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.

Effect of Anterolateral Ligament Status and Inherent Knee Anatomy on Anterior Tibial Subluxation of the Lateral Compartment After Acute Anterior Cruciate Ligament Injury: A Cohort Study Based on MRI Analysis.

BACKGROUND: Anterior tibial subluxation (ATS) of the lateral compartment entails a pathological tibiofemoral alignment in knees with anterior cruciate ligament (ACL) injury. Causes of increased ATS after an acute ACL injury are not clear, but soft tissue abnormalities and bony variations of the knee are potential causes. PURPOSE: To determine whether increased ATS of the lateral compartment in knees with acute ACL injury is associated with (1) anterolateral ligament (ALL) status and (2) inherent anatomy of the lateral femoral condyle (LFC) and lateral tibial plateau (LTP). STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 337 patients with clinically diagnosed ACL injuries treated between September 2019 and August 2021 were retrospectively reviewed, and 119 patients with acute ACL injury were included. Of them, 79 patients with impaired ALL (ALL injury group) and 40 patients with intact ALL (ALL intact group) were identified based on magnetic resonance imaging (MRI). The ATS of the lateral compartment measured on MRI was compared between the 2 groups. The bony anatomy of knees, quantified by the LFC length, LFC height, LTP length, and LTP slope, was also evaluated on MRI and correlated with the ATS with partial correlation coefficients. Multivariate linear regression was used to identify the independent predictors of increased ATS. RESULTS: The ATS of the lateral compartment in the ALL injury group was significantly larger than that in the ALL intact group (6.3 mm vs 4.0 mm, respectively; P = .001). In all included patients, the presence of ALL injuries independently predicted a mean increase in ATS of 1.8 mm (P = .003). In the ALL injury group, ATS was significantly correlated with LFC length (r = 0.463; P < .001), LFC height (r = -0.415; P < .001), and LTP slope (r = 0.453; P < .001); further, a 1-mm increase in LFC length, 1-mm decrease in LFC height, and 1° increase in LTP slope independently predicted a mean increase in ATS of 0.7 mm (P < .001), 0.6 mm (P < .001), and 0.5 mm (P < .001), respectively. In the ALL intact group, there was no significant correlation between ATS and any bony parameter. CONCLUSION: An impaired ALL increased the ATS of the lateral compartment after acute ACL injuries. In patients with combined ALL injuries, a flatter LFC and a steeper LTP in the sagittal plane were predictors of a further increase in ATS.

Clinical and Second-look Arthroscopic Results for Derotational Distal Femoral Osteotomy With Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocation With Increased Femoral Anteversion: A Series of 102 Cases With a Minimum Clinical Follow-up of 2 Years.

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.

Predictors of Graft Failure After Primary Medial Patellofemoral Ligament Reconstruction.

Background: The tibiofemoral rotation angle has been found to be higher in patients with recurrent patellar dislocations (RPDs) than in healthy people; however, little is known about the clinical significance of this finding. Purpose: To determine whether an increased tibiofemoral rotation angle is associated with graft failure after primary medial patellofemoral ligament reconstruction (MPFL-R) and to investigate the role of the tibiofemoral rotation angle in predicting MPFL-R failure in patients with RPDs. Study Design: Case-control study; Level of evidence, 3. Methods: We retrospectively analyzed the records of 632 consecutive patients with clinically diagnosed RPDs from 2011 to 2018. Postoperative stress radiography of the patellofemoral joint was performed to identify whether the graft failed. After a review, 33 patients who showed MPFL-R failure were allocated to the failure group. They were matched 1:2 to 66 participants who underwent successful MPFL-R (control group). The cutoff value and area under the curve (AUC) of the tibiofemoral rotation angle for predicting graft failure after primary MPFL-R were determined, and the risk factors for MPFL-R failure were assessed by multivariate logistic regression analysis. Results: The tibiofemoral rotation angle was significantly higher in the failure group than in the control group (16.4° ± 5.6° vs 6.4° ± 4.5°, respectively; P < .001). The cutoff value of the tibiofemoral rotation angle for predicting graft failure was 12.3° (sensitivity, 81.8%; specificity, 89.4%; AUC, 0.920). Overall, 3 risk factors for MPFL-R failure were determined: excessive tibiofemoral rotation (≥12.3°) (odds ratio [OR], 13.159 [95% CI, 2.469-70.139]; P = .003), a preoperative high-grade J-sign (OR, 7.674 [95% CI, 1.232-47.809]; P = .029), and a femoral tunnel malposition (OR, 6.976 [95% CI, 1.077-45.187]; P = .042). Conclusion: In this study, excessive tibiofemoral rotation, a preoperative high-grade J-sign, and a femoral tunnel malposition were identified as risk factors for graft failure after primary MPFL-R in patients with RPDs. More importantly, excessive tibiofemoral rotation ( ≥ 12.3°) may predict the failure of primary MPFL-R, which can help surgeons easily identify high-risk patients of MPFL-R failure before surgery.

The Increased Tibiofemoral Rotation: A Potential Contributing Factor for Patellar Maltracking in Patients with Recurrent Patellar Dislocation.

OBJECTIVE: The purpose of this study was to analyze the relationship between tibiofemoral rotation and patellar maltracking in patients with recurrent patellar dislocation. METHODS: A total of 143 consecutive knees (118 patients) with clinically diagnosed recurrent patellar dislocation from January 2018 to December 2019 were retrospectively analyzed. Patellar tilt angle and bisect offset index were recorded on axial CT to assesses the severity of patellar maltracking. Tibiofemoral rotation angle is measured by comparing the angle between the posterior femoral and tibial condylar lines on three-dimensional CT. The Pearson correlation was calculated to investigate the association between tibiofemoral rotation angle and patellar maltracking. Patients were divided into the rotation group (≥15°) and control group (<15°) based on the value of tibiofemoral rotation and a further comparison was performed. To further clarify the complicated relationship among tibial tubercle-trochlear groove (TT-TG), tibial tubercle-posterior cruciate ligament distance (TT-PCL), tibiofemoral rotation, and patellar maltracking, patients were divided into four subgroups according to the value of TT-TG and TT-PCL. RESULTS: The mean preoperative tibiofemoral rotation angle was 12° ± 6° (range, 0°-31°). Pearson correlation between patellar maltracking parameters (bisect offset index, patellar tilt angle) and various bony deformities found that the tibiofemoral rotation angle was moderately correlated with bisect offset index (r = 0.451, p < 0.001) and patellar tilt angle (r = 0.462, p < 0.001). Further results demonstrated that bisect offset index (152.1 vs 121.2, p < 0.001) and patellar tilt angle (41.2° vs 33.5°, p < 0.001) were significantly higher in the rotation group than that in control group. For patients with a TT-TG distance of >20 mm, the increased TT-TG distance was mainly caused by tibiofemoral rotation angle in group C (TT-TG > 20 mm, TT-PCL < 24 mm) and predominantly induced by tibial tubercle lateralization in group D (TT-TG > 20 mm, TT-PCL > 24 mm). Bisect offset index and patellar tilt angle were significantly higher in the group C than group D. CONCLUSION: The increased tibiofemoral rotation angle is associated with patellar maltracking in patients with recurrent patellar dislocation. Patients with increased tibiofemoral rotation angle usually have more severe patellar maltracking.

Biological enhancement methods may be a viable option for ACL arthroscopic primary repair - A systematic review.

BACKGROUND: Bioactive factors combined with advanced anterior cruciate ligament (ACL) primary repair technology have been used to treat ACL repairs. The current review was conducted to identify whether biological enhancement could enable superior clinical outcome, including side-to-side difference, failure rate, reoperation rate and subjective scores. HYPOTHESIS: The implementation of ACL primary repair with biological enhancement will provide better clinical outcomes in terms of side-to-side differences, failure rate, reoperation rate and subjective scores than ACL primary repair alone. MATERIALS AND METHODS: A systematic literature review was performed following PRISMA guidelines by searching all studies reporting outcomes of arthroscopic primary repair with or without biological augmentation published until April 19, 2020, in Medline, PubMed, Embase and the Cochrane Library. Primary metrics were side-to-side differences, failure rate and reoperation rate, as well as measurements of patient-reported outcomes at the last follow-up. RESULTS: A total of 20 studies were finally included in this work, of which 3 were Grade I (15%), 3 studies were Grade III (15%), and 14 studies were Grade IV (70%) in terms of the level of evidence. There were 729 patients with a mean age of 30 (range: 8-68) years, and the mean follow-up period of which was 38 (range: 3-122) months. At the final follow-up, the postoperative side-to-side differences (the proportion of patients with a side-to-side difference less than 3mm) and patient-report outcomes were significantly better in the biological enhancement group. Nevertheless, there were no significant differences between the two groups in the rate of surgical failure, the rate of revision, or the positive Lachman test or pivot shift test. CONCLUSION: Biologically enhanced arthroscopic ACL primary repair was superior to ACL primary repair alone in terms of postoperative side-to-side differences (proportion of patients with a side-to-side difference less than 3mm) and patient-reported outcomes. Thus, biologically enhanced arthroscopic ACL primary repair can be preferentially recommended over ACL arthroscopic primary repair alone. LEVEL OF EVIDENCE: IV, systematic review.

[Anatomical posterolateral complex reconstruction in treating severe posterolateral knee instability using Y-shaped allogeneic Achilles tendon].

OBJECTIVE: To investigate the surgical technique and effectiveness of anatomical posterolateral complex (PLC) reconstruction in treating severe posterolateral knee instability using Y-shaped allogeneic Achilles tendon. METHODS: The clinical data of 12 patients with Fanelli type C chronic PLC injury with severe posterolateral knee instability who met the selection criteria between June 2013 and August 2017 were retrospectively analyzed. There were 9 males and 3 females, with a median age of 34.5 years (range, 18-57 years). The average time from injury to surgery was 10.5 months (range, 3-24 months). All of them were multi-ligament injuries and were treated with anatomical reconstruction of Y-shaped allogeneic Achilles tendon. The posterior and varus stress X-ray films were used to measure and calculate the difference of posterior displacement of tibia and difference of lateral joint opening distance between bilateral knees to evaluate the backward stability of LCL and knee joint; the knee flexion 30° tibial external rotation test was used to calculate the difference of tibial external rotation angle between bilateral knees to evaluate the stability of knee external rotation. The knee function was evaluated by the International Knee Documentation Committee (IKDC) 2000 subjective and objective scores. RESULTS: The operation successfully completed in 12 patients, and there was no vascular and nerve injury during operation. The operation time was 2.5-3.5 hours, with an average of 2.7 hours; the intraoperative blood loss was 20-100 mL, with an average of 55 mL. All patients were followed up 13-41 months, with an average of 28.1 months. At last follow-up, the difference of posterior displacement of tibia, the difference of lateral joint opening, the difference of tibial external rotation angle between bilateral knees, and the IKDC2000 subjective score, the objective scores of tibial external rotation and knee varus significantly improved when compared with those before operation ( P<0.05). The knee joint of 1 patient with anterior cruciate ligament, posterior cruciate ligament, and PLC reconstruction was stiff at 15 months after operation, and the range of motion of the knee joint was 10°-80°. After arthroscopic release, the range of motion of the knee joint was 5°-120°, the reconstructed ligament was stable. In the other patients, the knee flexion angle was normal in 2 cases; 9 cases had knee flexion limitation of 5°-10°, with an average of 6.4°; no knee extension was limited. CONCLUSION: Anatomical PLC reconstruction using Y-shaped allogeneic Achilles tendon can effectively treat Fanelli type C chronic PLC injury with severe posterolateral knee instability and improve the knee joint stability.

Suture tape augmentation, a novel application of synthetic materials in anterior cruciate ligament reconstruction: A systematic review.

Objective: Suture tape (ST) is a common synthetic material in the repairing surgery of soft tissue. Recently, ST augmentation (STA) technique has been described as a novel way to improve the mechanical property of grafts in the anterior cruciate ligament (ACL) reconstruction (ACLR). However, the clinical outcomes of ACLR using ST-augmented grafts have not been clarified. This systematic review aimed to summarize the specific technique of STA and evaluate the clinical outcomes after ACLR with STA. Methods: A electronic search of PubMed and Embase databases with a manual search of Google Scholar was performed to identify studies that reported the clinical outcomes of ACLR with STA. Each included study was abstracted regarding the study features, patient data, surgical information, and outcome measures. Results: Nine studies were included, representing 314 knees in 314 patients undergoing ACLR with STA. Technically, ST was fixed independently from grafts in six studies and along with grafts in two studies. Most studies applied an equal or slightly less tension on ST than ACL graft. Clinically, significant improvements were found in the Lysholm, IKDC, and KOOS scores after a mean follow-up of 16.7 months. Physical examinations of 220 patients showed significant restoration of knee stability at the final follow-up. 59 of 80 (73.8%) patients returned to preinjury sports level at a minimum 2 year follow-up. Six of 266 (2.3%) patients had a graft failure during the first 2 years postoperatively. The use of ST was significantly associated with better Tegner scores and a trend toward significantly higher rates of return to sport compared to standard ACLR. No significant difference was found in most subjective scores, knee laxity, and graft failures between ACLR with or without STA. Conclusion: ACLR with STA achieved overall favorable clinical outcomes. Patients using ST-augmented grafts were seemingly associated with better sports performance compared to standard ACLR. But ACLR with STA was not superior to ACLR alone in most functional scores, knee stability measures, and graft failure rates. A tension equal to or slightly less than the ACL graft should be carefully applied on ST during fixation to avoid stress shielding of the graft.

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 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 Femoral Osteotomy for Treating Recurrent Patellar Dislocation in the Presence of Increased Femoral Anteversion: A Systematic Review.

BACKGROUND: Studies on the clinical outcomes of derotational femoral osteotomy to treat recurrent patellar dislocation in the presence of increased femoral anteversion are limited. PURPOSE: To investigate the role of derotational femoral osteotomy in the treatment of recurrent patellar dislocation in the presence of increased femoral anteversion. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: A systematic review was performed according to the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses) by searching the Medline, Embase, Web of Science, and Cochrane Library databases through February 10, 2021. Included were studies of skeletally mature patients presenting with recurrent patellar dislocation and exhibiting increased femoral anteversion who subsequently underwent derotational femoral osteotomy. Methodological quality was assessed using the MINORS (Methodological Index for Nonrandomized Studies) score. The basic characteristics of each study were recorded and analyzed: characteristic information, radiological parameters, surgical techniques, patient-reported outcomes, and complications. RESULTS: A total of 6 studies with 163 patients (170 knees) were included. Sample sizes ranged from 7 to 66 patients, and the patients were predominantly women (range, 79%-100%). The mean age and follow-up ranges were 18 to 28 years and 16 to 44 months, respectively. The mean femoral anteversion decreased significantly from 34° preoperatively to 12° postoperatively. In studies reporting pre- and postoperative outcomes, significant improvements were found in the Lysholm score (from 24.8 to 44.1), Kujala score (from 15.8 to 41.9), International Knee Documentation Committee score (from 11.0 to 28.0), and visual analog scale for pain (from 2.0 to 3.7). All studies reported postoperative complications, giving an overall reported complication rate of 4.7%, but no redislocations occurred during the follow-up period. CONCLUSION: For recurrent patellar dislocation in the presence of increased femoral anteversion, combination treatment with derotational femoral osteotomy led to favorable clinical outcomes with a low redislocation rate. However, there was no consensus among researchers on the indications for derotational femoral osteotomy in the treatment of recurrent patellar dislocation.

Arthroscopic Treatment of Labral Tears in Patients with Borderline Developmental Dysplasia of the Hip: A Retrospective Study with Mean 5.8 Years Follow-Up.

OBJECTIVE: To retrospectively assess the mid-term clinical and radiological results of hip arthroscopic treatment of labral tears in patients with borderline developmental dysplasia of the hip (BDDH). METHODS: From January 2010 and December 2019, data were retrospectively reviewed for all patients who underwent arthroscopic surgery of the hip for the treatment of intra-articular abnormalities. Only the Patients who had borderline developmental dysplasia (BDDH) were included. All operations were performed by two senior surgeons, the arthroscopic treatment including labral repair, labral debridement, minimal acetabuloplasty, femoroplasty and capsular closure. The evaluation consisted of pain evaluation (visual analog scale [VAS]), the modified Harris hip score (MHHS), range of motion, the radiological evaluation of plain film and MRI analysis of the hip joint. The plain film evaluation included anteroposterior views of the pelvis to assess lateral center-edge angle (LCEA) and acetabular inclination (AI), frog-leg lateral views of the hip to assess α angle. RESULTS: There were 34 patients (36 hips) ultimately enrolled in this study. The follow-up duration of the patients were minimal 2 years (average, 69.2 months) postoperatively. The patient group included seven men and 27 women, the mean age at the time of surgery was 30.9 years. The mean BMI was 22.3 kg/m2 . From the pre-operative status to the final follow-up visit, mean mHHS score increased from 64.5 to 92.7, mean VAS score decreased from 6.8 to 1.3. All scores exhibited statistically significant differences (P < 0.001). The mean LCEA decreased from 22.9° to 22.7°, the mean AI decreased from 7.7° to 7.6°. Which all showed no significant differences compared with the final follow-up to the pre-operative status (P > 0.05). However, the mean α angle was significantly decreased from 48.3° to 40.1° (P < 0.001). We encountered no significant complications such as infection, deep venous thrombosis, fluid extravasation, or permanent nerve injury. One patient (2.94%) underwent revision periacetabular osteotomies (PAO) because of subluxation of the hip joint with permanent pain after 6 months failed conservative treatment. CONCLUSION: Arthroscopic treatment of labral tears in patients with BDDH may provide safe and durable favorable results at midterm follow-up. The best outcome could be expected in patients with labral repair and closure of the capsule with strict patient selection criteria.

Increased Posterior Tibial Slope Is Associated With Greater Risk of Graft Roof Impingement After Anatomic Anterior Cruciate Ligament Reconstruction.

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.

Clinical, Radiographic, and Arthroscopic Outcomes of Surgical Repair for Radial and Avulsed Lesions on the Lateral Meniscus Posterior Root During ACL Reconstruction: A Systematic Review.

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 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.

Medial Patellofemoral Ligament Reconstruction With or Without Derotational Distal Femoral Osteotomy in Treating Recurrent Patellar Dislocation With Increased Femoral Anteversion: A Retrospective Comparative Study.

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.

Slope-Reducing Tibial Osteotomy Combined With Primary Anterior Cruciate Ligament Reconstruction Produces Improved Knee Stability in Patients With Steep Posterior Tibial Slope, Excessive Anterior Tibial Subluxation in Extension, and Chronic Meniscal Posterior Horn Tears.

BACKGROUND: Steep posterior tibial slope (PTS; >13°), excessive anterior tibial subluxation (ATS) in extension (>10 mm), and meniscus posterior horn tears (MPHTs) have been identified to be associated with primary anterior cruciate ligament (ACL) reconstruction (ACLR) failure. Recent studies have reported that steep PTS is directly correlated with excessive ATS in extension and concomitant MPHTs, especially for those patients with chronic (>6 months) ACL deficiency. There is increasing biomechanical evidence that slope-reducing tibial osteotomy decreases ATS in extension and protects the ACL graft. HYPOTHESIS: Slope-reducing tibial osteotomy combined with primary ACLR is effective for producing improved knee stability in patients with steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months). STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between June 2016 and January 2018, 18 patients with ACL injuries who had steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months) underwent slope-reducing tibial osteotomy combined with primary ACLR. The PTS and anterior subluxation of the lateral and medial compartment (ASLC and ASMC) in extension before and after the index procedures were regarded as primary clinical outcomes. Moreover, Lysholm score, Tegner activity score, International Knee Documentation Committee (IKDC) objective grade, pivot-shift test, and KT-1000 side-to-side difference were evaluated preoperatively and at the minimum 2-year follow-up visit. RESULTS: The mean PTS was 18.5° (range, 17°-20°) preoperatively and 8.1° (range, 7°-9°) postoperatively (P < .01). The mean ASLC and ASMC in extension were 12.1 mm and 11.9 mm preoperatively, which reduced to 1.0 mm and 1.5 mm at the last follow-up visit (P < .05). In addition, all of the following showed significant improvements (pre- vs postoperatively): mean Lysholm score (46.5 vs 89.5; P < .05), mean Tegner activity score (5.7 vs 7.3; P < .05), IKDC objective grading results (18 grade D vs 14 grade A and 4 grade B; P < .05), pivot-shift tests (15 grade 2+ and 3 grade 3+ vs 18 grade 0; P < .01), and KT-1000 side-to-side difference (13.0 mm vs 1.6 mm; P < .01). Moreover, no graft reruptures were found at the final follow-up visit. CONCLUSION: In this study, slope-reducing tibial osteotomy combined with primary ACLR effectively improved knee stability in patients with steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months).

Preoperative Complete Patellofemoral Dislocation in Extension Predicts an Inferior Clinical Outcome After Medial Patellofemoral Ligament Reconstruction in Patients With Recurrent Patellar Dislocation.

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.

Steep Posterior Tibial Slope and Excessive Anterior Tibial Translation Are Predictive Risk Factors of Primary Anterior Cruciate Ligament Reconstruction Failure: A Case-Control Study With Prospectively Collected Data.

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.