Effect of isometric quadriceps exercise on local microcirculation of the infrapatellar fat pad in female patients with knee osteoarthritis.

OBJECTIVE: To elucidate the local microcirculation of the infrapatellar fat pad (IFP) in patients with knee osteoarthritis (KOA) by determining the changes in IFP hardness and hemoglobin concentration during isometric quadriceps exercise (IQE). DESIGN: In this observational cross-sectional study, patients diagnosed with bilateral KOA were included in the KOA group (30 knees), healthy older adults in the control group (20 knees), and younger adults in the young group (20 knees). Ultrasonography was performed at rest and during IQE to measure IFP hardness based on shear wave velocity. Near-infrared spectroscopy was performed to measure oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), and total hemoglobin (cHb) in the IFP before (Baseline), during (IQE task), and after IQE (Post). IFP hardness and O2Hb, HHb, and cHb concentration were analyzed using a linear mixed model for the groups and measurement points. RESULTS: During IQE, IFP hardness changes were significantly less in the KOA group than in the other groups (KOA: 95 % confidence intervals (CIs) [-0.854, 0.028]; control: 95 % CI [-0.941, -0.341]; and young: 95 % CI [-2.305, -1.706]). In the KOA group, O2Hb concentration exhibited no significant changes at Post compared with Baseline; however, significant changes were observed in the other groups (KOA: 95 % CI [-1.176, 0.423]; control: 95 % CI [-1.452, -0.276]; and young: 95 % CI [-4.062, -2.102]). CONCLUSIONS: During IQE, changes in hardness and hemoglobin concentration in the IFP were not significant in the KOA group, suggesting impaired local microcirculation of the IFP.

Effect of soft tissue tension around the knee joint on medio-lateral patellar position.

Patellofemoral pain (PFP) is one of the most common sports injuries of the knee joint and has a high persistence and recurrence rate. Medio-lateral patellar position in the knee extension position during contraction is associated with PFP. However, soft tissue tension that most influences the medio-lateral patellar position in the knee extension position during contraction in vivo is unclear. We aimed to clarify the relationship between medio-lateral patellar position and soft tissue tension around the knee joint. Twelve patients with PFP and 20 healthy participants were included. Medio-lateral patellar position and tension of the rectus femoris, vastus lateralis (VL), vastus medialis, iliotibial band (ITB), lateral patellofemoral ligament, and medial patellofemoral ligament were measured during contraction and rest. The tensions of the VL and ITB during contraction and the medio-lateral patellar position at rest were significantly associated with medio-lateral patellar position during contraction (ß = 0.449, 0.354, and 0.393, respectively). In addition, the tension of ITB was significantly associated with the medio-lateral patellar position at rest (ß = 0.646). These relationships were not affected by the presence of PFP. These findings suggest that the patellar position during contraction became more lateral as the tension in the VL and ITB increased, regardless of the presence of PFP. These results may facilitate the prevention and treatment of PFP.

Sensitivity to change and responsiveness of provocative load tests among athletes with patellar tendinopathy.

BACKGROUND: Pain provocation tests are recommended for assessing pain severity and as an outcome measure for individuals with patellar tendinopathy. OBJECTIVE: To evaluate floor and ceiling effects, sensitivity to change, and responsiveness cut-offs of two provocative load tests among athletes with patellar tendinopathy. METHODS: Athletes (N = 41) performed six repetitions for the single leg decline squat (SLDS) and resisted knee extension (KE) at baseline and 12 weeks. Participants rated their pain during each test on a visual analog scale (VAS). Sensitivity to change was assessed by calculating effect size (ES) and the standardized response mean (SRM). The responsiveness cut-offs were assessed using a combination of anchor and distribution- based methods to determine the minimal clinically important difference (MCID) for each test. RESULTS: A floor or ceiling effect was observed in only a small number of participants for both tests except for KE, for which approximately one third of participants had a floor effect at week 12. There was higher sensitivity to change for SLDS (ES: 1.93/SRM: 1.43) compared with KE (ES:0.96/SRM: 1.09). The MCID corresponded to a decrease of 1.6 points for SLDS and 1.0 for KE, while the distribution-based method estimated 1.2 points for SLDS and 1.1 for KE. CONCLUSION: This study found moderate to high sensitivity to change and established MCID values for the SLDS and KE test in athletes with patellar tendinopathy before and after rehabilitation. Both tests may be useful as pain on loading outcomes as athletes progress with their rehabilitation, but the KE test results in higher floor effects and has lower sensitivity to change.

Qualitative and Quantitative Measures in the Infrapatellar Fat Pad in Older Adults: Associations with Knee Pain, Radiographic Osteoarthritis, Kinematics, and Kinetics of the Knee.

RATIONALE AND OBJECTIVES: The purpose of this study is to delineate cross-sectional associations between qualitative and quantitative measures of the infrapatellar fat pad (IPFP) and knee symptoms, structure, kinematics, and kinetics in older adults. METHODS: Ninety eligible subjects (90 knees, mean age 54.0 years, 68.9% female) were examined at our center. We used T2-weighted fat-suppressed magnetic resonance imaging (MRI) to evaluate signal intensity alteration, maximum sagittal area, and depth of the IPFP. Symptomatic osteoarthritis (SOA) was a pain subscale score greater than 0 on the Western Ontario McMaster Osteoarthritis Index. A Kellgren-Lawrence grade ≥ 2 identified incident radiographic osteoarthritis (iROA). Three-dimensional gait data were employed to analyze knee joint kinematics and kinetics. Correlation and regression analyzes assessed associations between IPFP measurements and SOA, iROA, kinematics, and kinetics. RESULTS: There were strong and positive associations between IPFP signal intensity alteration and both SOA and iROA in multivariable regression analyzes [OR (95% CI): 2.849 (1.440 to 5.636), 2.356 (1.236 to 4.492), respectively]. Conversely, a significant negative correlation was observed between IPFP maximum area and flexion angle [B (95%CI): - 1.557 (-2.549 to -0.564)]. Moreover, adjusting for covariates did not reveal any significant correlation between IPFP parameters and other indicators (P > 0.05, respectively). CONCLUSION: IPFP signal intensity alteration and area were associated with knee clinical symptoms, structural abnormalities, and flexion angle in adults over 40, respectively. These findings suggest that IPFP may be a crucial imaging biomarker in early and middle knee osteoarthritis.

The Influence of Femoral Internal Rotation on Patellar Tracking in Total Knee Arthroplasty Using Gap Technique.

BACKGROUD: Femoral internal rotation in total knee arthroplasty (TKA) is well known as one of the main causes of patellar maltracking. Although femoral internal rotation in TKA is considered unacceptable due to the risk of patellar maltracking, it is sometimes required for ligament balancing. We evaluated the influence of femoral internal rotation on patellar tracking in TKA performed using the gap technique. METHODS: From April 2008 to May 2018, 1,612 cases of TKA were done. Among them, 245 cases of TKA for osteoarthritis were followed up for at least 1 year and included in this study. We compared patellar tracking in two groups; group I consisted of 99 cases whose femoral rotation was less than 0° and group II consisted of 146 cases whose femoral rotation was 3°-5° external rotation. Preoperative femoral rotation was measured with the condylar twist angle (CTA) by using computed tomography. The patella was replaced in all cases. Patellar tracking was evaluated with patellar tilt angle (lateral tilt [+] and medial tilt [-]) in the merchant radiograph. Statistical analysis was done using Mann-Whitney U-test. Clinical assessment was performed using the Knee Society clinical rating system. RESULTS: The preoperative CTA was 5.3° ± 1.6° in group I and 5.4° ± 1.6° in group II, showing no statistically significant difference between groups (p = 0.455). Intraoperative femoral rotation was -0.5° ± 0.8° in group I and 3.9° ± 0.8° in group II when the gap technique was used (p < 0.001). The postoperative patellar tilt angle was -0.4° ± 3.6° in group I and 0.1° ± 4.1° in group II with no statistically significant difference (p = 0.251). CONCLUSIONS: Compared with femoral external rotation, femoral internal rotation with ligament balance in TKA was not more associated with patellar maltracking. Therefore, patellar tracking might be related with ligament balance in flexion regardless of the anatomic femoral rotational alignment.

Abstaining from symptomatic implants of modified tension band wiring by nonabsorbable suture fixation for transverse patella fractures.

BACKGROUND: Modified tension band fixation has become commonly used for transverse patella fractures. The conventional stainless steel wire provides sufficient stability but may be associated with complications. OBJECTIVE: The study aimed to evaluate the effectiveness of a new modified tension band fixation technique for transverse patella fractures using a nonabsorbable suture. MATERIAL AND METHODS: We present the result of a prospective series using a nonabsorbable suture (FiberWire) for transverse patella fractures. The mean follow-up period totaled 12 months. A total of 16 patients were evaluated by radiographic and clinical review. The postoperative clinical evaluation employed Lysholm and Böstman scores. RESULT: All clinical results on follow-up were good to excellent. Minimal intra-articular joint stepping and further fracture displacement were recorded. No patient needed re-operation, and functional outcomes of the knee were satisfactory. No significant differences were found between the injured and contralateral knee range of motion. No symptomatic implants and skin complications were noted, and all fractures were completed heal within 15 weeks. CONCLUSION: FiberWire provided sufficient stability and reduced postoperative complications. The results proved appropriate, and the technique has merit, as it obviates the need for re-operation.

Patellar mobility and lower limb kinematics during functional activities in individuals with and without patellar tendinopathy.

STUDY DESIGN: Case-control. OBJECTIVE: To examine whether patients with patellar tendinopathy (PT) display greater patellar mobility and different lower body kinematics than patients without PT. BACKGROUND: PT is a common overuse condition of the patellar tendon that can cause pain and impair function. Subjects with overuse knee problems display different hip and knee functional mechanics, specifically valgus collapse. Patellar hypermobility has not been specifically studied as a possible risk factor for PT. METHODS: 11 patients with PT and 11 controls without PT, age 18 to 40, were studied. Using a patellofemoral arthrometer (PFA), maximal lateral and medial patellar displacement was measured. 3-D motion analysis was performed to determine lower extremity joint motions during single-leg step down and drop vertical jump tests. RESULTS: Patients with PT had significantly increased lateral patellar mobility compared to controls (12.21 ± 3.33 mm vs. 9.19 ± 1.92 mm, P = .017). PT patients showed significantly greater peak hip adduction with both drop vertical jump (2.7° ± 6.3° vs. -5.6° ± 4.2°; P = .003) and step down (17.0° ± 3.8° vs. 12.5° ± 4.4°, P = .024). PT patients demonstrated increased peak ankle external rotation with drop vertical jump (-21.1° ± 5.9° vs. -14.8° ± 5.5°, P = .023) and step down (-15.6° ± 5.5° vs. -9.0° ± 6.0°, P = .017). CONCLUSIONS: Patients with PT exhibit increased lateral patellar mobility, hip adduction, and ankle external rotation. The effects of increased patellar mobility deserve further study in the development, management, and prevention of PT.

Outcomes of Patellar Tendon Imbrication With Distal Femoral Extension Osteotomy for Treatment of Crouch Gait.

BACKGROUND: Crouch gait is a frequent gait abnormality observed in children with cerebral palsy. Distal femoral extension osteotomy (DFEO) with the tightening of the extensor mechanism is a common treatment strategy to address the pathologic knee flexion contracture and patella alta. The goal of this study was to review the results of a patellar tendon imbrication (PTI) strategy to address quadriceps insufficiency in the setting of children undergoing DFEO. METHODS: After institutional review board approval, all patients with crouch gait treated at a single institution with DFEO and PTI were identified. Clinical, radiographic, and instrumented gait analysis data were analyzed preoperatively and at 1 year following surgery. RESULTS: Twenty-eight patients (54 extremities) with a diagnosis of cerebral palsy and crouch gait were included. Significant improvements were appreciated in the degree of knee flexion contracture, quadriceps strength, knee extensor lag, and popliteal angle (P<0.01). Knee flexion at initial contact and during mid-stance improved significantly (P<0.0001), and knee moments in late stance were significantly reduced (P<0.01). The anterior pelvic tilt, however, significantly increased postoperatively (P<0.0001). Radiographic improvements were seen in the knee flexion angle and patellar station as assessed by the Koshino Sugimoto Index (P<0.0001). Four patients (14.2%) developed a recurrence of knee flexion contracture requiring further intervention. CONCLUSIONS: PTI is a simplified and safe technique to address quadriceps insufficiency when performing DFEO. The short-term results of patients who underwent DFEO with PTI demonstrated improvements in clinical, radiographic, and gait analysis variables of the knee. Investigating long-term outcomes, comparing techniques, and assessing quality of life measures are important next steps in research. LEVEL OF EVIDENCE: Level IV-case series.

Quantification of patellar tendon reflex using portable mechanomyography and electromyography devices.

Deep tendon reflexes are one of the main components of the clinical nervous system examinations. These assessments are inexpensive and quick. However, evaluation can be subjective and qualitative. This study aimed to objectively evaluate hyperreflexia of the patellar tendon reflex using portable mechanomyography (MMG) and electromyography (EMG) devices. This study included 10 preoperative patients (20 legs) who had a pathology that could cause bilateral patellar tendon hyperreflexia and 12 healthy volunteers (24 legs) with no prior history of neurological disorders. We attached MMG/EMG sensors onto the quadriceps and tapped the patellar tendon with maximal and constant force. Our results showed a significantly high amplitude of the root mean square (RMS) and low frequency of the mean power frequency (MPF) in the rectus femoris, vastus medialis, and vastus lateralis muscles in both EMG and MMG with both maximal and constant force. Especially in the patients with cervical and thoracic myelopathy, the receiver operating characteristic (ROC) curve for diagnosing hyperreflexia of the patellar tendon showed a moderate to very high area under the curve for all EMG-RMS, EMG-MPF, MMG-RMS, and MMG-MPF values. The use of EMG and MMG for objectively quantifying the patellar tendon reflex is simple and desirable for future clinical applications and could help diagnose neurological disorders.

The Victorian Institute of Sport Assessment Scale for Patellar Tendinopathy (VISA-P): A Reliability Generalization Meta-analysis.

OBJECTIVE: The Victorian Institute of Sport Assessment-Patella (VISA-P) is a questionnaire to assess the severity of patellar tendinopathies. Its use requires good reliability indicators: internal consistency, test-retest and parallel forms. Several studies have been published examining this question, but to date the reliability of this questionnaire (meta-analysis) has not been generalized. The aim of this study was to perform a meta-analysis to generalize the reliability of the VISA-P. DATA SOURCES: MEDLINE, EMBASE, and Scopus. STUDY SELECTION: Studies included were those examining the reliability coefficients of the VISA-P: Cronbach alpha, intraclass correlation coefficient (ICC), and parallel-forms (correlation coefficients compared with other scales). DATA EXTRACTION: All coefficients were extracted and the mean reliability was obtained using fixed- or random-effects models. Sensitivity (leave-one-out analysis) was analyzed. Quality assessment was performed using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. DATA SYNTHESIS: Of 364 scientific articles, 12 fulfilled meta-analysis criteria. The summary statistic was 0.86 [95% confidence interval (CI): 0.78-0.92] for Cronbach alpha and 0.94 (95% CI: 0.89-0.97) for the ICC. Parallel forms depended on the comparative test used, ranging from -0.83 to 0.68. The sensitivity analysis found an influential study for the parallel-forms reliability in the Blazina score. We were unable to analyze the asymmetry of funnel plots and meta-regression models because of the number of studies. CONCLUSIONS: The reliability of VISA-P for assessing the severity of patellar tendinopathies requires greater evaluation with more scientific evidence before it can be implemented in clinical practice.

Osteoarthritic knees have a highly variable patellofemoral alignment: a systematic review.

PURPOSE: This systematic review aimed to evaluate the variability of patellofemoral (PF) alignment and trochlear morphology in osteoarthritic knees. METHODS: PF alignment of the knee was defined by the following parameters: the sulcus angle (SA), femoral trochlear depth (FTD), patellar tilt angle (PTA), lateral patellofemoral angle (LPFA), lateral femoral trochlear inclination (LFTI) and tibial tubercle-trochlear groove distance (TT-TG). The electronic databases MEDLINE and EMBASE were searched from database inception to the search date (February 19, 2019) and were screened for relevant studies. The PRISMA guidelines were followed. Articles reporting PF alignment measurements of osteoarthritic knees in patients over 40 years old were included. Data were extracted and methodological quality was assessed using a 14-item checklist. RESULTS: A total of 8 studies met the inclusion criteria. The studies reported mean values ± SD between 120° and 141.1° ± 7.7 for the SA; 5.8 mm ± 1.4 for the FTD; between - 0.1° ± 3.3 and 10.3° ± 5.7 for the PTA; between 5.8° ± 5.4 and 17° for the LPFA; between 23.2° ± 5.0 and 27.1° ± 4.4 for the LFTI; and 5.8 mm ± 5.4 for the TT-TG. CONCLUSION: PF alignment in the osteoarthritic knee is more variable than expected. This finding should encourage surgeons to consider the individual preoperative PF alignment more precisely with the aim of reducing anterior knee pain (AKP) after TKA. 3D-CT imaging might be of great value to analyse the PF alignment in an appropriate way. LEVEL OF EVIDENCE: Level III.

A Word of Caution for Future Studies in Patellofemoral Pain: A Systematic Review With Meta-analysis.

BACKGROUND: Patellar maltracking is widely accepted as an underlying mechanism of patellofemoral pain. However, methodological differences in the literature hinder our ability to generate a universal quantitative definition of pathological patellofemoral kinematics (patellar maltracking) in patellofemoral pain, leaving us unable to determine the cause of patellofemoral pain. PURPOSE: To systematically review the literature to provide evidence regarding the influence of confounding variables on patellofemoral kinematics. STUDY DESIGN: Systematic review and random effects meta-analysis of control-case studies. METHODS: A literature search of case-control studies that evaluated patellofemoral kinematics at or near full extension and were written in English was conducted using Embase, PubMed, Scopus, and Web of Science up to September 2019. Cases were defined as patients with patellofemoral pain. Studies were eliminated if they lacked quantitative findings; had a primary aim to assess therapy efficacy; or included participants with osteoarthritis and/or previous trauma, pathology, or surgery. A quality assessment checklist was employed to evaluate each study. Meta-analyses were conducted to determine the influence of confounding variables on measures of patellofemoral kinematics. RESULTS: Forty studies met the selection criteria, with quality scores ranging from 13% to 81%. Patient characteristics, data acquisition, and measurement methods were the primary sources of methodological variability. Active quadriceps significantly increased lateral shift (standardized mean difference [SMD]shift = 0.33; P = .0102) and lateral tilt (SMDtilt = 0.43; P = .006) maltracking. Individuals with pain secondary to dislocation had greater effect sizes for lateral maltracking than had those with isolated patellofemoral pain (ΔSMDshift = 0.71, P = .0071; ΔSMDtilt = 1.38, P = .0055). CONCLUSION: This review exposed large methodological variability across the literature, which not only hinders the generalization of results, but ultimately mitigates our understanding of the underlying mechanism of patellofemoral pain. Although our meta-analyses support the diagnostic value of maltracking in patellofemoral pain, the numerous distinct methods for measuring maltracking and the limited control for cofounding variables across the literature prohibit defining a single quantitative profile. Compliance with specific standards for anatomic and outcome measures must be addressed by the scientific and clinical community to establish methodological uniformity in this field.

Kinematic aligned femoral rotation leads to greater patella tilt but similar clinical outcomes when compared to traditional femoral component rotation in total knee arthroplasty. A propensity score matched study.

PURPOSE: External rotation of femoral component in total knee arthroplasty (TKA) with reference to the posterior condyles is recommended in mechanical alignment (MA) to ensure optimum patella tracking. In kinematic knee alignment (KA) technique, femoral component is more internally rotated as the femoral resection is based on flexion-extension axis. This study aims to investigate the clinical and radiological outcomes of the patellofemoral joint in patients who underwent TKA using KA versus mechanical alignment. METHODS: A review of prospectively collected registry data of 378 consecutive cruciate retaining primary TKAs (P.F.C.® Total Knee System, DePuy Synthes, Massachusetts, United States) was performed. Propensity scoring was performed matching patients who received KA TKA (n = 93) to MA TKA (n = 93). Oxford Knee Score (OKS), Knee Society Score (KSS), Short-Form 36 (SF-36), range of motion as well as radiographs assessing patella tilt were compared at 6 months and 2 years after surgery. All patients received the same implant and had their patella resurfaced. RESULTS: OKS, KSS, physical component of SF-36 and satisfaction rates were comparable at both 6 months and 2 years after surgery. There was moderate association between preoperative and postoperative patella tilt in KA TKA (Cramer's V = 0.260, p < 0.05). Postoperatively, KA group had a greater number of patients with lateral patella tilt compared to the mechanical group (12 [12.9%] vs 1 [1.1%], p < 0.001). Patella tilts, however, resolved two years after surgery. CONCLUSION: The relative internal rotation of the femoral component in KA TKA results in greater incidence of lateral patella tilt postoperatively. Nevertheless, patella tilt resolution was noted at 2 years. LEVEL OF EVIDENCE: Level III Evidence-Retrospective Cohort Study.

Isolated MPTL reconstruction fails to restore lateral patellar stability when compared to MPFL reconstruction.

PURPOSE: To biomechanically evaluate MPTL reconstruction and compare it with two techniques for MPFL reconstruction in regard to changes in patellofemoral contact pressures and restoration of patellar stability. METHODS: This is an experimental laboratory study in eight human cadaveric knees. None had patellofemoral cartilage lesions or trochlear dysplasia as evaluated by conventional radiographs and MRI examinations. The specimens were secured in a testing apparatus, and the quadriceps was tensioned in line with the femoral shaft. Contact pressures were measured using the TekScan sensor at 30°, 60° and 90°. The sensor was placed in the patellofemoral joint through a proximal approach between femoral shaft and quadriceps tendon to not violate the medial and lateral patellofemoral complex. TekScan data were analysed to determine mean contact pressures on the medial and lateral patellar facets. Patellar lateral displacement was evaluated with the knee positioned at 30° of flexion and 9 N of quadriceps load, then a lateral force of 22 N was applied. The same protocol was used for each condition: native, medial patellofemoral complex lesion, medial patellofemoral ligament reconstruction (MPFL-R) using gracilis tendon, MPFL-R using quadriceps tendon transfer, and medial patellotibial ligament reconstruction (MPTL-R) using patellar tendon transfer. RESULTS: No statistical differences were found for mean and peak contact pressures, medial or lateral, among all three techniques. However, while both techniques of MPFL-R were able to restore the medial restraint, MPTL-R failed to restore resistance to lateral patellar translation to the native state (mean lateralization of the patella [mm]: native: 9.4; lesion: 22; gracilis MPFL-R: 8.1; quadriceps MPFL-R: 11.3; MPTL-R: 23.4 (p < 0.001). CONCLUSION: MPTL-R and both techniques for MPFL-R did not increase patellofemoral contact pressures; however, MPTL-R failed to provide a sufficient restraint against lateral patellar translation lateral translation in 30° of flexion. It, therefore, cannot be recommended as an isolated procedure for the treatment of patellar instability.

The quadriceps insertion of the medial patellofemoral complex demonstrates the greatest anisometry through flexion.

PURPOSE: A comprehensive understanding of the biomechanical properties of the medial patellofemoral complex (MPFC) is necessary when performing an MPFC reconstruction. How components of the MPFC change over the course of flexion can influence the surgeon's choice of location for graft fixation along the extensor mechanism. The purpose of this study was to (1) determine native MPFC length changes throughout a 90° arc using an anatomically based attachment and using Schöttle's point, and (2) compare native MPFC length changes with different MPFC attachment sites along the extensor mechanism. METHODS: Eight fresh-frozen (n = 8), cadaveric knees were dissected of all soft tissue structures except the MPFC. The distance between the femoral footprint (identified through anatomical landmarks and Schottle's point) and the MPFC was calculated at four attachment sites along the extensor mechanism [midpoint of the patella [MP], the center of the osseous footprint of the MPFC (FC), the superomedial corner of the patella at the quadriceps insertion (SM), and the proximal extent of the MPFC along the quadriceps tendon (QT)] at 0°, 20°, 40°, 60°, and 90° of flexion. RESULTS: Length changes were investigated between the MPFL femoral attachment site and the radiographic surrogate of the MPFL attachment site, Schottle's Point (SP). Paired t tests at each of the four components showed no differences in length change from 0° to 90° when comparing SP to the anatomic MPFC insertion. MPFL length changes from 0° to 90° were greatest at the QT point (13.9 ± 3.0 mm) and smallest at the MP point (2.7 ± 4.4 mm). The FC and SM points had a length change of 6.6 ± 4.2 and 9.0 ± 3.8, respectively. Finally, when examining how the length of the MPFC components changed through flexion, the greatest differences were seen at QT where all comparisons were significant (p < 0.01) except when comparing 0° vs 20° (n.s.). CONCLUSION: The MPFC demonstrates the most significant length changes between 0° and 20° of flexion, while more isometric behavior was seen during 20°-90°. The attachment points along the extensor mechanism demonstrate different length behaviors, where the more proximal components of the MPFC display greater anisometry through the arc of motion. When performing a proximal MPFC reconstruction, surgeons should expect increased length changes compared to reconstructions utilizing distal attachment sites.

The Benefit of Perineural Injection Treatment with Dextrose for Treatment of Chondromalacia Patella in Participants Receiving Home Physical Therapy: A Pilot Randomized Clinical Trial.

Introduction: Chondromalacia patella is the degeneration of articular cartilage on the posterior facet of the patella and may indicate the onset of osteoarthritis. Conservative management is the main treatment option, and surgical intervention is considered the last option in a small percentage of patients. Perineural Injection Treatment (PIT) is a recently developed treatment option that is directed adjacent to the peripheral nerves that are the source of pathology causing neurogenic inflammation and pain. Objective: The objective of this study was to evaluate the efficacy of PIT combined with a home physical therapy program in patients with a diagnosis of chondromalacia patella compared with a control group receiving physical therapy only. Methods: Two patient groups were involved in this randomized clinical trial. The first received PIT combined with physical therapy (PIT + PT group) and the second was managed with physical therapy alone (PT group). Both groups were indicated to follow a 6-week home therapy plan afterward. The Western Ontario and McMaster Osteoarthritis Index was used to assess the patients at baseline and 6 months after therapy interventions. Results: Fifty patients (38 women and 12 men, median age 54.7 ± 14.8 years) were included; sex distribution and age did not differ between groups. Both groups had chondromalacia grade II or III, but the degree of gonarthrosis did not differ significantly between groups. The PIT + PT group outperformed PT group for pain (7.3 ± 3.5 vs. 3.2 ± 2.9 points; p < 0.010), stiffness (3 ± 1.69 vs. 1.6 ± 1.5 points; p < 0.010), and functional capacity (23.2 ± 10.7 vs. 11.1 ± 8.9 points; p < 0.010). Conclusions: Compared with physical therapy alone, PIT plus physical therapy reduced pain and stiffness and restored functional capacity. ClinicalTrials.gov Register Number #NCT03515720.

Predictors for an unsuccessful conservative treatment of patients with medial patellar plica syndrome.

INTRODUCTION: In several cases persistent medial knee pain remains after conservative treatment in patients with medial patellar plica syndrome. In recent literature accepted criteria for surgical indication are lacking. In this retrospective study patients after conservative treatment were evaluated to identify predictors for an unsuccessful outcome. MATERIALS AND METHODS: 117 Patients with medial patellar plica syndrome between 2016 and 2019 were retrospectively evaluated. All patients received conservative treatment for three months. Surgery was indicated due to failed conservative treatment (n = 76) with persistent medial knee pain and restriction of activity after 3 months. Preoperative MRI analysis, Lysholm score, pain by the visual analog scale (VAS), postoperative sports participation (RTS) and Tegner activity score were collected at least 12 months after definite treatment. Statistical analysis was performed to evaluate differences between patients with successful and unsuccessful conservative treatment. RESULTS: There were significant differences in the clinical and radiological findings between patients with successful and unsuccessful conservative treatment. Patients with failed conservative treatment showed a significant larger diameter of the medial patellar plica (0.8 ± 0.3 mm vs. 1.6 ± 0.4 mm; p < 0.05) and a significant higher rate of contact of the plica to the adjacent cartilage. Furthermore, these patients reported a significant higher rate of medial knee pain from flexion to extension and snapping symptoms. At final follow-up the patient-reported outcome by means of Lysholm score (96.25 vs. 95.93), RTS (96.2% vs. 97%) and Tegner activity score (6.0 vs. 6.01) was excellent after conservative and surgical treatment. There were no statistical differences in the preoperative and postoperative outcomes between both. CONCLUSIONS: The diameter of a medial patellar plica and contact of the plica to the retropatellar cartilage as well as clinical signs like persistent medial knee pain from flexion to extension with snapping symptoms might be predictors for an unsuccessful conservative treatment and the need for surgical intervention in patients with painful medial patellar plica syndrome.

Development of an innovative measurement method for patellar tracking disorder.

In this study, we investigated whether the measurement of patellar tracking can be used as a diagnostic parameter of patellofemoral joint disease. Patellar tracking is defined as the movement of the patella in relation to the femorotibial joint within the full range of flexion and extension of the knee joint. The PubMed, EMBASE, Medline, PsychINFO, and AMED databases were used to find relevant articles. Analyzed were the patellar tracking coordinate system and the measurement objects, precision, methods used in those studies, as well as the results obtained. Origin points for coordinate systems varied across the studies. The research object and methods of patellar tracking varied in the studies. Most studies focused on a static description of the internal and external displacement and the internal and external inclination. The in vivo, noninvasive, and six degrees of freedom evaluation of patellar tracking reflect patellar motion more comprehensively, though each of these methods does so in different ways. Dynamic and quantitative evaluation of patellar tracking is still lacking in clinical work. Accurate and quantitative patellar tracking measurement could provide clinicians with a comprehensive evaluation of the stability of the knee joint.

Comparison of the Therapeutic Effects of Tension Band with Cannulated Screw and Tension Band with Kirschner Wire on Patella Fracture.

BACKGROUND: Patella fracture accounts for 1% of bone injury, of which anatomical reduction is of great significance to the recovery. Tension band with cannulated screw and Kirschner wire is commonly used methods for the treatment of displaced patella fracture. However, there is still some controversy on the clinical efficacy of the two treatment methods. OBJECTIVE: This study aimed at comparing the therapeutic effects of the cannulated screw and Kirschner wire tension bands on patella fracture and at providing more data basis for clinical selection of treatment methods for patella fracture. METHODS: Altogether, 146 patients with displaced patella fracture admitted to our hospital from March 2016 to February 2018 were selected and divided into two groups according to the different treatment methods. Among them, 71 patients received tension band with a cannulated screw (TBWCS group) and 75 patients received tension band with Kirschner wire (TBWKW group). Two groups of patients were compared in terms of surgical treatment effect after one year of treatment, complications within six months after the operation and operation-related indexes. The pain visual analogue scale (VAS) score, knee flexion degree, Lysholm score, and Bostman score were recorded at 1, 3, 6, and 12 months after operation, and the activity of daily living scale (ADL) score was evaluated at the last follow-up. RESULTS: During the operation of patella fracture patients, the intraoperative blood loss, hospitalization time, and knee flexion loss of patients in TBWCS group were less than those in the TBWKW group (P < 0.05), the starting time of postoperative functional exercise was earlier than that of patients in TBWKW group (P < 0.05), and the incidence rate of secondary operation was lower than that of patients in the TBWKW group (P < 0.05), but there was no statistical difference in the operation time, incision length, and postoperative fracture gap between the two groups. The results of curative effect analysis showed that the knee flexion, Lysholm score, and Bostman score of patients treated with tension band with cannulated screw were higher than those treated with Kirschner wire (P < 0.05), and VAS score was lower. Tension band with cannulated screw had a better curative effect on patella fracture (P < 0.05), lower complication rate (P < 0.05), and higher quality of life of patients (P < 0.05). CONCLUSION: Tension band with cannulated screw has a good curative effect on patella fracture, low incidence of complications, early start of postoperative functional exercise, and high quality of life.

Patella Alta in Ambulatory Children With Cerebral Palsy: Prevalence and Functional Significance.

BACKGROUND: Gait dysfunction associated with patella alta (PA) in subjects with cerebral palsy (CP) has been presumed but not objectively established clinically or through biomechanical modeling. It is hypothesized that PA is associated with increasing level of motor impairment, increasing age, obesity, and worse stance phase knee kinematics and kinetics in children with CP. METHODS: Retrospective case series of 297 subjects with CP studied in our Motion Analysis Center. Data analyzed included patient demographics (age, body mass index, CP classification), patella height (Koshino-Sugimoto Index), and knee kinematics and kinetics. RESULTS: PA was present in 180 of 297 subjects (61%), in 68 of the 146 (47%) with unilateral CP, and 112 of 151 subjects (74%) with bilateral CP. For unilateral CP, the prevalence of PA was not significantly different between Gross Motor Function Classification System (GMFCS) I and II (P=0.357). For bilateral CP, the prevalence of PA in GMFCS III was significantly greater than in GMFCS I and II (P=0.02). Regression analysis showed a significant trend between increasing age and PA in unilateral and bilateral groups (P<0.001 and 0.001, respectively). The prevalence of PA was not significantly different across body mass index categories for either unilateral or bilateral groups. There were only 2 of 10 significant correlations between PA and gait parameters for subjects with unilateral CP functioning at the GMFCS I and II levels. There were 8 of 12 significant correlations between PA and gait parameters for subjects with bilateral CP functioning at the GMFCS I, II, and III levels. CONCLUSIONS: PA is common in ambulatory children with CP across topographic types and motor functional levels. PA is well tolerated with respect to gait dysfunction in unilateral CP, but may contribute to crouch gait in bilateral CP. Gait dysfunction cannot be inferred from the radiographic assessment of patellar height, and radiographic evidence of PA by itself does not justify surgical correction with patellar tendon advancement or shortening. LEVEL OF EVIDENCE: Level III-prognostic, retrospective series.