Bone marrow edema in the acromioclavicular joint after arthroscopic rotator cuff repair

BACKGROUND

Bone marrow edema (BME) in the acromioclavicular joint (ACj) may occur after arthroscopic rotator cuff repair (ARCR), resulting in persistent postoperative ACj pain. We investigated the incidence and clinical characteristics of BME in ACj after ARCR.

METHODS

Patients exhibiting ACj-related symptoms prior to ARCR surgery, no BME in the ACj on MRI, and an ability to undergo 2-year postoperative physical and MRI examinations of the ACj were included. Patients who underwent distal clavicle resection or osteophyte resection below the ACj and those unable to achieve primary repair of the rotator cuff were excluded. MRI evaluation was performed preoperatively and at 3, 6, 12, and 24 months postoperatively. Patients who showed BME in ACj on fat-suppressed T2 MRI at 24 months postoperatively were classified into the BME + group, and those with no BME were classified into the BME- group. Patient background, operation time, Japanese Orthopedic Association (JOA) score, re-tear rate, ACj tenderness, and cross-body adduction test were compared between groups. In addition, we examined the time of occurrence of BME.

RESULTS

A total of 345 ARCRs were performed during the study period. After the exclusion of 114 shoulders, the remaining 231 shoulders were included in this study. There were 208 cases in the BME- group and 23 cases in the BME + group. The incidence of BME was 9.96 %. Although the JOA scores of both groups showed a significant improvement postoperatively compared to preoperatively, there was no significant difference between the two groups. In terms of re-tear, there was 1 case in the BME + group and 7 in the BME- group. Positive ACj tenderness and cross-body adduction test were significantly higher in the BME + group (P < 0.001). BME occurred in 6 cases at 3 months, 9 cases at 6 months, and 8 cases at 1 year postoperatively. None of the patients developed BME at more than 1 year postoperatively. BME was observed on MRI in all cases at 2 years postoperatively.

CONCLUSIONS

The rate of occurrence of BME in the ACj after ARCR was 9.96 %. Patients with BME were significantly more likely to have ACj tenderness and positive cross-body adduction test. BME in the ACj often occurs within 6 months to 1 year after ARCR of small-to-medium rotator cuff tears, suggesting a relationship with postoperative functional improvement of the shoulder joint. The ACj should be considered as a potential site of persistent pain after ARCR for small-to-medium rotator cuff tears.

Arthroscopic Bankart repair with peeling osteotomy of the anterior glenoid rim preserves glenoid morphology

BACKGROUND

A decrease in the glenoid size after arthroscopic Bankart repair (ABR) was common in shoulders without osseous fragments compared with those with osseous fragments. For cases of chronic recurrent traumatic anterior glenohumeral instability without osseous fragments, we have performed ABR with peeling osteotomy of the anterior glenoid rim (ABRPO) to make an intentional osseous Bankart lesion. The aim of this study was to compare the glenoid morphology after ABRPO with it after simple ABR.

METHODS

The medical records of patients who underwent arthroscopic stabilization for chronic recurrent traumatic anterior glenohumeral instability were retrospectively reviewed. Patients with an osseous fragment, with revision surgery and without complete data were excluded. Patients were assigned to 1 of 2 groups: Group A, ABR without peeling osteotomy procedure or Group B, with ABRPO procedure. Computed tomography was performed preoperatively and 1 year after surgery. The size of the glenoid bone loss was investigated by the assumed circle method. The following formula was used to calculate the decreased size of the glenoid: (Δ) = (postoperative size of the glenoid bone loss) - (preoperative size of the glenoid bone loss). The size of the glenoid 1 year after surgery was assessed to determine if it had decreased (Δ > 0%) or not decreased (Δ ≤ 0%) relative to the preoperative size.

RESULTS

This study evaluated 39 shoulders divided into 2 groups: 27 shoulders in Group A and 12 shoulders in Group B. In Group A, postoperative glenoid bone loss was significantly greater than preoperative glenoid bone loss (7.8 ± 6.2 vs. 5.5 ± 5.3, respectively, P = .02). In Group B, postoperative glenoid bone loss was significantly lower than preoperative glenoid bone loss (5.6 ± 5.4 vs. 8.7 ± 4.0, respectively, P = .02). The P value for the interaction of group (A or B) × time (preoperative or postoperative) was 0.001. The decreased size of the glenoid was significantly larger in Group A than in Group B (2.1 ± 4.2 vs. -3.1 ± 4.5, respectively, P = .001). The rate of shoulders in which the size of the glenoid decreased 1 year after surgery relative to the preoperative size was significantly higher in Group A than in Group B (63% [17/27] vs. 25% [3/2], respectively, P = .04).

CONCLUSIONS

The study showed that ABRPO preserved the glenoid size better than simple ABR without a peeling osteotomy procedure.

Tranexamic acid has no effect on postoperative pain control after arthroscopic rotator cuff repair: A prospective, double-blind, randomized controlled trial

Background

The purpose of this study was to compare the efficacies of tranexamic acid (TXA) versus placebo after arthroscopic rotator cuff repair (ARCR).

Methods

This prospective, double-blind, and randomized study was conducted in 70 patients who underwent ARCR from 2021 to 2022 at our hospital. Thirty-four shoulders were randomly assigned to the TXA group, and 36 to the control group; TXA (10 mL) and normal saline (10 mL) were administered locally after surgery and in the control group, respectively. We evaluated visual analog scale pain scores at rest, during activity, and at night and the circumference and diameter of the shoulder joint in both groups preoperatively and at 1, 2, and 3 days, and 1 week after the surgery. We compared and analyzed the results between the groups. Statistical significance was set at a p-value of <0.05.

Results

There was no significant difference in the visual analog scale scores at rest, during activity, and at night between the groups (p > 0.05). The circumference and diameter of the shoulder joint were not also significantly different between both groups (p > 0.05).

Conclusion

Local TXA administration in patients who undergo ARCR does not significantly impact postoperative pain levels and the circumference and diameter of the shoulder joint.

Preemptive middle glenohumeral ligament release in arthroscopic rotator cuff repair does not reduce the postoperative stiffness: a retrospective comparative study

BACKGROUND

This study aimed to evaluate the efficacy of preemptive middle glenohumeral ligament (MGHL) release in arthroscopic rotator cuff repair (ARCR) to reduce postoperative stiffness.

METHODS

Patients who underwent ARCR were enrolled and allocated into two groups retrospectively: the preemptive MGHL release group (n = 44) and the preemptive MGHL non-release group (n = 42). Clinical outcomes were assessed and compared between the two groups, including the range of motion, Japanese Orthopedic Association Shoulder Score, Constant Shoulder Score, and the University of California, Los Angeles Score preoperatively and 3 months, 6 months, and 12 months postoperatively and complications. The integrity of the repaired tendon was assessed at the 12-month follow-up using magnetic resonance imaging.

RESULTS

There were no significant differences between the groups in all range of motion and all functional scores at any of the assessed time points. There was also no significant difference in the healing failure rate 2.3% in the preemptive MGHL group and 2.4% in the preemptive MGHL non-release group (p = .97), and postoperative stiffness was 2.3% in the preemptive MGHL group and 7.1% in the preemptive MGHL non-release group (p = .28). There was no postoperative instability in both group.

CONCLUSION

ARCR effectively facilitates the recovery of range of motion and function in patients with a rotator cuff tear. However, preemptive MGHL release could not be an effective method to reduce postoperative stiffness.

Comparison of clinical outcome and repair integrity after arthroscopic suture-bridge and triple-row rotator cuff repairs of Fosbury flop tears

BACKGROUND

The Fosbury flop tear (FFT) has recently been described as a rotator cuff tear that has flipped upon itself and adhered medially. FFT is known to have a high retear rate after arthroscopic rotator cuff repair. The cause of the high postoperative retear rate after arthroscopic rotator cuff repair is believed to be due to the inability to achieve anatomical reduction because of difficulties in reducing the torn tendon stump. Arthroscopic rotator cuff repairs using the triple-row technique may allow better anatomical reduction of the cuff tear when compared with the suture-bridge technique. We compared the clinical outcomes and cuff integrity of the triple-row and suture-bridge techniques in arthroscopic rotator cuff repair for FFT.

METHODS

Patients with small-to-medium sized cuff tears of the supraspinatus tendon alone who were diagnosed with FFT, underwent arthroscopic rotator cuff repair, and had 2 or more years of follow-up were included. A total of 34 shoulders underwent the triple-row technique and 22 shoulders underwent the suture-bridge technique. The following were compared between the two techniques: patient background, operation time, number of anchors used during the operation, Japanese Orthopedic Association (JOA) score, active range of motion, and retear rate.

RESULTS

No significant difference in patient background was found between the two techniques. Although active range of motion was significantly improved compared with preoperative scores, no significant difference was observed between techniques. The triple-row technique demonstrated a significantly higher 24-month postoperative JOA score, significantly shorter surgery time, significantly lower retear rate, and significantly larger number of anchors used during the operation.

CONCLUSIONS

The triple-row technique was an effective method compared with the suture-bridge technique in cases with FFT.

Tranexamic acid administration for arthroscopic rotator cuff repair: A prospective, double-blind, randomized controlled trial

BACKGROUND

The purpose of this study was to compare the efficacy of tranexamic acid versus placebo after arthroscopic rotator cuff repair.

METHODS

This prospective, double-blind, and randomized study involved 66 patients who consecutively underwent arthroscopic rotator cuff repair from 2020 to 2021 at our hospital. Thirty-three shoulders each were randomly assigned to the tranexamic acid and control groups. In the former group, 1000 mg of tranexamic acid (20 mL) was administered intravenously 10 min before surgery and the same volume of normal saline (20 mL) was administered intravenously in the control group. We evaluated visual clarity; visual analog scale pain scores at rest, during activity, and at night; the circumference and diameter of the shoulder joint in the groups before and after the surgery at 1, 2, and 3 days, and 1 week; estimated perioperative blood loss; and operative time. Visual clarity was rated using a numeric rating scale from grade 1 (poor) to grade 3 (clear) every 15 min throughout the surgery. We compared and analyzed the results between the groups. Statistical significance was set at a p-value of <0.05.

RESULTS

Visual clarity was found to be significantly better in the tranexamic acid group, with a greater percentage of grade 3 visual clarity (75.6 ± 11.2% vs 68.1 ± 13.4%, p = 0.045). The visual analog scale scores at rest and at night in the control group were significantly lower than those in the tranexamic acid group for 1 week postoperatively (13.8 ± 14.8 vs 5 ± 9.3, p = 0.008, 36.1 ± 23.3 vs 19.3 ± 24, p = 0.012). The circumference and diameter of the shoulder joint, estimated perioperative blood loss, and operative time were not significantly different between the two groups.

CONCLUSION

Intravenous administration of tranexamic acid is an alternative way to improve visual clarity in arthroscopic rotator cuff repair; however, there are no other significant differences compared to the administration of placebo.

Return to sports after arthroscopic Bankart repair in teenage athletes: a retrospective cohort study

BACKGROUND

Anterior shoulder instability is frequent among young athletes. Surgical treatment for this injury aims to facilitate an early return to sports (RTS). However, the rate of recurrent instability after surgery is reportedly high among young patients, and it is unclear whether surgery ensures satisfactory RTS. The purpose of this study was to verify the clinical outcomes and RTS after arthroscopic Bankart repair in competitive teenage athletes without critical bone loss in the glenoid.

METHODS

We retrospectively reviewed competitive teenage athletes who underwent arthroscopic Bankart repair. Patients with large bony defects in the glenoid, larger than 20% of the healthy side, were excluded. Clinical outcomes, recurrent instability, the final level of RTS, and the time needed for RTS were analyzed.

RESULTS

In total, 50 patients with a mean follow-up period of 44.5 ± 19.6 (range, 24-85 months) months were included. The mean age at surgery was 16.8 ± 1.7 (range, 13-19 years) years. Two patients (4.0%) experienced recurrent instability. All patients returned to sports, 96% of patients participated competitively, and 76% achieved a complete return to the pre-injury level without any complaints. The time for RTS was 6.6 ± 2.7 months (range, 3-18 months), to competitions was 9.3 ± 4.0 (range, 6-24 months) months, and to complete return was 10.6 ± 4.3 (range, 8-24 months) months. The complete return rates varied by sports type, with 82% in contact athletes, 59% in dominant-hand overhead athletes, and 100% in other athletes (P = 0.026). Other preoperative factors or concomitant lesion such as bony Bankart, superior labrum tear, or humeral avulsion of glenohumeral ligament lesion did not affect the complete RTS.

CONCLUSION

Arthroscopic Bankart repair is an effective surgical procedure for anterior shoulder instability, even among competitive teenage athletes. Sports type was the only factor associated with complete RTS after surgery.

Arthroscopic treatment of massive acromioclavicular joint ganglion cysts with color-aided visualization: a case series of 4 patients

Background

Acromioclavicular joint ganglion cysts are rare lesions that mainly arise from the degeneration of the acromioclavicular joint in elderly patients. Although surgical management may be required because of their high recurrence rate after aspiration, few reports have described arthroscopic surgical procedures to treat acromioclavicular ganglion cysts. We report the surgical results of arthroscopic ganglionectomy with color-aided visualization for massive acromioclavicular ganglion joint cysts.

Methods

This retrospective case series examined patients identified with massive ganglion cysts that were localized above the acromioclavicular joint. All patients underwent an arthroscopic removal of subacromial synovium and subsequent injection of indigo carmine into the ganglion. The distal end of the clavicle was excised arthroscopically from the inferior surface, and the ganglion stalk was confirmed using indigo carmine for enhanced visualization and magnification. A ganglion portal was created, and the ganglion cyst was resected with the aid of the dye.

Results

Four female patients, aged 78-90 years, were identified with a massive acromioclavicular joint ganglion cyst. Plain radiography showed joint degeneration in the acromioclavicular joint, and magnetic resonance imaging scans showed fluid-filled mass formation. Although all patients initially underwent multiple aspirations of the ganglion cyst, we opted for surgical intervention because of its persistent recurrence. Three patients exhibited concurrent rotator cuff tears, and one patient had a prior history of cuff repair with no retear. After arthroscopic ganglionectomy with color-aided visualization for massive acromioclavicular ganglion joint cysts, none of the patients have shown recurrences at 2 years postoperatively.

Conclusion

Novel aspects of this case series include the use of indigo carmine to provide a better visualization and identification of the ganglion stalk under arthroscopy. Furthermore, a ganglion portal is useful for achieving complete resection of the indigo carmine-stained ganglion cyst. Color-aided visualization using indigo carmine and the construction of a ganglion portal were useful techniques for performing arthroscopic ganglionectomy in patients with a massive acromioclavicular joint ganglion cyst.

Return to sports after arthroscopic bankart repair on the dominant shoulder in overhead athletes

BACKGROUND

Arthroscopic Bankart repair (ABR) yields good results in young athletes with anterior shoulder instability. However, the treatment for overhead athletes is challenging because recovery of range of motion is necessary for return to play and repeated shoulder motion may lead to recurrent instability. The aim of this study was to investigate the clinical outcomes and return to sports after ABR on the dominant shoulder in overhead athletes.

METHODS

This study included 24 competitive level overhead athletes who underwent ABR on their dominant shoulders. The mean age at surgery was 17.6 years, and the mean follow-up was 39.7 months. The range of bilateral shoulder motion, the Rowe score, the Japanese Shoulder Society Shoulder Instability Score (JSS-SIS), and the Japanese Shoulder Society Shoulder Sports Score (JSS-SSS) were evaluated before the surgery and at the final visit. Recurrent instability, the final level of return to sports, and the duration before returning to sports were confirmed, as well as the pre-, intra- and postoperative factors, which prohibited complete return to play.

RESULTS

There were no cases of recurrent instability. The Rowe score, JSS-SIS, JSS-SSS, and the range of flexion, abduction, internal rotation significantly improved postoperatively. Fifteen athletes (62.5%) returned to the same or superior levels without any complaint in their shoulders. The mean duration needed for a complete return was 13.3 months. The postoperative external rotation deficit in abduction was larger in the athletes who returned incompletely than those who returned completely, 7.8° and 2.3°, respectively.

CONCLUSIONS

ABR is a reliable surgery for preventing recurrent instability in overhead athletes, however the rate of a complete return to preinjury level was low and a long duration was needed for complete return to play. The postoperative external rotation may be necessary for a complete return to overhead sports.

LEVEL OF EVIDENCE

Level IV: Retrospective Case Series.

The relationship between clinical outcomes of arthroscopic rotator cuff repair and hemoglobin A1c

Background

The clinical outcomes of diabetic patients who underwent arthroscopic rotator cuff repair have been reported. However, few studies have focused on the relationship between these clinical outcomes and postoperative hemoglobin A1c. This study compared clinical outcomes of diabetic patients with a hemoglobin A1c < 7% to those with a hemoglobin A1c ≥ 7% at 12 months post-arthroscopic rotator cuff repair.

Methods

This retrospective study involved 51 consecutive patients who underwent arthroscopic rotator cuff repair from 2015 to 2020. Approximately 26 and 25 shoulders were assigned to a Low group (hemoglobin A1c < 7%) and High group (hemoglobin A1c ≥ 7%) at 12 months postoperatively, respectively. Patients with poorly controlled diabetes were preoperatively hospitalized for perioperative diabetic control. Clinical outcomes were shoulder range-of-motion, Constant Shoulder Score, and University of California, Los Angeles Score preoperatively and at 12 months postoperatively. Complications were also evaluated.

Results

Both groups showed significant improvement in their range-of-motion, Constant Shoulder Score, and University of California, Los Angeles score at 12 months post-arthroscopic rotator cuff repair (p < 0.05) except external rotation in High group. These improvements were significantly inferior in the High group compared to the Low group (Low/High group; 167.3 ± 7.7°/159.5 ± 16.3° for forward flexion; p = 0.013, 94.9 ± 7.6/90.1 ± 9.9 points for Constant Shoulder Score; p = 0.033, 32.6 ± 3.6/30.6 ± 4.1 points for University of California, Los Angeles score, p = 0.037). Hemoglobin A1c at 12 months postoperatively was also significantly inferior in the High group (Low/High group; 6.5 ± 0.3%/7.6 ± 0.8%; p < 0.05). The rate of rotator cuff retear was not significantly different between groups (Sugaya type4; p = 0.49, type5; p = 0.322) and there were no cases of infection or shoulder stiffness in either group.

Conclusion

Diabetic patients showed improvement of their range-of-motion and function after arthroscopic rotator cuff repair; however, patients with poorly controlled diabetes had significantly inferior improvement.

Clinical outcome and repair integrity after arthroscopic full-thickness rotator cuff repair: Triple-row versus suture-bridge techniques

BACKGROUND

This study aimed to compare the clinical outcomes and cuff integrity of the triple-row technique and suture-bridge technique in arthroscopic rotator cuff repair.

METHODS

Among patients with more than two years of follow-up (mean 27.4 ± 7.2 months), 71 shoulders that underwent the triple-row technique (46 male and 25 female; mean age, 62.7 ± 10.1 years; small-to-medium tears, 42 shoulders; large-to-massive tears, 29 shoulders) and 64 shoulders that underwent the suture-bridge technique (43 male and 21 female; mean age, 65.5 ± 8.4 years; small-to-medium tears, 46 shoulders; large-to-massive tears, 18 shoulders) were examined. The patient background, operation time, number of anchors used during the operation, Japanese Orthopedic Association (JOA) score, Active range of motion, and retear rate were evaluated and compared between the two techniques.

RESULTS

There was no significant difference in the patient background between the two techniques. The JOA score and Active range of motion were significantly improved compared to preoperative scores; however, there were no difference between the two techniques. The number of anchors used during the operation was 5.4 ± 1.6 for the triple-row technique and 4.1 ± 1.9 for the suture-bridge technique. Although significantly more anchors were used for the triple-row technique, there was no significant difference in the operation time between the two techniques. The retear rate was 7.1% for small-to-medium tears and 3.4% for large-to-massive tears using the triple-row technique, and 10.9% for small-to-medium tears and 33.3% for large-to-massive tears using the suture-bridge technique. The retear rate was significantly lower in large-to-massive tears when using the triple-row technique.

CONCLUSION

The triple-row technique was an effective method compared to the suture-bridge technique in cases with large-to-massive tears.

Expression of Substance P and Nerve Growth Factor in Degenerative Long Head of Biceps Tendon in Patients with Painful Rotator Cuff Tear

Purpose

Degenerative long head of biceps tendon (LHBT) has been recognized as a notable pain source in patients with rotator cuff tear (RCT). Tenotomy or tenodesis of LHBT is frequently indicated together with arthroscopic rotator cuff repair (ARCR) aiming for complete pain relief; however, it has not been fully investigated whether resected LHBT is really a source of pain. The purpose of this study was to investigate expression levels of pain-associated mediators in LHBT and its association with preoperative pain profiles.

Methods

Twenty-seven RCT patients who underwent ARCR with LHBT resection were included. Each LHBT was resected due to its abnormal arthroscopic findings including tenosynovitis, hypertrophy, and partial tear. Worst macroscopic lesion of the LHBT was obtained, and expression levels of substance P (SP) and nerve growth factor (NGF) were evaluated using enzyme-linked immunosorbent assay (ELISA). Ten healthy knee flexor tendons were analyzed as non-degenerative samples. Preoperatively, subjective shoulder pain VAS and pain duration were investigated. Conventional LHBT pain provocation tests (Speed, Yergason, O’Brien) were performed. Pressure pain threshold (PPT) of bilateral LHBT on the groove was recorded.

Results

Levels of SP and NGF expression were significantly higher compared with non-degenerative tendons (P<0.01). Shoulder pain VAS and pain duration were not directly associated with SP and NGF expression level. Patients with positive O’Brien test expressed greater SP than negative patients (P=0.001). Significant negative correlation between the PPT ratio (ipsilateral/contralateral) and SP expression level was observed (r=−0.453, P=0.034).

Conclusion

Greater expression of SP and NGF in degenerative LHBT supported our hypothesis that it would be a pain source in RCT patients. SP was likely to be expressed highly in patients with localized pressure pain hypersensitivity and positive O’Brien test (ie, altered mechanistic pain profile of LHBT), which may help when considering simultaneous LHBT resection during ARCR.

Clinical Registration

UMIN000023943.

Factors affecting the outcome of septic arthritis of the shoulder joint with arthroscopic management

BACKGROUND

Good results have been reported with arthroscopic therapy of septic arthritis of the shoulder; however, few studies have focused on the risk factors for failure of arthroscopic surgery. The purpose of this study was to identify the risk factors affecting the recurrence or death post-surgery in cases of septic arthritis of the shoulder.

METHODS

We retrospectively assessed the records of patients who underwent surgical treatment for septic arthritis of the shoulder between 2009 and 2019. Patients were divided into 2 groups based on complete recovery, recurrence, or death after a single arthroscopic surgery: the eradicated group and the recurred/death group. To identify risk factors for the failure of arthroscopic surgery for septic arthritis of the shoulder, the following parameters were considered: age, sex, presentation of a rotator cuff tear, the arthroscopic staging of the infection, diabetes mellitus, the causative organism, preoperative white blood cell count, and C-reactive protein level in blood. We compared two groups with respect to the presence of potential risk factors.

RESULTS

This study included 22 patients with a mean age of 67.9 years. Septic arthritis of the shoulder was eradicated completely with a single arthroscopic surgery in 17 patients (77.3%). However, failure of the surgery resulting in recurrence or death was observed in 5 patients (22.7%). No significant differences were observed in other parameters between the two groups except for the causative organism. Methicillin-resistant Staphylococcus aureus was found in 1 patient (5.9%) in the eradicated group. On the other hand, Methicillin-resistant S. aureus was found in 3 patients (60%) in the recurred/death group (p = 0.024).

CONCLUSION

Most patients with septic arthritis of the shoulder are effectively treated with a single arthroscopic surgery. This study suggests that Methicillin-resistant S. aureus as the causative organism may be the most important prognostic factor in these cases.

Post-operative pain control following arthroscopic rotator cuff repair: Intravenous acetaminophen versus interscalene brachial plexus block; A prospective randomized study

Background

With the increasing number of patients undergoing arthroscopic rotator cuff repair (ARCR), postoperative pain control in these patients has become an important issue. We investigated and compared post-operative pain relief with intravenous acetaminophen (IA) and interscalene brachial plexus block (IBPB) after ARCR.

Methods

This prospective study involved 66 consecutive patients who underwent ARCR in 2019-2020 at our hospital. Overall, 23 and 43 shoulders were assigned to the IA and IBPB groups, respectively. We evaluated the visual analog scale (VAS) pain scores at rest, during activity, and at night for the first 72 h postoperatively. We compared the results statistically between the groups. A p-value <0.05 was considered statistically significant.

Results

VAS scores for night pain in the IBPB group were significantly lower than those in the IA group for the first 24 h postoperatively (p = 0.017). In contrast, the same scores were significantly lower in the IA group than in the IBPB group at 72 h postoperatively (p = 0.024). Other scores were not significantly different between the groups.

Conclusions

IBPB provides superior night pain control during the first 24 h postoperatively, and IA provides superior night pain control at 72 h postoperatively. However, there were no significant differences in other pain scores between the two groups.

Clinical results of arthroscopic rotator cuff repair in diabetic and non-diabetic patients

BACKGROUND

Although the clinical outcomes of arthroscopic rotator cuff repair (ARCR) have been reported, few studies have focused on diabetic patients. We investigated and compared the clinical results of ARCR in patients with and without diabetes.

METHODS

This retrospective study involved 195 consecutive patients who underwent ARCR from 2015 to 2018 in our hospital. Twenty-seven and 168 shoulders were assigned to diabetes and non-diabetes groups, respectively. Diabetic patients with poor control were preoperatively hospitalized for perioperative diabetic control. We evaluated range of motion (ROM), Japanese Orthopaedic Association shoulder (JOA) score, Constant Shoulder Score, and University of California, Los Angeles (UCLA) score preoperatively and at 6 months and 1 year post-ARCR. Rates of rotator cuff retear 1 year post-ARCR and preoperative and postoperative stiff shoulder were also evaluated. We compared the results between groups and analyzed them statistically. A p-value of <0.05 was considered statistically significant.

RESULTS

Preoperative ROM, JOA score, Constant Shoulder Score and UCLA scores showed significant improvement at post-ARCR in both groups (p < 0.05). On comparing the groups, although preoperative JOA score and Constant Shoulder Score were significantly lower in diabetes group than in non-diabetes group (diabetic/non-diabetic group; 60.0/65.3 for JOA score; p = 0.003, 59.7/64.2 for Constant Shoulder Score; p = 0.003), there was no significant difference postoperatively (6 months post-ARCR; 88.0/89.7 for JOA score; p = 0.783, 88.1/88.6 for Constant Shoulder Score; p = 0.597, 1 year post-ARCR; 96.7/95.4 for JOA score; p = 0.238, 96.6/95.4 for Constant Shoulder Score; p = 0.248). Furthermore, preoperative and postoperative stiff shoulder and retear rates were not significantly different between groups (p = 0.152, p = 0.344, p = 0.347, and p = 0.563, respectively).

CONCLUSION

Diabetic patients showed comparable clinical results with non-diabetic patients post-ARCR. Perioperative diabetic control may be recommended for preoperatively uncontrolled diabetic patients.

Morphological characteristics of the acromion in Fosbury flop tears and their clinical outcomes after arthroscopic rotator cuff repair

Background

Rotator cuff tears that have flipped upon itself and adhered medially have been recently described as Fosbury flop tears (FFT). However, there are no reports on the cause and clinical outcomes of FFT. We investigated the preoperative anatomical factors and clinical outcomes related to the occurrence of FFT.

Methods

Among patients with more than two years of follow-up, 33 patients with FFT who underwent arthroscopic rotator cuff repair (ARCR) for a small-to-medium sized tear of the supraspinatus tendon alone (Group F: mean age, 63.4 ± 8.9 years) and 52 patients without FFT who underwent ARCR (Group C: mean age, 62.1 ± 7.0 years) were included. Presence of diabetes mellitus, critical shoulder angle (CSA), lateral acromial angle (LAA), acromiohumeral distance (AHD), sagittal and coronal morphologies of the acromion, JOA score, and rate of rotator cuff re-tear were evaluated.

Results

There were significantly more males in Group F (P = 0.017). There were no significant differences in age or rate of diabetic complications. The mean CSA, LAA, and AHD in the Groups F and C were respectively as follows: CSA, 33.7 ± 4.0° and 34.5 ± 3.4°; LAA, 82.1 ± 9.9° and 82.1 ± 6.9°; AHD, 10.2 ± 1.4 mm and 9.8 ± 1.4 mm. There were no significant differences between groups. The acromial morphology showed no significant difference in the sagittal plane; however, significantly more double-floor type acromia were found in the coronal plane (P < 0.001). Although the JOA score significantly improved in both groups, there was no significant difference between groups. The re-rupture rate was significantly higher in Group F than Group C (15.2% versus 1.9%; P = 0.02).

Conclusions

Double-floor type acromia in the coronal plane was common in Group F. The location of osteophytes on the inferior surface of the acromion was believed to be associated with the occurrence of FFT. Furthermore, a high re-tear rate was observed in group F.

Ultrasonographic analysis of the extensor carpi radialis brevis in asymptomatic individuals

BACKGROUND

Tennis elbow is characteristically seen as damage at the extensor carpi radialis brevis (ECRB) on ultrasonography. In this study, damage at the origin of the ECRB was investigated using ultrasonography in elbows without complaints pertaining to the joint.

METHODS

We investigated 282 elbows on the dominant side in volunteers who consented to participate in the study and had no complaints or history of trauma to either elbow, no tenderness in the lateral epicondylar region on physical examination, and no pain upon resisted extension of the wrist and/or middle finger with the elbow extended (162 men, 120 women; mean age 62 years, range 21-84 years). On ultrasonography, damage at the origin of the ECRB was defined as low echo or disruption in fiber orientation. Comparison between groups with and without damage was performed based on age, sex, history of sports activity involving the upper extremity, and history of work involving loading of the upper extremity.

RESULTS

Of the 282 elbows, damage was noted in 60 (21.3%). Comparing the groups with and without damage, mean ages were 66.2 (40-80) years and 60.9 (21-84) years. The group with damage included 31 of 162 (18.1%) male elbows and 29 of 110 (26.4%) female elbows; 10 of 64 elbows (15.6%) had a positive history of sports involving the upper extremity and 50 of 218 elbows (22.9%) had no history; 16 of the 64 elbows (25.0%) had a positive history of work involving loading the upper extremity and 44 of the 218 elbows (20.2%) had no history. Age was significantly higher in the group with damage. The group with damage showed no significant differences in other categories.

CONCLUSIONS

Asymptomatic damage at the ECRB origin was noted in 21.3% of elbows at higher ages, but there was no association with sports or work.

Secondary frozen shoulder after traumatic anterior shoulder instability

Background

Secondary frozen shoulder after traumatic anterior shoulder instability is rare. The therapeutic management and clinical outcome of this condition are not well known. This study aimed to investigate the characteristics of such rare cases and verify treatment outcomes.

Methods

We reviewed the cases of 12 patients with secondary frozen shoulder after anterior shoulder dislocation or subluxation between April 2007 and March 2018. All patients underwent physical therapy along with an intra-articular injection. Patients with refractory stiffness received arthroscopic mobilization. The range of motion, Rowe score, and University of California, Los Angeles score were evaluated at the first and final visits. A telephone survey was performed to determine the long-term outcomes including recurrent instability, the Oxford Shoulder Score, and the Oxford Instability Score.

Results

The mean age of patients at the first visit was 42.5 years. Two patients underwent surgical treatment, which revealed scar-like tissue of the anteroinferior capsule. The range of motion, Rowe score, and University of California, Los Angeles score significantly improved at a mean follow-up of 15 months. At a mean follow-up of 82 months, the telephone survey revealed recurrent instability in 1 patient who was conservatively treated; the average Oxford Shoulder Score and Oxford Instability Score were 46.4 and 43.2, respectively.

Conclusions

The average patient age observed in this study was higher than the known peak age of traumatic anterior shoulder instability occurrence. Less activity, loss of capsule elasticity, or scarring after a capsular tear may lead to stiffness after traumatic anterior shoulder instability. Conservative treatment can be used as the first-line therapy, followed by effective arthroscopic mobilization when conservative treatment fails.

Incidence of Cutibacterium acnes in arthroscopic Bankart repair for traumatic anterior shoulder instability

Background

We evaluated the detection rate of Cutibacterium acnes (C. acnes) for patients who underwent arthroscopic Bankart repair for traumatic anterior shoulder instability.

Methods

Study subjects included 36 patients who underwent arthroscopic Bankart repair. Skin swabs prior to antisepsis, intraoperative synovial swabs of the glenohumeral joint (immediately after incision and prior to wound closure), and the suture of the suture anchor were cultured. Evaluation criteria included the detection rate of C. acnes in multiple regions of the body.

Results

Using a skin swab culture test, C. acnes was detected in 63 of 108 samples (58.3%). The bacterium was detected in 2 of 36 samples (5.5%) and 4 of 36 (11.1%) in the synovial swab culture of the glenohumeral joint immediately after surgical incision and immediately before wound closure, respectively. In the suture culture of the suture used in the arthroscopic Bankart repair, C. acnes was detected in 1 of 36 samples (2.8%).

Conclusions

C. acnes was detected in patients undergoing surgeries for shoulder instability. The relationship between C. acnes and the pathological condition of shoulder instability remains unknown.

Incidence of Propionibacterium acnes in arthroscopic rotator cuff repair

BACKGROUND

Recently, Propionibacterium acnes was reported to be involved in postsurgical outcomes. We investigated the detection rate of P. acnes and clinical features of P. acnes infection following arthroscopic rotator cuff repair.

METHODS

Samples were collected from skin swabs before preparation, swabs of the synovium, sutures, and swabs from the arthroscope tip. We evaluated age, sex, presence of diabetes mellitus, preoperative contracture, operation time, blood test, Japanese Orthopaedic Association (JOA) scores, cuff integrity, deep infection, and positive inoculation rate.

RESULTS

We studied 90 patients (59 men and 31 women). Mean age was 60.6 years. Cultures of P. acnes showed a 65.5% positive superficial colonization rate (78.0%, male; 41.9%, female). Among the synovium swabs, P. acnes was detected in 13.6% and 0% of patients positive and negative for skin colonization with P. acnes, respectively. Positive culture was not correlated with age, sex, presence of diabetes mellitus, preoperative contracture, blood test, JOA score, cuff integrity, deep infection, operation time, and blood test date.

CONCLUSIONS

P. acnes was detected at a higher rate in the skin of male patients. Patients with P. acnes detected on the skin showed higher rates of detection in the synovium. These findings suggest that the route of infection is via contamination.

LEVEL OF EVIDENCE

Diagnostic level III; Case-control study.

Clinical Results and Complications of Shoulder Manipulation under Ultrasound-Guided Cervical Nerve Root Block for Frozen Shoulder: A Retrospective Observational Study

Introduction

Manipulation under ultrasound-guided fifth and sixth cervical nerve root block (MUC) is a recognized form of treatment for patients with persistent frozen shoulder (FS). This study aimed to investigate the confirmatory hypothesis testing that the MUC has a significant clinical effect on FS refractory to conservative treatments and to assess its adverse events.

Methods

This is a retrospective observational study on patients with FS treated in the past 8 years. Although 77 patients were eligible for this study, only 68 were enrolled. The patients were evaluated immediately before the MUC and at 1, 3, and 6 months after with the use of the Japanese Orthopaedic Association shoulder score. Simultaneously, ranges of motion of the affected shoulder were measured in two directions: forward flexion and external rotation. A paired t test or a Wilcoxon signed-rank test was used to compare differences in outcomes between before and 6 months after MUC. We also assessed any adverse events during and after the MUC.

Results

Regarding the primary outcome, confirmatory testing showed statistically significant improvements in every outcome value at 6 months after MUC (p < 0.001). In terms of adverse events, two patients (2.9%) had vasovagal reflex, one (1.5%) had a panic attack during the block procedure, and a 72-year-old female patient (1.2%) had an avulsion fracture of the inferior glenoid during the manipulation procedure, although all of them recovered spontaneously without any residual functional impairment.

Conclusion

The results showed that significant clinical effects of the MUC on FS were observed through a confirmatory analysis with a sufficient sample size. However, several complications that could occur during the block and manipulation procedures should be considered.

Can arthroscopic Bankart repairs using suture anchors restore equivalent stability to open repairs in the management of traumatic anterior shoulder dislocation? A meta-analysis

BACKGROUND

Recently, arthroscopic Bankart repairs have become much more popular than open repairs for the treatment of recurrent anterior shoulder instability. However, it is unclear whether the modern arthroscopic Bankart repairs using suture anchors could restore equivalent stability to open repairs. We conducted a meta-analysis to compare arthroscopic Bankart repairs using suture anchors and open repairs in regard to clinical outcomes.

METHODS

A literature review was performed according to the PRISMA guidelines. PubMed was searched from January 1966 to January 2017. Studies were identified using the terms 'anterior shoulder dislocation' or 'recurrent anterior shoulder dislocation' and 'Bankart repair'. The search yielded 36 publications. After reading the full-text articles, we included four randomized controlled trials and five retrospective studies that compared arthroscopic and open repairs using suture anchors.

RESULTS

No significant differences were found between the two procedures in frank re-dislocation and revision surgery due to recurrence. However, the overall recurrent instability including not only re-dislocation but also subluxation and apprehension was significantly higher in arthroscopic repairs than in open repairs, while a significantly higher Rowe score and lower loss of external rotation at 90° of abduction were observed following arthroscopic repairs compared to open repairs.

CONCLUSIONS

Modern arthroscopic Bankart repairs using suture anchors provide an equivalent outcome compared to open repairs in terms of apparent re-dislocation, but overall recurrent instability including subluxation or apprehension was still significantly higher in arthroscopic repairs than in open repairs.

Organotropic chemopreventive effects of n-3 unsaturated fatty acids in a rat multi-organ carcinogenesis model

Organotropic chemopreventive effects of n-3 unsaturated fatty acids were studied using a multi-organ carcinogenesis model in male rats. Rats were treated with diethylnitrosamine (DEN), N-methyl-N-nitrosourea (MNU), N-butyl-N-4-hydroxybutylnitrosamine (BBN), 1,2-dimethylhydrazine (DMH) and dihydroxy-di-n-propylnitrosamine (DHPN) during the first 7 weeks, and then given unsaturated fatty acid (UFAs), docosahexaenoic acid (n-3, C(22:6)) (DHA), eicosapentaenoic acid (n-3, C(20:5)) (EPA), linoleic acid (n-6, C(18:2)) (LA) or oleic acid (n-9, C(18:1)) (OA) at a dose of 1.0 ml/rat, 3 times a week by gavage for the consecutive 30 weeks. All rats were fed a low LA basal diet throughout the experiment and a calorie-restricted basal diet during the period of UFAs feeding administration. DHA significantly reduced tumor size and numbers in the large intestine as compared to OA treatment. Furthermore, DHA showed a tendency to inhibit carcinogenesis in the small intestine and lung. EPA also showed a tendency to inhibit intestinal carcinogenesis. On the other hand, LA showed a tendency to inhibit lung carcinogenesis, but to promote large intestinal carcinogenesis. However these UFAs did not influence preneoplastic and neoplastic lesion development in the liver, kidney, and urinary bladder. Levels of the administered fatty acids were clearly increased in the serum and organs. In contrast, arachidonic acid (AA) levels in the large and small intestines and liver were markedly decreased by treatment with DHA and EPA. Decreased levels of AA in the large intestine correlated well with tumor incidence, although the number of glutathione S-transferase-positive (GST-P(+)) foci showed an inverse correlation with AA levels. The data thus provide evidence that an organotropism exists with regard to the influence of UFAs on carcinogenesis, which correlates with reduction of tissue AA levels in the target organs.

Hematological studies on black cumin oil from the seeds of Nigella sativa L

The methanol soluble portion of black cumin oil, which is prepared by compression of seeds of Nigella sativa L., showed inhibitory effects on arachidonic acid (AA)-induced platelet aggregation and blood coagulation. By bioactive assay of AA-induced platelet aggregation, the methanol soluble part was purified to isolate a new compound 2-(2-methoxypropyl)-5-methyl-1,4-benzenediol (1) and two known compounds, thymol (2), carvacrol (3), having very strong inhibitory activity. Further, we then examined the isolated compounds (1-3) and eight related compounds by the screening test for AA-induced platelet aggregation. Compounds possessing aromatic hydroxyl and acetoxyl group had more potent activity than aspirin, which is well known as a remedy for thrombosis.

Establishment and characterization of three new rat renal cell carcinoma cell lines from N-ethyl-N-hydroxyethylnitrosamine-induced basophilic cell tumors

Three new rat cell lines (designated as BP13, BP30 and BP36B), derived from rat basophilic-type renal cell carcinomas induced with N-ethyl-N-hydroxyethylnitrosamine, were established and characterized. Passaged up to 100 times in vitro for 3 years, each cell line forms epithelial monolayers with cell cycles for BP13, BP30 and BP36B of 29, 21 and 17 h, respectively. Positive glucose-6-phosphate dehydrogenase (G6PD) and gamma-glutamyltransferase (gamma-GT) activity in their cytoplasm, but negative succinate dehydrogenase (SD) and slightly positive carbonic anhydrase type II (CA) localization indicates an origin from proximal tubules. Ultrastructural examination showed the presence of variable numbers of mitochondria and many microvilli and intracellular junctions on the plasma membrane. BP13 and BP30 were found to be tetraploid and BP36B diploid. BP13 has one marker chromosome 15p+, and BP36B an isochromosome of 1q. Anchorage-independent growth and tumorigenicity in immunosuppressed nude mice of BP13 and BP36B, but not BP30, proved their neoplastic nature. These three cell lines should provide useful tools for studying the biological characteristics of renal cell tumors.

Histogenetic stereological reconstruction of rat basophilic, clear, and oncocytic neoplastic renal cell lesions using carbonic anhydrase type II-PAS double-stained sections

The histogenesis of 3 types of rat renal cell tumors (basophilic cell, clear cell, and oncocytic) was stereologically analyzed, with particular attention paid to transitions from normal tubules. Early nitrosamine-induced preneoplastic lesions, including dysplastic tubules (altered tubules), epithelial hyperplasias, and small adenomas, were reconstructed using serially sectioned specimens processed for carbonic anhydrase type II (CA) and periodic acid-Schiff (PAS) (CA-PAS) double staining to allow easier distinction of the nephron segments: Proximal tubules had a PAS-positive brush border and were weakly positive for CA in the cytoplasm; distal tubules were PAS negative and weakly positive for CA; collecting ducts were PAS negative and strongly positive for CA. Similarly, cytochrome c oxidase (CytOx) and CytOx-PAS double staining was also applied to confirm the character of oncocytic lesions. All basophilic lesions (7 of 7) showed transition to proximal tubules. Clear cell lesions positive for CA, on the other hand, showed transition to distal tubules in 4 of 9 (44.4%) lesions and to collecting ducts in 4 of 9 (44.4%) lesions, but in only 1 of 9 (11%) to a proximal tubule. All oncocytic lesions (16 of 16), characterized by positivity for both CA and CytOx, showed transition to collecting ducts. The results indicate that the origins of renal cell neoplasia are proximal tubules for the basophilic cell lesions, either proximal or distal tubules for their clear cell counterparts, and collecting ducts for oncocytic lesions.

The surgical treatment of a haemophilic pseudotumour in an extremity: a report of three cases with pathological fractures

A haemophilic pseudotumour is a rare complication of haemophilia occurring in 1-2% of patients with a factor VIII or IX deficiency. This report presents three surgical cases of pseudotumours involved in a pathological fracture in the extremities. All cases showed a favourable post-operative course. If the preoperative management is appropriately designed, a limb salvage operation for a pathological fracture due to a pseudotumour could be carried out successfully. Before choosing amputation of a limb, the surgeon should consider the possibility of limb salvage.

Selective neutrophil depletion with monoclonal antibodies attenuates ischemia/reperfusion injury in skeletal muscle

The purpose of this study was to determine whether depletion of circulating neutrophils, using an antineutrophil monoclonal antibody (RP3), would attenuate ischemia/reperfusion injury in rat skeletal muscle. A 3- and 5-hr period of ischemia was induced unilaterally into the hindlimbs of rats; the isolated limbs were then reperfused for 24 hr after ischemia. The gastrocnemius muscle was then removed, and blood was taken simultaneously. The hematologic parameters were measured, muscle neutrophil sequestration was assessed by myeloperoxidase (MPO) activity, free radical production was evaluated by the tissue lipid peroxides (LPO) levels, muscle viability was assessed by tissue levels of adenosine triphosphate (ATP) and creatine phosphate (PCr) levels, and muscle wet/dry weights were determined. Treatment with RP3 selectively and sufficiently depleted the circulating neutrophil population, markedly reduced MPO, and significantly attenuated LPO and the tissue water content after both 3- and 5-hr of ischemia. After 3 hr of ischemia, ATP and PCr levels were significantly increased by neutrophil depletion; however, after 5 hr of ischemia, the same effect was not demonstrated. These results suggest that neutrophil depletion after 3 hr of ischemia restrains free radical production and edema formation, and also attenuates skeletal muscle ischemia reperfusion injury; however, after 5 hr of ischemia, ischemic damage was so severe, that neutrophil depletion did not reduce ischemia reperfusion injury.

Activin exerts a neurotrophic effect on cultured hippocampal neurons

Activin is a member of the transforming growth factor (TGF)-beta superfamily, which comprises a growing list of multifunctional proteins that serve as regulators of cell proliferation and differentiation. Recently, activin was shown to regulate the neurotransmitter phenotype in peripheral neurons. It is also a potent survival factor for neurogenic clonal cell lines, retinal neurons and midbrain dopaminergic neurons. We have studied the effect of activin on hippocampal cells which show abundant expression of activin receptors or binding sites. Exposure of primary cultures of rat hippocampal neurons to activin supported neuronal survival. This neurotrophic action of activin was blocked by treatment with the tyrosine kinase inhibitor genistein or the protein kinase C inhibitor calphostin C. However, the Ca2+/calmodulin kinase inhibitor KN-62 had no effect. Nicardipine, a blocker of the L-type Ca2+ channel, also inhibited the neurotrophic effect of activin. Furthermore, activin potentiated the depolarization-induced elevation in intracellular Ca2+ concentration ([Ca2+]i). The neurotrophic effect and the potentiation of depolarization-induced increase of [Ca2+]i caused by activin were completely abolished by the protein synthesis inhibitor cycloheximide. These results suggest that activin supports neuronal survival by increasing the expression of voltage-dependent Ca2+ channel through the action of a tyrosine kinase and of protein kinase C, but not of Ca2+/calmodulin kinase.

Macrophage activation and migration in interface tissue around loosening total hip arthroplasty components

The bone-cement interface tissue of failed total hip arthroplasty (THA) has inflammatory characteristics, such as the presence of prostaglandin E2 and interleukin 1 (IL-1). We considered that the bone-cement interface tissue could be the site of granulomatous inflammation caused by a foreign-body reaction. It has been demonstrated that inflammatory cytokines and chemokines have an important role in granulomatous inflammation. Bone-cement interface tissue was obtained at revision from nine patients with failed cemented THA, and the role of macrophages was assessed by immunohistochemistry, electron microscopy, and molecular biological techniques. We used the reverse-transcriptional polymerase chain reaction to examine the expression of mRNA for IL-1 alpha, IL-1 beta, tumor necrosis factor alpha (TNF alpha), macrophage inflammatory protein (MIP)-1 alpha, MIP-1 beta, IL-8, and monocyte chemoattractant protein. Polyethylene debris surrounded by macrophages and phagocytosis of debris by macrophages was frequently observed in the interface tissue. Macrophage activation and the production of inflammatory cytokines such as IL-1 and TNF alpha might induce the development of interface tissue. Expression of chemokine mRNAs was also commonly seen, suggesting that this led to recruitment of macrophages into the bone-cement interface tissue. Debris released from implants appears to cause activation of macrophages and the production of inflammatory cytokines and chemokines that induce cellular recruitment into interface tissue. This mechanism might form a vicious cycle that aggravates THA loosening.

Decreased expression of the p16/MTS1 gene without mutation is frequent in human urinary bladder carcinomas

The p16 (CDKN2,MTS1) gene is located at 9p21 and its product, p16, inhibits the cyclin D/CDK4 complex. Loss of heterozygosity on chromosome 9p is very common in human bladder carcinomas and has been found in all stages of lesions, suggesting that it occurs early in bladder tumor progression. Several studies have revealed frequent homozygous deletion of the p16 gene in cell lines, and that such deletions are also common in some types of cancers. In addition, point mutations in the p16 gene have been identified in several types of neoplasia. In the present examination of urinary bladder tumors, no p16 gene mutations were detected, but nine cases out of 23 (39%) showed decreased mRNA expression, revealed by the reverse transcriptase polymerase chain reaction. There were no histological differences apparent between those cases with normal and those with decreased p16 expression. These results indicate that while p16 gene mutations may be rare, changes in the level of the p16 transcripts could play a role in human bladder carcinoma development.

Demonstration of ras and p53 gene mutations in carcinomas in the forestomach and intestine and soft tissue sarcomas induced by N-methyl-N-nitrosourea in the rat

The presence of ras family and p53 gene mutations in rat forestomach, intestine and liver tumors and soft tissue sarcomas induced by N-methyl-N-nitrosourea (MNU) was examined using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) followed by direct sequencing analysis. In the forestomach squamous cell carcinomas (SCC), Ha-ras and p53 mutations were detected in 2 (40%) and 4 (80%) of 5 cases, respectively. The figures for Ki-ras and p53 gene mutations in adenocarcinomas of the large and small intestines were 3 (18.8%) and 5 (31.3%) of 16 cases. Soft tissue sarcomas in different sites were found to have mutations of Ki-ras in 7 (23.3%) and of p53 in 9 (30%) of 30 cases. One forestomach SCC and 2 soft tissue sarcomas had double p53 mutations in different exons. Single cases of forestomach SCC and intestinal adenocarcinoma had mutations in both Ki-ras and p53 genes. No mutations were found in counterpart benign tumors or hepatocellular adenomas. The p53 mutation spectrum revealed preferential clustering within exon 8 for the forestomach SCCs, and exons 5 and 8 for the intestinal adenocarcinomas, whereas the distribution was evenly spread through exons 5 to 8 in soft tissue sarcomas. All the detected ras or p53 mutations were G:C to A:T transitions. These results indicate firstly that specific Ki-ras, Ha-ras and p53 gene mutations in MNU-induced lesions are related to particular alkylation sites (G:C to A:T transitions) and secondly, although not essential, Ki-ras, Ha-ras or p53 gene mutations may be involved in the progression stage of forestomach, intestine and soft tissue neoplasms induced by MNU.

Inhibitory effects of docosahexaenoic acid on colon carcinoma 26 metastasis to the lung

Unsaturated fatty acids, including n-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (C22:6, DHA) and eicosapentaenoic acid (C20:5, EPA), and a series of n-6 PUFAs were investigated for their anti-tumour and antimetastatic effects in a subcutaneous (s.c.) implanted highly metastatic colon carcinoma 26 (Co 26Lu) model. EPA and DHA exerted significant inhibitory effects on tumour growth at the implantation site and significantly decreased the numbers of lung metastatic nodules. Oleic acid also significantly inhibited lung metastatic nodules. Treatment with arachidonic acid showed a tendency for reduction in colonization. However, treatment with high doses of fatty acids, especially linoleic acid, increased the numbers of lung metastatic nodules. DHA and EPA only inhibited lung colonizations when administered together with the tumour cells, suggesting that their incorporation is necessary for an influence to be exerted. Chromatography confirmed that contents of fatty acids in both tumour tissues and plasma were indeed affected by the treatments. Tumour cells pretreated with fatty acids in vivo, in particular DHA, also showed a low potential for lung colony formation when transferred to new hosts. Thus, DHA treatment exerted marked antimetastatic activity associated with pronounced change in the fatty acid component of tumour cells. The results indicate that uptake of DHA into tumour cells results in altered tumour cell membrane characteristics and a decreased ability to metastasize.

Triazine derivatives inhibit rat hepatocarcinogenesis but do not enhance gap junctional intercellular communication

We report here novel candidate chemopreventive agents active against experimental hepatocarcinogenesis. The triazine derivatives 6-(2-chlorophenyl)-2,4-diamino-1,3,5-triazine (2CPDAT), 6-(3-chlorophenyl)-2,4-diamino-1,3,5-triazine (3CPDAT), 6-(4-chlorophenyl)-2,4-diamino-1,3,5-triazine (4CPDAT), 6-(4-pyridyl)-2,4-diamino-1,3,5-triazine (PyDAT), and 6-(pyridine N-oxid-4-yl)-2,4-diamino-1,3,5-triazine (PyNODAT), synthesized in our laboratory, in addition to 6-(2,5-dichloro-phenyl)-2,4-diamino-1,3,5-triazine (DCPDAT), or irsogladine, which is a widely used anti-ulcer drug, were investigated for potential chemopreventive effects in a rat liver medium-term bioassay system. A significant inhibitory influence on enzyme-altered liver foci was found for 2CPDAT, 3CPDAT, 4CPDAT, and PyNODAT, but not for DCPDAT or PyDAT. The involvement of gap junctional intercellular communication in the inhibition was studied, but no change in gap junctional intercellular communication capacity in rat liver cells in vitro or in gap junction protein (connexin 32) expression in rat liver in vivo was noted. These results indicate that, although these irsogladine analogues exert inhibitory effects on rat liver carcinogenesis, their action is independent of modification of gap junctional intercellular communication.

mRNA expression of matrix metalloproteinases and tissue inhibitors of metalloproteinase in interface tissue around implants in loosening total hip arthroplasty

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) play an important role in tissue destruction and remodeling. Nine samples of cement interface tissues from nine patients who had failed cemented total hip arthroplasty (THA) were obtained for revision of THA and analyzed on mRNA expression of MMPs and TIMPs. The preoperative serial radiographic examinations revealed an apparent clear zone around all implants. We excluded septic loosening as one of the factors affecting THA. Three samples were obtained from three different sites of the acetabular interface tissue in each patient. After extraction of total RNA from 27 samples, we used the reverse-transcriptional polymerase chain reaction (RT-PCR). mRNA of MMP-1, -2, -3, -9, and TIMP-1 and -2 was detected in the interface tissue. MMP-10 mRNA was not detected, yet MMP-1 and MMP-3 mRNA were commonly observed. TIMP-2 mRNA was also strongly expressed compared to TIMP-1. It was thus demonstrated that MMPs and TIMPs were produced locally in the cemented tissue of THA loosening. These findings may suggest that MMPs and TIMPs expressed around the implants play a critical role in the progression of aseptic loosening of THA.

Decreased connexin32 and a characteristic enzyme phenotype in clofibrate-induced preneoplastic lesions not shared with spontaneously occurring lesions in the rat liver

Two different types of focal preneoplastic lesions, tentatively named Type I and II lesions, were recognized in the liver of rats chronically treated with clofibrate for 104 weeks. Type I lesions were characterized by mostly negative glucose-6-phosphate dehydrogenase (G6PD) activity (6 out of 10, 60%) and positive expression of succinate dehydrogenase (10 out of 10, 100%), in addition to the previously documented complete lack of expression of glutathione S-transferase, placental form (GST-P) and gamma-glutamyl transpeptidase (GGT). Furthermore, most importantly, Type I lesions exhibited a clear decrease in immunohistochemically demonstrated connexin32 (Cx32) spot counts on their hepatocyte membranes, similarly to nitrosamine-induced lesions. In contrast, Type II lesions, mostly small in size and positively expressing GST-P and/or GGT and G6PD, similarly to their previously reported nitrosamine-induced counterparts, did not exhibit a significant decrease in Cx32 count. In addition, spontaneously occurring lesions, again sharing the same enzyme phenotype, did not show a decrease in Cx32. The results indicate that: (i) a clear distinction between the two lesions, with Type I being involved in clofibrate-induced tumors and Type II being more likely to be spontaneous in nature; (ii) a decrease in Cx32 is closely linked to lesion development and possibly stage of progression, irrespective of the enzyme phenotype and the applied carcinogen; (iii) the unaltered condition of Cx32 may suggest a slow growing or non-progressive nature.

Decreased levels of 2-amino-3-methylimidazo[4,5-f]quinoline-DNA adducts in rats treated with beta-carotene, alpha-tocopherol and freeze-dried aloe

To assess mechanisms of chemoprevention of hepatocarcinogenesis by trans-beta-carotene (beta-C), DL-alpha-tocopherol (alpha-T), and freeze-dried whole leaves of Kidachi aloe (Aloe), formation of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ)-DNA adducts was measured by 32P-post-labeling analysis, and CYP1A1 and CYP1A2 protein levels were analyzed by ELISA. Group 1 rats were fed diet containing 0.02% beta-C, 1.5% alpha-T or 30% Aloe over an 8-day period, while group 2 was given basal diet alone. On day 7, all animals were subjected to two-thirds partial hepatectomy (PH). Twelve hours after PH, they received a single dose of the carcinogenic food pyrolysate IQ (100 mg/kg) intragastrically, to initiate hepatocarcinogenesis. Rats were killed 6, 12, 24 and 48 h after IQ administration. The levels of adducts, expressed as relative adduct labeling values in rats treated with beta-C, alpha-T and Aloe, were decreased as compared with the control group at hour 24 (36 h after PH), with a significant difference in the case of the beta-C group (46.4% of the control value). Similarly, all showed a tendency for decrease at hour 48. Furthermore, the levels of CYP1A2, known to be responsible for activation of IQ, showed a significant reduction at hour 24. It is concluded that beta-C, and possibly also alpha-T and Aloe, have the potential to reduce IQ-DNA adduct formation, presumably as a result of decreased formation of active metabolites. The results may explain, at least in part, the previously observed inhibitory effects of these compounds on induction of preneoplastic hepatocellular lesions.

Clofibrate-induced neoplastic development in the rat liver is associated with decreased connexin 32 expression but not with a co-ordinated shift in expression of marker enzymes

Altered enzyme phenotype and expression of connexin 32 (Cx32), a gap junction protein were studied during the development of rat liver tumors induced by the non-genotoxic carcinogen, clofibrate. (1) In contrast to previous findings for nitrosamine-induced lesions, preneoplastic enzyme-altered foci (EAF) and neoplastic nodules (NN) lacked any clear association with degree of altered enzyme expression because of an almost complete negativity for GST-P and GGT. (2) Immunohistochemically demonstrated Cx32 spots on the hepatocyte membranes showed a clear decrease in clofibrate-induced lesions. (3) Naturally occurring EAF demonstrating GST-P and/or GGT positivity did not show a significant decrease of Cx32 counts suggesting a reversible nature. Therefore, the Cx32 decrease appears closely linked to progression of hepatocarcinogenesis irrespective of the enzyme phenotype of neoplastic focal lesions and the carcinogens used for their induction.

Cell proliferation and advancement of hepatocarcinogenesis in the rat are associated with a decrease in connexin 32 expression

The expression of connexin 32 (Cx32), a major liver gap junction protein, after partial hepatectomy (PH) and during development and progression of hepatocarcinogenesis was studied in the rat. Cx32 was quantitatively analyzed by counting immunohistochemically demonstrated protein spots on the membranes of hepatocytes. Livers were sequentially examined after PH to assess the correlation with cell proliferation. For the analysis of different stages in carcinogenesis, Cx32 was assayed in N-ethyl-N-hydroxyethylnitrosamine-induced enzyme altered foci (EAF), hyperplastic nodules (HN), hepatocellular carcinomas (HCC), pulmonary metastatic HCC and transplanted HCC in relation to their degree of altered enzyme expression. Cx32 showed: (i) a rapid decrease after PH to its lowest levels during and 12 h after the S phase of cell proliferation when 5-bromo-2'-deoxyuridine (BrdU) labeling indices were examined; (ii) a progressive decrease from early preneoplasia EAF to HN and HCC, values for pulmonary metastatic and transplanted HCC being 0; (iii) clearly inverse correlations with increased BrdU index and degree of altered enzyme expression in HN, indicating that these, with the lowest Cx32 count, are closest to HCC. Therefore, the observed decrease appears linked to cell proliferation and progression of hepatocarcinogenesis, providing a reflection of cellular independence and growth advantage.

Chemopreventive effects of beta-carotene, alpha-tocopherol and five naturally occurring antioxidants on initiation of hepatocarcinogenesis by 2-amino-3-methylimidazo[4,5-f]quinoline in the rat

Inhibitory effects of naturally occurring antioxidants on the initiation stage of hepatocarcinogenesis were studied. Group 1 rats were given a diet containing beta-carotene (beta-CT, 0.02%), alpha-tocopherol (alpha-TP, 1.5%), glutathione (GLT, 5%), vanillin (VNL, 1%), quercetin (QCT, 1%) or ellagic acid (ELA, 1%), or 3 doses of diallyl sulfide (DAS, 200 mg/kg, i.g.) over an 8-day period. On day 7, the animals received a single dose of 2-amino-3-methylimidazo[4,5-f] quinoline (IQ, 100 mg/kg, i.g.), 12 h after two-thirds partial hepatectomy for initiation and 2 weeks thereafter, were placed on promotion regimen comprising phenobarbital (0.05% in diet) and a single dose of D-galactosamine (100 mg/kg, i.p.). Groups 2 and 3 were treated as described for Group 1, but without test material or IQ, respectively. Survivors were killed at week 11 and antioxidant influence was assessed by comparing values for preneoplastic glutathione S-transferase placental form-positive (GST-P+) foci between Groups 1 and 2. All lesions larger than 70 microns in diameter consisting of approximately 5 cells in cross section were counted. Numbers of GST-P+ foci/cm2 in Group 1 were: beta-CT, 7.99; alpha-TP, 8.21; GLT, 9.71; DAS, 10.37; VNL, 10.57; QCT, 11.1; ELA, 12.5 (n = 11-15). All, except ELA, showed a significant decrease as compared with the Group 2 value of 14.54 (n = 15). Only beta-CT showed a significant decrease for the area value. This is the first report to show that beta-CT, alpha-TP, GLT, DAS, VNL, QCT exert inhibitory effects on initiation of hepatocarcinogenesis by the food carcinogen IQ, suggesting that these antioxidants might find application as chemopreventive agents. Furthermore, the current protocol proved practical for the assessment of chemopreventive agents within 11 weeks, a relatively short period.