Minimal tibial tunnel enlargement after anatomic rectangular tunnel anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft.

BACKGROUND: The purpose of this study was to evaluate the tibial tunnel enlargement after the anatomical rectangular tunnel (ART) anterior cruciate ligament reconstruction (ACLR) with a bone-patellar tendon-bone (BTB) graft and to elucidate the correlation between the enlargement and length of the tendinous portion inside the tibial tunnel. In addition, we aimed to analyze the correlation between patient characteristics and tibial tunnel enlargement. METHODS: This study included 50 patients who underwent ART ACLR. Lateral radiographs at the time of surgery and at 2 years were compared to evaluate the tibial tunnel enlargement. Subsequently, correlations between the tunnel enlargement and (1) length of tendinous portion inside the tibial tunnel or (2) characteristics of the patients, including anterior knee laxity measured by KT-1000 arthrometer, age, sex, height, body weight, and Tegner activity level scale, were analyzed. RESULTS: The tibial tunnel was enlarged by 2.6 ± 4.2% 2 years postoperatively. The length of the tendinous portion inside the tibial tunnel was 7.8 ± 4.9 mm. There was no significant correlation between tunnel enlargement and length of tendinous portion inside the tunnel. None of the patient characteristics were detected as a risk factor for tibial tunnel enlargement. CONCLUSIONS: (1) The postoperative tibial tunnel enlargement was minimum after ART ACLR with a BTB graft. (2) There was no correlation between tibial tunnel enlargement and length of tendinous portion of BTB graft inside the tunnel. (3) None of the patient characteristics were detected as a risk factor of the tibial tunnel enlargement.

On-lay grafting of a calcium hydroxyapatite bone substitute: A preliminary animal experimental study.

BACKGROUND: Bone substitutes are widely accepted for various clinical applications. However, the usage is predominantly intraosseous implantation, whereas extraosseous on-lay grafting is rare and lacks scientific evidence. The purpose of this study is to elucidate whether osteoconduction occurs in on-lay grafted bone substitute. METHODS: Custom-made interconnected porous calcium hydroxyapatite ceramic (IPCHA) was on-lay grafted with screw or anchor fixation (S- and A-groups, respectively) at the anterior aspect of the femur of skeletally mature Japanese white rabbits. At 3, 6 and 12 weeks postoperatively, 4 samples for each time point and each group were evaluated by microfocus computed tomography (micro-CT) and histology. RESULTS: Volume-rendered three-dimensional micro-CT images showed a high-density calcified area infiltrating IPCHA from the femoral cortex as of 6 weeks. When quantified, the calcified volume per unit volume first showed no difference between the two groups at 3 weeks but increased over time, and became significantly greater in the S-group than in the A-group (p = 0.012 and 0.004 at 6 and 12 weeks, respectively). Histologically, IPCHA pores were first occupied by fibrous tissue at 3 weeks; then, the pores adjacent to the femoral cortex were gradually replaced by bony tissue as of 6 weeks for both fixations. CONCLUSIONS: IPCHA allowed new bone formation inside the material even though it was implanted in an on-lay fashion on the cortical bone. Our results suggested that on-lay grafted IPCHA exerted its osteoconductivity well, with more new bone forming in screw-fixated samples than in anchor-fixated samples.

Anatomical rectangular tunnels identified with the arthroscopic landmarks result in excellent outcomes in ACL reconstruction with a BTB graft.

PURPOSE: To elucidate tunnel locations and clinical outcomes after anatomic rectangular tunnel (ART) anterior cruciate ligament reconstruction (ACLR) using a bone-patellar tendon-bone (BTB) graft. METHODS: Sixty-one patients with a primary unilateral ACL injury were included. Tunnels were created inside the ACL attachment areas after carefully removing the ACL remnant and clearly identifying the bony landmarks. Using 3-dimensional computed tomography (3-D CT) images, the proportion of the tunnel apertures to the anatomical attachment areas was evaluated at 3 weeks. The clinical outcomes were evaluated at 2 years postoperatively. RESULTS: Geographically, the 3-D CT evaluation showed the entire femoral tunnel aperture; at least 75% of the entire tibial tunnel aperture area was consistently located inside the anatomical attachment areas surrounded by the bony landmarks. In the International Knee Documentation Committee (IKDC) subjective assessment, all patients were classified as 'normal' or 'nearly normal'. The Lachman test and pivot-shift test were negative in 98.4% and 95.1% of patients, respectively. The mean side-to-side difference of the anterior laxity at the maximum manual force with a KT- 1000 Knee Arthrometer was 0.2 ± 0.9 mm, with 95.1% of patients ranging from - 1 to + 2 mm. CONCLUSION: By identifying arthroscopic landmarks, the entire femoral tunnel aperture and at least 75% of the entire tibial tunnel aperture area were consistently located inside the anatomical attachment areas. With properly created tunnels inside the anatomical attachment areas, the ART ACLR using a BTB graft could provide satisfactory outcomes both subjectively and objectively in more than 95% of patients. LEVEL OF EVIDENCE: Case series, Level IV.

Second-look arthroscopy after anatomic anterior cruciate ligament reconstruction: Bone-patellar tendon-bone versus hamstring tendon graft.

PURPOSE: The purpose of this study was to compare the morphological and clinical outcomes between anatomic rectangular tunnel (ART) ACL reconstruction with a BTB graft and anatomic triple-bundle (ATB) ACL reconstruction with hamstring tendon (HST) grafts. METHODS: The anatomic ACL reconstructions were performed on 467 patients; 233 patients with ART technique and 234 with ATB procedure. ART procedure was predominantly indicated for athletes with higher motivation to return to sports and aggressiveness for muscle training. A total of 113 patients, with a mean age of 20.7 years, had consented to undergo second-look arthroscopy. The average time from ACL reconstruction to the second-look was 10.0 months. This study included 56 ART techniques and 57 ATB procedures. The grafts underwent meticulous probing, and were evaluated based on tension, graft damage, and synovial coverage. Moreover, the femoral tunnel aperture was also observed in detail to assess the space between the femoral tunnel and the graft. As clinical evaluation, knee effusion, range of motion, Lachman test, pivot shift test, KT side-to-side difference, and Lysholm score were assessed. RESULTS: There was no significant difference in graft tension between two procedures, while HST graft in ATB procedure had more cases with graft damage (p = 0.05). Good synovial coverage was found in 98% in ART procedure and 70% in ATB procedure, showing a significant difference (P < 0.001). At femoral tunnel aperture, there were no cases with the space around BTB graft, while 33% showed the space around HST graft, again showing a significant difference (P < 0.001). There were no significant differences in clinical outcomes. CONCLUSION: BTB graft with the ART procedure was superior to HST graft with the ATB procedure in morphology at second-look arthroscopy, while there was no significant difference in clinical outcomes between two procedures.

Early Structural Results After Anatomic Triple Bundle Anterior Cruciate Ligament Reconstruction Validated by Tunnel Location, Graft Orientation, and Static Anteroposterior Tibia-Femur Relationship.

PURPOSE: To elucidate how closely the structural characteristics of the anterior cruciate ligament (ACL) grafts after anatomic triple bundle (ATB) reconstruction resembled those of the normal ACL. METHODS: From 2012 to 2016, patients who underwent primary ATB ACL reconstruction using hamstring tendon autografts and the same number of healthy control subjects were included. Using magnetic resonance imaging (MRI) taken at 6 months postoperatively, ACL graft orientation was evaluated by the angles against the tibial plateau measured in the sagittal and oblique coronal planes at the anteromedial and posterolateral portions (ACL-tibial plateau angle [ATA]). For factors affecting the graft orientation, the static tibiofemoral relationship was evaluated by anteroposterior tibial translocation (APTT) in the identical MRI using a previously established method, and tunnel locations were evaluated using the quadrant method. To test equivalence, the widely used two one-sided test procedure was performed, with the equivalence margins of 5° and 3 mm for ATA and APTT, respectively. RESULTS: Thirty-five patients were enrolled for each group. ATAs were not significantly different, and the 95% confidence interval (CI) of these differences was within 5° (sagittal: P = .211 [95% CI, -2.9 to 0.6]; oblique coronal ATA for the anteromedial and posterolateral portions: P = .269 [95% CI, -1.9 to 0.5] and P = .456 [95% CI,-2.1 to 0.9], respectively). The difference in APTT was neither statistically nor clinically significant (P = .114; 95% CI, -2.0 to 0.2). CONCLUSIONS: These data suggest that ACL grafts using the ATB technique achieved a graft orientation equivalent to that of the normal ACL, with an equivalent postoperative anteroposterior tibiofemoral relationship in the static MRI. Thus, the ATB ACL reconstruction technique with the presented tunnel locations produced grafts that were similar to the native ACL in orientation. LEVEL OF EVIDENCE: Level III, case-control study.

Vibration acceleration enhances proliferation, migration, and maturation of C2C12 cells and promotes regeneration of muscle injury in male rats.

Vibration acceleration (VA) using a whole-body vibration device is beneficial for skeletal muscles. However, its effect at the cellular level remains unclear. We aimed to investigate the effects of VA on muscles in vitro and in vivo using the C2C12 mouse myoblast cell line and cardiotoxin-induced injury in male rat soleus muscles. Cell proliferation was evaluated using the WST/CCK-8 assay and proportion of Ki-67 positive cells. Cell migration was assessed using wound-healing assay. Cell differentiation was examined by the maturation index in immunostained cultured myotubes and real-time polymerase chain reaction. Regeneration of soleus muscle in rats was assessed by recruitment of satellite cells, cross-sectional area of regenerated muscle fibers, number of centrally nucleated fibers, and conversion of regenerated muscle from fast- to slow-twitch. VA at 30 Hz with low amplitude for 10 min promoted C2C12 cell proliferation, migration, and myotube maturation, without promoting expression of genes related to differentiation. VA significantly increased Pax7-stained satellite cells and centrally nucleated fibers in injured soleus muscles on Day 7 and promoted conversion of fast- to slow-twitch muscle fibers with an increase in the mean cross-sectional area of regenerated muscle fibers on Day 14. VA enhanced the proliferation, migration, and maturation of C2C12 myoblasts and regeneration of injured rat muscles.

Goal Orientation and Desire for Approval Were Associated With Sports Injuries Among Young Japanese Athletes.

Introduction: This study aimed to clarify the relationship between psychological factors (goal orientation and desire for approval from others) and the severity of sports injuries experienced by young Japanese athletes. Methods: A total of 560 young Japanese athletes (328 males and 232 females) aged 18-24 years completed an online survey in 2022-2023. A web questionnaire was used to investigate participants' task and ego orientations, desire for approval from others (e.g., coaches and friends/families), and history of injury. The samples were then split into 3 groups on the basis of the rest duration due to the injury: noninjury group (0 days), mild-to-moderate injury group (1-27 days), and severe injury group (>28 days). Spearman's test examined a correlation between task and ego orientation scores among all samples. The Mann-Whitney U test was used to compare the scores between the severe injury and noninjury groups. Result: A significant positive correlation was found between task and ego orientation scores from all samples (ρ=0.27, p<0.001). The severe injury group had significantly higher task orientation scores and desire for approval scores than the noninjury group (ρ=0.001, p<0.001). Conclusions: Japanese young athletes with high task orientation and approval desire may be at risk of severe sports injuries requiring >4 weeks to return to sports. The goal orientation profiles should be interpreted with caution. Future research should examine contextual effects such as the perceived motivational climate, in addition to the goal orientation profiles.

The prevalence of shoulders with a large glenoid defect and small bone fragment increases after several instability events during conservative treatment for traumatic anterior instability.

Background: Unstable shoulders with a large glenoid defect and small bone fragment are at higher risk for postoperative recurrence after arthroscopic Bankart repair. The purpose of the present study was to clarify the changes in the prevalence of such shoulders during conservative treatment for traumatic anterior instability. Methods: We retrospectively investigated 114 shoulders that underwent conservative treatment and computed tomography (CT) examination at least twice after an instability event in the period from July 2004 to December 2021. We investigated the changes in glenoid rim morphology, glenoid defect size, and bone fragment size from the first to the final CT. Results: At first CT, 51 shoulders showed no glenoid bone defect, 12 showed glenoid erosion, and 51 showed a glenoid bone fragment [33 small bone fragment (<7.5%) and 18 large bone fragment (≥7.5%); mean size: 4.9 ± 4.2% (0-17.9%)]. Among patients with glenoid defect (fragment and erosion), the mean glenoid defect was 5.4 ± 6.6% (0-26.6%); 49 were considered a small glenoid defect (<13.5%) and 14 were a large glenoid defect (≥13.5%). While all 14 shoulders with large glenoid defect had a bone fragment, small fragment was solely seen in 4 shoulders. At final CT, 23 of the 51 shoulders persisted without glenoid defect. The number of shoulders presenting glenoid erosion increased from 12 to 24, and the number of shoulders with bone fragment increased from 51 to 67 [36 small bone fragment and 31 large bone fragment; mean size: 5.1 ± 4.9% (0-21.1%)]. The prevalence of shoulders with no or a small bone fragment did not increase from first CT (71.4%) to final CT (65.9%; P = .488), and the bone fragment size did not decrease (P = .753). The number of shoulders with glenoid defect increased from 63 to 91 and the mean glenoid defect significantly increased to 9.9 ± 6.6% (0-28.4%) (P < .001). The number of shoulders with large glenoid defect increased from 14 to 42 (P < .001). Of these 42 shoulders, 19 had no or a small bone fragment. Accordingly, among a total of 114 shoulders, the increase from first to final CT in the prevalence of a large glenoid defect accompanied by no or a small bone fragment was significant [4 shoulders (3.5%) vs. 19 shoulders (16.7%); P = .002]. Conclusions: The prevalence of shoulders with a large glenoid defect and small bone fragment increases significantly after several instability events.

Vibration acceleration promotes endochondral formation during fracture healing through cellular chondrogenic differentiation.

Vibration acceleration through whole body vibration has been reported to promote fracture healing. However, the mechanism responsible for this effect remains unclear. Purpose of this study was to determine whether vibration acceleration directly affects cells around the fracture site and promotes endochondral ossification. Four-week-old female Wistar Hannover rats were divided into two groups (vibration [V group] and control [C group]). The eighth ribs on both sides were cut vertically using scissors. From postoperative day 3 to 11, vibration acceleration using Power Plate® (30 Hz, low amplitude [30-Low], 10 min/day) was applied in the V group. Mature calluses appeared earlier in the V group than in the C group by histological analysis. The GAG content in the fracture callus on day 6 was significantly higher in the V group than in the C group. The mRNA expressions of SOX-9, aggrecan, and Col-II in the fracture callus on day 6 and Col-X on day 9 were significantly higher in the V group than in the C group. For in vitro analysis, four different conditions of vibration acceleration (30 or 50 Hz with low or high amplitude [30-Low, 30-High, 50-Low, and 50-High], 10 min/day) were applied to a prechondrogenic cell (ATDC5) and an undifferentiated cell (C3H10T1/2). There was no significant difference in cell proliferation between the control and any of the four vibration conditions for both cell lines. For both cell lines, alcian blue staining was greater under 30-Low and 50-Low conditions than under control as well as 30-High and 50-High conditions on days 7 and 14. Vibration acceleration under 30-L condition upregulated chondrogenic gene expressions of SOX-9, aggrecan, Col-II, and Col-X. Low-amplitude vibration acceleration can promote endochondral ossification in the fracture healing in vivo and chondrogenic differentiation in vitro.

Enlargement of drill holes after use of a biodegradable suture anchor: quantitative study on consecutive postoperative radiographs.

PURPOSE: Osteolysis around a biodegradable device has been warned of in several reports. We investigated variations of drill holes of polylactic acid (PLA) suture anchors in consecutive radiographs after arthroscopic capsulolabral repair to assess the influence of enlargement of the drill holes on clinical outcome. METHODS: Twenty patients who underwent arthroscopic capsulolabral repair using 3 Panalok suture anchors for traumatic anterior shoulder instability were included in the study. The mean follow-up period was 25.8 months. From radiographs taken on postoperative day 1, at 3 and 12 months, and at the latest follow-up, the diameter of each drill hole was measured. The diameter enlargement ratio was calculated for each drill hole by dividing each diameter by the corresponding day-1 diameter. The patients were divided into 2 groups based on the degree of enlargement of drill holes (greater or less than the mean + 1 standard deviation [SD]) and the clinical outcome of each group was evaluated according to the Rowe score and range of motion. RESULTS: Diameter enlargement ratios tended to increase with time (P = .0152 for 3 v 12 months postoperatively, and P = .0049 for 3 v latest follow-up). Three drill holes out of 53, 17 out of 60, and 11 out of 47 showed enlargement over the mean + 1 SD, at 3 and 12 months postoperatively and at latest follow-up, respectively. Eleven patients had such enlarged drill holes, and had significantly poor Rowe score (70.9 v 95.6 points; P = .0267) at latest follow-up. CONCLUSIONS: A drill hole filled with a PLA anchor tended to enlarge over time. We found that 55% of patients had at least 1 drill hole that enlarged beyond the mean + 1 SD. These patients had significantly less favorable results in function and stability. The present study raises concern about the use of PLA suture anchors for the fixation of detached glenoid labrum. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Superior Bennett lesion: a bone fragment at the posterosuperior glenoid rim in 5 athletes.

In throwing athletes, a Bennett lesion is a bony spur that usually forms at the posteroinferior glenoid rim and sometimes becomes painful. We encountered superior Bennett lesions in the shoulders of 5 athletes, which were detected at the posterosuperior glenoid rim as a separate bone fragment. In all 5 athletes this lesion appeared to be the main cause of shoulder pain during throwing or overhead activity. The lesions were easily visualized on plain radiographs (axial view, scapular Y view, and 45 degrees craniocaudal view) or computed tomography scans. Tenderness was detected over the posterior aspect of the glenohumeral joint, the pain provocation test specific for SLAP lesions was positive, and posterior shoulder pain was elicited by forced external rotation at 90 degrees of abduction in all 5 cases. The pain was diminished or decreased by injection of local anesthetic around the lesion. At arthroscopy, detachment of the posterosuperior labrum and posterior capsular tightness were detected in all 5 cases. Through the detached portion of the posterosuperior labrum, we could easily reach an unstable mobile bone fragment, which was resected arthroscopically. Although the pathologic mechanism is unclear, the mobility of the bone fragment appeared to be related to the occurrence of symptoms.

Clinical Outcome of Arthroscopic Bankart Repair Combined With Simultaneous Capsular Repair.

BACKGROUND: A capsular tear and humeral avulsion of the glenohumeral ligament lesion are not uncommon findings in association with a Bankart lesion. However, there have been few reports regarding the prevalence of such capsular lesions and the postoperative recurrence after capsular repair. Purpose/Hypothesis: This study investigated the prevalence of capsular lesions and clarified their influence on the postoperative recurrence of instability. In addition, factors were identified that were associated with the occurrence of capsular lesions and the postoperative recurrence of instability. We hypothesized that clinical outcomes would be improved by combining arthroscopic Bankart repair with simultaneous capsular repair. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Capsular lesions were retrospectively examined through operative records, still pictures, and videos in 172 shoulders with traumatic anterior instability. First, the prevalence of capsular lesions and their severity were investigated. Then, postoperative recurrence was determined in shoulders observed for a minimum of 2 years. Finally, factors were assessed that were associated with the occurrence of capsular lesions and the postoperative recurrence of instability. RESULTS: A capsular lesion was recognized in 37 shoulders (21.5%), being severe and mild in 20 and 17, respectively. All were repaired simultaneously with the arthroscopic Bankart procedure. After follow-up for at least 2 years, recurrence of instability was detected in 10 of 34 shoulders (29.4%), including 6 (31.6%) with severe capsular lesions and 4 (26.7%) with mild lesions. The recurrence rate was significantly higher in shoulders with a capsular lesion than in shoulders without a capsular lesion (18 of 120, 15%; P = .013), but there was no significant difference between severe and mild lesions. Regardless of the sport played, capsular lesions were significantly more frequent in patients ≥30 years old, patients with complete dislocation, and patients with a coexisting Hill-Sachs lesion. Postoperative recurrence of instability was significantly more frequent in patients <30 years and competitive athletes. CONCLUSION: In shoulders undergoing arthroscopic Bankart repair, capsular lesions were often present and were associated with higher postoperative recurrence of instability. While these lesions were more frequent in older patients, postoperative recurrence of instability was more likely in young competitive athletes.

Novel flat and wide meniscal repair material improves the ultimate load of knot breakage in a porcine trans-capsular meniscal repair model.

BACKGROUND: In the meniscal repair procedures, a high ultimate load capacity and low cyclic creep at the repair site are favorable and lead to good biological incorporation of the tear site after surgery. Previous biomechanical tensile tests of the meniscal sutures have identified the suture knot as the weakest point. We hypothesized that the strength of a suture knot depends on the suture shape, and therefore, we compared three differently shaped suture materials composed of the same material and quantity per length. The purpose of this study was to determine whether a novel flat and wide repair material (FWRM), which consists of braided multi-threads that are cross-sectionally flat and wide, improves the ultimate load of knot breakage in a biomechanical experiment using a porcine trans-capsular meniscal repair model. METHODS: Eighteen fresh-frozen porcine knees (n = 6 in each group) were used. A longitudinal tear in the middle segment of the medial meniscus was created and repaired with a trans-capsular inside-out method using the following suture materials: No. 2-0 braided polyester conventional suture, hollow suture, and FWRM. After the separation of the inner segment of the meniscus with leaving, the suture stability of the repaired menisci was biomechanically analyzed with a video camera system for widening after a cyclic load between 5 and 20 N was applied 300 times. Ultimate failure load and stiffness at 5 mm/ min were also analyzed. RESULTS: We found no significant difference in suture widening after cyclic load tests [conventional suture, mean 0.51 mm (S.D. 0.39 mm); hollow suture, mean 0.23 mm (S.D. 0.11 mm); and FWRM, mean 0.54 mm (S.D. 0.08 mm)]. The failure mode in all specimens was knot breakage. Compared with those of the other groups, the ultimate failure load of FWRM was statistically significantly higher in the load-to-failure tests (conventional suture, mean 58.8 N [S.D. 8.25 N]; hollow suture, mean 79.4 N [S.D. 10.2 N]; and FWRM, mean 97.4 N [S.D. 3.65 N]; p < 0.05). CONCLUSION: FWRM improves the ultimate load of knot breakage without altering stability. This material may contribute to safe and stable meniscus repair.

Throwing shoulder injury involving the anterior rotator cuff: concealed tears not as uncommon as previously thought.

PURPOSE: In throwing athletes, partial rotator cuff tears are usually located posterior to the site of the common rotator cuff tears seen in the general nonthrowing population. However, they sometimes have tears located around the anterior aspect of the supraspinatus tendon. In this study we investigated the characteristics of anterior rotator cuff tears in throwing athletes. We then compared several factors between anterior tears and posterior tears to investigate those related to the presence of anterior tears or the occurrence of such tears. METHODS: We divided 37 athletes with partial rotator cuff tears into those with anterior tears (n = 17) and those with posterior tears (n = 20). The clinical profile, range of motion and joint laxity with patient under general anesthesia, and operative findings were retrospectively compared between the 2 groups. RESULTS: Among the 17 anterior rotator cuff tears, 12 tears were confined to the anterior one third of the supraspinatus tendon. Interestingly, concealed intratendinous degenerative tears were found in 6 shoulders. These appeared to be very shallow articular-side tears located around the attachment of the greater tuberosity, but severe tears were exposed after resection of the residual capsular portion of the tendon. Posterior capsular tightness was significantly related to the occurrence of anterior tears, whereas a greater tuberosity notch was significantly related to posterior tears. CONCLUSIONS: Anterior rotator cuff tears are not uncommon in throwing athletes, and a concealed type of tear was a representative lesion. Different mechanisms may be involved in the development of anterior and posterior rotator cuff tears resulting from throwing injuries. Posterior capsular tightness might influence the occurrence of anterior tears. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Bone fragment union and remodeling after arthroscopic bony bankart repair for traumatic anterior shoulder instability with a glenoid defect: influence on postoperative recurrence of instability.

BACKGROUND: Although good clinical outcomes have been reported after arthroscopic bony Bankart repair, the extent of bone union is still unclear. PURPOSE: To investigate bone union after arthroscopic bony Bankart repair and its influence on postoperative recurrence of instability. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Among 113 consecutive shoulders that underwent arthroscopic bony Bankart repair, postoperative evaluation of bone union by computed tomography (CT) was performed at various times in 81 shoulders. Bone union was investigated during 3 periods: 3 to 6 months postoperatively (first period), 7 to 12 months postoperatively (second period), and 13 months or more postoperatively (third period). The influence of the size of the preoperative glenoid defect and the size of the bone fragment on bone union was investigated, as well as the influence of bone union on postoperative recurrence of instability. In shoulders with bone union, bone fragment remodeling and changes in the glenoid defect size were also investigated. RESULTS: The bone union rate was 30.5% in the first period, 55.3% in the second period, and 84.6% in the third period. Among 53 shoulders with CT evaluation in the second period or later and follow-up for a minimum of 1 year, there was complete union in 33 shoulders (62.3%), partial union in 3 (5.7%), nonunion in 8 (15.1%), and no fragment on CT in 9 (17.0%). The complete union rate was 50% for 22 shoulders with small bone fragments (<5% of the glenoid diameter), 56.3% for 16 shoulders with medium fragments (5%-10%), and 86.7% for 15 shoulders with large fragments (>10%). The recurrence rate for postoperative instability was only 6.1% for shoulders with complete union, while it was 50% for shoulders with partial union, nonunion, no fragment, and no fragment on CT. The recurrence rate was significantly higher (36.4%) in shoulders with small fragments, but it was significantly lower in shoulders with bone union. In shoulders with bone union, the bone fragment frequently became larger over time, while the size of the glenoid defect decreased significantly from 18.6% preoperatively to 4.7% postoperatively. CONCLUSION: Bone union was not always achieved after arthroscopic bony Bankart repair, and union was often delayed. Recurrence of instability was significantly more frequent when bone union failed. The size of the glenoid defect decreased significantly in shoulders with bone union.

One-stage revision anatomic anterior cruciate ligament reconstruction with rectangular tunnel technique.

We developed the anatomic rectangular tunnel anterior cruciate ligament reconstruction (ART ACLR) with a bone-patellar tendon-bone graft to mimic fibre arrangement inside the native ACL via tunnels with smaller apertures. With a 10-mm-wide graft, the cross-sectional area of the tunnels of 50 mm2 in ART ACLR is less than that of 79 mm2 in a 10-mm round tunnel one. Because tunnel encroachment would be less of a problem, the ART ACLR technique could be most frequently applied to patients after a failed primary ACLR. In this instructional lecture, the indication and technical considerations for ART ACLR as one-stage revision ACLR are described.

Relationship Between Glenoid Defects and Hill-Sachs Lesions in Shoulders With Traumatic Anterior Instability.

BACKGROUND: While the combination of a glenoid defect and a Hill-Sachs lesion in a shoulder with anterior instability has recently been termed a bipolar lesion, their relationship is unclear. PURPOSE: To investigate the relationship of the glenoid defect and Hill-Sachs lesion and the factors that influence the occurrence of these lesions as well as the recurrence of instability. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: The prevalence and size of both lesions were evaluated retrospectively by computed tomography scanning in 153 shoulders before arthroscopic Bankart repair. First, the relationship of lesion prevalence and size was investigated. Then, factors influencing the occurrence of bipolar lesions were assessed. Finally, the influence of these lesions on recurrence of instability was investigated in 103 shoulders followed for a minimum of 2 years. RESULTS: Bipolar lesions, isolated glenoid defects/isolated Hill-Sachs lesions, and no lesion were detected in 86, 45, and 22 shoulders (56.2%, 29.4%, and 14.4%), respectively. As the glenoid defect became larger, the Hill-Sachs lesion also increased in size. However, the size of these lesions showed a weak correlation, and large Hill-Sachs lesions did not always coexist with large glenoid defects. The prevalence of bipolar lesions was 33.3% in shoulders with primary instability and 61.8% in shoulders with recurrent instability. In relation to the total events of dislocations/subluxations, the prevalence was 44.2% in shoulders with 1 to 5 events, 69.0% in shoulders with 6 to 10 events, and 82.8% in shoulders with ≥11 events. Regarding the type of sport, the prevalence was 58.9% in athletes playing collision sports, 53.3% in athletes playing contact sports, and 29.4% in athletes playing overhead sports. Postoperative recurrence of instability was 0% in shoulders without lesions, 0% with isolated Hill-Sachs lesions, 8.3% with isolated glenoid defects, and 29.4% with bipolar lesions. The presence of a bipolar lesion significantly influenced the recurrence rate, but lesion size did not. CONCLUSION: The prevalence of bipolar lesions was approximately 60%. As glenoid defects became larger, Hill-Sachs lesions also enlarged, but there was no strong correlation. Bipolar lesions were frequent in patients with recurrent instability, patients with repetitive dislocation/subluxation, and those playing collision/contact sports. Instability showed a high recurrence rate in shoulders with bipolar lesions.

Excursion of bone-patella tendon-bone grafts during the flexion-extension movement in anterior cruciate ligament reconstruction: Comparison between isometric and anatomic reconstruction techniques.

BACKGROUND/OBJECTIVE: The purpose of this study was to elucidate the biomechanical differences between anterior cruciate ligament (ACL) grafts reconstructed by isometric and anatomic reconstruction techniques, based on their length changes. METHODS: One hundred and thirty-three knees with primary ACL reconstruction using the bone-patellar tendon-bone (BTB) graft were retrospectively identified. Twenty-two knees and 111 knees underwent isometric round tunnel (IRT) ACL reconstruction and anatomic rectangular tunnel (ART) ACL reconstruction, respectively. RESULTS: After femoral-side fixation of the graft in the surgery, the length change of the graft from 120° flexion to full extension was measured by using an isometric positioner at the tibial side. Both reconstructive techniques showed little length change from 120° to ∼20° of flexion, followed by elongation of the graft, until full extension. The amount of length change of the grafts was 1.0 ± 0.7 mm with the IRT technique, and 3.4 ± 0.9 mm with the ART technique. These findings were significantly different, based on the Mann-Whitney U test (p < 0.001). CONCLUSION: The native ACL has an intrinsic length change of 3-6 mm, and therefore the ART technique may more closely replicate the biomechanical function of the native ACL.

Enlargement of Glenoid Defects in Traumatic Anterior Shoulder Instability: Influence of the Number of Recurrences and Type of Sport.

BACKGROUND: Large glenoid rim defects in patients with traumatic anterior shoulder instability are often regarded as a contraindication for arthroscopic Bankart repair, with a defect of 20% to 27% considered as the critical size. While recurrence of dislocations, male sex, and collision sports were reported to be the significant factors influencing large glenoid defects, the influences of subluxations and more detailed types of sports were not investigated. PURPOSE: To investigate the influence of the number of dislocations and subluxations and type of sport on the occurrence and size of glenoid defects in detail. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 223 shoulders (60 with primary instability, 163 with recurrent instability) were prospectively examined by computed tomography. Glenoid rim morphology was compared between primary and recurrent instability. In patients with recurrent instability, the relationship between the glenoid defect and the number of dislocations and subluxations was investigated. In addition, glenoid defects were compared among 49 male American football players, 41 male rugby players, 27 male baseball players, and 25 female athletes. RESULTS: The mean extent of the glenoid defect was 3.5% in shoulders with primary instability and 11.3% in those with recurrent instability. A glenoid defect was detected in 108 shoulders (66.2%) with recurrent instability versus 12 shoulders (20%) with primary instability. Regarding the influence of the total number of dislocations/subluxations, the average extent of the glenoid defect was 6.3% in 85 shoulders with 2 to 5 events, 12.9% in 34 shoulders with 6 to 10 events, and 19.6% in 44 shoulders with 11 or more events. The glenoid defect became significantly larger along with an increasing number of recurrences. Although recurrent subluxation without dislocation also influenced the glenoid defect size, the number of dislocations did not. The average extent of the glenoid defect was 12.0% in rugby players, 8.9% in American football players, 4.7% in female athletes, and 4.5% in baseball players. Glenoid defects were significantly smaller in male baseball players and female athletes than in male collision athletes. CONCLUSION: The glenoid defect is significantly enlarged by damage due to recurrent dislocation and subluxation; therefore, glenoid rim morphology differs markedly between primary and recurrent instability. Glenoid defect size is also influenced by sex and by the type of sport.

Specifically modified osteopontin in rheumatoid arthritis fibroblast-like synoviocytes supports interaction with B cells and enhances production of interleukin-6.

OBJECTIVE: Osteopontin (OPN) is expressed by fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA), but its pathologic role is still obscure. The present study was undertaken to analyze the role of OPN in RA by focusing on its effects on cell-cell interactions between FLS and B lymphocytes. METHODS: FLS obtained from 10 patients with RA and 10 non-RA subjects and a B lymphocyte cell line were studied. The characteristics of OPN expression by FLS were analyzed by Western blotting, immunoprecipitation, and immunofluorescence studies. In cocultures of FLS and B lymphocytes, the effects of OPN on adhesion of B lymphocytes to FLS and the consequent production of interleukin-6 (IL-6) were analyzed in experiments involving overexpression and knockdown of OPN and inhibitory studies with an OPN-blocking antibody. In vivo, the expression of OPN in RA synovium was examined by immunohistochemistry. RESULTS: A specifically modified 75-kd form of OPN was predominantly expressed in RA FLS, and this was associated with expression of >200-kd thrombin-cleaved OPN that was crosslinked with fibronectin and localized on the surface of the FLS. In FLS-B lymphocyte cocultures, 75-kd OPN-positive FLS produced a significantly higher amount of IL-6 than did 75-kd OPN-negative FLS. When the FLS were separated from B lymphocytes or cultured alone, the production of IL-6 was low and was not significantly different between these 2 culture conditions. Moreover, OPN overexpression enhanced production of IL-6 in 75-kd OPN-positive FLS-B lymphocyte cocultures. Addition of the OPN-blocking antibody inhibited the adhesion of B lymphocytes to FLS. Immunohistochemical analyses revealed that localization of IL-6-positive cells coincided with the sites at which OPN and B lymphocytes were colocalized. CONCLUSION: Specifically modified 75-kd OPN was expressed by RA FLS. This form of OPN affected FLS-B lymphocyte interactions by supporting the adhesion of B lymphocytes to FLS and enhancing the production of IL-6.