Daniel Hensler

Anatomical double-bundle MPFL reconstruction with an aperture fixation

Since biomechanical studies have shown that the medial patellofemoral ligament (MPFL) is the main restraint against lateral patella displacement, reconstruction of the MPFL has become an accepted method of restoring patellofemoral stability and numerous techniques were described. Due to biomechanical examinations and clinical results, an anatomical double-bundle reconstruction of the “sail-like” MPFL is a reasonable method for achieving stability during complete extension and lower flexion degree. This method also serves to avoid rotation of the patella, providing immediate stability throughout the normal range of motion. However, until today, an aperture fixation technique at the patellar insertion with two bundles has not been described previously. This technique can provide an immediate stability to allow an early rehabilitation with full range of motion.

A Fibrin Glue Composition as Carrier for Nucleic Acid Vectors

PurposeGene delivery from biomaterials has become an important tool in tissue engineering. The purpose of this study was to generate a gene vector-doted fibrin glue as a versatile injectable implant to be used in gene therapy supported tissue regeneration.MethodsCopolymer-protected polyethylenimine(PEI)-DNA vectors (COPROGs), naked DNA and PEI-DNA were formulated with the fibrinogen component of the fibrin glue TISSUCOL® and lyophilized. Clotting parameters upon rehydration and thrombin addition were measured, vector release from fibrin clots was determined. Structural characterizations were carried out by electron microscopy. Reporter and growth factor gene delivery to primary keratinocytes and chondrocytes in vitro was examined. Finally,chondrocyte colonized clots were tested for their potency in cartilage regeneration in a osteochondral defect model.ResultsThe optimized glue is based on the fibrinogen component of TISSUCOL®, a fibrin glue widely used in the clinics, co-lyophilized with copolymer-protected polyethylenimine(PEI)- DNA vectors (COPROGs). This material, when rehydrated, forms vector-containing clots in situ upon thrombin addition and is suitable to mediate growth factor gene delivery to primary keratinocytes and primary chondrocytes admixed before clotting. Unprotected PEI-DNA in the same setup was comparatively unsuitable for clot formation while naked DNA was ineffective in transfection. Naked DNA was released rapidly from fibrin clots (>70% within the first seven days) in contrast to COPROGs which remained tightly immobilized over extended periods of time (0.29% release per day). Electron microscopy of chondrocytecolonized COPROG-clots revealed avid endocytotic vector uptake. In situ BMP-2 gene transfection and subsequent expression in chondrocytes grown in COPROG clots resulted in the upregulation of alkaline phosphatase expression and increased extracellular matrix formation in vitro. COPROG-fibrinogen preparations with admixed autologous chondrocytes when clotted in situ in osteochondral defects in the patellar grooves of rabbit femura gave rise to luciferase reporter gene expression detectable for two weeks (n=3 animals per group). However, no significant improvement in cartilage formation in osteochondral defects filled with autologous chondrocytes in BMP-2-COPROG clots was achieved in comparison to controls (n=8 animals per group).ConclusionsCOPROGs co-lyophilized with fibrinogen are a simple basis for an injectable fibrin gluebased gene-activated matrix. The preparation can be used is complete analogy to fibrin glue preparations that are used in the clinics. However, further improvements in transgene expression levels and persistence are required to yield cartilage regeneration in the osteochondral defect model chosen in this study.

The influence of the stable expression of BMP2 in fibrin clots on the remodelling and repair of osteochondral defects.

Growth factors like BMP2 have been tested for osteochondral repair, but transfer methods used until now were insufficient. Therefore, the aim of this study was to analyse if stable BMP2 expression after retroviral vector (Bullet) transduction is able to regenerate osteochondral defects in rabbits. Fibrin clots colonized by control or BMP2-transduced chondrocytes were generated for in vitro experiments and implantation into standardized corresponding osteochondral defects (n=32) in the rabbit trochlea. After 4 and 12 weeks repair tissue was analysed by histology (HE, alcian-blue, toluidine-blue), immunohistochemistry (Col1, Col2, aggrecan, aggrecan-link protein), ELISA (BMP2), and quantitative RT-PCR (BMP2, Col1, Col2, Col10, Cbfa1, Sox9). In vitro clots were also analysed by BMP2-ELISA, histology (alcian-blue), quantitative RT-PCR and in addition by electron microscopy. BMP2 increased Col2 expression, proteoglycan production and cell size in vitro. BMP2 transduction by Bullet was efficient and gene expression was stable in vivo over at least 12 weeks. Proteoglycan content and ICRS-score of repair tissue were improved by BMP2 after 4 and 12 weeks and Col2 expression after 4 weeks compared to controls. However, in spite of stable BMP2 expression, a complete repair of osteochondral defects could not be demonstrated. Therefore, BMP2 is not suitable to regenerate osteochondral lesions completely.

Osteochondral Transplantation in the Elbow Leads to Good Clinical and Radiologic Long-term Results: An 8- to 14-Year Follow-up Examination

Background: In the long-term follow-up after debridement, microfracture, or drilling of osteochondral lesions in the elbow, subsequent osteoarthritis is a problem. Osteochondral transplantation for these defects has become a more common procedure. However, long-term results are unknown. Purpose: This study was undertaken to evaluate long-term clinical and radiologic outcomes of advanced osteochondral lesions in the elbow treated with osteochondral transplantation. Study Design: Case series; Level of evidence, 4. Methods: The study included 8 patients with osteochondral lesions in the elbow who were treated by autologous osteochondral transplantation between 1996 and 2002. Patients (average age, 17 years) were evaluated pre- and postoperatively by Broberg-Morrey score to assess elbow function and by American Shoulder and Elbow Surgeons (ASES) score for pain analysis. In addition, radiographs (at the first postoperative day, and at 5-year and 10-year follow-up) and magnetic resonance images (8 to 12 weeks postoperatively, and at 5-year and 10-year follow-up) were made to evaluate the joint status. At last follow-up (range, 8-14 years postoperatively), 7 of 8 patients were seen for clinical examination and radiologic analysis. Results: The Broberg-Morrey score increased from an average of 75.9 ± 13.1 to 96.4 ± 2.4 and ASES score significantly improved as follows: worst pain, 7.9 ± 1.1 to 1.6 ± 1.9; rest pain, 3.14 ± 2.7 to 0.6 ± 1.5; weight-lifting pain, 7.6 ± 0.8 to 3.1 ± 1.6; and repetitive movement pain, 5.3 ± 2.4 to 1.6 ± 1.5. Compared with the contralateral side, there was a mean preoperative flexion lag of 12.5° ± 11.6°. At the final follow-up, flexion was free. The mean extension lag was reduced from average 5.4° ± 5.7° to 0°. Radiographs of 2 patients made at final follow-up showed mild signs of osteoarthritis (Kellgren and Lawrence grade I). Postoperative magnetic resonance images showed graft viability in all and a congruent chondral surface in 6 of 7 patients. Conclusion: Clinical long-term results after osteochondral transplantation in the elbow are good to excellent and comparable with midterm results in the literature. Therefore, this technique is a reliable option for satisfactory long-term results regarding treatment of advanced osteochondral lesions in the elbow.

Isolated and Combined Medial Patellofemoral Ligament Reconstruction in Revision Surgery for Patellofemoral Instability A Prospective Study

Background: Persistent pain and redislocations after surgical treatment of patellofemoral instability are described in up to 40% of patients. However, prospective outcome data about revision surgery are missing. Purpose: To evaluate the clinical outcome after revision medial patellofemoral ligament (MPFL) reconstruction using isolated and combined procedures, with a follow-up of 24 months. Study Design: Case series; Level of evidence, 4. Methods: Study participants were 42 patients (median age, 22 years; range, 13-46 years) who underwent revision surgery between January 2007 and December 2009 because of persistent patellofemoral instability after a mean of 1.8 previous failed surgical interventions (lateral release, medial imbrication/vastus medialis obliquus distalization, medialization of the tuberosity). An isolated MPFL reconstruction was performed in 15 cases, while a combination procedure was performed in 27 cases. The clinical results were evaluated preoperatively and 24 months postoperatively using the International Knee Documentation Committee (IKDC), Kujala, and Tegner scores as well as a subjective questionnaire. Patellar shift, tilt, and height, as well as level of degeneration, were defined preoperatively and at the latest follow-up on plain radiographs and magnetic resonance imaging. Results: At 24-month follow-up, 87% of the patients were satisfied or very satisfied with the treatment. No apprehension or redislocation was reported at follow-up, and there was a significant decrease in pain during daily activities. There were significant improvements (P < .001) in IKDC (from 50 to 80), Kujala (from 51 to 85), and Tegner scores (from 2.4 to 4.9). Patellar shift, tilt, and height decreased significantly (P < .05) to anatomic values, and there was no aggravation to the level of pre-existing degeneration. No significant difference was noticed between the isolated and combined procedures. Conclusion: As patellofemoral instability is a multifactorial problem, revision surgery should be indicated only after a comprehensive examination. The results of this study show that MPFL reconstruction, alone or in combination, seems to be an effective treatment for recurrent patellar dislocations after a failed previous surgery, leading to significant increases in stability and functionality as well as a reduction in pain.

Therapie der patellofemoralen Arthrose

ZusammenfassungBis heute gehört die Therapie der patellofemoralen Arthrose (PFA) zu den noch nicht vollkommen erschlossenen orthopädischen Gebieten. Die größte Herausforderung hierbei ist im Gegensatz zu Arthrosen anderer Gelenke die Bestimmung der Ätiologie. Dazu ist eine ausführliche Diagnose bzgl. der Anamnese, Lokalisation und Begleiterkrankungen notwendig, denn die PFA kann aufgrund einer Vielzahl von Pathomorphologien entstehen. Im Gegensatz zu Degenerationen in anderen Bereichen des Kniegelenks ist die Ätiologie der PFA in den seltensten Fällen traumatisch begründet. Daher zeigen Knorpeltherapien, die in anderen Gelenkanteilen erfolgreich angewendet werden, bei der Behandlung der PFA weniger zufrieden stellende Ergebnisse.Da bis heute keine Studien existieren, die den Erfolg verschiedener Therapieformen in Abhängigkeit der Arthroseentstehung betrachtet haben, gibt es auch keinen Behandlungsstandard. Es erscheint aber trotzdem notwendig und sinnvoll, nicht nur den Knorpelschaden, sondern wenn möglich auch die ursächliche Pathologie zu beheben. Unter diesem Gesichtspunkt ist es dann auch gerechtfertigt, bei jüngeren Patienten mit einer ausgeprägten Trochleadysplasie und in der Folge ausgebildeten instabilitätsbedingten Arthrose einen Oberflächenersatz zu implantieren. Damit wird nicht nur die Arthrose, sondern auch die Instabilität durch Schaffung einer physiologischen Trochlea behoben.Zusammengefasst hängt der Therapieerfolg der PFA von deren Ursache ab. Während man direkte, traumatische Schäden mit einer isolierten Knorpeltherapie erfolgreich behandeln kann, muss bei der größeren Zahl der indirekt und atraumatisch entstandenen Schäden eine Kombinationstherapie mit Behandlung der auslösenden Faktoren bedacht werden.AbstractEven today the treatment of patellofemoral arthritis (PFA) has still not been fully developed and the greatest challenge, in contrast to arthrosis in other joints, is to define the etiology. It is most important to decide whether the degeneration is caused by a simple local trauma or by an ongoing overload or malalignment. Therefore, a comprehensive diagnostic concerning the localization and the etiology has to be performed. In contrast to degeneration in other regions of the knee joint, the etiology of PFA rarely has a traumatic origin. Therefore, chondral forms of treatment, which can be successfully used in other joint regions show less satisfactory results for PFA.As there are no studies which have investigated the the success of various forms of therapy of cartilage defects in correlation to the pathomorphology or investigated combined techniques, there is no gold standard. However, to achieve satisfying results, it is necessary to treat not only the cartilaginous or osteochondral defects but also the underlying pathomorphology. Therefore, even in young patients with severe patellofemoral degeneration due to a trochlear dysplasia with permanent patellar dislocations and instability, it would seem justified to implant a patellofemoral prosthesis. In this way the hereditary dysplasia of the trochlea can be rectified and instability would be corrected in addition to the degeneration.In summary, the optimal treatment depends on the extent and localization of the cartilage defect. Whereas direct defects of the cartilage caused by trauma can be successfully treated with an isolated chondral therapy, a combination therapy with treatment of the underlying cause must be considered for the majority of indirect and atraumatic injuries.

Eine seltene Kombinationsverletzung im Rahmen einer Schulterinstabilität

ZusammenfassungTypischerweise ist die Glenolabral-articular-disruption- (GLAD-)Läsion nicht mit einer Instabilität kombiniert und weist neben dem Knorpeldefekt lediglich oberflächliche Einrisse am anteroinferioren Labrum auf. Im vorgestellten Fall wird eine seltene Kombinationsverletzung beschrieben, bei der es durch eine chronische Überbelastung bei bestehender GLAD-Läsion zu einer symptomatischen Instabilität kam. Therapeutisch konnten der kraniale Labrumkomplex unter Erhalt der langen Bizepssehne refixiert und der kaudale Labrumkomplex mittels Interpositionsarthroplastik augmentiert werden. Ein begleitender Knorpelschaden im Bereich des Humeruskopfs wurde nicht therapeutisch angegangen. Die Weiterentwicklung der arthroskopischen Techniken erlaubt die Behandlung einer Vielzahl instabilitätsassoziierter pathoanatomischer Befunde.AbstractShoulder instability may veil various patho-anatomic findings. A case with a rare combination of patho-anatomic lesions is presented. In a patient with antero-inferior instability arthroscopy confirmed a superior labrum anterior-to-posterior (SLAP IV) lesion and a glenolabral articular disruption (GLAD) as well as a concomitant chondral injury to the apex of the humeral head. Stabilization of the labral complex was achieved arthroscopically. The osteochondral defect of the glenoid was addressed by interposition arthroplasty. Arthroscopic treatment of shoulder instability offers an individualized approach to a broad variety of patho-anatomic findings.