P. Lechler

[Ankle arthroplasty: indications and current state].

Antecedent trauma is a major risk factor for the development of osteoarthritis of the ankle. Chronic inflammatory diseases, osteonecrosis and idiopathic arthritis are further important causes for ankle joint degeneration. Joint fusion represents the classic operative treatment of symptomatic ankle arthritis. The first attempts in total ankle replacement in the early 1970s led to high complication and revision rates. It was not until modern prosthesis designs respected the complex biomechanical conditions of the ankle joint that an alternative to joint fusion was available. Today a variety of models with specific advantages and disadvantages are available. Critical factors in ankle arthroplasty are proper patient selection and meticulous implantation.

Repair of local cartilage defects in the patellofemoral joint

Cartilage defects of the patellofemoral joint represent different entities. Results of patellofemoral cartilage repair are often variable. Concomitant pathologies, such as malalignment and instability are frequent. Currently no common treatment concept exists. Improvement of patellofemoral biomechanics, e.g. tubercle transfer, results in better outcome independent of the cartilage repair technique used. In patellofemoral instability reconstruction of the medial patellofemoral ligament (MPFL) has recently become a focus of interest. Microfracturing and osteochondral cylinder transfer/mosaicplasty are recommended for smaller defects, while comparative studies have shown advantages for autologous chondrocyte implantation (ACI) in defects larger than 4 cm². In our study patients with patellofemoral scaffold ACI (MACI®), better Lysholm scores were seen with isolated trochlea defects rather than patella defects or bipolar lesions. While trochlea defects can be effectively addressed, treatment of bipolar patellofemoral defects by scaffold ACI cannot generally be recommended. Follow-up treatment of the patellofemoral joint is more time and cost-consuming than other defect localizations. For the development of therapeutic algorithms further well-defined large randomized studies are necessary.ZusammenfassungPatellofemorale Knorpelschäden stellen keine ätiologische Entität dar. Komorbiditäten wie Malalignement oder Instabilität sind häufig. Die Ergebnisse patellofemoraler Knorpeloperationen sind variabel. Die aktuelle Studienlage lässt kein einheitliches Therapiekonzept erkennen: Tendenziell bessere Ergebnisse können verfahrensübergreifend durch eine Verbesserung der Biomechanik wie z.xa0B. dem Tuberositastransfer erzielt werden. Bei patellofemoraler Instabilität tritt die Rekonstruktion des medialen patellofemoralen Ligaments (MPFL) verstärkt in den Interessenfokus. Mikrofrakturierung oder osteochondraler Zylindertransfer bzw. Mosaikplastik werden eher für kleinere Defekte empfohlen. Für Defektgrößen ab 4xa0cm2 zeigen komparative Studien Vorteile für die autologe Chondrozytentransplantation (ACT). Bei unseren eigenen Patienten schnitten nach einer Matrix-ACT (MACI®) die isolierten Trochleadefekte vor den Patelladefekten und den bipolaren Läsionen im Lysholm-Score am besten ab. Während Trochleadefekte effektiv therapierbar sind, kann eine ACT bei bipolaren Läsionen nicht uneingeschränkt empfohlen werden. Die Nachbehandlung patellofemoraler Läsionen geht mit einem erhöhten Bedarf an Zeit und Ressourcen einher. Weitere klar definierte komparative randomisierte Studien mit größeren Fallzahlen sind für die Entwicklung eines differenziellen Therapiealgorithmus notwendig.AbstractCartilage defects of the patellofemoral joint represent different entities. Results of patellofemoral cartilage repair are often variable. Concomitant pathologies, such as malalignment and instability are frequent. Currently no common treatment concept exists. Improvement of patellofemoral biomechanics, e.g. tubercle transfer, results in better outcome independent of the cartilage repair technique used. In patellofemoral instability reconstruction of the medial patellofemoral ligament (MPFL) has recently become a focus of interest. Microfracturing and osteochondral cylinder transfer/mosaicplasty are recommended for smaller defects, while comparative studies have shown advantages for autologous chondrocyte implantation (ACI) in defects larger than 4xa0cm2. In our study patients with patellofemoral scaffold ACI (MACI®), better Lysholm scores were seen with isolated trochlea defects rather than patella defects or bipolar lesions. While trochlea defects can be effectively addressed, treatment of bipolar patellofemoral defects by scaffold ACI cannot generally be recommended. Follow-up treatment of the patellofemoral joint is more time and cost-consuming than other defect localizations. For the development of therapeutic algorithms further well-defined large randomized studies are necessary.

Therapie lokaler Knorpelschäden im Patellofemoralgelenk

Cartilage defects of the patellofemoral joint represent different entities. Results of patellofemoral cartilage repair are often variable. Concomitant pathologies, such as malalignment and instability are frequent. Currently no common treatment concept exists. Improvement of patellofemoral biomechanics, e.g. tubercle transfer, results in better outcome independent of the cartilage repair technique used. In patellofemoral instability reconstruction of the medial patellofemoral ligament (MPFL) has recently become a focus of interest. Microfracturing and osteochondral cylinder transfer/mosaicplasty are recommended for smaller defects, while comparative studies have shown advantages for autologous chondrocyte implantation (ACI) in defects larger than 4 cm². In our study patients with patellofemoral scaffold ACI (MACI®), better Lysholm scores were seen with isolated trochlea defects rather than patella defects or bipolar lesions. While trochlea defects can be effectively addressed, treatment of bipolar patellofemoral defects by scaffold ACI cannot generally be recommended. Follow-up treatment of the patellofemoral joint is more time and cost-consuming than other defect localizations. For the development of therapeutic algorithms further well-defined large randomized studies are necessary.ZusammenfassungPatellofemorale Knorpelschäden stellen keine ätiologische Entität dar. Komorbiditäten wie Malalignement oder Instabilität sind häufig. Die Ergebnisse patellofemoraler Knorpeloperationen sind variabel. Die aktuelle Studienlage lässt kein einheitliches Therapiekonzept erkennen: Tendenziell bessere Ergebnisse können verfahrensübergreifend durch eine Verbesserung der Biomechanik wie z.xa0B. dem Tuberositastransfer erzielt werden. Bei patellofemoraler Instabilität tritt die Rekonstruktion des medialen patellofemoralen Ligaments (MPFL) verstärkt in den Interessenfokus. Mikrofrakturierung oder osteochondraler Zylindertransfer bzw. Mosaikplastik werden eher für kleinere Defekte empfohlen. Für Defektgrößen ab 4xa0cm2 zeigen komparative Studien Vorteile für die autologe Chondrozytentransplantation (ACT). Bei unseren eigenen Patienten schnitten nach einer Matrix-ACT (MACI®) die isolierten Trochleadefekte vor den Patelladefekten und den bipolaren Läsionen im Lysholm-Score am besten ab. Während Trochleadefekte effektiv therapierbar sind, kann eine ACT bei bipolaren Läsionen nicht uneingeschränkt empfohlen werden. Die Nachbehandlung patellofemoraler Läsionen geht mit einem erhöhten Bedarf an Zeit und Ressourcen einher. Weitere klar definierte komparative randomisierte Studien mit größeren Fallzahlen sind für die Entwicklung eines differenziellen Therapiealgorithmus notwendig.AbstractCartilage defects of the patellofemoral joint represent different entities. Results of patellofemoral cartilage repair are often variable. Concomitant pathologies, such as malalignment and instability are frequent. Currently no common treatment concept exists. Improvement of patellofemoral biomechanics, e.g. tubercle transfer, results in better outcome independent of the cartilage repair technique used. In patellofemoral instability reconstruction of the medial patellofemoral ligament (MPFL) has recently become a focus of interest. Microfracturing and osteochondral cylinder transfer/mosaicplasty are recommended for smaller defects, while comparative studies have shown advantages for autologous chondrocyte implantation (ACI) in defects larger than 4xa0cm2. In our study patients with patellofemoral scaffold ACI (MACI®), better Lysholm scores were seen with isolated trochlea defects rather than patella defects or bipolar lesions. While trochlea defects can be effectively addressed, treatment of bipolar patellofemoral defects by scaffold ACI cannot generally be recommended. Follow-up treatment of the patellofemoral joint is more time and cost-consuming than other defect localizations. For the development of therapeutic algorithms further well-defined large randomized studies are necessary.

[Denervation of the patella: influence on mid-term results after total knee arthroplasty].

BACKGROUNDnThe purpose of the study was to determine possible differences in the mid-term results of total knee arthroplasty in patients treated with and without denervation of the patella.nnnPATIENTS AND METHODSnThis study included 80 total knee replacements in 71 patients who were treated with total knee replacement, either with (nu2009=u200940) or without (nu2009=u200940) simultaneous denervation of the patella out of a total population with 122 knee replacements in 100 patients. Comparability of both groups was achieved by applying matching criteria. All patients were reviewed by isokinetic tests, physical and radiological examination. The mean follow-up time was 2.2 years.nnnRESULTSnThe mean hospital for special surgery (HSS) score revealed no statistically significant differences between both groups (with denervation 77.9u2009±u200911.1 and without denervation 77.8u2009±u200911.0, pu2009=u20090.976). The isokinetic torque measurements with low angle velocity (60°/s) indicated slightly higher values during extension (60.2u2009±u200932.2xa0Nm versus 55.8u2009±u200925.2xa0Nm, pu2009=u20090.497) and flexion (52.4u2009±u200928.3xa0Nm versus 46.1u2009±u200922.3xa0Nm, pu2009=u20090.272) movements of the affected knee joint. However, the differences did not reach statistical significance. At high angle velocity (180°/s) no differences could be found between both groups. No cases of postoperative necrosis of the patella were observed. Anterior knee pain after denervation was reported in 6 cases (15u2009%) compared to 10 cases (25u2009%) in patients who were treated without denervation (pu2009=u20090.402).nnnCONCLUSIONnNo statistically significant differences could be found between patients with and without denervation of the patella for total knee arthroplasty.ZusammenfassungHintergrundZiel unserer Untersuchung war es, den Einfluss einer retropatellaren Denervierung auf die mittelfristigen Ergebnisse nach Implantation von Knietotalendoprothesen (KTEP) zu untersuchen.Patienten und MethodenEs wurden 122 Kniegelenkendoprothesen ohne Retropatellarersatz von 100xa0Patienten nachuntersucht, bei denen in 58 Fällen im Rahmen der Implantation eine retropatellare Denervierung durchgeführt worden war, und 64 Fälle, bei denen auf diese Prozedur verzichtet wurde. Durch ein Matchingverfahren wurden 2 vergleichbare Gruppen mit jeweils 40 KTEP bei insgesamt 71xa0Patienten gebildet, welche entweder mit oder ohne retropatellare Denervierung operiert worden waren. Diese Gruppen wurden nach durchschnittlich 2,2xa0Jahren klinisch, radiologisch und mit einem isokinetischen Dynamometer nachuntersucht.ErgebnisseBeide Gruppen zeigten vergleichbare Werte beim Hospital-for-special-surgery(HSS)-Score (mit Denervierung 77,9u2009±u200911,1; ohne Denervierung 77,8u2009±u200911,0; pu2009=u20090,976). Bei niedriger Winkelgeschwindigkeit (60°/s) erzeugten die Patienten mit Denervierung durchschnittlich sowohl bei Extension (60,2u2009±u200932,2 vs. 55,8u2009±u200925,2xa0Nm; pu2009=u20090,497) als auch bei Flexion im Kniegelenk (52,4u2009±u200928,3 vs. 46,1u2009±u200922,3xa0Nm; pu2009=u20090,272) leicht höhere Drehmomentwerte als die Patienten ohne Denervierung. Die gemessenen Unterschiede waren jedoch statistisch nicht signifikant. Bei hoher Winkelgeschwindigkeit (180°/s) waren die gemessenen Drehmomentwerte in beiden Gruppen nahezu identisch. Eine Patellanekrose wurde bei keinem der Patienten beobachtet. Patienten mit Denervierung klagten mit 6 (15u2009%) gegenüber 10 Fällen (25u2009%) etwas seltener über retropatellare Schmerzen. Die unterschiedliche Häufigkeit war jedoch ebenfalls statistisch nicht signifikant (pu2009=u20090,402).SchlussfolgerungEs zeigten sich mittelfristig nach Knieprothesenimplantation keine signifikanten Unterschiede bei Patienten mit und ohne retropatellare Denervierung.AbstractBackgroundThe purpose of the study was to determine possible differences in the mid-term results of total knee arthroplasty in patients treated with and without denervation of the patella.Patients and methodsThis study included 80 total knee replacements in 71 patients who were treated with total knee replacement, either with (nu2009=u200940) or without (nu2009=u200940) simultaneous denervation of the patella out of a total population with 122 knee replacements in 100 patients. Comparability of both groups was achieved by applying matching criteria. All patients were reviewed by isokinetic tests, physical and radiological examination. The mean follow-up time was 2.2 years.ResultsThe mean hospital for special surgery (HSS) score revealed no statistically significant differences between both groups (with denervation 77.9u2009±u200911.1 and without denervation 77.8u2009±u200911.0, pu2009=u20090.976). The isokinetic torque measurements with low angle velocity (60°/s) indicated slightly higher values during extension (60.2u2009±u200932.2xa0Nm versus 55.8u2009±u200925.2xa0Nm, pu2009=u20090.497) and flexion (52.4u2009±u200928.3xa0Nm versus 46.1u2009±u200922.3xa0Nm, pu2009=u20090.272) movements of the affected knee joint. However, the differences did not reach statistical significance. At high angle velocity (180°/s) no differences could be found between both groups. No cases of postoperative necrosis of the patella were observed. Anterior knee pain after denervation was reported in 6 cases (15u2009%) compared to 10 cases (25u2009%) in patients who were treated without denervation (pu2009=u20090.402).ConclusionNo statistically significant differences could be found between patients with and without denervation of the patella for total knee arthroplasty.

[The 2-year follow-up results of a patient-specific interpositional knee implant].

ZusammenfassungHintergrundIn der operativen Therapie der unikompartimentellen Gonarthrose des jüngeren Patienten steht neben den primären Zielen einer Funktionsverbesserung und Schmerzreduktion der Erhalt intakter Knochen- und Gelenkstrukturen im Fokus. Es stellt sich die Frage, ob ein auf Basis von MRT-Daten gefertigtes interpositionelles Knieimplantat neben den bewährten Verfahren der gelenknahen Korrekturosteotomie und dem unikompartimentellen Gelenkersatz eine mögliche Therapiealternative darstellt.Patienten und MethodenIn einer prospektiven Single-arm-Studie wurden 33xa0Patienten mit unikompartimenteller Gonarthrose von Juni 2004 bis Mai 2008 mit einem patientenspezifischen Interpositionsimplantat versorgt (31 mediale, 2 laterale Implantate). Der mittlere Nachbeobachtungszeitraum betrug 26,6 (1–48xa0Monate), das mittlere Patientenalter 54,5 (39–65xa0Jahre). Neben den klinischen Befunden wurden die WOMAC Function Scale und die Knee Society Scores erfasst. Es erfolgten eine deskriptive Datenanalyse, eine Varianzanalyse für wiederholte Messungen und eine Bestimmung des Signifikanzniveaus.ErgebnisseDie Zwei-Jahres-Resultate brachten eine signifikante Verbesserung in der WOMAC Function Scale und den Knee Society Scores sowie eine nach 2xa0Jahren im Vergleich zur präoperativen Situation unverändert gute Beweglichkeit von Extension/Flexion von 0/2/130°. Die Rate an Implantatdislokationen lag bei 6%, die Gesamtrevisionsrate bei 21%.SchlussfolgerungTrotz akzeptabler funktioneller Resultate, einer signifikanten Schmerzreduktion, einem vollen Erhalt der Knochensubstanz und einer im Vergleich zum konfektionierten Unispacer geringeren Implantatdislokationsrate besteht aufgrund der hohen Revisionsraten nach 2xa0Jahren für den Einsatz eines individualisierten Knieinterpositionsimplantats nur eine limitierte Indikation unter Beachtung der Kontraindikationen.AbstractBackgroundBesides the primary goal of functional improvement and pain reduction, the operative treatment of unicompartmental arthritis in younger patients is focused on preservation of intact bone and joint structures. The question arises whether an interpositional knee implant based on magnetic resonance imaging (MRI) data can be an alternative treatment option to the established procedures of high tibial osteotomy and unicompartmental knee arthroplasty.MethodsFrom June 2004 to May 2008 a total of 33 patients suffering from unicompartmental knee arthritis received a patient-specific interpositional implant (31 medial and 2 lateral) within a single arm trial. The mean follow-up time was 26.6xa0months (range 1–48xa0months) and the mean age of the patients was 54.5xa0years (range 39–65xa0years). In addition to the clinical results the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) function scale and the Knee Society scores were measured. A descriptive data analysis, a variance analysis for repeated measurements and a determination of significance level were carried out.ResultsThe 2–4xa0year results showed a significant improvement in the WOMAC function scale as well as the Knee Society scores. The knee function after 2 years was comparable to the preoperative situation with an extension to flexion of 0/2/130°. The dislocation rate was 6% and the overall revision rate 21%.ConclusionDespite acceptable functional results a significant pain relief, a complete preservation of bone and a lower rate of dislocations compared to the off-the-shelf Unispacer implant there were only limited indications for the customized interpositional knee implant with respect to the given contraindications due to the high 2xa0year revision rate.BACKGROUNDnBesides the primary goal of functional improvement and pain reduction, the operative treatment of unicompartmental arthritis in younger patients is focused on preservation of intact bone and joint structures. The question arises whether an interpositional knee implant based on magnetic resonance imaging (MRI) data can be an alternative treatment option to the established procedures of high tibial osteotomy and unicompartmental knee arthroplasty.nnnMETHODSnFrom June 2004 to May 2008 a total of 33 patients suffering from unicompartmental knee arthritis received a patient-specific interpositional implant (31 medial and 2 lateral) within a single arm trial. The mean follow-up time was 26.6 months (range 1-48 months) and the mean age of the patients was 54.5 years (range 39-65 years). In addition to the clinical results the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) function scale and the Knee Society scores were measured. A descriptive data analysis, a variance analysis for repeated measurements and a determination of significance level were carried out.nnnRESULTSnThe 2-4 year results showed a significant improvement in the WOMAC function scale as well as the Knee Society scores. The knee function after 2 years was comparable to the preoperative situation with an extension to flexion of 0/2/130°. The dislocation rate was 6% and the overall revision rate 21%.nnnCONCLUSIONnDespite acceptable functional results a significant pain relief, a complete preservation of bone and a lower rate of dislocations compared to the off-the-shelf Unispacer implant there were only limited indications for the customized interpositional knee implant with respect to the given contraindications due to the high 2 year revision rate.

Zwei-Jahres-Resultate mit einem patientenspezifischen metallischen Knieinterpositionsimplantat

ZusammenfassungHintergrundIn der operativen Therapie der unikompartimentellen Gonarthrose des jüngeren Patienten steht neben den primären Zielen einer Funktionsverbesserung und Schmerzreduktion der Erhalt intakter Knochen- und Gelenkstrukturen im Fokus. Es stellt sich die Frage, ob ein auf Basis von MRT-Daten gefertigtes interpositionelles Knieimplantat neben den bewährten Verfahren der gelenknahen Korrekturosteotomie und dem unikompartimentellen Gelenkersatz eine mögliche Therapiealternative darstellt.Patienten und MethodenIn einer prospektiven Single-arm-Studie wurden 33xa0Patienten mit unikompartimenteller Gonarthrose von Juni 2004 bis Mai 2008 mit einem patientenspezifischen Interpositionsimplantat versorgt (31 mediale, 2 laterale Implantate). Der mittlere Nachbeobachtungszeitraum betrug 26,6 (1–48xa0Monate), das mittlere Patientenalter 54,5 (39–65xa0Jahre). Neben den klinischen Befunden wurden die WOMAC Function Scale und die Knee Society Scores erfasst. Es erfolgten eine deskriptive Datenanalyse, eine Varianzanalyse für wiederholte Messungen und eine Bestimmung des Signifikanzniveaus.ErgebnisseDie Zwei-Jahres-Resultate brachten eine signifikante Verbesserung in der WOMAC Function Scale und den Knee Society Scores sowie eine nach 2xa0Jahren im Vergleich zur präoperativen Situation unverändert gute Beweglichkeit von Extension/Flexion von 0/2/130°. Die Rate an Implantatdislokationen lag bei 6%, die Gesamtrevisionsrate bei 21%.SchlussfolgerungTrotz akzeptabler funktioneller Resultate, einer signifikanten Schmerzreduktion, einem vollen Erhalt der Knochensubstanz und einer im Vergleich zum konfektionierten Unispacer geringeren Implantatdislokationsrate besteht aufgrund der hohen Revisionsraten nach 2xa0Jahren für den Einsatz eines individualisierten Knieinterpositionsimplantats nur eine limitierte Indikation unter Beachtung der Kontraindikationen.AbstractBackgroundBesides the primary goal of functional improvement and pain reduction, the operative treatment of unicompartmental arthritis in younger patients is focused on preservation of intact bone and joint structures. The question arises whether an interpositional knee implant based on magnetic resonance imaging (MRI) data can be an alternative treatment option to the established procedures of high tibial osteotomy and unicompartmental knee arthroplasty.MethodsFrom June 2004 to May 2008 a total of 33 patients suffering from unicompartmental knee arthritis received a patient-specific interpositional implant (31 medial and 2 lateral) within a single arm trial. The mean follow-up time was 26.6xa0months (range 1–48xa0months) and the mean age of the patients was 54.5xa0years (range 39–65xa0years). In addition to the clinical results the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) function scale and the Knee Society scores were measured. A descriptive data analysis, a variance analysis for repeated measurements and a determination of significance level were carried out.ResultsThe 2–4xa0year results showed a significant improvement in the WOMAC function scale as well as the Knee Society scores. The knee function after 2 years was comparable to the preoperative situation with an extension to flexion of 0/2/130°. The dislocation rate was 6% and the overall revision rate 21%.ConclusionDespite acceptable functional results a significant pain relief, a complete preservation of bone and a lower rate of dislocations compared to the off-the-shelf Unispacer implant there were only limited indications for the customized interpositional knee implant with respect to the given contraindications due to the high 2xa0year revision rate.BACKGROUNDnBesides the primary goal of functional improvement and pain reduction, the operative treatment of unicompartmental arthritis in younger patients is focused on preservation of intact bone and joint structures. The question arises whether an interpositional knee implant based on magnetic resonance imaging (MRI) data can be an alternative treatment option to the established procedures of high tibial osteotomy and unicompartmental knee arthroplasty.nnnMETHODSnFrom June 2004 to May 2008 a total of 33 patients suffering from unicompartmental knee arthritis received a patient-specific interpositional implant (31 medial and 2 lateral) within a single arm trial. The mean follow-up time was 26.6 months (range 1-48 months) and the mean age of the patients was 54.5 years (range 39-65 years). In addition to the clinical results the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) function scale and the Knee Society scores were measured. A descriptive data analysis, a variance analysis for repeated measurements and a determination of significance level were carried out.nnnRESULTSnThe 2-4 year results showed a significant improvement in the WOMAC function scale as well as the Knee Society scores. The knee function after 2 years was comparable to the preoperative situation with an extension to flexion of 0/2/130°. The dislocation rate was 6% and the overall revision rate 21%.nnnCONCLUSIONnDespite acceptable functional results a significant pain relief, a complete preservation of bone and a lower rate of dislocations compared to the off-the-shelf Unispacer implant there were only limited indications for the customized interpositional knee implant with respect to the given contraindications due to the high 2 year revision rate.

Therapie lokaler Knorpelschäden im Patellofemoralgelenk@@@Repair of local cartilage defects in the patellofemoral joint

Cartilage defects of the patellofemoral joint represent different entities. Results of patellofemoral cartilage repair are often variable. Concomitant pathologies, such as malalignment and instability are frequent. Currently no common treatment concept exists. Improvement of patellofemoral biomechanics, e.g. tubercle transfer, results in better outcome independent of the cartilage repair technique used. In patellofemoral instability reconstruction of the medial patellofemoral ligament (MPFL) has recently become a focus of interest. Microfracturing and osteochondral cylinder transfer/mosaicplasty are recommended for smaller defects, while comparative studies have shown advantages for autologous chondrocyte implantation (ACI) in defects larger than 4 cm². In our study patients with patellofemoral scaffold ACI (MACI®), better Lysholm scores were seen with isolated trochlea defects rather than patella defects or bipolar lesions. While trochlea defects can be effectively addressed, treatment of bipolar patellofemoral defects by scaffold ACI cannot generally be recommended. Follow-up treatment of the patellofemoral joint is more time and cost-consuming than other defect localizations. For the development of therapeutic algorithms further well-defined large randomized studies are necessary.ZusammenfassungPatellofemorale Knorpelschäden stellen keine ätiologische Entität dar. Komorbiditäten wie Malalignement oder Instabilität sind häufig. Die Ergebnisse patellofemoraler Knorpeloperationen sind variabel. Die aktuelle Studienlage lässt kein einheitliches Therapiekonzept erkennen: Tendenziell bessere Ergebnisse können verfahrensübergreifend durch eine Verbesserung der Biomechanik wie z.xa0B. dem Tuberositastransfer erzielt werden. Bei patellofemoraler Instabilität tritt die Rekonstruktion des medialen patellofemoralen Ligaments (MPFL) verstärkt in den Interessenfokus. Mikrofrakturierung oder osteochondraler Zylindertransfer bzw. Mosaikplastik werden eher für kleinere Defekte empfohlen. Für Defektgrößen ab 4xa0cm2 zeigen komparative Studien Vorteile für die autologe Chondrozytentransplantation (ACT). Bei unseren eigenen Patienten schnitten nach einer Matrix-ACT (MACI®) die isolierten Trochleadefekte vor den Patelladefekten und den bipolaren Läsionen im Lysholm-Score am besten ab. Während Trochleadefekte effektiv therapierbar sind, kann eine ACT bei bipolaren Läsionen nicht uneingeschränkt empfohlen werden. Die Nachbehandlung patellofemoraler Läsionen geht mit einem erhöhten Bedarf an Zeit und Ressourcen einher. Weitere klar definierte komparative randomisierte Studien mit größeren Fallzahlen sind für die Entwicklung eines differenziellen Therapiealgorithmus notwendig.AbstractCartilage defects of the patellofemoral joint represent different entities. Results of patellofemoral cartilage repair are often variable. Concomitant pathologies, such as malalignment and instability are frequent. Currently no common treatment concept exists. Improvement of patellofemoral biomechanics, e.g. tubercle transfer, results in better outcome independent of the cartilage repair technique used. In patellofemoral instability reconstruction of the medial patellofemoral ligament (MPFL) has recently become a focus of interest. Microfracturing and osteochondral cylinder transfer/mosaicplasty are recommended for smaller defects, while comparative studies have shown advantages for autologous chondrocyte implantation (ACI) in defects larger than 4xa0cm2. In our study patients with patellofemoral scaffold ACI (MACI®), better Lysholm scores were seen with isolated trochlea defects rather than patella defects or bipolar lesions. While trochlea defects can be effectively addressed, treatment of bipolar patellofemoral defects by scaffold ACI cannot generally be recommended. Follow-up treatment of the patellofemoral joint is more time and cost-consuming than other defect localizations. For the development of therapeutic algorithms further well-defined large randomized studies are necessary.

Das „onkofetale“ Gen Survivin – ein mögliches Ziel-Gen regenerativer Therapiekonzepte im Gelenkknorpel

Survivin, the smallest member of the inhibitor of the apoptosis protein gene family (IAP) is a key molecule for mammalian cell cycle regulation and cellular survival. Of note these functions have been thought to be limited to embryonic and malignant tissues. However, a growing body of evidence indicates a limited expression of survivin in some highly specific adult tissues and cells. In the present study it has been demonstrated that the antiapoptotic protein survivin is re-expressed in osteoarthritic human cartilage and primary human chondrocytes. Furthermore, the data indicated that survivin significantly affects cell cycle regulation and cellular survival. The modulation of survivin expression and function in cartilaginous tissues might be important for understanding osteoarthritis and the development of regenerative strategies.ZusammenfassungSurvivin ist das kleinste Mitglied der Inhibitor-of-apoptosis-protein(IAP)-Gen-Familie und erfüllt entscheidende Aufgaben in der Regulation des Zellzyklusses und des zellulären Überlebens. Diese Funktionen wurden bisher lediglich in Tumoren, der Embryonalentwicklung und in einzelnen hochdifferenzierten Geweben beobachtet.Im Rahmen dieser Studie wird über die Expression des onkofetalen Gens Survivin in primären humanen chondrozytären Kulturen und dessen Reexpression im osteoarthrotisch veränderten Gelenkknorpel berichtet. Des Weiteren konnte ein ausgeprägter Einfluss des Gens auf Zellzyklus und Zellüberlebensentscheidungen in primären humanen Chondrozyten nachgewiesen werden. Diese Funktionen sind für die Aufrechterhaltung der kartilaginären Integrität essenziell und limitieren die In-vitro-Kultivierung von autologem Knorpelersatz. Die Modulation der Survivinexpression und Funktion in Chondrozyten könnte zukünftig eine Rolle im Rahmen regenerativer Knorpeltherapieverfahren einnehmen.AbstractSurvivin, the smallest member of the inhibitor of the apoptosis protein gene family (IAP) is a key molecule for mammalian cell cycle regulation and cellular survival. Of note these functions have been thought to be limited to embryonic and malignant tissues. However, a growing body of evidence indicates a limited expression of survivin in some highly specific adult tissues and cells. In the present study it has been demonstrated that the antiapoptotic protein survivin is re-expressed in osteoarthritic human cartilage and primary human chondrocytes. Furthermore, the data indicated that survivin significantly affects cell cycle regulation and cellular survival. The modulation of survivin expression and function in cartilaginous tissues might be important for understanding osteoarthritis and the development of regenerative strategies.

Das „onkofetale“ Gen Survivin – ein mögliches Ziel-Gen regenerativer Therapiekonzepte im Gelenkknorpel@@@The oncofetal gene survivin – a possible target gene for regenerative therapy concepts in cartilaginous tissue

Survivin, the smallest member of the inhibitor of the apoptosis protein gene family (IAP) is a key molecule for mammalian cell cycle regulation and cellular survival. Of note these functions have been thought to be limited to embryonic and malignant tissues. However, a growing body of evidence indicates a limited expression of survivin in some highly specific adult tissues and cells. In the present study it has been demonstrated that the antiapoptotic protein survivin is re-expressed in osteoarthritic human cartilage and primary human chondrocytes. Furthermore, the data indicated that survivin significantly affects cell cycle regulation and cellular survival. The modulation of survivin expression and function in cartilaginous tissues might be important for understanding osteoarthritis and the development of regenerative strategies.ZusammenfassungSurvivin ist das kleinste Mitglied der Inhibitor-of-apoptosis-protein(IAP)-Gen-Familie und erfüllt entscheidende Aufgaben in der Regulation des Zellzyklusses und des zellulären Überlebens. Diese Funktionen wurden bisher lediglich in Tumoren, der Embryonalentwicklung und in einzelnen hochdifferenzierten Geweben beobachtet.Im Rahmen dieser Studie wird über die Expression des onkofetalen Gens Survivin in primären humanen chondrozytären Kulturen und dessen Reexpression im osteoarthrotisch veränderten Gelenkknorpel berichtet. Des Weiteren konnte ein ausgeprägter Einfluss des Gens auf Zellzyklus und Zellüberlebensentscheidungen in primären humanen Chondrozyten nachgewiesen werden. Diese Funktionen sind für die Aufrechterhaltung der kartilaginären Integrität essenziell und limitieren die In-vitro-Kultivierung von autologem Knorpelersatz. Die Modulation der Survivinexpression und Funktion in Chondrozyten könnte zukünftig eine Rolle im Rahmen regenerativer Knorpeltherapieverfahren einnehmen.AbstractSurvivin, the smallest member of the inhibitor of the apoptosis protein gene family (IAP) is a key molecule for mammalian cell cycle regulation and cellular survival. Of note these functions have been thought to be limited to embryonic and malignant tissues. However, a growing body of evidence indicates a limited expression of survivin in some highly specific adult tissues and cells. In the present study it has been demonstrated that the antiapoptotic protein survivin is re-expressed in osteoarthritic human cartilage and primary human chondrocytes. Furthermore, the data indicated that survivin significantly affects cell cycle regulation and cellular survival. The modulation of survivin expression and function in cartilaginous tissues might be important for understanding osteoarthritis and the development of regenerative strategies.

Zwei-Jahres-Resultate mit einem patientenspezifischen metallischen Knieinterpositionsimplantat@@@The 2-year follow-up results of a patient-specific interpositional knee implant

ZusammenfassungHintergrundIn der operativen Therapie der unikompartimentellen Gonarthrose des jüngeren Patienten steht neben den primären Zielen einer Funktionsverbesserung und Schmerzreduktion der Erhalt intakter Knochen- und Gelenkstrukturen im Fokus. Es stellt sich die Frage, ob ein auf Basis von MRT-Daten gefertigtes interpositionelles Knieimplantat neben den bewährten Verfahren der gelenknahen Korrekturosteotomie und dem unikompartimentellen Gelenkersatz eine mögliche Therapiealternative darstellt.Patienten und MethodenIn einer prospektiven Single-arm-Studie wurden 33xa0Patienten mit unikompartimenteller Gonarthrose von Juni 2004 bis Mai 2008 mit einem patientenspezifischen Interpositionsimplantat versorgt (31 mediale, 2 laterale Implantate). Der mittlere Nachbeobachtungszeitraum betrug 26,6 (1–48xa0Monate), das mittlere Patientenalter 54,5 (39–65xa0Jahre). Neben den klinischen Befunden wurden die WOMAC Function Scale und die Knee Society Scores erfasst. Es erfolgten eine deskriptive Datenanalyse, eine Varianzanalyse für wiederholte Messungen und eine Bestimmung des Signifikanzniveaus.ErgebnisseDie Zwei-Jahres-Resultate brachten eine signifikante Verbesserung in der WOMAC Function Scale und den Knee Society Scores sowie eine nach 2xa0Jahren im Vergleich zur präoperativen Situation unverändert gute Beweglichkeit von Extension/Flexion von 0/2/130°. Die Rate an Implantatdislokationen lag bei 6%, die Gesamtrevisionsrate bei 21%.SchlussfolgerungTrotz akzeptabler funktioneller Resultate, einer signifikanten Schmerzreduktion, einem vollen Erhalt der Knochensubstanz und einer im Vergleich zum konfektionierten Unispacer geringeren Implantatdislokationsrate besteht aufgrund der hohen Revisionsraten nach 2xa0Jahren für den Einsatz eines individualisierten Knieinterpositionsimplantats nur eine limitierte Indikation unter Beachtung der Kontraindikationen.AbstractBackgroundBesides the primary goal of functional improvement and pain reduction, the operative treatment of unicompartmental arthritis in younger patients is focused on preservation of intact bone and joint structures. The question arises whether an interpositional knee implant based on magnetic resonance imaging (MRI) data can be an alternative treatment option to the established procedures of high tibial osteotomy and unicompartmental knee arthroplasty.MethodsFrom June 2004 to May 2008 a total of 33 patients suffering from unicompartmental knee arthritis received a patient-specific interpositional implant (31 medial and 2 lateral) within a single arm trial. The mean follow-up time was 26.6xa0months (range 1–48xa0months) and the mean age of the patients was 54.5xa0years (range 39–65xa0years). In addition to the clinical results the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) function scale and the Knee Society scores were measured. A descriptive data analysis, a variance analysis for repeated measurements and a determination of significance level were carried out.ResultsThe 2–4xa0year results showed a significant improvement in the WOMAC function scale as well as the Knee Society scores. The knee function after 2 years was comparable to the preoperative situation with an extension to flexion of 0/2/130°. The dislocation rate was 6% and the overall revision rate 21%.ConclusionDespite acceptable functional results a significant pain relief, a complete preservation of bone and a lower rate of dislocations compared to the off-the-shelf Unispacer implant there were only limited indications for the customized interpositional knee implant with respect to the given contraindications due to the high 2xa0year revision rate.BACKGROUNDnBesides the primary goal of functional improvement and pain reduction, the operative treatment of unicompartmental arthritis in younger patients is focused on preservation of intact bone and joint structures. The question arises whether an interpositional knee implant based on magnetic resonance imaging (MRI) data can be an alternative treatment option to the established procedures of high tibial osteotomy and unicompartmental knee arthroplasty.nnnMETHODSnFrom June 2004 to May 2008 a total of 33 patients suffering from unicompartmental knee arthritis received a patient-specific interpositional implant (31 medial and 2 lateral) within a single arm trial. The mean follow-up time was 26.6 months (range 1-48 months) and the mean age of the patients was 54.5 years (range 39-65 years). In addition to the clinical results the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) function scale and the Knee Society scores were measured. A descriptive data analysis, a variance analysis for repeated measurements and a determination of significance level were carried out.nnnRESULTSnThe 2-4 year results showed a significant improvement in the WOMAC function scale as well as the Knee Society scores. The knee function after 2 years was comparable to the preoperative situation with an extension to flexion of 0/2/130°. The dislocation rate was 6% and the overall revision rate 21%.nnnCONCLUSIONnDespite acceptable functional results a significant pain relief, a complete preservation of bone and a lower rate of dislocations compared to the off-the-shelf Unispacer implant there were only limited indications for the customized interpositional knee implant with respect to the given contraindications due to the high 2 year revision rate.