Association between hypoxemia and anemia following arthroplasty: A pilot clinical study.

Hypoxia and anemia are common complications following joint arthroplasty. Whether hypoxia indicates that a patient is anemic and whether anemia causes a decline in arterial oxygen pressure accompanied by hypoxemia are not completely understood. The aim of the present study was to determine the association between hypoxemia and anemia following arthroplasty. A total of 135 patients who underwent arthroplasty at the China-Japan Friendship Hospital between January and May 2013 were retrospectively analyzed. The patients were divided into five groups depending on the type of arthroplasty they had experienced: Unilateral total knee arthroplasty (TKA), bilateral TKA, unilateral total hip arthroplasty (THA), bilateral THA or unilateral unicompartmental knee arthroplasty. Perioperative peripheral oxygen saturation (SpO2) and hemoglobin (Hb) levels were assessed, and the associations between the changes in SpO2 (ΔSpO2) and hemoglobin (ΔHb) levels on the first and third postoperative days (PODs) were analyzed using Pearson's correlation test for each group. The perioperative SpO2 curves for the various groups were typically at their lowest on the day of surgery. Significant hypoxemia was observed on POD 0-2, although a stable recovery curve was observed on POD 3-5. Trends in ΔHb were observed among the 5 groups, with the lowest Hb value observed predominantly on POD 2 and 3. By POD 4 and 5 Hb levels had recovered, with a steadily and consistently increasing curve. There was no statistically significant correlation between ΔSpO2 and decrease in Hb levels (P>0.05). SpO2 levels should not serve as a clinical indicator of the incidence and severity of anemia in patients who have undergone primary arthroplasty. To a point, the degree of postoperative anemic status does not affect SpO2 levels.

Intractable bone marrow edema syndrome of the hip.

There is a need for an effective and noninvasive treatment for intractable bone marrow edema syndrome of the hip. Forty-six patients with intractable bone marrow edema syndrome of the hip were retrospectively studied to compare the short-term clinical effects of treatment with high-energy extracorporeal shock wave therapy vs femoral head core decompression. The postoperative visual analog scale score decreased significantly more in the extracorporeal shock wave therapy group compared with the femoral head core decompression group (P<.05). For unilateral lesions, postoperative Harris Hip Scores for all hips in the extracorporeal shock wave therapy group were more significantly improved than Harris Hip Scores for all hips in the femoral head core decompression group (P<.05). Patients who underwent extracorporeal shock wave therapy also resumed daily activities significantly earlier. Average overall operative time was similar in both groups. Symptoms disappeared significantly sooner in the extracorporeal shock wave therapy group in patients with both unilateral (P<.01) and bilateral lesions (P<.05). Hospital costs were significantly lower with extracorporeal shock wave therapy compared with femoral head core decompression. The intraoperative fluoroscopy radiation dose was lower in extracorporeal shock wave therapy than in femoral head core decompression for both unilateral (P<.05) and bilateral lesions (P<.01). On magnetic resonance imaging (MRI), bone marrow edema improved in all patients during the follow-up period. After extracorporeal shock wave therapy, all patients remained pain-free and had normal findings on posttreatment radiographs and MRI scans. Extracorporeal shock wave therapy appears to be a valid, reliable, and noninvasive tool for rapidly resolving intractable bone marrow edema syndrome of the hip, and it has a low complication rate and relatively low cost compared with other conservative and surgical treatment approaches.

Correlation between the coverage percentage of prosthesis and postoperative hidden blood loss in primary total knee arthroplasty.

BACKGROUND: The aim of this study was to determine the relationship between prosthesis coverage and postoperative hidden blood loss (HBL) in primary total knee arthroplasty (TKA). METHODS: A total of 120 patients who had undergone unilateral TKA from August 2012 to May 2013 were retrospectively studied. The Gross formula was used to calculate the amount of HBL. Routine standard anteroposterior (AP) and lateral X-ray films of the knee joint were taken postoperatively and used to measure the percentages of coronal femoral and of coronal and sagittal tibial prosthetic coverage. Then Pearson's correlation analysis was performed to assess the correlations between the percentages of prosthetic coverage for each AP and lateral position and HBL on the first and third postoperative days. RESULTS: The volumes of HBL on the first and third postoperative days after TKA were (786.5 ± 191.6) ml and (1 256.6 ± 205.1) ml, respectively, and lateral X-ray film measurements of percentages of coronal femoral, tibial coronal, and sagittal prosthetic coverage were (87.9 ± 2.5)%, (88.5 ± 2.2)%, and (89.1 ± 2.3)%, respectively. Pearson's correlation analysis showed statistically significant correlations between percentages of total knee prosthetic coverage for each AP and lateral position and volumes of HBL on the first and third postoperative days (P < 0.05). CONCLUSIONS: HBL after TKA correlates with degree of prosthetic coverage. To some extent, the size of the surfaces exposed by osteotomy determines the amount of HBL. Choice of the appropriate prosthesis can significantly reduce postoperative HBL. Designing individualized prostheses would be a worthwhile development in joint replacement surgery.