Diagnostic Accuracy of the Synovial Fluid α-Defensin Lateral Flow Test in Periprosthetic Joint Infection: A Meta-analysis.

OBJECTIVES: There is a controversy on the diagnostic reliability and accuracy of synovial fluid α-defensin in periprosthetic joint infection (PJI). We performed this meta-analysis to evaluate the diagnostic accuracy of the α-defensin lateral flow test in PJI. METHODS: PubMed, Embase, and the Cochrane library were systematically searched, and articles (up to January 2020) on the diagnosis of hip and knee PJIs using the α-defensin Synovasure lateral flow test were included. The diagnostic accuracy of the α-defensin lateral flow test in PJI was evaluated using meta-analysis. The pooled sensitivity, specificity, accuracy, positive and negative likelihood ratio, diagnostic odds ratio, and post-test probabilities were calculated. RESULTS: Seventeen studies including 1443 cases were included. Meta-analysis showed the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and a diagnostic odds ratio was 0.83 (95% CI 0.77, 0.88), 0.95 (95% CI 0.93, 0.97), 16.86 (95% CI 11.67, 24.37), 0.17 (95% CI 0.13, 0.24) and 85.30 (95% CI 47.76, 152.35), respectively. The area under the hierarchical summary receiver operating characteristic curve was 0.97 (95% CI 0.95, 0.98). Subgroup analysis also confirmed the high efficiency of α-defensin Synovasure lateral flow test in diagnosing PJIs, irrespective of ethnicity. Fagan's nomogram analysis there was a high positive post-test probability of 94% and a low negative post-test probability of 15%. CONCLUSIONS: We indicated that the α-defensin lateral flow test had a high accuracy for diagnosing PJI. Large-scale studies are needed to validate its significance in PJI diagnosis.

[Advances on treatment of periprosthetic infection and antibiotic delivery system after total hip arthroplasty].

Periprosthetic infection after hip replacement is a clinical catastrophic disease, which often leads to the failure of the prosthesis. It needs the combination of systemic antibiotics to cure the infection, which brings huge burden to doctors and patients. There are strict indications for debridement and one-stage revision of the prosthesis, and few cases meet the requirements. The second revision is still the gold standard for the treatment of periprosthetic infection. It is suitable for all infection conditions and has a high success rate. On the second phase of renovation, the antibiotic sustained release system plays a key role, and the carrier of antibiotic sustained-release system is the focus of current research, including classic bone cement and absorbable biomaterials. Bone cement has strong mechanical strength, but the antibiotic release shows a sharp decline trend; the absorbable biomaterials can continuously release antibiotics with high concentration, but the mechanical strength is poor, so it could not use alone. The combination of bone cement and absorbable biomaterials will be an ideal antibiotic carrier. PMMA is the most commonly used antibiotic carrier, but the antibiotic release concentration is decreased sharply after 24 hours. It will be difficult to control the infection and increase the risk of bacterial resistance if it is lower than the minimum inhibitory concentration. The biodegradable materials can release antibiotics completely, with long release time and high concentration, but low mechanical strength. Antibiotic spacer plays an important role in the control of infection. In the future, how to further extend the antibiotic release time of antibiotic sustained-release system, increase the amount of antibiotic release and maintain the mechanical strength of the material will be studied.

[Procalcitonin as a sensitive index of chronic infection after artificial joint replacement:a retrospective analysis].

OBJECTIVE: To study the predictive value of procalcitonin as a serum biomarker in diagnosis of late periprosthetic joint infection(PJI) for providing theoretical reference basis for diagnosis of PJI. METHODS: A total of 77 cases were retrospective included from January 2015 to December 2017 for revision of total hip arthroplasty and total knee arthroplasty, according to the diagnostic criteria of Musculoskeletal Infection Society(MISI). All cases were divided into infection group and non-infection group. Infection group included 21 cases, 7 cases for male and 14 cases for female, with an average age of (60.70±8.75) years old (ranged 43 to 75 years old). Non-infection group 56 included cases, 24 cases for male and 32 cases for female, with an average age (64.40±12.14) years old (ranged 43 to 85 years old). Concentration of preoperative serum procalcitonin was examined and the chi-square test was used to compare positive rate between the two groups. RESULTS: Two cases in the infection group had positive serum procalcitonin, 0.06 ng/L and 0.10 ng/L respectively, with the positive rate of 9.52%; 4 cases in non-infected group had positive serum procalcitonin, 0.05 ng/L, 0.06 ng/L, 0.06 ng/L, 0.16 ng/L respectively, with the positive rate of 7.14%. No statistically significant difference was observed between the two groups (P=0.662). CONCLUSIONS: Most of PJI were low toxicity infection with little systemic inflammatory response, so the concentration of serum procalcitonin was normal or slightly higher level, had little clinical significance for diagnosis of PJI. But the cases of this retrospective study are not enough, more cases are needed for further study.

Pigmented villonodular synovitis: a retrospective multicenter study of 237 cases.

PURPOSE: To review clinical characteristics of pigmented villonodular synovitis (PVNS) in China. METHODS: Electronic medical records (EMR) of four Chinese institutes were queried for patients with histologically proven PVNS between January 2005 and February 2014. Their data were collected including gender, age at diagnosis, clinical presentation, affected site, symptom duration, comorbidities, treatment strategy, recurrence and routine laboratories. RESULTS: A total of 237 patients with biopsy-proven PVNS were investigated. The gender ratio was 1.35 for a female predominance (101 males and 136 females). The average age was 36 years (range, 2 to 83 years). The median delay from initial clinical symptom to diagnosis was 18 months. Main affected areas were the knee (73.84%) and the hip (18.14%). Forty patients had a clear history of joint trauma. Six patients were concurrently diagnosed with PVNS and avascular necrosis (AVN). Five patients suffered from PVNS following implantation of orthopaedic devices including artificial prosthesis, plate and wire. One hundred and twenty-nine patients underwent arthroscopic synovectomy and 108 open synovectomy. Altogether 48 patients (26 males and 22 females) had recurrence of disease. The relapse rate was 24% (knee) and 6.98% (hip), 20.93% (open surgery) and 19.44% (arthroscopy), respectively. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) rate were elevated in 45.83% and 38.41% of the patients respectively. CONCLUSIONS: To our knowledge, this study is the largest sample size of PVNS patients reported as well as the largest sample of PVNS with concurrent AVN reported to date. Our outcomes suggest that PVNS shows a female predominance, occurs mostly between 20-40 years and favors the knee and hip. Recurrence is frequent, particularly in the knee. Serum ESR and CRP may be elevated in some patients. Additionally, the present study supports the theory of an association between PVNS and orthopedic surgery, which is not limited to joint replacement.

Vascularised greater trochanter bone graft, combined free iliac flap and impaction bone grafting for osteonecrosis of the femoral head.

PURPOSE: To investigate the curative efficacy of osteonecrosis of the femoral head (ONFH) in a hip-preserving operative approach, by grafting a vascularized greater trochanter flap combined with a free iliac flap, in an attempt to seek an innovative approach for patients who suffered middle to late stage ONFH without total hip arthroplasty (THA) surgery. METHOD: Our research included a total of 60 patients (66 hips) who accepted hip-preserving surgery by grafting a vascularized greater trochanter flap combined with a free iliac flap which was tightly filled by hammering because of ONFH (most were Association Research Circulation Osseous (ARCO) stage III patients) from January, 2006 to December, 2010. A Harris Hip Score was obtained during follow-ups, evaluating the clinical efficacy, X-rays were taken regularly for image assessing, and the SF-36 scale was used for estimating quality of life. Terminal observation time was considered when patients had symptom-dependant indications for performing another hip-preserving surgery or THA surgery. RESULTS: Fifty-eight patients (64 hips) were eventually contacted by telephone for an out-patient clinic return visit, with a mean follow-up time of 35.8 months (varied from 12 months to 60 months), but two patients lost contact for various reasons. The demographic data were as follows: there were 16 ARCO IIIA cases, 22 ARCO IIIB cases, and 26 ARCO IIIC cases, respectively. Postoperative X-rays revealed a well-repaired necrotic area of the femoral head and improvement of femoral-acetabulum coverage. The last follow-up mean Harris Hip Score was 86.56 ± 7.38 (excellent results reached 87.50%), which were greatly improved compared to 50.95 ± 6.86 pre-operatively. Also the postoperative mean scores of all dimensions of the SF-36 scale were improved to some extent. Additionally the physical component summary (PSC) scores were enhanced from 42 ± 13 pre-operatively to 78 ± 11, while the postoperative mental component summary (MCS) scores (76 ± 11) largely increased in contrast to pre-operative scores (51 ± 10), with both target indices having statistical significance (p = 0.005, p = 0.01), signifying hugely improvement of the quality of life of the patients. A correlation was found between Harris Hip Score and all dimensions of SF-36 scale (r = 0.32-0.72), especially closely correlated with physical functioning (PF), role-physical (RP) and bodily pain (BP) in PCS aspect (r = 0.72, p < 0.01; r = 0.58, p < 0.01; r = 0.65, p < 0.01, respectively). CONCLUSION: There is definite curative efficacy for the treatment of ONFH with an hip-preserving operative approach by grafting a vascularized greater trochanter flap combined with a free iliac flap which was tightly filled by hammering. This kind of operative approach reconstructs the biological stability of femoral head, which promotes repair of necrotic areas and indirectly preserves the femoral head of patients and a majority of hip function. It possesses vast clinical as well as practical significance, because the long-term efficacy can satisfy fundamental life requirements, especially for those young and middle-aged patients who suffer ONFH to avoid or put off the time of total hip arthroplasty (THA) surgery.

[Experimental study of directional differentiation of bone mesenchymal stem cells (BMSCs) to osteoblasts guided by serum containing cistanche deserticola].

OBJECTIVE: To study directional differentiation of BMSCs guided by Desert living Cistanche (Herba Cistanches) which invigorates the kidney. METHODS: Primary BMSCs were obtained by whole bone marrow culture and subcultured to the fourth generation by trypsin digestion, and than inoculated into two six-well plates at 5 x 10(6) cells per milliliter, all the plates were divided into three groups as blank group, Dexamethasone (DXM) group and Herba Cistanches group, three wells in each group, medium were changed at day 2. The blank group were changed with L-DMEM containing 10% FBS. The DXM group were changed with medium containing 10 mmol/L beta-sodium glycerophosphate, 0.1 micromol/L DXM and 50 mg/L vitamin C. The Herba Cistanches group were changed with medium containing 10% blood serum containing Herba Cistanches and L-DMEM. One of the six-well plates was stained by alkaline phosphatase (AKP) at the tenth day,the other one was stained by alizarin Bordeaux at the twentieth day. RESULTS: At the tenth day DXM group and Herba Cistanches group were ALKP stained positive; from the 12th day,white calcium nodus could be seen at the surface of the wells; which alizarin stained positive by the twentyth day. CONCLUSION: The medium containing Herba Cistanches can guide BMSCs to differentiate into osteoblast, which promises a favorable prospect for the treatment of osteoporosis and bone fracture disunion.