Medial Patellofemoral Ligament Reconstruction Group Research Articles

Medial Patellofemoral Complex Reconstruction (Combined Reconstruction of Medial Patellofemoral Ligament and Medial Quadriceps Tendon–Femoral Ligament) With Semitendinosus Autograft Resulted in Similar Clinical and Radiographic Outcomes to Medial Patellofemoral Ligament Reconstruction in Treating Recurrent Patellar Dislocation

PurposeTo compare clinical and radiographic outcomes of medial patellofemoral ligament reconstruction (MPFL-R) and medial patellofemoral complex reconstruction (MPFC-R) for recurrent patellar dislocation. Outcome measures were compared based on the Insall–Salvati index. MethodsPatients who were diagnosed with recurrent patellar dislocation and underwent either MPFL-R or MPFC-R (combined reconstruction of MPFL and medial quadriceps tendon-femoral ligament) were retrospectively analyzed. Group allocation was based on surgical procedure and patient characteristics were collected. Clinical assessments included patient-reported outcome measures (PROMs) and return-to-sports rates. Minimal clinically important difference analysis was performed. A subgroup analysis of PROMs was carried out between patients with an Insall–Salvati index ≤1.2 versus >1.2. The patellar tilt angle, lateral patellar displacement, and bisect offset ratio were measured pre- and postsurgery. Functional failures and complications were assessed. ResultsOverall, 70 patients (72 knees) in the MPFL-R group and 58 patients (61 knees) in the MPFC-R group were included. Patient characteristics were comparable between the groups. At a minimum follow-up of 24 (mean, 50.6 ± 22.1) months, all PROMs were substantially improved (P < .001), without significant intergroup differences. The percentages of patients reaching the minimal clinically important difference were similar after MPFL-R and MPFC-R: 98.6% versus 93.4% (International Knee Documentation Committee), 97.2% versus 98.4% (Lysholm), 98.6% versus 100% (Kujala), and 77.8% versus 72.1% (Tegner). The subgroup analysis based on patellar height and the return-to-sport rates also suggested comparable results. Radiographic evaluation demonstrated significantly smaller lateral patellar displacements (P = .004) and bisect offset ratios (P < .001) but similar patellar tilt angles after MPFC-R. Four (5.6%) patients receiving MPFL-R and 2 (3.3%) patients receiving MPFC-R reported recurrence of functional instability, without statistically significant difference. ConclusionsMPFC-R resulted in similar overall clinical and radiographic outcomes to MPFL-R in treating recurrent patellar dislocation. MPFC-R might not provide additional benefits for patients with an Insall-Salvati index >1.2. Level of EvidenceLevel IV, therapeutic, retrospective cohort study.

Results of Medial Patellofemoral Ligament Reconstruction with and without Tibial Tubercle Transfer in Patellar Instability: A Systematic Review and Meta-Analysis.

The optimal surgical intervention for lateral patellar instability remains a topic of controversy despite satisfactory clinical outcomes and low re-dislocation rates reported in numerous studies following medial patellofemoral ligament reconstruction (MPFLR) with and without tibial tubercle transfer (TTT). The purpose of this systematic review and meta-analysis is to investigate the hypothesis that combining MPFLR with TTT provides reduced complication rates and improved clinical outcomes to isolated MPFLR in patients with lateral patellar instability. We conducted a comprehensive systematic review and meta-analysis of comparative trials involving MPFLR with and without TTT, sourcing data from PubMed, the Cochrane Library, Embase, and Web of Science. The primary clinical outcomes analyzed included the Kujala score, the Lysholm score, complication rates, and the Caton-Deschamps index (CDI). Random or fixed effects were used for the meta-analysis. Postoperatively, there were no significant differences observed in the Kujala and Lysholm scores between MPFLR and MPFLR + TTT (p = 0.053). At the final follow-up, the CDI had decreased 0.015 (95% CI -0.044, 0.013; p = 0.289) points in the MPFLR group, with no statistical significance. In contrast, the MPFLR + TTT group demonstrated a significant decrease of 0.207 (95% CI -0.240, -0.174; p = 0.000) points in CDI. Notably, the complication rate was higher in the MPFLR + TTT group compared to the MPFLR-only group (RR = 2.472; 95% CI 1.638, 3.731; p = 0.000). Both MPFLR and MPFLR + TTT procedures yield significant improvements in the Kujala and Lysholm scores. However, the MPFLR + TTT approach results in an apparent improvement in CDI and corrects patellar maltracking, particularly in cases involving high tibial tuberosity-trochlear groove (TT-TG) (>20 mm) or patella alta (CDI > 1.2), while MPFLR alone cannot. It is essential to consider the higher complication rate of MPFLR + TTT, which suggests that MPFLR alone may be sufficient for patients without high TT-TG or patella alta.

Concomitant Tibial Tubercle Osteotomy Reduces the Risk of Revision Surgery After Medial Patellofemoral Ligament Reconstruction for the Treatment of Patellar Instability

To compare postoperative complication rates between patients who underwent medial patellofemoral ligament reconstruction (MPFLR) and those who underwent MPFLR with tibial tubercle osteotomy (TTO) in a large-scale study. A secondary goal was to investigate demographic associations with outcomes. Patients who underwent MPFLR (n= 3,480) or MPFLR-TTO (n= 615) for patellar instability were identified in the PearlDiver database. Rates of surgery for infection, procedures for knee stiffness, patellar fracture, and revision MPFLR within 2 years postoperatively were compared using multivariable logistic regression. Demographic associations with outcomes were also investigated. The MPFLR-TTO cohort exhibited a significantly lower rate of revision surgery at 2 years (0.8% vs 1.9%; odds ratio [OR], 0.33; 95% confidence interval [CI], 0.10-0.80; P= .036) when compared with the MPFLR group. Independent of index procedure, patients younger than 21 years had significantly lower rates of requiring procedures for knee stiffness (OR, 0.35; 95% CI, 0.22-0.54; P < .001) and any complication at 2years (OR, 0.59; 95% CI, 0.45-0.78; P < .001) when compared with older patients. Male patients displayed a significantly lower rate of requiring procedures for knee stiffness at 2 years than female patients (OR, 0.46; 95% CI, 0.25-0.78; P= .007). Tobacco use was associated with a significantly higher rate of postoperative infection at 2 years (OR, 2.35; 95% CI, 1.00-5.38; P= .046). The MPFLR cohort exhibited higher rates of revision surgery at 2 years compared with the MPFLR-TTO cohort. Patient age under 21 years was associated with lower rates of any complication and requiring procedures for knee stiffness, male sex was associated with a lower rate of requiring procedures for knee stiffness, and tobacco use was associated with a higher rate of surgery for postoperative infection. This information can assist surgeons when counseling patients before these procedures are performed. Level III, retrospective, comparative prognostic trial.

Radiographic Changes After Medial Patellofemoral Ligament Reconstruction in Skeletally Immature Patients Compared With an Age- and Sex-Matched Cohort

Background: Despite recent evidence that medial patellofemoral ligament reconstruction (MPFLR) in the skeletally immature patient is both safe and effective, there are limited data evaluating postoperative coronal- and sagittal-plane growth and radiographic patellofemoral parameters in this population. Purpose: The primary purpose was to assess radiographic measures of coronal-plane alignment, longitudinal growth, patellar congruence, and trochlear dysplasia after MPFLR in a skeletally immature population. A secondary purpose was to assess this population compared with a matched cohort with a focus on trochlear dysplasia prevalence and the effect of MPFLR on patellar height. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 28 children with a minimum 1-year follow-up who underwent isolated MPFLR were identified. All patients were skeletally immature, defined as fully open physes on both sides of the knee joint, at the time of surgery. The development of a limb length discrepancy or angular growth abnormalities were assessed on standing hip-to-ankle radiographs, patellar tilt and congruence were measured on the Merchant view of the knee, and the grade of trochlear dysplasia and patellar height were assessed on lateral knee radiographs. A sex- and age-matched group of patients who underwent anterior cruciate ligament reconstruction was formed as a control for patellar height and trochlear dysplasia measurements. Results: The mean patient age was 11.71 ± 2.02 years at the time of surgery with a mean follow-up of 23.54 ± 12.49 months. All but 1 patient in the MPFLR group had preoperative features consistent with trochlear dysplasia. There was no significant difference in limb length or coronal-plane alignment at final follow-up (P = .725 and P > .999, respectively). Both the MPFLR and the anterior cruciate ligament reconstruction groups had a statistically significant decrease in the Caton-Deschamps index between the preoperative and postoperative time points (mean, 0.18 ± 0.20 and 0.11 ± 0.14, respectively; P = .161). Conclusion: MPFLR may be safely performed utilizing an epiphyseal femoral socket in a skeletally immature cohort without affecting normal longitudinal growth or coronal limb alignment. The previously reported effect of MPFLR in reducing patellar height may be related to physiological growth based on similar changes noted in a comparison cohort that did not undergo the procedure.

Medial patellofemoral ligament reconstruction combined with derotational distal femoral osteotomy yields better outcomes than isolated procedures in patellar dislocation with increased femoral anteversion.

The purpose of this study was to evaluate and compare clinical and radiological outcomes between isolated medial patellofemoral ligament reconstruction (MPFLR) and MPFLR combined with derotational distal femoral osteotomy (DDFO) for patellar dislocation with increased femoral anteversion (FA). Between 2014 and 2019, 36 patients who underwent isolated MPFLR and 31 patients who underwent MPFLR combined with DDFO were retrospectively included. Clinical outcomes included physical examinations, functional outcomes (Kujala, Lysholm, International Knee Documentation Committee (IKDC), and Banff Patella Instability Instrument (BPII) scores), activity level (Tegner activity score and return to sports), complications, and patellar re-dislocation rate. Radiological outcomes included patella tilt angle, patellar congruence angle, and patella-trochlear groove distance. All clinical outcomes improved significantly in both groups, but the DDFO group had significantly better postoperative scores than the MPFLR group (Kujala: 85.1 ± 7.7 vs. 80.5 ± 8.4, P = 0.023; Lysholm: 86.8 ± 8.2 vs. 81.9 ± 9.1, P = 0.026; IKDC: 86.2 ± 10.0 vs. 81.7 ± 8.1, P = 0.045; and BPII: 68.0 ± 12.5 vs. 62.3 ± 10.0, P = 0.039). Both groups achieved successful return to sports (90.3% vs. 91.7%). No re-dislocation or major complications occurred. Radiological outcomes improved significantly in both groups, but the DDFO group had better outcomes (P < 0.05). The tibial tubercle-trochlear groove distance was only improved after DDFO from 17.0 ± 2.3mm to 15.1 ± 2.0mm (P = 0.001). Both isolated MPFLR and MPFLR combined with DDFO yielded satisfactory clinical and radiological outcomes in the treatment of patellar dislocation with increased FA. However, combined DDFO had better outcomes and should be considered a priority. Level III.

Medial Patellofemoral Ligament Reconstruction is Preferred to Repair or Reefing for First-Time Patellar Dislocation: A Systematic Review and Meta-analysis.

The purpose of this systematic review aimed to investigate the clinical outcome of medial patellofemoral ligament (MPFL) reconstruction, MPFL repair and medial reefing for patients with first-time patellar dislocation. Databases of PubMed, EMBASE, Cochrane Library and Web of Science were searched up to May 8, 2022. Only articles treating first-time patellar dislocation with MPFL reconstruction, MPFL repair and medial reefing were included in the analysis. Eligible identification, data extraction, quality assessment and statistical analysis were performed by two independent reviewers. The primary outcome measures were the incidences of postoperatively redislocation and reoperation. The second outcomes were the Kujala functional score and complications (including infection, osteoarthritis, and loss of range of motion). Twenty-two studies involving 668 patients met the inclusion criteria. Of which, four studies involving 126 patients were in MPFL reconstruction group, ten studies involving 220 patients in MPFL repair group and 9 studies involving 322 patients in medial reefing group. Our results showed that the MPFL reconstruction (1.8%, 95% CI -0.5 to 4.0%) had a significantly lower rate of postoperative redislocation and reoperation rate than the MPFL repair (15.4%, 95% CI 5.2-25.7%) and medial reefing (18.0%, 95% CI 9.3-26.7%). Besides, no significant differences were found in the Kujala score and complication rate among the three treatments. The available evidence demonstrated that MPFL reconstruction could achieve significantly lower redislocation rate and reoperation rate than MPFL repair and medial reefing after first-time patella dislocation. Furthermore, there was not enough evidence to reveal that MPFL reconstruction provided better functional outcome compared with MPFL repair and medial reefing. MPFL reconstruction is a preferred surgical treatment for patients with first-time patellar dislocation. Level IV, systematic review of Level I-IV.

Isolated medial patellofemoral ligament reconstruction results in similar postoperative outcomes as medial patellofemoral ligament reconstruction and tibial-tubercle osteotomy: a systematic review and meta-analysis.

To determine the effect of isolated medial patellofemoral ligament reconstruction (MPFLR) versus concomitant MPFLR and tibial-tubercle osteotomy (TTO) on patient-reported functional outcomes, rate of patellar redislocation, and rate of return to sport in skeletally mature patients with recurrent patellar instability and lateralization as defined by elevated tibial-tubercle trochlear groove (TT-TG) distance. Three databases MEDLINE, PubMed and EMBASE were searched from inception to July 10th, 2022 for literature outlining the management of patients with TT-TG indices greater than 15mm with either isolated MPFLR or concomitant MPFLR and TTO procedures. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on functional outcomes via the Kujala anterior knee pain score, redislocation rates, return to sport rates, and complications were recorded. The MINORS score was used for all studies to perform a quality assessment of included studies. A total of 31 studies comprising 1405 patients (1452 knees) were included in this review. The mean Kujala score in 13 studies comprising 848 total patients in the isolated MPFLR group was 85.0 (range 80.9-97.5) compared to a score of 83.7 (range 77.2-94.0) in 14 studies comprising 459 patients in the concomitant group. The mean pooled redislocation rate in 19 studies examining isolated MPFLR procedures comprising 948 patients was 3.1% (95% CI 2.1-4.4%, I2 = 7%) as opposed to 3.2% (95% CI 1.9-5.0%, I2 = 0%) in 15 studies comprising 486 patients in the concomitant group. The mean pooled return to sport rate in seven studies with 472 total patients in the isolated MPFLR group was 82% (95% CI 78-86%, I2 = 16%) compared to a score of 92% (95% CI 78-99%, I2 = 58%) in four studies comprising 54 patients in the concomitant group. There were similar complication rates between both treatment groups, including range of motion deficits, fractures, infections, and graft failures. Isolated MPFLR leads to similar anterior knee pain, similar redislocation rates and lower return to sport rates than concomitant MPFLR and TTO procedures in patients with TT-TG distances greater than 15mm. Information from this review can aid surgeons in their decision to choose MPFLR versus concomitant procedures for this patient population, and can also guide future studies on this topic. Level IV.

Isolated Lateral Release is Inferior to Medial Patellofemoral Ligament Reconstruction for Surgical Management of Patella Instability in Pediatric Patients

Background:The optimal treatment for chronic patella instability remains controversial. Medial patellofemoral ligament reconstruction (MPFLR) has emerged as the “gold standard” for soft tissue stabilization. However, isolated lateral release (ILR) is still commonly performed to treat chronic patella instability despite growing evidence against this approach.Hypothesis/Purpose:Our purpose is to evaluate long-term revision rates and short-term post-operative complications in pediatric patients undergoing either MPFLR or ILR for recurrent patellar instability. The hypothesis is that MPFLR is a superior treatment option with reduced long term revision rates and comparable short-term complications.Methods:The MarketScan database was queried from 2007-2015 to identify patients who underwent MPFLR or ILR as their primary surgical treatment of their chronic patellar instability. Patients were excluded if they had incomplete records up to 5 years or if they underwent concomitant osteotomy or cartilage restoration during their index stabilization procedure. Baseline demographic data and patient co-morbidities were documented. Two and five year revision surgical stabilization rate and post-operative complications were reported. Results were analyzed statistically.Results:This study identified 471 patients (mean age 15.6 years, female 56.9%) who underwent MPFLR and 528 patients (mean age 15.5 years, female 70.5%) who underwent ILR for chronic patellar instability. Patients were stratified into two mutually exclusive groups: 1) MPFLR only or 2) ILR only. Patients who underwent MPFLR experienced higher rates of overall complications within 90 days of surgery (8.7% vs 4.9%, p = 0.0171). MPFLR had a higher rate of early wound complications (0.8% vs. 0%, p <.033) There was no difference in revision stabilization rate between MPFLR and ILR at 2 year follow-up. However, at 5 years of follow-up, 8.9% of patients who underwent ILR underwent revision surgery compared to 3.0% of patients who underwent MPFLR as their index surgery (p < 0.0001).Conclusions:Isolated lateral release is an inferior treatment option for surgical stabilization of chronic patella instability as compared to medial patellofemoral ligament reconstruction in pediatric patients. Despite slightly higher rate of short term complications in the MPFLR group and similar revision rates at 2 years, MPFLR has significantly decreased risk of revision stabilization at 5 year follow-up.Table 1.Postoperative Complications - within 90 daysTable 2.Quality Outcomes

A Prospective Cohort Study on Quality of Life among the Pediatric Population after Surgery for Recurrent Patellar Dislocation.

Patellofemoral instability is a frequent cause of knee pathology affecting quality of life among the pediatric population. Here, we present a prospective cohort study which included patients who had undergone surgical management using the lateral release and medial imbrication approach (LRMI) or medial patellofemoral ligament reconstruction (MPFL-R). The object of this study was to assess the quality of life among children that have undergone surgical treatment for patellar dislocation. Quality of life was assessed before and after surgery using the Pediatric International Knee Documentation Committee form (Pedi-IKDC), a questionnaire that aims to quantify knee functionality. Postoperative scarring was evaluated using The Stony Brook Scar Evaluation Scale. One hundred and eight patients were selected and grouped according to the type of procedure. Before surgery, the two groups had similar mean Pedi-IKDC scores (41,4 MPFL-R vs. 39,4 LRMI p = 0.314). Improvements were observed in the postoperative scores. The MPFL-R technique showed promising outcomes. When comparing the two surgical groups, there was a significant difference in favor of MPFL-R group (MPFL-R 77.71 points vs. LRMI 59.74 points, p < 0.0001–95% CI (11.22–24.72)). Using the Stony Brook Scar Evaluation Scale, a significant difference in scar quality in favor of MPFL-R was observed (4,5 MPFL-R vs. 2,77 LRMI p = 0.002). In conclusion, this study provides objective evidence-based outcome assessments that support the medial patellofemoral ligament reconstruction technique as the gold standard for patellofemoral instability.

ISOLATED MPFL RECONSTRUCTION VS. TIBIAL TUBERCLE OSTEOTOMY AND MEDIAL RETINACULAR PLICATION FOR RECURRENT PATELLAR INSTABILITY: A MATCHED, COHORT ANALYSIS OF CLINICAL OUTCOMES COMPARING TWO TECHNIQUES

Background:Historically, the most commonly utilized technique to address recurrent patellofemoral instability (PFI) was a combined proximal and distal realignment, specifically the tibial tubercle osteotomy (TTO) with a proximal medial retinacular plication/reefing/tightening/repair (MRP). Rising interest in the medial patellofemoral ligament reconstruction (MPFLR) over the last decade, now frequently performed as a more powerful isolated proximal realignment procedure, has prompted debate over the optimal technique to treat this common condition.Hypothesis/Purpose:The study hypothesis was that no difference would be detected in recurrent PFI rates or revision surgery rates between patients who underwent TTO-MRP vs. MPFLR.Methods:With cohorts derived from a large, single-center PFI database of 523 patients who underwent a variety of stabilization procedures, 114 eligible MPFLR patients were matched to 109 TTO patients based on age, gender, BMI, and TT-TG distance. Propensity score matching was conducted using logistic regression models to produce 1:1 matching, and a caliper of 0.2 standard deviations of the estimated propensity score was used to for the nearest neighbor matching algorithm. Final matching procedure resulted in 84 MPFLR patients and 84 TTO patients. These were compared on demographics and post-operative clinical results.Results:Demographic and radiologic comparisons of the cohorts are shown in Table 1, with the only difference between groups being an expected higher rate of patients with open physes in the MPFLR cohort. Table 2 shows the TTO-MRP group had longer follow up times, but comparable rates of return to sports. The MPFLR group had a higher rate of recurrent instability, but not to a significant degree, and a significantly higher incidence of revision patellar stabilization surgery (p<0.001). The TTO group had a higher rate of additional knee surgery, the majority of which were implant removal for TTO screws.Conclusion:The TTO-MRP shows equivalent or superior results to the MPFLR for treatment of PFI. However, implant removal may be common with TTO, though this may be somewhat technique-dependent. In the current landscape of increasing interest and utilization of MPFLR as an all-encompassing PFI surgery, the influence of distal bony realignment to minimize recurrence should not be underappreciated.Tables/Figures:

Functional outcomes of paediatric medial patellofemoral ligament (MPFL) reconstruction surgery with or without patella distalisation and medialisation for recurrent patella instability

BackgroundNo studies to date have compared the outcome of isolated medial patellofemoral ligament reconstruction (MPFLR) surgery with MPFLR plus re-alignment procedures (MPFLR+) in the paediatric population, making it unclear when additional re-alignment procedures are required.By retrospectively reviewing and comparing our MPFLR patient cohorts’ we aim to generate guidance to aid surgical planning. MethodsUniversity of Salford ethical approval was secured and theatre records were retrospectively reviewed, identifying all patients less than 18 years-of-age who received MPFLR surgery between October 01, 2015 and October 01, 2019.All patients were contacted for documented consent. Pre-operative and post-operative outcome questionnaires were reviewed in conjunction with patient’s medical records and radiological imaging. ResultsA total of 75 MPFLR surgeries were identified and 33 patients (40 knees) consented for inclusion in the study; 23 MPFLR and 17 MPFLR+. Mean improvement in outcome scores achieved statistical significance (P < 0.05) in almost all questionnaire subtypes for both groups. A greater improvement in Quality of life (QoL) correlated with an increased tibial tuberosity–trochlear groove distance (TT-TG) in the MPFLR group 0.557 (P = 0.025) and a lower Patellotrochlear index (PTI) - 0.549 (P = 0.034) in the MPFLR + group.Increased Body Mass Index (BMI) correlated with worse outcomes in numerous questionnaire subtypes (P = 0.05 and P = 0.01) for the MPFLR + group.Increased Trochlear dysplasia correlated – 0.541 (P = 0.03) with less improvement in symptoms following MPFLR + surgery and an increased need for revision surgery 0.312 (P = 0.053) in both groups. ConclusionsBoth groups achieved good outcomes and statistically significant improvements in almost all mean outcome scores following MPFLR surgery, suggesting that our current described selection criteria are appropriate. While we were unable to identify any absolute radiological cut off figures in this diverse population with changing anatomy, we recommend additional procedures be considered for high TT-TG distances and or significant patella alta.Patients with a high BMI should be supported in losing weight prior to surgery and patients with trochlear dysplasia need counselling with regard to potential lesser improvements in symptoms, a higher risk of failure and need for revision surgery. Additional realignment procedures did not appear to offer any improved outcome in the presence of trochlear dysplasia.Level of Evidence IV: Case series.

Comparison of MPFL Repair Versus MPFL Reconstruction for Refractory Patella Instability in Patients Under 18 Years Old

Background:The medial patellofemoral ligament (MPFL) is the primary soft-tissue restraint against lateral patellar displacement. Surgery to address MPFL incompetence is the current gold standard for recurrent patellofemoral instability. In the young patient, controversy remains regarding the role of MPFL repair in the setting of recurrent patella instability.Hypothesis/Purpose:Our purpose was to investigate subjective outcomes and complication profile of consecutive cohorts under age 18 undergoing MPFL repair or MPFL reconstruction. Our hypothesis was that the MPFL reconstruction group would have higher subjective outcome scores and a lower complication profile.Methods:Following IRB approval, a retrospective review of prospectively collected data identified a consecutive cohort of patients undergoing soft tissue stabilization for recurrent patella instability. Surgery was performed by a single sports fellowship trained surgeon between 2011-2019. MPFL repair was performed on patients prior to November 2015 and MPFL reconstruction with allograft from December 2015 to present. Patients undergoing concomitant bony realignment procedures were included. Patient reported outcomes (PROs) were collected including PROMIS, KOOS, IKDC, Marx, Tegner, and SANE scores. Complications requiring re-operation (i.e., infection, stiffness, recurrent instability) were recorded. Results were analyzed statistically.Results:The cohort was comprised of 43 patients (53 knees), with 15 males (34.9%), and 28 females (65.1%). The MPFL-Repair cohort had 22 patients (24 knees) and the MPFL-Reconstruction had 25 patients (29 knees). The average age of the MPFL-Repair cohort was 14.82 (range 10.5-17.8) and the average age of the MPFL-Reconstruction group was 15.59 (13.0-17.7). At final follow-up (minimum 6 months), there were no statistically significant differences between cohorts for KOOS Pain (p=0.4126), KOOS symptoms (p=0.7990), KOOS ADL (p=0.4398), KOOS Sport Rec (p=0.3357), KOOS QOL (p=0.8707), Global Physical Health (p=0.9736), Global Mental Health (p=0.1724), Physical Function (p=0.8077), Pain Interference (p=0.9740), Mobility T-Score (p=0.0634), Marx activity score (p=0.0844), Tegner Score (p=0.0752), IKDC (p=0.2646), and SANE score (p=0.0811). Regarding complications requiring re-operation, there was 1 knee in the MPFL-Reconstruction group (3.4%) that required further surgery (1 for fracture) and 9 knees in the MPFL-Iso cohort (37.5%) that required re-operation (1 for fracture, 8 for recurrent instability). The difference in complication rate was statistically significant (p=0.0012).Conclusion:In patients under 18 years old undergoing surgery for refractory patella instability, both MPFL allograft reconstruction and MPFL primary repair demonstrated no difference in subjective outcome scores at midterm follow-up. MPFL primary repair had significantly increased rate of complication requiring re-operation, particularly recurrent patella instability requiring revision to MPFL reconstruction.Tables/Figures:Table 1.1.KOOSSub-scaleSurgery Type>6 Months Post-opNP-valueMeanSD95% CILower BoundUpper BoundADLRepair89.4516.0782.3296.57220.4398Reconstruction92.529.0988.4996.5522PainRepair85.8515.8478.8392.88220.4126Reconstruction89.028.4285.2892.7522SportRepair66.5929.5453.5079.69220.3357Reconstruction73.6416.7066.2381.0422SymptomsRepair81.7316.3574.4888.98220.7990Reconstruction80.6411.3075.6385.6522QOLRepair60.8226.1049.2472.39220.8707Reconstruction61.9418.7953.6170.2722Table 1.2.PROMISSub-scaleSurgery Type>6 Months Post-opNP-valueMeanSD95% CILower BoundUpper BoundGlobal Physical HealthRepair50.3910.3744.4056.38140.9136Reconstruction50.097.1847.1952.9926Global Mental HealthRepair56.738.1152.0561.41140.1724Reconstruction52.2710.4048.0656.4726Pain Interference T-ScoreRepair52.279.6047.1557.38160.9740Reconstruction52.178.2248.8555.4926Physical FunctionT-ScoreRepair47.168.2442.7751.55160.8077Reconstruction47.787.9944.6250.9427MobilityT-TestRepair50.068.9843.1556.9690.0634Reconstruction43.317.1239.0147.6113Table 1.3.OtherVariableSurgery Type>6 Months Post-opNP-valueMeanSD95% CILower BoundUpper BoundMarxRepair7.106.124.249.96200.0844Reconstruction3.685.900.846.5319SANERepair62.7528.5547.5477.96160.0811Reconstruction75.5215.7868.7082.3523TegnerRepair5.213.033.756.67190.0752Reconstruction3.682.002.724.6519IKDCRepair70.0419.6259.5980.50160.2646Reconstruction63.7414.7057.2270.2622

Concomitant Medial Patellofemoral Ligament Reconstruction and Tibial Tubercle Osteotomy Do Not Increase the Incidence of 30-Day Complications: An Analysis of the NSQIP Database.

Background:Lateral patellar dislocations account for 2% to 3% of total knee injuries, especially in adolescents. Depending on the anatomic abnormality contributing to lateral patellar instability, medial patellofemoral ligament reconstruction (MPFLR) and/or tibial tubercle osteotomy (TTO) may be indicated.Purpose:To assess the risk of adverse events (AEs) after TTO, MPFLR, and concomitant MPFLR and TTO.Study Design:Cohort study; Level of evidence, 3.Methods:Patients who underwent MPFLR, TTO, and concomitant MPFLR and TTO between 2005 and 2016 were identified through the American College of Surgeons–National Surgical Quality Improvement Program (ACS-NSQIP) database. Medical complications (eg, surgical site infection and deep vein thrombosis), readmission rates, and extended hospital stay within 30 days of the procedure were recorded. Outcomes were compared with bivariate and multivariate Poisson regression.Results:Out of 882 patients, 617 (70.0%) underwent isolated MPFLR, 170 (19.3%) underwent TTO, and 95 (10.8%) underwent concomitant MPFLR and TTO. The operative time for concomitant MPFLR and TTO was significantly longer (122 ± 45 minutes) compared with isolated MPFLR (97 ± 55 minutes; P < .001) and isolated TTO (89 ± 51 minutes; P < .001). There were 32 AEs (3.6%), with 10 AEs in the isolated TTO group (5.9%), 18 AEs in the isolated MPFLR group (2.9%), and 4 AEs in the MPFLR + TTO group (4.2%). There was no significant difference in the rate of AEs between the isolated MPFLR and isolated TTO groups (P = .1), isolated MPFLR and MPFLR + TTO groups (P = .5), and isolated TTO and MPFLR + TTO groups (P = .8). Diabetes mellitus was associated with an increased risk of developing an AE (odds ratio, 4.0; P = .003), and hypertension resulted in an increased risk of an extended hospital stay (odds ratio, 4.0; P = .010).Conclusion:While concomitant MPFLR and TTO significantly increased operative time, there was no difference in the rate of AEs, extended hospital stay, and readmissions within 30 days after isolated MPFLR, isolated TTO, and concomitant MPFLR and TTO.

Biomechanical and Functional Outcomes After Medial Patellofemoral Ligament Reconstruction: A Pilot Study

Background:Previous studies have acknowledged the medial patellofemoral ligament (MPFL) as the primary stabilizer of the patella, preventing lateral displacement. MPFL reconstruction (MPFL-R) restores stability and functionality to the patellofemoral joint and has emerged as a preferred treatment option for recurrent lateral patellar instability.Purpose:To objectively measure biomechanical characteristics of athletes cleared for return to sport after MPFL-R compared with healthy controls.Study Design:Cohort study; Level of evidence, 3.Methods:A prospective case-control study design was employed on 31 total athletes. Sixteen athletes (6 male, 10 female; mean age, 16.1 ± 2.74 years; 385 ± 189 days after surgery and 235 ± 157 days after return to sport) underwent MPFL-R and were medically cleared to return to sport. This group was matched by age, sex, and activity level to 15 healthy athletes with no history of lower extremity injuries. Athletes and controls completed validated questionnaires as well as hopping, jumping, and cutting tests with 3-dimensional motion analysis and underwent strength, flexibility, laxity, and balance assessments.Results:Participants in the MPFL-R group scored significantly lower (worse) on the International Knee Documentation Committee (IKDC) (89.2 ± 7.6 vs 98.1 ± 2.0, respectively; P = .0005) and significantly higher (worse) on the Tampa Scale for Kinesiophobia (TSK) (32.4 ± 5.0 vs 25.4 ± 6.5, respectively; P = .006) than those in the control group, but there was no difference in the Kujala score (95.6 ± 5.3 vs 98.8 ± 3.0, respectively; P = .06). Participants in the MPFL-R group demonstrated reduced hip and ankle flexion relative to those in the control group (P < .05). Participants in the MPFL-R group also took significantly longer to complete the 6-m timed hop test relative to those in the control group (P < .05). No statistically significant differences were found in anthropometrics, knee extension or flexion strength, hamstring flexibility, hip abduction strength, or joint laxity between the MPFL-R and control groups.Conclusion:The current data indicate that MPFL-R generally restores functional symmetry, while subtle deficits in global power may remain after being released to full activity. Clinicians should ensure that athletes are fully rehabilitated before returning to sport after MPFL-R by emphasizing functional multijoint exercises.

Surgical treatment of patellar instability: clinical and radiological outcome after medial patellofemoral ligament reconstruction and tibial tuberosity medialisation.

The aim of this retrospective study was to analyse clinical and radiological outcome after medial patellofemoral ligament reconstruction (MPFLR) and tibial tuberosity medialisation (TTM) in patients with recurrent patellar instability. Thirty-five patients were included between 2008 and 2012. According to defined criteria such as tibial tuberosity-trochlear groove (TTTG) distance, hyperpression on the lateral patella facet and lateral retropatellar cartilage damage either MPFLR (group A) or TTM (group B) was performed: 18 patients underwent TTM, the other 17 patients underwent MPFLR. At a mean of 25.4±9.7 (group A) and 35.2±17.6months (group B) patients were clinically and radiologically reviewed. Validated knee scores such as Kujala, Lysholm and Tegner score were evaluated. In both groups one patient reported of a non-traumatic patellar redislocation. Patients who underwent MPFLR (group A) had less pain postoperatively during activity according to the Visual Analogue Scale (group A: 2.0±2.1 points, group B: 3.9±2.3 points). Retropatellar cartilage damage increased in group B from grade 1 (range: 1-3) preoperatively to grade 2 (range 1-3) postoperatively (p>0.05). All other clinically evaluated items, as well as the applied knee scoring systems, indicated no significant difference (p>0.05) and displayed good to excellent results. MPFLR and TTM leed to good clinical results despite its own indications. For this reason-in selected cases-TTM may still be a suitable procedure for surgical treatment of patellar instability. However, patients treated by TTM (group B) revealed an increased retropatellar cartilage damage as well as significantly more pain during activity.

Effect of Trochlear Dysplasia on Outcomes After Isolated Soft Tissue Stabilization for Patellar Instability

Background: Trochlear dysplasia is a well-described risk factor for patellofemoral instability. Despite its clear association with the incidence of patellar instability, it is unclear whether the presence of high-grade trochlear dysplasia influences clinical outcome after patellofemoral stabilization. Purpose: To determine whether isolated proximal soft tissue stabilization for patellofemoral instability is as successful in patients with high-grade dysplasia compared with low-grade or no dysplasia, as measured by disease-specific quality-of-life and pain scores. Study Design: Case series; Level of evidence, 4. Methods: A total of 277 patellofemoral stabilization procedures were performed during the study period. An isolated stabilization was performed in 233 patients, and 203 of these patients (87%) had adequate lateral radiographs and complete Banff Patella Instability Instrument (BPII) scores available for assessment. Of these, 152 patients underwent a medial patellofemoral ligament reconstruction (MPFL-R) and 51 patients received a medial patellofemoral ligament imbrication (MPFL-I). There were 21 patients with no trochlear dysplasia, 89 patients with low-grade dysplasia (Dejour type A), and 93 patients with high-grade dysplasia (Dejour types B-D). An independent-samples t test was used to determine the difference between the pre- and postoperative BPII scores. A Spearman rho correlation was calculated between 3 trochlear dysplasia groups and the BPII scores at a mean 24 months after patellofemoral stabilization. An independent-samples t test was used to assess the influence of trochlear bump size on outcomes by stratifying data and assessing for a relationship to BPII scores. Results: The independent-samples t test demonstrated statistically significant improvements in pre- to postoperative BPII scores for both groups. The MPFL-R group improved from a mean BPII score of 24.36 to 65.16 (P < .001), and the MPFL-I group improved from a mean of 28.92 to 73.45 (P < .01). For the MPFL-R patient cohort, the Spearman rho correlation demonstrated a significant relationship between postoperative BPII scores and presence of a trochlear bump and degree of dysplasia (P ≤ .05). Overall, a trochlear bump of ≥5 mm was associated with lower postoperative BPII scores (t(193) = 2.65, η2 = 0.04). Conclusion: This research has established a statistically significant correlation between trochlear dysplasia and disease-specific outcomes after MPFL-R surgery. Overall, there was evidence of significant improvement in disease-specific quality-of-life scores after patellofemoral stabilization surgery. This study is the largest cohort reported to date and therefore adds substantially to the evidence that trochlear dysplasia is a significant risk factor for and predictor of outcome among patients with patellofemoral instability.

Medial Retinaculum Plasty Versus Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability in Adults: A Randomized Controlled Trial

The purpose of this study was to evaluate the clinical results of medial retinaculum plasty (MRP) and medial patellofemoral ligament reconstruction (MPFLR) with concomitant lateral retinacular release with respect to imaging and functional results. Seventy patients with recurrent patellar instability were randomly divided into 2 groups based on their birth years (even/odd), receiving either MRP or MPFLR. Lateral retinacular release was also performed in all patients. Preoperatively, all patients received magnetic resonance imaging to evaluate the injury to the medial patellofemoral ligament. Computed tomography was performed before surgery and at follow-up. The subjective symptoms and functional outcome were evaluated preoperatively and postoperatively with the Kujala score, the Tegner activity score, and a subjective questionnaire. The physical apprehension test was examined, and redislocation was recorded. Patients were followed up for a mean period of 40 months (range, 24 to 55 months). The measurement results for the congruence angle, patellar tilt angle, and patellar lateral shift decreased significantly from the pretreatment measurements to the normal range at the latest follow-up, without a statistically significant difference between the 2 groups (P > .05). The median Kujala score had significantly improved after surgery. However, no statistically significant difference was found between the 2 groups at the latest follow-up (P > .05). In 6 cases in the MRP group (19%) and 3 in the MPFLR group (9%), we found patellar lateral shift that exceeded 1.5 cm but was less than 2.0 cm with a firm endpoint for the apprehension test, without a significant difference between the 2 groups. This prospective randomized study showed that MPFLR for recurrent patellar instability could achieve good clinical results, with a good congruous patellofemoral joint and good knee function. MRP could yield similar results to MPFLR for recurrent patellar instability in adults with medial patellofemoral ligament injuries from the patella or midsubstance portions. Level II, prospective comparative study.

The Role of Medial Retinaculum Plication Versus Medial Patellofemoral Ligament Reconstruction in Combined Procedures for Recurrent Patellar Instability in Adults

Background: The comparative clinical outcome of medial retinaculum plication (MRP) versus medial patellofemoral ligament reconstruction (MPFLR) for recurrent patellar instability in adults is unknown. Hypothesis: Arthroscopic MRP can yield similar results to MPFLR for recurrent patellar instability in adults. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: One hundred patients with recurrent patellar instability were randomly divided into 2 groups receiving either arthroscopic MRP or MPFLR. Lateral release and anteromedial or distal tibial tubercle transfers were also performed as indicated. Follow-ups were performed at 12, 24, and 60 months postoperatively, and computed tomography (CT) was performed immediately after the operation and at follow-up. The passive patella glide test was performed before surgery and at each follow-up point. The degree of knee function was evaluated preoperatively and at 2 and 5 years postoperatively using the International Knee Documentation Committee (IKDC), Lysholm, and Kujala rating scales. Survival analysis was performed, and redislocation or multiple episodes of patellar instability were considered as indicating failure. Results: Forty-three patients in the MRP group and 45 patients in the MPFLR group were followed for 5 years and received complete evaluations. The correction of the static patellar position deteriorated over time in both groups, but significantly better results were observed for the MPFLR group. The results of the passive patella glide test indicated more stable patellae in the MPFLR group at each follow-up point. Functional evaluations at 2 and 5 years (final Lysholm score, 69.3 ± 6.9 vs 86.9 ± 6.1; Kujala score, 73.8 ± 5.5 vs 87.4 ± 5.7) revealed statistically significant superior results in the MPFLR group. Finally, 4 patients (9.3%) in the MRP group and 1 (2.2%) in the MPFLR group experienced episodes of redislocation, and 7 patients (16.3%) in the MRP group and 3 (6.7%) in the MPFLR group experienced multiple episodes of patellar instability (P = .037). Kaplan-Meier survival analysis and a log-rank test indicated better results and a significantly higher survival rate (P = .006) in the MPFLR group. Conclusion: MPFLR results in better static patellar position and functional outcome than MRP in the treatment of recurrent patellar dislocation in adults.