Changes in patellar height after anatomical ACL reconstruction with BTB autograft with a focus on patellar tendon removal volume.

BACKGROUND: Although anatomical anterior cruciate ligament reconstruction (ACLR) can provide satisfactory outcomes, little is known about how this procedure impacts patellar height. Since harvesting bone-patellar tendon-bone (BTB) autografts is a potential risk factor for decreased patellar height, we examined changes in patellar height after anatomical ACLR with BTB autograft with a focus on the size of the harvested graft. METHODS: Subjects were 84 patients (49 males, 35 females; mean age, 23 years) who underwent primary anatomical ACLR with central third BTB autograft. Preoperative to postoperative Caton-Deschamps index (CDI) ratio was calculated using lateral knee radiographs before and 6 months after surgery. The length and cross-sectional area (CSA) of the graft were measured intraoperatively, and the CSA of the contralateral patellar tendon was measured by ultrasound 6 months postoperatively. The difference in graft CSA relative to the contralateral tendon CSA, expressed as a percentage (gCSA:ctCSA percentage), was also calculated. RESULTS: Patellar height decreased slightly after surgery (preoperative CDI: 0.856 ± 0.113; postoperative CDI: 0.841 ± 0.113), with a mean difference between preoperative and postoperative CDIs of -0.015 (range: -0.293 to 0.101). Although the CDI of male subjects significantly decreased after surgery (preoperative: 0.852 ± 0.117; postoperative: 0.827 ± 0.115), no significant changes were noted in female subjects (preoperative: 0.862 ± 0.108; postoperative: 0.861 ± 0.108). Graft length and CSA did not significantly impact the CDI ratio (r = -0.138 and r = -0.038, respectively). Moreover, no significant relationship was observed between the gCSA:ctCSA percentage and CDI ratio (r = 0.118). CONCLUSIONS: Although patellar height slightly, but significantly, decreased at 6 months after anatomical ACLR with BTB autograft, it was not affected by the length and CSA of harvested grafts. The decrease in postoperative patellar height was observed only in male subjects, suggesting the potential importance of sex differences in soft tissue healing during the postoperative period.

Rectangular bone-patellar tendon bone grafts reduce early graft failure in chronic ACL-Deficient knees.

BACKGROUND: The aim of this study was to assess early graft failure after anterior cruciate ligament (ACL) reconstruction according to chronicity of ACL deficiency (ACLD) and clarify predisposing factors. METHODS: A total of 731 patients who underwent anatomic ACL reconstruction were divided into 3 groups based on chronicity of ACLD: <6 months (Group 1), 6 months to 2 years (Group 2), and >2 years (Group 3). Types of ACL grafts used included single-bundle hamstring tendon (HT), multiple-bundle HT, and rectangular bone-patellar tendon-bone (BTB) grafts. Preoperatively and immediately postoperatively, lateral radiographs in full extension were taken to examine anterior tibial subluxation (ATS). All ACL grafts were evaluated by MRI at 6 months to identify graft failure. The group with the highest failure rate was further examined to compare possible risk factors between the intact and failure subgroups, followed by multivariate logistic regression analysis to identify predisposing factors. RESULTS: Early graft failure on MRI without any episode of postoperative trauma was observed in 7 (1.4%), 2 (1.8%), and 11 (9.2%) patients in Groups 1, 2, and 3, respectively, with a significantly higher rate in Group 3 (P < 0.001). Of the 119 patients in Group 3, significant differences were observed between intact and failure subgroups with regard to surgical procedure (P = 0.03), chondral lesions (P < 0.01), and preoperative ATS (P < 0.01). Multivariate logistic regression analysis revealed that surgical procedures (odds ratio, 3.8; 95%CI, 1.16-12.59) and preoperative ATS (odd ratio, 2.4; 95%CI, 1.26-4.38) were predisposing factors of early graft failure. CONCLUSION: Patients with ACLD for >2 years experienced early graft failure with an incidence rate of 9.2%. Predisposing factors of early graft failure in these patients included the use of single-bundle HT grafts and preoperative ATS. The use of rectangular BTB grafts resulted in a lower graft failure rate. STUDY DESIGN: Case Series.

Posterior Ankle Impingement Caused by Hyaline-Like Cartilage Generation in Ballet Dancers-A Report of 2 Cases.

Posterior ankle impingement syndrome is mainly seen in ballet dancers and frequently associated with specific movements in ballet such as pointe and demi pointe in which the whole-body weight is applied to the maximally plantar flexed ankle. We performed arthroscopic debridement for 2 dedicated ballet dancers on the intervening soft tissue causing posterior ankle impingement syndrome (PAIS). In both cases, T2-weighted magnetic resonance imaging (MRI) revealed low-signal intensity of meniscus-like soft tissue without abnormal osseous findings, connecting from the posterior side of the talus to Kager's fat pad. To examine the intervening soft tissue in detail, we performed histological evaluation by hematoxylin and eosin staining, Safranin O fast green staining, and immunohistochemistry for type I collagen and type II collagen. Hematoxylin and eosin staining showed that there was cartilage-like tissue including chondrocyte-like cells in contact with fibrous tissue. The extracellular matrix in the cartilage zone was consistently stained by Safranin O staining and type II collagen without any staining with type I collagen. These findings suggested that the meniscus-like soft tissue appearing as low-signal intensity on MRI at the posterior side of talus included hyaline-like cartilage. To the extent of our knowledge, these were rare cases of hyaline-like cartilage generation causing PAIS in ballet dancers, which might be associated with ballet specific movements resulting in chondrogenesis.

Importance of functional performance and psychological readiness for return to preinjury level of sports 1 year after ACL reconstruction in competitive athletes.

PURPOSE: This study aimed to identify independent predictive factors for return to sports (RTS) after anterior cruciate ligament (ACL) reconstruction in competitive-level athletes and to determine optimal cut-off values for these factors at 6 months after surgery. METHODS: A total of 124 competitive athletes (50 males and 74 females; mean age, 17.0 years; preinjury Tegner activity scale > 7) who underwent primary ACL reconstruction were enrolled. Assessments at 6 months after surgery consisted of knee functional tests [quadriceps index, hamstrings index, and single-leg hop for distance (SLH)] and 2 self-report questionnaires [IKDC subjective score and ACL-Return to Sport after Injury scale (ACL-RSI)]. At 1 year after surgery, athletes were classified into the RTS group (n = 101) or non-RTS group (n = 23) based on self-reported sports activities. After screening possible predictive factors of RTS, multivariate logistic regression and receiver operating characteristic curve analyses were performed to identify independent factors. RESULTS: Multivariate logistic regression analysis identified SLH (odds ratio, 2.861 per 10 unit increase; P < 0.001) and ACL-RSI (odds ratio, 1.810 per 10 unit increase; P = 0.001) at 6 months as independent predictors of RTS at 1 year after surgery. Optimal cut-off values of SLH and ACL-RSI were 81.3% (sensitivity = 0.891; specificity = 0.609) and 55 points (sensitivity = 0.693; specificity = 0.826), respectively. CONCLUSION: In competitive athletes, SLH < 81% and ACL-RSI < 55 points at 6 months after surgery were associated with a greater risk of unsuccessful RTS at 1 year after surgery. SLH and ACL-RSI at 6 months could serve as screening tools to identify athletes who have difficulties with returning to sports after ACL reconstruction. LEVEL OF EVIDENCE: III.

Significant anterior enlargement of femoral tunnel aperture after hamstring ACL reconstruction, compared to bone-patellar tendon-bone graft.

PURPOSE: This study aimed to retrospectively compare the enlargement and migration of the femoral tunnel aperture after anatomic rectangular tunnel anterior cruciate ligament (ACL) reconstruction with a bone-patella tendon-bone (BTB) or hamstring tendon (HT) graft using three-dimensional (3-D) computer models. METHODS: Thirty-two patients who underwent ACL reconstruction and postoperative computed tomography (CT) at 3 weeks and 6 months were included in this study. Of these, 20 patients underwent ACL reconstruction with a BTB graft (BTBR group), and the remaining 12 with an HT graft (HTR group). The area of the femoral tunnel aperture was extracted and measured using a 3-D computer model generated from CT images. Changes in the area and migration direction of the femoral tunnel aperture during this period were compared between the two groups. RESULTS: In the HTR group, the area of the femoral tunnel aperture was significantly increased at 6 months compared to 3 weeks postoperatively (P < 0.05). The average area of the femoral tunnel aperture at 6 months postoperatively was larger by 16.0 ± 12.4% in the BTBR group and 41.9 ± 22.2% in the HTR group, relative to that measured at 3 weeks postoperatively (P < 0.05). The femoral tunnel aperture migrated in the anteroinferior direction in the HTR group, and only in the inferior direction in the BTBR group. CONCLUSIONS: The femoral tunnel aperture in the HTR group was significantly more enlarged and more anteriorly located at 6 months after ACL reconstruction, compared to the BTBR group. LEVEL OF EVIDENCE: IV.

Relationship between bone plug position and morphological changes of tunnel aperture in anatomic rectangular tunnel ACL reconstruction.

PURPOSE: In animal studies after ACL reconstruction (ACL-R) using the bone-patellar tendon-bone (BTB), the graft-healing pattern was found to depend on the relationship between bone plug and the tunnel wall. This difference of graft-healing pattern could influence the postoperative morphological changes of the tunnel. However, no study has assessed the relationship between bone plug position and the change of tunnel morphology. Therefore, the main purpose of this study was to investigate the relationship between the bone plug position within femoral or tibial tunnel and morphological changes of each tunnel aperture in ACL-R using computed tomography. METHODS: Subjects were 30 consecutive patients (six females and 24 males; mean age, 20.4 ± 5.4 years) who underwent primary ACL-R using BTB. The distance from the tunnel aperture to the tendon-bone junction (TBJ) at 2 weeks postoperatively, and tunnel aperture enlargement and tunnel wall migration from 2 weeks to 6 months postoperatively, were evaluated. RESULTS: The distance from the femoral tunnel aperture to the TBJ in most cases was less than 2 mm, whereas the TBJ was located within the tibial tunnel. Femoral tunnel aperture was significantly enlarged (17.0 ± 11.7%) distally, and the tibial tunnel aperture was significantly enlarged (19.6 ± 12.5%) posterolaterally. Only the position at distal portion of femoral bone plug was correlated with femoral tunnel aperture enlargement (r = 0.454, p = 0.0015). CONCLUSION: Both femoral and tibial tunnel aperture were significantly enlarged distally and posterolaterally 6 months postoperatively. Only correlation between the position at distal portion of femoral bone plug and femoral tunnel enlargement were found, suggesting the deep plug position in the tunnel is a risk factor for femoral tunnel enlargement, highlighting the importance of accurately locating the TBJ just at the femoral tunnel aperture. Another option is to deviate the harvest site in the patellar tendon to match the shape of the TBJ and the tunnel aperture. LEVEL OF EVIDENCE: 4 (case series).

Sex Differences in the Residual Patellar Tendon After Harvesting Its Central Third for Anterior Cruciate Ligament Reconstruction.

OBJECTIVES: Some studies have found that sex can affect the clinical results after anterior cruciate ligament reconstruction. We hypothesized that sex would significantly affect the healing of the postoperative patellar tendon. This study evaluated the patellar tendon after bone-patellar tendon-bone autograft harvest, specifically with regard to sex-dependent differences. METHODS: At 6 months postoperatively, an ultrasonographic evaluation was performed. We measured the residual donor site gap width between tendon tissues and the thickness of newly formed nontendinous tissue in the gap. In addition, the cross-sectional area of tendon tissue was measured. The ratios between the operated and contralateral sides were calculated, and the sexes were compared. A paired Student t test was performed, with P < .05 considered statistically significant. RESULTS: The population of 52 patients (32 male and 20 female) had a mean age ± SD of 23 ± 8 years. We observed no significant sex-dependent differences in the residual donor site gap and the thickness of newly formed nontendinous tissue when calculating ratios to the contralateral tendon. The mean cross-sectional area of tendon tissue was 101 ± 26 mm2 (male, 114 ± 26 mm2 ; female, 80 ± 16 mm2 ). When the ratios to the contralateral tendon were calculated, male patients had significantly higher cross-sectional area ratios than female patients (male, 124% ± 20%; female, 100% ± 19%, P = .024). CONCLUSIONS: We have reported a dramatic increase in the cross-sectional area of patellar tendon tissue during the first 6 months after anterior cruciate ligament reconstruction with a bone-patellar tendon-bone autograft, which was more prominent in male patients than in female patients. This difference might have contributed to the sex-dependent variation in clinical outcomes.

Second look arthroscopic evaluation of repaired radial/oblique tears of the midbody of the lateral meniscus in stable knees.

BACKGROUND: Radial/oblique tears of the midbody of the lateral meniscus significantly impair the ability of the meniscus to withstand the tibiofemoral load, requiring meniscal repair. However, healing status after meniscal repair has not been fully elucidated. This study aimed to evaluate arthroscopic findings after inside-out suture repair for isolated radial/oblique tears of the midbody of the lateral meniscus. METHODS: From 2011 to 2015, 18 consecutive patients with isolated radial/oblique tears of the midbody of the lateral meniscus underwent arthroscopic inside-out repair with the tie-grip suture technique. All knees were stable with no previous surgery. All patients were evaluated by second-look arthroscopy at six months postoperatively. Activities including jogging were not allowed until meniscal status was evaluated arthroscopically. To analyze factors associated with healing rates, age, time from injury to initial surgery, and tear zone were compared. RESULTS: Second-look arthroscopy revealed complete healing in four (22%) patients, partial healing in seven (39%), and failure to heal in seven (39%). Significant differences were observed for tear zone (p < 0.0001), but not for age and timing of repair. CONCLUSIONS: Arthroscopic evaluation revealed that inside-out repair with the tie-grip suture technique for isolated radial/oblique tears of the midbody of the lateral meniscus achieved complete or partial healing only in 61% of patients. Satisfactory results were observed particularly in patients with tears extending to the vascular zone, whereas those with tears in the avascular zone failed to achieve healing. Therefore, the operative indication of inside-out repair for radial/oblique tears of the midbody of the lateral meniscus might be limited to tears extending into the vascular zone. Given that 39% of cases were arthroscopically considered a failure even if patients complained of no symptoms in daily life, decisions should be made carefully to allow patients to return to sports activities.

Anterior knee symptoms after double-bundle ACL reconstruction with hamstring tendon autografts: an ultrasonographic and power Doppler investigation.

PURPOSE: Anterior knee pain related to the donor site is a frequent complication of anterior cruciate ligament reconstruction (ACLR) with bone-patellar tendon-bone autograft tissue. Even when hamstring tendon (HT) grafts are used instead, symptoms such as mild pain and discomfort can still occur. The purpose of this study was to elucidate the pathophysiology of anterior knee symptoms after ACLR with HT autografts. METHODS: Fifty-seven patients (22 men and 35 women; mean age, 24.7 years) who underwent anatomic double-bundle ACLR with HT autografts were examined 6 months post-operatively. The presence of anterior knee symptoms, anterior knee laxity, range of motion, and muscle strength were assessed. Changes in patellar tendon and infrapatellar fat pad (IFP) morphology and blood flow were also evaluated using ultrasound. Potential variables affecting the presence of anterior knee symptoms were subjected to univariate analysis and multivariate logistic regression analysis to identify independent risk factors. RESULTS: Six months post-operatively, the total incidence of anterior knee symptoms was 56.1 % (32/57). According to univariate analysis, age, quadriceps strength, and increased blood flow in the IFP were significantly associated with the presence of anterior knee symptoms. Multivariate logistic regression analysis revealed that increased blood flow in the IFP was an independent factor for the presence of anterior knee symptoms (odds ratio 5.0; 95 % confidence interval 1.3-19.9). There were no significant findings inside the patellar tendon. CONCLUSIONS: Increased blood flow in the IFP was identified as an independent factor for the presence of anterior knee symptoms 6 months after ACLR with HT autografts. The ultrasound evaluation can help to define precisely the origin of anterior knee symptoms after ACLR with HT autografts. LEVEL OF EVIDENCE: Case series with no comparison groups, Level IV.

Patellar mobility can be reproducibly measured using ultrasound.

The present study was performed to examine the reliability of ultrasound in evaluating patellar mobility in the superior-inferior direction. Twelve healthy men volunteered for the study. Patellar mobility in the superior-inferior direction during isometric knee extension contraction with the knee immobilized in a semi-flexed knee brace was measured using ultrasound. Both intra-observer and inter-observer reliability were assessed by intra-class correlation coefficients (ICCs). Bland-Altman analysis was used for assessing agreement between measurements. ICC values were excellent for both intra-observer and inter-observer reliability at 0.97 and 0.93, respectively. In 95 % of measurements, the same observer measured within -0.55 to 0.61 mm, while different observers measured within -0.82 to 0.85 mm. In conclusion, patellar mobility in the superior-inferior direction during an isometric knee extension exercise can be reproducibly measured using ultrasound. THE LEVEL OF EVIDENCE: VI (basic study of a novel evaluation method).

MRI analysis of single-, double-, and triple-bundle anterior cruciate ligament grafts.

PURPOSE: The purpose of the study was to evaluate the entire course of ACL grafts on coronal oblique MR images, focusing on differences in graft morphology and graft-to-tunnel healing among single-bundle (SB), double-bundle (DB), and triple-bundle (TB) reconstructions. METHODS: Eighty-three patients underwent anatomical ACL reconstruction using the semitendinosus tendon. SB reconstruction was performed on 20 patients, DB on 29 patients, and TB on 34 patients. The anteromedial-bundle (AMB) and posterolateral-bundle (PLB) images were extracted from coronal oblique images of grafts at 6 months to visualize their entire course. Signal intensity of grafts was measured independently in three regions: (1) intra-femoral tunnel region, (2) intra-articular region, and (3) intra-tibial tunnel region, followed by calculation of the signal-to-noise quotient (SNQ). To evaluate graft-to-tunnel healing, T2-weighted images were examined for the presence of a high signal-intensity lesion between the graft and bone tunnel around the tunnel aperture. RESULTS: AMB images showed that SB graft was thick throughout the entire course, while DB graft was thinner than SB graft. TB graft showed a fan shape approaching the tibial tunnels. The SNQ in the femoral tunnel of SB graft was significantly lower than in the DB and TB grafts. High signal-intensity lesions were frequently observed around the femoral tunnel aperture in PLB images of DB and TB grafts compared to SB grafts. CONCLUSION: Gross morphology of TB grafts resembled that of the natural ACL. However, the graft-to-tunnel healing around the femoral tunnel seemed to be insufficient in PLB images of DB and TB compared to SB grafts.

Patellofemoral chondral status after medial patellofemoral ligament reconstruction using second-look arthroscopy in patients with recurrent patellar dislocation.

BACKGROUND: Most patients with recurrent patellar dislocation show cartilage damage in the patellofemoral joint. Medial patellofemoral ligament reconstruction has become one of the most important surgical techniques for treating recurrent patellar dislocation. However, patellofemoral chondral status after this reconstruction has not been elucidated. The purpose of this study was to investigate the effects of medial patellofemoral ligament reconstruction on articular cartilage in the patellofemoral joint by comparing the arthroscopic chondral status at the time of reconstruction with that at second-look arthroscopy. METHODS: Participants in the present study comprised 31 patients (22 females, 9 males; 32 knees) who underwent second-look arthroscopy at a median of 12 months (range 6-40 months) after dual tunnel medial patellofemoral ligament reconstruction using a double-looped autologous semitendinosus tendon graft. Median age at the time of initial surgery was 20 years (range 13-43 years). The patellofemoral joint was divided into six portions, comprising the medial facet of the patella, central ridge, lateral facet of the patella, anterior medial femoral condyle, femoral groove, and anterior lateral femoral condyle. Chondral status in each portion according to the International Cartilage Repair Society classification was retrospectively evaluated at the time of initial surgery and second-look arthroscopy. RESULTS: Before medial patellofemoral ligament reconstruction, chondral lesions were observed in the patellofemoral joint in 31 knees (97%). At the central ridge of the patella, chondral damage was observed in 22 knees (69%) at initial surgery and damaged cartilages showed recovery in 6 knees. No significant difference in the alteration of chondral status was seen for the medial facet, lateral facet of the patella, anterior medial femoral condyle, femoral groove, and anterior lateral femoral condyle. CONCLUSIONS: According to short-term results, the patellofemoral chondral status after medial patellofemoral ligament reconstruction was not altered at second-look arthroscopy in most part of patellofemoral joint. At the central ridge of the patella, significant improvement of the International Cartilage Repair Society grading was observed.

All-inside suture meniscal repair using suture passer.

In recent years, to save the meniscus and prevent the progression of knee osteoarthritis, the indications for meniscus repair have been expanding instead of partial menisectomy. Accordingly, various repair techniques for meniscus tears have been developed. The conventional inside-out and outside-in meniscus repair techniques and all-inside repair technique with an implant/anchor can be classified as trans-capsular (TC) repair from the perspective of suture with penetrating capsule. Recently, new suture passers for all-inside meniscus repair have been developed. To distinguish from conventional all-inside repair with implant/anchors, all-inside repair with only suture using these suture passers was described as all-inside suture (AIS) repair. This AIS repair could achieve meniscus-to-meniscus suture across the tear without interposition of soft tissues including the capsule between suture and meniscus, leading direct gap closing of torn edges. In this respect, AIS repair is considered to be "anatomical meniscus repair". Actually, some reports showed biomechanical and clinical advantages of AIS repair. However, there is still limited evidence in clinical practice. Moreover, there are some disadvantages for AIS repair. Not only further studies but also development of new devices and surgical techniques for AIS should be required. This review describes the current status of AIS repair for each type of tear.

Association of Stability and Size of Unhealed Area With Failure After Internal Fixation for Osteochondritis Dissecans Lesions of the Knee: Radiological Evaluation Using Computed Tomography.

BACKGROUND: Open reduction and internal fixation (ORIF) has been widely performed because the osteochondral component of the osteochondritis dissecans (OCD) lesion is the most suitable for reconstructing the joint structure. PURPOSE: To evaluate radiological healing in terms of reconstructed bony structure after ORIF with bone graft by computed tomography (CT), to identify preoperative prognostic factors for failure, and to determine the cutoff value of radiological healing for risk of failure. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A retrospective cohort study of 42 patients (44 knees) who underwent internal fixation with bone graft for OCD lesions of the knee from 2004 to 2018 was conducted. All patients were evaluated 6 months postoperatively, and if not healed 6 months after surgery, they were evaluated by CT periodically thereafter. Radiological healing was judged according to the following 3 criteria: (1) reossification of the OCD lesion, (2) bony continuity between the OCD lesion and basal floor, and (3) reconstructed bony surface of the femoral condyle reconstructed to match the normal joint. Then, the percentage of the radiological healing area was calculated as the ratio of the healing length to the total lesion length. The nonhealing area was calculated by multiplying the sum of the total nonhealing length. Clinical failure was defined as any definitive reoperation for the same OCD lesion, such as fragment excision, or a cartilage restoration procedure. After 6 months, all eligible patients underwent arthroscopy to check for protrusion of the absorbable pin into the joint; the removal of an absorbable pin protruding into the joint was not considered a failure. RESULTS: Clinical failure was recorded for 4 cases (9.1%). The mean overall percentage of the radiological healing area of OCD 6 months after ORIF with bone graft was 79.5% ± 24.4%, and the mean overall nonhealing area at 6 months was 87.8 ± 107.9 mm2. The percentages of radiological healing area of stable (International Cartilage Regeneration & Joint Preservation Society OCD II) lesions and femoral condylar (lateral femoral condyle + medial femoral condyle) lesions were significantly lower than unstable lesions and femoral groove lesions, respectively (P = .01 and P = .03, respectively). On receiver operating characteristic curve analysis, the cutoff points for predicting a significantly increased risk of failure were 33.9% (sensitivity, 100%; specificity, 100%; area under the curve, 1) for the percentage of radiological healing area and 222.9 mm2 (sensitivity, 95%; specificity, 100%; area under the curve, 0.956) for the nonhealing area 6 months postoperatively. CONCLUSION: A stable lesion and a femoral condylar lesion were the predictors of poor radiological healing on CT images 6 months after ORIF with bone graft. The risk of failure was increased significantly in cases with only approximately one-third of the lesion healed or in cases with large nonhealing areas at 6 months postoperatively.

The intact posterior cruciate ligament not only controls posterior displacement but also maintains the flexion gap.

BACKGROUND: The PCL is a strong stabilizer of the knee and provides posterior stability to the tibia. However, sagittal alignment of the PCL with the knee at 90° flexion suggests the PCL might play a role not only in posterior stabilization but also in maintaining the flexion gap. QUESTIONS/PURPOSES: We determined whether the intact PCL helps maintain the flexion gap. METHODS: We examined axial radiographs and gravity sag views of 17 patients with chronic isolated unilateral PCL injury. The flexion gap was defined as the mean value of the medial and lateral distances between the femoral and tibial bones on the axial radiograph. Increase in the flexion gap and posterior laxity were determined by comparing the patients' injured and contralateral uninjured knees. RESULTS: The flexion gap of PCL injured knees (median, 7.5 mm; range, 5.3-11.5 mm; medial median, 6.2 mm; medial range, 3.7-8.3 mm; lateral median, 7.9 mm; lateral range, 5.3-11.5 mm) was larger than that seen in uninjured knees (median, 5.0 mm; range, 4.0-7.6 mm; medial median, 4.6 mm; medial range 3.4-7.1 mm; lateral median, 5.6; lateral range, 4.5-11.2 mm). The increment in the medial distance was similar to that in the lateral distance. Posterior laxity of injured knees was 9.1 (median); 5.4 to 15.2 (range) mm greater than that of uninjured knees. We found no correlation between posterior laxity and the flexion gap increment. CONCLUSIONS: Our data suggest the intact PCL controls posterior displacement and maintains the flexion gap.

Change of signal intensity in the displaced medial meniscus after its reduction on MRI.

PURPOSE: To compare magnetic resonance (MR) signal intensity in the medial meniscus at the time of displacement and after its reduction in patients with a displaced bucket-handle tear of the meniscus associated with anterior cruciate ligament (ACL) injury. METHODS: Nine chronic ACL-deficient patients (3 male, 6 female, mean age 29 years) with locking due to a displaced fragment of the medial meniscus following a bucket-handle tear were involved in this study. In all patients, the following two-stage surgeries were planned as follows: first operation, arthroscopic reduction of the meniscus; second operation, meniscal repair and ACL reconstruction after immobilization for 1-2 weeks. Magnetic resonance imaging (MRI) evaluation using coronal T2*-weighted images was performed when the knee was locked and after the meniscus was reduced. Signal intensity before and after meniscal reduction was compared in the same patients. RESULTS: In 8 of the 9 patients, the displaced fragment exhibited high signal intensity in 1 patient and mildly high in 7 patients. After its reduction, the signal intensity changed to low in all 8 patients. CONCLUSIONS: A high-intensity signal in the displaced fragment of the medial meniscus may change to low after its reduction to its original position. Therefore, at the time of decision-making regarding meniscus repair for a displaced meniscus in a locked knee, surgeons should give priority to arthroscopic findings rather than to signal intensity on MRI. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Single-Leg Loading Test to Predict Time to Jog and Return to Sports after Acute Lateral Ankle Sprain in Competitive Athletes.

In a previous study, the utility of a single-leg loading (SLL) test after acute lateral ankle sprain (LAS) was reported. However, whether the severity level assessed by the SLL test is associated with the time to jog and return to sports (RTS) remains unclear. Therefore, this study aimed to examine whether the time to jog and RTS differ depending on the severity level. A total of 240 athletes after sustaining acute LAS were included in this study. The SLL test was performed at the first visit, and the patients were classified into four levels (Levels 1-4). The Steel-Dwass multiple comparison method and multiple regression analysis was performed to verify whether the SLL test can predict the time to jog and RTS. On examining the relationship between the severity levels assessed by the SLL test and time to jog and RTS, significant differences were found among almost all the severity levels. Moreover, the multiple regression analysis revealed that only the SLL test showed a significant correlation with both the time to jog and RTS. This study suggested that the time to jog and RTS can be predicted by conducting the SLL test for acute LAS and dividing the severity into four levels.

Clinical outcomes after repair of an isolated radial tear in the middle segment of the lateral meniscus - All-inside suture repair vs trans-capsular suture repair.

Background/objective: For radial tears, all-inside suture (AIS) repair was clearly biomechanically superior, compared to conventional trans-capsular suture (TCS) repairs. However, clinical comparative studies of these two repairs techniques have not to be performed. Therefore, the aim of this study was to compare the clinical outcomes after AIS repair and TCS repairs for isolated radial tear at middle segment of lateral meniscus (RTMLM) in stable knees of young athletes. Methods: Twenty-six athletes (mean age, 19.1 years) underwent AIS repair with the double horizontal suture technique, using SutureLasso™ (Arthrex, Naples, FL) for isolated RTMLM (AIS group), and 20 athletes (mean age, 19.0 years) underwent inside-out repair, one of TCS repairs, with tie-grip suture technique (TCS group). All athletes were assessed for preoperative and two-year postoperative Knee injury and Osteoarthritis Outcome Score (KOOS). At six-month after repair, the lateral meniscal extrusion on mid-coronal plane on MRI and healing status on second-look arthroscopy were also evaluated in all patients. Results: In both groups, KOOS improved to either good or excellent postoperatively, while complete healing was found in only 23 and 25% at second-look arthroscopy. We identified no group-dependent differences in KOOS or healing status on arthroscopy. However, a close examination of failure rates revealed significant lower rates in AIS group relative to that of TCS group (p = 0.048). Moreover, the change from preoperative to postoperative lateral meniscal extrusion in AIS group was significantly smaller than that in TCS group (p = 0.038). Conclusions: AIS and TCS repairs for RTMLM were comparable in providing satisfactory clinical results with low rates of complete healing on arthroscopy. However, AIS repair could have lower failure rate of healing on arthroscopy and minimize postoperative lateral meniscal extrusion more effectively than TCS repair on MRI.

Five-Year Outcomes After Implantation of a Scaffold-Free Tissue-Engineered Construct Generated From Autologous Synovial Mesenchymal Stromal Cells for Repair of Knee Chondral Lesions.

Background: In an earlier study, a scaffold-free tissue-engineered construct (TEC) derived from autologous synovial membrane mesenchymal stromal cells (MSCs) was developed and demonstrated to be safe and effective for cartilage repair at 2 years postoperatively. Purpose: To investigate clinical outcomes and magnetic resonance imaging (MRI) findings at 5 years after implantation. Study Design: Case series; Level of evidence, 4. Methods: This was an observational first-in-human study limited to 5 patients (age, 28-46 years) with symptomatic knee chondral lesions (size, 1.5-3.0 cm2) on the medial femoral condyle, lateral femoral condyle, or femoral groove. Synovial MSCs were isolated from arthroscopic biopsy specimens and cultured to develop a TEC that matched the lesion size. The TECs were then implanted into chondral defects without fixation and assessed at up to 5 years postoperatively. The patients were clinically evaluated using the visual analog scale for pain, Lysholm score, Tegner score, and Knee injury and Osteoarthritis Outcome Score. An MRI scan evaluation was also performed for morphologic and compositional quality of the repair tissue at both 2 and 5 years of follow-up. Results: All clinical scores were significantly improved from the preoperative evaluation to the 2- and 5-year follow-ups and the results were stable over time. The MRI scan evaluation showed cartilage defects filled with newly generated tissues with good tissue integration to adjacent host cartilage over time. The cartilage thickness and surface smoothness of the repair cartilage were maintained up to 5 years postoperatively. The MOCART (magnetic resonance observation of cartilage repair tissue) 2.0 Knee Scores remained high at 5 years, although the total points decreased slightly. Conclusion: The results highlight the efficacy and feasibility of autologous scaffold-free TEC derived from synovial MSCs for regenerative cartilage repair via a sutureless and simple implantation procedure, showing good clinical outcomes and MRI findings with stable results at midterm follow-up. Further follow-up will be needed to assess the long-term quality of the repair tissue.