Jan Philipp Petersen

Present and Future Therapies of Articular Cartilage Defects

AbstractBackground: Until today, no universally successful therapy to treat substantial articular cartilage defects has been available. Numerous therapeutic approaches can only improve clinical symptoms of joint lesions, but cannot stimulate the regenerative and reactive capacity of the biological tissue in the defect, and, thus, cannot restore an articular surface capable of functional load bearing. Some other therapeutic options promised impressing results at the beginning, but did not withstand the process of a closer investigation. Even after laborious, invasive and expensive therapies, patients still complain about pain, joint effusions, restricted movement, or articular blockage. Established and Novel Therapies: The aim of all therapeutic procedures to treat patients with damaged articular cartilage is to reconstruct the integrity of the articular cartilage surface in order to enable them to live an unrestricted painless professional and private life. This article gives an overview of the clinically established procedures, their indications and the present long-term results, as well as a crucial look on the limitations of each approach. Novel therapies, which integrate molecular biology techniques and tissue engineering into transplantation surgery, are introduced and analyzed in terms of their capability and future potential.

Accuracy Analysis of a Novel Electromagnetic Navigation Procedure Versus a Standard Fluoroscopic Method for Retrograde Drilling of Osteochondritis Dissecans Lesions of the Knee

Background: Retrograde drilling for osteochondritis dissecans (OCD) remains a challenging operation. Purpose: A novel radiation-free electromagnetic navigation system (ENS)–based method was developed and its feasibility and accuracy for retrograde drilling procedures evaluated and compared with the standard freehand fluoroscopic method in an experimental setting. Study Design: Controlled laboratory study. Methods: A controlled laboratory study with 16 standard freehand fluoroscopically and 16 electromagnetically guided retrograde drilling procedures was performed on 8 cadaveric human knees. Four artificial cartilage lesions (2 on each condyle) were set per knee. Drilling accuracy was determined by final distance from the tip of the drill bit to the tip of the probe hook (D1) and distance between the tip of the drill and the marked lesion on the cartilage surface (D2). Intraoperative fluoroscopy exposure times were documented, as were directional readjustments or complete restarts. All procedures were timed using a stopwatch. Results: Successful retrograde drilling was accomplished in all 16 cases using the novel ENS-based method and in 11 cases using the standard fluoroscopic technique. The overall mean time for the fluoroscopy-guided procedures was 10 minutes 55 seconds ± 3 minutes 19 seconds and for the ENS method was 5 minutes 34 seconds ± 38 seconds, providing a mean time benefit of 5 minutes 35 seconds (P < .001). Mean D1 was 3.8 ± 1.6 mm for the standard and 2.3 ± 0.6 mm using the ENS technique (P = .021), and mean D2 was 2.5 ± 1.3 mm for the standard and 0.9 ± 0.7 mm for the ENS-based method (P < .001). Conclusion: Compared with the standard fluoroscopic technique, the novel ENS-based method used in this study showed superior accuracy, required less time, and utilized no radiation. Clinical Relevance: The novel method improves a standard operating procedure in terms of accuracy, operation time for the retrograde drilling procedure, and radiation exposure.

High incidence of osteochondral lesions after open reduction and internal fixation of displaced ankle fractures: Medium-term follow-up of 100 cases.

BACKGROUND The incidence of osteochondral lesions (OCLs) in association with displaced ankle fractures has only been examined in two previous studies. In both studies magnetic resonance imaging (MRI) was performed prior to open reduction and internal fixation (ORIF). Because MRI may overdiagnose or overestimate the extent of OCLs in an acute trauma setting the aim of this study was to determine the incidence of OCLs after ORIF of displaced ankle fractures using MRI at medium-term follow-up, and to analyse if the severity of fracture or the clinical outcome correlates with the incidence of OCLs. PATIENTS AND METHODS Following institutional review board approval a total of 100 patients (mean age, 41.3 years; range, 17.9-64.3 years) with a displaced ankle fracture who had undergone ORIF according to the AO principles were included in this study. The American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score was used to quantify the clinical outcome and MR images were evaluated for OCLs of the talus and distal tibia after a mean of 34.5 months (range, 17.5-54.1 months). RESULTS OCLs were found in 40.4% of the patients. Logistic regression revealed a significant correlation between the severity of fracture and the incidence of OCLs. Patients with a trimalleolar fracture (p=0.04) or an ankle fracture dislocation (p=0.003) had a significantly higher risk for developing an OCL compared to those with a type B fracture. Logistic regression also demonstrated a significant correlation between the clinical outcome (AOFAS score) and the incidence of OCLs (p=0.01). The risk for developing an OCL increases up to 5.6% when the AOFAS score decreases by one point. CONCLUSION OCLs were frequently found in association with acute ankle fractures at medium-term follow-up, and the severity of fracture was associated with an increased number of OCLs. Considering the disadvantages of MRI including the high cost and limited availability, the results of this study may help to explain why anatomic surgical realignment of displaced ankle fractures may still be associated with poor clinical outcomes.

Retrograde Drilling of Talar Osteochondritis Dissecans Lesions: A Feasibility and Accuracy Analysis of a Novel Electromagnetic Navigation Method Versus a Standard Fluoroscopic Method

PURPOSE A novel method using an electromagnetic navigation system (ENS) was developed, and its feasibility and accuracy for retrograde drilling procedures were evaluated and compared with the standard freehand fluoroscopic method in an experimental setting. METHODS A controlled laboratory study of 16 standard freehand fluoroscopically guided and 16 electromagnetically navigated retrograde drilling procedures was performed on 4 cadaveric human ankle joints. Four artificial cartilage lesions were consecutively set, 2 on the medial and 2 on the lateral talar dome. Drilling accuracy was measured in terms of the distance from the final position of the drill bit to the tip of the probe hook and the distance between the tip of the drill bit and the center of the cartilage lesion on the articular cartilage surface. Intraoperative fluoroscopy exposure times were documented, as were readjustments of drilling directions or complete restarts. All procedures were timed with a stopwatch. RESULTS Successful retrograde drilling was accomplished in 12 cases with the standard fluoroscopy-guided technique and in all 16 ENS-guided procedures. The overall mean time for the fluoroscopy-guided procedures was 660.00 ± 239.87 seconds and the overall mean time for the ENS method was 308.06 ± 54.03 seconds, providing a mean time benefit of 420.13 seconds. The mean distance from the final position of the drill bit to the tip of the probe hook was 3.25 ± 1.29 mm for the standard method and 2.19 ± 0.54 mm for the ENS method, and the mean distance between the tip of the drill bit and the center of the cartilage lesion on the articular cartilage surface was 2.50 ± 0.97 mm for the standard method and 0.88 ± 0.81 mm for the ENS method. CONCLUSIONS Compared with the standard fluoroscopic technique, the ENS method used in this study showed higher accuracy and a shorter procedure time and required no X-ray radiation. CLINICAL RELEVANCE The novel method considerably improves on the standard operating procedure in terms of safety, operation time, and radiation exposure.

Management of traumatic spinopelvic dissociations: review of the literature

PurposeSpinopelvic dissociation is a rare high-energy injury pattern in adults associated with high morbidity and an increased rate of neurological deficits. The purpose of this article is the conception of fracture type-associated treatment recommendations.MethodsThis article is based on our own experience with spinopelvic dissociations and a review of the current literature.ResultsBilateral vertical plus an optional transverse fracture component configures spinopelvic dissociations as “U”- or “H”-shaped, with the result of a spinopelvic dissociation. “Y”-, “T”- or “II”-shaped fractures do not necessarily belong to this entity but can be subsumed to this entity in a wider sense. The surgical treatment of these injuries remains challenging. Initial haemodynamic stabilisation represents the main goal of primary care until definitive treatment can be performed. Anatomical reduction is demanding and even more complex in fracture areas with large comminution. Surgical treatment options depend on the fracture type, including transsacral screws, sacral banding and spinopelvic fixation, plus combinations of these procedures.ConclusionsSpinopelvic dissociations remain highly complex injuries. “U”- and “H”-shaped fractures usually require triangular fixation, whereas “II”-, “Y”- and “T”-shaped fractures might be sufficiently stabilised with transsacral screws.

Knorpel aus dem Labor — eine Sackgasse?

ZusammenfassungKnorpeldefekte sind bei jüngeren und aktiven Patienten für erhebliche Funktionseinschränkungen am Bewegungs- und Stützorgan verantwortlich. Mechanismen für eine Spontanheilung existieren nicht. Aktuelle biologische Therapieansätze reparieren durch lokale Regeneration oder Umsetzung von Gelenkflächenstanzen mit begrenztem Erfolg. Zell- und Gewebekulturtechniken (Tissue Engineering) ermöglichen die Produktion von Gelenkflächenimplantaten aus körpereigenen Zellen, wie hier an einem Tiermodell dokumentiert. Der gesamte Prozess der Zellvermehrung und der Knorpelgewebebildung findet im Bioreaktor statt. Die Einjahresergebnisse bestätigen den Erfolg von Knorpel aus dem Labor. Ob sich das Tissue Engineering als Therapie durchsetzen wird, hängt neben dem weiteren Forschungsaufwand aber auch von gesundheitspolitischen Bedingungen ab. Würde das Verfahren trotz medizinischer Notwendigkeit am Markt nicht realisiert, werden die Kenntnisse, die bei seiner Entwicklung gewonnen wurden, die lokale In-situ-Regeneraion ermöglichen, wobei das Gelenk selber als Bioreaktor des Tissue Engineering dient, wenn hindernde Faktoren ausgeschaltet sind.AbstractCartilage defects are responsible in younger and active patients for substantial functional restrictions. Mechanisms for spontaneous healing do not exist. Current biological therapy concepts repair by local regeneration or transplantation of joint segments with limited success. Cell and tissue engineering techniques allow the production of joint surface implants from autologous cells, as documented in an animal model. The entire process of the proliferation and the cartilage tissue formation takes place in a bioreactor. The 1-year follow-up confirms the success of cartilage from the bioreactor. Whether tissue engineering will become generally accepted as therapy depends, apart from the still necessary research expenditure, on conditions of healthcare policy. If the procedure is not realized despite its medical usefulness in the market, the knowledge gained through its development will make local in situ regeneration possible, whereby the joint itself serves as a bioreactor for tissue engineering if preventing factors are eliminated.

Prediction of Meniscal and Ligamentous Injuries in Lateral Tibial Plateau Fractures Based on Measurements of Lateral Plateau Widening on Multidetector Computed Tomography Scans

Background The influence of increasing lateral plateau widening on the frequency of meniscal and ligamentous lesions in lateral tibial plateau fractures has been examined in very few studies using plain radiographs. Because the amount of this parameter cannot be measured accurately on plain radiographs, the purpose of this survey was to look for a possible correlation between the extent of lateral plateau widening, as measured on multidetector CT (MDCT) scans, and different soft-tissue injuries determined from magnetic resonance imaging (MRI). Materials and Methods 55 patients with a lateral tibial plateau fracture were included in this retrospective case series. Patient age averaged 52.6 years (SD = 18.0). The degree of lateral plateau widening was measured on CT images. MRIs were screened for meniscal and ligamentous injuries. Results We found a significant effect of increasing lateral plateau widening on the incidence of lateral meniscus lesions (P = 0.021), lateral collateral ligament tears (P = 0.047), and the overall quantity of meniscal and ligamentous lesions (P = 0.001). Discussion MRIs are not widely used as a diagnostic tool in lateral plateau fractures of the tibia. Reasons might be the costs and the fact that it is a time-consuming examination. The results of this study may help to estimate the probability of specific soft-tissue lesions in lateral tibial plateau fractures based on measurements of lateral plateau widening on MDCT scans, and they may guide the decision for additional MRI and/or arthroscopically assisted repair.

Osteochondrale Transplantation@@@Osteochondral transplantation: Ein bewährtes Therapieverfahren für größere Knorpeldefekte an Knie und OSG@@@A reliable method for large cartilaginous defects of the knee and ankle

ZusammenfassungDie Aussage des englischen Chirurgen W. Hunter von 1743, dass Knorpelschäden sehr unangenehm sind, nie heilen und schwieriger zu behandeln sind als Knochenschäden, trifft auch heute noch zu. Es existiert nach wie vor kein allgemein und umfassend erfolgreiches Konzept, das zu einer vollständigen Ausheilung der Defekte mit uneingeschränkter Wiederaufnahme der sportlichen oder alltäglichen Betätigungen führt. Derzeit werden kleinere Defekte durch das Microfracture-Verfahren, größere Läsionen mittels Knorpel-Knochen-Transplantation behandelt, während bei diffusen Arthrosen gesamter Gelenke meist der radikale endoprothetische Oberflächenersatz bzw. bei jüngeren Patienten eher eine Arthrodese zum Einsatz kommen. Die autogene Knorpel-Knochen-Transplantation ist ein viel versprechendes Verfahren mit guten Resultaten, die u. a. darauf zurückzuführen sind, dass der Defekt durch Zylinder von hyalinem, gesundem Knorpel mit den idealtypischen histologischen und biomechanischen Eigenschaften des Originalknorpels ersetzt wird. Weitere Vorteile sind die im Vergleich zu anderen Verfahren der Knorpel-Knochen-Transplantation geringe Entnahmemorbidität sowie die sofort mögliche Mobilisierung und Vollbelastung. Zudem ist das Verfahren kostengünstig.AbstractThe statement made by the English surgeon W. Hunter in 1743 that“ulcerated cartilage is a very troublesome desease, its cure is more difficult than that of carious bone and when destroyed, it is never recovered” still applies to a great extent today. There is still no generally and comprehensively successful concept capable of producing complete healing of the damage with unrestricted resumption of sports or daily activities. Currently, small defects are treated using the microfracture method, larger lesions using osteochondral transplantation, while diffuse osteoarthritis of the whole joint usually require radical endoprosthetic resurfacing or, in younger patients, preferably arthrodesis. Autogenous cartilage-bone transplantation is a very promising technique with good results due to the fact that the defect is replaced by hyaline cylinders of healthy cartilage with the ideal histological and biomechanical characteristics of the native cartilage. Further advantages of the cartilage-bone transplantation method in comparison to other methods include low donor site morbidity, as well as immediate load-bearing and mobility. And the procedure is cost-saving.