Persistent morbidity after Medial Patellofemoral Ligament Reconstruction - A registry study with an eight-year follow-up on a nationwide cohort from 1996 to 2014

Specific considerations in female patients with patellar instability: current concepts

Prior literature suggests that patellofemoral instability (PFI) is significantly more prevalent in women than in men. This higher prevalence is commonly attributed to anatomical differences between sexes, particularly with patellofemoral alignment. These differences encompass a higher rate of trochlear dysplasia (TD), patella alta, an increased Q angle, and soft tissue imbalances. In recent years, worse outcomes have been reported in female patients after patellofemoral stabilization surgery using medial patellofemoral ligament reconstruction (MPFLr) alone or in combination with a tibial tubercle osteotomy (TTO), for this reason an "à la carte" plan (addressing the individuals anatomical risk factors) could be more appropriate for female patients.

Medial patellofemoral ligament reconstruction in skeletally immature patients without correction of bony risk factors leads to acceptable outcomes but higher failure rates

OBJECTIVES

To report outcomes and re-dislocation rates of medial patellar stabilizers reconstruction without bone procedures for correction of anatomical risk factors for patellar instability in skeletally immature patients; to compare isolated medial patellofemoral ligament (MPFL) reconstruction to combined MPFL and medial patellotibial ligament (MPTL) reconstruction in this population.

METHODS

Patients with open physis and bone abnormalities including patella alta and/or increased tibial tubercle-trochlear groove (TT-TG) distance and/or trochlear dysplasia underwent MPFL reconstruction, either isolated or associated with MPTL reconstruction. Preoperative, 1-year follow-up and the latest follow-up (5 years minimum) data were collected. Radiological and clinical evaluations were conducted, with special attention to failure rate. Comparison of results from isolated MPFL and combined MPFL/MPTL reconstructions was performed.

RESULTS

Twenty-nine patients were included, 19 in the isolated MPFL group (median 14 years old; follow-up 5.8 ​± ​1.7 years) and 10 in the combined MPFL/MPTL group (median 13.5 years old; follow-up 5.2 ​± ​1.4 years). Kujala and Tegner scores increased over time, although without statistically significant differences between the two groups at the latest follow-up (p ​= ​0.840 and p ​> ​0.999, respectively). During follow-up, 5 of 19 (26.3%) isolated MPFL and 2 of 10 (20%) MPFL/MPTL reconstructions experienced recurrence of patellar dislocation (p ​> ​0.999). Trochlear dysplasia type D (p ​= ​0.028), knee rotation (p ​= ​0.009) and lateral patellar tilt angle (p ​= ​0.003) were associated with patellar instability recurrence. The isolated MPFL group showed increased laxity on physical exam at the latest follow-up compared to the 1-year follow-up (patellar glide test (p ​= ​0.002), patellar tilt test (p ​= ​0.042) and subluxation in extension (p ​= ​0.019). This increased laxity was not observed in the MPFL/MPTL group (p ​> ​0.999). Comparing both groups, the glide test was significantly better in the combined MPFL/MPTL group in comparison to the isolated MPFL reconstruction group at the latest follow-up (p ​= ​0.021).

CONCLUSION

MPFL reconstruction in isolation or combined with MPTL reconstruction in skeletally immature patients with additional uncorrected anatomical patellofemoral abnormalities leads to acceptable clinical outcomes within a minimum of 5 years follow-up, although has a high failure rate of 24.1%. Addition of a MPTL reconstruction to the MPFL may result in decreased patellar laxity on physical exams, as demonstrated by better patellar glide test, patellar tilt test and subluxation in extension.

LEVEL OF EVIDENCE

Level III; retrospective cohort study.

Medial patellofemoral ligament reconstruction is superior to active rehabilitation in protecting against further patella dislocations

PURPOSE

Isolated reconstruction of the medial patellofemoral ligament (MPFL-R) has become the predominant stabilizing procedure in the treatment of recurrent lateral patellar dislocation (LPD). To minimize the risk of re-dislocations, isolated MPFL-R is recommended in patients with no significant trochlea dysplasia and tibial tuberosity trochlear groove distance < 20 mm on computed tomography (CT). Incidentally, these criteria are the same that are used to identify first time LPD patients where conservative treatment is recommended. The purpose of this study was therefore to compare MPFL-R with active rehabilitation for patients with recurrent LPD (RLPD) in absence of the above mentioned underlying anatomical high-risk factors for further patellar dislocations.

METHODS

RLPD-patients aged 12-30 without underlying anatomical high-risk factors for further LPD were randomized into treatment either with isolated MPFL-R or active rehabilitation provided and instructed by a physiotherapist. All patients underwent diagnostic arthroscopy for concomitant problems. The main outcome measure was persistent patellar instability at 12 months. Knee function at baseline and 12 months was asses using the following patient reported outcomes measures (PROMS); KOOS, Kujala, Cincinnati knee rating, Lysholm score and Noyes sports activity rating scale.

RESULTS

Between 2010 and 2019, 61 patients were included in the study (MPFL-R, N = 30, Controls, N = 31). Persistent patellar instability at 12 months was reported by 13 (41.9%) controls, versus 2 (6.7%) in the MPFL-group (RR 6.3 (95% CI 1.5-25.5). No statistically significant differences in activity level were found between the MPFL-group and the Controls at neither baseline nor follow up. The patients with persistent instability at 12 months did not score significantly lower on any of the PROMs compared to their stable peers, regardless of study group.

CONCLUSION

Patients with recurrent patellar dislocations have a six-fold increased risk of persistent patellar instability if treated with active rehabilitation alone, compared to MPFL-R in combination with active rehabilitation, even in the absence of significant anatomical risk factors. Active rehabilitation of the knee without MPFL-R improves patient reported knee function after one year, but does not protect against persistent patellar instability.

CLINICAL RESULTS OF MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION

Objective

To assess clinical results of patients who underwent medial patellofemoral ligament (MPFL) reconstruction after a minimum of two years of follow-up.

Methods

Patients' medical records were assessed for residual instability, patient satisfaction, and post-operative functional outcomes.

Results

Fifty-one patients were analyzed, out of which 56.87% were women. Patients' mean age was 30.8 years (16 to 57 years). The mean follow-up time was 68.7 months (37 to 120 months). Length between first dislocation and surgery was less than 1 year for 58.82% of patients, between 1 and 5 years for 37.25%, and over 5 years for 3.93%. Patients showed a high degree of satisfaction (96.08% would undergo surgery again), with recurrence rate of 11.76%. Twenty-two patients reported knee symptoms, including pain from movements (72.72%), weakness (18.18%), constant pain (13.63%), and crepitus (4.54%). Considering dissatisfied patients, patients with dislocation recurrence, and patients with symptoms, five cannot practice physical activity, out of which only three blame their knee.

Conclusion

MPFL reconstruction showed a recurrence rate of 11.7%, with high patient satisfaction, good functional results, and high rate of return to sports, after a minimum of two years of follow-up. Level of Evidence IV, Case Series.

Comparing Sex-Specific Outcomes After Medial Patellofemoral Ligament Reconstruction for Patellar Instability: A Systematic Review

BACKGROUND

The impact of patient sex on outcomes after medial patellofemoral ligament ligament reconstruction (MPFLR) has not been well studied.

PURPOSE

To conduct a systematic review to determine sex-based differences in outcomes after MPFLR for patellar instability and the proportion of studies examining this as a primary or secondary purpose.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review was performed using the PubMed, Cochrane Library, PubMed Central, Ovid, and Embase databases according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they were written in English, were performed on humans, consisted of patients who underwent MPFLR with allograft or autograft, evaluated at least 1 of the selected outcomes comparing male and female patients, and had statistical analysis available for relevant findings. Excluded were case reports, review studies or systematic reviews, studies that did not evaluate at least 1 sex-specific outcome, studies that included other injuries associated with patellofemoral instability injury, cadaveric studies, and those in which patients underwent concomitant procedures.

RESULTS

The initial search yielded 3470 studies; 2647 studies remained after removing duplicates. Of the 401 studies that underwent full-text review, 10 met all inclusion criteria and were included for quantitative analysis. A meta-analysis could not be performed given the heterogeneity within the data set. Of the 2647 studies evaluated in this study, only 2 (0.08%) studies examined the impact of patient sex on MPFLR outcomes as a primary purpose and only 8 (0.30%) studies explored it as a secondary purpose.

CONCLUSION

Only 0.38% of the articles compared outcomes between male and female patients after MPFLR. The limited data available were too heterogenous to draw any concrete conclusions about the impact of patient sex on outcomes after MPFLR. Further research in this area is warranted, as findings may influence treatment plans and improve patient outcomes.

Traumatic Patellar Dislocations in Childhood and Adolescents

Patellar instability and associated patellar dislocation can result in significant pain, disability, and associated injuries in young athletes. The patellofemoral joint is a complex articulation with stabilizing restraints, both medially and laterally, that help guide the patella into the corresponding trochlear groove as the knee cycles through an extension-to-flexion arc. In addition to soft tissue injuries, many osseous aberrancies can contribute to patellar instability in young athletes, including trochlear dysplasia, patella alta, and axial and coronal plane abnormalities. There is a role for nonoperative treatment in these young athletes; however, if recurrent or associated injuries are identified surgical intervention is warranted. Correct diagnosis of the underlying cause of the patellar instability is paramount to developing a surgical plan that will yield the most favorable outcome for these young athletes.

Evaluation of Patellar Contact Pressure Changes after Static versus Dynamic Medial Patellofemoral Ligament Reconstructions Using a Finite Element Model

OBJECTIVES

To evaluate the effect of various medial patellofemoral ligament (MPFL) fixation techniques on patellar pressure compared with the native knee.

METHODS

A finite element model of the patellofemoral joint consisting of approximately 30,700 nodes and 22,200 elements was created from computed tomography scans of 24 knees with chronic lateral patellar instability. Patellar contact pressures and maximum MPFL graft stress at five positions of flexion (0°, 30°, 60°, 90°, and 120°) were analyzed in three types of MPFL reconstruction (MPFLr): (1) static/anatomic, (2) dynamic, using the adductor magnus tendon (AMT) as the femoral fixation, and (3) dynamic, using the quadriceps tendon as the attachment (medial quadriceps tendon-femoral ligament (MQTFL) reconstruction).

RESULTS

In the static/anatomic technique, the patellar contact pressures at 0° and 30° were greater than in the native knee. As in a native knee, the contact pressures at 60°, 90°, and 120° were very low. The maximum MPFL graft stress at 0° and 30° was greater than in a native knee. However, the MPFL graft was loose at 60°, 90°, and 120°, meaning it had no tension. In the dynamic MPFLr using the AMT as a pulley, the patellar contact pressures were like those of a native knee throughout the entire range of motion. However, the maximum stress of the MPFL graft at 0° was less than that of a native ligament. Yet, the maximum MPFL graft stress was greater at 30° than in a native ligament. After 30° of flexion, the MPFL graft loosened, similarly to a native knee. In the dynamic MQTFL reconstruction, the maximum patellar contact pressure was slightly greater than in a normal knee. The maximum stress of the MPFL graft was much greater at 0° and 30° than that of a native MPFL. After 30° of flexion, the MQPFL graft loosened just as in the native knee.

CONCLUSIONS

The patellar contact pressures after the dynamic MPFLr were like those of the native knee, whereas a static reconstruction resulted in greater pressures, potentially increasing the risk of patellofemoral osteoarthritis in the long term. Therefore, the dynamic MPFLr might be a safer option than a static reconstruction from a biomechanical perspective.

Functional outcome after recurrent patellar dislocation : Comparison of two surgical techniques-Medial patellofemoral ligament reconstruction (MPFL) vs. Elmslie Trillat procedure

Background

There is no final consensus regarding the ideal surgical technique for the treatment of patellar dislocation. The aim of this retrospective pilot study was to describe muscle strength, body composition, self-reported physical performance, and pain in male patients after patellar dislocation treatment with two different surgical techniques: medial patellofemoral ligament (MPFL) reconstruction vs. the Elmslie-Trillat procedure.

Methods

Isokinetic testing of knee extensor muscles was performed using a Biodex System 3 pro dynamometer at an angular velocity of 60°/s. Body composition was measured with bioelectrical impedance analysis (Nutribox). Self-reported physical performance and pain were assessed by the SF-36 subscales of physical functioning, role physical and bodily pain. The outcome variables of peak torque normalized to participant’s body mass (Nm/kg), lean body mass, phase angle, self-reported physical performance, and pain were compared between the study groups.

Results

Of the 12 included male patients, 6 had been treated with MPFL reconstruction (age: median = 33 years, range = 18–38 years; BMI: median = 26 kg/m², range = 23–29) and 6 with the Elmslie-Trillat procedure (age: median = 26 years, range = 19–32 years; BMI: median = 23 kg/m², range = 19–28). No statistically significant differences were found between the groups in any outcome parameter of muscle strength, body composition, self-reported physical performance, or pain.

Conclusions

The results of the present pilot study revealed that MPFL reconstruction shows equal results to the Elmslie-Trillat procedure, with respect to isokinetic knee muscle strength, body composition, self-reported physical performance and pain in male patients suffering from recurrent patellar dislocation.