Exploring overweight and obesity beyond body mass index:A body composition analysis in people with and without patellofemoral pain

Background:We compared body mass index(BMI),body fat,and skeletal muscle mass between(1) a mixed-sex nonathletic cohort of people with patellofemoral pain(PFP) and pain-free people,and(2) a nonathletic cohort of people with PFP and pain-free people subgrouped by sex(i.e.,men and women with PFP vs.pain-free men and women).Methods:This cross-sectional study included 114 people with PFP(71 women,43 men) and 54 pain-free controls(32 women,22 men).All participants attended a single testing session to assess body composition measures,which included BMI,percentage of body fat(%BFBioimpedance),and skeletal muscle mass(both assessed by bioelectrical impedance analysis),and percentage of body fat(%BFskinfoid)(assessed by skinfold caliper analysis).A one-way univariate analysis of covariance(age and physical activity levels as covariates) was used to compare body composition measures between groups(i.e.,PFP vs.pain-free group;women with PFP vs.pain-free women;men with PFP vs.pain-free men).Results:Women with PFP presented significantly higher BMI,%BFBiompedance,and %BFSkinfold,and lower skeletal muscle mass compared to pain-free women(p≤0.04;effect size:-0.47 to 0.85).Men with PFP and men and women combined had no differences in BMI,%BFBioimpedance,%BFSkinfold,and skeletal muscle mass compared to their respective pain-free groups(p> 0.05).Conclusion:Our findings indicate that BMI and body composition measures should be considered as part of the evaluation and management of people with PFP,especially in women,who have demonstrated higher BMI and body fat and lower skeletal muscle mass compared to pain-free controls.Future studies should not assess body composition measures in a mixed-sex population without distinguishing men participants from women participants.

Overweight and obesity in young adults with patellofemoral pain:Impact on functional capacity and strength

Purpose:This study aimed to(a)investigate the proportion of overweight/obesity in a cohort of young adults with patellofemoral pain(PFP)and(b)explore the association of body mass index(BMI),body fat,and lean mass with functional capacity and hip and knee strength in people with PFP.Methods:We included a mixed-sex sample of young adults(18-35 years old)with PFP(n=100).Measurements for BMI,percentage of body fat,and lean mass(assessed by bioelectrical impedance)were obtained.Functional capacity was assessed by the Anterior Knee Pain Scale,plank test,and single-leg hop test.Strength of the knee extensors,knee flexors,and hip abductors was evaluated isometrically using an isokinetic dynamometer.The proportion of overweight/obesity was calculated based on BMI.The association between BMI,body fat,and lean mass and functional capacity and strength was investigated using partial correlations,followed by hierarchical regression analysis,adjusted for covariates(sex,bilateral pain,and current pain level).Results:A total of 38%of our cohort had their BMI categorized as overweight/obese.Higher BMI was associated with poor functional capacity(ΔR^(2)=0.06-0.12,p<0.001)and with knee flexion strength only(ΔR^(2)=0.04,p=0.030).Higher body fat was associated with poor functional capacity(ΔR^(2)=0.05-0.15,p≤0.015)and reduced strength(ΔR^(2)=0.15-0.23,p<0.001).Lower lean mass was associated with poor functional capacity(ΔR^(2)=0.04-0.13,p≤0.032)and reduced strength(ΔR^(2)=0.29-0.31,p<0.001).Conclusion:BMI,body fat,and lean mass should be considered in the assessment and management of young people with PFP because it may be detrimental to function and strength.

Combined medial patellofemoral ligament and medial patellotibial ligament reconstruction in recurrent patellar instability:A systematic review and meta-analysis

BACKGROUND The medial patellofemoral ligament(MPFL),along with the medial patellotibial ligament(MPTL)and medial patellomeniscal ligament,aid in the stabilization of the patellofemoral joint.Although the MPFL is the primary stabilizer and the MPTL is a secondary limiter,this ligament is critical in maintaining joint stability.There have been few studies on the combined MPFL and MPTL reconstruction and its benefits.AIM To look into the outcomes of combined MPFL and MPTL reconstruction in frequent patellar instability.METHODS By May 8,2022,four electronic databases were searched:Medline(PubMed),Scopus,Web of Science,and Google Scholar.General keywords such as"patellar instability,""patellar dislocation,""MPFL,""medial patellofemoral ligament,""MPTL,"and"medial patellotibial ligament"were co-searched to increase the sensitivity of the search.RESULTS The pooled effects of combined MPFL and MPTL reconstruction for Kujala score(12-mo followup)and Kujala score(24-mo follow-up)were positive and incremental,according to the findings of this meta-analysis.The mean difference between the Cincinnati scores was also positive,but not statistically significant.The combination of the two surgeries reduces pain.According to cumulative meta-analysis,the trend of pain reduction in various studies is declining over time.CONCLUSION The combined MPFL and MPTL reconstruction has good clinical results in knee function and,in addition to providing good control to maintain patellofemoral joint balance,the patient's pain level decreases over time,making it a valid surgical method for patella stabilization.

Interference screws vs.suture anchors for isolated medial patellofemoral ligament femoral fixation:A systematic review

Purpose:The present study aimed to systematically review and compare 2 femoral autograft fixation techniques,namely,interference screws and suture anchors,for isolated medial patellofemoral ligament reconstruction in patients with recurrent patellofemoral instability at mid-to long-term follow-up.Methods:A literature search was performed in September 2020.All studies reporting the outcomes of primary isolated medial patellofemoral ligament reconstruction for recurrent patellofemoral instability were considered for inclusion.Only studies reporting the type of femoral autograft fixation under examination were considered.Studies reporting data from patients with elevated tibial tuberosity-tibial groove,patella alta,and/or Dejour’s trochlear dysplasia types C and D,were not included.Only articles reporting data with a minimum follow-up period of 18 months were considered.Results:Data from 19 studies(615 patients)were retrieved.The overall age was 24.4±6.7 years(mean±SD).The mean follow-up was 46.5±20.9 months.There were 76 patients in the anchor group and 539 in the screw group.Comparability was found with regard to age and follow-up duration between the 2 study groups.There was comparability between the Kujala,Lysholm,and Tegner scores at baseline.At the last follow-up,no worthy differences were found in terms of mean Kujala(+2.1%;p=0.04),Lysholm(+1.7%;p=0.05),and Tegner(+15.8%;p=0.05)scores.Although complications occurred almost exclusively in the screw cohort,no statistically significant difference was found.Conclusion:Femoral autograft fixation through interference screws or suture anchors report similar clinical scores and rate of apprehension test,persistent joint instability,re-dislocations,and revisions.These results must be interpreted within the limitations of the present study.

Deepening trochleoplasty combined with balanced medial patellofemoral ligament reconstruction for an adequate graft tensioning

AIM To evaluate our modified deepening trochleoplasty com-bined with a balanced medial patellofemoral ligament(MPFL) reconstruction for soft tissue alignement. METHODS Thirty-three knees with with recurrent patellar dislocations and a trochlear dysplasia in 30 patients(m/f = 12/21, mean age 24 ± 9 years) underwent a combination of a modified deepening trochleoplasty and a balanced MPFL reconstruction for a medial soft tissue alignement. After a mean follow-up period of 29 ± 23 mo, patients' return to sports, possible complications as well as the clinical outcomes using the Kujala, International Knee Documentation Committee(IKDC) and Lysholm scoring were evaluated. Moreover, patients' satisfaction with the general outcome, the cosmetic outcome, the pre-and postoperative pain and a potential avoidance behaviour were assessed with additional standardized questionnaires which also included different visual analog scales. RESULTS There were no signs of a persistent instability. The Kujala score improved from a mean of 64 ± 16 points to 94 ± 9 points, the Lysholm score improved from a mean of 63 ± 17 to 95 ± 6 points and the IKDC score from 58 ± 11 to 85 ± 12 points, P < 0.0001, respectively. The assessment of pain using a visual analog scale showed a significant pain reduction from a mean of 4.8 ± 2.0 to 1.3 ± 3.4 points(P < 0.0001). Two of 26 cases(92%) who were engaged in regular physical activity before surgery did not return to full sporting activities. One patient felt that his sport was too risky for his knee and reported an ongoing avoidance behaviour. The other patient preferred to wait for surgery of her contralateral knee. Of the eight patients who were not engaged in sporting activities before surgery, three started regular sporting activities after surgery. In 31 of the 33 cases(94%), the patients were very satisfied with the clinical outcome of the surgery. Regarding the cosmetic results, no patients felt impaired in their self-confidence and in their clothing decisions. CONCLUSION Our technique shows a good clinical outcome in terms of the common scorings as well as in terms of pain, return to sports and patient satisfaction.

Research progress of medial patellofemoral ligament reconstruction

Patellar dislocation is a common disease in orthopaedics. The incidence of patellar dislocation is the highest in adolescents with an average age of 21.4 years. There are many methods to treat the dislocation of patella, among which the reconstruction of medial patellofemoral ligament (MPFL) is the main one. In this paper, the biomechanics and graft selection of medial patellofemoral ligament reconstruction were discussed in detail by reviewing the relevant literature at home and abroad. The femoral insertion, patellofemoral fixation and postoperative complications were also discussed, in order to provide reference for clinical workers. In view of different postoperative complications, there are many kinds of optimization schemes, and reasonable choice of operation scheme is the premise of good operation satisfaction rate.

Failed medial patellofemoral ligament reconstruction:Causes and surgical strategies

Patel ar instability is a common clinical problem encountered by orthopedic surgeons specializing in the knee. For patients with chronic lateral patellar instability, the standard surgical approach is to stabilize the patella through a medial patellofemoral ligament(MPFL) reconstruction. Foreseeably, an increasing number of revision surgeries of the reconstructed MPFL will be seen in upcoming years. In this paper, the causes of failed MPFL reconstruction are analyzed:(1) incorrect surgical indication or inappropriate surgical technique/patient selection;(2) a technical error; and(3) an incorrect assessment of the concomitant risk factors for instability. An understanding of the anatomy and biomechanics of the MPFL and cautiousness with the imaging techniques while favoring clinical over radiological findings and the use of common sense to determine the adequate surgical technique for each particular case, are critical to minimizing MPFL surgery failure. Additionally, our approach to dealing with failure after primary MPFL reconstruction is also presented.

Lateral patellofemoral ligament reconstruction to restore functional capacity in patients previously undergoing lateral retinacular release

AIM: To study patient outcomes after surgical correction for iatrogenic patellar instability.METHODS: This retrospective study looked at 17 patients(19 knees) suffering from disabling medial patellar instability following lateral release surgery. All patients underwent lateral patellofemoral ligament(LPFL) reconstruction by a single surgeon. Assessments in all 19 cases included functional outcome scores, range of motion, and assessment for the presence of apprehension sign of the patella to determine if LPFL reconstruction surgery was successful at restoring patellofemoral stability.RESULTS: No patients reported any residual postoperative symptoms of patellar instability. Also no patients demonstrated medial patellar apprehension or examiner induced subluxation with the medial instability test described earlier following LPFL reconstruction. Furthermore, all patients recovered normal range of motion compared to the contralateral limb. For patients with pre and postoperative outcome scores, the mean overall knee injury and osteoarthritis outcome score increased significantly, from 34.39 preoperatively(range: 7.7-70.12) to 69.54 postoperatively(range:26.82-91.46) at final follow-up(P < 0.0001). CONCLUSION: This novel technique for LPFL reconstruction is effective at restoring lateral restraint of the patellofemoral joint and improving joint functionality.

Patellofemoral MRI Alterations Following Single Bundle ACL Reconstruction with Hamstring Autografts Are Associated with Quadriceps Femoris Atrophy

High incidence of patellofemoral pain and patellofemoral joint osteoarthritis was found following anterior cruciate ligament(ACL)reconstruction.The unstability of patellofemoral joint might be an important contribution factor.This study was designed to define the relationship between the unstability of patellofemoral joint and quadriceps femoris atrophy.Twenty patients underwent MRI scan before ACL reconstruction and every two weeks after surgery,until 12 weeks.The merchant’s patellar congruence angle,lateral inclination angle,and quadriceps femoris muscle cross-sectional area were measured and the relationship between the changes of angles and the ratio of quadriceps femoris atrophy was studied by multiple regression analysis.Significant quadriceps femoris atrophy was observed after ACL reconstruction during the follow-up period of 12 weeks.The merchant’s patellar congruence angle and lateral inclination angle significantly changed after surgery.The alterations of the merchant’s patellar congruence angle were significantly correlated with the atrophy ratio of vastus medialis(coefficient=-5.76)and vastus lateralis(coefficient=8.35)during the follow-up period of 12 weeks.The alterations of lateral inclination angle were significantly correlated with the atrophy ratio of vastus medialis(coefficient=20.62),vastus lateralis(coefficient=-11.38)and rectus femoris(coefficient=-0.469)during the follow-up period 12 weeks.To sum up,ACL reconstruction can alleviate the dysfunction of patellofemoral joint to a certain extent.But,the unbalanced atrophy of quadriceps femoris once again destroyed the stability of patellofemoral joint following the operation,which might be one cause of patellofemoral joint pain and early onset of osteoarthritis after ACL reconstruction.So,rehabilitation training that focuses on quadriceps femoris especially the vastus medialis shortly following operation is suggested.

A Novel Knee Orthosis in the Treatment of Patellofemoral Pain Syndrome

Context: Patellofemoral Pain (PFPS) accounts for up to 25% of knee injuries in sports medicine clinics, with up to 91% of symptoms unresolved after conservative treatment at 5 years. The variability of response to treatment reflects its multi-factorial biomechanical etiologies. Bracing has been utilized to modify patellofemoral kinematics, generally by increasing patellofemoral contact area. The DJO Reaction orthosis is unique in its shock-absorbing elastomeric design, which is created to dissipate peak stress and enhance patellar tracking. Objective: To assess whether the DJO Reaction Brace reduces pain and improves functional outcomes in patients with chronic PFPS. Design: Cohort Series. Setting: Academic Sports Medicine Clinic. Patients: Twenty-two individuals between 18 and 40 years old with chronic patellofemoral pain have failed conservative treatment. Intervention: DJO Reaction Brace. Main Outcome Measures: Kujala Anterior Knee Pain Scale, Knee Injury and Osteoarthritis Outcome Score. Results: Seven males and 10 females with an age range of 19 - 39 years old complete the study. At an average follow-up time of 55 days, the Kujala score significantly improves by 9.8%, and KOOS Scores increase by the following statistically significant amounts: symptom 3.2%, pain 10.7%, sports and recreation 12.9%, quality of life 20.2%. Conclusion: The DJO Reaction orthosis reduces knee pain, increases function, and enhances quality of life with individuals with PFPS and is effective in the conservative care of patellofemoral pain syndrome.

Radiological evaluation of patellofemoral instability and possible causes of assessment errors

Patellofemoral instability(PI)is the disruption of the patella’s relationship with the trochlear groove as a result of abnormal movement of the patella.To identify the presence of PI,conventional radiographs(anteroposterior,lateral,and axial or skyline views),magnetic resonance imaging,and computed tomography are used.In this study,we examined four main instability factors:Trochlear dysplasia,patella alta,tibial tuberosity–trochlear groove distance,and patellar tilt.We also briefly review some of the other assessment methods used in the quantitative and qualitative assessment of the patellofemoral joint,such as patellar size and shape,lateral trochlear inclination,trochlear depth,trochlear angle,and sulcus angle,in cases of PI.In addition,we reviewed the evaluation of coronal alignment,femoral anteversion,and tibial torsion.Possible causes of error that can be made when evaluating these factors are examined.PI is a multi-factorial problem.Many problems affecting bone structure and muscles morphologically and functionally can cause this condition.It is necessary to understand normal anatomy and biomechanics to make more accurate radiological measurements and to identify causes.Knowing the possible causes of measurement errors that may occur during radiological measurements and avoiding these pitfalls can provide a more reliable road map for treatment.This determines whether the disease will be treated medically and with rehabilitation or surgery without causing further complications.

Short-term effectiveness of high-and low-intensity percutaneous electrolysis in patients with patellofemoral pain syndrome:A pilot study

BACKGROUND Unilateral patellofemoral pain syndrome(PFPS)is the most frequently diagnosed knee condition in populations aged<50 years old.Although the treatment of myofascial trigger points(MTrPs)is a common and effective tool for reducing pain,previous studies showed no additional benefits compared with placebo in populations with PFPS.Percutaneous electrolysis is a minimally invasive approach frequently used in musculotendinous pathologies which consists of the application of a galvanic current through dry needling(DN).AIM To evaluate changes in sensitivity,knee pain perception and perceived pain during the application of these three invasive techniques.METHODS A triple-blinded,pilot randomized controlled trial was conducted on fifteen patients with unilateral PFPS who were randomized to the high-intensity percutaneous electrolysis(HIPE)experimental group,low-intensity percutaneous electrolysis(LIPE)experimental group or DN active control group.All interventions were conducted in the most active MTrP,in the rectus femoris muscle.The HIPE group received a 660 mA galvanic current for 10 s,the LIPE group 220 mA×30 s and the DN group received no galvanic current.The MTrP and patellar tendon pain pressure thresholds(PPTs)and subjective anterior knee pain perception(SAKPP)were assessed before,after and 7 d after the single intervention.In addition,perceived pain during the intervention was also assessed.RESULTS Both groups were comparable at baseline as no significant differences were found for age,height,weight,body mass index,PPTs or SAKPP.No adverse events were reported during or after the interventions.A significant decrease in SAKPP(both HIPE and LIPE,P<0.01)and increased patellar tendon PPT(all,P<0.001)were found,with no differences between the groups(VAS:F=0.30;η2=0.05;P>0.05;tendon PPT immediate effects:F=0.15;η2=0.02;P>0.05 and tendon PPT 7-d effects:F=0.67;η2=0.10;P>0.05).A significant PPT increase in rectus femoris MTrP was found at follow-up in both the HIPE and LIPE groups(both,P<0.001)with no differences between the groups(immediate effects:F=1.55;η2=0.20;P>0.05 and 7-d effects:F=0.71;η2=0.10;P>0.05).Both HIPE and LIPE interventions were considered less painful compared with DN(F=8.52;η2=0.587;P<0.01).CONCLUSION HIPE and LIPE induce PPT changes in MTrPs and patellar tendon and improvements in SAKPP,and seem to produce less pain during the intervention compared with DN.

Femoro Patella Vialla patellofemoral arthroplasty: An independent assessment of outcomes at minimum 2-year follow-up

AIM: To determine outcomes using the Femoro-Patella Vialla(FPV) arthroplasty and if there is an ideal patient for this implant. METHODS: A total of 41 FPV patellofemoral joint replacements were performed in 31 patients(22 females, 9 males, mean age 65 years). Mean followup was 3.2 years(minimum 2 years). Radiographs were reviewed preoperatively and postoperatively. We assessed whether gender, age, previous surgery, patella atla or trochlear dysplasia influenced patient satisfaction or patient functional outcome.RESULTS: The median Oxford Knee Score was 40 and the median Melbourne Patellofemoral Score was 21 postoperatively. Seventy-six percent of patients were satisfied, 10% unsure and 14% dissatisfied postoperatively. There was no radiological progression of tibiofemoral joint arthritis, using the Ahlback grading,in any patient. One patient, who was diagnosed with rheumatoid arthritis postoperatively, underwent revision to total knee replacement. There were no intraoperative lateral releases and no implant failures. Gender, age, the presence of trochlear dysplasia, patella alta or bilateral surgery did not influence patient outcome. Previous surgery did not correlate with outcome. CONCLUSION: In contrast to the current literature, the FPV shows promising early results. However, we cannot identify a subgroup of patients with superior outcomes.

Timing and Classication of Patellofemoral Osteoarthritis Patients Using Fast Large Margin Classifier

:Surface electromyogram(sEMG)processing and classication can assist neurophysiological standardization and evaluation and provide habitational detection.The timing of muscle activation is critical in determining various medical conditions when looking at sEMG signals.Understanding muscle activation timing allows identication of muscle locations and feature validation for precise modeling.This work aims to develop a predictive model to investigate and interpret Patellofemoral(PF)osteoarthritis based on features extracted from the sEMG signal using pattern classication.To this end,sEMG signals were acquired from ve core muscles over about 200 reads from healthy adult patients while they were going upstairs.Onset,offset,and time duration for the Transversus Abdominus(TrA),Vastus Medialis Obliquus(VMO),Gluteus Medius(GM),Vastus Lateralis(VL),and Multidus Muscles(ML)were acquired to construct a classication model.The proposed classication model investigates function mapping from real-time space to a PF osteoarthritis discriminative feature space.The activation feature space of muscle timing is used to train several large margin classiers to modulate muscle activations and account for such activation measurements.The fast large margin classier achieved higher performance and faster convergence than support vector machines(SVMs)and other state-of-the-art classiers.The proposed sEMG classication framework achieved an average accuracy of 98.8%after 7 s training time,improving other classication techniques in previous literature.

The Effect of Isometric and Isotonic Exercises of Lower Limbs Extensor Sling on Static and Dynamic Balance in Basketball Players with Patellofemoral Pain

Background: Patellofemoral Pain Syndrome (PFPS) is one of the most common conditions among athletes. Although there are various causes for this condition, reduced balance is the problem most frequently expressed by these patients. The aim of the present study was to examine the effect of Extensor Muscle Sling Isometric and Isotonic (EMSII) exercises of lower limbs on female basketball players suffering from PFPS. Method: A total of 30 participants, all female basketball players suffering from PFPS, with an average age of 20 - 30 years, were divided into two isometric/isotonic and control experimental groups. Eight weeks of isometric and isotonic exercises were recommended to the participants with a focus on EMSII exercises of lower limbs in two four-week phases. The control group received no specific exercise program. Pre-test and post-test included the use of Stork balance test (SBT) and Y Balance tests (YBT) to assess the static and dynamic balance, respectively. Results: After eight weeks of performing separate isometric and isotonic exercises on the mentioned muscles, and according to the results of the pre-test, a significant increase was observed in the results of both static and dynamic balance tests (P Conclusion: EMSII exercises of lower limbs showed a significant effect on the increased balance. Recommended exercises can be suggested according to the type of exercises as a factor for increasing static and dynamic balance.

Effect of Knee Valgus Angle during Single Leg Squat and Horizontal Hop for Distance in Patients with Patellofemoral Pain and Controls

Background: Patellofemoral pain (PFP) is considered one of the most common dysfunctions of the lower extremities. Faulty lower limb mechanics and increased of knee valgus on loaded tasks are believed to play an important role in the development of PFP. Objective: To figure out if male PFP patients during single leg horizontal hop for distance and squat with greater knee valgus than controls, and if the nature of the task changes the angles of knee valgus. Methods: Twenty males with unilateral PFP formed the patient group and forty-five asymptomatic males formed the control group. Two dimensional (2-D) frontal plane projection angle (FPPA) was used during single leg squatting and horizontal hop for distance tasks. Results: For the single leg squat, the mean of 6.96°, 9.80°, 15.04° was reported in the control, PFP asymptomatic knee, and PFP symptomatic knee, respectively. For the single leg horizontal hop for distance, the mean of 11.63°, 13.72°, 19.17° was reported in the control, PFP asymptomatic knee, and PFP symptomatic knee, respectively. These differences were significant (p < 0.002) for both tasks. Conclusions: Patients with PFP represented with greater knee valgus angle than what was found in either their asymptomatic limb or in the control group.

Patellofemoral Outcome after Medial Unicompartmental Knee Replacement: A Retrospective Study of 25 Cases

Introduction: Osteoarthritis and impingement, in patellofemoral compartment after partial arthroplasty, have been rarely reported. The purpose of our study was to evaluate outcome at long-term follow-up. Methods: We have reviewed retrospectively twenty-five unicompartmental arthroplasties. The medial parapatellar approach was used in all cases. Patients have been evaluated with regard to patellar impingement and osteoarthritic changes revealed by radiographs. The mean follow-up was 10.4 years. The clinical scoring system of the Knee Society and specific questions regarding patellofemoral symptoms were used for functional outcome. Patellofemoral complications such as osteoarthritis, impingement and the position of the femoral component were diagnosed on X-ray views of the knee. Results: At the final follow-up, fifteen knees revealed lateral patellofemoral osteoarthritis and four knees had patellofemoral impingement. Excepted of two cases, all knees with patella impingement did not revealed degenerative modifications. Anterior pain of the knee was noted more frequently in knees with patellar complications. Patellar impingement was considered the first cause of knee pain, more than knees with degenerative modifications. Only one revision surgery was indicated in front of patellofemoral conflict. The occurrence of patellar impingement depends on the surgical procedure. The anterior position of the femoral component seems to increase the frequency of such complication. Conclusion: Several degenerative modifications may occur in the patello-femoral compartment following partial knee arthroplasty. Patellar impingement and total knee arthritis are the most reported modifications. Functional outcome may be affected progressively when these changes become obvious. Patellar impingement is the major cause of knee pain and needs revision.

Radiological evaluation of patellofemoral instability and possible causes of assessment errors:Letter to the editor

This letter to the editor is a commentary on the study titled"Radiological evaluation of patellofemoral instability and possible causes of assessment errors".There are some pertinent structural changes and radiological findings that should be considered in the setting of traumatic knee injuries,as their recognition is of paramount importance.

Influence of patellofemoral joint degeneration on clinical outcomes after medial unicompartmental knee arthroplasty

Background:Patellofemoral joint(PFJ)degeneration has traditionally been regarded as a contraindication to unicompartmental knee arthroplasty(UKA).More recently,some researchers have proposed that PFJ degeneration can be ignored in medial UKA,and others have proposed that this change should be reviewed in PFJ degenerative facets and severity.This study aimed to systematically evaluate the effect of PFJ degeneration on patient-reported outcome measures(PROMs)and revision rates after medial UKA.Methods:Electronic databases(PubMed,Embase,Web of Science,etc.)were searched for studies assessing the influence of PFJ degeneration on medial UKA.A random-effects meta-analysis was conducted for the Oxford knee score(OKS),Knee society score(KSS),and revision rates and stratified by PFJ degenerative facets(medial/lateral/trochlear/unspecified),severe PFJ degeneration(bone exposed),and bearing type(mobile/fixed).Heterogeneity was assessed by the Cochran Q test statistic and chi-squared tests with the I-squared statistic.Results:A total of 34 articles with 7007 knees(2267 with PFJ degeneration)were included(5762 mobile-bearing and 1145 fixed-bearing and 100 unspecified).Slight to moderate degenerative changes in the medial and trochlear facets did not decrease the OKS and KSS,and only lateral facets significantly decreased the OKS(mean difference[MD]=-2.18,P<0.01)and KSS(MD=-2.61,P<0.01).The severity degree of PFJ degeneration had no additional adverse effect on the OKS,KSS,or revision rates.For mobile-bearing UKA,only lateral PFJ degeneration significantly decreased the OKS(MD=-2.21,P<0.01)and KSS(MD=-2.44,P<0.01).For fixed-bearing UKA,no correlation was found between PROMs/revision rates and PFJ degeneration.Conclusion:For medial mobile-bearing UKA,slight to moderate degenerative changes in the PFJ,except lateral facet,did not compromise PROMs or revision rates.For medial fixed-bearing UKA,although it might not be conclusive enough,PROMs or revision rates were not adversely affected by PFJ degeneration(regardless of the facet).

There is more to the knee joint than just the quadriceps:A systematic review with meta-analysis and evidence gap map of hamstring strength,flexibility,and morphology in individuals with gradual-onset knee disorders

Background:Impairments in hamstring strength,flexibility,and morphology have been associated with altered knee biomechanics,pain,and function.Determining the presence of these impairments in individuals with gradual-onset knee disorders is important and may indicate targets for assessment and rehabilitation.This systematic review aimed to synthesize the literature to determine the presence of impairments in hamstring strength,flexibility,and morphology in individuals with gradual-onset knee disorders.Methods:Five databases(MEDLINE,Embase,CINAHL,SPORTDiscus,and Web of Science)were searched from inception to September 2022.Only studies comparing hamstring outcomes(e.g.,strength,flexibility,and/or morphology)between individuals with gradual-onset knee disorders and their unaffected limbs or pain-free controls were included.Meta-analyses for each knee disorder were performed.Outcome-level certainty was assessed using the Grading of Recommendations Assessment,Development,and Evaluation,and evidence gap maps were created.Results:Seventy-nine studies across 4 different gradual-onset knee disorders(i.e.,knee osteoarthritis(OA),patellofemoral pain(PFP),chondromalacia patellae,and patellar tendinopathy)were included.Individuals with knee OA presented with reduced hamstring strength compared to pain-free controls during isometric(standard mean difference(SMD)=-0.76,95%confidence interval(95%CI):-1.32 to-0.21)and concentric contractions(SMD=-0.97,95%CI:-1.49 to-0.45).Individuals with PFP presented with reduced hamstring strength compared to painfree controls during isometric(SMD=-0.48,95%CI:-0.82 to-0.14),concentric(SMD=-1.07,95%CI:-2.08 to-0.06),and eccentric contractions(SMD=-0.59,95%CI:-0.97 to-0.21).No differences were observed in individuals with patellar tendinopathy.Individuals with PFP presented with reduced hamstring flexibility when compared to pain-free controls(SMD=-0.76,95%CI:-1.15 to-0.36).Evidence gap maps identified insufficient evidence for chondromalacia patellae and hamstring morphology across all gradual-onset knee disorders.Conclusion:Our findings suggest that assessing and targeting impairments in hamstring strength and flexibility during rehabilitation may be recommended for individuals with knee OA or PFP.