bearing asymmetry values immediately after wearing patellar tendon strap during 30° (p = 0.006) and 60° (p = 0.011) of squatting tests was significantly higher in knee osteoarthritis patients than in healthy subjects. Reported pain intensity was similar in unstrapped and strapped conditions (p = 0.066).

CONCLUSION

The results of this study showed improved inter-limb weight-bearing symmetry during squatting. Further research with larger sample sizes investigating the effect of patellar tendon strap on weight-bearing asymmetry during functional activities in people with knee osteoarthritis is warranted.

CLINICAL RELEVANCE

Patellar tendon straps (easily fit and cheap unlike knee braces) had more improvements in inter-limb weight-bearing symmetry during squatting in people with knee osteoarthritis compared to healthy subjects. This study is a new insight for future studies to investigate clinical benefits of wearing patellar tendon straps in this population.

Coronal patellar osteotomy of the external facet combined with the release of the lateral retinaculum improves the clinical outcomes of isolated lateral release in lateral knee compartment syndrome

OBJECTIVE

To describe a novel coronal osteotomy of the external facet of the patella, and to evaluate if the outcomes of the treatment of lateral knee compartment syndrome (LKCS) with this osteotomy, combined with the release of the external lateral retinaculum, are better than the isolated lateral retinacular release.

MATERIAL AND METHODS

A prospective study with a 2 year follow up that included 70 patients diagnosed with LKCS, distributed into 2 groups. The first group included 50 patients on whom the lateral retinacular release combined with osteotomy was performed, and a second group on whom an isolated retinacular release was performed. Measurements were made using the Werner functional scale before the surgery and at 3, 12, and 24 months follow-up.

RESULTS

There were significant differences in the overall functional state between the two groups after the surgery (better in the osteotomy group at all the intervals, P<.05). The improvement, which was progressive up to 12 months, was slightly less at 24 months, although the values were still better than the pre-surgical ones in both groups. Pain was the variable that showed most improvement. The patients with LKCS with degenerative signs showed a benefit in all cases.

CONCLUSION

The results demonstrate that the described patellar osteotomy technique, combined with lateral retinacular release, significantly improves the pain and the functional scale score of patients with LKCS after 2 years of follow-up, to a greater extent than isolated lateral retinacular release, including those in which there was evidence of degenerative signs.

Is there a role of pulsed electromagnetic fields in management of patellofemoral pain syndrome? Randomized controlled study at one year follow-up

Patellofemoral pain syndrome (PFPS) is a common cause of recurrent or chronic knee pain in young adults, generally located in the retropatellar region. Etiology is controversial and includes several factors, such as anatomical defects, muscular imbalance, or joint overuse. Good results have been reported with exercise therapy, including home exercise program (HEP). Joint inflammation with increase of pro-inflammatory cytokines levels in the synovial fluid might be seen especially when chondromalacia becomes evident. Biophysical stimulation with pulsed electromagnetic fields (PEMFs) has shown anti-inflammatory effects and anabolic chondrocyte activity. The purpose of this randomized controlled study was to evaluate if the combination of HEP with PEMFs was more effective than HEP alone in PFPS treatment. Thirty-one PFPS patients were enrolled in this study. All patients were instructed to train with HEP. Patients in the PEMFs group associated HEP with PEMFs. Function and pain were assessed with Victorian Institute of Sport Assessment score (VISA), Visual Analog Scale (VAS), and Feller's Patella Score at baseline at 2, 6, and 12 months of follow-up. Drug assumption was also recorded. Increase in VISA score was significantly higher in PEMFs group compared to controls at 6 and 12 months, as well as the increase in the Feller's Patella Score at 12 months. VAS score became significantly lower in the PEMFs group with respect to control group since 6 month follow-up. Pain reduction obtained with PEMFs enhanced practicing therapeutic exercises leading to a better recovery process; this is extremely important in addressing the expectations of young patients, who wish to return to sporting activities.

Static balance in patients with patellofemoral pain syndrome

Background:

The relationship between one-leg static standing balance (OLSSB) and patellofemoral pain syndrome (PFPS) is unknown.

Hypothesis:

OLSSB decreases in patients with PFPS.

Design:

Prospective case series.

Methods:

Fifty-two women with unilateral PFPS were enrolled in this study. OLSSB was evaluated with a stabilometer. Q angle was measured with a lengthened-arm universal goniometer. Lower extremity alignment was analyzed with full-length standing anteroposterior teleroentgenograms. Quadriceps and hamstring strength was measured on an isokinetic dynamometer.

Results:

There were significant differences in OLSSB, Q angle, and strength of quadriceps and hamstring between the symptomatic and asymptomatic sides. There was a correlation between the strength of the quadriceps and hamstring and OLSSB, while there was no correlation between OLSSB and the severity of pain, lower extremity alignment, and Q angle on the symptomatic side.

Conclusions:

OLSSB and quadriceps and hamstring strength decreased and Q angle increased on the symptomatic side in PFPS patients. A relationship between OLSSB and pain, Q angle, and lower extremity alignment was not detected, while there was a correlation between the strength of the quadriceps and hamstring and OLSSB.

Clinical Relevance:

A quadriceps and hamstring strengthening may be beneficial to improve OLSSB in patients with PFPS.

Patellofemoral pain: proximal, distal, and local factors, 2nd International Research Retreat

Patellofemoral pain (PFP) is one of the most common lower extremity conditions seen in orthopaedic practice. The mission of the second International Patellofemoral Pain Research Retreat was to bring together scientists and clinicians from around the world who are conducting research aimed at understanding the factors that contribute to the development and, consequently, the treatment of PFP. The format of the 2.5-day retreat included 2 keynote presentations, interspersed with 6 podium and 4 poster sessions. An important element of the retreat was the development of consensus statements that summarized the state of the research in each of the 4 presentation categories. In this supplement, you will find the consensus documents from the meeting, as well as the keynote addresses, schedule, and platform and poster presentation abstracts.

Combined single photon emission computerised tomography and conventional computerised tomography (SPECT/CT) in patellofemoral disorders: a clinical review

Patellofemoral disorders are common conditions seen in a knee clinic but can present a great diagnostic challenge to the orthopaedic surgeon. Combined single photon emission computerised tomography with conventional computer tomography (SPECT/CT) provides the clinician with precise anatomical and physiological information of the patellofemoral joint. We present a clinical review that highlights the value of SPECT/CT in patients with patellofemoral disorders, where other modalities such as radiographs, MRI, and conventional CT did not provide sufficient information. SPECT/CT has proven to be helpful for establishing the diagnosis and guidance for further treatment. SPECT/CT should be recognised as a valuable diagnostic tool in orthopaedic patients.

Surplus value of hip adduction in leg-press exercise in patients with patellofemoral pain syndrome: a randomized controlled trial

BACKGROUND

A common treatment for patients with patellofemoral pain syndrome (PFPS) is strength (force-generating capacity) training of the vastus medialis oblique muscle (VMO). Hip adduction in conjunction with knee extension is commonly used in clinical practice; however, evidence supporting the efficacy of this exercise is lacking.

OBJECTIVE

The objective of this study was to determine the surplus effect of hip adduction on the VMO.

DESIGN

This study was a randomized controlled trial.

SETTING

The study was conducted in a kinesiology laboratory.

PARTICIPANTS

Eighty-nine patients with PFPS participated.

INTERVENTION

Participants were randomly assigned to 1 of 3 groups: hip adduction combined with leg-press exercise (LPHA group), leg-press exercise only (LP group), or no exercise (control group). Training consisted of 3 weekly sessions for 8 weeks.

MEASUREMENTS

Ratings of worst pain as measured with a 100-mm visual analog scale (VAS-W), Lysholm scale scores, and measurements of VMO morphology (including cross-sectional area [CSA] and volume) were obtained before and after the intervention.

RESULTS

Significant improvements in VAS-W ratings, Lysholm scale scores, and VMO CSA and volume were observed after the intervention in both exercise groups, but not in the control group. Significantly greater improvements for VAS-W ratings, Lysholm scale scores, and VMO volume were apparent in the LP group compared with the control group. There were no differences between the LP and LPHA groups for any measures.

LIMITATIONS

Only the VMO was examined by ultrasonography. The resistance level for hip adduction and the length of intervention period may have been inadequate to induce a training effect.

CONCLUSIONS

Similar changes in pain reduction, functional improvement, and VMO hypertrophy were observed in both exercise groups. Incorporating hip adduction with leg-press exercise had no impact on outcome in patients with PFPS.

Responsiveness of the activities of daily living scale of the knee outcome survey and numeric pain rating scale in patients with patellofemoral pain

OBJECTIVE

To assess internal and external responsiveness of the Activity of Daily Living Scale of the Knee Outcome Survey and Numeric Pain Rating Scale on patients with patellofemoral pain.

DESIGN

One group pre-post design.

SUBJECTS

A total of 60 individuals with patellofemoral pain (33 women; mean age 29.9 (standard deviation 9.6) years).

METHODS

The Activity of Daily Living Scale and the Numeric Pain Rating Scale were assessed before and after 8 weeks of physical therapy program. Patients completed a global rating of change scale at the end of therapy. The standardized effect size, Guyatt responsiveness index, and the minimum clinical important difference were calculated.

RESULTS

Standardized effect size of the Activity of Daily Living Scale was 0.63, Guyatt responsiveness index was 1.4, area under the curve was 0.83 (95% confidence interval: 0.72, 0.94), and the minimum clinical important difference corresponded to an increase of 7.1 percentile points. Standardized effect size of the Numeric Pain Rating Scale was 0.72, Guyatt responsiveness index was 2.2, area under the curve was 0.80 (95% confidence interval: 0.70, 0.92), and the minimum clinical important difference corresponded to a decrease of 1.16 points.

CONCLUSION

Information from this study may be helpful to therapists when evaluating the effectiveness of rehabilitation intervention on physical function and pain, and to power future clinical trials on patients with patellofemoral pain.

Adolescent patellofemoral pain: implicating the medial patellofemoral ligament as the main pain generator

PURPOSE

The purpose of this study is to define the clinical presentation of adolescent patellofemoral pain.

METHODS

A review was completed of all patients with patellofemoral pain at a children's hospital sports clinic over a 3-year period.

RESULTS

One hundred and one patients (91 female) with 136 symptomatic knees were identified. Mean age was 14.4 years. Knee pain was localized to the anteromedial or anterior region of the knee in 96% of patients and was typically produced with running (94%), jumping (92%) and stair use (69%). On physical examination there was usually a non antalgic gait (99%), no patellofemoral crepitation (98%), normal lower extremity angular (84%) and rotational alignment (94%), with no foot malalignment (>97%). The medial patellofemoral ligament (MPFL) was the most palpably tender area of the knee in 98% of patients. During "lateral apprehension" testing, 89% had pain at the MPFL, but not true apprehension. A "J-sign" was present at terminal knee extension in 65%. Mean Q-angle was 18.7 degrees . Means of all radiographic measures were within normal ranges.

CONCLUSION

The prototypical patient had anterior/anteromedial knee pain of insidious onset during running and jumping. The most consistent physical findings were focal tenderness at the MPFL, positive terminal J-sign, and an elevated Q-angle. Most patients required only nonsurgical treatments, but 18% underwent surgical interventions for persistent pain.

Patellofemoral pain syndrome (PFPS): a systematic review of anatomy and potential risk factors

Background

Patellofemoral Pain Syndrome (PFPS), a common cause of anterior knee pain, is successfully treated in over 2/3 of patients through rehabilitation protocols designed to reduce pain and return function to the individual. Applying preventive medicine strategies, the majority of cases of PFPS may be avoided if a pre-diagnosis can be made by clinician or certified athletic trainer testing the current researched potential risk factors during a Preparticipation Screening Evaluation (PPSE). We provide a detailed and comprehensive review of the soft tissue, arterial system, and innervation to the patellofemoral joint in order to supply the clinician with the knowledge required to assess the anatomy and make recommendations to patients identified as potentially at risk. The purpose of this article is to review knee anatomy and the literature regarding potential risk factors associated with patellofemoral pain syndrome and prehabilitation strategies. A comprehensive review of knee anatomy will present the relationships of arterial collateralization, innervations, and soft tissue alignment to the possible multifactoral mechanism involved in PFPS, while attempting to advocate future use of different treatments aimed at non-soft tissue causes of PFPS.

Methods

A systematic database search of English language PubMed, SportDiscus, Ovid MEDLINE, Web of Science, LexisNexis, and EBM reviews, plus hand searching the reference lists of these retrieved articles was performed to determine possible risk factors for patellofemoral pain syndrome.

Results

Positive potential risk factors identified included: weakness in functional testing; gastrocnemius, hamstring, quadriceps or iliotibial band tightness; generalized ligamentous laxity; deficient hamstring or quadriceps strength; hip musculature weakness; an excessive quadriceps (Q) angle; patellar compression or tilting; and an abnormal VMO/VL reflex timing. An evidence-based medicine model was utilized to report evaluation criteria to determine the at-risk individuals, then a defined prehabilitation program was proposed that begins with a dynamic warm-up followed by stretches, power and multi-joint exercises, and culminates with isolation exercises. The prehabilitation program is performed at lower intensity level ranges and can be conducted 3 days per week in conjunction with general strength training. Based on an objective one repetition maximum (1RM) test which determines the amount an individual can lift in good form through a full range of motion, prehabilitation exercises are performed at 50–60% intensity.

Conclusion

To reduce the likelihood of developing PFPS, any individual, especially those with positive potential risk factors, can perform the proposed prehabilitation program.

Association between sonographic morphology of vastus medialis obliquus and patellar alignment in patients with patellofemoral pain syndrome

STUDY DESIGN

Descriptive, correlational, anatomical laboratory study.

OBJECTIVES

To investigate the association between the morphology of the vastus medialis obliquus (VMO) and patellar alignment in patients with patellofemoral pain syndrome (PFPS).

BACKGROUND

It has long been presumed that PFPS results from patellar malalignment. Strengthening of the VMO has been suggested as an intervention to treat individuals with PFPS, through correction of abnormal patellar tracking. However, the exact role of the VMO in the etiology and treatment of PFPS is not clear.

METHODS AND MEASURES

This study included 58 patients with PFPS, of which 31 had bilateral involvement. A total of 89 knees were imaged with a Merchant's view radiograph at 45 degrees of knee flexion to measure patellar alignment consisting of patellar tilt and congruence angles. Those 89 knees were also examined with sonography with the knee in full extension and quadriceps relaxed to measure VMO morphology and additional characteristics such as insertion level, insertion ratio, fiber angle, and volume. The level of association between radiographic and sonographic measurements was explored to determine any relationship between patellar alignment and morphology of the VMO.

RESULTS

The patellar tilt angle was negatively correlated with the VMO insertion level (r = -.58, P<.05), insertion ratio (r= -.52, P<.05), and volume (r = -.45, P<.05). In addition, the patellar congruence angle was negatively correlated with the VMO fibers angle (r = -.23, P<.05).

CONCLUSIONS

This study showed that some aspects of VMO morphology, measured in full knee extension with the quadriceps relaxed, were associated with patellar alignment measured with the knee at 45 degrees of flexion. Whether or not VMO morphology serves as a predictor of patella alignment with the knee extended should be the focus of future investigations.

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.