Bone-patellar tendon-bone autograft is associated with a higher rate of return to preinjury levels of performance in high-level athletes than anterior cruciate ligament reconstruction using hamstring autograft.

PURPOSE: Return to preinjury levels of performance (RTP) is the main goal after anterior cruciate ligament reconstruction (ACL-R) for athletes when ACL graft rupture is a career-threatening event. The purpose of this study was to elucidate the associated factors for RTP and subsequent ACL injury after ACL-R using bone-patellar tendon-bone (BPTB) or hamstring (HT) autograft in high-level athletes with a minimum postoperative follow-up of 24 months. METHODS: This retrospective study included 157 patients who had preinjury Tegner activity level of 9 and underwent primary ACL-R using BPTB (average age, 16.9 years; 35 males and 36 females) or HT (average age, 17.2 years; 49 males and 37 females). The mean follow-ups were 33.6 months in BPTB and 44.5 months in HT, respectively. The data were obtained based on routine clinical follow-ups and telephone interviews performed by the surgeon. Multivariate logistic regression analysis was conducted to determine the association of patient variables with RTP and subsequent ACL injury. RESULTS: Ninety-nine patients (63.1%) were able to RTP. The rate of RTP in BPTB (74.6%) was significantly higher than that of HT (53.5%) (p < 0.05). The overall average timing of RTP after ACL-R was 10.0 months while that was significantly earlier in BPTB (9.7 months) than in HT (10.5 months) (p < 0.05). Twenty-three (14.6%) and 21 patients (13.4%) had ACL graft ruptures and ACL injuries in the contralateral knees, respectively. Multivariate analyses showed that BPTB (odds ratio [OR], 2.590; 95% confidence interval [CI], 1.300-5.160; p = 0.007) was associated with a higher potential for RTP after ACL-R. The incidence of ACL graft rupture after ACL-R decreased with BPTB (OR, 0.861; 95% CI, 0.770-0.962; p = 0.009). CONCLUSIONS: The use of BPTB autograft was associated with a higher rate of RTP and a lower incidence of ACL graft rupture compared to ACL-R using HT autograft. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Quadriceps Tendon With Bone Autograft Has Better Stability and Magnetic Resonance Imaging Maturation Than Hamstring Tendon Autograft After Anterior Cruciate Ligament Reconstruction in Patients With Knee Hyperextension.

PURPOSE: To compare the clinical outcomes of anterior cruciate ligament (ACL) reconstruction between methods using quadriceps tendon with bone (QTB) and hamstring tendon (HT) in patients with hyperextension of the knee. METHODS: The medical records of patients with knee hyperextension greater than 8° who underwent arthroscopic ACL reconstruction between October 2010 and October 2020 with follow-up for at least 2 years (median, 3 years; interquartile range [IQR], 2.0-4.6 years) were retrospectively reviewed. Side-to-side difference in anterior translation, pivot-shift test grade, Lysholm score, and graft intensity using the Howell grade on magnetic resonance imaging at final follow-up were compared between the QTB and HT groups. RESULTS: The HT and QTB groups consisted of 42 patients and 21 patients, respectively. The overall mean age was 21.5 years (range, 14-48 years), and the median Tegner Activity Scale score was 6 (range, 3-9). Postoperatively, the median side-to-side difference in anterior translation was 1.75 mm (IQR, 1-3 mm) in the HT group and 1.0 mm (IQR, 0-1.75 mm) in the QTB group (P = .01). Pivot-shift testing showed grade 0 in 74.7%, grade 1 in 18.7%, and grade 2 in 6.6% of patients in the HT group and grade 0 in 85.7% and grade 1 in 14.3% of those in the QTB group (P = .03). The median postoperative Lysholm score was 99 in both groups. Graft signal intensity showed a significant between-group difference: grade I in 52%, grade II in 36%, and grade III in 12% of patients in the HT group versus grade I in 85.7%, grade II in 9.5%, and grade III in 4.8% of those in the QTB group (P = .03). CONCLUSIONS: In patients who underwent ACL reconstruction for hyperextension of the knee, QTB yielded better clinical outcomes than HT with respect to anterior stability, rotational stability, and graft signal intensity on median 2-year follow-up magnetic resonance imaging. LEVEL OF EVIDENCE: Level III, retrospective case-control study.

Analyses of associated factors with concomitant meniscal injury and irreparable meniscal tear at primary anterior cruciate ligament reconstruction in young patients.

Purpose: Although several factors related to the concomitant meniscal injury at anterior cruciate ligament reconstruction (ACL-R) have been investigated in a general population, few studies have identified the risk factors of meniscal tear severity in young patients in which the majority of ACL tears occur. The purpose of this study was to analyze the associated factors with meniscal injury and irreparable meniscal tear and the timeline for medial meniscal injury at ACL-R in young patients. Methods: A retrospective analysis of young patients (13 to 29 years of age) who underwent ACL-R by a single surgeon from 2005 to 2017 was conducted. Predictor variables (age, sex,body mass index [BMI], time from injury to surgery [TS], and pre-injury Tegner activity level) for meniscal injury and irreparable meniscal tear were analyzed with multivariate logistic. Results: Four hundred and seventy-three consecutive patients with an average of 31.2 months post-operative follow-up were enrolled in this study. The risk factors for medial meniscus injury were TS (<= 3 months) (odds ratio [OR], 3.915; 95% CI, 2.630-5.827; P < .0001) and higher BMI (OR, 1.062; 95% CI, 1.002-1.125; P = 0.0439). The presence of irreparable medial meniscal tears correlated with higher BMI (OR, 1.104; 95% CI, 1.011-1.205; P = 0.0281). Conclusion: An increased time from ACL tear to surgery of 3 months was strongly associated with an increased risk of medial meniscus injury, but not related to irreparable medial meniscal tear at primary ACL reconstruction in young patients. Level of Evidence: Level IV.

Bone-patellar tendon-bone autograft and female sex are associated with the presence of cyclops lesions and syndrome after anterior cruciate ligament reconstruction.

PURPOSE: Associated risk factors for the development of cyclops lesions have been little. Investigated, because most previous studies have limited their research to cases with symptomatic cyclops lesions (cyclops syndrome). The purpose of this study was to evaluate the presence of cyclops lesions using magnetic resonance image (MRI) at 6 and 12 months after anterior cruciate ligament reconstruction (ACL-R), and to investigate the associated risk factors of cyclops lesions and syndrome. METHODS: A retrospective analysis of patients who underwent ACL-R using bone-patellar tendon-bone (BTPB) or hamstring tendon autograft from 2008 to 2017 was conducted. Predictor variables (age, sex, body mass index [BMI], time from injury to ACL-R, preinjury Tegner activity score, graft, meniscal and cartilage injury, and notch width index on MRI for the presence of cyclops lesions and syndrome were analyzed with multivariate logistic regression. RESULTS: Four hundred and fifty-five patients (225 males and 230 females) were enrolled. One hundred and four patients (22.9%) had cyclops lesions, and all cyclops lesions were detected on MRI at 6 months post-operatively. In addition, 20 patients (4.4%) had cyclops syndrome which means that these were symptomatic cases. The risk factors for presence of cyclops lesions were BPTB autograft (OR = 2.85; 95% CI 1.75-4.63; P < 0.001) and female sex (OR = 2.03; 95% CI 1.27-3.25; P = 0.003). The presence of cyclops syndrome increased with graft (BPTB) (OR = 18.0; 95% CI 3.67-88.3; Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation P < 0.001), female sex (OR = 3.27; 95% CI 1.07-10.0; P = 0.038), and increased BMI (OR = 1.21; 95% CI 1.05-1.39; P = 0.008). CONCLUSIONS: All cyclops lesions were detected 6 months after ACL-R, and the majority of them were asymptomatic. BPTB autograft and female sex were the significant risk factors for the presence of cyclops lesions and syndrome. In addition, increased BMI was associated with a higher risk of developing cyclops syndrome. When BPTB autograft is used for a female patient, full active knee extension should be encouraged in the early period after ACL-R to prevent cyclops lesion formation. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Transplantation of Parathyroid Hormone-Treated Achilles Tendon Promotes Meniscal Regeneration in a Rat Meniscal Defect Model.

BACKGROUND: Autologous tendon grafts are used for meniscal reconstruction of surgically removed knee joint meniscus. However, as meniscal reconstruction cannot prevent the progression of cartilage degeneration, additional procedures that confer meniscus-like histological properties to the transplanted tendon are required for improved outcomes. HYPOTHESES: Parathyroid hormone (PTH)(1-34) induces cartilage formation in the rat tendon, and transplantation of PTH-treated tendon promotes meniscal regeneration. STUDY DESIGN: Controlled laboratory study. METHODS: Rat Achilles tendon-derived cells were cultured with or without PTH for 28 days and stained with Alcian blue to determine chondrogenic differentiation. After 14 and 28 days of incubation, gene expression was assessed using quantitative real-time polymerase chain reaction. In an in vivo study, rat Achilles tendon was injected with PTH and then transplanted onto a medial meniscal defect. Macroscopic and histological assessments of the regenerated meniscus and of cartilage degeneration in the tibial plateau were performed at 4 and 8 weeks after surgery. RESULTS: In vitro, PTH-treated cells showed better staining with Alcian blue than the control (normal medium) group. PTH1R, Col2a1, Sox9, and RUNX2 were significantly upregulated in PTH-treated cells (P < .05). Macroscopically, the in vivo results revealed more prominent meniscal coverage and lesser progression of articular cartilage degeneration in the PTH group than in the phosphate-buffered saline-injected group. Histologically, toluidine blue staining revealed metachromasia in the PTH-injected tissue at 4 and 8 weeks. The PTH-treated regenerated meniscus showed positive immunostaining for type II collagen in the area exhibiting metachromasia. Moreover, PTH-treated tendon had an enhanced histological score compared with the untreated group at 4 and 8 weeks (P < .05). CONCLUSION: PTH(1-34) induced cartilage formation in the rat tendon. Transplantation of PTH(1-34)-treated Achilles tendon in a rat meniscal defect model induced meniscal regeneration and preserved knee articular cartilage. Macroscopically, PTH groups showed a greater coverage of the regenerated meniscus. Histologically, the regenerated meniscus had higher cartilaginous matrix content in rats transplanted with PTH-treated tendons. PTH(1-34) stimulated tendon-derived cells to promote chondrogenic differentiation. CLINICAL RELEVANCE: Meniscal transplantation using PTH-injected autologous tendon grafts might promote meniscal regeneration and prevent progression of cartilage degeneration by stimulating chondrogenic differentiation of tendon-derived cells.

Comparison of the Healing Outcomes of Conservative Treatment for Stable Juvenile Osteochondritis Dissecans of the Lateral Femoral Condyle With Normal Lateral Meniscus and Incomplete Discoid Lateral Meniscus.

BACKGROUND: This study aimed to compare the healing outcomes of conservative treatment for osteochondritis dissecans (OCD) of the lateral femoral condyle with normal lateral meniscus and incomplete discoid lateral meniscus (DLM). METHODS: Forty-four knees in 37 juvenile patients (mean age 9.9 y) with stable OCD and whose lateral meniscus shape was normal or incomplete DLM were enrolled. All patients underwent conservative treatment with physical activities prohibited. For each lateral meniscus group, patient demographics including pretreatment Tegner activity scale, OCD stage, and Lysholm score, radiographic healing status; complete or incomplete healing at 3 months, 6 months, and 1 year, time to complete healing and post-treatment clinical scores were evaluated. RESULTS: There were 21 (47.8%) and 23 (52.3%) knees with normal menisci and incomplete DLM, respectively. At 3 months, 6 months, and 1 year after conservative treatment, healed OCD status was noted in 3 (14.3%), 12 (57.1%), and 19 (90.5%) knees of the normal type and in 3 (13.0%), 12 (52.2%), and 20 (86.9%) knees of the incomplete DLM type, respectively (P>0.05). The mean time to healing in each group was 198 and 181 days, respectively. No significant differences in terms of OCD healing rate at each time, time to healing, and post-treatment clinical scores were found between the groups. CONCLUSION: No significant differences in the OCD healing rate or time to healing were found between the normal and incomplete DLM type. Therefore, treatment strategy for OCD with stable and asymptomatic incomplete DLM should be the same as that for those occurring with a normal meniscus.

Risk Factors Related to the Presence of Meniscal Injury and Irreparable Meniscal Tear at Primary Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Few studies have attempted to identify risk factors associated with irreparable meniscal tears at anterior cruciate ligament reconstruction (ACLR) and to describe follow-up data, such as the failure rate, after meniscal repair. PURPOSE: To investigate the associations of age, sex, body mass index (BMI), time to surgery (TTS), and preinjury Tegner score with the presence of meniscal injuries and irreparable meniscal tears at primary ACLR. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A retrospective review was performed on 784 patients who underwent primary ACLR by a single surgeon between 2005 and 2017 (406 men and 378 women; mean age, 25.8 years; mean BMI, 23.1; median TTS, 3 months; median preinjury Tegner score, 7). All patients had a minimum follow-up of 12 months (mean postoperative follow-up, 33.0 months). Multivariate logistic regression analysis was conducted to determine the association of patient variables with the presence of meniscal injuries and irreparable meniscal tears during primary ACLR. RESULTS: The risk factor for medial meniscal injuries was TTS ≥3 months (odds ratio [OR], 4.213; 95% CI, 3.104-5.719; P < .001). The presence of irreparable medial meniscal tears increased with older age (OR, 1.053; 95% CI, 1.024-1.084; P < .001), higher BMI (OR, 1.077; 95% CI, 1.003-1.156; P = .042), and TTS ≥3 months (OR, 1.794; 95% CI, 1.046-3.078; P = .034). On multivariate analysis, none of the variables were significantly associated with lateral meniscal injuries and irreparable meniscal tears. The failure rate, defined as patients who needed additional medial meniscal surgery after medial meniscal repair, was 4.6%. CONCLUSION: Time from ACL injury to reconstruction of ≥3 months was strongly associated with medial meniscal injuries and irreparable medial meniscal tears at primary ACLR. Older age and increased BMI were also risk factors for the presence of irreparable medial meniscal tears at ACLR.

Risk factors for postoperative graft laxity without re-injury after double-bundle anterior cruciate ligament reconstruction in recreational athletes.

BACKGROUND: Although high activity is a risk factor for graft failure after anterior cruciate ligament (ACL) reconstruction, the risk factors for postoperative laxity after ACL reconstruction in recreational athletes are unknown. METHODS: We enrolled 91 patients (40 males, 51 females; mean age 29.2 years; mean follow-up 4.3 years) who scored ≤ 6 on the Tegner activity scale, underwent double-bundle ACL reconstruction between 2010 and 2018, and did not experience re-injury. In the stable group (75 patients, <3.0 mm side-to-side difference (SSD) in anterior translation, grade 0 or 1 pivot shift 1 year after surgery) and unstable group (16 patients, ≥3.0 mm SSD, ≥grade 2 pivot shift), multivariate logistic regression analyses adjusted for factors showing P ≤ 0.3 on univariate analysis assessed risk factors for graft laxity. Lysholm score and graft intensity on MRI (Howell grade) were compared at final follow-up. RESULTS: Mean SSD in anterior translation was 0.7 mm (stable group) and 3.3 mm (unstable group). Pivot shift grades were 0 (88%) and 1 (12%) in the stable group, and 0 (12.5%), 1 (50%), and 2 (37.5%) in the unstable group. Multivariate regression analyses showed that younger age and knee hyperextension were significant risk factors for graft laxity (P = 0.018 and 0.0016; cutoffs 18 years old and 8°, respectively). Lysholm scores in both groups were comparable, but graft intensity on MRI demonstrated significantly worse Howell grade in the unstable group (P = 0.002). CONCLUSION: Younger age and knee hyperextension were risk factors for postoperative graft laxity without re-injury in recreational athletes.

Arthroscopic Repair for Parrot Beak Tear of Lateral Meniscus with Reduction Suture and Inside-Out Technique.

Parrot beak tear is a white-white meniscal injury that often occurs in isolated injuries. Partial meniscectomy for parrot beak tears is often recommended, owing to the avascular zone; however, partial meniscectomy, especially with the lateral meniscus, has a high failure rate for return to sports, leading to residual meniscus extrusion and lateral compartment osteoarthritis. Thus, we have developed a repair technique to preserve the parrot beak tear of the avascular zone. This is a modification of the inside-out repair with additional reduction sutures. We recommend this procedure as a technique for repairing avascular parrot beak tears of the lateral meniscus.

Factors Related to Postoperative Osteochondritis Dissecans of the Lateral Femoral Condyle After Meniscal Surgery in Juvenile Patients With a Discoid Lateral Meniscus.

PURPOSE: The purpose was to assess the incidence of postoperative osteochondritis dissecans (OCD) and the related epidemiologic factors following meniscal surgery for juvenile discoid lateral meniscus (DLM). METHODS: The study was a retrospective review of 103 knees in 89 patients with a mean age of 12.1 years who underwent arthroscopic meniscal surgery for DLM. Mean follow-up was 4.2 years. The surgical procedures were either saucerization, saucerization with repair or subtotal meniscectomy, depending on the type of DLM tear. Postoperative OCD lesions were identified radiographically. Age, sex, weight, Lysholm score, Tegner activity scale, exercise frequency, and surgical procedure were compared between the postoperative OCD diagnosis group and non-OCD control group. RESULTS: Postoperative OCD was diagnosed in 8/103 (7.8%) knees following DLM surgery. The incidence of postoperative OCD was significantly greater for patients age less than 10 years old, and male sex, low weight, Lysholm score, Tegner activity scale preinjury and after returning to sports, and exercise frequency per week on univariate analyses. On multivariate analyses, postoperative OCD occurred more commonly with subtotal meniscectomy than with saucerization or saucerization with repair, and in patients less than 11 years of age. Receiver operating characteristic curve analysis revealed a cutoff value of age at surgery of 10 years. CONCLUSIONS: Subtotal meniscectomy and patients younger than 10 years at the time of surgery are at greater risk for postoperative OCD. To decrease this risk, if possible, we recommend performing saucerization or saucerization with repair in patients undergoing surgery for DLM. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Abnormal displacement of discoid lateral meniscus with snapping knee detected by full extension and deep flexion MRI: Report of two cases.

We evaluated the abnormal displacement of a complete discoid lateral meniscus in two patients with symptoms of a large popping sound during knee flexion and extension, so-called "snapping", and no displacement of the discoid meniscus on routine Magnetic Resonance Imaging (MRI) analysis. MRI images indicated an anterocentral shift of the lateral discoid meniscus on knee deep flexion in one case and a posterocentral shift of the meniscus on knee full extension in the other case. Abnormal meniscal instability was confirmed under arthroscopy in both knees. After arthroscopic partial meniscectomy, one case of posterior horn instability was treated with an inside-out arthroscopic technique, whereas the other case of anterior horn instability was treated with an all-inside repair technique. We conclude that the symptom of a large popping sound during knee motion may indicate abnormal displacement of a complete discoid lateral meniscus and that further MRI analyses on knee full extension and deep flexion may reveal discernible meniscal displacement.

Assessment of Meniscal Healing Status by Magnetic Resonance Imaging T2 Mapping After Meniscal Repair.

BACKGROUND: Although the sensitivity and specificity of magnetic resonance imaging (MRI) for the diagnosis of primary meniscal tears are high, these values are lower for the assessment of healing status of repaired menisci. PURPOSE: To compare the accuracy of MRI T2 mapping and conventional MRI in assessing meniscal healing after repair. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Patients who underwent meniscal repair with concurrent anterior cruciate ligament reconstruction between 2012 and 2016 and had a follow-up second-look arthroscopy were enrolled. The patients were divided into healed and incompletely/not healed groups based on the second-look arthroscopy findings. For the repaired menisci, the following were compared between the groups, (1) Stoller and Crues classification on conventional MRI with a proton density-weighted fat-saturated sequence and (2) the remaining colored meniscal tear line on T2 mapping coincident with the high signal line showing the primary tear on conventional MRI were compared. The change of T2 relaxation time (ΔT2) of the colored meniscal tear line pre- to postoperatively was compared between the groups. The mean T2 relaxation time of the whole area of the postoperative meniscus at each slice was also compared with that of control menisci to assess the whole quality of the repaired meniscus. RESULTS: A total of 26 menisci from 24 knees were assessed (16 healed menisci, 10 incompletely/not healed menisci). According to the Crues classification on conventional MRI, 8 of 16 healed menisci and 3 of 10 incompletely/not healed menisci improved from grade 3 to 2, with there being no significant difference between the groups (P = .43). However, the colored meniscal tear line remained in only 3 of the 16 healed menisci as compared with 9 of the 10 incompletely/not healed menisci, and the presence of this colored line allowed differentiation between healed menisci and incompletely/not healed menisci (sensitivity, 81.3%; specificity, 90.0%; odds ratio, 39.0; P = .001). The mean (SD) ΔT2 was -31.1 ± 3.2 and -19.9 ± 4.4 ms in the healed and incompletely/not healed groups, respectively (P < .001). Receiver operating characteristic curve analysis showed a cutoff ΔT2 value of -22.3 ms for separation of meniscal healing (P < .001). The T2 relaxation times of the whole area of the repaired menisci were 31.7 ± 3.4 and 32.8 ± 3.8 ms in the healed and incompletely/unhealed groups, respectively (P = .69), with these values being significantly longer than the 26.9 ± 2.2 ms in the controls (P < .001). CONCLUSION: MRI T2 mapping allowed the differentiation of healing status after meniscal repair, with high sensitivity and specificity as compared with conventional MRI.

Donor Site Evaluation After Osteochondral Autograft Transplantation for Capitellar Osteochondritis Dissecans.

BACKGROUND: Osteochondral autograft transplantation (OAT) for capitellar osteochondritis dissecans (OCD) requires harvesting of tissue from the asymptomatic knee joint. However, donor site morbidity (DSM) in such cases remains unclear. PURPOSE: To evaluate DSM and postoperative radiographic findings in patients undergoing OAT for advanced capitellar OCD. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Eighty-six juvenile athletes underwent OAT for advanced capitellar OCD. The 2000 International Knee Documentation Committee subjective score, rate of return to sports, and symptoms in the donor knee were assessed at a mean follow-up of 86 months (range, 28-185 months). Additionally, 49 of the 86 patients were assessed by radiographic and magnetic resonance imaging (MRI) findings of the knee donor site. DSM was defined according to the usual criterion (persistent symptoms for >1 year or the need for subsequent intervention) and a stricter criterion (the presence of any symptoms, such as effusion, patellofemoral complaints, crepitation, unspecified disturbance, stiffness, pain/instability during activities, and osteoarthritic change). The stricter criterion was also used to allocate patients into a DSM group and a no-DSM group. RESULTS: Two and 11 patients were determined to have DSM according to the usual and stricter criteria, respectively. All patients returned to the competitive level of their sports. The mean International Knee Documentation Committee score was 99.0. MRI findings showed abnormal signal intensity in 17 patients (35%) and hypertrophic changes in 11 patients (22%) at the donor harvest sites. The MOCART (magnetic resonance observation of cartilage repair tissue) score was higher in the no-DSM group (mean, 68.2) than in the DSM group (mean, 52.9) (P = .027). CONCLUSION: OAT for juvenile athletes with advanced capitellar OCD provided good clinical outcomes. The DSM rate was relatively low (2.3%) with the usual criterion but high (12.8%) with the stricter criterion. MRI showed an abnormal signal intensity and hypertrophy in some cases.

Shallow knee flexion angle during femoral tunnel creation using modified transtibial technique can reduce femoral graft bending angle in ACL reconstruction.

PURPOSE: The purpose of this study was to compare femoral graft bending angle between patients with femoral tunnel reamed at less than 80° of knee flexion and those with 80° and above in anatomical anterior cruciate ligament (ACL) reconstruction using modified transtibial technique. METHODS: Forty-eight patients who underwent ACL reconstruction using bone-patellar-tendon-bone autograft in modified transtibial technique and CT scan at 1 week postoperatively were included in this study. A femoral guidewire insertion into aimed femoral position at the medial wall of the femoral lateral condyle was started at about 75° of knee flexion. When the tip of the guidewire was blown out into femoral posterior wall, the guidewire was inserted again after increasing knee flexion angle. Distance from femoral tunnel exit on the femoral lateral cortex-femoral posterior cortex (Distance-E) was measured on postoperative lateral radiograph. Femoral and tibial tunnel position was measured on 3-D CT images. In addition, femoral graft bending angle was measured on reconstructed 2-D CT images. Patients were divided into two groups depending on whether femoral tunnel was created at less than 80° of knee flexion (group A) or 80° or more (group B). RESULTS: There were 32 patients in group A and 16 patients in group B, respectively. Average knee flexion angle was 77.2° [standard deviation (SD) 1.6] in group A and 83.6° (SD 2.4) in group B, respectively (p < 0.05). Average Distance-E was 5.1 mm (SD 2.6) in group A and 6.6 mm (SD 3.8) in group B, respectively. There was no significant difference in the femoral and tibial tunnel position between group A and B. Femoral graft bending angle was significantly smaller in group A [average angle: 50.9° (SD 6.6)] than in group B [average angle: 55.0° (SD 6.6)] (p < 0.05). CONCLUSIONS: Anatomical femoral tunnel was able to be created at less than 80° of knee flexion in two-thirds of patients. Shallower flexion angle (less than 80°) provided gentler femoral graft bending angle compared to 80° or more of knee flexion. Therefore, femoral tunnel creation in modified transtibial technique should be started at between 75° and 80° of knee flexion to reduce femoral graft bending angle. Shallow knee flexion angle during femoral tunnel creation using modified transtibial technique can reduce femoral graft bending angle and may lead to better clinical outcomes in ACL reconstruction. LEVELS OF EVIDENCE: Retrospective comparative study, Level III.

Predictive factors for osteochondritis dissecans of the lateral femoral condyle concurrent with a discoid lateral meniscus.

PURPOSE: Osteochondritis dissecans (OCD) of the lateral femoral condyle is relatively rare, and it is often reported in combination with discoid lateral meniscus. However, little is known about the mechanism underlying this connection. Predictive factors for OCD coinciding with discoid lateral meniscus in Japanese children and adolescents were assessed. METHODS: During 2000-2015, 152 knees in 133 patients aged 5-15 years were diagnosed with symptomatic complete discoid lateral meniscus. Patients were evaluated using radiography and magnetic resonance imaging (MRI). OCD was radiographically graded using the Brückl classification. Based on Ahn's MRI classifications, discoid lateral meniscus was divided into four types of meniscal shift: no shift (N), anterocentral (AC), posterocentral (PC), or central (C). Relationships between OCD and patient sex, age and Ahn's shift type were analysed. RESULTS: OCD of the lateral femoral condyle was associated with discoid lateral meniscus in 22 (14.5%) of 152 knees. OCD was classified as Brückl's stage 1 in 5 knees, stage 2 in 12, stage 3 in 3, stage 4 in 1, and stage 5 in 1. OCD was found in 12 of 96 knees (12.5%) with type N meniscal shift, 4 of 24 knees (16.7%) with type AC, 0 of 21 knees (0%) with type PC, and 6 of 11 knees (54.5%) with type C. Multivariate logistic regression analysis showed that males had a significantly increased odds ratio (OR) [14.8; 95% confidence interval (CI) 2.6-83.4]. Those aged 5-11 years had a significantly higher OR (12.5; 95% CI 2.8-55.9) than those aged 12-15 years. The OR for type C coinciding with OCD was significantly elevated (13.4; 95% CI 2.3-78.7). CONCLUSIONS: Concurrent OCD was found in 22 (14.5%) of 152 knees with discoid lateral meniscus. Male sex, young age (5-11 years), and having a type C meniscal shift of the discoid lateral meniscus as shown by MRI were found to be predictive factors for OCD of the LFC. LEVEL OF EVIDENCE: III.

Risk Factors Associated With Knee Joint Degeneration After Arthroscopic Reshaping for Juvenile Discoid Lateral Meniscus.

BACKGROUND: Although arthroscopic meniscal reshaping for discoid lateral meniscus (DLM) has better outcomes than total or subtotal meniscectomy, degenerative changes on radiographs are still seen in some patients with meniscal reshaping. PURPOSE: To assess the risk factors associated with knee joint degeneration after reshaping surgery for juvenile DLM. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Forty patients (45 knees) with a mean age of 12.0 years who underwent arthroscopic meniscal reshaping for DLM were enrolled at a mean of 39.6 months after surgery. For all patients, meniscal saucerization was performed first. Then, if the residual meniscus was unstable, stabilization was provided with suture fixation. At final follow-up, we obtained radiographs to assess degenerative changes to the knee joint using the classification by Tapper and Hoover. Residual meniscal width and meniscal extrusion (defined as a relative percentage of extrusion [RPE]) were measured with magnetic resonance imaging (MRI). Then, the correlation between radiographic evidence of degenerative changes (Tapper and Hoover grade), residual meniscal width, and RPE were assessed with Pearson and Spearman correlation analyses. Logistic regression analysis was used to examine whether preoperative characteristics correlated with degeneration and residual meniscal width. RESULTS: The mean residual meniscal width was 4.6 mm (range, 3.8-6.0 mm), and the mean ± SD RPE was 25.5% ± 21.8% at the final follow-up. There were 28 knees with Tapper and Hoover grade 0, 10 knees with grade 1, and 7 knees with grade 2. The residual meniscal width and RPE were significantly correlated with Tapper and Hoover grade (ρ = -0.489, P = .0007; ρ = 0.414, P = .005, respectively). The residual meniscal width was also significantly correlated with RPE ( r = -0.416, P = .004). The receiver operating characteristic curve showed that a 5.0-mm residual meniscal width was the cutoff value leading to evidence of degeneration. Multiple logistic regression analysis showed that an anterocentral shift on preoperative MRI was a risk factor for degeneration (odds ratio, 27.2; 95% CI, 1.1-360.5; P = .012) and residual meniscal width less than 5.0 mm (odds ratio, 20.9; 95% CI, 1.5-281; P = .022). CONCLUSION: Smaller meniscal width and greater severity of meniscal extrusion correlated with knee joint degeneration. An anterocentral shift on preoperative MRI was a risk factor for degenerative changes and smaller residual meniscal width.

One-stage revision ACL reconstruction after primary ACL double bundle reconstruction: is bone-patella tendon-bone autograft reliable?

PURPOSE: The purpose of this study is to assess the results of revision anterior cruciate ligament (ACL) reconstruction after the failure of primary ACL double bundle reconstruction (ACL-DBR). METHODS: Twenty-two knees in 22 patients (group R) that underwent ACL revision surgery using bone-patellar tendon-bone (BTB) autograft after the failure of primary ACL-DBR were included in this study. Intraoperative findings and postoperative knee laxity and clinical outcomes in group R were assessed. Forty-four knees in 44 patients that were age- and gender- matched with group R and underwent primary ACL reconstruction using BTB autograft were used as a control group (group P). RESULTS: The incidence of medial meniscus and cartilage injury in group R was significantly higher than those in group P (p < 0.05). At final follow-up, median Lysholm score was 90.5 (64-100) in group R and 94 (59-100) in group P, respectively. Fourteen patients (63.6%) in group R and 31 patients (70.5%) in group P were able to return to previously-played sports, respectively. There were no significant differences in KT-1000 outcomes (2.0 mm in group R and 1.4 mm in group P) or pivot shift test between the two groups. The rate of subsequent ACL injury was similar in both groups. CONCLUSIONS: Revision ACL reconstruction using BTB autograft after failed primary ACL-DBR provided almost compatible postoperative clinical outcomes and knee stability with primary ACL reconstruction using BTB autograft, while the incidence of medial meniscus and cartilage injury at revision surgery was higher. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

The origin and distribution of CD68, CD163, and αSMA+ cells in the early phase after meniscal resection in a parabiotic rat model.

We previously reported that circulating peripheral blood-borne cells (PBCs) contribute to early-phase meniscal reparative change. Because macrophages and myofibroblasts are important contributors of tissue regeneration, we examined their origin and distribution in the reparative meniscus. Reparative menisci were evaluated at 1, 2, and 4 weeks post-meniscectomy by immunohistochemistry to locate monocytes and macrophages (stained positive for CD68 and CD163), and myofibroblasts (stained positive for αSMA). Of the total number of cells, 13% were CD68+ at 1 week post-meniscectomy, which decreased to 1% by 4 weeks post-meniscectomy; of these, almost half of CD68+ cells (49.4%: 98.8% as PBCs) were green fluorescent protein (GFP)-positive post-meniscectomy (1, 2, and 4 weeks), indicating that the majority of CD68+ cells were derived from PBCs. Of the total cells, 6% were CD163+ at 1 week post-meniscectomy, which decreased to 1% by week 4. Of the CD163+ cells, the majority were GFP-positive (42.5%: 85.0% as PBCs) after 1 week; however, this decreased significantly over time, which indicates that the majority of CD163+ cells are derived from PBCs during the early phase of meniscal reparative change, but are derived from resident cells at later time points. Of the total cells, 38% were αSMA+ at 1 week post-meniscectomy, which decreased to 3% by 4 weeks. The proportion of GFP-positive αSMA+ cells was 2.8% after 1 week, with no significant change over time, which indicates that the majority of αSMA+ cells originated from resident cells. Here, we describe the origin and distribution of macrophages and myofibroblasts during meniscal reparative change.

Circulating nucleated peripheral blood cells contribute to early-phase meniscal healing.

The purpose of this study was to assess how peripheral blood cells (PBCs) contribute to meniscus repair, using a parabiotic rat model. Wild-type (WT) and green fluorescent protein (GFP) transgenic rats were conjoined at the torso. After 4 weeks, the anterior part of the medial meniscus of both groups of rats was removed. At 1, 2, 4, 8 and 12 weeks post-meniscectomy, repaired tissue was evaluated using stereomicroscopy, histology with toluidine blue staining, and immunofluorescence microscopy. Stereomicroscopic observations and confocal laser microscopy revealed that a high number of GFP-positive cells were present in the repaired meniscus of WT rats 1 week post-meniscectomy, and the number of GFP-positive cells decreased over time. Based on blood chimerism, the ratios of PBCs in the repaired meniscus were 20.5 ± 2.3% at 1 week, 8.3 ± 0.9% at 2 weeks, 4.4 ± 0.9% at 4 weeks, 2.1 ± 0.9% at 8 weeks, and 0.5 ± 0.4% at 12 weeks, post-meniscectomy. Histologically, fibrochondrocytes were observed in the repaired meniscus of WT rats after 4 weeks, some of which were GFP-positive. The chondrogenic marker, type II collagen, was merged within the PBCs in the repaired tissue. However, type-II-collagen-positive cell ratio and metachromasia in the repaired meniscus were not equivalent in normal meniscal tissue. This indicated that PBCs were present within the repaired meniscus at an early phase, replacing the excised meniscal cells, suggesting PBCs contributed to meniscal healing. The tissue repair contribution by these cells decreased at later phases. Copyright © 2014 John Wiley & Sons, Ltd.

A case of asymptomatic bilateral massive pulmonary embolism after arthroscopic multiple knee ligament reconstruction.

Venous thromboembolism, which includes deep venous thrombosis (DVT) and pulmonary embolism (PE), is a serious complication after operations involving the lower extremities, and it can be fatal. However, few reports have described the incidence of PE and its associated risk factors after arthroscopic knee surgery. We present a case of bilateral massive PE of the main pulmonary arteries and DVT detected on multi-detector row computed tomography after arthroscopic multiple knee ligament reconstruction. Our patient was asymptomatic despite having several risk factors for thromboembolic events (43 years of age, a long operation time, obesity, and diabetes mellitus) and receiving no pharmacologic thromboembolic prophylaxis. Although fatality due to PE is relatively uncommon, when a patient has several risk factors for PE, perioperative thromboprophylaxis should be considered. Level of evidence IV.