Medial Patellofemoral Ligament Reconstruction in the Pediatric Population: Skeletal Immaturity Does Not Affect Functional Outcomes but Demonstrates Increased Rate of Subsequent Knee Injury

Evaluating the Outcomes of Trochleoplasty in the Treatment of Patellofemoral Instability in the Adolescent and Young Adult Knee With Severe Trochlear Dysplasia: A Minimum 2-Year Follow-up

Background

Recurrent patellofemoral joint instability in adolescent and young adult patients is associated with several anatomic risk factors. A lack of consensus exists as to which risk factor(s) should be addressed at the time of surgery, but the presence of a severely dysplastic femoral trochlea has been described as an indication for surgical intervention. Furthermore, literature has suggested that a severely dysplastic trochlea can be a contributing factor to a failed medial patellofemoral ligament reconstruction (MPFLR) alone.

Purpose

To investigate the postoperative outcomes of patients <20 years of age who underwent primary trochleoplasty in combination with MPFLR and lateral retinacular lengthening (LRL), with some receiving concomitant tibial tubercle osteotomy (TTO).

Study Design

Cohort study; Level of evidence, 3.

Methods

A retrospective review of prospectively collected data performed in patients <20 years old who underwent trochleoplasty with MPFLR with ≥2 years of follow-up. Demographics, concomitant procedures, patient-reported outcome (PRO) measures, magnetic resonance imaging, and radiographs were reviewed. Patients who also underwent TTO were compared with those who did not.

Results

A total of 21 knees from 15 patients (11 female, 4 male) with mean age of 16.4 years (13.7-19.8 years) were included. All patients had severe trochlear dysplasia and were treated with trochleoplasty, MPFLR, and LRL. Ten knees underwent additional TTO and were compared with those who did not (n = 11). The Pediatric International Knee Documentation Committee, Kujala, and Lysholm scores collected at a mean of 3.3 years (range, 2-6 years) postoperatively did not differ significantly between groups. There were no patient-reported postoperative episodes of patellar instability by the final follow-up.

Conclusion

At a minimum 2-year follow-up, there were no statistically significant differences observed in PROs between patients who underwent trochleoplasty and concomitant TTO and those who had trochleoplasty alone, with neither group having any reported episodes of postoperative patellar instability. Furthermore, at final follow-up favorable PROs were achieved in patients who underwent trochleoplasty for the treatment of their patellofemoral instability with severe trochlear dysplasia.

Physeal-Sparing Soft Tissue Realignment in Pediatric Patellofemoral Instability Patients: A Review of Treatment Options and Outcomes

Patellofemoral instability is a common condition in children, with an annual incidence of approximately 50 cases per 100,000 children. Instability of the patella involves a number of structures, such as the medial patellofemoral ligament and the vastus medialis obliquus, which can be used for patellar realignment in soft tissue, physeal-sparing procedures. In this rapid review, we aim to review the surgical interventions, post-operative outcomes, and associated surgical complications of global soft tissue procedures in the management of patellofemoral instability. A search of the Medline database was conducted to identify studies evaluating the treatment and outcomes of global treatment of pediatric patellofemoral instability. The included studies analyzed the surgical management of patellofemoral instability in pediatric patients, utilizing soft tissue global procedures and reported functional outcomes, return to sport or play, and post-operative complications. A total of eight studies were included, comprising a cohort of 270 pediatric and adolescent patients and 334 knees. The average patient age was 10.6 years, with 60.4% (163/270) patients being female, and the mean follow-up duration was 58.4 months. Of the eight studies, two examined the three-in-one procedure, three examined the four-in-one procedure, one examined a combination of medial and lateral release, and two examined the Galeazzi procedure. This review underscores the variety of global physeal-sparing surgical procedures available for treating patellofemoral instability. While outcomes are generally favorable, with high rates of return to sport, recurrent residual instability and recurrent dislocation remain significant challenges, with residual instability affecting nearly half of patients. Future research should focus on exploring long-term outcomes, optimizing patient selection, and identifying the causes of recurrent instability to further enhance patient outcomes and reduce complication rates.

Medial Patellofemoral Ligament Repair with Suture Tape Augmentation Can Yield Good Midterm Clinical Outcomes Regardless of Skeletal Maturity and Joint Laxity

While several studies have reported short-term clinical outcomes after medial patellofemoral ligament (MPFL) repair with suture tape augmentation, there is still a dearth of knowledge regarding midterm clinical outcomes. This study aimed to evaluate the midterm clinical outcomes of MPFL repair with suture tape augmentation in patients with patellar dislocation. We retrospectively reviewed the clinical records of patients who underwent MPFL repair with suture tape augmentation for at least one episode of patellar dislocation between 2015 and 2020. Patient-reported clinical outcomes (PROs) were evaluated via the International Knee Documentation Committee (IKDC) score and the knee injury osteoarthritis outcome score (KOOS). In total, 17 knees (4 males and 13 females) who underwent MPFL repair with suture tape augmentation with a mean follow-up of 54.6 ± 19.5 months were included in this study. PROs significantly improved from preoperatively to the final follow-up (IKDC score: 50.7 ± 26.6 vs. 88.8 ± 13.0, p < 0.001; KOOS: 68.8 ± 23.3 vs. 91.2 ± 8.4, p = 0.011) without reducing the patient's activity level at the final follow-up (UCLA AS score: 7.9 ± 2.4 at preinjury vs. 7.9 ± 2.2 at the final follow-up, p = 0.655). Subgroup analysis revealed good postoperative outcomes, regardless of the patient's skeletal maturity or the presence or absence of generalized laxity. In conclusion, MPFL repair with suture tape augmentation is a safe and effective treatment for midterm follow-up.

MPFL Reconstruction in Skeletally Immature Patients: Comparison Between Anatomic and Non-Anatomic Femoral Fixation-Systematic Review

BACKGROUND

MPFL reconstruction in children with open physis may be challenging, as a major concern during the surgery is to preserve the distal femoral physis. The purpose of this study was to compare the complication rate and the patient-reported outcomes in skeletally immature patients who underwent MPFL reconstruction using an anatomic (A) or non- anatomic (NA) surgical technique.

METHODS

For this systematic review, the authors adhered to the PRISMA guidelines. The literature search was conducted from inception to 31 May 2024. Three databases were used: Pubmed, Scopus and Cochrane library. We included skeletally immature patients who underwent MPFL reconstruction for chronic or recurrent patellar instability. The included studies should describe the surgical technique, report clinical outcomes and complications. Patients with closed physis, prior ipsilateral knee surgery, concomitant surgical procedures except for lateral retinacular release, multiligament knee injury, congenital or acute patellofemoral instability, hyperlaxity or less than 12 months follow up were excluded. Risk of bias was assessed using ROBINS-I, MINORS and MCMS scores.

RESULTS

Data from 304 procedures were collected, of which 208 were performed using an anatomic technique and 96 using a non-anatomic technique. Patient age at the time of surgery ranged from 8 to 17 years. The follow-up time ranged between 12 and 116.4 months. Postoperative Kujala (-0.73, p = 0.55) and Tegner (-0.70, p = 0.80) scores were better in the anatomic group compared to the non-anatomic one. Higher rates of recurrent instability (OR 0.91; 95%CI 0.44-1.86, p = 0.85), redislocation (OR 1.21; 95%CI 0.42-3.51, p = 0.8), subluxation (OR 0.73; 95%CI 0.29-1.83, p = 0.62), a positive apprehension test (OR 0.92; 95%CI 0.27-3.13, p = 0.89), stiffness (decreased ROM) (OR 1.63; 95%CI 0.33-1.72, p = 0.54) and reoperation (OR 1.16; 95%CI 0.35-3.80, p = 0.8) were reported in papers using the anatomic technique.

CONCLUSIONS

The findings of this systematic review reveal that there is no significant difference between anatomic and non-anatomic MPFL reconstruction techniques in terms of patient-reported outcomes and complications. Thus, the choice of surgical technique might be left up to surgeon's preference. Further high-quality, pediatric-oriented studies with long-term follow-up are needed to better guide clinical decision-making.

Management of patellar instability in skeletally immature patients

Surgical intervention is the treatment of choice for recurrent lateral patellar instability. Surgery should be considered for first time lateral patella dislocations with osteochondral fractures or underlying anatomical risk factors. Primary repair and nonanatomical imbrications/reconstructions have fallen out of favor due to abnormal biomechanics and high rates of recurrence. Anatomical reconstruction of the MPFL using a variety of auto and allograft tissues have yielded good outcomes and low redislocation rates. Physeal sparing MPFL reconstruction techniques under radiological control are safe and do not cause growth disturbance. Allografts may be indicated for hyperlax patients. Although no clear cutoff points exist, correction of valgus and excessive femoral anteversion should be considered when indicated. Osteochondral and chondral injuries are common and should be addressed during surgery for instability.