Role of Anatomical Patella Replacement on Anterior Knee Pain

Background

Anterior knee pain (AKP) remains a complex issue affecting patient satisfaction after total knee arthroplasty. Several radiographic parameters have been shown to be causative factors with various designs. The aim of this study is to evaluate the known radiographic parameters of AKP and clinical outcomes (ie, AKP) in the setting of a modern prosthesis with an anatomic patella button.

Mechanical Properties of the Human Tibial and Peroneal Nerves Following Stretch With Histological Correlations

Despite the extensive literature regarding peripheral nerve stretch injuries, there are few studies that compare the nerve histology with the mechanical properties in humans. There is clinical evidence suggesting that the peroneal nerve is at greater risk for injury compared to the tibial nerve following total hip arthroplasty and hip trauma. We examined the two nerves from fresh human cadavers with or without controlled stretch. The mechanical properties, stiffness, and strain were compared with light microscopic preparations in longitudinal sections stained by the trichrome method for collagen and showing the effects of structural deformation. The tibial nerve had an average failure load 1.7× that for the peroneal nerve (P = 0.0001). Although the corresponding average stiffness showed a trend toward being larger (4.39 vs. 3.81 N/mm), the difference was not significant (P = 0.126). Histologically, the perineurium along with the underlying nerve fascicle was undulated in the control specimens and straightened out in the stretched specimens. Peroneal nerves went on to failure at lower loads and exhibited a wavy pattern on pathologic slides after failure, which shows that peroneal nerves fail mechanically before they can unfold. The tibial nerve has a biomechanical and histological advantage compared to the peroneal nerve during tensile testing, which could be the reason why it is less commonly damaged. We conclude that the perineurium is especially protective against deformation changes in human nerves relative to the respective nerve size and number of fascicles. Anat Rec, 302:2030–2039, 2019. © 2019 American Association for Anatomy     

Residual varus alignment after total knee arthroplasty increases knee adduction moment without improving patient function: A propensity score-matched cohort study

BackgroundTargeting residual varus alignment in total knee arthroplasty may be functionally beneficial to preoperative varus patients.MethodsBilateral TKA patients were enrolled. According to the postoperative hip-knee-ankle axis, patients were allocated into residual varus (3° ± 1°) alignment group or neutral (0° ± 1°) alignment group. Then, 1:2 propensity score matching was used to match preoperative variables. Finally, matched neutral (n = 45) and varus groups (n = 32) were followed-up for two years and compared. The primary outcome was the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes were range of motion (ROM), Knee Society knee score and function score, spatiotemporal gait parameters, dynamic alignment, knee flexion angle, knee adduction moment (KAM) and internal knee extension moment.ResultsAt two years after surgery, the mean difference of WOMAC score was 0.3 (95% CI, [? 3.1, 3.7]) between the two groups. All secondary outcomes, except KAM and dynamic alignment, showed no significant difference between the two groups. Residual varus alignment group showed increased KAM and maximum KAM was 19% higher (P = 0.006).ConclusionsResidual varus alignment showed no clinical benefits, and both groups of patients had a functionally identical knee gait biomechanics, except for increased KAM and varus alignment. The authors consider that even in patients with varus alignment, the first principle is still achieving neutral alignment, which is helpful for reducing the KAM.Level of evidenceIII, retrospective cohort study.     

The midterm results of a cohort study of patellofemoral arthroplasty from a non-designer centre using an asymmetric trochlear prosthesis

PurposePatellofemoral arthroplasty (PFA) prosthesis with asymmetric trochlear component was introduced as an improvement from existing designs for surgical treatment of symptomatic isolated patellofemoral arthritis. The purpose of this study was to evaluate midterm results in patients who underwent PFA procedure using such prosthesis.MethodsOur study involved a continuous retrospective cohort of patients who underwent PFA using Journey PFA prosthesis with an asymmetric trochlear component, performed between June 2007 and July 2016 at a non-designer centre. The Patient Reported Outcome Measures and patient satisfaction questionnaires were collected for final evaluation.ResultsA total of 103 PFA performed on 79 patients were evaluated. Median age at the time of surgery was 58 years (range 42 to 78 years); the mean follow-up period was 6 years (range 2 to 11 years). Four knees were revised to Total Knee Arthroplasty for reasons not related to the implant. The cumulative survival estimated by the Kaplan–Meier method was 94.3% (95% confidence interval: 88.4%–100%). There were statistically significant improvements in functional outcome scores.ConclusionThis series of patients who underwent PFA with the asymmetric trochlear component has shown promising mid-term results with no implant-related complications.     

外侧半月板后根部损伤不同缝合位置对膝关节生物力学的影响

目的对损伤的外侧半月板后根部进行不同位置的修复固定,比较不同缝合方式时膝胫股关节的生物力学结果,探讨外侧半月板后根部损伤最佳缝合术式。方法使用8例人体尸体膝关节,胫腓骨固定装置维持膝关节在0°位,在1 k N压缩载荷下,采用Tek-scan压力感测片收集膝关节外侧半月板后根部完整、外侧半月板后根部断裂、将外侧半月板后根部分别缝合至中心点、中心点偏后5 mm、中心点偏前5 mm、中心点偏外5 mm位置下的平均接触压力、峰值压力以及接触面积。结果在外侧间室,与完整状态相比半月板后根部损伤断裂后会导致平均接触压力和峰值压力明显增加(P0. 01),接触面积减少(P0. 05)。4种缝合固定方法均可减少平均压力和峰值接触压力,接触面积较根部断裂时均有增加。在半月板后根部中心点偏外5 mm缝合时,生物力学结果更接近完整膝关节(P0. 05)。比较缝合位点在根部中心点和中心点偏后5 mm时,平均接触压力影响差别微小,峰值接触压力、接触面积均无统计学差异(P0. 05)。在内侧间室,生物力学指标各组间均无统计学差异(P0. 05)。结论外侧半月板后根部发生撕裂后会导致膝关节外侧间室的平均接触压力、峰值压力以及接触面积相比正常膝关节发生显著改变;半月板缝合位置在原根部中心点偏外5 mm时,其生物力学功能更接近完整膝关节。     

不同屈膝肌群和伸膝肌群肌力比值的等速肌力训练治疗脑卒中后膝过伸的疗效评价

设置不同的屈膝肌群与伸膝肌群肌力比值参数,观察应用等速肌力训练纠正脑卒中后膝过伸患者的疗效,为该病的治疗提供依据。     

Outcomes of single-level cervical disc arthroplasty versus anterior cervical discectomy and fusion

Several studies have established the short-term safety and efficacy of cervical disc arthroplasty (CDA) as compared to anterior cervical discectomy and fusion (ACDF). However, few single-center comparative trials have been performed, and current studies do not contain large numbers of patients. We retrospectively reviewed all patients from a single military tertiary medical center between August 2008 to August 2012 who underwent single-level CDA or single-level ACDF and compared their clinical outcomes and complications. A total of 259 consecutive patients were included in the study, 171 patients in the CDA group with an average follow-up of 9.8 (±9.9) months and 88 patients in the ACDF group with an average follow-up of 11.8 (±9.6) months. Relief of pre-operative symptoms was 90.1% in the CDA group and 86.4% in the ACDF group with rates of return to full pre-operative activity of 93.0% and 88.6%, respectively. Patients who underwent CDA had a higher rate of persistent posterior neck pain (15.8% versus 12.5%), and patients who underwent ACDF were at risk for symptomatic pseudarthrosis at a rate of 3.4%. Reoperation rates were higher in the ACDF group (5.7% versus 3.5%). To our knowledge, this review is the largest, non-funded, comparison study between single-level CDA and single-level ACDF. This study demonstrates that CDA is a safe and reliable alternative to ACDF in the treatment of cervical radiculopathy and myelopathy resulting from spondylosis and acute disc herniation.     

Comparison of patient reported outcomes after Triathlon? and Kinemax Plus prostheses

INTRODUCTION

The Triathlon^® (Stryker, Kalamazoo, MI, US) total knee replacement was designed to improve patient function and survivorship. The aim of this study was to determine whether the Triathlon^® prosthesis produces better patient reported outcomes than a previous design by the same manufacturer, the Kinemax Plus.

METHODS

The outcome of 233 knees of patients with a mean age of 68 years (range: 40–80 years) who received the Kinemax Plus prosthesis were compared with the outcomes of 220 knees of patients with a mean age of 70 years (range: 42–90 years) who received the Triathlon^® prosthesis. Data were collected via postal questionnaire prior to surgery as well as at 8–12 weeks and at 1 year following surgery. Validated questionnaires were used including the WOMAC^® (Western Ontario and McMaster Universities) pain and function scales, the Knee injury and Osteoarthritis Outcome Score quality of life scale and the self-administered patient satisfaction scale.

RESULTS

This study found that patients who had the Triathlon^® prosthesis had significantly better pain relief (p<0.0001), function (p=0.028), knee related quality of life (p<0.0001) and satisfaction (p=0.0003) at three months after surgery than those who received the Kinemax Plus prosthesis. In addition, knee related quality of life (p=0.002) and satisfaction (p=0.021) were significantly higher at one year after surgery in Triathlon^® patients.

CONCLUSIONS

The findings suggest that return to function and reduction in pain may occur more quickly in patients with a Triathlon^® prosthesis than in those with the Kinemax Plus.