Augmented repair of avulsion-tear type medial patellofemoral ligament injury in acute patellar dislocation

Medial-Sided Repair in Multi-Ligamentous Knee Injury

Background

Injuries to the medial structures of the knee are common in multi-ligamentous knee injuries (MLKIs), which account for 0.02% of orthopedic injuries each year. The most common medial structure involved is the superficial medial collateral ligament (sMCL) with possible additional injury to the posterior oblique ligament (POL) and deep medial collateral ligament (dMCL). There has been little evidence for the superior management of these structures regarding the use of repair or reconstruction to reproduce overall knee function. Although reconstruction may provide more valgus stability postoperatively, the use of sMCL repair over reconstruction may be superior at reestablishing native anatomic alignment and kinematic relationships of the knee while also preserving proprioception and providing similar valgus stability.

Indications

Surgical repair of medial structures is typically indicated for third-degree injuries, bony avulsions, tibial plateau fracture, intra-articular entrapment of the end of the ligament (Stener-type lesions), or anteromedial stability. They are particularly indicated in the elite athlete who presents with excessive valgus laxity due to valgus knee loading, external rotation, or combined force vectors.

Technique Description

This surgical technique video demonstrates an open, medial-sided femoral and tibial approach to repair proximal and distal medial knee structures in the setting of MLKIs using case examples of a Stener lesion and a combined sMCL, POL, and medial patellofemoral ligament tears.

Results

Repair of sMCL injuries has been reported to show favorable healing, knee stability, and function.

Discussion/Conclusion

The use of fixation of the sMCL to its anatomical attachment points offers similar valgus stability and improved functional and patient-reported outcomes when compared with sMCL reconstruction.

Patient Consent Disclosure Statement

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

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

Purpose

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.

Methods

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).

Results

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.

Conclusion

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 of Evidence

Level IV, systematic review of Level I-IV.

MPFL repair after acute first-time patellar dislocation results in lower redislocation rates and less knee pain compared to rehabilitation: a systematic review and meta-analysis

PURPOSE

This study aimed to explore the efficacy of medial patellofemoral ligament (MPFL) repair versus nonoperative rehabilitation treatment on the rate of patellar redislocation and functional outcomes in skeletally mature patients with traumatic, first-time patellar dislocations.

MATERIALS AND METHODS

MEDLINE, PubMed and EMBASE were searched from database inception to May 2022 for studies examining the management options for acute first-time patellar dislocations. This study was conducted in accordance with PRISMA and R-AMSTAR guidelines. Data on redislocation rates, functional outcomes including the Kujala score for anterior knee pain, and complication rates were extracted. A meta-analysis was used to pool the mean postoperative Kujala score and calculate the proportion of patients sustaining redislocations using a random effects model. Quality assessment of included studies was performed for all included studies using the MINORS and Detsky scores.

RESULTS

This review included a total of 25 studies and 1,361 patients. The pooled mean redislocation rate in 15 studies comprising 798 patients in the rehabilitation group was 30% (95% CI 25-36%, I² = 65%). Moreover, the pooled mean redislocation rate in 10 studies comprising 170 patients undergoing MPFL repair was 7% (95% CI 3-12%, I² = 30%). The pooled mean postoperative Kujala score in 8 studies comprising 396 patients in the rehabilitation group was 82.5 (95% CI 78.3-86.8, I² = 91%), compared to a score of 88 (95% CI 87-90, I² = 76%) in 3 studies comprising 94 patients in the repair group. Range of motion deficits was reported in 3.8% of 893 patients in the rehabilitation group and 2.0% of 205 patients in the repair group.

CONCLUSION

MPFL repair resulted in a lower rate of redislocation, less knee pain, and noninferiority with respect to a range of motion deficits compared to nonoperative treatment for the management of acute first-time patellar dislocations.

LEVEL OF EVIDENCE

IV.

Femoral articular geometry and patellofemoral stability

BACKGROUND

Patellofemoral instability is a major cause of anterior knee pain. The aim of this study was to examine how the medial and lateral stability of the patellofemoral joint in the normal knee changes with knee flexion and measure its relationship to differences in femoral trochlear geometry.

METHODS

Twelve fresh-frozen cadaveric knees were used. Five components of the quadriceps and the iliotibial band were loaded physiologically with 175N and 30N, respectively. The force required to displace the patella 10mm laterally and medially at 0°, 20°, 30°, 60° and 90° knee flexion was measured. Patellofemoral contact points at these knee flexion angles were marked. The trochlea cartilage geometry at these flexion angles was visualized by Computed Tomography imaging of the femora in air with no overlying tissue. The sulcus, medial and lateral facet angles were measured. The facet angles were measured relative to the posterior condylar datum.

RESULTS

The lateral facet slope decreased progressively with flexion from 23°±3° (mean±S.D.) at 0° to 17±5° at 90°. While the medial facet angle increased progressively from 8°±8° to 36°±9° between 0° and 90°. Patellar lateral stability varied from 96±22N at 0°, to 77±23N at 20°, then to 101±27N at 90° knee flexion. Medial stability varied from 74±20N at 0° to 170±21N at 90°. There were significant correlations between the sulcus angle and the medial facet angle with medial stability (r=0.78, p<0.0001).

CONCLUSIONS

These results provide objective evidence relating the changes of femoral profile geometry with knee flexion to patellofemoral stability.

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.

Surgical versus conservative management of acute patellar dislocation in children and adolescents: a systematic review

PURPOSE

The goal of this study was to perform a comparative review to determine whether there is a significant difference in the rate of repeat dislocation and clinical outcome between surgical and conservative management of acute patellar dislocation in children and adolescents.

METHODS

A systematic review of the MEDLINE database was performed. English-language clinical outcome studies with a primary outcome/treatment specific to acute patella dislocation in a paediatric population were included. Eleven studies met inclusion criteria; Chi-square analysis, independent t tests and weighted mean pooled cohort statistics were performed where appropriate.

RESULTS

A total of 470 conservatively managed and 157 operatively treated knees were included. Conservatively managed patients were on average 17.0 years and had a mean follow-up of 3.9 years; surgically managed patients were on average 16.1 years and had a mean follow-up of 4.7 years. Conservatively managed knees had a 31% rate of recurrent dislocation rate compared to 22% in surgical knees (p = 0.04). Trochlear dysplasia and skeletal immaturity confer greater risk for recurrent instability. Surgical treatment may provide clinically important quality of life and sporting benefit.

CONCLUSIONS

Surgical treatment of first time patella dislocation in children and adolescents is associated with a lower risk of recurrent dislocation and higher health-related quality of life and sporting function. There is a paucity of evidence on MPFL reconstruction for first time traumatic patella dislocation in this population.

LEVEL OF EVIDENCE

IV.

Minimally invasive medial patellofemoral ligament reconstruction for patellar instability using an artificial ligament: A two year follow-up

BACKGROUND

Recurrence of acute patellar dislocation affects approximately 30% of individuals, and up to 75% of those with grade IV instability. The medial patellofemoral ligament (MPFL) is considered to be critical for patellar stabilization. MPFL reconstruction with allografts has been proposed to reduce risk of recurrence, but there is limited evidence about the safety and effectiveness of techniques using synthetic allografts.

METHODS

We present a retrospective case series of 29 individuals who underwent a MPFL reconstruction between 2009 and 2012, using an artificial ligament for patellar instability by a single surgeon. Clinical, radiological and functional outcomes were measured at a minimum of 24 months.

RESULTS

31 knees (29 individuals) were followed up for a median of 43 (range: 24-68) months. Using the Crosby and Insall grading system, 21 (68%) were graded as excellent, nine (29%) were good, one (3%) as fair and none as worse at 24 months. The mean improvement in Lysholm knee score for knee instability was 68 points (standard deviation 10). Ligamentous laxity was seen in 17 (55%) of individuals. In this subset, 12 were graded as excellent, four as good and one as fair. The mean improvement in patellar height was 11% at three months follow-up. All knees had a stable graft fixation with one re-dislocation following trauma.

CONCLUSIONS

We propose a minimally invasive technique to reconstruct the MPFL using an artificial ligament allowing early mobilization without bracing. This study indicates the procedure is safe, with a low risk of re-dislocation in all grades of instability.

LEVEL OF EVIDENCE

Level IV Case Series.

Evaluation of medial patellofemoral ligament tears after acute lateral patellar dislocation: comparison of high-frequency ultrasound and MR

OBJECTIVES

The purpose of this study was to compare the diagnostic performance of high-frequency ultrasound with MR in the evaluation of medial patellofemoral ligament (MPFL) lesions after acute lateral patellar dislocation (LPD).

METHODS

High-frequency ultrasound and MR images were prospectively obtained in 97 consecutive patients with acute LPD. Images were acquired using standardised protocols and were independently evaluated by two radiologists. The MPFL was assessed at three sites (patellar insertion, femoral attachment, and mid-substance) for signs of injury.

RESULTS

Of a total of 291 sites in 97 MPFLs, 127 showed proven MPFL tear at surgery, including 51 sites of complete tear and 76 sites of partial tear. In a site-based analysis, the sensitivity, specificity, and accuracy of high-frequency ultrasound was 90.8%, 96.3%, and 94.6%, respectively, for partial MPFL tear and 86.3%, 96.3%, and 94%, respectively, for complete tear. For MR, the sensitivity, specificity, and accuracy was 81.6%, 95.7%, and 91.3%, respectively, for partial MPFL tear and 80.4%, 95.7%, and 92.1%, respectively, for complete tear. There was no statistical difference between high-frequency ultrasound and MR in the assessment of partial (P = 0.1, 0.777, 0.155) or complete (P = 0.425, 0.777, 0.449) MPFL lesions. Interobserver agreement was very good for high-frequency ultrasound and good for MR.

CONCLUSIONS

Data suggest that high-frequency ultrasound and MR have similar diagnostic performance in the evaluation of MPFL lesions after acute LPD.

KEY POINTS

• High-frequency ultrasound and MR were able to detect MPFL lesions after acute lateral patellar dislocation. • High-frequency ultrasound and MR showed similarly high accuracy in diagnosing MPFL lesions. • Interobserver agreement was very good for high-frequency ultrasound and good for MR.

Reconstruction of the medial patellofemoral ligament using hamstring tendon graft with different methods: a biomechanical study

OBJECTIVE

To measure the tensile strength of the normal medial patellofemoral ligament (MPFL), and evaluate the biomechanics of different fixation methods of the hamstring tendon graft on the patella.

METHODS

Eight fresh cadaver knees were prepared by isolating the patella, leaving only the MPFL as its attachment to the medial condyle of femur. The MPFL was reconstructed by three different methods: four-suture fixation, anchors-single suture fixation, and anchors-double suture fixation. The tensile strength and the elongation of the normal MPFL and the tendon grafts were measured.

RESULTS

The tensile strength of the four-suture fixation group (234.86±49.02 N) was stronger than that of the normal MPFL (146.91±25.30 N, P=0.0014) and the anchors-single suture group (159.17±49.07 N, P=0.0077), while weaker than that of the anchors-double suture group (314.74±78.46 N, P=0.0052) CONCLUSIONS: With regard to the tensile strength, the four-suture fixation method is reliable for clinical use. Compared with the anchor-suture method, the four-suture fixation method which has no specific implants is more economical, convenient and efficient.

Sonography on injury of the medial patellofemoral ligament after acute traumatic lateral patellar dislocation: Injury patterns and correlation analysis with injury of articular cartilage of the inferomedial patella

OBJECTIVE

The purpose of this study was to investigate the accuracy of high-frequency ultrasonography in the diagnosis of injuries of medial patellofemoral ligaments (MPFLs), analyse the characteristics of MPFL injury and correlations between injury of the MPFL and articular cartilage of the inferomedial patella in patients with acute traumatic lateral patellar dislocation.

METHODS

High-frequency sonographic images of 49 patients with acute traumatic lateral patellar dislocations treated surgically were reviewed. The χ(2) tests were performed for statistical analysis.

RESULTS

Twenty-eight cases of complete MPFL tear and 21 cases of partial MPFL tear were identified in operation, with 27 cases of MPFL tear located at their femoral attachment, 21 cases of tear at the patellar attachment and one case of midsubstance tear. The diagnostic accuracy of sonography regarding partial MPFL tear and complete MPFL tear was 89.8% and 89.8%. Among the patients with MPFL tear at the patellar attachment, eight and six cases were concomitant with chondral and osteochondral lesions in the inferomedial patella, respectively, in contrast to nine and six cases in patients with MPFL tear at the femoral attachment, respectively. There was no significant difference between the two locations described above regarding the prevalence rates of chondral or osteochondral lesions of the inferomedial patella (P=0.732, P=0.614). Among the patients with complete MPFL tear, 12 and 10 cases were concomitant with chondral and osteochondral lesions in the inferomedial patella, respectively, while six and two cases were concomitant with partial MPFL tear. There was no significant difference between the two types of injuries discussed above on the prevalence rates of chondral lesions of the inferomedial patella (P=0.305), but the prevalence rate of osteochondral lesions between the two types of injuries discussed above was statistically different (P=0.035).

CONCLUSIONS

The MPFL is most easily injured at the femoral attachment, secondly at the patellar attachment. High-frequency ultrasonography is an accurate method in the diagnosis of an MPFL tear. There are neither significant differences on the prevalence rates of chondral or osteochondral lesions of the inferomedial patella between locations of MPFL injuries, nor significant difference on the prevalence rates of chondral lesions between MPFL injury types; but the complete MPFL tear is more often concomitant with inferomedial patellar osteochondral lesions than the partial MPFL tear.

The anatomy of the medial patellofemoral ligament

BACKGROUND

Fibrous connections and fibrofatty tissue between the layers of the medial retinaculum have prevented accurate definition of the true anatomy of the medial patellofemoral ligament. This has led to confusion about the origin, form, course, and insertion of this structure.

HYPOTHESIS

The medial patellofemoral ligament is a discrete structure that can be approached, isolated, and definitively described.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Fifty fresh or fresh-frozen human knee specimens were carefully dissected to determine the precise anatomy of the medial patellofemoral ligament.

RESULTS

Present in all specimens, the medial patellofemoral ligament was found to have 2 origins: (1) a transverse 10.6-mm origin from the bony groove between the medial epicondyle and the adductor tubercle, and (2) an oblique decussation originating from the proximal 30 mm of the leading edge of the superficial medial collateral ligament. The 2 origins combined and inseparably joined the vastus medialis obliquus tendon and inserted securely into the ventral edge of the bony patella over a span of 28.2 + or - 5.6 mm adjacent to the articular surface of the patella. The length from the femoral origin to the patella was 59.8 + or - 4.8 mm. The key to the dissection was finding the fine capsular vessels from the descending genicular artery that is between layers I and II of the medial retinacular structures.

CONCLUSION

The medial patellofemoral ligament is a constant structure in ladouble daggeryer II, with a complex anatomy that can be defined by careful dissection using the capsular branches of the descending genicular artery as a guide.

CLINICAL RELEVANCE

This study provides essential new information that could help surgeons safely locate the medial patellofemoral ligament and repair or reconstruct it anatomically.

Conservative versus surgical treatment for repair of the medial patellofemoral ligament in acute dislocations of the patella

PURPOSE

The objective of this study was to analyze and compare the results obtained after 2 types of treatment, surgical and conservative, for acute patellar dislocations.

METHODS

We divided 33 patients with acute patellar dislocations into 2 groups. One group with 16 patients underwent conservative treatment (immobilization and subsequent physiotherapy), and the other group with 17 patients underwent surgical treatment. A radiographic examination was performed in the evaluation of the patients to verify predisposing factors for patellofemoral instability, and the Kujala questionnaire was applied with the intention of analyzing the improvement of pain and quality of life. The chi(2) test, t test, and Fisher test were used in the statistical evaluation. A significance level of P < .05 was adopted.

RESULTS

The groups were considered parametric in relation to age and sex. The conservative treatment group exhibited a higher number of recurrent dislocations (8 patients) than the surgical treatment group, which did not have any relapses. In addition, the surgical treatment group obtained a better mean score on the Kujala test (92) than the conservative treatment group (69).

CONCLUSIONS

We conclude that surgical treatment afforded better results. There were no recurrences in the surgical treatment group, but there were 8 recurrences in the conservative treatment group. The mean Kujala score was 92 in the surgical treatment group and 69 in the conservative treatment group.

LEVEL OF EVIDENCE

Level II, lesser-quality therapeutic randomized controlled trial.

Ligament reconstruction versus distal realignment for patellar dislocation

Recently, medial patellofemoral ligament reconstruction has been emphasized for the treatment of patellar dislocation. This study compared the results of medial patellofemoral ligament reconstruction by adductor magnus tenodesis with distal patellar realignment in patients with recurrent patellar dislocation. Additionally, the development of patellofemoral osteoarthrosis was compared for these two procedures at a median 10-year followup. Between 1994 and 2000, 47 consecutive patients were treated for recurrent patellar dislocation by adductor magnus tenodesis (18 knees) or Roux-Goldthwait procedure (29 knees). Redislocations, subjective symptoms, and functional outcomes were evaluated. Magnetic resonance imaging was performed at followup. The incidence of patellar redislocation after surgery was 7% in the adductor magnus group and 14% in the Roux-Goldthwait group. Median Kujala scores were 88 for the adductor magnus group and 86 for the Roux-Goldthwait group. Magnetic resonance imaging revealed patellofemoral articular cartilage lesions in 22 knees (73.3%) at followup, including 14 (46.6%) with full-thickness cartilage loss. Radiographs revealed patellofemoral osteoarthritis in five patients in the Roux-Goldthwait group and in none of the patients in the adductor magnus group. Adductor magnus tenodesis is a reliable method to treat recurrent patellar dislocation. The medial patellofemoral ligament reconstruction seems to reduce the risk of osteoarthrosis compared with distal realignment surgery.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Current concepts review: the medial patellofemoral ligament

Awareness of the medial patellofemoral ligament has increased markedly over the past decade. Previously, this structure, which was delineated in anatomical studies, had been little recognized and underestimated with regard to its importance in stabilizing the patella. The goal of this review of the medial patellofemoral ligament is to develop a current understanding of how this ligament functions in patellofemoral stability and to review the current treatment options for medial patellofemoral ligament disruption.

First-time traumatic patellar dislocation: a systematic review

Acute patellar dislocations can result in patellar instability, pain, recurrent dislocations, decreased level of sporting activity, and patellofemoral arthritis. The initial management of a first-time traumatic patellar dislocation is controversial with no evidence-based consensus to guide decision making. Most first-time traumatic patellar dislocations have been traditionally treated nonoperatively; however, there has been a recent trend in initial surgical management. We performed a systematic review of Level I-IV studies to make evidence-based medicine recommendations on how a clinician should approach the diagnosis and treatment of a first-time traumatic dislocation. More specifically we answer the primary question of when initial treatment should consist of operative versus closed management. Based on the review of 70 articles looking at study design, mean followup, subjective and validated outcome measures, redislocation rates, and long-term symptoms, we recommend initial nonoperative management of a first-time traumatic dislocation except in several specific circumstances. These include the presence of an osteochondral fracture, substantial disruption of the medial patellar stabilizers, a laterally subluxated patella with normal alignment of the contralateral knee, or a second dislocation, or in patients not improving with appropriate rehabilitation.

Medial patellofemoral ligament reconstruction: a novel technique using the patellar ligament

In patients with chronic patellofemoral instability, more than 2 episodes of dislocation, and an anterior tuberosity trochlear groove of less than 20 mm as measured on computed tomography or nuclear magnetic resonance imaging, we have developed a technique for medial patellofemoral ligament reconstruction that uses a medial strip of the patellar ligament (PL). The incision started proximally at the level of the superior margin of the patella, centrally between the patellar medial margin and the medial epicondyle. A descending incision was then made, directed toward the superomedial margin of the tibial tubercle. We performed a plane-by-plane dissection up to the peritenon of the PL. With an osteotome, we could remove a 2-cm bone fragment concerning the medial third of the distal insertion of the PL or keep the distal end free. Using a No. 11 scalpel blade, we carefully detached the PL from the patella up to the transition between the proximal third and medial third of the patella. We placed the stitches between the periosteum and the ligament using FiberWire absorbable threads (Arthrex, Naples, FL) to safely rotate the graft. After that, we dissected the medial capsule and approached the femoral medial epicondyle. Then we placed a Krackow suture in the free tendon end using absorbable threads or anchored the threads into 2 holes that were previously drilled, and we secured the end with an absorbable interference screw or anchors. The fixation should be performed with the knee at 15 degrees to 30 degrees of flexion. Then we sutured the distal edge of the vastus medialis muscle to the graft, which bestows a dynamic component upon the reconstruction, and we immobilized the knee with a removable brace.