Carsten O. Tibesku

Intraarticular Hyaluronic Acid versus Glucocorticoid Injections for Nonradicular Pain in the Lumbar Spine

PURPOSEnTo investigate the efficacy and safety of intraarticular sodium hyaluronate (SH) compared with intraarticular glucocorticoids (triamcinolone acetonide; TA) in the treatment of chronic nonradicular lumbar pain.nnnMATERIALS AND METHODSnSixty patients were included in this randomized, controlled, blind-observer clinical study and randomly assigned to two groups to receive 10 mg SH or 10 mg TA per facet joint. The facet joints on both sides at levels S1-L5, L5-L4, and L4-L3 were treated once per week under computed tomographic guidance. The study visits were timed to permit assessment of the immediate effect as well as possible carryover effects at 3 and 6 months after completion of treatment. Changes in pain were assessed with a visual analog scale (VAS) and changes in function and quality of life were assessed by the Roland Morris Questionnaire (RMQ), the Oswestry Disability Questionnaire (ODQ), the Low Back Outcome Score (LBOS), and the Short Form 36 (SF-36) questionnaire.nnnRESULTSnPatients reported lasting pain relief, better function, and improved quality of life with both treatments. Mann-Whitney analyses of the patient questionnaires (RMQ, ODQ, and LBOS) very consistently showed that SH is not inferior to TA. In addition, the efficacy of SH was largely comparable with that of TA on the VAS and SF-36. No adverse effects were reported after administration of the test products. The intraarticular treatment of facet joints (levels S1-L5, L5-L4, and L4-L3) with SH in patients with chronic nonradicular pain in the lumbar spine resulted in a marked reduction in pain with improved function and better quality of life, which was at least equal to the effect of a course of TA injections. SH-treated patients showed greater benefits in the long term.nnnCONCLUSIONnIntraarticular SH is a very promising new option for the treatment of patients with chronic nonradicular lumbar symptoms.

Clinical and functional comparison of uni- and bicondylar sledge prostheses

The aim of the present study was the evaluation of differences in clinical results, proprioceptive performance and gait in patients with unicondylar and bicondylar sledge prostheses of the knee. In a retrospective study, 17 patients with unicondylar sledge prostheses were compared with 15 patients with bicondylar sledge prostheses. Clinical examination was rated using HSS, Knee Society, and patellar scores and a visual analogue scale for pain. Proprioceptive performance was examined using sway measurements during single leg stance on a force platform. In addition, the patients underwent 3-D gait analysis including measurements of ground reaction forces and surface electromyographic (EMG) investigation of the lower extremity. Comparing both patient groups in clinical scores, gait, EMG and proprioception, no significant differences were found. Implantation of bicondylar sledge prostheses retaining both cruciate ligaments achieves functional results as good as unicompartmental arthroplasty. The presented results might encourage future research on new models of total joint replacement with preservation of both cruciate ligaments.

Differences in patellofemoral contact stresses between mobile-bearing and fixed-bearing total knee arthroplasties: a dynamic in vitro measurement

IntroductionAnterior knee pain is one of the most common problems after total knee arthroplasty (TKA). Mobile-bearing designs should improve patella tracking with a reduced rate of patella tilt as well as reduced patellofemoral contact stresses and improve knee flexion. The aim of this dynamic in vitro investigation was to evaluate the changes of patellofemoral contact stresses after TKA using fixed and mobile-bearing designs.Materials and methodsSeven knee specimens were mounted into a knee simulator imitating an isokinetic extension of the knee. The patellofemoral contact was measured before and after tricompartimental TKA with fixed and mobile-bearing designs using pressure-sensitive films. Contact stresses were measured from 120° knee flexion to full extension with a simulated force of the quadriceps muscle up to 1,200xa0N. Additionally all measurements were performed with simulated co-contraction of the hamstrings muscles.ResultsFixed-bearing TKA increases patellofemoral contact stresses compared to physiologic conditions. After patella resurfacing, contact stresses increase even more. By changing the prosthesis design to mobile bearing, maximum contact stress was measured to be punctual higher than in fixed-bearing implants. In the interval between 0°–30° and 70°–105° of flexion, obviously lower pressures were evaluated for the mobile-bearing design. With cocontraction of the hamstrings, a lower contact stress of the mobile-bearing design was evident for the complete measurement of the knee extension.ConclusionAn increase of patellofemoral contact stresses after patellar resurfacing in TKA could be demonstrated. This outcome implicates a higher risk of patellofemoral complications. The mobile-bearing design showed evidently lower patellofemoral contact stresses than the fixed-bearing design.

Clinical and functional results after the rehabilitation period in minimally-invasive unicondylar knee arthroplasty patients

The objective of the present study was to analyze the clinical and functional outcome after minimally-invasive implantation of a Repicci-type unicompartmental sledge prosthesis . In 29 patients with primary unicompartmental knee osteoarthritis, 29 replacements of the medial compartment and four of the lateral compartment were performed using the minimally-invasive technique with the metal-backed and the all-polyethylene versions of the Repicci sledge prosthesis. Electromyography (EMG) of standardized locations was measured with the MyoSystem 2000 and analyzed with Myoresearch software. Gait analysis was performed with a six-camera motion analysis system and force platforms. Established clinical and quality of life (SF-36) scores were used to compare patients with 11 healthy age-matched individuals. The Repicci sledge prosthesis led postoperatively to functional results that were in the range of healthy joints, and superior to sledge prostheses of a different design. Gait and balance parameters were comparable to the control group, whilst electromyographically lower amplitudes were found in the patients than the controls and in the operated legs as compared to the non-operated legs. Many parameters of quality of life and activity were comparable to age-matched healthy individuals, and quality of life was superior to total knee replacement. When implanted using a minimally-invasive technique and with suitable patient selection, the Repicci sledge led to functional results comparable to those of healthy joints and gait parameters comparable to those of healthy individuals. The level of evidence is Level III, retrospective cohort study.

Retropatellar contact characteristics before and after total knee arthroplasty

PURPOSEnQualitative analysis of the retropatellar contact characteristics after total knee arthroplasty.nnnMATERIAL AND METHODSnSix cadaveric knees were investigated before and after implantation of a Genesis I knee prosthesis without and with patellar resurfacing in different positions. Joint contact characteristics were evaluated with Fuji Prescale film type Super Low and analyzed qualitatively in nine quadrants. The pressure was determined from a 5-s loading duration in four different knee positions between 45 degrees and 120 degrees of flexion. The femoral component of the prosthesis was implanted in neutral as well as in internal and external rotation. A quadriceps force of 280 N with either a predominant medial or lateral pulling direction was applied.nnnRESULTSnWithout prosthesis the largest contact area is between 60 degrees and 90 degrees of flexion. A lateral muscle force direction as well as an external rotation increased the frequency of loading in the medial quadrants. After implantation of the prosthesis the central and superior quadrants were predominantly contacted irrespective of the flexion angle. No marked differences between the flexion angles were found. Implantation of the patellar resurfacing led to contact in the three central quadrants.nnnCONCLUSIONnImplantation of the endoprosthesis leads to increased contact in slight and extreme flexion angles. Especially the central areas are increasingly loaded. No predominant influence of the rotation of the femoral component or the direction of the muscle pull was found. An improved distribution of the contact area could not be demonstrated after patellar resurfacing.

Primary stability of tibial components in TKA: in vitro comparison of two cementing techniques

In spite of improvements in cementing technique, migration of tibial component remains a problem in total knee arthroplasty. This study compares the primary stability of tibial components using two different cementing techniques with roentgen stereophotogrammetric analysis (RSA) in vitro. A total of 20 tibia specimens were matched into two groups, 10 specimens per group. Cementing technique was randomized to each group. In the first group only the base and in the second group the base and stem were cemented. The implants and the tibial metaphysis were marked with markers for the RSA analysis. All specimens were tested with an axial load of 2,000xa0N for 1,000 and 10,000 cycles and RSA analysis was performed. Endpoints for radiosterometric analysis were maximum total point motion, maximum subsidence, lift off, rotation and translation along the x-, y-, and z-axes. After 1,000 and 10,000 cycles, no significant differences could be found, but two tibial components of the surface cementing group showed a migration of more than 2xa0mm defined as failure compared to six failed tibial components in the full cementing group (Pxa0=xa00.068). This higher number of failed arthroplasties in the fully cemented prosthesis group demonstrates a disadvantageous load distribution in the tibia apophysis which can cause an early component loosening.

Quality of life and clinical outcome in salvage revision total knee replacement: hinged vs. total condylar design

This study compared the overall outcome after salvage revision total knee arthroplasty using hinged and nonhinged designs. We followed 26 total knee arthroplasties for an average of 20.4xa0months. The average age was 68.5xa0years. All patients had a salvage situation secondary to excessive bone loss, enlarged flexion gap, collateral ligament insufficiency, or extensor mechanism insufficiency. Ten patients received a hinged implant after an average of 2.8 prior total knee replacements. Sixteen patients received nonhinged constrained implants after an average of 3.4 prior total knee replacements. The outcome was evaluated using the Hospital for Special Surgery Score (HSS), the Knee Society Score (KSS), the Visual Analogue Scale for pain (VAS), the Tegner Activity Score, the Patella Score, and the Short Form-36 Health Survey (SF-36). There was a statistically significant difference in flexion range of motion between hinged and nonhinged designs (96.5° vs. 107.5°) but not in HSS, KSS, VAS, Tegner Activity Score, or Patella Score. Patients with hinged and nonhinged prostheses had significantly lower scores than an age-matched normal population in physical functioning, role limitations, and bodily pain on the SF-36 survey. However, patients with a hinged implant had no statistically significant difference compared to controls in the mental component summary. In salvage total knee arthroplasty the implant design does not significantly affect the overall functional outcome. However, patients with a hinged implant had significant better scores in the mental components of the SF36 quality-of-life assessment.

Damages of the tibial post in constrained total knee prostheses in the early postoperative course – a scanning electron microscopic study of polyethylene inlays

BackgroundInvestigation of the risk of fracture of the polyethylene (PE) inlay in constrained total knee prostheses.MethodsThree unused and seven polyethylene inlays that had been implanted in a patients knee for an average of 25.4 months (min 1.1 months, max 50.2 months) were investigated using scanning electron microscopy (SEM). All inlays were of the same type and size (Genesis II constrained, Smith & Nephew). The PE surface at the transition from the plateau to the post was analyzed.ResultsThe unused inlays had fissure-free surfaces. All inlays that had been implanted in a patients knee already had distinct fissures at the front and backside of the post.ConclusionThe fissures of the transition from the plateau to the post indicated a loading-induced irreversible mechanical deformation and possibly cause the fracture of the inlay.

Der Einfluss der Patellakinematik auf die tibiale Rotation nach Knie-Totalendoprothesen-Implantation / Influence of patellar position on tibial rotation after total knee arthroplasty

Zusammenfassung Ziel: Die Implantation von Knietotalendoprothesen erfordert in der Mehrzahl die Resektion des vorderen Kreuzbandes. Aufgrund entstehender ligamentärer Insuffizienz ist die tibiale Rotation verstärkt von anderen Faktoren abhängig. Die vorliegende Studie diente zur dynamischen in vitro-Messung des Einflusses der durch die mediolaterale Patellaposition bestimmten Zugrichtung des Kniestreckapparates auf die tibiale Rotation nach Implantation von zwei unterschiedlichen Knieendoprothesen. Material und Methode: Patella- und Tibiakinematik wurden zunächst anhand von 10 physiologischen, „fresh-frozen” humanen Kniegelenkspräparaten in einem Kniegelenkskinemator, der einen isokinetischen Extensionsversuch simuliert, ermittelt. Anschließend erfolgte die Messung nach Implantation der Interax®- bzw. Genesis II®-Knieendoprothese in je fünf Präparaten und eine Bewertung von signifikanten Unterschieden der Kniegelenkskinematik. Ergebnisse: Die maximale mediale Position der physiologischen Patella betrug -6,6 mm (entspricht Lateralisierung) relativ zum Tibiazentrum, die maximale tibiale Außenrotation 4,1°. Nach Implantation der Genesis II®-Knieendoprothese verringerte sich die tibiale Außenrotation signifikant (p=0,03) bei relativer Medialisierung der Patella (p=0,01), wohingegen sich nach Implantation der Interax®-Knieendoprothese eine signifikant (p=0,01) erhöhte tibiale Außenrotation bei einer physiologisch entsprechenden Lateralisierung der Patella zeigte. Schlussfolgerung: Die Ergebnisse der Studie lassen einen wesentlichen Einfluss der mediolateralen Patellaposition auf die tibiale Rotation nach Implantation einer Knieendoprothese vermuten, wobei keines der getesteten Prothesensysteme in der Lage ist, eine physiologische Gelenkkinematik vollständig zu reproduzieren.