Aims

Pigment epithelium-derived factor (PEDF) is known to induce several types of tissue regeneration by activating tissue-specific stem cells. Here, we investigated the therapeutic potential of PEDF 29-mer peptide in the damaged articular cartilage (AC) in rat osteoarthritis (OA).

Aims

The effects of remnant preservation on the anterior cruciate ligament (ACL) and its relationship with the tendon graft remain unclear. We hypothesized that the co-culture of remnant cells and bone marrow stromal cells (BMSCs) decreases apoptosis and enhances the activity of the hamstring tendons and tenocytes, thus aiding ACL reconstruction.

Aims

Acquired heterotopic ossification (HO) is a debilitating disease characterized by abnormal extraskeletal bone formation within soft-tissues after injury. The exact pathogenesis of HO remains unknown. It was reported that BRD4 may contribute to osteoblastic differentiation. The current study aims to determine the role of BRD4 in the pathogenesis of HO and whether it could be a potential target for HO therapy.

Aims

Whether to perform hybrid surgery (HS) in contrast to anterior cervical discectomy and fusion (ACDF) when treating patients with multilevel cervical disc degeneration remains a controversial subject. To resolve this we have undertaken a meta-analysis comparing the outcomes from HS with ACDF in this condition.

Wear and corrosion debris generated from total hip replacements (THR) can cause adverse local tissue reactions (ALTR) or osteolysis, often leading to premature implant failure. The tissue response can be best characterized by histopathological analysis, which accurately determines the presence of cell types, but is limited in the characterization of biochemical changes (e.g. protein conformation alteration). Fourier transform infrared micro-spectroscopy imaging (FTIRI) enables rapid analysis of the chemical structure of biological tissue with a high spatial resolution, and minimal additional sample preparation. The data provides the most information through multivariate method carried out by hierarchical clustering analysis (HCA).

It is the goal of this study to demonstrate the beneficial use of this multivariate approach in providing pathologist with biochemical information from cellular and subcellular organization within joint capsule tissue retrieved from THR patients.

Joint capsule tissue from 2 retrieved THRs was studied. Case 1: a metal-on-polyethylene THR, and Case 2: a dual modular metal-on-metal THR. Prior to FTIRI analysis, tissue samples were formalin-fixed paraffin-embedded and 5μm thick microtome sectioned samples were prepared and mounted on BaF₂ discs and deparaffinized. FTIRI data were collected using high-definition transmission mode (pixel size: ∼1.1 μm²). Hyperspectral images were exported to CytoSpec V2.0.06 for processing and reconstruction into pseudo-color maps based on cluster assignments.

Case 1 exhibited a strong presence of lymphocytes and macrophages (Fig. 1a). Since the process of taking second derivatives reduces the half width of the spectral peaks, it increases the sensitivity toward detecting shoulders or second peaks that may not be apparent in the raw spectra (Fig. 1b). Thus, areas occupied by lymphocytes and macrophages can be easily distinguished providing a fast tissue screening method. Here, HCA was able to distinguish macrophages and lymphocytes based on the infrared response, even in areas where both occurred intermixed. (Fig. 1c) The tissue in direct proximity to cells had a slightly altered collagenous structure. Case 1 also exhibited multiple glassy, green particles which can typically observed around THRs that underwent taper corrosion (Fig. 2a). HCA image was able to visualize and distinguish large CrPO₄ particles, embedded within fibrin exudate rich areas, collagenous tissue without inflammatory cells, and a nearby area with a strong macrophage presence and some finer CrPO₄ particles (Fig. 2d). Moreover, this method can not only locate macrophages, but distinguish particle-laden macrophages depending the type of particles within the cells. In Case 2 (Fig. 3a), clustering results (Fig. 3 b&c) are consistent with the fact that different particle types are associated with MoM bearing surface wear (Co rich particles), corrosion of the CoCrMo taper junctions (Cr-oxides and –phosphate), fretting of Ti-alloy dual modular tapers (Ti-oxides, Ti alloy particles), and even suture debris, which all occurred in this case. Although details of debris types are not available, specifications are possible by coupling other techniques.

The results demonstrate that multivariate FTIRI based spectral histopathology is a powerful tool to characterize the chemical structure and foreign body response within periprosthetic tissue, thus providing insights into the biological impact of different types of implant debris.

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Little information is available regarding the demographic characteristics and outcomes of patients with periprosthetic joint infection (PJI) resulting from anaerobic organisms, especially in the knee joint.

We performed a retrospective cohort analysis of all cases of knee PJI that were treated at our institution during the period from 2005 through 2012.

Anaerobes were involved in 11 (13%) of 86 first-time episodes of knee PJI, and peptostreptococcus was the most commonly isolated pathogen (10 [91%] of the 11 episodes). The average age of patients was 70 years (range, 62 to 79) and women were more than men (7 vs. 4) to develop anaerobic PJI. Of the 11 episodes of anaerobic PJI, 8 (73%) were treated with 2-stage revision arthroplasty for chronic latent infection, and 3 (27%) with parenteral antibiotics for positive intraoperative culture. Those treating with 2-stage revision arthroplasty had average 21 months prosthetic age (range, 2 to 41), and 10 weeks interim period between stages (range, 7 to 14). The overall successful rate for treating anaerobic knee PJI was 90%, and 88% for chronic latent infection.

naerobic PJI represents a substantial proportion of all occurrences of knee PJI. Treating with resection of the prosthesis and subsequent reimplantation is associated with a favorable outcome for chronic latent infection.

Image-guided spine surgery requires registration between the patient anatomy and the preoperative computed tomography (CT) image. We have previously developed an accurate and robust registration technique for this application by using intraoperative ultrasound to acquire patient anatomy and then registering the ultrasound images to the CT images by aligning the posterior vertebral surfaces extracted from both modalities. In this study, we validate our registration technique across 18 vertebrae on three porcine cadavers.

We applied the ultrasound-registration technique on the thoracic and lumbar vertebrae of the porcine cadavers using both single sweeps and double orthogonal sweeps. For each sweep pattern at each vertebra, we also randomly simulated 100 different initial misalignments and registered each misalignment. The resulting registration transformations are compared to gold standard registrations to assess the accuracy and the robustness of the technique.

Orthogonal-sweep acquisition was found to be the sweep-pattern that performed the best and yielded a registration accuracy of 1.65 mm across all vertebrae on all porcine cadavers. It was found that the target registration errors (TRE) stay relatively constant with increasing initial misalignment and that the majority (82.7%) of the registrations resulted in TREs below the clinically recommended 2 mm threshold. In addition, it was found that the registration accuracy varies by the sweep pattern and the vertebral level, but neighbouring vertebrae tend to result in statistically similar accuracy.

We found that our ultrasound-CT registration technique yields clinically acceptable accuracy and robustness on multiple vertebrae across multiple porcine cadavers.

The lumbar or sacral root compression is frequently associated with degenerative spinal diseases. It may be caused by the hypertrophic facets, hypertrophic ligamentum flavum, or protruding disc. Canal stenosis, epidural hematoma, the cyst of pseudo-joint from degenerative or lytic-type spondylolisthesis, or tumors are less common. We present one unusual case with the severe progressive symptom of bilateral S2-4 root compression. The 80-year-old active male suffered the intermittent claudication for 4 months and got the worse symptom including bilateral painful buttocks in recent one month. The bilateral radiation pain cannot be changed at any position and taking a rest. Plain x-ray showed the degenerative spondylolisthesis over L4-5 level. The magnetic resonance imaging showed the cyst-like mass indented the dura posteriorly. During the operation, one huge psudo-joint capsule created from the interspinous ligament compressed the dorsal side of the cauda equina. We performed the posterior decompression and removal of the pseudo-joint capsule and ligamentum flavum with posterolateral fusion. The patient was completely resolved from all the symptoms after surgery. Therefore we present the unusual case and discuss the differentiation from synovial or ganglion cysts of the spine.

We aimed to find out whether the Hastings bipolar prosthesis moved in a bipolar fashion after its use for displaced fractures of the femoral neck. In 65 patients non-weight-bearing movement was assessed radiographically and compared with an earlier study of the Monk prosthesis. In 70% of patients, the only movement was between the acetabulum and the prosthetic shell, the prosthesis behaving as if it were unipolar. This did not change with time, but there was a slight improvement in the range of movement, particularly in flexion. The absence of movement between the outer shell and the metal head is most probably due to the design of the prosthesis and makes this prosthesis unsuitable for use in osteoarthritic hips.

A simple procedure of using a Smillie knife to release the lateral patellar retinaculum and the capsule in the unstable patella syndrome is described. The syndrome includes recurrent dislocation, recurrent subluxation and acute dislocation of the patella. Arthroscopy, to exclude any other pathology such as chondromalacia patellae, is performed before proceeding to closed lateral release. The results of this procedure are as good as those after more major surgical procedures. In a small percentage of patients a second operation such as tibial tubercle transfer or patellectomy may be necessary, especially in patients with an underlying congenital abnormality; but in many patients this type of major surgery has proved unnecessary.