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.

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.

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.

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 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.

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.

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.

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.

Patellar Malalignment Is Associated With Patellofemoral Lesions and Cartilage Relaxation Times After Hamstring Autograft Anterior Cruciate Ligament Reconstruction.

BACKGROUND: There is growing evidence suggesting a link between patellofemoral joint (PFJ) osteoarthritis in anterior cruciate ligament (ACL)-reconstructed knees and altered joint alignment. PURPOSE: To determine whether patellar alignment differs between participants with and without ACL reconstruction (ACLR) and to identify possible associations between patellar alignment and PFJ osteoarthritis features over 3 years. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 37 participants with ACLR (sex, 23 male; mean ± SD age, 28.1 ± 7.4 years) and 20 healthy controls (13 male; 30.4 ± 4.8 years) participated. Patients underwent magnetic resonance imaging: (1) sagittal T2-weighted fat-saturated fast spin echo images to calculate patellar alignment, (2) sagittal 3-dimensional intermediate-weighted fast spin echo Cube sequence for clinical morphological grading (modified Whole-Organ Magnetic Resonance Imaging Score [WORMS]), and (3) sagittal combined T1ρ/T2 mapping sequence for performing voxel-based relaxometry. Patellar alignment of the ACLR knees were assessed at 6 months (baseline). One-way analysis of variance was used to compare patellar alignment among the ACLR (at 6 months), contralateral, and control knees. Within the ACLR group, a logistic regression model was used to identify if patellar alignment measures at baseline were risk factors for worsening of PFJ structural changes over 3 years. Statistical parametric mapping was used to evaluate the longitudinal associations between patellar alignment and cartilage relaxation times at 3 years. RESULTS: When compared with control knees, ACLR knees exhibited a laterally and anteriorly displaced patella (P = .045 and P = .041), less flexion (P = .031), and less lateral spin (P = .012). Furthermore, excessive lateral displacement was a significant predictor of worsening of WORMS (P = .050). Lateral displacement was positively correlated with increased T1ρ and T2 in the patellar and trochlear cartilage at 3 years. Patellar lateral spin revealed similar negative findings. CONCLUSION: Participants with ACLR exhibited a laterally and anteriorly displaced patella, less flexion, and less lateral spin when compared with healthy controls. Excessive patellar lateral displacement was the strongest predictor to the development of PFJ osteoarthritis features longitudinally.

Association of Knee Pain and Crouch Gait in Individuals With Cerebral Palsy.

BACKGROUND: Crouch gait (ie, excessive knee flexion) is commonly seen in patients with cerebral palsy (CP) and has been inconsistently linked with knee pain. The definitive cause of knee pain is unknown, but may result from increased joint forces due to crouch gait kinematics. Our purpose was to determine whether knee pain is positively associated with knee flexion in gait among a large sample of ambulatory individuals with CP. We hypothesized that knee pain prevalence would increase as knee flexion increased. METHODS: In this retrospective study, pain questionnaire and 3-dimensional gait analysis data from 2015 to 2018 were extracted from the medical records of individuals with CP who had a clinical gait analysis. The pain questionnaire asked caregivers/patients to indicate the location of pain and when it occurs. A multivariate logistic regression was performed with minimum knee flexion in stance, patella alta, age, and sex as predictors of knee pain. RESULTS: Among the 729 participants included in the analysis, 147 reported knee pain (20.1%). The odds of knee pain were not associated with minimum knee flexion in stance or sex. However, the odds of knee pain increased 73.2% when patella alta was present (P=0.008) and tended to increase 2.2% as age increased (P=0.059). CONCLUSIONS: The data suggest that there is not a meaningful association between crouch gait and knee pain. Having patella alta was associated with pain. Further studies that use validated pain questionnaires are needed to understand the multifactorial etiology of knee pain within ambulatory individuals with CP. LEVEL OF EVIDENCE: Level III-case-control study.

Reliability of Vibroarthrography to Assess Knee Joint Sounds in Motion.

Knee acoustic emissions provide information about joint health and loading in motion. As the reproducibility of knee acoustic emissions by vibroarthrography is yet unknown, we evaluated the intrasession and interday reliability of knee joint sounds. In 19 volunteers (25.6 ± 2.0 years, 11 female), knee joint sounds were recorded by two acoustic sensors (16,000 Hz; medial tibial plateau, patella). All participants performed four sets standing up/sitting down (five repetitions each). For measuring intrasession reliability, we used a washout phase of 30 min between the first three sets, and for interday reliability we used a washout phase of one week between sets 3 and 4. The mean amplitude (dB) and median power frequency (Hz, MPF) were analyzed for each set. Intraclass correlation coefficients (ICCs (2,1)), standard errors of measurement (SEMs), and coefficients of variability (CVs) were calculated. The intrasession ICCs ranged from 0.85 to 0.95 (tibia) and from 0.73 to 0.87 (patella). The corresponding SEMs for the amplitude were ≤1.44 dB (tibia) and ≤2.38 dB (patella); for the MPF, SEMs were ≤13.78 Hz (tibia) and ≤14.47 Hz (patella). The intrasession CVs were ≤0.06 (tibia) and ≤0.07 (patella) (p < 0.05). The interday ICCs ranged from 0.24 to 0.33 (tibia) and from 0 to 0.82 (patella) for both the MPF and amplitude. The interday SEMs were ≤4.39 dB (tibia) and ≤6.85 dB (patella) for the amplitude and ≤35.39 Hz (tibia) and ≤15.64 Hz (patella) for the MPF. The CVs were ≤0.14 (tibia) and ≤0.08 (patella). Knee joint sounds were highly repeatable within a single session but yielded inconsistent results for the interday reliability.

Immediate effects of an elastic patellar brace on pain, neuromuscular activity and knee kinematics in subjects with patellofemoral pain.

INTRODUCTION: The aim of this randomized controlled trial was to investigate immediate effects of a patellar brace on pain, neuromuscular activity, and knee kinematics in subjects with patellofemoral pain syndrome. MATERIALS AND METHODS: Fifty subjects with a diagnosis of patellofemoral pain syndrome completed 6 activities each with and without a patellar brace in a randomized order. The subjects were asked to rate their perceived pain on a Visual Analog Scale after each activity. During the activities, neuromuscular activity of vastus medialis and vastus lateralis, as well as knee angles were measured. RESULTS: Subjects showed a statistically significant pain reduction of 33-56% on the Visual Analog Scale during all activities while wearing the brace. Two groups with different onset patterns for vastus medialis and vastus lateralis were identified: one group who activated vastus medialis prior to vastus lateralis, and one who activated vastus medialis after vastus lateralis. In the subgroup of subjects activating vastus lateralis prior to vastus medialis, bracing resulted in a significantly (p = 0.048) earlier onset of vastus medialis by 56 ms. In all but one activity, the vastus medialis/vastus lateralis ratio without the patellar brace was < 1.0 and inverted with the patellar brace > 1.0. Knee angles in the sagittal plane increased significantly with the patellar brace in two activities. CONCLUSION: Patellofemoral bracing results in an immediate decrease of pain, an earlier onset of vastus medialis and inverted vastus medialis/vastus lateralis ratio and altered knee kinematics.