The Reliability of a Scoring System for Corrosion and Fretting,and Its Relationship to Material Loss of Tapered,Modular Junctions of Retrieved Hip Implants

It has been suggested that corrosion and fretting at the tapered, modular junctions of hip arthroplasties may contribute to implant failure. In this study the reliability of a commonly used peer-reviewed scoring system for visual assessment of corrosion and fretting at these junctions was evaluated. Volumetric material loss at the tapered head surface was measured and associations with the visual scores were investigated. We found that the inter-observer reproducibility and single-observer repeatability of the corrosion scores were substantial using Cohen’s weighted Kappa statistic (k = 0.64–0.71). The reproducibility and repeatability of the fretting scores however were slight to fair (k = 0.18–0.31). Taper corrosion scores were significantly and moderately correlated with the volume of material loss measured (Spearman’s r = 0.59; P < 0.001). We recommend the continued use of this scoring system but it should not be a substitute for measurement of material loss.     

Can There be a Place for Intraoperative Salvaged Blood in Spine Tumor Surgery?

Background

Intraoperative cell salvage (IOCS) has been used in musculoskeletal surgery extensively. However, it has never found its place in musculoskeletal oncologic surgery. We have conducted the first-ever study to evaluate the feasibility of IOCS in combination with a leucocyte-depletion filter (LDF) in metastatic spine tumor surgery. This was to pave the path for use of IOCS-LDF in musculoskeletal oncologic surgery.

Methods

Patients with a known primary epithelial tumor, who were offered surgery for metastatic spinal disease, were recruited. Blood samples were collected at three different stages during the surgery: from the operative field before IOCS processing, after IOCS processing, and after IOCS-LDF processing. Three separate samples (5 mL each) were taken at each stage. Samples were examined using immunohistochemical monoclonal antibodies to identify tumor cells of epithelial origin.

Results

Of 30 patients in the study, 6 were excluded for not fulfilling the inclusion criteria, leaving 24 patients. Malignant tumor cells were detected in the samples from the operative field before IOCS processing in eight patients and in the samples from the transfusion bag after IOCS processing in three patients. No viable malignant cell was detectable in any of the blood samples after passage through both IOCS and LDF.

Conclusions

The findings support the notion that the IOCS-LDF combination works effectively in eliminating tumor cells from salvaged blood, so this technique can be applied successfully in spine tumor surgery. This concept can then further be extended to whole musculoskeletal tumor surgery and other oncologic surgeries with further appropriate clinical studies.