Impaired hemodynamics of the patella in patients with patellofemoral pain: A case-control study.

Purpose: According to the homeostasis model, patellofemoral pain (PFP) arises as a consequence of disturbed homeostasis of anterior structures of the knee due to vascular insufficiency. Near-infrared spectroscopy (NIRS) allows to measure changes of concentrations (µmol/cm2) of (de)-oxygenated hemoglobine (HHb and O2Hb). The aim was to study differences in patellar hemodynamics between patients and healthy controls. Methods: Hemodynamics of patients (n = 30 [female = 20, age = 21.5, BMI = 22.9]) and controls (n = 30 (female = 18, age = 21.4, BMI = 22.4]) were evaluated for two activities ('Prolonged Sitting' and 'Stair Descent'). Blinding for health status was implemented. Results: During 'Prolonged Sitting', PFP patients exhibited smaller decreases in mean changes for HHb (PFP [M = -1.5 to -1.9], healthy controls [M = -2.0 to -2.3]) and O2Hb (PFP [M = -2.0 to -3.2], healthy controls [M = -3.4 to -4.1]). However, these differences were statistically non-significant (p = 0.14-0.82 and p = 0.056-0.18, respectively). Conversely, for 'Stair Descent', PFP patients showed statistically significant smaller decreases in mean changes for HHb (PFP [M = -1.9, SD = 1.8], healthy controls [M = -2.5, SD = 1.7], p = 0.043) and O2Hb (PFP [M = -3.2, SD = 3.2], healthy controls [M = -4.9, SD = 2.7], p = 0.004). Conclusions: The differences suggest potential impairment in patellar hemodynamics in PFP patients, providing support for the homeostasis model. Evidence-based treatment strategies targeting patellar hemodynamics should be further refined and subjected to evaluation in clinical trials. Level of Evidence: Level III.

Large variation in postoperative rehabilitation protocols following operative treatment of osteochondral lesions of the talus: A systematic review and meta-analysis on >200 studies.

PURPOSE: A treatment-specific rehabilitation protocol and well-defined return-to-play criteria guide clinical decision-making on return to normal function, activity, sports and performance after surgical treatment for osteochondral lesion of the talus (OLT). The optimal rehabilitation protocols in the current literature remain unclear. The purpose of this study was to explore the existing literature on rehabilitation protocols from the early postoperative phase to return to sport onwards after different types of surgical treatment of OLTs. METHODS: PubMed, Embase, CDSR, DARE and Central were searched systematically from inception to February 2023 according to the PRISMA 2020 guidelines. All clinical studies with a description of postoperative rehabilitation criteria after surgical treatment of OLTs were included. The primary outcome of this study is the extent of reportage for each rehabilitation parameter expressed in percentage. The secondary outcome is the reported median time for each parameter in rehabilitation protocols for all different treatment modalities (type of surgery). The median time, expressed as number of weeks, for each parameter was compared between different types of surgery. RESULTS: A total of 227 articles were included reporting on 255 different rehabilitation protocols from seven different types of surgery. Weight-bearing instructions were reported in 84%-100% and the use of a cast or walker was prescribed in 27%-100%. Range of motion exercises were described in 54%-100% whereas physical therapy was advised in 21%-67% of the protocols. Any advice on return to sport was described in 0%-67% protocols. A nonparametric analysis of variance showed significant differences between the different surgical treatment modalities for the following parameters between the treatment groups: time to full weight-bearing (p < 0.0003) and return to high impact level of sports (p < 0.0003). Subjective or objective criteria for progression during rehabilitation were reported in only 24% of the studies. CONCLUSION: An in-depth exploration of the current literature showed substantial variation in postoperative rehabilitation guidelines with an associated underreporting of the most important rehabilitation parameters in postoperative protocols after surgical treatment of OLTs. Furthermore, nearly all rehabilitation protocols were constructed according to a time-based approach. Only one out of four reported either objective or subjective criteria. LEVEL OF EVIDENCE: Level IV, systematic review.

Patients with patellofemoral pain have lower soft tissue flexibility of the kinetic chain compared to healthy controls: A case-control study.

INTRODUCTION: Patellofemoral pain (PFP) is a common musculoskeletal condition. Lower limb range of motion (LLROM) evaluates soft tissue flexibility over multiple joints as part of the kinetic chain. The aims were to study: 1) the reliability of a new LLROM test; 2) differences in LLROM between PFP patients and controls; and 3) the relationship between LLROM and pain-free knee function. METHODS: Patients with PFP and matched controls were recruited from a university campus and private physiotherapy clinics, while observers were blinded for health status. Testing LLROM for maximal knee flexion and hip adduction and the sum of these (total ROM) were performed. Measures of reliability (ICC2,1) were established. Univariate linear regression between LLROM and health status and multivariate analysis between LLROM and knee function were performed. RESULTS: Patients (n = 32 (7 male/25 female, age = 22, BMI = 22.7)) and controls (n = 32 (7 male/25 female, age = 20, BMI = 22.3)) were included. The ICC's for intra- and interobserver reliability ranged from 0.83 (95%CI 0.30-0.93) to 0.89 (0.72-0.95). Symptomatic legs had 7°(3-11, p = 0.014) lower knee flexion, 6°(4-8, p ≤ 0.001) lower hip adduction and 13°(8-17, p ≤ 0.001) lower total ROM than non-symptomatic legs. Multivariate analysis revealed an association between total ROM and pain-free knee function (R2 = 0.438, F = 6.544, p ≤ 0.001). CONCLUSIONS: The new LLROM test was found to be reliable. Patients with PFP had lower LLROM, which was associated with impaired pain-free knee function. Whether improving soft tissue flexibility results in enhanced pain-free knee function should be the subject of future research.

Near-Infrared Spectroscopy measurements are reliable for studying patellar bone hemodynamics and affected by venous occlusion, but not by skin compression.

PURPOSE: According to the homeostasis model, patellofemoral pain (PFP) results from disturbed homeostasis due to vascular insufficiency in the anterior knee. Near-Infrared Spectroscopy (NIRS) measures relative changes in concentrations (in µmol/cm2) of (de-)oxygenated hemoglobine (HHb and O2Hb). The aims were to: 1) investigate the characteristics of the NIRS signal derived from the patella during experiments affecting hemodynamics in healthy controls, and 2) determine the test-retest reliability of NIRS in positions clinically relevant for PFP patients. METHODS: Two experiments were conducted on 10 healthy controls and analysed using Student's t-test. Reliability (ICC2,1) was evaluated for two activities ('Prolonged Sitting' and 'Stair Descent') in five PFP patients and 15 healthy controls, performed twice within five days. RESULTS: The NIRS signal (HHb and O2Hb) showed a statistically significant increase (p < .001 - .002) on all optodes (30, 35, 40 mm) during 'Venous Occlusion' (M = 1.0 - 2.0), while it showed no statistically significant change (p = .075 - .61) during 'Skin Compression' (M = -0.9 - 0.9) on the 30 and 35 mm optode. Reliability of NIRS (HHb and O2Hb) ranged from moderate to almost perfect (ICC2,1 = .47 - .95) on the 30 mm optode for 'Prolonged Sitting', and from moderate to substantial (ICC2,1 = .50 - .68) on the 35 mm optode for 'Stair Descent'. CONCLUSIONS: Patella NIRS measurements are affected by venous occlusion, but not by skin compression, and are sufficiently reliable as research application to compare real-time patellar bone hemodynamics. These insights may assist to improve effectiveness of evidence-based treatment strategies for PFP. TRIAL REGISTRATION: ISRCTN Trial Registration under number: 90377123.

Short-term effectiveness of an intervention targeting lower limb range of motion on pain and disability in patellofemoral pain patients: A randomized, non-concurrent multiple-baseline study.

INTRODUCTION: Patellofemoral pain (PFP) is a common and often long-standing musculoskeletal condition. Evidence of the effectiveness of interventions addressing soft tissue flexibility is conflicting and of inconsistent scientific quality. However, reduced soft tissue flexibility can negatively affect patellofemoral joint kinematics. Lower limb range of motion (LLROM) reflects soft tissue flexibility throughout the kinetic chain. The aim was to evaluate the short-term effectiveness of an intervention targeting LLROM on pain and disability in patients with PFP. METHODS: A randomized, non-concurrent, multiple-baseline single-case design with a two-week intervention phase and baseline and postintervention phase with varying length was conducted. Eight participants (5 females, 3 males) of age 19(±1.6) years, weekly sports participation 12(±3.1) hours and 17(±14) months symptom duration were included. The Anterior Knee Pain Scale - Dutch Version (AKPS-DV) and the Patient Specific Complaint Scale (PSCS) were administered twice a week. After allocating participants to one of four subgroups of reduced LLROM the intervention was applied. The intervention consisted of soft tissue techniques (mobilization, taping, and stretching). RESULTS: Participant 3 and 6 showed a medium and small but statistically significant positive effect on the AKPS-DV. Participant 2 showed a large and statistically significant positive effect on the PSCS. CONCLUSIONS: This study provides moderate evidence that an intervention targeting LLROM in patients with PFP reduces pain and disability in the short-term. Further research is needed to evaluate the long-term effectiveness and optimize individual treatment outcomes.

Normal values for hip muscle strength and range of motion in elite, sub-elite and amateur male field hockey players.

OBJECTIVES: To determine normal values for hip strength and range of motion (ROM) of elite, sub-elite and amateur male field hockey players and to examine the effect of age, leg dominance, playing position, playing level and non-time-loss groin pain on hip strength and ROM. DESIGN: Cross-sectional study. SETTING: Physical testing took place at field hockey clubs. PARTICIPANTS: Male field hockey players competing in the three highest Dutch field hockey leagues (n = 104). MAIN OUTCOME MEASURES: Eccentric adduction, eccentric abduction, adductor squeeze strength, adduction/abduction ratio, internal rotation, external rotation and bent knee fall out (BKFO). RESULTS: Strength and ROM values (mean ± standard deviation) were: adduction = 2.8 ± 0.4 Nm/kg, abduction = 2.6 ± 0.4 Nm/kg, adduction/abduction ratio = 1.1 ± 0.2, squeeze test = 4.5 ± 0.8 N/kg, internal rotation = 34° ± 11°, external rotation = 47° ± 9°, BKFO = 15 ± 4 cm. Age, leg dominance, playing position, playing level and non-time-loss groin pain had no effect on these profiles. CONCLUSIONS: Normal values were established for hip strength and ROM of male field hockey players and showed to be independent of age, leg dominance, playing position, playing level and non-time-loss groin pain.

Including performance level lowers prevalence of non-timeloss groin injury. A cross-sectional study in 383 female amateur football players.

OBJECTIVE: To study the preseason prevalence of groin injury with normal and reduced performance. DESIGN: Cross-sectional cohort. SETTINGS: Online survey. PARTICIPANTS: 383 Dutch female amateur football players (35 teams). MAIN OUTCOME MEASURES: Prevalence of groin injury per injury group (timeloss or non-timeloss) using a general questionnaire and per performance group (groin pain with normal or reduced performance) using subscales Pain and Participation in Physical Activities of the Hip And Groin Outcome Score (HAGOS). Levels and between-group differences of groin-related symptoms and problems (HAGOS) for injury and performance groups. The injury groups from which players with groin pain and normal performance originate. RESULTS: Prevalence of non-timeloss groin injury was 22% (95% confidence interval (95%CI) = 18-26) (n = 84), 7% (95%CI = 5-10) (n = 26) for timeloss groin injury, 21% (95%CI = 17-25) (n = 80) for pain + normal performance and 16% (95%CI = 12-20) (n = 61) for pain + reduced performance. HAGOS-scores differed between injury (P < .022) and performance groups (p < .043). Twenty-three players (27%) with pain + normal performance originated from the non-timeloss groin injury group (100%). CONCLUSION: As female amateur football players with groin pain and normal performance are considered non-injured, the prevalence of non-timeloss groin injury lowers by a quarter. These players have lower HAGOS scores than non-injured players without pain yet higher scores than those with non-timeloss groin injury.

The decline step-down test measuring the maximum pain-free flexion angle: A reliable and valid performance test in patients with patellofemoral pain.

OBJECTIVES: Patients with patellofemoral pain (PFP) experience pain while descending stairs. To date no reliable and valid performance-test exists to assess the maximum pain-free knee flexion angle (MPFFA) as outcome measure during a step-down task. Therefore, the intra- and inter-observer reliability and construct validity of the decline step-down test (DSDT) measuring the MPFFA in patients with PFP were evaluated. DESIGN: Reliability and construct validity. SETTING: Private practices in Nijmegen and Utrecht, the Netherlands. PARTICIPANTS: Patients with PFP. MAIN OUTCOME MEASURES: The reliability was assessed by repeated measurements of the MPFFA during the DSDT. The construct validity was assessed by correlating the measurements on the DSDT with the Anterior Knee Pain Scale Dutch Version (AKPS-DV) based on a pre-set hypothesis. RESULTS: Thirty-two participants (forty-eight knees) were eligible for inclusion. The intraclass correlation coefficient (ICC) for intra-observer reliability was ICC2,1 = 0.83 and ICC2,1 = 0.85 for inter-observer reliability. The 95% limits of agreement (LoA) showed a width of 27.56° for intra-observer reliability and a width of 24.42° for inter-observer reliability. There was an average positive correlation between the DSDT and the total score on the AKPS-DV (rs = 0.31, p = 0.030). CONCLUSION: The DSDT measuring the MPFFA is reliable and valid in patients with PFP.

Ultrasound characteristics of the lateral retinaculum in 10 patients with patellofemoral pain syndrome compared to healthy controls.

BACKGROUND: Histopathologic changes of the lateral retinaculum are described in patients with patellofemoral pain syndrome (PFPS). No information is available on the presence of structural changes of the lateral retinaculum on ultrasound examination in patients with PFPS. PURPOSE: To describe ultrasound characteristics and colour Doppler findings in patients with unilateral PFPS and in healthy controls. METHODS: 10 patients with unilateral PFPS and 10 healthy control subjects underwent ultrasound and colour Doppler examination of the lateral retinaculum of both knees. Thickness of the lateral retinaculum was measured at three predefined locations. In addition presence of neovascularisation was assessed. RESULTS: Thickness of the lateral retinaculum of both affected (mean [SD] of three locations 4.0 [1.4] mm, 95%CI: 1.2-6.8) and asymptomatic (3.7 [0.8] mm, 95%CI: 2.1-5.3) knees was increased in the patient group compared to the control subjects (3.0 [0.1] mm, 95%CI: 2.8-3.2), although not reaching statistical significance. Positive colour Doppler signals of the lateral retinaculum were found in 4 patients and in none of the control subjects (4/10 versus 0/10; 2 × 2 Fisher's exact test 1-tailed p = 0.0433; 2-tailed p = 0.0866; mid p value = 0.0217). CONCLUSIONS: The results of these measurements indicate a trend towards a larger thickness of the lateral retinaculum and showed neovascularisation measured by ultrasound and colour Doppler examination in patients with PFPS. The larger thickness of the lateral retinaculum on ultrasound examination was found in both affected and in asymptomatic knees of the patients, supporting the concept that PFPS is a bilateral rather than a unilateral disorder. Further research is needed to unravel the role of the lateral retinaculum in pathogenesis of PFPS and to clarify the role of the lateral retinaculum as a target for therapy in patients with PFPS.