Surgical Options for Patellar Stabilization in the Skeletally Immature Patient

Medial Patellofemoral Ligament Reconstruction in Skeletally Immature Patients: A Systematic Review of Outcomes by Fixation Technique

Background

Various medial patellofemoral ligament (MPFL) reconstruction techniques have been developed to minimize risks to the physis in skeletally immature patients.

Purpose

To examine outcomes of MPFL reconstruction (MPFLR) based on fixation technique in skeletally immature patients.

Study Design

Systematic review; Level of evidence, 4.

Methods

PubMed, Scopus, Ovid, Cochrane Library, and CINAHL databases were searched for the literature on outcomes of MPFLR in the pediatric population, utilizing various anatomic and nonanatomic techniques. Primary outcomes were postoperative redislocation rates, return-to-sports (RTS) rates, and patient-reported outcomes (PROs). Moreover, outcomes involving sequela of growth plate disturbance were collected.

Results

The final analysis included 17 studies-2 using sling-based techniques, 3 using surface-based techniques, 5 using soft tissue realignments, and 7 utilizing transosseous femoral fixations. Higher rates of postoperative redislocation were found in the sling-based (14.8%) and distal soft tissue realignment using semitendinosus tenodesis (38%) techniques, while lower rates were noted with surface-based (1.3%) and transosseous (3.4%) techniques. For PROs, there were large amounts of heterogeneity among studies, but all reported postoperative improvements, with more positive PROs generally seen in anatomic reconstructions. The RTS rate was 100% for surface-based techniques, 79.4% for distal soft tissue realignments, 79.5% for soft tissue realignment techniques, and 83.2% for transosseous techniques. No negative outcomes as a sequela of growth plate disturbance were reported.

Conclusion

Nonanatomic techniques-such as sling-based and distal soft tissue realignment techniques-have higher rates of redislocation and lower RTS rates in skeletally immature patients undergoing MPFLR. Surface-based and transosseous tunnel-based techniques were shown to have lower redislocation and higher RTS rates.

Clinical Relevance

This review provides insight into the most appropriate surgical management of patellar instability in patients with open growth plates.

What's up with patella alta?

PURPOSE OF REVIEW

Patella alta, which describes an abnormally proximally positioned patella, has become of particular interest as it has been identified as a potential factor in patellofemoral instability (PFI) and other common pediatric orthopedic conditions. The purpose of this review is to describe the condition, measuring techniques, and its association with pediatric orthopedic conditions, and to evaluate methods of correction of patella alta.

RECENT FINDINGS

Recent literature has explored the etiology of patella alta by investigating patellar height as age increases, with inconclusive findings as to whether the condition is congenital or acquired over time. Additionally, patella alta has been identified to be associated with several pediatric orthopedic conditions, including PFI, anterior knee pain, and cerebral palsy. As such, methods of correction for patella alta, including medial patellofemoral ligament reconstruction (MPFLR), tibial tubercle distalization, and patella tendon imbrication, have been studied.

SUMMARY

Patella alta, defined by an abnormally high patellar height, is associated with patellofemoral instability, anterior knee pain, and cerebral palsy. Various indices have been developed to measure and define patellar height, including the Caton-Deschamps Index and Koshino-Sugimoto Index which are applicable to a pediatric population. Treatments include isolated or concomitant MPFLR, distalizing tibial tubercle osteotomy, and patella tendon imbrication, which have shown success in reducing patellar height and improving patella alta, though risks for complications do exist.

Patellofemoral instability part 2 (Bony procedure for patellar surgical stabilization): State of the art

Surgery for patellofemoral instability is usually considered in patients with recurrent patellar dislocation and after a first-time patellar dislocation in the presence of either an associated osteochondral fracture or high risk of recurrence due to the presence of several risk factors. Risk factors include demographics such as age, contralateral dislocation, as well as anatomic risk factors (ARF) such as abnormal coronal and rotational alignment, trochlear dysplasia, lateral quadriceps vector, and patella alta. Surgery with soft tissue procedures includes restoring the medial patellar restraints and balancing the lateral side of the joint, which can be successful in most patients. However, patients that have excessive and/or several ARFs have a high risk of failure with isolated soft tissue stabilization procedures; associated surgical correction of select ARFs is recommended. This article will discuss an approach to evaluate the risk-benefit of adding bony procedures which may decrease the chances of recurrence of patellar instability but can increase surgery-related complications. Approaching patellofemoral instability in a patient-specific approach and combining corrective osteotomies and trochleoplasties with a shared decision with the patient/family, guides surgeons to deliver optimal care for the patellar instability patient.

Reconstruction of medial patellofemoral ligament with adductor magnus tendon for recurrent patellar dislocation in children: a retrospective comparative cohort study

BACKGROUND

The purpose of current retrospective study was to explore the outcomes of using the adductor magnus tendon to reconstruct the medial patellofemoral ligament in the treatment of recurrent patellar dislocation in children.

METHOD

Thirty-two children with recurrent patellar dislocation were selected. Sixteen cases in the conservative group, seven males and nine females, with an average age of 11.81 ± 1.28 years; sixteen cases in the surgical group, eight males and eight females, with an average age of 11.56 ± 1.15 years. All patients had no surgery history. The IS index (> 1.2), Q angle (> 20°) and tibial tubercle-femoral trochlear groove (TT-TG) distance (> 20 mm) were measured by X-ray and MRI. The conservative group was treated with closed reduction and a brace, and the surgical group received surgical treatment. Two years after surgery, congruence angle (CA) (- 6° to 6°) and lateral patellofemoral angle (LPFA) (7.7°-18.7°) were measured by X-ray image and all children were evaluated based on Kujala and Lysholm scores. The re-dislocation rate was recorded. Analysis was performed by t test and chi-square with the statistical SPSS software. P < 0.05 was considered a statistically significant difference. Furthermore, we measured the length (mm) of the adductor tendon and MPFL in three knee cadaveric specimens, and also observed the positional relationship between the two structures.

RESULT

There were no significant differences in sex, age, injury site between groups (P > 0.05). Patients in the two groups were followed up for 2 years in average. Among the 16 cases in the conservative group, 7 cases (43.75%) had recurrence of patellar dislocation, while none of recurrence in the surgical group (P < 0.05). The Lysholm score of the surgical group (94.63 ± 8.99) was significantly better than that of the conservative group (79.31 ± 18.90), and the Kujala score of the surgery group (95.25 ± 10.32) was also significantly better than that of the conservative group (77.06° ± 14.34°) (P < 0.05). The CA and LPFA of the two groups of patients after treatment were significantly recovered. The CA (- 5.81° ± 7.90°) in the surgical group was significantly better than that in the conservative group (20.94° ± 8.21°), and the LPFA (6.44° ± 3.22°) was also significantly better than that in the conservative group (- 9.18 ± 11.08), and the difference is statistically significant (P < 0.05). We found it through autopsy that adductor magnus tendon was 124.33 ± 1.53 mm long, MPFL was 48.67 ± 2.08 mm, and the femoral insertion of the adductor magnus tendon was adjacent to the MPFL femoral insertion.

CONCLUSION

Reconstruction of Medial patellofemoral ligament with the adductor magnus tendon, fixing with PEEK suture anchors on the patellar side, can achieve satisfactory results in the treatment of children with recurrent patellar dislocation. Compared with conservative treatment, the rate of recurrence is lower and the stability of the patella is better.

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

PURPOSE

To compare postoperative complication rates between patients who underwent medial patellofemoral ligament reconstruction (MPFLR) and those who underwent MPFLR with tibial tubercle osteotomy (TTO) in a large-scale study. A secondary goal was to investigate demographic associations with outcomes.

METHODS

Patients who underwent MPFLR (n = 3,480) or MPFLR-TTO (n = 615) for patellar instability were identified in the PearlDiver database. Rates of surgery for infection, procedures for knee stiffness, patellar fracture, and revision MPFLR within 2 years postoperatively were compared using multivariable logistic regression. Demographic associations with outcomes were also investigated.

RESULTS

The MPFLR-TTO cohort exhibited a significantly lower rate of revision surgery at 2 years (0.8% vs 1.9%; odds ratio [OR], 0.33; 95% confidence interval [CI], 0.10-0.80; P = .036) when compared with the MPFLR group. Independent of index procedure, patients younger than 21 years had significantly lower rates of requiring procedures for knee stiffness (OR, 0.35; 95% CI, 0.22-0.54; P < .001) and any complication at 2 years (OR, 0.59; 95% CI, 0.45-0.78; P < .001) when compared with older patients. Male patients displayed a significantly lower rate of requiring procedures for knee stiffness at 2 years than female patients (OR, 0.46; 95% CI, 0.25-0.78; P = .007). Tobacco use was associated with a significantly higher rate of postoperative infection at 2 years (OR, 2.35; 95% CI, 1.00-5.38; P = .046).

CONCLUSIONS

The MPFLR cohort exhibited higher rates of revision surgery at 2 years compared with the MPFLR-TTO cohort. Patient age under 21 years was associated with lower rates of any complication and requiring procedures for knee stiffness, male sex was associated with a lower rate of requiring procedures for knee stiffness, and tobacco use was associated with a higher rate of surgery for postoperative infection. This information can assist surgeons when counseling patients before these procedures are performed.

LEVEL OF EVIDENCE

Level III, retrospective, comparative prognostic trial.

Bisect offset ratio and cartilaginous sulcus angle are good combined predictors of recurrent patellar dislocation in children and adolescents

OBJECTIVES

Recurrent patellar dislocation (RPD) is found most commonly in the juvenile population. While risk factors have been well-established in adults, there remains a paucity in radiographical data to define normal and pathoanatomical juvenile cohorts. The objectives of this paper were to elucidate the differences in the patellofemoral joint between RPD and typically developed (TD) juvenile populations, using MRI measurements, and determine the best independent and combined predictors of RPD.

METHODS

A prospective, cross-sectional study was conducted with 25 RPD and 24 TD participants aged between 8 and 19 years. MR images were obtained to assess common measures of lower limb alignment, patellofemoral alignment, and trochlear dysplasia.

RESULTS

Significant differences were evident for acetabular inclination, tibial-femoral torsion, tibial tubercle-to-trochlear groove (TT-TG) distance, lateral patellar tilt (LPT), cartilaginous sulcus angle (CSA) and bisect offset ratio (BOR). CSA and BOR were included in the final predictive model, which correctly classified 89.4% of RPD cases.

CONCLUSION

Radiographical parameters that stratify risk of RPD in adults are also able to predict RPD in the pediatric population (TT-TG, LPT, CSA and BOR). Together, CSA and BOR accurately identified 89.4% of RPD. These measures should be included in the evaluation of pediatric patients who present with patellar dislocation.

LEVEL OF EVIDENCE

Level II.

Four-in-one Extensor Realignment for the Treatment of Obligatory or Fixed, Lateral Patellar Instability in Skeletally Immature Knee

BACKGROUND

Congenital (fixed) and obligatory (habitual) patellar dislocations in children are a complex clinical and surgical challenge. Numerous individual surgical techniques have been described. This study aims to assess results, patient satisfaction, and complications after a combined Roux-Goldthwait procedure, vastus medialis obliquus advancement, Galeazzi procedure, and extensive, lateral release (4-in-1 extensor realignment) in the skeletally immature knee with obligatory, or fixed lateral patellar instability.

METHODS

Records of children with congenital fixed or obligatory patellar instability, who underwent the 4-in-1 procedure at a single institution, were reviewed. Clinical results included ability and time for the return to activities of daily living (ADL) and sport, recurrent instability and/or dislocation, and necessity of long-term bracing. Continued pain was assessed by the Kujala Score. Complications including infection, recurrent instability, and the necessity for secondary procedures were recorded.

RESULTS

A total of 34 patients (46 knees) mean age 10.3±2.4 years, underwent the 4-in-1 procedure with a mean postoperative follow-up of 51.6±31.5 (range, 12 to 146) months. Sixteen patients (22 knees) responded to a phone interview and questionnaire. All 16 patients returned to ADL in a mean time of 10.3±2.4 weeks. Ninety-one percent returned to sport in a mean time of 23.1±15.5 weeks. Long-term bracing was required for 6 knees after the surgery. The mean Kujala Score was 93.0±5.2 (range, 83 to 100). Complications included 6 of 34 patients (18%) with recurrent instability at the latest follow-up and 2 with superficial wound infection.

CONCLUSIONS

Patients with obligatory or fixed lateral, patellar instability who undergo the 4-in-1 procedure have good short-term results with low complication rates. Return to ADL and sporting activity with minimal pain can be expected, usually without the need for long-term bracing. The 4-in-1 procedure is a viable option for skeletally immature patients with obligatory or fixed, lateral patellar instability.

LEVEL OF EVIDENCE

Level IV-Therapeutic study.

[Combined operation involving tibial tubercle distalization for recurrent patellar dislocation with patella alta]

Objective

To explore the clinical effects of combined operation involving tibial tubercle distalization for the recurrent patellar dislocation with patella alta.

Methods

Between April 2010 and May 2016, 14 cases of recurrent patellar dislocation with patella alta were treated with combined operation involving tibial tubercle distalization. There were 5 males and 9 females with an average age of 18.5 years (range, 13-26 years). The left knee was involved in 9 cases and the right knee in 5 cases. The patella had dislocated 3.3 times on average (range, 2-5 times). The interval between the first dislocation and admission was 19.7 months on average (range, 4-60 months), and the main symptoms were knee pain and limited knee movement. Preoperative X-ray films, CT, and MRI examinations of knee joint showed that the epiphyseal plate closed in all patients. Of all patients, 3 patients had avulsion fracture of the inner edge of patella, and 2 patients had free body in articular cavity. The tibial tuberosity-trochlear groove (TT-TG) distance, patellar-trochlear-groove distance, Caton-Deschamps index, knee range of motion (ROM), Lysholm score, International Knee Documentation Committee (IKDC) score, Kujala score, and Tegner score were compared pre- and post-operation.

Results

All patients had primary wound healing. All patients were followed up 24-72 months with an average of 34.6 months. X-ray film and CT examination showed that the patellar dislocation was corrected and the osteotomy of the tibial tubercle healed with an average healing time of 3.8 months (range, 3-5 month). At 1 day and 1 year after operation, the TT-TG distance, patellar-trochlear-groove distance, and Caton-Deschamps index showed significant differences when compared with preoperative values ( P<0.05), but there was no significant difference between 1 day and 1 year after operation ( P>0.05). At the 1 year and 2 years after operation, the knee ROM, Lysholm score, IKDC score, Kujala score, and Tegner score showed significant differences when compared with preoperative values ( P<0.05), and there was no significant difference between the 1 year and 2 years after operation ( P>0.05).

Conclusion

Combined operation involving tibial tubercle distalization is a safe and reliable method, which has satisfactory short-term effectiveness for the recurrent patellar dislocation with patella alta.