Feasibility Study to Determine if Microfracture Surgery Using Water Jet Drilling Is Potentially Safe for Talar Chondral Defects in a Caprine Model.

OBJECTIVE: Surgical microfracture is considered a first-line treatment for talar osteochondral defects. However, current rigid awls and drills limit access to all locations in human joints and increase risk of heat necrosis of bone. Using a flexible water jet instrument to drill holes can improve the reachability of the defect without inducing thermal damage. The aim of this feasibility study is to determine whether water jet drilling is potentially safe compared with conventional microfracture awls by studying side effects and perioperative complications, as well as the quality of cartilage repair tissue. DESIGN: Talar chondral defects with 6-mm diameter were created bilaterally in 6 goats (12 samples). One defect in each goat was treated with microfracture created with conventional awls, the contralateral defect was treated with holes created with 5-second water jet bursts at a pressure of 50 MPa. Postoperative complications were recorded and after 24 weeks analyses were performed using the ICRS (International Cartilage Repair Society) macroscopic score and modified O'Driscoll histological score. RESULTS: Several practical issues using the water jet in the operating theatre were noted. Water jet drilling resulted in fibrocartilage repair tissue similar to the repair tissue from conventional awls. CONCLUSIONS: These results suggest that water jet drilling gives adequate fibrocartilage repair tissue. Furthermore, the results highlight essential prerequisites for safe application of surgical water jet drilling: stable water pressure, water jet beam coherence, stable positioning of the nozzle head when jetting, and minimizing excessive fluid extravasation.

Three-Dimensional Registration of Freehand-Tracked Ultrasound to CT Images of the Talocrural Joint.

A rigid surface⁻volume registration scheme is presented in this study to register computed tomography (CT) and free-hand tracked ultrasound (US) images of the talocrural joint. Prior to registration, bone surfaces expected to be visible in US are extracted from the CT volume and bone contours in 2D US data are enhanced based on monogenic signal representation of 2D US images. A 3D monogenic signal data is reconstructed from the 2D data using the position of the US probe recorded with an optical tracking system. When registering the surface extracted from the CT scan to the monogenic signal feature volume, six transformation parameters are estimated so as to optimize the sum of monogenic signal features over the transformed surface. The robustness of the registration algorithm was tested on a dataset collected from 12 cadaveric ankles. The proposed method was used in a clinical case study to investigate the potential of US imaging for pre-operative planning of arthroscopic access to talar (osteo)chondral defects (OCDs). The results suggest that registrations with a registration error of 2 mm and less is achievable, and US has the potential to be used in assessment of an OCD' arthroscopic accessibility, given the fact that 51% of the talar surface could be visualized.

What quantitative mechanical loading stimulates in vitro cultivation best?

Articular cartilage has limited regeneration capacities. One of the factors that appear to affect the in vitro cultivation of articular cartilage is mechanical stimulation. So far, no combination of parameters has been identified that offers the best results. The goal is to review the literature in search of the best available set of quantitative mechanical stimuli that lead to optimal in vitro cultivation.The databases Scopus and PubMed were used to survey the literature, and strict in- and exclusion criteria were applied regarding the presence of quantitative data. The review was performed by studying the type of loading (hydrostatic compression or direct compression), the loading magnitude, the frequency and the loading regime (duration of the loading) in comparison to quantitative evidence of cartilage quality response (cellular, signaling and mechanical).Thirty-three studies met all criteria of which 8 studied human, 20 bovine, 2 equine, 1 ovine, 1 porcine and 1 canine cells using four different types of cultivated constructs. Six studies investigated loading magnitude within the same setup, three studies the frequency, and seven the loading regime. Nine studies presented mechanical tissue response. The studies suggest that a certain threshold exits for enhanced cartilage in vitro cultivation of explants (>20 % strain and 0.5 Hz), and that chondrocyte-seeded cultivated constructs show best results when loaded with physiological mechanical stimuli. That is a loading pressure between 5-10 MPa and a loading frequency of 1 Hz exerted at intermittent intervals for a period of a week or longer. Critical aspects remain to be answered for translation into in vivo therapies.

Comparison of optical coherence tomography and histopathology in quantitative assessment of goat talus articular cartilage.

BACKGROUND AND PURPOSE: Optical coherence tomography (OCT) is a light-based imaging technique suitable for depiction of thin tissue layers such as articular cartilage. Quantification of results and direct comparison with a reference standard is needed to confirm the role of OCT in cartilage evaluation. MATERIALS AND METHODS: Goat talus articular cartilage repair was assessed quantitatively with OCT and compared with histopathology using semi-automated analysis software. Osteochondral defects were created centrally in goat tali with subsequent healing over 24 weeks. After sacrifice, the tali were analyzed using OCT and processed into histopathology slides. Cartilage thickness, repair tissue area, and surface roughness were measured. Also, light attenuation coefficient measurements were performed to assess differences in the properties of healthy tissue and repair tissue. RESULTS: Intra-class correlation coefficients for resemblance between the 2 techniques were 0.95 (p < 0.001) for thickness, 0.73 (p = 0.002) for repair tissue area, and 0.63 (p = 0.015) for surface roughness. Light attenuation differed significantly between healthy cartilage (8.2 (SD 3.9) mm(-1)) and repair tissue (2.8 (SD 1.5) mm(-1)) (p < 0.001). INTERPRETATION: Compared to histopathology as the standard reference method, OCT is a reproducible technique in quantitative analysis of goat talus articular cartilage, especially when assessing cartilage thickness and to a lesser extent when measuring repair tissue area and surface roughness. Moreover, differences in local light attenuation suggest measurable variation in tissue structure, enhancing the clinical applicability of quantitative measurements from cartilage OCT images.

Is technique performance a prognostic factor in bone marrow stimulation of the talus?

Although results of bone marrow stimulation in osteochondral defects of the talus (OCLT) have been satisfactory, the technique performance has not yet been subjected to review as a prognostic factor. The aim of this systematic review is to determine whether variation within technique influences outcome of bone marrow stimulation for OCLT. Electronic databases were searched for articles on OCLT treated with bone marrow stimulation techniques, providing a technique description. Six articles on microfracture were included (198 patients). Lesion size averaged 0.9 cm (2) to 4.5 cm (2), and follow-up varied from 2 to 6 years. Key elements were removal of unstable cartilage, hole depth variation between 2 and 4 mm until bleeding or fat droplets occurred, and a distance between the created holes of 3 to 4 mm. The success rate (excellent/good results by any clinical outcome score) was 81%. There is a vast similarity in the technique with similar outcomes as in previous general reviews; therefore variation in technique as currently described in the literature does not seem to influence the outcome of bone marrow stimulation for OCLT. Whether the instruments used or the hole depth and geometry influence clinical outcome remains to be determined. Microfracture is safe and effective for OCLTs smaller than 15 mm. However, in this review, only 81% of patients obtained satisfactory results. Larger clinical trials are needed with clearly defined patient groups, technique descriptions, and reproducible outcome measures to provide insight in the specific indications and the preferred technique of bone marrow stimulation.

Surgical treatment of chronic retrocalcaneal bursitis.

PURPOSE: The purpose of this systematic review was to analyze the results of surgical treatments for chronic retrocalcaneal bursitis (RB). METHODS: Medline, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Embase, and the Cochrane Library (1945 to December 2010) were systematically searched for the following terms: calcaneal AND (prominence OR exostosis) OR ((retrocalcaneal OR calcan(*)) AND (burs(*) OR exosto(*) OR prominence)) OR Haglund[tw] OR Haglund's[tw] OR ((retrocalcaneal OR calcan(*)) AND (ostectom(*) OR osteotom(*) OR resect(*))). Therapeutic studies on 10 or more subjects with RB were eligible. Quality was assessed by use of the GRADE scale and Downs and Black scale. RESULTS: Of 876 reviewed abstracts, 15 trials met our inclusion criteria evaluating 547 procedures in 461 patients. Twelve trials reported an open surgical technique; three studies evaluated endoscopic techniques. Differences in patient satisfaction favored the endoscopic technique. The complication rate differed substantially, favoring endoscopic surgery over open surgery. CONCLUSIONS: There are many different surgical techniques to treat RB. Regardless of technique, resecting sufficient bone is essential for a good outcome. Even though the level of evidence of included studies is relatively low, it can be concluded that endoscopic surgery is superior to open intervention for RB. More evidence is a necessity to be more conclusive regarding the best surgical treatment. LEVEL OF EVIDENCE: Level IV, systematic review of Level III and IV studies.