Hydrolysis of Carbonates,Thiocarbonates, Carbamates,and Carboxylic Esters of α-Naphthol, β-Naphthol,and p-Nitrophenol by Human,Rat, and Mouse Liver Carboxylesterases

Thirty carbonates, thiocarbonates, carbamates, and carboxylic esters of -naphthol, -naphthol, and p-nitrophenol were synthesized and tested as substrates for liver carboxylesterases from the crude microsomal fractions of human and mouse, and purified isozymes, hydrolases A and B, from rat liver microsomes. The carbonates, thiocarbonates, and carboxylic esters of -naphthol were cleaved more rapidly than the corresponding -naphthol isomers by the mammalian liver esterases. -Naphthyl esters of acetic, propionic, and butyric acids were among the best substrates tested for these enzymes. The majority of the substrates was consistently hydrolyzed at higher rates by hydrolase B compared with hydrolase A, although the Michaelis–Menten constant (K _m) values of selected substrates differed widely with these two isozymes. Malathion was a 15-fold better substrate for hydrolase B than for hydrolase A. Compared with the corresponding carboxylates, the carbonate moiety of - and -naphthol and p-nitrophenol lowered the specific activities of the enzymes by about fivefold but improved stability under basic conditions. The optimum pH of mouse liver esterase with the acetate, methylcarbonate, and ethylthiocarbonate of -naphthol was between pH 7.0 and pH 7.6. Human and mouse liver microsomal esterase activities were about five orders of magnitude lower than the esterase activities of purified rat liver hydrolase B. A relationship between the catalytic activity of the enzymes and the lipophilicity of the naphthyl substrates indicated that (i) in the - and -naphthyl carbonate series, an inverse relationship between enzyme activity and lipophilicity of the substrates was observed, whereas (ii) in the -naphthyl carboxylate series, an increase in enzyme activity with increasing lipophilicity of the substrates up to a log P value of about 4.0 was observed, after which the enzyme activity decreased.     

Hyperostosis around the bilateral acetabulum associated with hypoparathyroidism

We report the case of a 57-year-old woman with hyperostosis around the bilateral acetabulum associated with untreated secondary hypoparathyroidism. She presented with gait disturbance and inability to walk. Radiographs showed abnormal ossification around her hips. We resected the ossifications to improve joint function. One year after surgery, radiographs showed no recurrence of ossification. When radiographs show excessive hyperostosis, it is important to exclude presence of metabolic bone disease.     

Using intraoperative radiography to detect incomplete seating of Trident acetabular system ceramic liners

Purpose

There have been some reports of incomplete seating of the ceramic liner in the Stryker Trident acetabular system. We sought to prevent incomplete seating through the use of intraoperative radiography.

Method

We retrospectively reviewed 21 hips in 18 patients who had undergone total hip arthroplasty using a posterolateral approach with a Stryker Trident ceramic liner. All procedures included an intraoperative anteroposterior view radiograph to evaluate liner seating. If incomplete seating was recognized we reinserted the liner. We investigated whether this technique made it possible to detect and correct incomplete seating.

Results

Six of the 21 hips evidenced incomplete seating. In four of these hips, the incomplete seating was revealed on the intraoperative radiograph: two were reinserted properly, one was replaced with a polyethylene liner, and in the last one the incomplete seating was missed despite the radiographical evidence. The location of the gap between the socket and liner caused by the incomplete seating was inferior in all these cases. Intraoperative radiography did not indicate incomplete seating in two hips in which the location of the gap was anterior; the problem was revealed by postoperative lateral view radiography.

Conclusion

With a posterolateral approach in a lateral decubitus position, the use of intraoperative radiography was effective when the gaps were superior or inferior. However, this approach made it easy to miss anterior gaps and intraoperative radiography did not reveal them.     

Readmission Following Laparoscopic Sleeve Gastrectomy

Methods:Data on 343 consecutive LSG operations performed from February 2010 to May 2014 by a single surgeon (PG) were analyzed. Patients readmitted within 30 d were compared to the remaining patients by using Student''s t test for continuous variables and the χ² test for categorical variables.Results:All LSGs were completed laparoscopically with no conversions to open procedures. There were no reoperations, leaks, perioperative hemorrhages, or mortalities. Twelve patients (3.5%) were readmitted; 1 was readmitted twice. There were no identified risk factors for readmission, including patient demographics, comorbidities, and perioperative factors. Notably, 7 (7%) readmissions occurred in the initial 100 patients and 5 (2%) in the remaining 243 patients (P = .04). Clinical pathways were modified after the initial 100 patients; routine contrast esophagograms were no longer performed, and a 1-day routine postoperative stay was adopted. Operative time also decreased from 94.2 ± 23.8 to 78.2 ± 20.0 min (P < .001).Conclusions:Readmission rates after LSG remain in a range similar to those described for other laparoscopic bariatric procedures. Larger prospective studies are needed to identify patterns of complications and readmissions in patients undergoing LSG that may differ from other bariatric procedures.     

Three-dimensional kinetic simulation before and after rotational acetabular osteotomy

Background

Some reports indicate that one of major causes of clinical failure after periacetabular osteotomy is development of secondary femoroacetabular impingement (FAI). To assess the impact of range of motion (ROM) on the increase in FAI following rotational acetabular osteotomy (RAO), we performed FAI simulations before and after RAO.

Methods

We evaluated 12 hips that had undergone RAO (study group), and 12 normal hips (control group). The study group was evaluated before and after surgery. Morphological parameters were evaluated to assess acetabular coverage. The acetabular anteversion angle, anterior CE angle, alpha angle, and combined anteversion angle were also measured. Impingement simulations were performed using 3D-CT. The ROM which causes bone-to-bone impingement was evaluated in flexion (flex), abduction, external rotation at 0° flexion, and internal rotation at 90° flexion. The lesions caused by impingement were evaluated.

Results

Radiographic measurements indicated improved postoperative acetabular coverage in the study group. The crossover sign was recognized pre- and postoperatively in every case in the study group and in no cases in the control group. In the simulation study, flexion, abduction, and internal rotation at 90° flexion decreased postoperatively. Impingement occurred within 45° internal rotation at 90° flexion in two preoperative and nine postoperative cases. The impingement lesions were anterosuperior of the acetabulum in all cases. There were correlations between anterior CE angle, CE angle, acetabular anteversion angle, and hip flexion angle. There were also correlations between the anterior CE angle, combined anteversion angle, and angle of internal rotation at 90° flexion.

Conclusions

In the postoperative simulation, there was a tendency to reduce the ROM in flexion, abduction, and internal rotation at 90° flexion due to impingement. Since there were more cases which caused impingement within 45° internal rotation at 90° flexion after RAO, we consider there is a potential for increased FAI after RAO.     

Accurate Leg Length Measurement in Total Hip Arthroplasty: A Comparison of Computer Navigation and a Simple Manual Measurement Device

Background

Several studies have shown that better placement of the acetabular cup and femoral stem can be achieved in total hip arthroplasty (THA) by using the computer navigation system rather than the free-hand alignment methods. However, there have been no comparisons of the relevant clinical advantages in using the computer navigation as opposed to the manual intraoperative measurement devices. The purpose of this study is to determine whether the use of computer navigation can improve postoperative leg length discrepancy (LLD) compared to the use of the measurement device.

Methods

We performed a retrospective study comparing 30 computer-assisted THAs with 40 THAs performed using a simple manual measurement device.

Results

The postoperative LLD was 3.0 mm (range, 0 to 8 mm) in the computer-assisted group and 2.9 mm (range, 0 to 10 mm) in the device group. Statistically significant difference was not seen between the two groups.

Conclusions

The results showed good equalization of the leg lengths using both computed tomography-based navigation and the simple manual measurement device.     

Do we need intraoperative radiographs for positioning the femoral component in total hip arthroplasty?

Introduction

Poor long-term results of total hip arthroplasty (THA) can result from femoral component misalignment. There are few reports that discuss the effectiveness of intraoperative radiographs for placing femoral components. This study is a retrospective review to find out the usefulness of intraoperative radiographs in detecting and improving the femoral component misalignment in posterior-approached primary THA.

Materials and methods

The study group included 150 primary THAs performed between September 2009 and April 2012. After the trial component insertion in lateral decubitus position, intraoperative radiography was performed. The surgeon assessed the femoral component position in three aspects: alignment, leg length, and offset. If it is not following the preoperative template, the surgeon makes the intraoperative adjustments to change the femoral component position. After the operation, postoperative radiograph was taken; the same parameters were measured and were compared to intraoperative findings. The changes in each parameter were classified into three categories: satisfactory, no change, and unsatisfactory. Among the three parameters, if one is satisfactory and the others are not unsatisfactory, we defined it as accurate positioning of the femoral component.

Results

Intraoperative adjustments were made in 122 cases (81.3 %). The adjustments included changes in the component size (35.3 %), component alignment (38.6 %), femoral offset (14.0 %), and additional femoral neck cuts (56.0 %). As a result, accurate positioning was successfully achieved in 112 cases (91.8 %) by taking intraoperative radiographs.

Conclusion

Our data suggest that intraoperative radiography is a useful method for detecting the errors of placing the femoral components, and the success of a surgeon to correct those errors after detecting them intraoperatively.