Mechanical Evaluation of Bone-Patellar Tendon-Bone Graft Fixation to the Tibia in ACL Reconstruction: Bone Plug Tensioning and Fixation System versus Interference Screw.

This study aimed to evaluate the mechanical properties of bone plug fixation to the tibia with a novel device, the Bone plug Tensioning and Fixation (BTF) system.Forty bone-tendon-bone grafts consisting of the whole patella-patellar tendon-tibial bone plug of 10-mm width and tibiae from the porcine were prepared. After creating a 10-mm tibial tunnel, the tibial bone plug was fixed to the tibia with the BTF system or the interference screw (IFS) to prepare a test specimen of the patella-patellar tendon-tibial bone plug fixed to the tibia. For the graft tension controllability study, a predetermined initial tension of 9.8 or 19.6 N was applied and maintained for 5 minutes. Then the bone plug was fixed to the tibia with the BTF system or IFS in 10 specimens, monitoring the residual tension for an additional 5 minutes. Then, a cyclic loading test and a tension-to-failure test were performed.The mean difference between the residual tension and the predetermined tension was significantly smaller in BTF fixation (9.8 N → 10.6 ± 2.2 N; 19.6 N → 18.9 ± 2.1 N) than in IFS fixation (9.8 N → 23.4 ± 7.4 N; 19.6 N → 28.9 ± 11.5 N). The mean displacement of the bone plug after cyclic loading was significantly less in the BTF group (1.2 ± 0.6 mm) than in the IFS group (2.2 ± 1.0 mm; p < 0.01). Stiffness was significantly greater in the BTF group (504.6 ± 148.8 N/mm) than in the IFS group (294.7 ± 96.7 N/mm; p < 0.01), whereas the maximum failure loads in the two groups did not differ significantly (724.2 ± 180.3 N in the BTF and 634.8 ± 159.4 N in the IFS groups).BTF system better performed in graft tension controllability than IFS did. BTF fixation was superior to IFS fixation in the displacement of the bone plug during the cyclic loading test and in stiffness in the tension-to-failure test.

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.

New bone formation after arthroscopic Bankart repair for unstable shoulders with an erosion-type glenoid defect.

BACKGROUND: The purpose of the present study was to retrospectively evaluate new bone formation after arthroscopic Bankart repair (ABR) and the influence of new bone formation on recurrence in shoulders with an erosion-type glenoid defect. METHODS: We analyzed data on shoulders with an erosion-type glenoid defect. Participants were patients who underwent computed tomography to evaluate new bone formation after ABR performed from 2004 to 2021 and were followed for a minimum of 2 years. We investigated the factors influencing new bone formation, in particular the presence of an intraoperative bone fragment, and the influence of new bone formation and its size on postoperative recurrence. RESULTS: A total of 100 shoulders were included. The mean glenoid defect size was 10.1% ± 6.3% (range, 1.2%-31.5%). New bone formed postoperatively in 15 shoulders (15.0%) and was seen in significantly more shoulders with an intraoperative bone fragment (11 of 18, 61.1%) than in those without a fragment (4 of 82, 4.9%; P < .001). Recurrence occurred in 22 shoulders (22.0%), and the rate of recurrence was not different between shoulders with new bone formation (3 of 15, 20.0%) and without new bone formation (19 of 85, 22.4%; P = .999). Among the 15 shoulders with new bone formation, the size of the new bone fragments relative to glenoid width was <5% in 2 shoulders, 5%-<7.5% in 8 shoulders, 7.5%-<10% in 3 shoulders, and ≥10% in 2 shoulders; in all 3 shoulders with postoperative recurrence, the relative size was <7.5%. CONCLUSIONS: Even in shoulders with an erosion-type glenoid defect, new bone may form after ABR, especially in shoulders with an intraoperative bone fragment. However, new bone formation does not decrease the rate of postoperative recurrence.

Anatomical Triple Bundle Anterior Cruciate Ligament Reconstructions With Hamstring Tendon Autografts: Tunnel Locations and 2-Year Clinical Outcomes.

PURPOSE: To anatomically clarify the location of the tunnel apertures created using the bony landmark strategy and to elucidate clinical outcomes after anatomic triple-bundle (ATB) anterior cruciate ligament (ACL) reconstruction. METHODS: Thirty-two patients with unilateral ACL injury who had consented to undergo computed tomography (CT) at 3 weeks, as well as 2-year follow-up evaluation, were enrolled. At the time of surgery, remnant tissues were thoroughly cleared to create 2 femoral and 3 tibial tunnels inside the ACL attachment areas bordered by the bony landmarks. Two double-looped semitendinosus tendon autografts were prepared and fixed on the femur with two EndoButton-CLs and secured to the tibia with pullout sutures and plates with 10-20N of tension. The location of the tunnel aperture areas was assessed using 3-dimensional CT images, and 2-year postoperative clinical outcomes were evaluated. RESULTS: The CT evaluation showed 100% of the femoral tunnel aperture area and at least 79% of the tibial tunnel aperture area were located inside the anatomic attachment areas. Thirty patients were available for clinical evaluation. The International Knee Documentation Committee subjective assessment showed all of the patients were classified as "normal" or "nearly normal." Lachman and pivot-shift tests were negative in 100% and 93%, respectively. The mean side-to-side difference of anterior laxity at the maximum manual force with a KT-1000 Knee Arthrometer was 0.7 ± 0.7 mm, ranging from 0 to 2 mm. CONCLUSION: In ATB ACL reconstructions with hamstring tendon grafts, the tunnels can be created in proper locations using the arthroscopically-identifiable bony landmarks. Moreover, ATB ACL reconstruction with hamstring tendon grafts via the proper tunnels result in consistently satisfactory clinical outcomes. LEVEL OF EVIDENCE: Level IV, case series.

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.

Progression of Erosive Changes of Glenoid Rim After Arthroscopic Bankart Repair.

PURPOSE: To evaluate changes of the glenoid after arthroscopic Bankart repair (ABR) in patients with different preoperative glenoid structures. METHODS: Patients who underwent ABR for traumatic anterior shoulder instability were retrospectively investigated. They were divided into 3 groups on the basis of preoperative glenoid structure by computed tomography (CT): normal glenoid (group N), glenoid erosion (group E), or glenoid defect associated with a bony Bankart lesion (group B). Shoulders in group B were also stratified according to the postoperative status of the bone fragment (union, nonunion, or resorbed). Postoperative changes of glenoid width (Δ) (increase: Δ ≥5%, stable: Δ >-5% to <5%, decrease: Δ ≤-5%) and the extent of glenoid bone loss were investigated by 3-dimensional CT. RESULTS: A total of 186 shoulders were divided into 3 groups: group N (n = 61), group E (n = 46), and group B (n = 79). At initial postoperative CT, the glenoid width was decreased in 41 shoulders, stable in 20 shoulders, and increased in no shoulders from group N. The respective numbers were 27, 18, and 1 in group E, and 50, 22, and 7 in group B. The glenoid width was reduced in all groups (mean percent change: -8.8%, -5.9%, and -6.1%, respectively). In group B, glenoid width decreased in most of the shoulders without bone union. The glenoid bone loss on the preoperative and postoperative final CT was, respectively, 0% and 8.6% in group N (P < .0001), 9.9% and 12.4% in group E (P = .03), and 10.4% and 7.2% in group B (P = .01). Final glenoid bone loss >13.5% was recognized in 18.2% of group N, 35.7% of group E, and 21.8% of group B. CONCLUSIONS: Glenoid width often decreased after ABR because of anterior glenoid rim erosion, and this change was frequent in patients with preoperative normal glenoid, glenoid erosion, or without postoperative union of a bony Bankart lesion. LEVEL OF EVIDENCE: Level 3, Case-control study.

Biomechanical comparison of meniscus-suture constructs for pullout repair of medial meniscus posterior root tears.

BACKGROUND: Transtibial pullout repair for posterior meniscus root tear is widely performed to restore meniscal function. However, it is sometimes technically difficult to pass the suture through the posterior medial meniscus root in narrow joint space. To address this limitation, a new suture technique using an all-inside meniscal suture device through the tibial tunnel was proposed. The purpose of the present study was to compare the biomechanical properties of a meniscus-suture construct prepared using an all-inside meniscal suture device and those of the construct prepared using conventional suture techniques. METHODS: A total of 18 fresh-frozen porcine medial menisci were used and randomly divided into three groups according to the type of suturing technique applied. Three suturing methods were evaluated: suturing with all-inside meniscal suture device, single simple suture, and double simple sutures. All specimens were subjected to cyclic loading of 300 cycles followed by a load-to-failure test. The displacement after cyclic loading, the ultimate failure load, and the mode of failure were evaluated. RESULTS: There was no significant difference among the three suturing techniques regarding both displacement after cyclic loading and ultimate failure load. Suture breakage was the most common failure mode in each group. CONCLUSIONS: The biomechanical properties of meniscus-suture construct with the all-inside meniscal suture device were equivalent to those obtained using conventional suture techniques. Our results suggest that pullout repair using the all-inside meniscal suture device through the tibial tunnel could serve as an alternative suture technique for the repair of posterior meniscus root tears.

The Development Process of Bipolar Bone Defects From Primary to Recurrent Instability in Shoulders With Traumatic Anterior Instability.

BACKGROUND: Recurrence of glenohumeral joint instability after primary traumatic anterior instability is not rare, and bipolar bone loss is one of the most critical factors for recurrent instability, but the development process of bipolar bone defects is still unclear. PURPOSE: To investigate the development process of bipolar bone defects from primary to recurrent instability among shoulders with traumatic anterior instability evaluated at least twice by computed tomography (CT). STUDY DESIGN: Case series; Level of evidence, 4. METHODS: There were 44 patients (47 shoulders) with recurrence after primary instability in which bone morphology was evaluated by 3-dimensional reconstructed CT at primary instability (initial CT) and after recurrence. As CT was performed 3 times for 3 shoulders including primary injury and the second episode of instability (first recurrence), there were 50 CT evaluations. Morphological changes between the initial CT evaluation at primary instability and the second CT evaluation at first recurrence were investigated for 25 shoulders, with the mean interval since initial CT being 9.8 months (range, 2-23 months). Changes between initial CT evaluation and final CT evaluation after ≥2 recurrences were also investigated for 25 shoulders, while the mean number of instability episodes including primary instability was 8.0 (range, 3-40) and the mean interval since initial CT was 18.5 months (range, 5-56 months). RESULTS: At primary instability, the prevalence of Hill-Sachs lesions (66.0%) was almost double that of glenoid defects (34.0%), but their prevalence was different between shoulders with primary subluxation (42.3% and 23.8%, respectively) and those with primary dislocation (84.7% and 42.3%, respectively). After recurrence, glenoid defects became significantly more frequent (at first recurrence, 72%; after ≥2 recurrences, 76%), while Hill-Sachs lesions showed a smaller increase (88% and 80%, respectively), so there was no difference between the prevalence of the 2 lesions. The sizes of glenoid defects and Hill-Sachs lesions also enlarged after recurrence, and large bone defects were frequently recognized after recurrence. While bipolar bone loss was not so frequent at primary instability (29.8%), bipolar bone loss increased significantly after recurrence (at first recurrence, 72%; after ≥2 recurrences, 72%). All Hill-Sachs lesions were on track at primary instability, but off-track lesions were recognized in 3 of 47 shoulders (6.4%) after recurrence. CONCLUSION: In most shoulders with recurrent instability, a Hill-Sachs lesion developed first, followed by a glenoid defect, leading to bipolar bone loss. Off-track Hill-Sachs lesions were detected only after recurrence.

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.

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.

Mechanical Properties of an Adjustable-Loop Cortical Suspension Device for Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Various biomechanical properties of adjustable-loop cortical suspension devices have been observed among previous studies in which different experimental conditions were used to test each of these devices. However, no studies have investigated the biomechanical properties of single adjustable-loop cortical suspension devices under different cyclic loading protocols. It is necessary to clarify the problems associated with using this device and detect the best method of using it in the clinical setting. HYPOTHESIS: The elongation of the loop of an adjustable-loop cortical suspension device with cyclic loading would be smaller with (1) an increase in the lower force limit and (2) lower speeds of cyclic loading. STUDY DESIGN: Controlled laboratory study. METHODS: Eighteen anterior cruciate ligament (ACL) adjustable-loop cortical suspension devices were tested under the following 3 cyclic loading protocols in a device-only model. Protocol A included cyclic loading between 10 and 50 N at 50 mm/min for 500 cycles. The upper force limit was then increased by 25-N increments every 500 cycles up to 250 N, for a total of 4500 cycles. Protocol B included cyclic loading between 30 and 50 N at 50 mm/min for 500 cycles. The upper force limit was then increased to 250 N, for a total of 4500 cycles, in the same manner as protocol A. Protocol C included cyclic loading between 30 and 50 N at 25 mm/min for 500 cycles. The upper force limit was then increased to 250 N, for a total of 4500 cycles, in the same manner as protocol A. RESULTS: The elongation after 4500 cycles was 36.1, 18.5, and 8.6 mm for protocols A, B, and C, respectively. There were significant differences among the 3 protocols, with protocol C showing the smallest elongation with cyclic loading. The elongation in each group progressed with each 25-N cyclic load increment. CONCLUSION: The adjustable-loop cortical suspension device showed a smaller elongation of the loop with increases in the lower force limit and with lower cyclic loading speeds. CLINICAL RELEVANCE: Care should be taken during rehabilitation after anatomic ACL reconstruction using adjustable-loop cortical suspension devices with a low initial tension at graft fixation. Slow and less intense exercises may be more desirable in the early stages of healing.

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.

Postoperative Recurrence of Instability Due to New Anterior Glenoid Rim Fractures After Arthroscopic Bankart Repair.

BACKGROUND: Computed tomography (CT) sometimes reveals a new fracture of the anterior glenoid rim in patients with postoperative recurrence of instability after arthroscopic Bankart repair using suture anchors, but there have been few previous reports about such fractures. HYPOTHESIS: The placement of a large number of suture anchors during arthroscopic Bankart repair might be associated with a new glenoid rim fracture. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Screw-in metal suture anchors were used until June 2011 and suture-based soft anchors from July 2011. A follow-up of at least 2 years was conducted for 128 shoulders treated using metal anchors (metal anchor group) and 129 shoulders treated using soft anchors (soft anchor group). The frequency and features of new glenoid rim fractures were investigated, and the influence of the number of suture anchors and other factors on fractures was also assessed. RESULTS: There were 19 shoulders (14.8%) with postoperative recurrence in the metal anchor group and 23 shoulders (17.8%) in the soft anchor group. Among 37 shoulders evaluated by CT at recurrence, a new glenoid rim fracture was detected in 13 shoulders (35.1%; 5 shoulders in the metal anchor group and 8 shoulders in the soft anchor group). A fracture at the anchor insertion site was recognized in 4 shoulders from the metal anchor group and 6 shoulders from the soft anchor group, although linear fractures connecting several anchor holes were only seen in the soft anchor group. While new glenoid fractures occurred regardless of the number of suture anchors used, new fractures were significantly more frequent in teenagers at surgery and in junior high school or high school athletes. Such fractures did not only occur in contact athletes but were also found in overhead athletes. CONCLUSION: Postoperative recurrence of instability associated with a new glenoid rim fracture along the suture anchor insertion site was frequent after arthroscopic Bankart repair. These fractures might be related to placing multiple soft suture anchors in a linear arrangement.

Biomechanical characteristics of the anatomic rectangular tunnel anterior cruciate ligament reconstruction with a bone-patellar tendon-bone graft.

PURPOSE: To clarify 1) the force sharing between two portions of BTB graft in anatomic rectangular tunnel (ART) reconstruction and 2) the knee stability in ART technique under anterior tibial load. METHODS: Eleven fresh cadaveric knees were used. First, anterior-posterior (A-P) laxity was measured with Knee Laxity Tester® in response to 134 N of A-P tibial load at 20° on the normal knees. Then ART ACL reconstruction was performed with a BTB graft. For graft, the patellar bone plug and tendon portion was longitudinally cut into half as AM and PL portions. After the tibial bone plug was fixed at femoral aperture, AM/PL portions were connected to the tension-adjustable force gauges at tibial tubercle, and were fixed with 10 N to each portion at 20°. Then the tension was measured 1) under anterior tibial load of 134 N at 0, 30, 60, and 90°, and 2) during passive knee extension from 120 to 0°. Next the graft tension was set at 0, 10, 20, 30, or 40 N at 20°, and the A-P laxity was measured by applying A-P load of 134 N. By comparing the laxity for the normal knee, the tension to restore the normal A-P laxity (LMP) was estimated. RESULTS: The AM force was significantly smaller at 0° and larger at 90° than the PL force under anterior load, while the force sharing showed a reciprocal pattern. During knee extension motion, the tension of both portions gradually increased from around 5 N to 20-30 N with knee extended. And the LMP was 1.6 ± 1.0 N with a range from 0.3 to 3.5 N. CONCLUSION: The pattern of force sharing was similar to that in the normal ACL in response to anterior tibial load and during passive knee extension motion. LMP in this procedure was close to the tension in the normal ACL. LEVEL OF EVIDENCE: Level IV, a controlled-laboratory study.

Biomechanical testing of transcapsular meniscal repair.

BACKGROUND: All of previous biomechanical studies on meniscal repair have examined the meniscus itself without synovial membrane and capsule, although in the clinical setting, the meniscal repair is generally performed including capsule. Therefore, biomechanical properties of transcapsular meniscal repair are unclear. Thus, this study aimed to clarify the biomechanical properties of transcapsular meniscal repair. METHODS: In 70 porcine femur-medial meniscus-tibia complexes with capsules, longitudinal meniscal tears were repaired using different suture techniques (inside-out or all-inside technique), suture methods (vertical or horizontal methods), and numbers of sutures (single or double). A cyclic loading test between 5 and 20 N for 300 cycles was performed followed by a load-to-failure test. RESULTS: Tears repaired by the all-inside technique presented significantly larger widening (0.88 ± 0.38 mm) than those by the inside-out technique (0.51 ± 0.39 mm) during the cyclic loading test (P = 0.035). The horizontal suture presented significantly lower ultimate failure load (62.5 ± 15.5 N) in the all-inside technique than in the vertical suture (79.7 ± 13.0 N; P = 0.018). The stacked suture had a significantly higher failure load (104.6 ± 12.5 N) than the parallel suture (83.3 ± 12.6 N; P = 0.001). Furthermore, the double suture presented significantly higher failure loads (83.3 ± 12.6 N and 104.6 ± 20.4 N) than the single suture with both inside-out (58.8 ± 8.3 N; P = 0.001) and all-inside (79.7 ± 13.0 N; P = 0.022) techniques. CONCLUSIONS: Upon comparison of the suture techniques, the inside-out technique provided a more stable fixation at the repair site than the all-inside technique during the cyclic test. Among the suture methods, the vertical suture had more desirable biomechanical properties than the horizontal suture as demonstrated by smaller widening during the cyclic test and the larger load to failure. The stacked suture created a stronger fixation than the parallel suture. In terms of the number of sutures, the double suture had superior biomechanical properties compared with the single suture.

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.

Effects of suture site or penetration depth on anchor location in all-inside meniscal repair.

BACKGROUND: To evaluate the effects of suture site or penetration depth on anchor location in all-inside meniscal repair. METHODS: Eight fresh-frozen cadaveric knees were evaluated after meniscal repair using eight FasT-Fix360 (FF360) devices (Smith & Nephew Endoscopy, Andover, MA) (16 anchors) for each knee. The penetration depth was 14mm, the distance same from the periphery to insertion point, in four knees (Group A) and that in the remaining four knees (Group B) was 18mm. The anchor location in two groups was evaluated after attentive dissection. RESULTS: Of 32 anchors for the medial meniscus, 94% were on the capsule, including the superficial medial collateral ligament (sMCL) in both groups. For the lateral meniscus, 47% anchors in Group A and 44% anchors in Group B were on the capsule. Total three anchors were over the lateral collateral ligament (LCL), whereas 15 anchors were behind the popliteus tendon (POP). Although all three anchors settled in the subcutaneous fat were in Group B, no significant difference was observed in anchor location between two groups. CONCLUSIONS: Secure fixation to thin membranous tissue can be achieved for the medial meniscal repair using FF360, while some were located in/on bunchy LCL or POP in lateral meniscal repair. Only anchors with additional four-millimeter penetration depth were in the subcutaneous fat, although there was no effect of the penetration depth to anchor location. Clinically, for lateral meniscal repair, penetrating toward POP/LCL should be avoided and four-millimeter deeper penetration depth might be a risk for the subcutaneous irritation.

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.

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.

Symptomatic calcification of the anterior cruciate ligament: A case report.

We report a rare case of symptomatic calcification of the ACL. A 31-year-old man complained of severe knee pain with restriction of knee motion from 30° to 130° for a week. Plain radiographs and multi-planar CT revealed calcification within the intercondylar notch with no osteoarthritic changes. MRI revealed a low signal intensity mass near the intact ACL. The ACL appeared bulged by arthroscopy and white and creamy fluid exuded from the partially excised synovial membrane. Pain subsided immediately postoperatively. Histologically, the calcific deposit near the ACL showed negligible degenerative changes and resembled calcifying tendinitis of the rotator cuff. Although calcific deposits rarely affect the knee joint, calcification of the ACL should be included in differential diagnoses for acute knee pain and restricted range of motion such as mechanical locking. This case illustrates that arthroscopic removal of the deposits can be effective.