Isolated and combined medial patellofemoral ligament reconstruction in revision surgery for patellofemoral instability: a prospective study

Synthetic suture tape for medial patellofemoral ligament reconstruction is an effective treatment for complex paediatric patellofemoral instability

PURPOSE

To assess the outcomes of medial patellofemoral ligament (MPFL) reconstruction using synthetic suture tape in paediatric patients with patellofemoral instability (PFI).

METHODS

This ambispective comparative study, conducted from 2014 to 2022, included paediatric patients who underwent MPFL reconstruction with synthetic suture tape and had a minimum follow-up of 1 year. Pre- and postoperative clinical and functional outcomes, patient satisfaction and complications were assessed.

RESULTS

The study comprised 22 patients (29 knees), with a median age at surgery of 14.4 years (interquartile range [IQR] 10.9-16.7) and a median follow-up of 46.5 months (24.7-66). Notably, 13 knees (44.8%) had open growth plates at the time of surgery. The cohort included patients with Down syndrome (3 patients), Ehlers-Danlos (2), arthrogryposis (1), generalized joint hypermobility (8) and previous unsuccessful PFI surgeries (8). Concomitant procedures were performed on 16 knees. Postoperatively, improvements were observed in all but one patient, who reported residual pain. There were two other complications: one suture-tape rupture and one surgical wound infection. Functional scores significantly improved: Kujala, +14 points (7-29) (p < 0.001); IKDC, +10.5 points (5.2-25.3) (p < 0.001); Tegner, +2 points (0-4) (p < 0.001); Lysholm, +15 points (0-37.5) (p < 0.001). Most patients achieved excellent outcomes by Crosby-Insall criteria (21 patients, 72.4%) and reported high satisfaction (23 patients, 79.3%).

CONCLUSIONS

MPFL reconstruction using synthetic suture tape is a viable and effective treatment for paediatric patients with PFI, particularly for those with connective tissue disorders, generalized joint hypermobility or past surgical failures, significantly enhancing clinical and functional outcomes with an acceptable complication rate.

LEVEL OF EVIDENCE

Level IV.

Early Postoperative Rapid Rehabilitation Yields More Favorable Short-term Outcomes in Patients Undergoing Patellar Realignment Surgery for Recurrent Patellar Dislocation: A Prospective Randomized Controlled Study

BACKGROUND

Use of a rapid rehabilitation protocol for postoperative recovery after recurrent patellar dislocation (RPD) has gradually gained attention; nonetheless, evidence of its safety and effectiveness is lacking.

PURPOSE

To compare the short-term postoperative outcomes of early rapid rehabilitation with those of conservative rehabilitation in patients with RPD.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A total of 50 patients with RPD who underwent tibial tubercle osteotomy combined with medial patellofemoral ligament reconstruction were enrolled between January 2018 and February 2019. Postoperatively, the patients were randomly assigned to either the early rapid group (rapid group; n = 25 patients) or the conservative group (control group; n = 25 patients) for rehabilitation training. The rapid group underwent faster progression in weightbearing and range of motion (ROM) training. Knee joint functional scores, ROM, bilateral thigh circumference differences, and imaging data were recorded preoperatively and at 6 weeks and 3, 6, 12, and 24 months postoperatively for comparison. Postoperative complications were recorded over the 24-month follow-up period.

RESULTS

The baseline data did not significantly differ between the 2 groups. Postoperatively, compared with the control group, the rapid group had higher Tegner scores at 6 weeks and 3 months; higher Lysholm scores at 3 and 6 months; higher International Knee Documentation Committee scores at 6 weeks, 3 months, and 12 months; better ROM; and smaller bilateral thigh circumference differences at 24 months (P < .05 for all). However, no differences were observed in the Tegner, Lysholm, and International Knee Documentation Committee scores at 24 months postoperatively. At the 6-week and subsequent follow-up visits, the Caton and Insall indices were lower in the control group than in the rapid group (P < .01 for all). Moreover, compared with the control group, the rapid group had a lower incidence of patella baja at 24 months (0% vs 17%) and fewer complications during the whole follow-up period (P < .01).

CONCLUSION

Early rapid postoperative rehabilitation appears to be safe and effective for patients who undergo tibial tubercle osteotomy combined with medial patellofemoral ligament reconstruction to treat RPD. In the short term, this approach was shown to be more advantageous than conservative rehabilitation in improving functional scores, allowing an earlier return to daily activities, although the lack of difference at 24 months implies no long-term benefits. In addition, it potentially helped to prevent the occurrence of complications, including patella baja.

REGISTRATION

ChiCTR1800014648 (ClinicalTrials.gov identifier).

Isolated medial patellofemoral reconstruction outcomes: A systematic review and meta-analysis

BACKGROUND

Treatment of patellar instability remains up for debate, and a combination of tibial tubercle osteotomy and medial patellofemoral ligament reconstruction (MPFLr) of the medial patellofemoral ligament (MPFL) has become the mainstay treatment for recurrent lateral patellar dislocation. Due to limited small studies, there remains a variety of surgical techniques still being practiced. The use of MPFL reconstruction, in isolation, has demonstrated promise.

PURPOSE

The purpose of this systematic review and meta-analysis is to investigate if isolated medial patellofemoral ligament reconstruction (iMPFLr) can safely and efficaciously restore knee stability and to present the patient demographics, surgical techniques, graft choices, clinical outcomes, and complications after iMPFLr for recurrent patellar dislocation (RPD).

METHODS

A review of the current literature according to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, yielded 299 abstracts. Twenty-seven articles met the inclusion/exclusion criteria accounting for 1200 patients. Data was pooled and analyzed focusing on patient demographics, graft type used, Kujala, International Knee Documentation Committee (IKDC), Lysholm, Tegner, and complications.

RESULTS

Across all studies the weighted mean age was found to be an average of 24.5 years, BMI was 24.9 kg/m2, follow-up was 47.3 months, as 67% were female, TT-TG distance was 15.3 mm, and Caton Deschamps index 1.11. The pooled effect size difference of pre versus post assessment of Kujala was -2.8, IKDC was -4.5, Lysholm was -6.4, and Tegner was -0.74. The pooled complication rate was found to be 8% across all included studies. A subgroup analysis was also performed, specifically looking at how single bundle, double bundle, gracilis, semitendinosus and knee angle during fixation effect outcome data.

CONCLUSION

This systematic review and meta-analysis demonstrates that isolated MPFL reconstruction is a safe and effective treatment for recurrent patellar dislocations. Given the efficacy of isolated MPFL reconstruction, future investigations should aim to uncover the exact TT-TG distance, trochlear dysplasia, and patella alta grade for selecting patients to undergo this procedure. Furthermore, more primary research needs to be conducted on this topic due to the overall lack of published data from randomized controlled studies and no broad standardization of outcome measurements.

LEVEL OF EVIDENCE

(4) Systematic Review and Meta-Analysis.

Isolated medial patellofemoral ligament reconstruction for recurrent patellofemoral instability: analysis of outcomes and risk factors

Background

The medial patellofemoral ligament (MPFL) is always damaged after patellar dislocation. In selected patients, MPFL reconstruction is necessary to restore a correct patellar tracking. Despite the large number of different techniques reported to reconstruct the MPFL, there is no consensus concerning the optimal procedure, and debates is still ongoing. The present study analysed the results after isolated MPFL reconstruction in patients with patellofemoral instability. Furthermore, a subgroup analysis of patients presenting pathoanatomical risk factors was made.

Methods

In November 2020, the main electronic databases were accessed. All articles reporting the results of primary isolated MPFL reconstruction for recurrent patellofemoral instability were considered for inclusion. Only articles reporting a minimum 12-month follow-up were eligible.

Results

Data from a total of 1777 knees were collected. The mean age of the patients involved was 22.8 ± 3.4 years. The mean follow-up was 40.7 ± 25.8 months. Overall, the range of motion (+ 27.74; P < 0.0001) and all the other scores of interests improved at last follow-up: Kujala (+ 12.76; P = 0.0003), Lysholm (+ 15.69; P < 0.0001), Tegner score (+ 2.86; P = 0.006). Seventy-three of 1780 patients (4.1%) showed a positive apprehension test. Thirty of 1765 patients (1.7%) experienced re-dislocations, while 56 of 1778 patients (3.2%) showed persisting joint instability. Twenty-five of 1786 patients (1.4%) underwent revision surgeries.

Conclusion

Isolated MPFL reconstruction for recurrent patellofemoral instability provides reliable surgical outcomes. Patients with pathoanatomical predisposing factors reported worse surgical outcomes.

Isolated versus combined medial patellofemoral ligament reconstruction for lateral instability of the patella

INTRODUCTION

Medial patellofemoral ligament reconstruction (MPFLR) is regularly combined with a tibial tuberosity transfer (TTT) in cases of recurrent patellar instability with underlying structural deformity. However, these indications for a TTT have recently come into question. This study aimed to assess the traditional indications by comparing the outcomes of isolated and combined MPFLR for the treatment of recurrent lateral patellar dislocation.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included studies were those which reported the outcomes of either isolated or combined or both MPFLR. Studies were required to report at least one of the following: redislocation rate, revision due to instability, or the Kujala score.

RESULTS

We found no difference between isolated and combined MPFLR in terms of redislocation ( p = 0.48), revisions due to instability ( p = 0.36), positive apprehension tests ( p = 0.25), or the Kujala score ( p = 0.58). Combined reconstruction presented more complications compared to isolated procedures ( p = 0.05). Subgroup analysis revealed no significant difference between studies investigating isolated medial patellofemoral ligament reconstruction MPFLR performed in patients with normal tibial tuberosity-trochlear groove (TT-TG) distances only or in patients with both normal and elevated TT-TG distances.

CONCLUSIONS

According to the published data, there is no difference in outcomes between isolated and combined MPFLR. Underlying structural deformity did not demonstrate any significant effect on the success of the isolated MPFLR. Although there are definite indications for combined reconstruction, the current evidence suggests that our inclusion criteria may not be entirely correct. Further study is required to clarify and refine the true indications for combined MPFLR.

LEVEL OF EVIDENCE

III, meta-analysis of nonrandomized studies.

Self-reported and performance-based outcomes following medial patellofemoral ligament reconstruction indicate successful improvements in knee stability after surgery despite remaining limitations in knee function

PURPOSE

To evaluate short- to midterm outcomes of medial patellofemoral ligament reconstruction (MPFL) using patient-reported outcome measures and functional testing.

METHODS

Twenty-four patients were examined regarding knee function after MPFL reconstruction, with a mean follow-up time of 45.3 ± 18.4 months since surgery. Knee function was evaluated using the Tegner score, VAS, the knee injury and osteoarthritis outcome score (KOOS), the Lysholm score, SF-36 and EQ-5D-3L as well as functional scores. A group of uninjured persons of the same age and same gender composition was used for comparison.

RESULTS

Eight (40%) patients managed to return to their pre-injury activity level. Five (25%) patients stated that they had experienced further patella dislocations after surgery but only two (10%) had sought medical help. Patients showed significantly poorer results in all PROMs compared to controls. The results obtained with SF-36 showed significant differences in physical health between the groups, but not in mental health. The functional performance test results showed overall poorer results for the patients versus controls: 11.5 sets for the square jump (6.7-15.7) versus 21 sets (18-26), 11.5 sets for the step-down test (6.5-15) versus 22 sets (18-26), and 77 cm for the single-leg hop for distance (32.2-110.5) versus 126 cm (115-37); all (P < 0.005).

CONCLUSIONS

After MPFL reconstruction, patients do not regain normal knee function, as measured by PROMs and functional tests, compared to an uninjured control group. Patients should be informed about residual functional limitations despite improved stability.

LEVEL OF EVIDENCE

III.

Treatment of patellar dislocation with arthroscopic medial patellofemoral ligament reconstruction using gracilis tendon autograft and modified double-patellar tunnel technique: minimum 5-year patient-reported outcomes

BACKGROUND

The purpose of this study was to retrospectively analyze the clinical outcomes of patients with recurrent patellar dislocation who underwent arthroscopic medial patellofemoral ligament (MPFL) reconstruction using gracilis tendon autograft and a modified double-patellar tunnel method. We hypothesized that our modified method would provide good clinical outcomes.

METHODS

Patients who underwent arthroscopic MPFL reconstruction with autograft gracilis tendon and modified double-patellar tunnels technique for recurrent patellar dislocation and were followed up for a minimum of 5 years were identified, and the clinical and follow-up data were retrospectively analyzed. Preoperatively, joint hypermobility was assessed with the Beighton score. The Insall-Salvati ratio, TT-TG distance, and Q angle were measured on radiographic images. Patient-reported outcomes including the Kujala, Lysholm, and Tegner scores were collected preoperatively and postoperatively. Patient satisfaction was assessed at the end of 5 years. Complications and recurrent dislocation occurring after surgery were recorded.

RESULTS

A total of 79 patients (94 knees) were enrolled; of these, 13 (16.5%) were lost to follow-up. The data of 66 patients (80 knees) were available for final analysis. Mean age at surgery was 21.3 ± 7.8 years. Mean follow-up time was 66.1 ± 5.5 months (range, 60-78 months). Postoperative patient-reported outcome was not associated with Beighton score, Insall-Salvati ratio, or TT-TG distance. Q angle was negatively correlated to Kujala scores and Lysholm scores. Severity of trochlear dysplasia was not associated with postoperative patient-reported outcome. The mean Kujala score increased from 69.4 ± 7.9 to 96.1 ± 1.9, the mean Tegner score increased from 3.1 ± 1.3 to 5.9 ± 1.3, and the mean Lysholm score increased from 73.5 ± 14.6 to 95.3 ± 3.4. Two patients experienced recurrent patellar dislocation during follow-up.

CONCLUSIONS

MPFL reconstruction using autologous gracilis tendon under arthroscopy appears to be a reliable and safe method for treating recurrent patellar dislocation.

LEVEL OF EVIDENCE

Level IV.

[Diagnosis and therapy of chronic patellofemoral instability]

The chronic patellofemoral instability is a multifactorial disease, which is mostly congenital. Luxation of the patella is mainly atraumatic. Sole conservative treatment is often unsuccessful. Surgical treatment is needed in most cases and requires consideration of all pathologic changes of the patella-stabilizing anatomic structures. Rupture of the medial patellofemoral ligament is almost pathognomonic. In addition, the frontal mechanical axis, rotation of femur and tibia, the trochlear shape, the distance from the tibial tuberosity to the trochlear sulcus and the patellar height play an important role. Often, in addition to soft tissue reconstruction, the bony alignment needs to be corrected. Consideration of risk factors in both adult and adolescent patients is needed to avoid recurrent instability.

An Updated Overview of the Anatomy and Function of the Proximal Medial Patellar Restraints (Medial Patellofemoral Ligament and the Medial Quadriceps Tendon Femoral Ligament)

The medial patellofemoral ligament (MPFL) has been widely accepted to function as "the primary static restraint to lateral patellar displacement." However, current growing evidence suggests that there is a complex of medial patellofemoral/tibial ligaments, both proximal [MPFL, and medial quadriceps tendon femoral ligament (MQTFL)], and distal (medial patellotibial ligament and the medial patellomeniscal ligament) which restrain lateral patellar translation at different degrees of knee flexion. Specifically, the MQTFL has gained popularity over the last decade because of pure soft tissue attachments into the extensor mechanism that allow for avoidance of drilling tunnels into the patella during reconstruction. The purpose of this article was to report on the current knowledge (anatomy, biomechanics, diagnosis, indications for surgery, and techniques) on the proximal medial patellar restraints, namely the MPFL and the MQTFL, collectively referred to as the proximal medial patellar restraints.

Does patella alta lead to worse clinical outcome in patients who undergo isolated medial patellofemoral ligament reconstruction? A systematic review

INTRODUCTION

The aim of this systematic review is to determine the effect of patella height on clinical outcomes after isolated MPFL reconstruction for patella instability. Our primary hypothesis is that patients with patella alta report similar outcomes after isolated MPFL reconstruction compared to patients with normal patella height.

METHODS

A review of the literature was performed according to the PRISMA guidelines. PubMed, EMBASE, and the Cochrane Library were searched from inception to January 10th 2018. Studies were identified using synonyms for "medial patellofemoral ligament", "reconstruction" and "patella alta".

RESULTS

The search resulted in 467 reports on PubMed, 175 on EMBASE and 3 on the Cochrane Library. We included and analyzed in detail six studies describing outcomes after isolated medial patellofemoral ligament reconstruction with regard to patellar height. We found that both patients with patella alta and normal patella height reported satisfactory outcomes after isolated medial patellofemoral ligament reconstruction. However, because of applied exclusion criteria in the included studies the total number of patients with severe patella alta was small (13/74 patients with patella alta, 18%).

CONCLUSIONS

Based on the current literature we suggest that additional tibial tubercle distalisation is not mandatory in patients with mild patella alta (Caton-Deschamps Index 1.2-1.4). To assess the best indications for different surgical procedures for patients with patella instability future research is needed to develop a clear and uniform definition of relevant patella alta.

LEVEL OF EVIDENCE

III.

The medial patellofemoral complex

PURPOSE OF REVIEW

The purpose of this review is to describe the current understanding of the medial patellofemoral complex, including recent anatomic advances, evaluation of indications for reconstruction with concomitant pathology, and surgical reconstruction techniques.

RECENT FINDINGS

Recent advances in our understanding of MPFC anatomy have found that there are fibers that insert onto the deep quadriceps tendon as well as the patella, thus earning the name "medial patellofemoral complex" to allow for the variability in its anatomy. In MPFC reconstruction, anatomic origin and insertion points and appropriate graft length are critical to prevent overconstraint of the patellofemoral joint. The MPFC is a crucial soft tissue checkrein to lateral patellar translation, and its repair or reconstruction results in good restoration of patellofemoral stability. As our understanding of MPFC anatomy evolves, further studies are needed to apply its relevance in kinematics and surgical applications to its role in maintaining patellar stability.

Clinical outcomes after revision surgery for medial patellofemoral ligament reconstruction

PURPOSE

Medial patellofemoral ligament reconstruction (MPFL-R) is the standard surgical intervention for patella instability. However, limited knowledge exists concerning the causes for failure, and outcome after revision MPFL-R. The purpose of this study is to evaluate the causes of primary MPFL-R failure and clinical outcomes after revision MPFL-R.

METHODS

Twenty-three patients (6 males and 17 females) with failed primary MPFL-R underwent isolated revision MPFL-R or combined revision MPFL-R with tibial tuberosity osteotomy (TTO). The mean age was 23 (SD 8.6). Prior to surgery, dysplasia of the patellofemoral joint, sulcus angle, Insall-Salvati index, cartilage lesions, tibial tuberosity trochlear groove (TTTG) distance, and tunnel placement were evaluated by magnetic resonance imaging (MRI). Their scores on the Kujala Anterior Knee Pain Scale and pain scores were assessed prior to surgery, 1 year post-operatively and at final follow-up. The mean follow-up time was 44 months (median range 39). The radiographic characteristics and clinical outcomes were compared with a 224 primary MPFL-R patient cohort (240 knees).

RESULTS

Non-anatomical fixation of the graft at the medial femoral condyle after primary MPFL-R was seen in 67% of revision patients with anterior/proximal misplacement in most cases. Severe trochlear dysplasia Dejour types C and D were seen in 36% of the patients compared to 30% of primary MPFL-R patients (NS). The mean Kujala Anterior Knee Pain Scale score at final follow-up was 61.7 (SD 18.8) compared to 80.3 (SD 18) in primary MPFL-R patients (P < 0.01). The mean pain score at rest was 2.3 (SD 2.5) for revision MPFL-R patients compared to 1.7 (SD 2.5) in primary MPFL-R patients (NS) and their mean pain score during activity was 5.0 (SD 3.2) compared to 1.3 (SD 2.2) in primary MPFL patients (P < 0.001).

CONCLUSION

Although revision MPFL-R establishes acceptable patellar stability, the subjective outcomes after revision MPFL-R do not improve significantly, and are poorer than after primary MPFL-R. Non-anatomical graft position can be an important cause of MPFL-R failure. The clinical relevance of this study is that it shows that it may be difficult to improve self-reported outcomes in revision MPFL-R patients.

LEVEL OF EVIDENCE

III.

Medial patellotibial ligament and medial patellomeniscal ligament: anatomy, imaging, biomechanics, and clinical review

PURPOSE

The purpose of this article is to review anatomical, biomechanical, and clinical data of the medial patellotibial ligament (MPTL) and medial patellomeniscal ligament (MPML), as well as studies focusing on the medial patellofemoral ligament (MPFL) but with relevant data about the MPTL and MPML.

METHODS

A literature search of articles specifically addressing the MPTL and/or MPML was included along with studies focusing on the MPFL but with relevant data about the MPTL and MPML.

RESULTS

The medial patellar ligaments responsible for maintaining the stability of the patellofemoral (PF) joint include the MPFL, the MPTL, and the MPML. The MPFL is considered the primary restraint to lateral patellar translation, while the latter two are considered secondary restraints. There is robust literature on the anatomical, imaging, and biomechanical characteristics of the MPFL, and also the clinical outcome of its injury and surgical reconstruction; much less is known about the MPTL and MPML. Isolated MPFL reconstruction has good clinical and functional outcomes, with a low failure rate when defined as frank re-dislocation. Complications, including continued episodes of patellar apprehension and subluxation, remain present in most series. In addition, the current literature primarily includes a homogeneous population with few excessive anatomic dysplastic factors. There is lack of knowledge on the role of MPTL and MPML in (potentially) aiding patella stabilization and improving clinical outcomes. Understanding the role of the medial-sided patellar ligaments, in particular the role of the secondary stabilizers, in PF function and injury will aid in this goal.

CONCLUSION

MPTL and MPML have consistent basic science literature, as well as favorable clinical outcomes of surgical patellar stabilization with reconstruction of the MPTL. However, there is much heterogeneity among clinical case series and lack of comparative studies to allow clear indication for the role of isolated or combined surgical reconstruction in patellar stabilization. Therefore, this comprehensive review helps understand the current knowledge and the possible applications in the orthopedic clinical practice.

LEVEL OF EVIDENCE

V.

Modified adductor sling technique: A surgical therapy for patellar instability in skeletally immature patients

BACKGROUND

Due to open femoral physis the therapy of patellar instability in skeletally immature patients is challenging. We developed a modified surgical technique of the 'Adductor-Sling-Approach' by Sillanpää. The purpose of this study was to evaluate the clinical outcome of the operative technique and to analyse the reasons for failure.

METHODS

Thirty 'modified adductor sling' reconstructions in 28 patients were included in the study. From 2010 to 2016 modified adductor sling reconstruction was performed by looping the gracilis or semitendinosus tendon around the adductor magnus tendon and attaching it at the medial facet of the patella. Clinical outcome was retrospectively evaluated at a mean follow up of 25.6months (range 12-43). The evaluation also included subjective International Knee Documentation Committee (IKDC), Lysholm Score, Kujala Score and Tegner Activity Score.

RESULTS

The average age at the time of operation was 15.10years (range 11-17). Eighty-seven percent of the patients, who underwent the modified adductor sling technique, gained a stable patella and excellent results in postoperative scores. Recurrent dislocation occurred in four of 30 cases (13%). Analysis showed that possible reasons for failure of the tendon graft could be maltracking of the patella due to patella alta, trochlear dysplasia or an elevated tibial tuberosity to trochlear groove distance.

CONCLUSION

The modified adductor sling technique for MPFL reconstruction in children and adolescents showed elevated redislocation rates. Only in absence of additional patellofemoral maltracking, caused by elevated tibial tubercle to trochlear groove distance (>15mm), patella alta or especially severe trochlear dysplasia, the modified adductor sling technique could be recommended.

Clinical results after treatment for bidirectional patellar subluxation: Minimum 2-years follow-up

BACKGROUND

We describe the preliminary clinical results of a patellar stabilization technique to treat bidirectional patellar subluxation (BPS).

METHODS

Patients: six patients (one male, five females; mean age 30.2years) underwent this procedure with a minimum of 24months follow-up. Patients were assessed for clinical instability, patellar complications, and need for revision surgery. Patient functional outcomes were evaluated using the criteria of Crosby and Insall and the Kujala Anterior Knee Pain Scale at the time of final follow-up. Patient satisfaction was assessed using a subjective questionnaire.

OPERATIVE TECHNIQUE

A semitendinosus tendon autograft is coursed through a transverse tunnel in the distal quadriceps tendon. The medial and lateral aspects of the graft are passed from the quadriceps tendon within subfascial tunnels to the MPFL attachment site and lateral epicondyle, respectively. The graft is fixed in 60° of knee flexion with suture anchors.

RESULTS

Surgery for recurrent instability was performed in one case. There were no cases of infection, quadriceps tendon rupture, or patella fracture. At average follow-up of 29.2months (range, 24 to 38months), outcomes were good to excellent in 4/6 of cases. Kujala scores improved significantly from 33.3 (range, three to 58) preoperatively to 70.8 (range, 39 to 96) postoperatively (p<0.05). 5/6 patients reported being satisfied to completely satisfied with their result.

CONCLUSION

Patients undergoing bidirectional patellar stabilization with a single tendon graft showed improved postoperative functional scores. The technique is successful in reducing pain and restoring bidirectional patellar stability at 2-years follow-up.

LEVEL OF EVIDENCE

IV, retrospective case series.

The influence of medial patellofemoral ligament reconstruction on clinical results and sports activity level

OBJECTIVES

The aim of this study was to demonstrate postoperative outcomes and return to regular physical and sports activities at average of 6 years after patellar stabilization with medial patellofemoral ligament (MPFL) reconstruction.

METHODS

Between November 2006 and January 2010, 31 isolated MPFL reconstructions in 29 patients with recurrent patellar dislocation were performed. Radiographs and magnetic resonance imaging were evaluated preoperatively. Knee function was assessed pre- and postoperative using Kujala score and the patient satisfaction, according to the International Knee Documentation Committee (IKDC) score. Tegner activity score was used for the evaluation of sports activity level.

RESULTS

The average follow-up was 6.4±1.2 years. All measured scores increased significantly at follow-up. The average Kujala score increased from 75±10 to 95±10, patient satisfaction according to IKDC score from 6.1±1.4 to 8.7±1.4 and Tegner activity score from 4.4±1.6 to 5.7±1.3. The Tegner activity score after surgery was significantly lower than the score before the patellar dislocation (6.7±1.3). There were no significant differences in Kujala postoperative score between women's and men's group (P=0.25). There was no significant correlation between body mass index and Kujala score postoperatively (P=0.11) and between age at surgery and Kujala scores postoperatively (P=0.56). Patients who were active in sports preoperatively had resumed sports activities in 88.5% after surgery, 69.6% of them returned to the same levels and 30.4% return to the lower levels.

CONCLUSION

Patellar stabilization with MPFL reconstruction is a safe and effective treatment method for all patients with patellofemoral instability and allows most patients to return to regular physical and sports activities after surgical intervention. Although sports activity level increased significantly after surgery, the same level of sports activity before the patellar dislocation has not been achieved.

Medial Patellofemoral Ligament Reconstruction Combined With Bony Procedures for Patellar Instability: Current Indications, Outcomes, and Complications

PURPOSE

The aim of this literature review is to analyze current indications, outcomes, and complication rates of medial patellofemoral ligament (MPFL) reconstruction associated with bony procedures in order to clarify efficacy and adoptability in selected patients with patellar instability.

METHODS

A systematic review of the literature was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search on PubMed, Medline, CINAHL, Cochrane, Embase, and Google Scholar databases was performed, using various combinations of the keywords patellar instability, MPFL reconstruction, tibial tubercle osteotomy, and trochleoplasty.

RESULTS

Fourteen of 501 articles were included. Indications for surgery included dysplasia and malalignment. All studies reported significant improvements in overall clinical outcomes. The most frequently used score was the Kujala score, with a mean value of 83.26. Functional failures ranged from 0% to 8.8%. Major complications were not described. Minor complications ranged from 0% to 40%. Reoperations ranged from 4.5% to 17.7%.

CONCLUSIONS

A combined approach seems indicated in patients with patellar instability, especially among those with high tibial tuberosity-trochlear groove or severe trochlea dysplasia. Indications for combined MPFL and bony procedure are influenced by anatomy, including dysplasia and malalignment. We are unable to identify an absolute indication. Bony procedures are associated with increased morbidity.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.

The Efficacy of Medial Patellofemoral Ligament Reconstruction Combined with Tibial Tuberosity Transfer in the Treatment of Patellofemoral Instability

A systematic review of the literature was undertaken to evaluate the efficacy of medial patellofemoral ligament (MPFL) reconstruction combined with tibial tuberosity transfer (TTT) in the treatment of patellofemoral instability. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a systematic search was carried out to identify and review the published literature pertinent to MFPL reconstruction combined with TTT. Relevant studies were critically appraised with narrative data synthesis. Studies that met the eligibility criteria were suitable for appraisal and consisted of case series and therapeutic series (levels IV & III). All studies had inherent variations in outcomes reporting and limited follow-up. Combined treatment offers restoration of normal anatomy, thus adding clinical value to the currently recommended anatomic approach to MPFL reconstruction. Nevertheless, the current body of evidence does not determine the threshold at which patellofemoral axis requires the need for adjunctive distal realignment as opposed to MPFL reconstruction alone. This review highlighted numerous recurring limitations in the conduct and presentation of the studies, which inadvertently mitigated the interpretation of their results. Future priority should be awarded to larger randomised controlled trials utilising validated patient reported outcome measures.

An Algorithmic Approach to the Management of Recurrent Lateral Patellar Dislocation

High-level evidence supports nonoperative treatment for first-time lateral acute patellar dislocations. Surgical intervention is often indicated for recurrent dislocations. Recurrent instability is often multifactorial and can be the result of a combination of coronal limb malalignment, patella alta, malrotation secondary to internal femoral or external tibial torsion, a dysplastic trochlea, or disrupted and weakened medial soft tissue, including the medial patellofemoral ligament (MPFL) and the vastus medialis obliquus. MPFL reconstruction requires precise graft placement for restoration of anatomy and minimal graft tension. MPFL reconstruction is safe to perform in skeletally immature patients and in revision surgical settings. Distal realignment procedures should be implemented in recurrent instability associated with patella alta, increased tibial tubercle-trochlear groove distances, and lateral and distal patellar chondrosis. Groove-deepening trochleoplasty for Dejour type-B and type-D dysplasia or a lateral elevation or proximal recession trochleoplasty for Dejour type-C dysplasia may be a component of the treatment algorithm; however, clinical outcome data are lacking. In addition, trochleoplasty is technically challenging and has a risk of substantial complications.

Reconstructive surgery for patellofemoral joint incongruency

PURPOSE

A retrospective analysis of a heterogeneous patient cohort was performed to determine the outcome and eligibility of a combined trochleaplasty and soft tissue-balancing technique for repair of patellofemoral joint disorders.

METHODS

A strict surgical treatment algorithm including trochleaplasty and reconstruction of the medial patellofemoral ligament and vastus medialis oblique muscle was implemented to restore the patellofemoral joint. A heterogeneous patient cohort including 46 consecutively treated symptomatic knees was reviewed. The median follow-up period was 4.7 years (range 24-109 months).

RESULTS

No patellar redislocation occurred post-operatively, and the median Kujala score improved from 62 (9-96) to 88 (47-100) points (p < 0.001) at follow-up. Radiological signs of trochlear dysplasia were corrected, and both patellar height and trochlear depth were significantly restored after surgery. In total, 16% of affected patients with pre-existing patellofemoral degenerative changes showed progression of osteoarthrosis according to the Kellgren and Lawrence classification.

CONCLUSION

The surgical combination of trochleaplasty and reconstruction of the medial patellofemoral ligament and vastus medialis oblique muscle offers excellent clinical and radiological results. The overall results of the present study showed significant improvement of the Kujala score in patients with Dejour grades C and D dysplasia. These results outline the clinical relevance of trochleaplasty with additional soft tissue balancing as an effective joint-preserving method with satisfying results in patients with pre-existing degenerative changes.

LEVEL OF EVIDENCE

IV.

Patellar instability factors in isolated medial patellofemoral ligament reconstructions--what does the literature tell us? A systematic review

BACKGROUND

Many studies have demonstrated good results after medial patellofemoral ligament (MPFL) reconstruction for patients with patellar instability. The applicability of published studies to the clinical decision-making process for the individual patient with patellar instability, however, is not well elucidated.

HYPOTHESIS

There is inconsistency in the reporting of preoperative and postoperative variables, which limits the applicability of current studies to patients with patellar instability.

STUDY DESIGN

Systematic review.

METHODS

A systematic review of the literature was conducted using the search term medial patellofemoral ligament reconstruction to identify studies with cohorts of patients with isolated MPFL reconstruction. A combination of inclusion and exclusion criteria resulted in 24 studies being reviewed for a variety of preoperative demographics, physical examination findings, and imaging findings, as well as postoperative outcomes, including redislocation and responses to subjective questionnaires.

RESULTS

A physical examination of lateral patellar translation was reported in 42% of studies, by reporting an apprehension sign (n = 9), reporting quadrant translation (n = 7), or both. For patellar instability factors on imaging, patellar height was reported as a preoperative variable in 75% of studies, and trochlear dysplasia was reported in 83% of studies. The tibial tubercle-trochlear groove distance was reported as a preoperative variable in 42% of studies. The rate of redislocation after index surgery was reported in 92% of studies. Patient-related outcome measures were reported in all of the studies; the Kujala score was the most common. A homogeneous population was selected as part of the authors' surgical indications for "isolated" MPFL in 67% of studies, and a heterogeneous population was selected in 33% of studies.

CONCLUSION

Current literature on MPFL reconstruction contains diverse methods of recording preoperative and postoperative variables. Most studies report on a homogeneous population, with inconsistent applicability to the broad spectrum of patients with patellar instability. Outcomes reporting in our current literature needs more clarity and consistency regarding reporting methodology to be of value for the treating clinician.

Robot-aided in vitro measurement of patellar stability with consideration to the influence of muscle loading

Background

Anterior knee pain is often associated with patellar maltracking and instability. However, objective measurement of patellar stability under clinical and experimental conditions is difficult, and muscular activity influences the results. In the present study, a new experimental setting for in vitro measurement of patellar stability was developed and the mediolateral force–displacement behavior of the native knee analyzed with special emphasis on patellar tilt and muscle loading.

Methods

In the new experimental setup, two established testing methods were combined: an upright knee simulator for positioning and loading of the knee specimens, and an industry robot for mediolateral patellar displacement. A minimally invasive coupling and force control mechanism enabled unconstrained motion of the patella as well as measurement of patellar motion in all six degrees of freedom via an external ultrasonic motion-tracking system. Lateral and medial patellar displacement were measured on seven fresh-frozen human knee specimens in six flexion angles with varying muscle force levels, muscle force distributions, and displacement forces.

Results

Substantial repeatability was achieved for patellar shift (ICC(3,1) = 0.67) and tilt (ICC(3,1) = 0.75). Patellar lateral and medial shift decreased slightly with increasing flexion angle. Additional measurement of patellar tilt provided interesting insights into the different displacement mechanisms in lateral and medial directions. For lateral displacement, the patella tilted in the same (lateral) direction, and tilted in the opposite direction (again laterally) for medial displacement. With regard to asymmetric muscle loading, a significant influence (p < 0.03, up to 5 mm shift and 8° tilt) was found for lateral displacement and a reasonable relationship between muscle and patellar force, whereas no effect was visible in the medial direction.

Conclusion

The developed experimental setup delivered reproducible results and was found to be an excellent testing method for the in vitro analysis of patellar stability and future investigation of surgical techniques for patellar stabilization and total knee arthroplasty. We demonstrated a significant influence of asymmetric quadriceps loading on patellar stability. In particular, increased force application on the vastus lateralis muscle led to a clear increase of lateral patellar displacement.

Prospective evaluation of anatomic patellofemoral inlay resurfacing: clinical, radiographic, and sports-related results after 24 months

PURPOSE

To prospectively evaluate the clinical, radiographic, and sports-related outcomes at 24 months after isolated and combined patellofemoral inlay resurfacing (PFIR).

METHODS

Between 2009 and 2010, 29 consecutive patients with patellofemoral osteoarthritis (OA) were treated with the HemiCAP(®) Wave Patellofemoral Resurfacing System (Arthrosurface, Franklin, MA, USA). Based on preoperative findings, patients were divided into two groups: group I, isolated PFIR (n = 20); and group II, combined PFIR with concomitant procedures to address patellofemoral instability, patellofemoral malalignment, and tibiofemoral malalignment (n = 9). Patients were evaluated preoperatively and at 24 months postoperatively. Clinical outcomes included WOMAC, subjective IKDC, Pain VAS, Tegner activity score, and a self-designed sports questionnaire. Kellgren-Lawrence grading was used to assess progression of tibiofemoral OA. The Caton-Deschamps Index was used to assess differences in patellar height.

RESULTS

Twenty-seven patients (93 %) were available for 24-month follow-up. Eighty-one per cent of the patients were either satisfied or very satisfied with the overall outcome. Significant improvements in the WOMAC, subjective IKDC, and Pain VAS were seen in the overall patient cohort and in both subgroups. The median Tegner score and sports frequency showed a significant increase in the overall patient cohort and in group II. The number of sports disciplines increased significantly in both subgroups. No significant progression of tibiofemoral OA or changes in patellar height were observed.

CONCLUSION

Patellofemoral inlay resurfacing is an effective and safe procedure in patients with symptomatic patellofemoral OA. Significant improvements in functional scores and sports activity were found after both isolated and combined procedures.

LEVEL OF EVIDENCE

Prospective case series, Level III.

MPFL reconstruction: technique and results

Patellar instability is a common problem, and medial patellofemoral ligament (MPFL) injury is inherent with traumatic patellar dislocations. Initial nonoperative management is focused on reconditioning and strengthening the dynamic stabilizers of the patella. For those patients who progress to recurrent instability, further investigation into the predisposing factors is required. MPFL reconstruction is indicated in patients with recurrent instability and insufficient medial restraint due to MPFL injury. A technique of MPFL reconstruction is outlined. This procedure may also be performed in combination with other realignment procedures.

Medial patellofemoral ligament (MPFL) reconstruction improves radiographic measures of patella alta in children

BACKGROUND

Patellofemoral instability has previously been associated with patella alta. The purpose of this study was to evaluate adolescents undergoing MPFL reconstruction for standardized indices of patellar height on pre- and post-operative radiographs to determine if these radiographic parameters change after MPFL reconstruction.

METHODS

Twenty-seven children (mean age 14.9years old) who underwent MPFL reconstruction without a distal realignment procedure were evaluated pre- and post-operatively for Insall-Salvati Ratio, Modified Insall-Salvati Ratio, and Caton-Deschamps Index by three blinded raters. Intrarater reliability and interrater reliability were calculated for each index, and means of each were compared pre- and post-operatively to determine if MPFL reconstruction was associated with improved patellar height.

RESULTS

All three indices of patellar height indicated that there was patella alta present in this cohort preoperatively. Furthermore, all three measures were significantly improved postoperatively (paired t-tests, P<0.001 for all) to within normal childhood ranges. Interrater reliability was excellent for both the Insall-Salvati Ratio (ICC=0.89) and Caton-Deschamps Index (ICC=0.78), and adequate for the Modified Insall-Salvati Ratio (ICC=0.57); intrarater reliability was excellent for all three (ICCs: 0.91, 0.82, 0.80 respectively).

CONCLUSIONS

MPFL reconstruction in children using hamstring autograft was associated with consistently improved patellar height indices to within normal childhood ranges. This associated improvement of patellar height as measured on a lateral radiograph may subsequently improve patellofemoral mechanics by drawing the patella deeper and more medially into the trochlear groove.

LEVEL OF EVIDENCE

Level 4.

Medial patellofemoral ligament reconstruction as an isolated or combined procedure for recurrent patellar instability

PURPOSE

The principal aim of this study was to report the outcomes of medial patellofemoral ligament (MPFL) reconstruction, used as either an isolated procedure or in combination with another stabilization procedure, for the primary treatment of recurrent patellar instability.

METHODS

Between 2007 and 2012, 45 patients with recurrent patellar instability and no prior stabilization surgery had an MPFL reconstruction by a single surgeon, either as an isolated procedure or in combination with another stabilization procedure. Questionnaires detailing patellar instability since surgery, knee pain, ability to negotiate stairs, and sports participation were completed, and data regarding examination and radiological findings were collected from the medical record.

RESULTS

A total of 36 (80%) patients completed the questionnaire at a mean of 3.1 years (minimum 1 year), whilst a further 11% had clinical follow-up of greater than 1 year. Four patients were excluded due to lack of adequate follow-up. Thirty-one patients had an isolated MPFL reconstruction and none had further patellar instability. Of the ten patients who had a combined procedure, one experienced recurrent instability. Return to sport rates were 81 and 57% for the isolated and combined groups, respectively, with the majority returning to strenuous sport (81 and 57%, respectively). Most patients (96 and 80%) could negotiate stairs without difficulty, whilst 38 and 40% reported some degree of anterior knee pain.

CONCLUSIONS

This study shows that satisfactory results can be obtained using MPFL reconstruction either in isolation or in combination to treat recurrent patellar instability. Whether the indications for an isolated MPFL can be extended further remains unclear.

LEVEL OF EVIDENCE

III.

Clinical outcome after medial patellofemoral ligament reconstruction and autologous chondrocyte implantation following recurrent patella dislocation

PURPOSE

Medial patellofemoral ligament (MPFL) reconstruction is a well-established treatment option in recurrent patella dislocation. The combination with associated retropatellar cartilage lesions are severe injuries and very difficult to treat. The purpose of this study was to evaluate our clinical results of MPFL reconstruction and autologous chondrocyte implantation (ACI).

METHODS

Thirteen patients with recurrent patella dislocation were treated with a combination of MPFL reconstruction and ACI at our institution between 2010 and 2014. All patients had at least 2 patella dislocations. The posttraumatic cartilage lesions were grade IV according to the ICRS and were localized retropatellar in 8 cases and at the lateral femoral condyle in 2 cases. The mean defect size was 7.2±3.5 cm2 (3-12 cm2). Subjective and objective scores were assessed before surgery and at f/u, as well as radiologic parameters and cartilage status on magnetic resonance imaging (MRI).

RESULTS

Ten patients (5 male, 5 female) with a mean follow-up of 2 years (minimum 1 year to 4 years) were enrolled in the study. At latest clinical follow-up, all patients had a stable patella with no signs of instability and all patients showed improved subjective and objective scores. Lysholm score increased to 74.1±18.7 (48-99), KOOS score to 74.4±16.9 (57-95), IKDC subjective to 63.9±22.1 (34-93) and Kujala score to 73.8±25.1 (50-100). The post-operative modified MOCART score for quality assessment of the ACI on MRI was an average of 13.7±1.8 points (11-16), with a complete fill of the defect in 80% of lesions.

CONCLUSION

Medial patellofemoral ligament reconstruction with simultaneous ACI showed good clinical results in recurrent patella dislocation with traumatic cartilage lesions grade IV. No patella re-dislocation occurred and the ACI was successful in 80% of patients according to MRI. Subjective and objective scores improved but combined surgery is inferior to reports from the literature on MPFL reconstruction alone without cartilage damage.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

Biplanar supracondylar femoral derotation osteotomy for patellofemoral malalignment: the anterior closed-wedge technique

Patellofemoral malalignment can be caused by several factors including increased internal torsion of the femur. As a causative treatment method, supracondylar femoral derotation osteotomies have been proposed. For valgus- and varus-producing supracondylar femoral osteotomies, a biplanar osteotomy has been introduced in order to enhance primary fixation stability and osseous consolidation by increased bone-to-bone contact. In this article, a modification of this technique is described, which allows for a biplanar supracondylar femoral derotation osteotomy.

LEVEL OF EVIDENCE

V.