Accuracy of navigated surgery of the pelvis after surface matching with an a-mode ultrasound probe

Computer-aided surgery (CAS) allows for real-time intraoperative feedback resulting in increased accuracy, while reducing intraoperative radiation. CAS is especially useful for the treatment of certain pelvic ring fractures, which necessitate the precise placement of screws. Flouroscopy-based CAS modules have been developed for many orthopedic applications. The integration of the isocentric flouroscope even enables navigation using intraoperatively acquired three-dimensional (3D) data, though the scan volume and imaging quality are limited. Complicated and comprehensive pathologies in regions like the pelvis can necessitate a CT-based navigation system because of its larger field of view. To be accurate, the patient's anatomy must be registered and matched with the virtual object (CT data). The actual precision within the region of interest depends on the area of the bone where surface matching is performed. Conventional surface matching with a solid pointer requires extensive soft tissue dissection. This contradicts the primary purpose of CAS as a minimally invasive alternative to conventional surgical techniques. We therefore integrated an a-mode ultrasound pointer into the process of surface matching for pelvic surgery and compared it to the conventional method. Accuracy measurements were made in two pelvic models: a foam model submerged in water and one with attached porcine muscle tissue. Three different tissue depths were selected based on CT scans of 30 human pelves. The ultrasound pointer allowed for registration of virtually any point on the pelvis. This method of surface matching could be successfully integrated into CAS of the pelvis.

Subcellular distribution of the insulin-like growth factor (IGF) binding proteins (IGFBPs) 2 and 3 in articular chondrocytes

The insulin-like growth factor (IGF) is a major anabolic regulator in articular cartilage. The IGF-binding proteins (IGFBPs) are increased during osteoarthritis (OA), but the function of the later proteins remains unknown. In general, the IGFBPs are pluripotential effectors capable of IGF regulation and of acting on their own to control key cell functions, including survival and proliferation. The independent functions are often associated with their cell location, and therefore this study explores the distribution of IGFBP-2 and IGFBP-3 in articular chondrocytes. Immunohistochemistry was used to localize IGFBP-2 in normal human articular cartilage. Bovine chondrocytes were used for subcellular fractionation (hypotonic cell lysis) under nonreducing conditions and nuclear purification (centrifugation on sucrose cushions). Cell fraction markers and IGFBPs were assayed in the subcellular fractions by Western immunoblot. The IHC results showed association of IGFBP-2 with chondrocytes, but not with the nuclei. Subcellular fractionation of isolated chondrocytes yielded intact nuclei as assessed at the light microscopic level; the nuclear marker histone H1 was exclusively associated with this fraction. More than 90% of the cytoplasmic marker GAPDH and all the detectable IGFBP-2 were in the cytoplasmic fraction. Immunoreactive IGFBP-3 was found in the cytoplasmic and peri-nuclear/nuclear fractions. Chondrocytes contain intracellular IGFBP-2 and IGFBP-3 but only IGFBP-3 is associated with nuclei. This suggests the hypothesis that the actions of these IGFBPs in articular cartilage extend beyond the classic modulation of IGF receptor action.

Accelerated hypertrophic chondrocyte kinetics in GDF-7 deficient murine tibial growth plates

The Growth/Differentiation Factors (GDFs) are a subgroup of the Bone Morphogenetic Proteins (BMPs) well known for their role in joint formation and chondrogenesis. Mice deficient in one of these signaling molecules, GDF-5, have recently been shown to exhibit a decreased rate of endochondral bone growth in the proximal tibia due to a significantly longer hypertrophic phase duration. GDF-7 is a related family member, which exhibits a high degree of sequence identity with GDF-5. The purpose of the present study was to determine whether GDF-7 deficiency also alters the endochondral bone growth rate in mice and, if so, how this is achieved. Stereologic and cell kinetic parameters in proximal tibial growth plates from 5-week-old female GDF-7 -/- mice and wild type control littermates were examined. GDF-7 deficiency resulted in a statistically significant increase in growth rate (+26%; p = 0.0084) and rate of cell loss at the chondrosseous junction (+25%; p = 0.0217). Cells from GDF-7 deficient mice also exhibited a significantly shorter hypertrophic phase duration compared to wild type controls (-27%; p = 0.0326). These data demonstrate that, in the absence of GDF-7, the rate of endochondral bone growth is affected through the modulation of hypertrophic phase duration in growth plate chondrocytes. These findings further support a growing body of evidence implicating the GDFs in the formation, maturation, and maintenance of healthy cartilage.

Tissue neogenesis and STRO-1 expression in immature and mature articular cartilage

This study determined the potential for neotissue formation and the role of STRO-1+ cells in immature versus mature articular cartilage. Cartilage explants from immature and mature bovine knee joints were cultured for up to 12 weeks and stained with safranin-O, for type II collagen and STRO-1. Bovine chondrocyte pellet cultures and murine knee joints at the age of 2 weeks and 3 months, and surgically injured cartilage, were analyzed for changes in STRO-1 expression patterns. Results show that immature explants contained more STRO-1+ cells than mature explants. After 8 weeks in culture, immature explants showed STRO-1+ cell proliferation and newly formed tissue, which contained glycosaminoglycan and type II collagen. Mature cartilage explants showed only minimal cell expansion and neotissue formation. Pellet cultures with chondrocytes from immature cartilage showed increased glycosaminoglycan synthesis and STRO-1+ staining, as compared to pellets with mature chondrocytes. The frequency of STRO-1+ cells in murine knee joints significantly declined with joint maturation. Following surgical injury, immature explants had higher potential for tissue repair than mature explants. In conclusion, these findings suggest that the high percentage of STRO-1+ cells in immature cartilage changes with joint maturation. STRO-1+ cells have the potential to form new cartilage spontaneously and after tissue injury. (c) 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

[Implementation of a routine gradual psycho-diagnostic programme in somatic rehabilitation centres - results of a pilot study]

STUDY AIM: A pilot study was conducted to implement and evaluate a routine gradual psycho-diagnostic programme to improve diagnostics and treatment of mental disorders in somatic rehabilitation centres. First of all, implementation strategies were acquired in trainings together with psychologists and physicians. The psycho-diagnostic programme consists of a screening instrument (PHQ-9) designed to permit time-effective detection of comorbid mental disorders. Besides evaluation of the training, the aim of the study was to analyze the extent to which it is possible to implement the routine gradual psycho-diagnostic programme in practice. Additionally, it was intended to identify beneficial and obstructive conditions for implementation. METHODOLOGY: The pilot study was conducted in two orthopaedic and one cardiological rehabilitation centre. The training was evaluated directly after its completion using a questionnaire. Three months after its implementation, the introduction of the psycho-diagnostic programme was evaluated using interviews with n=11 physicians and psychologists. RESULTS: The training was rated positively by the participants . Implementation of the entire gradual psycho-diagnostic programme was possible in one centre and to some degree in the other two. Beneficial for implementation were a frank organisational climate, sufficient time resources, and physicians' biopsychosocial understanding of disease. A dismissive attitude towards psycho-diagnostics, little communication between staff members, little perceived advantage for one's own work and fear to stigmatise patients by psychiatric diagnoses were obstructive. CONCLUSION: Essential for a successful implementation are sufficient time and personal resources, a motivation for change in staff and centre management, and a positive attitude regarding psycho-diagnostics in clinic staff. Furthermore, flexibility in implementation strategies and the opportunity to participate in the implementation process are important.

Arthroscopically assisted removal of intraosseous ganglion cysts of the distal tibia

Intraosseous ganglia of the distal tibia are rare. We evaluated the feasibility of surgically treating these lesions with an arthroscopically assisted technique. Five patients with symptomatic distal tibial ganglia underwent surgical curettage and excision with this technique. All patients underwent débridement of the chondral lesion and hypertrophied synovial lining when present, probing of the portal to the ganglion, and subsequently thorough curettage with bone grafting performed through a cortical window made from a separate small incision. Biopsy confirmed the diagnosis in all patients. All patients had eventual relief of symptoms with good integration of bone graft at final followup. There were no recurrences at a minimum followup of 19 months (mean, 38.6 months; range, 19-69 months). Mean time for return to full function was 15.4 weeks (range, 8-17 weeks). There were no intraoperative or postoperative complications. The mean American Orthopaedic Foot and Ankle Society scores increased from 73 points (range, 67-77 points) preoperatively to 94 points (range, 90-100 points) postoperatively. Arthroscopically assisted surgical treatment of ganglia of the distal tibia in the appropriate patient is a reasonably simple technique that relieves symptoms and helps the patient to regain normal gait and full function with no recurrence (in our small series). LEVEL OF EVIDENCE: Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence.

Reliability of radiologic assessment of the fracture anatomy at the posterior tibial plafond in malleolar fractures

The aim of this study was to assess the ability to extract surgically relevant information from plain radiographs in trimalleolar fractures and to compare this with the information gathered from computed tomography (CT).

Reverse total shoulder arthroplasty

The radical changes in prosthetic design made in the mid 1980s transformed the historically poorly performing reverse ball-and-socket total shoulder prosthesis into a highly successful salvage implant for pseudoparalytic, severely rotator cuff-deficient shoulders. Moving the center of rotation more medial and distal as well as implanting a large glenoid hemisphere that articulates with a humeral cup in 155 degrees of valgus are the biomechanical keys to sometimes spectacular short- to mid-term results. Use of the reverse total shoulder arthroplasty device allows salvage of injuries that previously were beyond surgical treatment. However, this technique has a complication rate approximately three times that of conventional arthroplasty. Radiographic and clinical results appear to deteriorate over time. Proper patient selection and attention to technical details are needed to reduce the currently high complication rate.