Background: Derotational distal femoral osteotomy (DDFO) has been used to treat patients with recurrent patellar dislocation (RPD) with increased femoral anteversion. However, no study has reported second-look arthroscopic findings in the patellofemoral joint after DDFO. Purpose: To report clinical and second-look arthroscopic outcomes for DDFO with combined medial patellofemoral ligament reconstruction (MPFL-R) in treating RPD with increased femoral anteversion. Study Design: Case series; Level of evidence, 4. Methods: From 2015 to 2019, 131 consecutive patients (144 knees) with RPD were treated with combined MPFL-R and DDFO. Patients with a femoral anteversion angle >30° and a minimum 2-year clinical follow-up period were included in the study. Three-dimensional computed tomography was performed to evaluate rotational deformities of the lower leg. Radiographic parameters presenting bony abnormalities associated with RPD were measured. Second-look arthroscopic evaluations were available for 86 knees to assess patellar tracking and chondral lesion changes. Moreover, clinical and radiologic outcomes were assessed pre- and postoperatively at a minimum 2 years. Results: A total of 102 knees in 92 patients were included in the present study with a mean clinical follow-up of 4.1 years (range, 2.0-5.6 years). Mean ± SD femoral anteversion changed significantly from 34.7°± 7.5° preoperatively to 11.3°± 0.2° postoperatively ( P < .001), and mean tibial tubercle–trochlear groove distance decreased significantly from 19.6 ± 3.5 mm preoperatively to 17.4 ± 3.2 mm postoperatively ( P < .001). In the majority of knees, at the time of second-look arthroscopic assessment, chondral lesion status remained unchanged at the lateral patellar facet (96%) and trochlear groove (95%); in contrast, chondral damage at the medial patellar facet was aggravated in 9 cases (10%). All functional scores (Tegner, Lysholm, visual analog scale, and Kujala scores) improved significantly at final follow-up. None of the patients experienced redislocation or subluxation after surgery. Conclusion: Chondral lesions in the patellofemoral joint remained unchanged in the majority of cases in second-look arthroscopy after combined MPFL-R and DDFO. Moreover, high-grade trochlear dysplasia and arthroscopic residual patellar maltracking might be associated with cartilaginous deterioration at the medial patellar facet after surgery.

Objective:To explore the effects of risk grading nursing on the prevention of postoperative deep vein thrombosis (DVT) and quality of life in patients undergoing knee arthroscopic surgery.Methods:A total of 1 140 patients undergoing knee arthroscopic surgery in Beijing Jishuitan Hospital were selected. The 529 cases with routine nursing from January to December 2018 were selected as the control group, while another 611 cases with risk grading nursing from January to December 2019 were selected as the observation group. The incidence of DVT, limbs swelling, quality of life and nursing satisfaction were compared between the two groups.Results:The incidence of DVT and the positive rates of Homan sign and Neuhof sign were 2.78% (17/611), 3.93% (24/611), 4.91% (30/611) in the observation group, and 5.10% (27/529), 10.02% (53/529), 11.72% (62/529) in the control group, the differences were statistically significant ( χ2=4.12, 16.70, 17.72, all P<0.05). The peripheral diameter and body surface temperature at 5 cm above the ankle, 10 cm below the patella and 15 cm above the patella were (21.30 ± 1.72) cm, (34.89 ± 2.75) cm, (46.69 ± 4.58) cm, (33.14 ± 1.40) ℃, (34.45 ± 1.52) ℃, (35.22 ± 1.36) ℃ in the observation group, and (22.88 ± 1.43) cm, (35.91 ± 1.81) cm, (49.18 ± 4.23) cm, (34.39 ± 1.22) ℃ (35.88 ± 1.49) ℃, (35.97 ± 1.31) ℃ in the control group, the differences were statistically significant ( t values were -16.74--7.25, all P<0.05). The scores of general health, physiological function, physiological function, mental health, social function, emotional function, body pain and body vitality were (75.84 ± 5.33), (79.78 ± 5.71), (76.71 ± 4.14), (84.91 ± 4.15), (75.53 ± 4.19), (78.80 ± 6.76), (74.85 ± 3.49), (78.61 ± 3.52) points in the observation group, and (71.39 ± 4.28), (75.44 ± 6.26), (73.05 ± 4.09), (80.15 ± 6.87), (71.66 ± 4.18), (74.89 ± 6.23), (71.14 ± 5.20), (74.66 ± 5.14) points in the control group, the differences were statistically significant ( t values were 10.10-15.57, all P<0.05). The satisfaction scores of nursing communication, safety, nursing technology, nursing, guidance and physical environment were (4.54 ± 0.42), (4.75 ± 0.46), (4.54 ± 0.52), (4.60 ± 0.48), (4.60 ± 0.53), (4.30 ± 0.64) points in the observation group, and (3.93 ± 0.34), (3.98 ± 0.37), (3.96 ± 0.41), (3.93 ± 0.38), (3.85 ± 0.36) (3.74 ± 0.38) points in the control group, the differences were statistically significant ( t values were 17.62-30.82, all P<0.05). Conclusions:Risk grading nursing is beneficial to alleviate postoperative limb swelling in patients after knee arthroscopic surgery, reduce incidence of DVT, improve quality of life and nursing satisfaction.

Steep (>13°) posterior tibial slope (PTS), excessive (>10 mm) anterior tibial subluxation (ATS) in extension and meniscal posterior horn tears (MPHTs) have been identified to be associated with primary anterior cruciate ligament reconstruction (ACLR) failure [1]. Recent studies have reported that steep PTS is directly correlated with excessive ATS in extension and concomitant MPHTs, especially for those with chronic (>6 months) ACL deficiency. There is growing biomechanical evidence that slope-reducing tibial osteotomy decreases ATS in extension and protects ACL graft.

Objective:To investigate the relationship between anterior tibial translation (ATT) and bony morphology around the knee after anterior cruciate ligament (ACL) injury.Methods:A total of 67 patients diagnosed with acute ACL injury without any meniscal lesions were enrolled in this study between September 2019 and August 2020. Preoperative magnetic resonance imaging (MRI) scans were used to measure the ATT of the lateral compartment, and bony morphology was assessed by measuring lateral femoral condyle (LFC) length, LFC height, lateral tibial plateau (LTP) length, LTP slope and by calculating the following ratios: LFC ratio (LFC length/LFC height), knee extension ratio (LFC length/LTP length), and knee flexion ratio (LFC height/LTP length). The status of the anterolateral ligament (ALL) was assessed by preoperative MRI scans and classified as completely injured (44 patients), partially injured (19 patients), or intact (4 patients). The ATT was compared between patients with completely injured ALL and those with partially injured or intact ALL. Pearson correlation analysis between the ATT and each bony variable was performed in ALL-completely-injured patients and ALL-partially-injured or intact patients.Results:Of the 67 patients, 33 were male and 34 were female, with a mean of age 31.7±9.7 years (range 15-47 years). The average of time interval between ACL injury and MRI examination was 26.0±22.0 days (95% CI: 20.7, 31.4 d). The ATT of the lateral compartment was 5.6±4.0 mm (range, -4.9-16.2 mm), the average of LFC length was 37.3±2.5 mm (range, 30.5-43.2 mm), the average of LFC height was 37.4±3.6 mm (range, 30.6-46.3 mm), the average of LTP length was 46.9±4.1 mm (range, 39.0-56.8 mm), the average of LTP slope was 6.3°±3.1° (range, -3.7°-11.6°), LFC ratio was 100.4%±8.1% (range, 84.1%-119.0%), knee extension ratio was 80.0%±5.8% (range, 66.1%-96.3%), and knee flexion ratio was 80.0%±6.0% (range, 66.4%-93.8%). The ATT was greater in patients with completely injured ALL than in patients with partially injured or intact ALL (6.4±4.3 mm vs. 3.9±2.8 mm, t=2.52, P=0.014). The ATT was negatively correlated with LFC height ( r=-0.43, P<0.001) and LTP length ( r=-0.35, P=0.004) and was positively correlated with LFC ratio ( r=0.48, P<0.001), knee extension ratio ( r=0.36, P=0.003), and LTP slope ( r=0.29, P=0.018). All these correlations were still statistically significant in patients with complete ALL injury ( P<0.05), but were no significant in patients with partial ALL injury or intact ALL ( P>0.05). Conclusion:Bony morphology of the distal femur and proximal tibia was associated with ATT after ACL injury. Such an association was more dramatic in patients with a complete ALL injury.

The popliteus tendon (PT) is reported to be injured in 68% of patients with posterolateral rotational instability (PLRI) [1]. As a part of posterolateral corner (PLC) injury, PT injury usually combines with lateral collateral ligament (LCL), medial collateral ligament (MCL), and cruciate ligament injuries [1, 2]. According to a biomechanical study [3], PT acts as the primary stabilizer of the external rotation of the knee and a secondary stabilizer of internal rotation, varus angulation, and anterior translation.

BACKGROUND:Increased posterior tibial slope (PTS) has been reported to be associated with irreducible anterior tibial subluxation in extension after anatomic anterior cruciate ligament (ACL) reconstruction (ACLR), which raises concerns about the greater risk of graft roof impingement (GRI) although the tibial tunnel is positioned anatomically.HYPOTHESIS:Increased PTS would be associated with greater risk of GRI after anatomic ACLR.STUDY DESIGN:Case-control study; Level of evidence, 3.METHODS:Between January 2016 and December 2017, a total of 418 consecutive patients were diagnosed as having noncontact ACL injuries and underwent primary anatomic ACLR. Among them, 26 patients had ≥1 of the following features during the second-look arthroscopy: fractured/guillotined bundles at the tibial insertion or cyclops lesion. These patients were confirmed to have GRI and were allocated to the study group. They were also matched 1:2 to 52 control participants without GRI. PTS was measured on true lateral whole-leg radiographs. Intra-articular ACL graft signal intensity was evaluated on postoperative magnetic resonance imaging scans (mean, 32.8 months; range, 26-38 months) and divided into 3 grades (I, good; II, moderate; III, poor) based on degree of GRI. Moreover, anterior subluxation of the lateral compartment (ASLC) and medial compartment (ASMC) in extension relative to the femoral condyles were measured on postoperative magnetic resonance imaging scans and compared between the groups. In addition, predictors of GRI were evaluated using multivariate logistic regression analysis and included body mass index, PTS, pivot-shift test, KT-1000 side-to-side difference, and concomitant meniscal tears.RESULTS:PTS in the study group was significantly higher than that in control group (mean ± SD, 13.8°± 1.5° vs 9.5°± 1.8°; P < .05). In the study group (n = 26), patients with grade III (poor) graft signal intensity (n = 9) showed significantly higher PTS than those with grade II (moderate; n = 17) (16.4°± 1.7° vs 12.4°± 1.3°; P < .05). Moreover, the mean postoperative ASLC and ASMC in extension were significantly larger in the study group than the control group (ASLC, 4.1 ± 1.3 vs 0.8 ± 0.4 mm; ASMC, 4.3 ± 1.5 vs 0.9 ± 0.3 mm; P < .05). Furthermore, the abnormal degree of PTS (≥12°) was determined to be an independent risk factor associated with GRI after anatomic ACLR (odds ratio, 9.0 [95% CI, 3.7-30.2]; P < .001), whereas body mass index, grade of pivot-shift test, KT-1000 side-to-side difference, and concomitant meniscal tears were not.CONCLUSION:Increased PTS (≥12°) was associated with greater risk of GRI after anatomic ACLR. This may provide additional information for counseling patients with greater risk of GRI.

BACKGROUND:Controversy exists regarding the surgical treatment of recurrent patellar dislocation (RPD) with an increased femoral anteversion angle (FAA). Medial patellofemoral ligament reconstruction (MPFL-R) either alone or combined with derotational distal femoral osteotomy (DDFO) results in favorable clinical outcomes.PURPOSE:To compare the clinical outcomes of MPFL-R versus MPFL-R with DDFO in treating RPD with increased FAA (>30°).STUDY DESIGN:Cohort study; Level of evidence, 3.METHODS:Between January 2014 and December 2017, 126 patients (135 knees) with RPD and increased FAA (>30°) were surgically treated using MPFL-R with or without DDFO and eligible for this retrospective study. These patients were allocated into 2 groups based on whether an additional DDFO was performed: the DDFO group (MPFL-R + DDFO with or without tibial tubercle transfer; n = 66) and the control group (MPFL-R with or without tibial tubercle transfer; n = 69). Pre- and postoperative patellar stability was measured using stress radiography. Patellar maltracking (J-sign) and patient-reported outcomes (Kujala, International Knee Documentation Committee, Lysholm, and Tegner scores) were evaluated and compared between the 2 groups. Subgroup analysis was performed by stratifying the results in terms of the severity of preoperative patellar maltracking (low-grade vs high-grade J-sign).RESULTS:A total of 135 knees (126 patients) with a mean follow-up time of 3.7 ± 1.2 years were evaluated in the present study. The rates of postoperative MPFL residual graft laxity and residual J-sign were significantly lower in the DDFO group than in the control group (6% vs 19%, P = .028; 33% vs 54%, P = .018). The DDFO group had significantly higher Kujala (82.3 vs 76.7; P = .001) and Lysholm (83.7 vs 77.7; P = .034) scores than the control group had postoperatively. For patients with a preoperative high-grade J-sign, further subgroup analysis demonstrated that the DDFO group had a significantly lower rate of MPFL residual graft laxity than the control group had (18% vs 57%; P = .029).CONCLUSION:In this retrospective study, treatment of RPD with increased femoral anteversion using MPFL-R with DDFO yielded more favorable subjective and objective outcomes than did MPFL-R without DDFO, and this circumstance was more remarkable when the patients had a preoperative high-grade J-sign.

To compare the objective and subjective clinical outcome of minimally invasive popliteal tendon (PT) recess procedure versus arthroscopic PT reconstruction, combined with posterior cruciate ligament reconstruction in patients with Type A posterolateral rotational instability (PLRI). The hypothesis was that the two techniques had comparable clinical outcomes. Between 2012 and 2017, patients who were eligible for inclusion in this study if they (1) had Type A PLRI according to Fanelli’s classification with posterior tibial translation > 12 mm on stress radiography and side-to-side difference of dial test external rotation > 10°, (2) PT peel-off lesion or laxity with structural integrity (3) were followed for a minimum of 2 years with examination under anesthesia (EUA) and stress radiograph results. Evaluation included subjective scoring, knee stability examinations and second-look arthroscopic lateral gutter drive-through (LGDT) test. Patients who underwent PT recess procedure were designated as Group A, while patients who underwent arthroscopic PT reconstruction were labelled as Group B. The differences between the two groups were analyzed. A total of 61 eligible patients with a minimum follow-up time of 2 years were evaluated in the present study. At the final follow-up, there were no significant inter-group differences in Lysholm scores (Group A: 69.0 ± 16.5, Group B: 75.8 ± 14.6, ns), Tegner scores [Group A: 2 (1–4), Group B: 3 (1–5), ns], or IKDC subjective scores (Group A: 70.5 ± 13.5, Group B: 71.1 ± 9.1, ns). No significant difference in side-to-side difference on posterior stress radiography (Group A: 4.3 ± 3.8 mm, Group B: 4.7 ± 4.6 mm, P = 0.701), dial test result (Group A: 0.9 ± 4.4°, Group B: 1.6 ± 4.9°, ns) or LGDT test positive rate (Group A: 2/34, 5.9%, Group B: 2/27, 7.7%, ns) was observed. Both minimally invasive PT recess procedure and arthroscopic PT reconstruction significantly improved the knee stability and subjective outcome comparing with preoperative value. In a comparison with arthroscopic PT reconstruction, the recess procedure demonstrated comparable subjective and objective clinical outcome. When both PT reconstruction and PT recess procedure are indicated, the minimally invasive and graft-free recess procedure can be a viable option. III.

Background: Clinical outcomes of surgical repairs for tears of the lateral meniscus posterior root (LMPR) in patients undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) have not been comprehensively investigated. Purpose: To systematically review the clinical, radiographic, and arthroscopic results of surgical repairs for tears of the LMPR in patients undergoing ACLR. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic electronic search of the PubMed and Embase databases was performed to identify studies reporting clinical, radiographic, or arthroscopic results of surgical repairs for tears of the LMPR in patients undergoing ACLR. Each included study was abstracted regarding study characteristics, patient characteristics, surgical technique, and outcome measures. The methodological quality of the included studies was analyzed according to the Methodological Index for Non-Randomized Studies (MINORS) criteria. Results: Nine studies were included in this systematic review, representing a total of 215 knees in 215 patients. Overall, 123 side-to-side repairs and 89 pullout repairs were performed for tears of the LMPR during ACLR. After a mean follow-up of 33.9 months, significant improvements ( P < .05) were found in the mean Lysholm score (from 58.3 to 91.4) as well as the mean International Knee Documentation Committee subjective score (from 61.1 to 87.2). Weightbearing anteroposterior radiographs of 41 patients showed no significant narrowing of lateral joint space width. On magnetic resonance imaging scans, 31 patients demonstrated no significant progression of chondral lesions, and no significant decreases in meniscal extrusion on coronal planes were reported in another 76 patients. The complete/partial healing was 93.6% on second-look arthroscopy after side-to-side repairs for radial tears of the LMPR. The MINORS value showed a high risk of bias for all 9 studies. Conclusion: Patients with tears of the LMPR associated with ACL injuries achieved favorable functional scores after ACLR and LMPR repairs, and the side-to-side repair for radial tears of the LMPR succeeded in a high meniscal healing rate of >90%. However, the authors of this review were unable to definitively conclude whether LMPR repairs fully restore the hoop stress of the lateral meniscus.

The purpose of this study was to analyse the risk factors associated with residual graft laxity after medial patellofemoral ligament reconstruction (MPFL-R) in patients with recurrent patellar dislocation (RPD). A total of 312 consecutive patients (354 knees) with clinically diagnosed RPD who underwent MPFL-R from 2011 to 2015 were retrospectively analysed. Postoperative MPFL graft stability was assessed with patellofemoral stress radiography, and if the patellar central ridge surpassed the apex of the lateral femoral trochlea, the reconstructed MPFL was defined as having residual graft laxity. Finally, 15 patients who exhibited MPFL residual graft laxity (study group) were matched in a 1:2 fashion to 30 control participants (control group), who showed a normal postoperative patellar stability on stress radiography. Preoperative three-dimensional computed tomography (3D-CT) was used to identify patients with a high-grade J-sign. Femoral tunnel position was assessed using 3D-CT to identify cases with femoral tunnel malposition. Potential predictors of MPFL residual graft laxity, including age, sex, a preoperative high-grade J-sign, femoral tunnel malposition, and several radiological parameters, were assessed by logistic regression analysis. A preoperative high-grade J-sign was identified in 66.7% of the study group, which was significantly higher than that the 13.3% in the control group (P = 0.001). In addition, the presence of a preoperative high-grade J-sign (odds ratio, 11.9 [95% CI, 1.7–82.8]; P = 0.012) and femoral tunnel malposition (odds ratio, 8.2 [95% CI, 1.2–58.0]; P = 0.036) were determined to be independent risk factors associated with residual graft laxity after MPFL-R. The presence of a preoperative high-grade J-sign and femoral tunnel malposition are associated with residual graft laxity after MPFL-R in patients with RPD. These results may provide additional information for counselling patients on residual graft laxity after MPFL-R. Level III.

Background: The lateral meniscus posterior root (LMPR) lesion further decreases dynamic knee stability after anterior cruciate ligament (ACL) injury owing to the loss of the “wedge effect” maintained by the posterior horn of the lateral meniscus. However, the effect of LMPR lesions on the static tibiofemoral relationship in extension after ACL injuries is not determined. Purpose: To (1) determine the effect of LMPR lesions on anterior tibial subluxation of the lateral compartment (ATSLC) in extension in patients with ACL injuries and to (2) identify the LMPR-related factors associated with excessive ATSLC in extension. Study Design: Cohort study; Level of evidence, 3. Methods: Between January 2015 and December 2017, 405 consecutive patients with diagnosed ACL injuries who underwent primary ACL reconstructions were retrospectively reviewed. Among them, 45 patients with combined ACL injuries and LMPR lesions (ACL+LMPR group) and 51 patients with isolated ACL injuries (ACL group) were identified. Values of ATSLC in extension were measured on preoperative supine magnetic resonance imaging and classified into high grade (≥6 mm) and low grade (<6 mm). The mean ATSLC in extension and the proportion of patients with high-grade ATSLC in extension were compared between the groups by univariate analysis. In the ACL+LMPR group, predictors of high-grade ATSLC in extension—including age, sex, body mass index, affected side, cause of injury, period from injury (<12 or ≥12 weeks), LMPR lesion pattern (radial tear or root avulsion), and meniscofemoral ligament integrity (intact or impaired)—were assessed by univariate analysis and multivariate logistic regression analysis. Results: The mean ATSLC in extension in the ACL+LMPR group was significantly greater than that in the ACL group (5.6 mm vs 3.1 mm; P = .001). The proportion of patients with high-grade ATSLC in extension in the ACL+LMPR group was also significantly larger than that in the ACL group (44.4% vs 15.7%; P = .002). In addition, the root avulsion (instead of radial tear) (odds ratio, 28.750; 95% CI, 2.344-352.549; P = .009) and the period from injury ≥12 weeks (odds ratio, 17.095; 95% CI, 1.207-242.101; P = .036) were determined to be the 2 independent predictors of high-grade ATSLC in extension. However, age, sex, body mass index, affected side, cause of injury, and meniscofemoral ligament integrity were not. Conclusion: After ACL injuries, concomitant LMPR lesion further increased ATSLC in extension. Chronic LMPR avulsion was associated with high-grade ATSLC in extension.

Background: Steep posterior tibial slope (PTS) and excessive anterior tibial translation (ATT) have been identified as important anatomic risk factors for anterior cruciate ligament (ACL) injury, which have raised concerns about clinical outcomes after primary ACL reconstruction (ACLR). Purpose: To investigate anatomic risk factors of primary ACLR failure and to determine the cutoff values of PTS and ATT for predicting primary ACLR failure. Study Design: Case-control study; Level of evidence, 3. Methods: Between November 2015 and May 2017, a total of 215 consecutive patients with clinically diagnosed noncontact ACL injuries who underwent primary anatomic ACLR were retrospectively analyzed. Among them, 25 patients who showed complete discontinuity of ACL fibers on final follow-up magnetic resonance imaging scans were allocated into the failure group (study group). They were matched 1:2 to 50 control participants who showed clear and continuous ACL fibers on magnetic resonance imaging scans (control group). PTS and ATT were measured on preoperative weightbearing whole leg lateral radiographs and compared between the groups. The cutoff values of PTS and ATT for predicting primary ACLR failure were determined by the receiver operating characteristic curve. Moreover, predictors of primary ACLR failure were assessed by multivariate logistic regression analysis, including sex, age, body mass index, concomitant meniscal tears, degree of pivot-shift test, and KT-1000 arthrometer side-to-side difference, PTS, and ATT. Results: PTS and ATT values in the study group were significantly higher than those in the control group (mean ± SD: PTS, 17.2°± 2.2° vs 14.4°± 2.8°; ATT, 8.3 ± 3.4 mm vs 4.1 ± 3.1 mm; P < .001). The cutoff values of PTS and ATT for predicting primary ACLR failure were 17° (sensitivity, 66.7%; specificity, 90.9%) and 6 mm (sensitivity, 87.5%; specificity, 79.5%), respectively. Additionally, PTS ≥17° (odds ratio, 15.6; 95% CI, 2.7-91.5; P = .002) and ATT ≥6 mm (odds ratio, 9.9; 95% CI, 1.9-51.4; P = .006) were determined to be risk factors of primary ACLR failure, whereas sex, age, body mass index, concomitant meniscal tears, degree of the pivot-shift test, and KT-1000 arthrometer side-to-side difference were not. Conclusion: In this study, PTS ≥17° and ATT ≥6 mm, as measured on weightbearing whole leg radiographs, were identified to be predictive risk factors of primary ACLR failure. This study adds to the existing knowledge about potential surgical indications of simultaneous slope-reducing high tibial osteotomy to mitigate the primary ACLR failure rate.

Background: It has been speculated that the patellar J sign may have a negative effect on the clinical outcomes of patients with recurrent patellar dislocation (RPD). Purpose: To (1) evaluate clinical outcomes, postoperative patellar stability, and patellar maltracking correction in patients with RPD treated with derotational distal femoral osteotomy (DDFO) and combined procedures and (2) investigate the influence of J sign severity on the clinical outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: Between January 2015 and December 2016, a total of 78 patients (81 knees) with RPD, a positive J sign, and an excessive femoral anteversion angle (FAA; ≥30°) were surgically treated with DDFO and combined procedures. J sign severity was graded according to a previously described classification system (grades 1-3). Routine radiography and computed tomography were performed on every patient to evaluate the patellar height, trochlear dysplasia, genu valgum, tibial tuberosity–trochlear groove distance, patellar lateral tilt angle, and patella–trochlear groove distance. The patellar lateral shift distance during stress radiography was measured preoperatively and postoperatively to quantify medial patellofemoral ligament (MPFL) graft laxity under anesthesia, and “MPFL residual graft laxity” was defined as the patellar ridge surpassing the apex of the lateral femoral trochlea. Patients were evaluated using the Kujala, International Knee Documentation Committee (IKDC), and Lysholm scores preoperatively and postoperatively. Patients were allocated into 3 subgroups in terms of the severity of the J sign: low-grade group 1 (grade 1; n = 19), low-grade group 2 (grade 2; n = 16), and high-grade group (grade 3; n = 12). Subgroup analyses were performed to investigate the influence of a high-grade J sign on the clinical outcomes. Results: Among the 78 patients (81 knees), 47 patients (47 knees) met the inclusion criteria. The mean follow-up time was 26.1 ± 1.7 months. The mean preoperative and postoperative FAAs were 36.2°± 5.3° and 10.0°± 2.1°, respectively, with a mean correction angle of 26.2°± 5.9°. At the final follow-up, all patient-reported outcomes improved significantly, and subgroup analyses showed that the high-grade group had significantly lower Kujala scores (75.6 vs 85.3 for low-grade group 1 [ P < .001] and 83.4 for low-grade group 2 [ P = .001]), Lysholm scores (77.6 vs 84.6 for low-grade group 1 [ P = .003]), and IKDC scores (78.6 vs 87.3 for low-grade group 1 [ P = .001] and 84.3 for low-grade group 2 [ P = .033]) than the low-grade groups. The total rate of MPFL residual graft laxity was 8.5% (4/47), and the prevalence of the postoperative residual J sign was 38.3% (18/47). Subgroup analyses showed significant differences between the high-grade group and the 2 low-grade groups with regard to the MPFL residual graft laxity rate (33.3% vs 0.0% for low-grade group 1 [ P = .016] and 0.0% for low-grade group 2 [ P = .024]), residual J sign rate (91.7% vs 15.8% for low-grade group 1 [ P < .001] and 25.0% for low-grade group 2 [ P < .001]), and patellar lateral shift distance (14.2 vs 8.1 mm for low-grade group 1 [ P = .002] and 8.7 mm for low-grade group 2 [ P = .007]). Conclusion: In a group of patients treated for RPD with a positive preoperative J sign and increased FAA (≥30°), patients with a preoperative high-grade J sign had inferior clinical outcomes, more MPFL residual graft laxity, and greater residual patellar maltracking.

Objective:To explore the risk factors of primary anterior cruciate ligament (ACL) reconstruction failure.Methods:From November 2015 to May 2017, a total of 178 consecutive patients with clinically diagnosed non-contact ACL injury were treated and followed-up more than 2 years. Twenty-five patients (post-operative failure group) who underwent completely ruptured ACL graft confirmed by MRI, positive pivot-shift test, more than 5 mm side-to-side difference (SSD) measured by KT-1000 arthrometer, more than 5 mm static anterior tibial translation (ATT) measured on MRI were determined to be ACL reconstruction failure. They were matched in a 1∶2 fashion to 50 non-failure patients (post-operative non-failure group), who showed intact ACL graft 2 years after ACL reconstruction. The sex, age, body mass index (BMI), affected side, meniscal injury side, time from injury to surgery, KT-1000 SSD, pivot shift test under anesthesia, follow-up duration, posterior tibial slope (PTS) and ATT measured on the pre-operative weight-bearing whole leg radiographs between the two groups were compared using univariate analysis. Moreover, the predictors of ACL reconstruction failure were assessed by multivariable conditional Logistic regression analysis.Results:Post-operative failure group had a significantly higher PTS and ATT values than those in the post-operative non-failure group (17.21°±2.20° vs 14.36°±2.72°, t=4.395, P<0.001; 8.29±3.42 mm vs 4.09±3.06 mm, t=5.504, P<0.001). The sex, age, BMI, affected side, meniscal injury side, time from injury to surgery, KT-1000 SSD, pivot shift test under anesthesia, follow-up duration between the two groups showed no significant difference ( P>0.05). Multivariable Logistic regressions indicated that PTS≥17° ( OR=15.62, P=0.002) and ATT≥6 mm ( OR=9.91, P=0.006) were independent risk factors for primary ACL reconstruction failure. However, sex, age, BMI, meniscal lesions, degree of pivot shift test, KT-1000 SSD were not the independent risk factors. Conclusion:PTS≥17° and ATT≥6 mm could increase the risk of primary ACL reconstruction failure.

Background/Objective: The treatment of anterior cruciate ligament (ACL) partial tear is controversial. The reconstructive surgery is invasive while the prevalence of subsequent insufficiency after conservative treatment has been reported to range from 11% to 62%. Therefore, a new method that promotes tissue regeneration is needed. The aim of this study was to observe the healing of ACL partial tear biomechanically and histologically after the administration of a thermosensitive hydrogel platelet-rich-plasma (PRP) complex. Methods: The complex was prepared according to a previously published protocol. One hundred and fifty 12-week-old male Sprague-Dawley rats were included and they were allocated into 4 groups. Lesion control group (Group 1), treatment group (Group 2), gel-only group (Group 3) and intact group (Group 4). Biomechanical testing, histological analysis (H&E and immunohistochemical staining) and scoring was performed. Results: On gross observation, the treatment group showed a continuous ACL with slightly thickened synovium or a partially healed ACL at 6-week follow up. In the biomechanical testing at 6 weeks after surgery, the failure load of the treatment group was significantly superior when compared with the lesion control group (52.7±10.8N vs. 41.6±7.8N, p<0.01), but the failure load was not restored to level of the intact group (52.7±10.8N vs. 61.5±9.1N, p=0.037). The maturity index of wound sites showed no significant inter-group differences at any timepoints. However, an increased expression of vascular endothelial growth factor (VEGF) and pro-collagen I was detected. Conclusion: The thermosensitive hydrogel-PRP was shown to be effective in enhancing the healing of ACL partial tear in the rat model, and potentially this complex can be used as a treatment for patients with ACL partial tear. The translational potential of this article: The thermosensitive hydrogel-PRP is potentially translated to clinical use to treat patients with ACL partial tear by injection under arthroscopy or ultrasound guiding.

Background: Habitual patellar dislocation in extension (HPD-E) is a distinctive subtype of recurrent patellar dislocation (RPD); HPD-E represents the most severe type of patellar maltracking in RPD. It has been reported that the presence of preoperative patellar maltracking is associated with a worse clinical outcome after medial patellofemoral ligament (MPFL) reconstruction (MPFL-R). Purpose: To describe the radiological characteristics of HPD-E and to compare clinical outcomes after MPFL-R among patients with and without preoperative HPD-E. Study Design: Cohort study; Level of evidence, 3. Methods: From January 2012 to December 2015, a total of 230 consecutive patients (246 knees) with RPD were treated with MPFL-R alone or combined with tibial tubercle osteotomy. Among them, 28 patients diagnosed with HPD-E by preoperative 3-dimensional computed tomography (CT; HPD-E group) were matched in a 1:1 fashion to 28 control participants who did not show HPD-E (control group). Routine radiography and CT were performed to evaluate patellar height, trochlear dysplasia, tibial tubercle–trochlear groove distance, and torsional deformities. The mean patellar laxity index and lateral patellar translation assessed with stress radiography were measured preoperatively and postoperatively to quantify MPFL laxity. At minimum 2-year follow-up, patient-reported outcomes (Kujala, Lysholm, and Tegner scores), patellar maltracking, and redislocation rates were compared between the HPD-E and control groups. Results: The radiological characteristics of the HPD-E group were as follows: 89% (25/28) of patients had severe trochlear dysplasia (Dejour type B or D), and the mean femoral anteversion angle was 35.5° ± 4.7°. At the final follow-up, the HPD-E group had a significantly lower Kujala score (76.2 vs 84.5, respectively; P = .001), Lysholm score (75.4 vs 86.6, respectively; P < .001), and Tegner score (4.1 vs 5.8, respectively; P = .021) compared with the control group. The postoperative patellar laxity index (43% vs 19%, respectively; P < .001) and redislocation rate (25% vs 0%, respectively; P = .01) were significantly higher in the HPD-E group than in the control group. Conclusion: Preoperative 3-dimensional CT is a reliable method of identfying patients with HPD-E. Treatment of HPD-E by MPFL-R alone or combined with tibial tubercle osteotomy resulted in a higher redislocation rate, more severe MPFL residual laxity, and lower patient-reported outcome scores compared with patients without HPD-E who underwent MPFL-R.

BACKGROUND:Anterior tibial subluxation (ATS) in extension after anterior cruciate ligament (ACL) injury highlights an increased anterior position of the tibia relative to the femur. Recent studies demonstrated that subluxation is sometimes irreducible and the normal tibiofemoral relationship is not restored by ACL reconstruction (ACLR), which raises concerns regarding clinical outcomes after ACLR. HYPOTHESIS:Excessive preoperative ATS in extension is associated with inferior knee stability after anatomic ACLR. STUDY DESIGN:Cohort study; Level of evidence, 3. METHODS:From March 2016 to January 2017, a total of 487 consecutive patients with clinically diagnosed noncontact ACL injuries who underwent primary anatomic ACLR were retrospectively analyzed. Of these patients, 430 met the criteria for inclusion in this study. Anterior subluxation of the lateral and medial compartments (ASLC and ASMC) in extension relative to the femoral condyles was measured on preoperative magnetic resonance imaging. Twenty patients (study group) who demonstrated excessive (>10 mm) ASLC and ASMC in extension were matched 1:2 to 40 participants (control group) who showed minimal or no (<3 mm) ASLC and ASMC in extension. The amount of ASLC and ASMC in extension relative to the femoral condyles at 2 years postoperatively was the primary outcome. Moreover, the Lysholm score, IKDC grade (International Knee Documentation Committee), and stability assessments (pivot-shift test and KT-1000 arthrometer side-to-side difference) were evaluated preoperatively and at the last follow-up visit. RESULTS:The preoperative mean ASLC and ASMC in extension of the study group were both significantly larger than those of the control group (study group vs control group: ASLC, 13.5 mm vs 1.2 mm; ASMC, 12.4 mm vs 1.0 mm; P < .05). Moreover, patients in the study group showed significantly larger posterior tibial slope than the patients in the control group (17.8°± 2.5° vs 9.5°± 1.5°; P < .05). At the final follow-up visit, the mean ASLC and ASMC of the study group were 8.1 mm and 7.3 mm, which were significantly larger than those of the control group (ASLC, 0.9 mm; ASMC, 0.7 mm; P < .05). In addition, the study group showed inferior knee stability when compared with the control group in terms of both the pivot-shift test (study group vs control group: 2 grade 2, 10 grade 1, and 8 grade 0 vs 1 grade 1 and 39 grade 0; P < .05) and the KT-1000 arthrometer side-to-side difference (study group vs control group: 4.4 ± 1.2 mm vs 1.5 ± 0.6 mm; P < .05). Furthermore, the study group showed significantly lower mean Lysholm score (study group vs control group: 80.3 ± 6.3 vs 93.3 ± 4.3, P < .05) and IKDC grading results (study group vs control group: 3 grade C, 16 grade B, and 1 grade A vs 3 grade B and 37 grade A; P < .05) as compared with the control group. CONCLUSION:In this short-term study, the excessive (>10 mm) preoperative ATS in extension after ACL injury was associated with inferior knee stability after anatomic ACLR.

Objective:To evaluate the clinical, radiological and arthroscopic outcomes after surgical repair for chronic lateral meniscus posterior root (LMPR) avulsion combined with anterior cruciate ligament (ACL) reconstruction.Methods:From July 2015 to June 2017, a total of 33 patients who underwent transtibial pull-out suture repair for chronic LMPR avulsion combined with anatomic single-bundle ACL reconstruction with hamstring graft were retrospectively reviewed. There were 30 males and 3 females with an average age of 27.7±7.5 years (range 17-45 years) and a mean BMI of 25.2±3.7 kg/m 2 (range 19.4-36.7 kg/m 2). All patients were available for at least two years of follow-up. A second-look arthroscopy was performed to evaluate the healing status of the repaired meniscus. Subjective knee function was assessed through Lysholm and Tegner scores. Objective knee stability was evaluated using KT-1000 arthrometer side-to-side difference (SSD) and pivot shift test under anesthesia. The tibiofemoral relationship was evaluated by anterior tibial subluxation (ATS) measured on axial MRI. Between patients with preoperative ATS ≥6 mm (18 patients in the ATS positive group) and <6 mm (15 patients in the ATS negative group), the postoperative ATS and the reduction of ATS was also compared. Results:After a mean follow-up of 27.5±4.0 months (range 24-39 months), the LMPR avulsion completely healed in 23 (70%) cases, partially healed in 9 (27%) cases, failed to heal in 1 (3%) case on second-look arthroscopy. The Lysholm score was increased from 60.4±13.6 to 82.7±11.1 at 1 year and to 91.4±9.1 at 2 years operatively ( F=155.996, P<0.001). The Tegner score was increased from 3(2, 5) to 4(3, 5) at 1 year and 6(4, 6) at 2 years postoperatively (χ 2=47.791, P<0.001). The KT-1000 SSD was decreased from 9.1±3.3 mm to 2.0±1.7 mm ( t=11.197, P<0.001). The result of pivot shift test was also improved (10 grade I, 20 grade II, 3 grade III, preoperatively vs 30 grade 0, 3 grade I, postoperatively, U=5.161, P<0.001). The ATS was reduced from 5.7±3.9 mm to 3.5±3.2 mm ( t=3.530, P=0.001). However, there was no statistically significant decrease in the ATS of the ATS negative group ( t=0.400, P=0.695). The ATS of the ATS positive group was reduced from 8.7±1.8 mm to 5.0±3.3 mm ( t=4.765, P<0.001), and the ATS reduction of the ATS positive group was greater than that of the ATS negative group (3.7±3.3 mm vs 0.3±2.8 mm, t=3.115, P=0.004). Conclusion:In patients undergoing ACL reconstruction, the transtibial pull-out suture repair for chronic LMPR avulsion yielded meniscus healing rate of 97% with improved subjective knee function and objective knee stability and better restored the tibiofemoral relationship for patients with excessive ATS.