Recurrent patellar dislocation patients with high-grade J-sign have multiple structural bone abnormalities in the lower limbs.

PURPOSE: To explore the relationship between preoperative J-sign grading and structural bone abnormalities in patients with recurrent patellar dislocation (RPD). METHODS: A retrospective study was conducted on RPD patients over 5 years. Patients were categorised based on J-sign grade into low (J- and J1+), moderate (J2+) and high groups (J3+). Trochlear dysplasia (TD) and osseous structures (femoral anteversion angle [FAA], knee torsion, tibial tuberosity-trochlear groove [TT-TG] distance, Caton-Deschamps index) were assessed and grouped according to risk factor thresholds. The χ2 test was used to compare composition ratio differences of structural bone abnormalities among the groups. RESULTS: A total of 256 patients were included, with 206 (80.5%) females. The distribution of J-sign grade was as follows: 89 knees (34.8%) of low grade, 86 moderate (33.6%) and 81 high (31.6%). Among the five structural bone abnormalities, TD was the most common with a prevalence of 78.5%, followed by increased TT-TG at 47.4%. Excessive tibiofemoral rotation had the lowest occurrence at 28.9%. There were 173 (67.6%) patients who had two or more abnormalities, while 45 (17.6%) had four to five bony abnormalities. Among patients with any bony abnormality, the proportion of high-grade J-sign surpassed 40%. Patients with moderate and high-grade J-sign had more increased FAA and more pronounced patella alta (all p < 0.001). The proportion of excessive knee torsion and TD increased with increasing each J-sign grade, with the more notable tendency in knee torsion (high vs. moderate vs. low-grade: 61% vs. 22% vs 7%, p < 0.001). Furthermore, the higher J-sign grade was also associated with more combined bony abnormalities (p < 0.001). In the high-grade J-sign group, 90.2% of the knees had two or more bony risk factors and 40.7% had four or more, which were significantly higher than the moderate and low-grade J-sign groups (40.7% vs. 11.6% vs. 2.2%, p < 0.001). CONCLUSION: In patients with a high-grade J-sign, over 90% of the lower limbs had two or more structural bone risk factors, and more than 40% had four or more. These proportions were significantly higher compared to knees with low-grade and moderate J-sign. In clinical practice, when treating high-grade patellar mal-tracking, it is important to focus on and correct these strongly correlated abnormal bone structures. LEVEL OF EVIDENCE: Level III.

The clinical outcome of minimally invasive popliteal tendon recess procedure is comparable to arthroscopic popliteal tendon reconstruction in patients with type A posterolateral rotational instability.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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. LEVEL OF EVIDENCE: III.

Derotational distal femoral osteotomy yields satisfactory clinical outcomes in pathological femoral rotation with failed medial patellofemoral ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the clinical outcomes of de-rotational distal femoral osteotomy (DDFO) in patients who underwent primary medial patellofemoral ligament reconstruction (MPFLR) failure with increased femoral anteversion along with high-grade J sign. METHODS: Between 2011 and 2019, 14 patients underwent DDFO revision surgery due to failed MPFLR. The pre- and postoperative J sign grade, Caton-Deschamps index (CDI), tibial tuberosity-trochlear groove (TT-TG) distance, femoral anteversion angle (FAA), patellar lateral tilt angle (PLTA), MPFL graft laxity, and patient-reported outcomes (Kujala, Lysholm, Tegner, and International Knee Documentation Committee (IKDC) subjective scores) were collected. The anterior-posterior and proximal-distal distances between the actual point and the Schöttle point were also calculated. RESULTS: Fourteen patients underwent MPFLR revision by DDFO combined with MPFLR. The mean PLTA improved from 40.7° ± 11.9° to 20.5° ± 8.7° (P < 0.001). The mean FAA significantly decreased from 42.7° ± 12.0° to 14.1° ± 5.2° (P < 0.001). The mean patellar laxity index (PLI) decreased from 82.4% preoperatively to 15.1% postoperatively (P < 0.001). None of these patients experienced subluxation or re-dislocation during follow-up of 29.7 ± 5.0 months after revision surgery. Meanwhile, the Tegner score at the last follow-up ranged from 3 to 6, with a median of 5. The Kujala, Lysholm, and IKDC subjective scores showed significant improvements, from a mean of 51.0 ± 6.8 preoperatively to 75.4 ± 5.1 postoperatively (P < 0.001), 49.2 ± 7.9 to 75.2 ± 7.2 (P < 0.001), and 42.9 ± 6.2 to 76.8 ± 6.0 (P < 0.001), respectively. The proportion of patients with a high-grade J sign was significantly lower postoperatively than preoperatively (100% vs. 14%). Four out of 14 patients (29%) showed femoral tunnel mal-positioning. CONCLUSION: MPFLR revision by DDFO combined with MPFLR achieved favorable clinical outcomes in patients with increased femoral anteversion along with high-grade J sign. LEVEL OF EVIDENCE: IV.

Posterior tibial slope measurements based on the full-length tibial anatomic axis are significantly increased compared to those based on the half-length tibial anatomic axis.

PURPOSE: This study aimed to compare the difference in posterior tibial slope (PTS) measurements based on the full-length and half-length tibial anatomic axes of the same group of patients. It was hypothesized that the obtained PTS values would be affected by the length of tibia chosen during the measurements. METHODS: Full-length true lateral tibia radiographs were obtained for each patient who underwent anterior cruciate ligament reconstruction (ACLR) in our department. PTS measurements were obtained by measuring the angle between the full-length or half-length tibial anatomic axis and an average of the lateral and medial tibial plateau. The anatomic axis was defined as the center of the tibial diaphysis. The PTS measurements from the full-length and half-length true lateral tibia radiographs were obtained and compared. Additionally, the absolute difference and the relationship between the two PTS measurements were calculated and analyzed. RESULTS: A total of 200 ACL-injured patients were included in this study. The average PTS values using the anatomic axis were 15.9 ± 3.7° and 14.1 ± 3.7° on full-length and half-length true lateral tibial radiographs. There was a significant difference between the measurements with the full-length and half-length tibial radiographs (P < 0.01). Additionally, 49.5% (n = 99) of patients had ≥ 2.0° differences between the full-length and half-length anatomic axis PTS measurement techniques; meanwhile, a strong and significant linear relationship (r = 0.95; P < 0.001) was identified between the two PTS measurements. CONCLUSION: There were significant differences and linear relationships between PTS measurements that measured the anatomic axis from full-length and half-length true lateral tibia radiographs. Therefore, the obtained PTS values were strongly associated with the length of tibia chosen during the measurements. Surgeons should pay more attention to the measurement techniques and the tibial length when considering the role of PTS in ACL injury and ACLR failure. Knowledge of the association is very important for calculating potential closing wedge proximal tibial osteotomies to correct excessive PTS in the setting of ACLR failures. LEVEL OF EVIDENCE: IV.

The presence of a preoperative high-grade J-sign and femoral tunnel malposition are associated with residual graft laxity after MPFL reconstruction.

PURPOSE: 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). METHODS: 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. RESULTS: 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. CONCLUSION: 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 OF EVIDENCE: Level III.

Assessment of Tendon Retraction in Large to Massive Rotator Cuff Tears: A Modified Patte Classification Based on 2 Coronal Sections on Preoperative Magnetic Resonance Imaging With Higher Specificity on Predicting Reparability.

PURPOSE: To propose a modified Patte classification (evaluating tendon retraction on 2 coronal sections) and analyze whether this classification was better at predicting irreparability and retear of large to massive rotator cuff tears (RCTs). METHODS: A retrospective study was performed. Imaging evaluation including tendon retraction, fatty infiltration, the acromiohumeral distance (AHD), and the tangent sign was performed using magnetic resonance imaging. The modified Patte classification was used to assess tendon retraction. Intraobserver and interobserver reliability was analyzed by calculating intraclass correlation coefficients. Factors affecting irreparability and retear were analyzed using both univariate and multivariate analyses. Sensitivity and specificity of tendon retraction to predict irreparability and retear were calculated. RESULTS: A total of 121 shoulders with large to massive RCTs underwent arthroscopic rotator cuff repairs. The modified Patte classification system had excellent interobserver and intraobserver reliability. Several factors were associated with reparability and retear in the univariate analysis. However, in binary logistic regression analysis, the only factors affecting reparability were AHD less than 0.4 cm (P = .007) and modified Patte stage III tendon retraction (P = .023). Low-grade repair quality (P = .001) and modified Patte stage III tendon retraction (P = .031) were independent factors for retear. Modified Patte stage III had a high specificity for predicting irreparability (93.58%) and retear (98.78%), whereas the specificity of original Patte stage III was 76.15% and 84.15%, respectively. CONCLUSIONS: For large to massive RCT repairs, modified Patte stage III tendon retraction with evaluation of 2 coronal cuts reveals higher specificity on predicting tendon irreparability and postoperative retear. An AHD less than 0.4 cm on magnetic resonance imaging and modified Patte stage III tendon retraction were independent risk factors for irreparability. Low-grade repair quality and modified Patte stage III tendon retraction were independent risk factors for postoperative retear. LEVEL OF EVIDENCE: Level III, case-control study.

Increased femoral anteversion is associated with inferior clinical outcomes after MPFL reconstruction and combined tibial tubercle osteotomy for the treatment of recurrent patellar instability.

PURPOSE: This study aimed at investigating the influence of an increased femoral anteversion angle on clinical outcomes after medial patellofemoral ligament reconstruction and combined tibial tubercle osteotomy for the treatment of recurrent patellar instability. It was hypothesized that an increased femoral anteversion is associated with inferior clinical outcomes. METHODS: From 2014 to 2016, a total of 144 consecutive patients with recurrent patellar instability were treated with medial patellofemoral ligament reconstruction and combined tibial tubercle osteotomy. The femoral anteversion angle was measured using three-dimensional computed tomography scans. Patients were allocated into group A (femoral anteversion < 20°), group B (femoral anteversion 20°-30°) and group C (femoral anteversion > 30°) based on the value of the femoral anteversion angle. Routine radiography and CT examinations were performed to evaluate the patellar height, trochlear dysplasia, genu valgum, and tibial tuberosity-trochlear groove (TT-TG) distance. The patellar lateral shift distance assessed with stress radiography was used pre- and postoperatively to quantify medial patellofemoral ligament residual laxity under anaesthesia. Patient-reported outcomes (Kujala, IKDC, and Lysholm scores) and patellar maltracking ("J-sign") were evaluated pre- and postoperatively. Finally, subgroup analysis was performed to investigate the influence of an increased femoral anteversion angle on the clinical and radiological outcomes. RESULTS: A total of 66 patients (70 knees) were included with a median follow-up time of 28 months (range 24-32). After a minimum of 2 years of follow-up, all patient-reported outcomes (Kujala, Lysholm, and IKDC scores) improved significantly, and subgroup analysis showed that group C had significantly lower Kujala scores (75 ± 8 vs. 84 ± 8, P13 = 0.003; 75 ± 8 vs. 82 ± 8, P23 = 0.030), Lysholm scores (81 ± 9 vs. 87 ± 7, P13 = 0.021) and IKDC scores (78 ± 6 vs. 85 ± 7, P13 = 0.001; 78 ± 6 vs. 84 ± 6, P23 = 0.005) than group A and group B. Twelve patients had a postoperative residual J-sign (17.1%), and significant differences were found between group C and group A regarding the rate of residual J-sign (32.1% vs. 4.8%, P13 = 0.003). Postoperatively, group C had a greater patellar lateral shift distance than group A (10 ± 4 vs. 6 ± 4 mm, P13 = 0.006) and group B (10 ± 4 vs. 6 ± 3 mm, P23 = 0.008). Additionally, patients with a residual J-sign demonstrated greater medial patellofemoral ligament laxity than patients without a residual J-sign (12 ± 4 vs. 9 ± 3 mm, P = 0.009). CONCLUSION: Patients with an increased femoral anteversion angle (> 30°) had inferior postoperative clinical outcomes, including greater patellar laxity, a higher rate of residual J-sign and lower patient-reported outcomes after medial patellofemoral ligament reconstruction and combined tibial tubercle osteotomy for the treatment of recurrent patellar instability. LEVEL OF EVIDENCE: III, retrospective cohort study.

A pre-operative grade 3 J-sign adversely affects short-term clinical outcome and is more likely to yield MPFL residual graft laxity in recurrent patellar dislocation.

PURPOSE: The purposes of this study were to investigate the anatomical risk factors of grade 3 J-sign and analyse the influence of J-sign grades on the short-term clinical outcomes of patients with recurrent patellar dislocation. METHODS: From 2016 to 2018, a total of 168 patients with recurrent patellar dislocation (187 knees) underwent medial patellofemoral ligament reconstruction with or without tibial tuberosity medialization. Pre-operative J-sign severity was graded according to a previously described classification (grades 1-3). Potential anatomical risk factors of J-sign were explored. Comparisons were assessed between patients with different grades of J-sign using univariate and binary logistic regression analyses. The Kujala score was assessed and compared with pre-operative values, and stress fluoroscopy was performed to assess medial patellofemoral ligament residual graft laxity. Among the 130 included cases, 104 knees with at least 1-year follow-up were included in the clinical outcome analyses to explore the influence of several anatomical factors and J-sign grade on short-term clinical outcomes. RESULTS: A total of 118 patients (130 knees) were included in the present study. The median age at surgery was 21 years (range 13-38), and 111 affected knees belonged to female patients (85%). Univariate and multivariate logistic regressions between the grade 3 group and the grade 1-2 groups showed that increased femoral anteversion, excessive external tibial torsion, and patella alta were three independent risk factors of grade 3 J-sign in patients with recurrent patellar dislocation. A total of 104 knees with at least a 1-year follow-up were included in the clinical outcome analyses. The median Kujala score improved from 54 (range, 38-72) pre-operatively to 86 (range, 70-100) post-operatively. Although no re-dislocation was reported during the follow-up, 6 out of 32 patients in the grade 3 group demonstrated "MPFL residual graft laxity" based on post-operative stress radiography (18.8%), which was significantly higher than in the grade 1-2 groups (0%, p < 0.001). Subgroup analysis showed that patients with grade 3 J-sign had significantly lower post-operative Kujala scores than those with grade 1-2 J-sign (p < 0.001). Moreover, increased femoral anteversion (≥ 30°) was correlated with an inferior post-operative Kujala score (p = 0.023). CONCLUSION: The three independent anatomic risk factors of grade 3 J-sign in patients with recurrent patellar dislocation were increased femoral anteversion, excessive external tibial torsion, and patella alta. A pre-operative grade 3 J-sign was correlated with a lower post-operative Kujala score and more "MPFL residual graft laxity" in patients with recurrent patellar dislocation treated with MPFL reconstruction with or without tibial tuberosity medialization at a minimum 1-year follow-up. LEVEL OF EVIDENCE: III.

Excessive lateral patellar translation on axial computed tomography indicates positive patellar J sign.

PURPOSE: The purpose of the study was to quantify the patellar J sign using traditional computed tomography (CT) scans. METHODS: Fifty-three patients (fifty-three knees) who suffered from recurrent patellar instability were included and analyzed. The patellar J sign was evaluated pre-operatively during active knee flexion and extension. It was defined as positive when there was obvious lateral patellar translation, and negative when there was not. The CT scans were performed in all patients with full knee extension; and the parameters including bisect offset index (BOI), patellar-trochlear-groove (PTG) distance, and patellar lateral tilt angle (PLTA) were measured on the axial slices. All the three parameters were compared between the J sign-positive group (study group) and the J sign-negative group (control group). In addition, the optimal thresholds of the three CT scan parameters for predicting the positive patellar J sign were determined with receiver operating characteristic (ROC) curves, and the diagnostic values were assessed by the area under the curve (AUC). RESULT: Among the fifty-three patients (fifty-three knees), thirty-seven (70%) showed obvious lateral patellar translation, which were defined as positive J sign (study group), and the remaining sixteen (30%) who showed no lateral translation were defined as negative J sign (control group). The mean values of the three CT parameters in the study group were all significantly larger compared to the control group, including BOI (121 ± 28% vs 88 ± 12%, P = 0.038), PTG distance (5.2 ± 6.6 mm vs - 4.4 ± 5.2 mm, P < 0.05), and PLTA (34.9 ± 10.5° vs 25.7 ± 3.4°, P = 0.001). Furthermore, the evaluation of ROC analysis showed that the AUC of BOI was the largest (AUC = 0.906) among the three parameters, and the optimal threshold of BOI to predict the positive patellar J sign was 97.5% (Sensitivity = 83.3%, Specificity = 87.5%). CONCLUSIONS: In this study, the prevalence of positive patellar J sign was 70%. The BOI measured from the axial CT scans of the knee joint can be used as an appropriate predictor to differentiate the positive J sign from the negative J sign, highlighting that the excessive lateral patellar translation on axial CT scan indicates positive patellar J sign. LEVEL OF EVIDENCE: IV.

Arthroscopic Latarjet Procedure With Anterior Capsular Reconstruction: Clinical Outcome and Radiologic Evaluation With a Minimum 2-Year Follow-Up.

PURPOSE: To investigate the clinical and radiographic outcomes of the modified arthroscopic Latarjet procedure at a minimum of 2 years after surgery. METHODS: Patients who had traumatic unidirectional anterior shoulder instability and treated with a modified arthroscopic Latarjet procedure were included. During surgery, the anterior capsule was preserved and repaired back to the glenoid after the coracoid transfer. The clinical results (range of motion, American Shoulder and Elbow Surgeons [ASES] score, Constant-Murley score, and Rowe score) and computed tomographic results were followed. RESULTS: From February 2013 to September 2014, 52 consecutive patients were included. The average duration of follow-up was 28.4 months (range, 24.0-41.7 months). At final follow-up, no recurrent dislocation had occurred. The ASES score and Rowe score improved significantly (ASES score from 85.6 ± 12.7 before surgery to 93.6 ± 5.4 after surgery, P < .0001; Rowe score from 41.5 ± 7.2 before surgery to 92.2 ± 8.7 after surgery, P < .0001). No significant change was found regarding range of motion and the Constant-Murley score. Bone union was achieved in all cases. The transferred coracoid was at the level of the glenoid in all cases. The transferred coracoid was placed below the equator in 48 of 52 cases (92.3%). The orientation of the screw was 22.6° ± 10.8°. Bone resorption around the proximal screw was significantly more prominent than that around the distal screw (P < .0001). CONCLUSIONS: The arthroscopic Latarjet procedure with concomitant anterior capsular reconstruction can achieve satisfactory clinical outcomes for the treatment of anterior shoulder instability with marked glenoid bone loss at a minimum of 2 years' follow-up. A satisfactory coracoid graft position, proper screw orientation, and high healing rate of the transferred coracoid can be expected. Bone resorption around the proximal screw is more severe than that around the distal screw. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Complete posterolateral meniscal root tear is associated with high-grade pivot-shift phenomenon in noncontact anterior cruciate ligament injuries.

PURPOSE: The purpose of this study was to investigate whether the complete posterolateral meniscal root tear (PLMRT) would be associated with high-grade pivot-shift phenomenon in noncontact anterior cruciate ligament (ACL) injuries. METHODS: From 2013 to 2015, a total of 1095 consecutive patients were diagnosed as having noncontact ACL injuries and underwent primary ACL reconstructions. Among them, 140 patients were arthroscopically verified to have concomitant PLMRTs. Application of the exclusion criteria finally left 74 patients who were finally allocated into high-grade pivot-shift (grades II and III) group (n = 51) and low-grade pivot-shift (grades 0 and I) group (n = 23) according to the results of pre-operative pivot-shift tests performed under anesthesia. Predictors of high-grade pivot-shift phenomenon, including degree of PLMRTs, integrity of posterior MFLs, status of lateral meniscal extrusion, age, sex, body mass index (BMI), and KT-1000 arthrometer side-to-side difference (SSD), were assessed by multivariable logistic regression analysis. RESULTS: The proportion of patients with complete PLMRT in high-grade pivot-shift group was significantly larger than that in low-grade pivot-shift group. In addition, complete PLMRT was significantly [odds ratio (OR) 4.044; 95% CI 1.125-14.534; P = 0.032] associated with high-grade pivot-shift phenomenon in noncontact ACL injury, especially for those with a time from injury to surgery of ≥12 weeks (OR 16.593; 95% CI 1.073-56.695; P = 0.014). However, no significant association was identified between neither the integrity of posterior MFLs nor the status of lateral meniscal extrusion and the high-grade pivot-shift phenomenon. CONCLUSION: Complete PLMRT is identified to be an independent risk factor of high-grade pivot-shift phenomenon in noncontact ACL injuries, particularly for those with a time from injury to surgery of ≥12 weeks. LEVEL OF EVIDENCE: IV.

Patients with high-grade pivot-shift phenomenon are associated with higher prevalence of anterolateral ligament injury after acute anterior cruciate ligament injuries.

PURPOSE: To compare the prevalence of concomitant anterolateral ligament (ALL) injury between patients with high-grade (grades II and III) pivot-shift and those with low-grade (grades 0 and I) pivot-shift phenomenon after acute anterior cruciate ligament (ACL) injuries. METHODS: Sixty-eight patients with an acute ACL injury who showed high-grade (grades II and III) pivot-shift phenomenon were enrolled as the study group. They were matched in a 1:1 fashion to another 68 ACL-injured control participants who showed low-grade (grades 0 and I) pivot-shift phenomenon during the same study period. Patients were matched by age, sex, and time from injury to surgery. A standardized pivot-shift test was performed under anesthesia for all the patients. Two blinded musculoskeletal radiologists reviewed the magnetic resonance imaging (MRI) scans for the presence of concomitant ALL injury. The grade of an ALL injury was divided into grade 0 (normal), grade I (sprain), grade II (partial tear), and grade III (complete tear). The prevalence and the grade of concomitant ALL injury were further compared between the study group and the control group. RESULTS: Overall, the prevalence of concomitant ALL injury in the study group (94.1%, 64/68) was significantly higher than that in the control group [60.3%, (41/68), P < 0.05]. Specifically, there were 49 patients (49/64, 76.6%) who showed grade II/III (partial/complete tear) MRI evidence of concomitant ALL injury, which was also significantly higher than that in the control group (12/41, 29.3%). CONCLUSIONS: Patients with high-grade pivot-shift phenomenon showed higher prevalence of concomitant ALL injury compared to those with low-grade pivot-shift phenomenon after acute ACL injuries. Careful assessment and proper treatment of this concomitant injury should be considered especially in knees with high-grade pivot-shift phenomenon. LEVEL OF EVIDENCE: III.

Clinical Outcomes of Combined Lateral Extra-articular Tenodesis and Intra-articular Anterior Cruciate Ligament Reconstruction in Addressing High-Grade Pivot-Shift Phenomenon.

PURPOSE: To evaluate the clinical outcomes of combined lateral extra-articular tenodesis (LET) and intra-articular anterior cruciate ligament (ACL) reconstruction (ACLR) in addressing the high-grade pivot-shift phenomenon. METHODS: The PubMed/Medline database was searched for articles reporting clinical outcomes of combined LET and intra-articular ACLR in treating ACL injuries with high-grade pivot shift. High-grade pivot shift was defined as the presence of moderate to severe rotational instability shown by a grade II or III manual pivot shift preoperatively (grade 0, normal; grade I, glide; grade II, clunk; and grade III, locking, according to International Knee Documentation Committee [IKDC] form). The postoperative manual pivot-shift grading during the clinical follow-up visit was the primary outcome variable. Moreover, the prevalence of residual pivot shift (grade I, II, or III), distribution of objective IKDC scores, and anterior knee stability were also compared between patients with and without an additional LET procedure. RESULTS: Seven studies were included. Overall, 326 patients (326 knees) with high-grade pivot shift underwent combined LET and intra-articular ACLR with a mean follow-up period of 46.2 months (range, 24 to 76 months). There were 274 patients (84.1%) with grade 0, 42 (12.9%) with grade I, and 10 (3.0%) with grade II pivot shift at the final follow-up. Among the 5 comparative studies, the prevalence of residual pivot shift was significantly lower (P < .05) in patients with LET plus ACLR (13.3%, 30 of 226) than those with isolated ACLR (27.2%, 67 of 246). However, the distribution of objective IKDC scores and anterior knee stability showed no significant differences between groups. CONCLUSIONS: The combination of LET and intra-articular ACLR was effective in eliminating the high-grade pivot-shift phenomenon. For ACL injuries with high-grade pivot shift, LET plus ACLR provided a significant reduction in the prevalence of residual pivot shift but no differences in objective IKDC scores and anterior knee stability compared with isolated ACLR at short-term follow-up. LEVEL OF EVIDENCE: Level IV, systematic review of Level I, III, and IV studies.

Biomechanical and Biological Findings Between Acute Anterior Cruciate Ligament Reconstruction With and Without an Augmented Remnant Repair: A Comparative in Vivo Animal Study.

PURPOSE: To investigate whether remnant-preserving anterior cruciate ligament reconstruction (ACLR) for acute complete anterior cruciate ligament (ACL) tears can improve the biomechanical strength, revascularization status, and proprioceptive recovery potential of the grafted tendons compared with conventional ACLR. METHODS: An acute complete ACL femoral detachment model was created in 60 rabbits. The animals were randomly allocated into the remnant-repairing ACLR group (group 1, n = 30) or the conventional ACLR group (group 2, n = 30). The ACL remnants were either acutely repaired with a femoral tensioning technique in group 1 or completely debrided in group 2. For group 1, remnant structural integrity was evaluated macroscopically and divided into grade A (bridging femur and tibia) and grade B (not bridging femur and tibia). Then, the remnant-to-graft healing capacity was assessed histologically. For intergroup comparisons, the biomechanical strength of the grafted tendons was evaluated by tensile tests and the revascularization status (vascular endothelial growth factor) and proprioceptive recovery potential (neurofilament) of the grafted tendons were evaluated by immunofluorescent staining. All assessments were performed postoperatively at week 24. RESULTS: In group 1, 60% of remnants (18 of 30) showed grade A and 40% (12 of 30) showed grade B structural integrity. An obvious remnant-to-graft interval could be detected through the whole length of the graft. Tensile tests showed that the ultimate failure loads of the grafted tendons were similar between the groups (P = .365). In addition, there were no significant differences in the number of vascular endothelial growth factor-positive vessels and neurofilament-positive mechanoreceptors at either the femoral (P = .887 and P = .578, respectively), midsubstance (P = .063 and P = .546, respectively), or tibial (P = .193 and P = .978, respectively) level within the grafted tendons between the groups. CONCLUSIONS: The acute remnant-repairing ACLR in our rabbit femoral ACL detachment model showed no biomechanical and biological advantages compared with conventional ACLR. The acutely repaired ACL remnants presented a high proportion of poor structural integrity and low remnant-to-graft healing capacity. CLINICAL RELEVANCE: During our clinical practice, conventional ACLR may still not be replaced by remnant-repairing ACLR for the treatment of acute complete ACL tears.

Bone Contusions After Acute Noncontact Anterior Cruciate Ligament Injury Are Associated With Knee Joint Laxity, Concomitant Meniscal Lesions, and Anterolateral Ligament Abnormality.

PURPOSE: To examine the associated findings with bone contusions in patients after acute noncontact anterior cruciate ligament (ACL) injuries. METHODS: From January 1, 2011, to December 31, 2013, patients who underwent ACL reconstructions performed by the senior author (H.F.) were retrospectively analyzed. Presence and severity of bone contusion were determined from preoperative magnetic resonance images (MRIs) for each anatomic site including the lateral femoral condyle (LFC), lateral tibial plateau (LTP), medial femoral condyle (MFC), and medial tibial plateau (MTP). Multivariable logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associated findings (demographic data, preoperative physical examinations, concomitant meniscal lesions, intra-articular cartilage damages, and anterolateral ligament [ALL] abnormality) with bone contusions. Outcomes included the presence of bone contusions at each anatomic site (LFC, LTP, MFC, and MTP) and severity of lateral bone contusions (moderate/severe vs none/minimal). RESULTS: Among the 697 consecutive cases, 193 were finally selected. Prevalence of bone contusions seen on MRI was as follows: 60.6% LFC, 73.1% LTP, 6.2% MFC, and 21.2% MTP. Presence of bone contusions at LFC and LTP were significantly associated with high-grade (grade II and III) pivot-shift (ORLFC, 7.39; 95% CI, 1.99, 27.44; ORLTP, 2.52; 95% CI, 1.02, 6.24), concomitant lateral meniscal lesions (ORLFC, 3.23; 95% CI, 1.93, 11.31; ORLTP, 10.17; 95% CI, 1.86, 55.47), and ALL abnormality (ORLFC, 3.79; 95% CI, 1.46, 9.84; ORLTP, 4.47; 95% CI, 1.28, 15.58). However, none of the above associated findings was correlated with the presence of bone contusions at MFC and MTP. Furthermore, moderate/severe lateral bone contusions were still found to be significantly associated with high-grade (grade II and III) pivot-shift (ORLFC, 14.89; 95% CI, 2.71, 82.11; ORLTP, 6.76; 95% CI, 1.27, 36.06), concomitant lateral meniscal lesions (ORLFC, 17.34; 95% CI, 3.91, 76.87; ORLTP, 22.01; 95% CI, 5.08, 95.42), and ALL abnormality (ORLFC, 4.02; 95% CI, 1.33, 12.09; ORLTP, 2.57; 95% CI, 1.09, 6.04). CONCLUSIONS: For acute noncontact ACL injury, both the presence and the severity of lateral bone contusions are associated with high-grade (grade II and III) pivot-shift, concomitant lateral meniscal lesions, and ALL abnormality. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Prevalence of Lateral Meniscal Extrusion for Posterior Lateral Meniscal Root Lesion With and Without Concomitant Midbody Radial Tear in Anterior Cruciate Ligament Injury.

PURPOSE: To investigate the prevalence of lateral meniscal extrusion for patients with posterior lateral meniscal root lesions (PLMRLs) and for those with concomitant midbody radial tears (MRTs) in anterior cruciate ligament (ACL) injuries. METHODS: A database of consecutive patients undergoing primary ACL reconstruction between 2011 and 2013 was retrospectively reviewed to identify patients with isolated ACL injuries and those with associated PLMRLs. Patients with (1) unavailable preoperative magnetic resonance imaging scans, (2) other concomitant ligamentous injuries, (3) severe degeneration or malalignment, (4) infection or tumor, or (5) history of surgery on the injured side were excluded. For patients with associated PLMRLs (study group), degree of concomitant MRTs and status of meniscofemoral ligaments (MFLs) were verified arthroscopically. Prevalence of lateral meniscal extrusion was compared between (1) patients in the study group and those with isolated ACL injuries and between (2) those with and without concomitant MRTs in the study group. RESULTS: Of the 1,021 consecutive patients, 412 met the inclusion and exclusion criteria. Of those, 52 (5.1%) had an associated PLMRL (study group) and another 52 were randomly chosen from the 360 isolated ACL injuries as the control group. In the study group, 33 (63.5%) were arthroscopically verified to have concomitant MRTs. Prevalence of lateral meniscal extrusion was significantly higher (P < .0001) in the study group (30.8%; 95% confidence interval [CI], 18.3 to 43.3) than in the control group (1.9%; 95% CI, -1.8 to 5.6), whereas there was no significant difference (P = .758) between patients with (33.3%; 95% CI, 17.3 to 49.3) and without (26.3%; 95% CI, 6.5 to 46.1) concomitant MRTs in the study group. However, the 7 patients who showed either complete concomitant MRTs or absence of MFLs were all diagnosed to have lateral meniscal extrusion. CONCLUSIONS: The PLMRLs, identified in 5.1% of ACL injuries, appeared to result in lateral meniscal extrusion. Although the presence of a concomitant MRT did not further increase the prevalence of lateral meniscal extrusion in the setting of a PLMRL, surgical repair might still be necessary if a complete concomitant MRT or an absence of MFL was identified to restore normal meniscal functions. LEVEL OF EVIDENCE: Level III, prognostic case-control study.

Iatrogenic medial patellar instability following lateral retinacular release of the knee joint.

PURPOSE: Iatrogenic medial patellar instability (IMPI) is a disabling but easily missed condition that is most often seen as a late complication of lateral retinacular release (LRR) procedures. The purposes of this study were (1) to summarize the available diagnostic methods and (2) to explore the contributing factors of IMPI following LRR procedures. METHODS: The MEDLINE, PubMed, EMBASE and Cochrane Library databases were searched for studies including diagnosed IMPI cases following LRR procedures. All patients were first divided into IMPI group and non-IMPI group based on the diagnostic methods of IMPI collected from studies. Univariate analysis was performed by comparing the two groups with regard to individual patient data (age at initial LRR, gender) and surgical details (type, releasing scope, combined surgeries and indication) of LRR procedures. Multivariate logistic regression was carried out to identify independent contributing factors for IMPI and to calculate odds ratios (ORs). RESULTS: Eight studies with 274 patients (300 knees) were finally included. Of those, 161 patients (171 knees, 57.0 %) had IMPI and 113 patients (129 knees, 43.0 %) had no IMPI. Univariate analysis revealed a statistically significant difference between both groups for releasing scope (P 1 < 0.001) and indication of LRR procedures (P 2 < 0.001), with releasing lateral retinaculum (LR) + vastus lateralis (VL) tendon and absence of tight LR during the initial LRR procedures being more common in patients with IMPI. The independent contributing factors for IMPI identified in the multivariate logistic regression analysis were releasing LR + VL (OR1 = 16.49) and absence of tight LR (OR2 = 14.37). CONCLUSIONS: The IMPI was more common in patient with an over-released LRR and patient who was absent of tight LR during the initial LRR procedures. Aggressive surgical corrections and inappropriate indications of initial LRR were two contributing factors for the late complications of IMPI. This study suggests that the IMPI may occur as a major complication of LRR, especially when the VL tendon is extensively released or when there is no confirmative clinical evidence of a tight LR preoperatively. LEVEL OF EVIDENCE: IV.

Clinical outcome of simultaneous high tibial osteotomy and anterior cruciate ligament reconstruction for medial compartment osteoarthritis in young patients with anterior cruciate ligament-deficient knees: a systematic review.

PURPOSE: High tibial osteotomy (HTO) has been a well-established procedure addressing tibiofemoral osteoarthritis in young patients. However, for physically active patients with concomitant anterior cruciate ligament (ACL) injury, simultaneous HTO and ACL reconstruction is considered a salvage procedure. Controversy exists regarding the subjective and objective evaluations and the prevalence of complications. METHODS: A search in the Medline database and of major orthopaedic journals was performed. Articles were included if they met the specific inclusion and exclusion criteria. Anterior knee laxity, osteoarthritis, subjective outcomes, sagittal and coronal alignment, and complications were analyzed. RESULTS: A total of 721 articles were retrieved from the search, and 11 eligible studies (218 knees) were included for evaluation. Postoperatively, the mean side-to-side difference measured by KT-1000 (MEDmetric, San Diego, CA) was 2.4 mm, and 85.7% of patients gained grade A or B stability according to International Knee Documentation Committee evaluation. Medial compartment osteoarthritis showed a tendency of alleviation. Regardless of the scoring system, all subjective evaluations showed improvement and most of the participants returned to recreational sports. All cases of varus malalignment were corrected, with a mean value of 7.13°. The most prevalent complication was deep venous thrombosis (7.7%). CONCLUSIONS: Simultaneous HTO and ACL reconstruction was a salvage procedure for physically active young patients because it provided satisfactory restoration of anterior stability, alleviation of medial compartment osteoarthritis, improvement of subjective evaluations, and a predictable return to recreational sports. LEVEL OF EVIDENCE: Level IV, systematic review of Level III and IV studies.

Anatomical popliteofibular ligament reconstruction of the knee joints: an all-arthroscopic technique.

Injuries to the posterolateral corner of the knee present with variable injury patterns that have produced a number of reconstructive procedures in the literature. The present paper describes an all-arthroscopic technique that anatomically reconstructs the popliteofibular ligament (PFL) using either a semitendinosus autograft or an anterior tibialis allograft. During the surgery, the fibular insertion site as well as the distal portion of PFL is feasible to be identified under arthroscopy without any additional skin incision. Level of evidence V.

Is PLC repair of a peel-off femoral lesion an effective option in a multiligament setting?

PURPOSE: Treatment of posterolateral corner (PLC) injury in the multiligament-injured knee is still controversial. The aim of this study was to investigate the clinical outcome of acute or sub-acute surgical repair of Type 1 and 2 PLC peel-off lesions in a multiligament setting. METHODS: Mini-open direct repair of the PLC was performed in 13 patients. Combined PCL, ACL and MCL injuries were simultaneously managed. Telos valgus and varus stress radiographs at 30° of flexion with 150 N load were used to investigate medial and lateral joint opening. Posterior stress radiograph with 150 N load was used to investigate the function of the PCL. External rotational laxity was assessed with a dial test at 30° of knee flexion, and photographs were taken to measure angles. Anterior displacement was examined using the manual maximum test performed with a KT-1000 arthrometer. RESULTS: A statistically significant reduction between pre- and postoperative laxity values was achieved for every test. Particularly, lateral joint opening side-to-side difference reduced from 10.3 ± 4.0 to 1.0 ± 3.2 mm and external rotation reduced from 15 ± 8° to 0° ± 6° more than that of the contralateral uninjured knee. The medial joint opening side-to-side difference reduced from 11.5 ± 5.6 to 2.6 ± 2.7 mm in the 7 patients surgically managed for MCL lesion. The anterior tibial displacement side-to-side difference reduced from 14.0 ± 5.0 to 3.0 ± 5.0 mm in the 9 patients surgically managed for ACL lesion. The posterior tibial translation side-to-side difference reduced from 11.1 ± 5.1 to 4.4 ± 3.9 mm in the 11 patients treated for PCL lesion. CONCLUSION: The main finding of the current study is that acute repair of Type 1 and 2 PLC peel-off injury proved to be an effective procedure to restore PLC function in a multiligament-injured knee. These data enabled the current literature with an effective treatment option to face such a complex and various scenarios such as multiligament-injured knee. LEVEL OF EVIDENCE: IV.