[The effect of visualized saphenous nerve block through minimally invasive far medial-subvastus approach on the analgesia after total knee arthroplasty].

Objective: To report a method of visualized saphenous nerve block (VSNB) through minimally invasive far medial-subvastus approach distal to the adductor canal in total knee arthroplasty (TKA), and investigate the effect of VSNB in this way on postoperative pain relief. Methods: A total of 100 patients with knee osteoarthritis were prospectively included from June 2018 to October 2019, 29 males and 71 females, aged 50-87(70±8) years. All patients undergoing TKA through minimally invasive far medial-subvastus approach were randomized to visualized saphenous nerve block combined with periarticular infiltration analgesia group (Group VSNB+PIA) or only periarticular infiltration analgesia group (Group PIA),50 cases in each group. The visual analogue scale (VAS) was used to evaluate the pain degree of patients. Furthermore, the scores of VAS in resting and active state at 4, 8, 12, 24, 48, 72 hours after operation and the proportion of patients receiving parecoxib within 72 hours after operation were compared between the two groups. Results: There was statistically significant difference between the two groups in terms of VAS scores in resting state after surgery(F=15.295,P<0.05).The postoperative VAS scores of Group VSNB+PIA at 4, 8, 12, 24 hours at resting state were 1.3±0.8, 1.4±0.7, 1.7±0.8, 3.1±0.8 respectively, which were all significantly lower than those of Group PIA (1.6±0.9, 1.8±0.8, 2.3±0.9, 3.6±0.8) (P<0.05). The overall difference in terms of VAS scores at active state after surgery was statistically significant between the two groups(F=18.532, P<0.05). The postoperative VAS scores of Group VSNB+PIA at 4, 8, 12, 24 hours at active state were 2.0±0.8, 2.2±0.7, 2.7±0.6, 3.7±0.7 respectively, which were all significantly lower than those of Group PIA (2.3±0.8, 2.7±0.7, 3.3±0.8, 4.4±0.7)(P<0.05). Fourteen percent of patients (7/50) in VSNB+PIA group accepted parecoxib within 72 hours after surgery, which was significantly lower than that in PIA group (34%, 17/50) (P<0.05). Conclusions: It is easy to expose the saphenous nerve beyond the adductor canal through minimally invasive far medial-subvastus approach. The Combination therapy of VSNB+PIA is more effective than the simple per-articular infiltration analgesia in providing pain relief after total knee arthroplasty.

[Short-term efficacy of endoscope assisted arthroplasty for total hip replacement via a minimum invasive direct anterior approach].

Objective: To present the surgical technique of endoscope assisted arthroplasty for total hip replacement via minimum invasive direct anterior approach and analyze its early clinical outcome. Methods: From November 2019 to May 2020, endoscopic total hip arthroplasty via direct anterior approach was performed on 30 patients (32 hips), including 12 males (13 hips) and 18 females (19hips), in the Department of Orthopedics of Fujian Provincial Hospital. The average age of patients was (63±14) years (ranged 32-87 years). The average body mass index (BMI) of the patients was (26.9±4.5) kg/m2. There were 12 cases whose BMI was higher than 28.0 kg/m2 and the maximum BMI was 35.2 kg/m2. The surgery was performed on supine position using a 5-6 cm proximal transverse incision and a distal selective percutaneous puncture incision to perform the acetabulum preparation and the prosthesis implantation with the novel designed split tool under the monitoring of endoscope; the lift-top tractor system was used to raise the femur in the transverse incision for femoral side preparation and prosthesis implantation. Relevant data such as the perioperative status, operation time, postoperative pain score assessed with visual analogue score (VAS), prosthesis position, joint function, lateral femoral cutaneous nerve function and patient satisfaction were recorded to analyze the short-term efficacy. Results: The average length of incision of the 30 cases(32 hips)was (5.9±0.4) cm. All patients in this study had I/A wound healing with no perioperative complications such as infection, poor wound healing and fractures of the proximal femur. The average operation time was (65±14) min, and the average amount of blood loss was (136±56) ml. The average acetabular abduction angle and acetabular antegrade inclinations was 41.4°±3.6° and 16.0°±5.3°, respectively. The resting-state VAS of pain at 6 h and 24 h after operation were all ≤2, and there was no significant difference between the VAS scores after exercise and the VAS scores at the resting state (both P>0.05). There was no statistically significant difference between the VAS scores at the same state at different times (both>0.05). The weight-bearing exercise was applied in all patients within 12 h after surgery. The length of postoperative hospital stays varied from 1 to 3 days((2.0±0.9) days). At the 6th-month follow-up, the Harris score of the hip was 94.7±3.0, which significantly improved when compared with that before the operation (35.5±8.1)(P<0.01). No sensory abnormalities were observed. The satisfaction score of the patients was 9.3±0.5 (full score set to 10). Conclusions: The efficacy and safety of the endoscope assisted total hip arthroplasty for total hip replacement is acceptable. This procedure can help to reduce the compression of the muscles by the retractor in the conventional operation. It can be applied to obese and muscular patients.

[Common peroneal nerve "pre-release" to avoid nerve palsy in total knee arthroplasty for severe valgus deformities].

Objective: To investigate the clinical efficacy of common peroneal nerve "pre-release" to avoid nerve palsy in total knee arthroplasty for severe valgus deformities. Methods: Twenty patients (22 knees) with severe valgus deformities were prospectively and continuously included in Fujian Province Hospital from January 2010 to January 2016. Medial parapatellar arthrotomy, femoral distal resection using the intramedullary cutting guide with 3° to 5° of valgus and the common peroneal nerve "pre-release" was performed, the patella was routinely resurfaced. A common peroneal nerve checking was performed (LSUHSC system), then, these outcomes were collected independently using visual analogue scale (VAS) of pain, Knee Society Score (KSS), Hospital for Special Surgery Knee Score (HSS), range of motion of knees (ROM), femorotibial angle (FTA), hip-knee-ankle angle (HKA), condylar-hip angle (CHA), plateau- ankle angle (PAA). The paired t test was used to compare the data before and after the operation. Results: Patients were followed up for 18 to 55 (mean, (38±8) months). According to Krackow's classification, all cases were typed Ⅱ. All the patients had a completely normal motor (grade 5) and sensory (LSUHSC score was 5) nerve function of common peroneal nerve postoperatively. No decrease or loss in muscle strength and cutaneous sensation associated with common peroneal nerve was found. The VAS of pain, KSS, HSS, ROM, HKA, CHA, and PAA were all improved after the operation when compared with those before the operation (t=21.602, -70.238, -82.455, -20.560, 16.058, 9.682, 3.439, all P<0.05). The alignment of lower limbs was corrected basically, and the FTA decreased from 31.7°±8.0° before operation to 5.0°±2.0° at the last follow-up, the differences was statistically significant (t=16.725, P<0.05). No common peroneal nerve palsy and transient or late-onset palsy occurred, and no revision was needed for instability during the follow-up in all the patients. Conclusion: Common peroneal nerve "pre-release" for severe valgus knees may be an effective method in protecting the nerve.

[Comparison of the effects of total hip arthroplasty via direct anterior approach and posterolateral piriformis-sparing approach].

OBJECTIVE: To compare the clinical effects of direct anterior approach (DAA) and posterolateral piriformis-sparing approach (Mis-PLA) for minimally invasive surgery of total hip arthroplasty. METHODS: The patients who had total hip arthroplasty from March 2015 to February 2016 were randomly divided into 2 groups: DAA group and Mis-PLA group. In the study, 43 patients (45 hips) were performed with total hip replacement via the direct anterior approach (DAA group). As comparison, 39 patients (42 hips) were performed with total hip replacement via the posterolateral piriformis-sparing approach (Mis-PLA group) at the same period. DAA group: 27 male patients (27 hips), and 16 female patients (18 hips), with an average age of (57.4±7.3) years, preoperative Harris score (41.4±8.7), body mass index (BMI) (24.3±2.2) kg/m2; Mis-PLA group: 25 male patients (26 hips), 14 female patients (16 hips), with an average age of (59.2±7.3) years, preoperative Harris score (39.6±8.4), BMI (24.7±2.5) kg/m2. The length of incision, operation time, blood loss, postoperative Harris score were observed and specially the hip functional recovery was fully assessed. RESULTS: (1) All the incisions healed by first intention. No complications were found in both groups. The length of incision:DAA group: (9.2±0.7) cm and Mis-PLA group: (9.5±0.6) cm. No statistical significant differences were found (P=0.053). The operation time:DAA group (74.3±10.1) min and Mis-PLA group (37.5±4.3) min, which showed statistically significant differences (P<0.01). Blood loss: DAA group (229.6±79.2) mL and Mis-PLA group (215.7±56.0) mL. No statistical significant differences were found (P=0.366). (2) The patients in both groups were followed up for 6-12 months. The Harris hip scores for 6 weeks' follow-up: (85.5±4.1) in DAA group and (79.0±4.4) in Mis-PLA group, which indicated statistically significant differences (P<0.01). The Harris scores for the 6-month follow-up: (94.3±2.7) in DAA group and (95.2±1.9) in Mis-PLA group. No statistically significant differences were found (P=0.125). The basic daily hip function analysis for the 6-week follow-up: walking speed: no statistically significant differences were found between the two groups (P=0.298); Climbing stairs: Mis-PLA group' outcome was better than DAA group's with statistical differences (P=0.047); Circling, sitting and wearing shoes and socks: outcomes in DAA group exceeded Mis-PLA group's with statistically significant differences (P<0.01, P=0.016, P<0.01). CONCLUSION: Total hip arthroplasty through either DAA or Mis-PLA approaches could result in very satisfactory clinical effect. Comparing with DAA, Mis-PLA requires less operation time, shorter learning curve,which indicates that it is a relatively safer approach. The advantages of total hip arthroplasty through direct anterior approach lie in less positional limitation in the early stage of postoperative period, as well as a faster recovery of hip function.

Tea polyphenols as inhibitors of mutagenicity of major classes of carcinogens.

Previous research suggested that the mutagenicity of some genotoxic carcinogens, mainly heterocyclic amines, was decreased by green or black tea extracts, or tea polyphenol fractions. Thus, it seemed important to test a variety of genotoxic carcinogens with distinct chemical structures and means of biochemical activation as regards modification of mutagenicity in appropriate strains of Salmonella typhimurium by 3 concentrations of polyphenols 60, 100, or B, standard commercial polyphenol preparations from green or black tea. Polyphenols sharply decreased the mutagenicity of a number of aryl- and heterocyclic amines, of aflatoxin B1, benzo[a]pyrene, 1,2-dibromoethane, and more selectively, of 2-nitropropane, all involving an induced rat liver S9 fraction. Good inhibition was found with 2 nitrosamines that required a hamster S9 fraction for biochemical activation. No effect was found with 1-nitropyrene, and with the direct-acting (no S9) 2-chloro-4-methyl-thiobutanoic acid. Thus, with some exceptions, polyphenols considerably decreased the mutagenicity of diverse types of carcinogens.

[Effect of copper and zinc on the metabolism of N-nitrosamine and the activity of cytochrome P-450 in the liver of rats].

The effect of copper and zinc on the metabolism of N-nitrosamine and activity of cytochrome P-450 in the liver of rats was studied. Copper and zinc enhanced obviously the activity of cytochrome P-450 in the liver. The level of cytochrome P-450 in the liver of control rats was 0.64 nmol/mg protein but that in the liver of rats treated with copper or zinc was 1.31 and 1.17 nmol/mg protein. There was a significant difference between the two groups (P less than 0.01-0.001). The activity of demethylase reflected the metabolic level of N-nitrosamine. In the control group, metabolic level of N-dimethyl-nitrosamine, N-methyl-N-butylacetonylnitrosamine and nitrosopyrrolidine was markedly higher than the copper and zinc groups. It is indicated that copper and zinc inhibit obviously the activity of demethylase, resulting in reduction of the metabolic activation of N-dimethylnitrosamine, N-methyl-N-butylacetonylnitrosamine and nitrosopyrrolidine. The role of copper and zinc in the chemical carcinogenesis is discussed.

[O6-methyldeoxyguanosine in DNA of the adjacent epithelium in human esophageal cancer in Linxian County].

Radioimmunoassay of monoclonal antibodies against O6-methyldeoxyguanosine (O6-MedG) was used to detect the presence of these DNA adducts in the human esophageal epithelium. The analysis comprised 48 adjacent epithelial specimens of the esophageal and cardiac cancer resected in Linxian County and 30 specimens of the fetal esophageal epithelium and 4 of the normal esophageal epithelium from autopsy as collected from the hospital in Beijing. The results show that O6-MedG was detected in all the specimens from the esophageal and cardiac cancer patients. In 7 samples in the adjacent epithelium of esophageal cancer, the level of O6-MedG ranged from 0.5 to 1.0 pmol/mgDNA. 19 showed higher levels up to 37.4 pmol/mgDNA with a mean of 4.72 +/- 6.08 pmol/mgDNA. 5 samples of gastric mucosa showed the level of O6-MedG ranging 0.3-1.0 pmol/mgDNA and the remaining 6 showed a higher level of 1.2-13.4 pmol/mgDNA. The mean was 3.31 +/- 3.97. In all the 11 patients, O6-MedG was detected in the para-cancerous gastric mucosa of the cardiac cancer. 4 normal autopsied esophageal epithelial samples were too low for detection. Samples from the fetal esophageal epithelium showed lower level of O6-MedG, the mean was 0.4 +/- 0.57 pmol/mgDNA. The results mentioned above give us the new evidence that the effect of N-nitrosamines is most likely a causative factor in the carcinogenesis of human esophageal cancer.

Sampling method as a key factor in identifying K-ras oncogene mutations in preneoplastic colorectal lesions.

The development of sensitive polymerase chain reaction (PCR)-based techniques in recent years has enabled us to verify the possible presence of mutated oncogenes and tumor suppressor genes in stages preceding tumor formation. Early detection of mutants serves as a powerful tool for detecting exposure to carcinogens and can assist in diagnosis. In studies performed in the past few years, we have identified mutant ras alleles in preneoplastic samples of patients with and without colorectal cancer. Our studies have shown (i) that mutant ras alleles are present at low incidence in normal appearing tissues of patients with colorectal cancer. Such mutations are also found in colonic effluents of patients at risk for developing this tumor type; and (ii) that the method of sampling is critical to ensure true representation of the entire colonic mucosa. The implications of identifying ras mutations in patients without evidence for neoplasma are discussed.

Diethylnitrosamine exposure-responses for DNA ethylation, hepatocellular proliferation, and initiation of carcinogenesis in rat liver display non-linearities and thresholds.

In previous exposure-response studies, we have documented non-linearities for some of the early effects in rat liver of diethylnitrosamine (DEN) and a near no-effect levels for initiation of promotable liver neoplasms at the lowest cumulative exposure of 0. 5 mmol/kg body weight; this in spite of formation of DNA adducts and induction of hepatocellular altered foci (HAF). To extend these investigations, in an initiation segment, young male F344 rats were administered four exposures of DEN ranging from a cumulative total of 0.25 mmol, which is half of the previously used low exposure, up to 2 mmol per kg body weight, an effective initiating exposure. These exposures were achieved by once weekly intragastric instillations of one-tenth the total exposures for up to 10 weeks. The initiation segment was followed by a 4 week recovery segment, to allow for remission of acute and subchronic effects of DEN, after which the groups were maintained on 0.06% phenobarbital in the diet for 24 weeks to promote liver tumor development in order to assess initiation. During and after initiation and at the end of recovery, selected groups were studied for several crucial effects involved in hepatocarcinogenicity. The low exposure produced a low-level of DNA ethylation at both 5 and 10 weeks of exposure, measured as O(4)-ethylthymidine, the most persistent promutagenic ethylation product. At the 5 week interval, the adduct values of the higher exposures were less than proportional to the increment of exposure, suggestive of nonlinearity. Assessment of cellular proliferation by staining for proliferating cell nuclear antigen revealed that the lowest exposure did not increase the replicating fraction of hepatocytes during the initiation (10 weeks) or recovery (4 weeks) segments, whereas in the three higher exposure groups, proliferation was increased in relation to dose and time. Preneoplastic HAF expressing glutathione S-transferase-placental-type were present at low multiplicity in control livers and their multiplicity was increased in all exposure groups by the end of exposure, at which time the increase in the high exposure group was disproportionately greater than the increment of exposure. After phenobarbital administration in the promotion segment, all exposure groups exhibited further HAF increases at 39 weeks. At the end of the promotion segment, no hepatocellular neoplasm was found in 80 controls or in 40 rats in the low exposure group. In the mid-low exposure group, which was the previously studied low exposure, only one adenoma was found, yielding a 3% incidence, while in the two higher exposure groups, 32 and 80% of rats exhibited liver neoplasms, which were increased disproportionately greater than the increments of exposure. Thus, the findings document non-linearities of early DEN effects and at the lowest cumulative dose, a no-effect level (NEL) or threshold for initiation of promotable liver neoplasms. These findings provide a conceptual basis for understanding why low-level exposures to DNA-reactive carcinogens may convey no cancer risk.