Single tunnel technique versus coracoid sling technique for arthroscopic treatment of acute acromioclavicular joint dislocation.

To evaluate and compare the efficacy of two techniques for the treatment of acute acromioclavicular joint dislocation, the charts of 60 patients diagnosed with acute Rockwood type IV and V acromioclavicular joint dislocation that undergone arthroscopic fixation procedure with single tunnel technique (N = 30, 30.7 ± 5.7 years old) or coracoid sling technique (N = 30, 30.1 ± 5.4 years old) fixation were retrospectively reviewed. The Visual Analog Scale pain score, Constant shoulder functionality score, Karlsson acromioclavicular joint score, the time of return to sports and activity, and plain radiographs of the affected shoulder at different time points of follow-up were recorded for a minimum of 2 years post-op. The majority of the patients recovered to their preoperative activity levels with few complications. The average postoperative acromioclavicular and coracoclavicular distances were significantly narrower than preoperative measurements in both groups without significant difference between the two groups at 2 years post-op (P < 0.05). The coracoid sling technique group had reduced operative time, shorter time of recovery of shoulder movements, higher Constant functionality scores and Karlsson acromioclavicular joint scores, and fewer complications than the single tunnel technique group at the last follow-up (P < 0.05). Therefore, coracoid sling technique achieved superior clinical outcomes with fewer complications compared to the traditional single tunnel technique in arthroscopic treatment of acute acromioclavicular joint dislocation.

[Clinical outcomes of hip arthroscopic treatment for femoroacetabular impingement:a comparative study between Inside-out and Outside-in approach].

OBJECTIVE: To compare the clinical outcomes and complications of hip arthroscopic treatment for femoroacetabular impingement (FAI) performed with either Inside-out or Outside-in approach. METHODS: The clinical date of 48 patients with FAI treated by hip arthroscopy surgery and follow-up from June 2016 to June 2019 were retrospectively analyzed. According to the different operative methods, the patients were divided into two groups. Inside-out group, from central compartment to peripheral compartment;Outside-in group, from peripheral compartment to central compartment. There were 14 males and 10 females in Inside-out group with an averageage of (39.8±7.6)years old, 13 males and 11 females in Inside-out group with an average age of (39.5±9.1)years old in Outside-in group. There was no significant difference in age, gender, body mass index, side, impingement type, medical history and follow-up time between the two groups. The complication occurrence rate, modified Harris hip score (mHHS)and nonarthritic hip score (NAHS) were compared between these two groups. RESULTS: The mHHs and NAHS scores of the two groups were significantly higher than those before operation, but there was no significant difference between the two groups (P>0.05). In the Inside-out group, there were 4 cases of nerve traction injury and 3 cases of iatrogenic injury, while only 1 case of nerve traction injury occurred in the Outside-in group. The incidence of complications in the inside out group was higher than that in the outside in group (16.7% vs 4.2%, χ2=5.400, P=0.020). CONCLUSION: Both hip arthroscopic surgery methods can obtain satisfactory clinical efficacy in the treatment of FAI, but the incidence of postoperative complications of Outside-in surgical method is lower. The out-side in method can be preferentially selected for the patients with the indications of operation.

Association between hip and knee osteoarthritis with falls: A systematic review and meta-analysis.

OBJECTIVE: To examine the association between hip and knee osteoarthritis (OA) and falls. Potentially relevant articles that examine the association between hip, knee, radiological, and self-reported OA and falls were retrieved from PubMed, EMBASE, Scopus, and Web of Science up until March of 2020. METHODS: The pooled risk ratios (RRs) as well as their related 95% confidence intervals (CIs) were calculated. Statistic and subgroup analyses were performed. A total of 21 studies involving 146 965 participants were included. RESULTS: No association was found between hip OA and falls. The pooled RRs value suggested a higher prevalence of falls in knee OA patients (RR = 1.35, 95% CI: 1.20 to 1.51, P < .00001) and self-reported OA (RR = 1.33, 95% CI: 1.23 to 1.45, P < .00001) than in non-OA subjects. The pooled RR value suggested no difference between prevalence of falls in radiological OA patients compared to non-OA subjects (RR = 1.82, 95% CI: 0.89 to 3.73, P = .10). Both radiological and self-reported knee OA seem to be positively associated with falls, while no obvious association was found between hip OA and falls. CONCLUSIONS: Therefore, knee OA is a risk factor for falls which should be closely monitored.

Interbundle Impingement Pressure in Individualized and Nonindividualized Double-Bundle Anterior Cruciate Ligament Reconstruction: A Cadaveric Study.

BACKGROUND: Graft impingement is one of the main concerns in double-bundle anterior cruciate ligament reconstruction (DB-ACLR). Impingement between the anteromedial (AM) and posterolateral (PL) bundles has been postulated to cause graft deterioration or rerupture, but this has not been thoroughly investigated, and the interbundle impingement pressure (IIP) has not been well researched. PURPOSE: To determine the IIP between the AM and PL bundles in the native anterior cruciate ligament (ACL) and in DB-ACLR with individualized and nonindividualized double-tunnel placement. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 30 fresh-frozen, nonpaired, human cadaveric knees were randomly divided into 3 groups of 10 knees: native intact ACL (NI group), DB-ACLR tunnel placement using the preserved remnant procedure (individualized reconstruction) (PR group), and DB-ACLR tunnel placement using the bony landmark procedure (nonindividualized reconstruction) (BL group). Pressure sensors were inserted between the AM and PL bundles. The knee was moved passively from full extension to full flexion, and the IIP between the 2 ACL bundles was measured every 15°. Similarly, the impingement pressure was measured between the ACL and intercondylar roof and between the ACL and posterior cruciate ligament (PCL). RESULTS: No significant differences were found in the maximum, mean, or minimum ACL-roof and ACL-PCL impingement pressures among the 3 groups. The IIP significantly increased when the knee joint was flexed >120° in all 3 groups (P < .001). Compared with the other 2 groups, the BL group had significantly higher maximum and mean IIP throughout the range of knee movement (P < .001) and from maximum extension to 120° of flexion (P < .001). The BL group also had significantly higher minimum IIP than the other 2 groups when knee flexion was >120° (P < .001). No significant differences were seen in maximum, minimum, or mean IIP between the NI and PR groups. CONCLUSION: The PR procedure (individualized DB-ACLR) was more consistent with the interbundle biomechanical conditions of the native ACL, whereas the BL procedure (nonindividualized DB-ACLR) had higher maximum and mean IIP. The IIP was higher than the ACL-intercondylar roof or ACL-PCL pressures, and it increased significantly when knee flexion was >120°. CLINICAL RELEVANCE: These data suggest that surgeons can perform individualized DB-ACLR using preserved remnants for tunnel placement as impingement-free DB-ACLR.

Arthroscopic repair of the medium-size rotator cuff tear with the novel technique of the point union bridge: a minimum 2-year follow-up cohort study.

BACKGROUND: Achieving secure fixation and preventing retear have been recognized as fundamental in arthroscopic repair of rotator cuff tears. Moreover, reducing internal implantation can lower medical expenses and minimize the operation time, which is essential for the surgical safety and postoperative rehabilitation of the patients. We have recently proposed the point union bridge (PUB) suture configuration as a novel method for not only providing equivalent fixation but also decreasing the operation time and medical expenses. However, no comparative clinical studies have been performed. METHODS: From March 2014 to September 2016, a total of 88 patients with diagnoses of medium-size rotator cuff tears underwent arthroscopic repair with a randomly assigned technique-either the PUB technique (n = 42) or the double-row suture bridge (DRSB) technique (n = 46). All patients underwent a minimal 2-year follow-up. We used the Constant-Murley score (CMS), American Shoulder and Elbow Surgeons (ASES) score, active and passive range of motion, and visual pain-simulation score (visual analog scale [VAS] score) to assess the functional outcomes. In addition, we recorded the arthroscopic operation time, medical costs, and postoperative complications. All patients received magnetic resonance imaging at the 6-month and 2-year postoperative evaluations to assess structural integrity and tendon healing. RESULTS: At the 2-year follow-up, all scoring parameters evaluated (CMS, ASES score, and VAS score), as well as active and passive range of motion, improved significantly in both groups as compared with preoperative assessments. The PUB technique significantly decreased the operation time (55.9 ± 14.1 minutes vs. 72.2 ± 14.2 minutes for PUB vs. DRSB, P < .001) and medical expenses ($2608.0 ± $391.1 vs. $4056.9 ± $350.9 for PUB vs. DRSB, P < .001). However, no significant differences between the 2 techniques were found in any functional assessments of the shoulder (CMS, ASES score, and VAS score), repair integrity, or the retear rate at the 2-year follow-up. CONCLUSION: Arthroscopic repair of the medium-size rotator cuff tear with either the PUB or DRSB technique could yield both satisfactory improvements in the shoulder function of patients and equivalent tendon integrity. With less consumption of internal implants, the PUB technique significantly reduced the operation time and decreased medical expenses.

A retrospective study to compare the clinical effects of individualized anatomic single- and double-bundle anterior cruciate ligament reconstruction surgery.

To evaluate the clinical efficacy of single- and double- bundle individualized anatomic anterior cruciate ligament (ACL) reconstruction, we retrospectively analyzed the data and charts of 920 patients with ACL rupture who received individualized anatomic ACL reconstruction surgery at our center. All of the patients underwent arthroscopic ACL reconstruction with autologous hamstring tendons. The patients were divided into two groups: the single-bundle individualized anatomic reconstruction group (N = 539), and the double-bundle individualized anatomic reconstruction group (N = 381). The IKDC, Lysholm and Tegner scores were used to subjectively evaluate the function of the knee joint during the postoperative follow-up. The Lachman test, pivot shift test and KT-3000 were used to objectively evaluate the stability of the knee. All 920 patients participated in clinical follow-up (average duration: 27.91 ± 3.61 months) achieved satisfied outcomes with few complications. The postoperative IKDC, Lysholm and Tegner scores, and the objective evaluation of knee joint stability were significantly improved compared to the preoperative status in both groups (P < 0.05). No statistically significant difference was observed between the two groups at the final follow-up (P > 0.05). Therefore, no difference in terms of the IKDC, Lysholm and Tegner score, or KT-3000 was observed between the individualized anatomic single- and double-bundle ACL reconstruction techniques. Both techniques can be used to restore the stability and functionality of the knee joint with satisfactory short-term efficacy.

The time-dependent effects of bipolar radiofrequency energy on bovine articular cartilage.

PURPOSE: The purpose of this study was to compare the effect of bipolar radiofrequency energy (bRFE) on chondroplasty at the different time durations in an in vitro experiment that simulated an arthroscopic procedure. METHODS: Six fresh bovine knees were used in our study. Six squares were marked on both the medical and lateral femoral condyles of each femur. Each square was respectively treated with bRFE for 0 s, 10 s, 20 s, 30 s, 40 s and 50 s. Full-thickness articular cartilage specimens were harvested from the treatment areas. Each specimen was divided into three distinct parts: one for hematoxylin/eosin staining histology, another for cartilage surface contouring assessment via scanning electron microscopy (SEM), and the last one for glycosaminoglycan (GAG) content measurement. RESULTS: bRFE caused time-correlated damage to chondrocytes, and GAG content in the cartilage was negatively correlated to exposure time. bRFE caused time-correlated damage to chondrocytes. The GAG content in the cartilage negatively correlated with the exposure time. The sealing effect positively correlated with the exposure time. Additionally, it took at least 20 s of radiofrequency exposure to render a smooth cartilage surface and a score of 2 (normal) in the scoring system used. CONCLUSION: bRFE usage in chondroplasty could effectively trim and polish the cartilage lesion area; however, it induces a dose-dependent detrimental effect on chondrocytes and metabolic activity that negatively correlated with the treatment time. Therefore, cautions should be taken in the use of bRFE for treatment of articular cartilage injury.

Modified Arthroscopic Latarjet Procedure: Suture-Button Fixation Achieves Excellent Remodeling at 3-Year Follow-up.

BACKGROUND: Some studies have advocated the use of suture-button fixation during the Latarjet procedure to reduce complications associated with screw fixation. However, the sample size of these studies is relatively small, and their follow-up period is short. PURPOSE: To investigate the efficacy of the suture-button Latarjet procedure with at least 3 years of follow-up and remodeling of the coracoid graft. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 152 patients who underwent the suture-button Latarjet procedure between February 2013 and February 2016 were selected, and 128 patients who met the inclusion criteria were enrolled in this study. Preoperative and postoperative clinical results were assessed. The position and healing condition of the coracoid graft and arthropathy of the glenoid and humeral head were also assessed using radiography and 3-dimensional computed tomography (CT). RESULTS: The mean follow-up time was 40.3 ± 5.8 months. There were 102 patients included in this study. The mean visual analog scale score for pain during motion, the American Shoulder and Elbow Surgeons score, the Rowe score, and the Walch-Duplay score were improved considerably. A total of 100 grafts achieved bone union. The overall absorption rate was 12.6% ± 4.3%. Graft absorption mostly occurred on the edge and outside the "best-fit" circle of the glenoid. A vertical position was achieved in 98 grafts (96% of all cases) immediately postoperatively, with the mean graft midline center at the 4 o'clock position. In the axial view, CT showed that 89 grafts were flush to the glenoid, whereas 2 and 11 grafts were fixed medially and laterally, respectively. In all cases, the bone graft and glenoid tended to extend toward each other to form concentric circles during the remodeling process. During follow-up observations, the height of the 11 grafts that were positioned laterally (ie, above the glenoid level) exhibited a wave-curved change. No arthropathy was observed in any patient. CONCLUSION: Patient outcomes were satisfactory after the modified arthroscopic suture-button Latarjet technique. Graft absorption mostly occurred on the edge and outside the "best-fit" circle of the glenoid. The graft exhibited the phenomenon of ectatic growing when it fused with the glenoid and finally remodeled to a new concentric circle with the humeral head analogous to the original glenoid. Grafts positioned laterally did not cause arthropathy of the joints within the period of the study.

A pilot study of blood supply of the coracoid process and the coracoid bone graft after Latarjet osteotomy.

Latarjet osteotomy is still one of the most reliable and commonly used surgeries in treating recurrent anterior shoulder dislocation. The coracoid process (CP) is the main structure of this surgery. However, the blood supply of CP is not fully understood, and the extent of destruction of blood supply of coracoid bone graft after Latarjet osteotomy procedure is still controversial. Five embalmed cadaveric upper limbs specimens were employed for macro observation of the blood supply of CP. The conjoint tendon (CT) and CP interface were dissected for histology. Sixteen fresh frozen shoulder specimens were used for perfusion and micro CT scanning. Eight specimens were used to present the whole vessel structure of CP. The other eight underwent Latarjet osteotomy procedure. The coracoid bone grafts in both groups were scanned to clarify the remnant blood supply. It was found that the CP was nourished by supra-scapular artery (SSA), thoracic-acromial artery and branch from second portion of the axillary artery (AA). After Latarjet osteotomy procedure, no artery from CT was detected to penetrate the CP at its attachment. Only in one specimen the blood vessel that originated from the CT penetrated the bone graft at the inferior side. Therefore, most of the blood supply was destroyed although there is a subtle possibility that the vessels derived from the CT nourished the inferior side of the CP. In a nutshell, CP is a structure with rich blood supply. The traditional Latarjet osteotomy procedure would inevitably cut off the blood supply of the coracoid bone graft.

[Effect of isokinetic training of thigh muscle group on graft remodeling after anterior cruciate ligament reconstruction].

OBJECTIVE: To investigate the effect of isokinetic training of thigh muscle group on graft remodeling after anterior cruciate ligament (ACL) reconstruction, and summarize the relevant rules to guide the clinic. METHODS: Between August 2016 and December 2016, forty patients underwent arthroscopic ACL reconstruction using hamstring tendon were randomly divided into isokinetic group and control group ( n=20). The two groups of patients underwent staged rehabilitation treatment. The isokinetic group replaced the traditional intervention with the corresponding isokinetic strength training from 3 to 6 months after operation, and the traditional rehabilitation intervention was used in the control group. Finally, 12 cases of isokinetic group and 12 cases of control group with complete follow-up were enrolled in study. There was no significant difference in gender, age, body mass index, side of injury, the interval between injury and operation, and preoperative International Knee Documentation Committee (IKDC) score between the two groups ( P>0.05). The peak torque (PT) of knee extension and flexion and hamstring quadriceps ratio (H/Q) were measured at 3 months, 6 months, 12 months, and the second-look arthroscopy. The MRI examination was performed at the same time to evaluate graft remodeling. The shape, tension, and degree of vascularization of grafts were observed under arthroscopy. The grafts were harvested and observed by HE staining. RESULTS: The invertal between ACL reconstruction and the second-look arthroscopy was (23.57±3.23) months in isokinetic group and (23.22±3.56) months in control group, showing no significant difference between the two groups ( P>0.05). At the second-look arthroscopy, the IKDC score was 90.45±4.73 in isokinetic group and 89.32±4.54 in control group, showing significant differences when compared with preoperative scores in the two groups ( P<0.05). But there was no significant difference between the two groups ( t=0.868， P=0.404). At 3 months after operation, there was no significant difference in the PT of knee extension and flexion between the two groups ( P>0.05). At 6 months, 12 months, and the second-look arthroscopy, the PT of knee extension and flexion in isokinetic group were higher than those in control group ( P<0.05). The H/Q at 6 months and 12 months were higher in isokinetic group than in control group, and the differences were significant ( P<0.05). There was no significant difference in MRI score between the two groups at 3 months, 6 months, and the second-look arthroscopy ( P>0.05). The MRI score at 12 months was significantly higher in isokinetic group than in control group ( P<0.05). At the second-look arthroscopy, there was no significant difference in the arthroscopic score between the two groups ( P>0.05), and the histological score of the isokinetic group was superior to the control group ( P<0.05). CONCLUSION: On the basis of regular rehabilitation training, using the isokinetic training system to develop a suitable post-surgical isokinetic rehabilitation training program is helpful in early muscle strength recovery, early graft remodeling, and even long-term histological results after ACL reconstruction.

[A correlation study between the Mohawk expression level and the collagen fiber diameter of hamstring tendon graft after anterior cruciate ligament reconstruction].

OBJECTIVE: To evaluate the correlation between the Mohawk (MKX) expression level and the collagen fiber diameter of autologous hamstring tendon graft during the stable graft remodeling phase after anterior cruciate ligament (ACL) reconstruction. METHODS: Between January 2018 and August 2018, patients who underwent arth-roscopic single-bundle anatomical ACL reconstruction with autologous hamstring tendons for at least 48 months and also underwent second-look arthroscopy were enrolled in study. During the second-look arthroscopic procedures, ACL graft biopsies were performed from the surface of central part of the ligament. MKX expressions of ACL grafts were analysed by real-time fluorescent quantitative PCR (qRT-PCR). The ultrastructure of collagen fibers of grafts were evaluated by transmission electron microscopy, which included average diameter of collagen fibers (D c), average diameter of large-diameter collagen fibers (D L), average diameter of small-diameter collagen fibers (D S), and large-small collagen fibers ratio (R L/S). The correlation between MKX expression level and graft collagen fiber diameter was calculated. RESULTS: Twenty-six patients met the selection criteria and their ACL graft specimens were enrolled in the study. The interval between ACL reconstruction and second-look arthroscopy was 52-128 months, with an average of 78.6 months. Arthroscopic graft remodeling score was 3-6 (mean, 4.8). There were 17 cases of excellent remodeling and 9 cases of fair remodeling. All ACL grafts showed typical bimodal distributions of both large-diameter collagen fibers and small-diameter collagen fibers, but the ultrastructural characteristics of the graft collagen fibers were different according to different remodeling status under arthroscopy. The D C, D L, D S, and R L/S of the graft specimens were (65.2±9.3) nm, (91.6±10.5) nm, (45.7±8.6) nm, and 0.73±0.12, respectively. The relative expression level of MKX was 1.42±0.11, which was positively linearly correlated with D C, D L, and R L/S, and the correlation coefficient was statistically significant ( r=0.809, P=0.000; r=0.861, P=0.000; r=0.942, P=0.000), while there was no significant correlation between D S and relative expression level of MKX ( r=0.147, P=0.238). Regression analysis showed that the relative expression level of MKX could predict the D C, D L, and R L/S results of the ACL graft specimens ( P<0.05). CONCLUSION: After autologous hamstring tendon grafts stepped into stabilized remodeling phase, MKX expression level could predict the diameter measurement results of collagen fibers and be used as an important evaluation basis for graft collagen anabolic metabolism.

Characterization of a novel polyvinyl alcohol/chitosan porous hydrogel combined with bone marrow mesenchymal stem cells and its application in articular cartilage repair.

BACKGROUND: Different substances are combined to compensate for each other's drawbacks and create an appropriate biomaterial. A novel Polyvinyl alcohol (PVA)/chitosan (CS) porous hydrogel was designed and applied to the treatment of osteochondral defects. METHODS: Hydrogels of various PVA/CS ratios were tested for physiochemical and mechanical properties in addition to cytotoxicity and biocompatibility. The hydrogels with the best PVA/CS ratio were used in the animal study. Osteochondral defects were created at the articular cartilage of 18 rabbits. They were assigned to different groups randomly (n = 6 per group): the osteochondral defect only group (control group), the osteochondral defect treated with hydrogel group (HG group), and the osteochondral defect treated with hydrogel loaded with bone marrow mesenchymal stem cells (BMSCs) group (HG-BMSCs group). The cartilage was collected for macro-observation and histological evaluation at 12 weeks after surgery. RESULTS: The Hydrogel with PVA/CS ratio of 6:4 exhibited the best mechanical properties; it also showed stable physical and chemical properties with porosity and over 90% water content. Furthermore, it demonstrated no cytotoxicity and was able to promote cell proliferation. The HG-BMSCs group achieved the best cartilage healing. CONCLUSIONS: The novel PVA/CS porous composite hydrogel could be a good candidate for a tissue engineering material in cartilage repair.

Clinical outcomes and radiologic assessment of a modified suture button arthroscopic Latarjet procedure.

BACKGROUND: As several neurologic and hardware complications have been reported with screw fixation. Suture buttons are used to serve as an alternative to screw fixation to obtain better outcome and to reduce the complication. The purpose of this study was to observe the clinical outcomes and make the radiologic assessment of a modified suture button (MSB) arthroscopic Latarjet procedure. METHODS: A total of ninty-one patients with recurrent shoulder joint dislocation who underwent MSB arthroscopic Latarjet procedure was retrospectively reviewed. Fifty cases identified from the chart review met the inclusion criteria. The clinical outcomes and position of the grafts, glenohumeral degeneration, and graft healing condition were assessed postoperatively in a follow-up with at least one and half of a year. RESULTS: All the fifty patients were satisfied with their clinical outcome. The overall complication rate was 4% in this study. The mean visual analog scale score, the affected shoulder active mobility in Ers(external rotation at the side), Era(external rotation in abduction) decreased significantly; the ASES score, Rowe score, Walch-Duplay score improved significantly. CT scans in the sagittal view showed that grafts in 88% of cases were in good position, grafts in 12% of cases were fixed too superiorly and inferiorly. In the axial view grafts in forty cases were flush with the glenoid rim, ten were considered as too lateral. The ten grafts became remodeled and were more flush with the glenoid rim in the follow-up. CONCLUSIONS: The MSB arthroscopic Latarjet procedure provides excellent outcome with few complications, and no degenerative changes were observed in the follow-up. Moreover, the graft fixed too laterally presented a phenomenon of remodeling and became flush with the glenoid rim over time.

A retrospective comparative study of arthroscopic fixation in acute Rockwood type IV acromioclavicular joint dislocation: single versus double paired Endobutton technique.

BACKGROUND: Rockwood type IV acromioclavicular joint (ACJ) dislocation is a trauma usually needs surgical treatment. Paired EndoButton technique (PET) is used in treating such condition. However, the effect of using different types of PET (single versus double PET) for fixation remains controversial. This study aims to evaluate and compare the efficacy of single and double PET and to provide a suitable option for the surgeons. METHODS: We retrospectively reviewed the charts of patients with acute Rockwood type IV ACJ dislocation who had undergone arthroscopic fixation using single or double PET fixation between March 2009 and March 2015. Seventy-eight consecutive patients identified from chart review were picked and were divided into the single and double PET group with 39 cases in each group. The indexes of visual analog scale score (VAS) for pain, the radiographs of the affected shoulder at different time points of the follow-up, the time of return to activities and sports, the constant functional score, and the Karlsson acromioclavicular joint (ACJ) score, were assessed in a minimum of 2 years postoperation. RESULTS: The average coracoclavicular (CC) and acromioclavicular (AC) distances of the affected joints in the double PET group were significantly smaller than those of the single PET group 2 years postoperation (P < 0.05). The average AC and CC distances in the healthy shoulder joints were significantly smaller than those of the affected joints in the single PET group (P < 0.05); however, these values were not significantly different from those of the affected joints in the double PET group (P > 0.05). The mean VAS pain score was not significantly different, while significant difference was found for the number and times of cases return to activities and sports, constant functional score, and Karlsson ACJ score (P < 0.05) between the two groups. Therefore, the double PET group has better outcome than the single PET group. Complications including redislocation, button slippage, erosion, or AC joint instability occurred in the single PET group, while the complication in the double PET group was rare. CONCLUSIONS: Compared with the single PET, the double PET group achieved better outcome with less complications in arthroscopically treating acute Rockwood type IV ACJ dislocation.

Arthroscopic reduction and fixation of coronoid fractures with an exchange rod-a new technique.

BACKGROUND: The ulnar coronoid process plays a central role in maintaining elbow stability. Some of its fractures were often combined with injury of bone and ligament. Arthroscopy enables perfect visualization to allow anatomical repair. METHODS: From January 2012 to December 2013, six patients (four males, two females) with a mean age of 26.6 years were treated. The left and right ulnas were involved in two and four patients, respectively. All patients suffered from ipsilateral subluxation of the elbow without associated radial fracture. According to the Regan and Morrey fracture classification and O'Driscoll's classification, two and four patients were classified as type I and type II and as having tip fracture (O'Driscoll type I) and anteromedial fracture (O'Driscoll type II), respectively. Exchange rod technology via the elbow front center approach was used for reduction and fixation of fractures of the coronoid process of the ulna. RESULTS: Intra- and postoperative X-ray examination showed that the fractures were satisfactorily fixed and that the screw and fracture line were vertical to each other. Follow-ups showed that the fractures had healed well, and the average elbow extension was -2° while the average flexion was 140°. No problems related to pronation or supination, elbow instability, or complications of blood vessels or nerves were reported. The elbows showed excellent results according to the Mayo Elbow Performance Score. CONCLUSIONS: Arthroscopy using an exchange rod can provide excellent visual exposure of the fractured joints, without the need for a large incision during the anatomical repair. Moreover, it protects the surrounding soft tissue, shows good stability of the components, and allows early rehabilitation exercises.

Repair of rabbit cartilage defect based on the fusion of rabbit bone marrow stromal cells and Nano-HA/PLLA composite material.

Objective To assess the effect of the fusion of rabbit bone marrow stromal cells (rBMSCs) and Nano-hydroxyapatite/poly (l-lactic acid) (Nano-HA/PLLA) in repairing the rabbit knee joint with full-thickness cartilage defect. Method The rBMSCs were isolated and cultured in vitro, and the third generation of rBMSCs was co-cultured with the Nano-HA/PLLA to construct the tissue-engineered cartilage (TEC). Eighteen New Zealand white rabbits were selected and randomly divided into three groups, namely, TEC group, Nano-HA/PLLA group, and control group. A cartilage defect model with the diameter of 4.5 mm and depth of 5 mm was constructed on the articular surface of medial malleolus of rabbit femur. General observation, histological observation, and Wakitani's histological scoring were conducted in the 12th and 24th week postoperatively. Results The results of TEC group indicated that new cartilage tissue was formed on the defect site and subchondral bone achieved physiological integration basically. Histological and immunohistochemical analyses indicated the generation of massive extracellular matrix. In contrast, limited regeneration and reconstruction of cartilage was achieved in the Nano-HA/PLLA group and control group, with a significant difference from the TEC group (p < 0.05). Moreover, the effect of cartilage repair was positively correlated with time. Conclusion The porous Nano-HA/PLLA combined with BMSCs promoted the repair of weight-bearing bone of adult rabbit's knee joint with cartilage defect.

DNA Methylation Profiling in Chondrocyte Dedifferentiation In Vitro.

DNA methylation has emerged as a crucial regulator of chondrocyte dedifferentiation, which severely compromises the outcome of autologous chondrocyte implantation (ACI) treatment for cartilage defects. However, the full-scale DNA methylation profiling in chondrocyte dedifferentiation remains to be determined. Here, we performed a genome-wide DNA methylation profiling of dedifferentiated chondrocytes in monolayer culture and chondrocytes treated with DNA methylation inhibitor 5-azacytidine (5-AzaC). This research revealed that the general methylation level of CpG was increased while the COL-1A1 promoter methylation level was decreased during the chondrocyte dedifferentiation. 5-AzaC could reduce general methylation levels and reverse the chondrocyte dedifferentiation. Surprisingly, the DNA methylation level of COL-1A1 promoter was increased after 5-AzaC treatment. The COL-1A1 expression level was increased while that of SOX-9 was decreased during the chondrocyte dedifferentiation. 5-AzaC treatment up-regulated the SOX-9 expression while down-regulated the COL-1A1 promoter activity and gene expression. Taken together, these results suggested that differential regulation of the DNA methylation level of cartilage-specific genes might contribute to the chondrocyte dedifferentiation. Thus, the epigenetic manipulation of these genes could be a potential strategy to counteract the chondrocyte dedifferentiation accompanying in vitro propagation. J. Cell. Physiol. 232: 1708-1716, 2017. © 2016 Wiley Periodicals, Inc.

Cytocompatibility of PLA/Nano-HA composites for interface fixation.

OBJECTIVE: When preliminary tests have confirmed a nano-hydroxyapatite (Nano-HA) content of 20% of the polylactic acid (PLA) composite material of Nano-HA interface fixation material for biomechanical requirements, there is a need for further observation of its biocompatibility and clinical applications, to provide reference data. METHODS: Preparation of Nano-HA content of 20% PLA composite Nano-HA bone substitute material and extract. The establishment of the negative control group (containing 10% fetal bovine serum in DMEM complete medium), experimental group (extract), the positive control group (mass concentration of 0.64% phenol), and a co-culture of rabbit bone marrow mesenchymal stem cells (rBMSC) and materials extraction liquid. Observation of the morphological changes in rBMSC in culture at time points of 3, 5, and 7 days, the use of the MTT assay, and determination of the relative growth in the above set of rBMSC in cell culture at 3, 5, and 7 days, to judge the material's cytotoxicity. RESULTS: With time, the absorbance value of the three groups of cells were significantly increased (P < 0.01). The relative growth of the rBMSCs in experimental group in the first 3, 5, and 7 days was 95.3%, 96.8% and 97.6%; the cytotoxicity was according to the national standards I; the difference was not significant (P > 0.05) between the the experimental group and the negative control group; there was a significant difference between the positive control group and the other 2 groups (P < 0.05). Cells in the experimental group were seen having normal morphology, and spindle-shaped adherent growth. CONCLUSION: PLA composite artificial bone materials and Nano-HA show good cell compatibility, and the values for cytotoxicity, with reference to GB/T16886.5.2003 (China) standards, are in the safe range.