Complications and outcomes of trochleoplasty for patellofemoral instability: A systematic review and meta-analysis of 1000 trochleoplasties

The Presence of a Trochlear Bump and Patella Alta May Predict the Risk of Recurrent Instability After Isolated Medial Patellofemoral Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

Medial patellofemoral ligament reconstruction (MPFLR) is an excellent surgical option for patients with recurrent patellar instability. This technique has demonstrated significant improvements in patient-reported outcomes, high rates of return to sport, and low rates of failure. However, there is debate regarding the use of isolated MPFLR in the setting of concomitant pathoanatomic features such as patella alta, trochlear dysplasia, or a lateralized tibial tubercle.

PURPOSE

To estimate the overall relative effect sizes as well as strength of evidence supporting described risk factors for recurrent instability after isolated MPFLR.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, Embase, Cochrane, and Ovid/MEDLINE databases were queried. Clinical studies for outcomes of isolated MPFLR reporting recurrent instability and associated risk factors were included. Data for each risk factor analyzed by at least 2 studies were extracted, and the heterogeneity of studies was determined by I2 value. For variables evaluated in studies determined to have fair homogeneity, defined as I2 <25%, DerSimonian-Laird random-effects models were generated and effect sizes were represented as mean differences or odds ratios.

RESULTS

Nine studies examining risk for recurrent instability after isolated MPFLR were identified, with 5 overlapping risk factors with low heterogeneity between studies: age, sex, tibial tubercle to trochlear groove (TT-TG) distance, Caton-Deschamps Index (CDI), and trochlear dysplasia. There was strong evidence to support the risk of recurrent instability associated with CDI >1.3 (OR, 2.72; P = .02) and dysplasia with a trochlear bump (DeJour type B or D; OR, 3.28; P <.001). Age, sex, and TT-TG distance did not cause an increased risk of recurrent instability with currently available aggregate data.

CONCLUSION

There are signs of increased risk of failure of isolated MPFLR in the setting of DeJour type B and D trochlear dysplasia and patella alta (CDI, >1.3). Currently available data suggest that age, sex, and TT-TG distance do not cause a higher risk of recurrence for patients undergoing isolated MPFLR.

Isolated Medial Patellofemoral Ligament Reconstruction Results in Lower Failure and Complication Rates Than Isolated Trochleoplasty and Tibial Tubercle Osteotomy: A Systematic Review

PURPOSE

To evaluate outcomes and complications of isolated medial patellofemoral ligament reconstruction (MPFLR), tibial tubercle osteotomy (TTO), and trochleoplasty for management of patellar instability.

METHODS

A query of Scopus, PubMed, Google Scholar, Cochrane CENTRAL Register of Controlled Trials, and the Cochrane Database of Systematic Reviews was performed in accordance with 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included studies reported clinical outcome data after isolated MPFLR, TTO, or trochleoplasty for patellar instability with a minimum 12-month follow-up. Meta-analysis and data aggregation was not performed.

RESULTS

Thirty-six studies (5 trochleoplasty, 14 TTO, and 18 MPFLR) consisting of 1,389 patients (114 trochleoplasty, 374 TTO, and 1,001 MPFLR) were included. Risk of bias was assessed with the Methodological Index for Non-Randomized Studies score, which ranged from 11 to 12 in trochleoplasty, 10 to 18 in TTO, and 8 to 18 in MPFLR studies. Patient-reported outcome measures, including Lysholm score (trochleoplasty: 51.1-71 to 71-95; TTO: 57-63.3 to 84-98; MPFLR: 37.4-59.1 to 74-92.5), Kujala score (trochleoplasty: 56-71 to 78-92; TTO: 48.6-68 to 78-92; MPFLR: 53.3-60 to 81.5-92), visual analog scale for pain (trochleoplasty: 52-25; TTO: 54-76 to 14-27; MPFLR: 29 to 17, out of 100), and Tegner score (TTO: 3-4 to 3-4; MPFLR: 2.5-6 to 4.9-5), improved after all surgeries. Failure rates ranged from 0% to 33.3% after MPFLR, 0% to 30.8% after TTO, and 5.3% to 40% after trochleoplasty. Complication rates ranged from 0% to 14.7% after MPFLR, 1.6% to 58.3% after TTO, and 8% to 26.3% after trochleoplasty.

CONCLUSIONS

Isolated MPFLR, TTO, or trochleoplasty may be effective treatment options for patellar stabilization. Although failure rates were highest after isolated trochleoplasty and complication rates were highest after TTO, these procedures are not interchangeable as each addresses a specific pathology.

LEVEL OF EVIDENCE

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

Saline Irrigation Mitigates Chondrocyte Viability Changes During Trochleoplasty

BACKGROUND

Trochleoplasty aims to correct trochlear dysplasia, an osseous cause of patellar instability. The procedure involves the use of a high-speed bur directly under femoral articular cartilage, which may place chondrocytes at risk of thermal necrosis.

PURPOSE/HYPOTHESIS

The purpose of this study was to investigate the effect of irrigation and offset used during a trochleoplasty procedure on trochlear chondrocyte viability. It was hypothesized that thermal necrosis would be induced by burring and would be mitigated with saline irrigation.

STUDY DESIGN

Controlled laboratory study.

METHODS

Cadaveric trochlea were obtained and sectioned into 4 quadrants. Trochleoplasty was performed in each quadrant under one of the following randomized conditions: 3-mm offset with saline irrigation (3Wet), 3-mm offset without irrigation (3Dry), 5-mm offset with irrigation (5Wet), or 5-mm offset without irrigation (5Dry). A 3 × 8-mm strip of cartilage was obtained from the center of each quadrant and from an 8-mm control area. Cartilage samples underwent chondrocyte viability staining with calcein-acetoxymethyl and ethidium homodimer-1. Confocal imaging was performed, and viability across treatment and control groups was compared.

RESULTS

Eight cadaveric trochlea were obtained from 5 male and 2 female donors (mean age, 26.4 ± 5.6 years). Trochleoplasty was performed at a mean of 25.3 ± 1.3 days from donor death on 5 right and 3 left trochlea. On analysis, control cartilage viability (75.3% ± 12.9%) was greater than those for 5Dry (60.4% ± 9.3%; P = .001) and 3Dry (63.2% ± 13.4%; P = .002). Cartilage viabilities for 5Wet (70.5% ± 11.0%; P = .15) and 3Wet (66.1% ± 10.9%; P = .09) were not significantly different from that of the control. No other intergroup differences were seen.

CONCLUSION

Saline irrigation mitigates chondrocyte-induced thermal necrosis when performing trochleoplasty in this cadaveric model.

CLINICAL RELEVANCE

Saline irrigation should be used when performing a trochleoplasty, while offset of the trochleoplasty bur does not have an effect on cartilage viability.

Varus Producing Distal Femur Osteotomy Alters Radiographic Measurements Related to Patellofemoral Instability: A Cadaver Study

Varus-producing distal femoral osteotomy (DFO) is an established procedure to correct genu valgum in patients with osteoarthritis and gait abnormalities. DFO has also been proposed for the treatment of patellar instability in patients with valgus alignment. However, it is not known how DFO affects parameters associated with patellar instability. This study evaluated radiographic changes after DFO with variable degrees of correction on six cadaveric knees, with the hypothesis that improving mechanical alignment would improve radiographic parameters related to patellar instability. Controlled laboratory is the study design. Six lower-limb cadaveric specimens were obtained after approval by the Institutional Review Board. A lateral opening wedge DFO was performed on each specimen with correction blocks of 6, 10, and 14 mm. The mechanical axis, tibiofemoral angle (mTFA), distal femoral angle (mDFA), Caton Deschamps index (CDI), insall salvati index (ISI), tibial tubercle to trochlear groove distance (TT-TG), and patellofemoral congruence angle (PFCA) were measured on computed tomography (CT) scans at baseline and after each correction block. At baseline, a mean varus alignment of the limbs was observed (mTFA: 2.7 ± 2.8 degrees, mDFA: 87.6 ± 1.0 degrees). The baseline patellar height was normal (CDI: 0.9 ± 0.2, ISI: 1.0 ± 0.1). Statistically significant decreases in mechanical axis and TT-TG distance and increases in mDFA and mFTA were found with increasing block size. The TT-TG distance was decreased by -1.6 mm (95% confidence interval [CI]: -2.27 to -0.86), -3.8 mm (95% CI: -4.8 to -2.8), and -4.0 mm (95% CI: -5.4 to -2.7) with a 6, 10, and 14 mm block, respectively. No differences were observed in patellar height when measured with CDI or ISI after any block size. In a cadaveric model, DFO significantly affects the mechanical axis and TT-TG distance. Specifically, this study found a mean decrease in TT-TG of -3.8 mm when performing a 10 mm opening wedge osteotomy. No changes in patellar height were observed.

Tibial tubercle torsion is associated with patellar height when measured by computed tomography

Purpose

To establish an average tibial tubercle (TT) torsion angle from computed tomography (CT) scans of patients without known patellofemoral instability and investigate whether TT torsion angles would differ based on demographics, tibial tubercle-trochlear groove (TT-TG) distance and patellar height.

Methods

The Stryker Orthopaedics Modeling and Analytics (SOMA) database was queried for patients with CT scans and available measures related to patella and TT position. The mean TT torsion angle was compared in patients with an increased and normal TT-TG distance (≥20 vs. <20 mm) and patellar height (Insall-Salvati [IS] index ≥1.3 vs. <1.3). Measurements of sulcus angle, patellar inclination angle, congruence angle, trochlear groove depth and long limb axis alignment were assessed.

Results

A total of 886 knees from 499 patients within the SOMA database were included, with a mean age of 59.4 ± 16.5 years and 238 (48%) females. The mean TT torsion angle for all patients was 24.7 ± 5.2°. Females had a significantly higher mean IS index (1.24 vs. 1.18), TT-TG distance (13.8 mm vs. 11.8 mm) and TT torsion angle (25.5° vs. 24.0°) compared to males. The mean TT torsion angle for patients with a TT-TG distance ≥20 mm and <20 mm was 24.7° in both groups (p = n.s.). There was a significantly greater TT torsion angle in patients with an IS index ≥1.3 (26.6°) compared to those with an IS index <1.3 (24.0°) (p < 0.001). A weak and positive correlation was found between TT torsion angle and IS index (r = 0.242, p < 0.001), but not with other measurements.

Conclusion

The mean TT torsion angle for patients without known patellofemoral instability was 24.7° and increased TT torsion angles were associated with increased patellar height. An association between TT torsion and TT-TG was not found. Findings of the current study describe the relationship between morphologic assessments of the patellofemoral joint using CT.

Level of Evidence

Level IV, cohort study.

Outcomes of Surgical Interventions for Patellofemoral Instability in the Presence of Trochlear Dysplasia: A Systematic Review and Meta-analysis

BACKGROUND

Patellar instability is frequently encountered by orthopaedic surgeons. One of the major risk factors of this condition is underlying trochlear dysplasia (TD). Recent trends have indicated the use of multiple procedures to correct patellar instability under these conditions. Medial patellofemoral ligament reconstruction (MPFLR) and trochleoplasty (TP) are surgical strategies that have demonstrated successful outcomes. However, it is unclear whether isolated MPFLR suffices for patellar instability in the presence of severe TD. Furthermore, the need for TP or a combined approach, considering its invasiveness and technical demands, to achieve better clinical outcomes and patellofemoral stability remains uncertain.

PURPOSE

To compare the outcomes of 3 surgical interventions for addressing patellar instability due to TD: MPFLR, TP, and combined MPFLR and TP.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

Studies reporting the clinical outcomes of MPFLR, TP, and both in combination, regardless of additional procedures, were identified using the MEDLINE, PubMed, Embase, Scopus, Cochrane Library, Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature databases. An important inclusion criterion was that studies should include the mean preoperative and postoperative Kujala scores and any complications. A random-effects model was used for the meta-analysis.

RESULTS

Overall, 30 studies were included: 10 describing the outcomes of TP, 13 describing the outcomes of MPFLR, and 7 describing the outcomes of combined TP and MPFLR. Furthermore, 1457 patients (1571 knees) were evaluated with a mean follow-up of 42.4 ± 32.8 months. No statistically significant differences were found between the 3 methods regarding the mean difference using the Kujala score. However, combined MPFLR and TP had the highest weighted mean difference compared with the other 2 procedures (28.5 points; P < .001). Evidential analysis revealed a robust log-likelihood ratio (S = 3.2) supporting the superiority of the combined procedure when comparing this mean and the weighted grand mean of 23.7. The redislocation rate after patellar stabilization remained minimal, irrespective of the surgical procedure (mean, 0.7%). However, the rate of residual patellar instability was the highest in the TP group (mean, 13.5%).

CONCLUSION

This study found no statistically significant difference between the outcomes of the 3 procedures. However, the combined approach of MPFLR and TP was associated with the most promising clinical outcomes and a low redislocation rate in patients with varying severities of TD.

Elevated Instability Resolution Angle Predicts Inferior Patient-Reported Outcomes in Isolated Medial Patellofemoral Ligament Reconstruction

Purpose

To investigate the prognostic utility of an examination under anesthesia (EUA) by evaluating the patient-reported outcome scores (PROs) and failure rates of patients undergoing primary, isolated medial patellofemoral ligament reconstruction (MPFLR) relative to their EUA findings.

Methods

A retrospective review was performed on patients who underwent primary, isolated MPFLR between August 2015 and August 2021. During the EUA the instability resolution angle (IRA) was identified by applying a lateral force on the patella through increasing knee flexion and defined by the degree of flexion the patella ceased lateral translation. PROs, including International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score Jr, and Kujala, were collected at 1-year and 2-year minimum after surgery. In addition, MPFLR failure was recorded and defined by patellar redislocation.

Results

In total, 94 patients met inclusion criteria, with 42 patients having an IRA <60° and 52 patients with an IRA ≥60° of knee flexion. At 2-year minimum follow-up, IKDC and Kujala PROs were significantly lower in patients with IRA ≥60° compared with patients with IRA <60° for both final and delta PROs. Mean tibial tubercle-trochlear groove distance examined on preoperative magnetic resonance imaging was 17.21 ± 5.00 mm for the IRA ≥60° cohort and 14.36 ± 4.89 mm for the IRA <60° cohort (P < .01). Four patients redislocated their patella, and all 4 had an IRA ≥60° (P = .07).

Conclusions

Patients who underwent isolated MPFLR with an IRA ≥60° had significantly lower IKDC and Kujala scores than similar patients with IRA <60° of knee flexion at 2-year minimum follow-up. Four (7.7%) patients with IRA ≥60° redislocated their patella, whereas zero patients with IRA <60° experienced redislocation.

Level of Evidence

Level III, retrospective cohort study.

Sulcus-deepening trochleoplasty and medial patellofemoral ligament reconstruction provide good clinical outcomes in addressing patellar instability at mid-term follow-up: A retrospective case series

PURPOSE

This study aimed to update previously published clinical and radiographic outcomes of Dejour sulcus-deepening trochleoplasty and medial patellofemoral ligament reconstruction (MPFL-R) at mid-term follow-up and monitor trends in patient-reported outcome scores and satisfaction.

METHODS

Using the same cohort of patients from our previously published short-term series of 2-year follow-up, an interval follow-up was performed on 67 patients (76 knees) with severe trochlear dysplasia and recurrent patellar instability who were prospectively enrolled and underwent Dejour sulcus-deepening trochleoplasty and MPFL-R combined with other patellar stabilization procedures. Patients with less than 2 years of follow-up were excluded. Evaluation involved radiographic analysis, physical examination, clinical follow-up, and patient-reported outcome scores.

RESULTS

A total of 37 patients (45 knees) were included in the current study, with a mean follow-up of 6.1 years postoperatively (standard deviation: 2.7 years). Two interval reoperations were performed (arthroscopic lysis of adhesions; hardware removal and arthroscopic shaving chondroplasty). There remained no occurrences of reoperation for recurrent patellar instability. Patient-reported outcomes were largely stable from early (mean: 3.6 years) to mid-term (mean: 6.1 years) follow-up, with no statistically significant difference between early and mid-term International Knee Documentation Committee (IKDC) (P ​= ​0.75), Kujala (P ​= ​0.47), or visual analog scale (VAS) pain (P ​= ​0.06) scores. Compared to preoperative knee scores, there was a significant difference in IKDC (49.3 vs 82.0, P ​< ​0.001, d ​= ​1.85), Kujala (56.5 vs 89.3, P ​< ​0.001, d ​= ​2.03), and VAS pain (3.8 vs 1.9, P ​= ​0.003, d ​= ​0.33) scores at mid-term follow-up (mean: 6.1 years). Mean Kellgren-Lawrence grading of patellofemoral arthritis showed no statistically significant change from 0.56 to 0.52 (P ​= ​0.511) on sunrise radiographs at the most recent follow-up.

CONCLUSIONS

At the mid-term follow-up, Dejour sulcus-deepening trochleoplasty and MPFL-R, combined with other patellar stabilization procedures, achieves durable resolution of patellar instability with maintained patient-reported outcome scores and satisfaction rates and is without interval evidence of clinical or radiographic progression of patellofemoral arthritis.

LEVEL OF EVIDENCE

IV, Case Series.

'À la carte' treatment algorithm for patellofemoral instability

Patellar instability is a complex and multifactorial problem that poses difficulties in treatment decision-making. The treatment algorithm proposed by the Lyon School of Knee Surgery aims to guide surgeons in identifying imaging risk factors for failure and proposing a therapeutic plan focused on correcting major risk factors present in specific case.

Patellofemoral Instability: Preoperative Considerations and Postoperative Imaging

Patellofemoral instability is common, often affecting young female patients. It contributes to significant morbidity, such as pain and premature osteoarthritis. Patient presentation varies, from acute instability events to chronic/recurrent instability. This article provides a detailed description of the anatomy and biomechanics of the patellofemoral joint and relates it to the pathology of patellofemoral instability. There are well-recognized predisposing anatomical factors, such as trochlear morphology, patella height, excessive lateralization of the tibial tubercle, excessive valgus alignment, and femoral or tibial torsion.Diagnosis of patellofemoral instability requires a thorough clinical history and physical examination, combined with a multimodality imaging approach. Imaging is useful in surgical planning to define the severity of predisposing anatomical factors and to detect postoperative complications. The operative management of patellofemoral instability targets predisposing anatomical factors, such as medial stabilizing ligament reconstruction or repair, tibial tubercle osteotomy, femoral trochleoplasty, coronal plane realignment osteotomy, and torsional osteotomy.

Good 5-year results and a low redislocation rate using an à la carte treatment algorithm for patellofemoral instability in patients with severe trochlea dysplasia

PURPOSE

Trochlear dysplasia is a major risk factor for recurrent patellar instability, reduced quality of life and osteoarthritis of the patellofemoral joint. Patellar instability in patients with trochlear dysplasia can be treated by trochleoplasty, usually in combination with medial patellofemoral ligament reconstruction (MPFL-R). An à la carte treatment algorithm, which also addresses patella alta, lateralisation of the tibial tuberosity and valgus or torsional malalignment when present has been standard in one clinic for treatment of patellar instability patients since 2009, based on the hypothesis that it results in optimal subjective and clinical outcome, normalisation of the lateral trochlea inclination (LTI) angle and a low rate of patellar redislocation.

METHODS

This prospective study reports the 5-year results for consecutive patients with high-grade trochlea dysplasia operated according to the algorithm 2010-2017, evaluated preoperatively and 1, 2 and 5 years postoperatively. Clinical information on previous surgery and postoperative patellar stability, range-of-motion (ROM) and subsequent surgery were registered. Subjective outcome was evaluated by four patient-reported outcome measures (PROMs): Kujala, Lysholm, International Knee Documentation Committee and Knee injury and Osteoarthritis Outcome Score. The LTI angle was measured pre- and postoperatively on magnetic resonance imaging scans.

RESULTS

There were 131 patients (87 females) with a median age of 22 years (range: 14-38). All had a trochleoplasty and an MPFL-R. Additional procedures (tibial tuberosity medialisation/distalisation and/or femoral/tibial osteotomy) were performed in 52%. All PROM scores improved from preoperatively to 1-year follow-up with further improvement at 2 and 5 years after surgery (p < 0.05). Three patients (2%) had a traumatic patellar dislocation 9, 12 and 24 months postoperatively and 38% underwent subsequent surgery (hardware removal, arthroscopically assisted brisement force, knee arthroscopy). A normalisation of the LTI angle (≥11°) was achieved in 76%.

CONCLUSIONS

Treatment according to the à la carte algorithm for patients with patellar instability and high-grade trochlear dysplasia resulted in significant clinical and subjective improvement in all PROM scores and a very low redislocation rate (2%) 5 years after surgery.

LEVEL OF EVIDENCE

Level II.

Anterior tibial tubercle internal torsion osteotomy (ATTITO) in patient with patellar instability

Anterior tibial tuberosity osteotomy is a well-described therapeutic option for the treatment of patellar instability. External torsion of the anterior tibial tuberosity can be one of several factors that adversely affect the patellofemoral joint and its stability. The Anterior Tibial Tubercle Internal Torsion Osteotomy (ATTITO) allows the correction of excessive external torsion of the tibial tuberosity in a safe and reproducible manner. LEVEL OF EVIDENCE: V.

Sulcus-deepening trochleoplasty grants satisfactory results with minimal patellofemoral arthritis at 23-30 years of follow-up

PURPOSE

The purpose of this study was to evaluate the radiographic and clinical outcomes of sulcus-deepening trochleoplasty at a minimum follow-up of 23 years.

METHODS

The authors evaluated a retrospective series of 10 patients (11 knees) who underwent trochleoplasty between 1993 and 2000. All patients were assessed at a minimum follow-up of 23 years by an independent clinician who noted any patellar redislocations and collected the International Knee Documentation Committee (IKDC), Kujala scores and range of motion. Radiographic examination was performed to assess patellofemoral arthritis using the Iwano classification.

RESULTS

A total of 11 knees, from five women and five men aged 25.6 ± 6.9 years (range, 15-47 years) underwent trochleoplasty during the inclusion period. All 11 knees underwent adjuvant procedures during trochleoplasty (100%): 10 had tibial tuberosity osteotomy (TTO) and vastus medialis plasty and 1 had only vastus medialis plasty (had prior TTO). At a follow-up of 24.4 ± 2.1 years (range, 23-30 years), two patients were lost to follow-up (18%). The Iwano classification was Grade 1 in three patients (33%), Grade 2 in four patients (44%) and Grade 4 in two patients (22%). The flexion range was 130 ± 8.7° and satisfaction was 9.2 ± 0.7, Kujala was 76.9 ± 8.5 and IKDC was 65.5 ± 13.8.

CONCLUSION

At 23-30 years following sulcus-deepening trochleoplasty in this small series of 10 patients (11 knees), patients had satisfactory clinical scores, only 1 patient reported an episode of traumatic patellar dislocation, and two knees had patellofemoral arthritis of Iwano Grade >2 (22%).

LEVEL OF EVIDENCE

Level IV.

Trochleoplasty Utilization in the Management of Patellofemoral Instability: Results From an International Survey of Surgeons

Background

Considerable variability exists in the described clinical and radiographic indications for use, surgical techniques, postoperative management, and risk profile after trochleoplasty for the management of patellofemoral instability (PFI). In areas of clinical uncertainty, a cohesive summary of expert opinion and identification of areas of variation in current practice can be useful in guiding current practice and future research efforts.

Purpose

To assess the current indications for use, surgical techniques, postoperative rehabilitation practices, and observed complication profile for trochleoplasty in the management of PFI among surgeons who perform this procedure.

Study Design

Cross-sectional study.

Methods

A 21-item cross-sectional survey was developed to evaluate trochleoplasty in its current practice among surgeons around the world. The survey was distributed between December 2021 and April 2022 to the orthopaedic surgeon membership of multiple national and international knee, arthroscopy, and sports medicine societies to identify any surgeon with experience performing the trochleoplasty procedure in practice for the management of PFI. Descriptive statistics of survey responses were performed to address study aims, and univariate analyses were performed to compare differences between high- and low-volume trochleoplasty surgeons.

Results

Survey distribution identified 32 orthopaedic surgeons with experience performing the trochleoplasty procedure. Procedural indications were most commonly felt to be met with Dejour classification of B or D on magnetic resonance imaging. Trochleoplasty was felt by most to be appropriate as a primary surgical intervention for PFI. A majority of surgeons utilized a Bereiter (thin-flap) trochleoplasty technique with suture-based fixation and performed concurrent medial patellofemoral ligament reconstruction, but other concomitant procedures varied. Range-of-motion precautions and bracing practices varied among respondents, and arthrofibrosis was the most frequently cited observed complication. High- and low-volume trochleoplasty surgeons differed in their radiographic and age-based indications for the procedure.

Conclusion

Study findings indicated that variation exists in the surgical indicators, technique, and postoperative rehabilitation practices of trochleoplasty surgeons, with specific differences noted between high- and low-volume trochleoplasty surgeons. The results of this survey identified areas of equipoise and treatment variation that should direct future research efforts in the study of the trochleoplasty procedure.

Thin flap sulcus-deepening trochleoplasty in patellar instability yields good functional outcomes without progressive cartilage deterioration in the short-term follow-up-A retrospective single-surgeon cohort study

PURPOSE

Sulcus-deepening trochleoplasty (TP) effectively treats patellofemoral (PF) instability (PFI) caused by high-grade trochlear dysplasia (TD), but current evidence is based on small case series. We hypothesised, that TP would result in significant functional improvements and a low re-dislocation rate but would not accelerate the progression of PF cartilage deterioration.

METHODS

We retrospectively reviewed all TP cases performed by a single surgeon between 2015 and 2021. Inclusion criteria were postoperative Magnetic resonance imaging (MRI) >6 and >12 months and a clinical follow-up >12 months. Patients with simultaneous cartilage repair, open physes or incomplete records were excluded. Clinical outcomes were assessed using pre- and postoperative scores, postoperative Banff Patellofemoral Instability Instrument (BPII) 2.0 and Knee Injury and Osteoarthritis Outcome Score (KOOS), re-dislocation rate and patient satisfaction. PF cartilage was evaluated via Area Measurement and Depth & Underlying Structures (AMADEUS) scores preoperatively, at 6 months and at the final follow-up.

RESULTS

We included 113 patients (25.8 ± 8.3 years) with high-grade TD (Dejour B-D; mean lateral inclination angle: -2.9 ± 9.1°), 85% of whom had advanced cartilage lesions. All underwent TP, lateral retinacular lengthening (LRL) and medial patellofemoral ligament reconstruction (MPFL-R). After 34.8 ± 20.9 months, function, pain levels and Tegner scores improved significantly (p < 0.001). KOOS dimensions were: symptoms 79.9 ± 13.5, pain 86.4 ± 12.1, activity 91.9 ± 8.3, sports 71.7 ± 22.2 and quality-of-life 58.1 ± 23.8. BPII 2.0 was 64.3 ± 31.4. Preoperative AMADEUS scores (55.2 ± 17.4) remained stable at 6 months (p = 0.343) but improved to 58.4 ± 16.0 at 28.6 (12-89) months (p = 0.004). Complication and re-dislocation rates were 5.3% and 1.8%, with 93% patient satisfaction.

CONCLUSION

Sulcus-deepening TP with MPFL-R and LRL yields good to excellent short-term results without progressive chondral deterioration, enabling patients to return to their prior or higher activity levels despite advanced preoperative chondral lesions. TP can be considered a safe, joint-preserving technique for PF stabilisation.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Association Between Articular Incongruence After Trochleoplasty and Long-term Patellofemoral Osteoarthritis

Background

Trochleoplasty has shown promising results in selected patients with patellar instability. However, concerns persist regarding its potential relationship with long-term osteoarthritis (OA) and the underlying causes.

Purpose

To evaluate the correlation between postoperative patellofemoral incongruence after trochleoplasty and long-term OA.

Study Design

Cohort study; Level of evidence, 3.

Methods

The authors conducted a retrospective review of patients who underwent sulcus-deepening trochleoplasty between 2003 and 2013 and identified 43 patients after their initial search. All patients were assessed at a minimum follow-up of 10 years. Preoperative, immediate postoperative, and end-of-follow-up lateral and axial view knee radiographs were used to evaluate patellofemoral OA using the Iwano classification, the patellar articular surface angle (PA), and the trochlear articular surface angle (TA). Data on patellar redislocation, reoperations, and International Knee Documentation Committee (IKDC), Kujala, and patient satisfaction scores were also collected. Pearson correlation analysis was used to evaluate the relationship between articular surface angles and OA, and Spearman rank correlation analysis was used to assess the association between categorical and ordinal variables. A 2-tailed Student t test was used to compare the mean values of the clinical scores between groups.

Results

Ten patients (10 knees) met the inclusion criteria, with a mean follow-up of 15.3 ± 3.93 years. The PA and TA were 148.5°± 24.75° and 148.5°± 17.85°, respectively, with a mean patellofemoral incongruence of 21.4°± 16.03°. None of the patients had preoperative OA, and 4 (40%) developed postoperative OA: 2 with Iwano grade 1 and 2 with Iwano grade 2. Higher patellofemoral incongruence was found to correlate with the development of patellofemoral OA (P = .017). No independent correlation was found between the TA and OA (P = .553) or the PA and OA (P = .884). The satisfaction, Kujala, and IKDC scores were 8.2 ± 1.75, 82.5 ± 10.09, and 84.4 ± 9.79, respectively. Only 1 patient (10%) reported a traumatic patellar dislocation, none required reoperations, and all (100%) indicated they would undergo surgery again.

Conclusion

This study demonstrated that patellofemoral incongruence after trochleoplasty was associated with the development of long-term OA without an independent correlation with a flat trochlea or a flat patella.

Original surgical technique for the treatment of patellofemoral instability after failure of conservative treatment

INTRODUCTION

Acute patellar dislocation is a common but serious injury that can significantly impact a patient's functional prognosis. The objective of this retrospective study is to evaluate the clinical outcomes of arthroscopic medial patellofemoral ligament (MPFL) reconstruction and plication of the medial patellar retinaculum using suture anchors in adolescent patients with first-time acute patellar dislocation (APD) and MPFL insertion injury.

HYPOTHESIS

Tightening repair of the medial retinaculum complex can result in favorable clinical and functional outcomes in this patient population.

MATERIALS AND METHODS

A total of 84 adolescent patients with first-time APD and with an average age of 15.5 years (10-22) were included in the study. Of these patients, 61 (7 male and 54 female) underwent arthroscopic suture anchor plication for medial patellar retinaculum, while the other 23 were successfully treated non-operatively. Radiographic outcomes, including the congruence angle (CA), lateral patellofemoral angle (LPA), and patellar tilt angle (PTA), were evaluated preoperatively and at the last follow-up visit in the surgical group. Functional outcomes were assessed using the Lille Patello-Femoral Score, Lysholm Score, and Kujala Score at the same time points. In addition, the surgical and non-operative treatment success groups were compared in terms of both radiographic and functional outcomes.

RESULTS

Mean follow-up was 40.9 months (24-60). Fifty-nine knees showed excellent or good results postoperatively, 2 patients had a recurrent patellar subluxation. The Lille Patello-Femoral Score was 96.9±4.7 at the last follow-up. The subjective Lysholm Score and Kujala Score improved significantly, from 58.6 to 91.9 and from 60.4 to 88.9, respectively. The radiographic CA, LPA and PTA improved significantly, from 19.8±2.1° to -6.7±1.7°, from -7.4±2.2° to 5.7±1.8° and from 23.8±2.9° to 12.3±2.3°, respectively. There was no statistically significant difference in functional and radiographic assessments between the success with non-operative treatment group and the surgery group.

CONCLUSION

The results of this study suggest that arthroscopic MPFL insertion reconstruction and plication using suture anchors, which is less invasive and improves patella stability, can lead to favorable clinical and functional outcomes in adolescent patients with first-time acute patellar dislocation and insertion injury. This treatment approach should be considered as a viable option for this patient population.

LEVEL OF EVIDENCE

IV; monocentric retrospective descriptive study.

Evaluation of Patellar Dysplasia and Postoperative Pain After Mini-Open, Thin-Flap Trochleoplasty: A Retrospective Analysis of 75 Consecutive Cases

Background

The association between inherent patellar anatomy and postoperative pain after trochleoplasty in patients with patellar instability is poorly understood.

Purpose/Hypothesis

The study purpose was to evaluate outcomes after mini-open, thin-flap trochleoplasty. The hypothesis was that more severe patellar dysplasia would be correlated with increased postoperative pain after trochleoplasty.

Study Design

Case series; Level of evidence 4.

Methods

Patients with patellar instability who underwent mini-open, thin-flap trochleoplasty in combination with other individualized procedures between 2013 and 2022 were included. Patellar dysplasia was evaluated by calculating the Wiberg index at the widest and most distal cartilaginous parts of the patella on preoperative magnetic resonance imaging. At the postoperative follow-up, participants completed the visual analog scale for usual pain (VAS-U), Banff Patellofemoral Instability Instrument 2.0 (BPII), global rating of change scale, and an evaluation of their current symptom state. Redislocations and complications were recorded. The correlation between the Wiberg index and the VAS-U was calculated with the Spearman rho. Between-group analyses based on demographic and pathoanatomic features were conducted using the Mann-Whitney U test, independent-samples t test, and chi-square test.

Results

Included were 75 knees in 63 patients (median age at surgery, 19.1 years; IQR, 16-22 years) with a median follow-up of 44 months (IQR, 23.8-83.2 months). The median BPII score was 78.2 (IQR, 54.8-92.5), with 88% reporting an improvement in knee function relative to before surgery, but 21.1% remained dissatisfied with their current knee symptom state. New episodes of patellar dislocation were seen in 3 knees (4%), and 14 knees (18.7%) underwent reoperation with either revision surgery (n = 7; 9.3%) or arthroscopic synovectomy (n = 7; 9.3%). A weak positive, nonsignificant correlation was found between increased postoperative pain and a higher Wiberg index, both at the widest (r S = 0.16; P = .23) and most distal (r S = 0.02; P = .89) parts of the patella. Significantly worse VAS-U scores were seen in female versus male patients (P = .013).

Conclusion

Good patient-reported results with a low risk of redislocation were seen in the study cohort, but reoperation rates were high, and 21% of the patients remained dissatisfied with their current symptom state. More pronounced patellar dysplasia (increased Wiberg index) had only a poor association with more severe postoperative pain in the current study.

Sulcus-Deepening Trochleoplasty With Medial Patellofemoral Ligament Reconstruction: Outcomes at 10 to 20 Years

BACKGROUND

Recent systematic reviews on the outcomes of sulcus-deepening trochleoplasty with adjuvant medial patellofemoral ligament (MPFL) reconstruction at a follow-up of 2 to 6 years have found that the procedure grants good clinical outcomes with low redislocation rates. However, there is a lack of evidence in the literature regarding mid- and long-term follow-ups.

PURPOSE

To evaluate the radiographic and clinical outcomes of thick-flap sulcus-deepening trochleoplasty with MPFL reconstruction at a minimum follow-up of 10 years to assess the signs of patellofemoral arthritis, incidence of recurrent dislocation, and grade of patient satisfaction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The authors evaluated a retrospective series of 43 patients (48 knees) who underwent sulcus-deepening trochleoplasty between 2003 and 2013. All patients underwent thick-flap sulcus-deepening trochleoplasty with additional MPFL reconstruction. All patients were assessed at a minimum follow-up of 10 years by an independent clinician who noted any patellar redislocation or reoperations in the operated knee and collected the International Knee Documentation Committee (IKDC), Kujala, and satisfaction scores. Furthermore, a radiographic examination was performed to assess patellar height using the Caton-Deschamps index and patellofemoral arthritis using the Iwano classification.

RESULTS

At a mean follow-up of 14.8 ± 2.1 years (range, 10-20 years), 4 patients (4 knees) were lost to follow-up (8.3%). The satisfaction, Kujala, and IKDC scores were 8.2 ± 1.6, 77.5 ± 14.4, and 65.7 ± 13.5, respectively. Only 1 patient reported a traumatic patellar dislocation (2%). Radiographs at the final follow-up were available for 34 knees, which revealed Iwano grade 1 in 14 knees (41%), Iwano grade 2 in 7 knees (21%), and no patellofemoral arthritis in 13 knees (38%).

CONCLUSION

Sulcus-deepening trochleoplasty with MPFL reconstruction provides satisfactory results and prevents patellar redislocations with no or minimal patellofemoral arthritis.

Patellar dislocation recurrence after pediatric MPFL reconstruction: Bone tunnels and soft tissues versus suture anchors and interference screw

BACKGROUND

Several Medial Patellofemoral Ligament (MPFL) reconstruction techniques have been developed, and those with soft tissue fixation are often preferred in children because they allow the growth cartilage to be preserved. Nevertheless, the recurrence rate of patellar dislocation varies widely from one series to another, with no clear superiority of one technique in the pediatric setting. The objectives of this study were to compare the results of two tendon graft fixation techniques (tendon-tendon fixation and anchor-screw fixation) by analyzing: 1) the rate of patellar dislocation recurrence, 2) clinical outcomes, 3) tourniquet time and 4) complication rate.

HYPOTHESIS

The two tendon graft fixation techniques used in MPFL reconstruction are equivalent in terms of the patellar dislocation recurrence rate.

PATIENTS AND METHODS

This is a retrospective comparative study including 57 patients with a median age of 14 years (12-15 years) who underwent MPFL reconstruction between 2016 and 2020. The tendon graft was fixed upon itself, after passing through a patellar tunnel (Group A: tendon-tendon fixation; n=29) or by two anchors and an interference screw (Group B: anchor-screw fixation; n=28). The preoperative radiographic data were comparable in the two groups: patellar height [A: 1.3 (interquartile range (IQR): 1.2-1.4) / B: 1.2 (IQR: 1-1.4) (p=0.21)], tibial tuberosity to trochlear groove (TTTG) distance [A: 16 (IQR: 13-19) / B: 13.5 (IQR: 11.5-18.8) (p=0.12)], patellar tilt [A: 25 (IQR: 20-35) / B: 24.5 (IQR: 21-32) (p=0.93)]. For each technique, the rate of patellar dislocation recurrence, clinical and functional results (Kujala score, Marx activity score, Lille patellofemoral score), complications (pain, stiffness, revision) were analyzed. In addition to MPFL repair, 13 patients (2 in Group A, 11 in Group B) underwent additional orthopedic procedures to enhance patellar stability.

RESULTS

no patients were lost to follow-up and the median follow-up was 30 months (IQR: 20-38). The dislocation recurrence rate was higher in Group A, 6.9% (2/29) compared to none in Group B. The clinical results were comparable for the two groups with a Kujala score [A: 94 (IQR: 89-100) / B: 92 (IQR: 87.5-94.5) (p=0.12)]; Marx score [A: 10 (IQR: 7-11) / B: 9.5 (IQR: 7.5-12) (p=0.89)] and Lille patellofemoral score [A: 97 (IQR: 91-100) / B: 94 (IQR: 90-98) (p=0.21)]. The tourniquet time was shorter in Group A than in Group B, 61minutes (IQR: 52-71) versus 85minutes (IQR: 55-115) (p=0.024) excluding additional orthopedic procedures. The complication rate was 17.2% (5/29) in Group A (dislocation n=2, stiffness n=2, ATT (anterior tibial tuberosity) revision with screw removal n=1) and 10.7% (3/28) in B (pain n=1, ATT revision with screw removal n=2) (p=0.35).

CONCLUSION

Clinically, anchor-screw fixation appears to reduce the risk of patellar dislocation recurrence but this could not be statistically tested. On the other hand, the two techniques are comparable in terms of the functional results.

LEVEL OF EVIDENCE

III; retrospective case-control study.

A modified Delphi consensus statement on patellar instability: part II

Aims

The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process.

Methods

This was the second part of a study dealing with these aspects of management in these patients. As in part I, a total of 60 surgeons from 11 countries contributed to the development of consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered unanimous.

Results

Of 41 questions and statements on patellar instability, none achieved unanimous consensus, 19 achieved strong consensus, 15 achieved consensus, and seven did not achieve consensus.

Conclusion

Most statements reached some degree of consensus, without any achieving unanimous consensus. There was no consensus on the use of anchors in MPFL reconstruction, and the order of fixation of the graft (patella first versus femur first). There was also no consensus on the indications for trochleoplasty or its effect on the viability of the cartilage after elevation of the osteochondral flap. There was also no consensus on postoperative immobilization or weightbearing, or whether paediatric patients should avoid an early return to sport.

Sulcus-Deepening Trochleoplasty for High-Grade Trochlear Dysplasia: Demystifying the Procedure-a Review of the Current Literature

PURPOSE OF REVIEW

The most common and biomechanically influential pathoanatomic risk factor for recurrent patellofemoral instability is trochlear dysplasia. Sulcus-deepening trochleoplasty is a procedure developed to address high-grade trochlear dysplasia in the setting of patellofemoral instability. The purpose of this paper is to outline the current classification and surgical management of trochlear dysplasia as well as to review the current literature on the clinical outcomes and complications of sulcus-deepening trochleoplasty.

RECENT FINDINGS

This review outlines the most recent literature reporting evidence behind the decision-making to perform a trochleoplasty in the setting of patellofemoral instability and high-grade trochlear dysplasia. Critical parameters include grade of trochlear dysplasia, severity of symptoms, pertinent physical examination findings, surgical techniques, modifications for skeletally immature patients, and considerations for the revision setting. Historic studies have elicited concerns regarding high reported complication rates for trochleoplasty; however, recent studies consistently report good clinical outcomes and acceptable complication rates, similar to those of other patellar stabilizing procedures. The addition of a trochleoplasty in patients with high-grade dysplasia results in a lower re-dislocation rate, significant improvements in patient-reported outcome measures (PROMs) as well as high levels of patient satisfaction and return to sport. The use of sulcus-deepening trochleoplasty for the treatment of high-grade dysplasia and recurrent patellofemoral instability is a well-established technique with good outcomes and an acceptable complication profile. In patients with high-grade dysplasia, trochleoplasty results in lower re-dislocation rates, high patient satisfaction scores, and good clinical and functional outcomes. An understanding of trochleoplasty and its indications should be in the armamentarium of surgeons treating patellofemoral instability.

Derotational distal femur osteotomy combined with medial patellofemoral ligament reconstruction yields satisfactory results in recurrent patellar dislocation with excessive femoral anteversion angle and trochlear dysplasia

PURPOSE

The purpose of this study was to evaluate the clinical outcomes of medial patellofemoral ligament (MPFL) reconstruction combined with derotational distal femur osteotomy in patients with recurrent patellar dislocation who had excessive femoral anteversion angle and trochlear dysplasia.

METHODS

Between 2015 and 2020, 64 patients (64 knees) with recurrent patellar dislocation, who had excessive femoral anteversion angle (≥ 25°) and trochlear dysplasia and were surgically treated using derotational distal femur osteotomy and MPFL reconstruction, were eligible for this retrospective study. These patients were assigned to two groups according to the grade of trochlear dysplasia. Group A (type A trochlear dysplasia, n = 33) and Group B (type B, C, D trochlear dysplasia, n = 31). Preoperative and postoperative patellar tilt angle (PTA), Caton-Deschamps index (CD-I), tibial tubercle-trochlear groove (TT-TG) distance and femoral anteversion angle were evaluated. Patient outcomes were assessed using the preoperative and postoperative International Knee Documentation Committee (IKDC) score, Kujala score, Lysholm score, Tegner score, and visual analog scale (VAS) score.

RESULTS

A total of 64 patients (64 knees) were evaluated in this study, with a mean follow-up period of 28.4 ± 3.6 months. There were no cases of wound infection, osteotomy site fractures, deep venous thrombosis of the lower extremities, or re-dislocation in the two groups during the postoperative follow-up period. All patients returned to full extension and flexion. The postoperative Tegner score, Lysholm score, Kujala score, IKDC score, VAS score, PTA, CD-I, TT-TG distance, and femoral anteversion angle were significantly improved compared with the preoperative status (P < 0.05). There was no significant difference between the two groups (n.s.).

CONCLUSION

MPFL reconstruction combined with derotational distal femur osteotomy showed satisfactory clinical outcomes during follow-up in patients with recurrent patellar dislocation who had excessive femoral anteversion angle and trochlear dysplasia. Even patients with high-grade trochlear dysplasia showed satisfactory results. For those patients, additional surgery is not necessary.

LEVEL OF EVIDENCE

Level III.

C-Arm Guidance During Thin Flap Arthroscopic Trochleoplasty for Chronic Patellar Instability

The purpose of this paper is to provide a complete Technical Note for our treatment of choice for recurrent patellar dislocation in cases of trochlear dysplasia, especially in patients with types B and D trochlear dysplasia according to the Dejour classification. Different surgical procedures have been reported for the treatment of recurrent patellar instability. One of the most important anatomic factors to address when treating a recurrent patella dislocation is trochlear dysplasia. Few types of open trochleoplasty have been classically described to treat a dysplastic trochlea. However, in recent years, arthroscopic techniques have been reported to reduce invasiveness and complications as well as to improve accuracy and clinical outcomes. In this technique is described an arthroscopic thin-flap tracheoplasty with the use of C-arm guidance in order to precisely control the bone resection and to verify intraoperatively the disappearance of the radiologic landmarks used for diagnosis and classification of the dysplasia. The advantage of this technique is the precision in removal of the supratrochlear spur and bump, the accurate and delicate reshaping of the sulcus with preservation of cartilage vitality, combined with increased reproducibility and safety.

Patellar Tracking: An Old Problem with New Insights

Patellofemoral pain and instability are common indications for imaging that are encountered in everyday practice. The authors comprehensively review key aspects of patellofemoral instability pertinent to radiologists that can be seen before the onset of osteoarthritis, highlighting the anatomy, clinical evaluation, diagnostic imaging, and treatment. Regarding the anatomy, the medial patellofemoral ligament (MPFL) is the primary static soft-tissue restraint to lateral patellar displacement and is commonly reconstructed surgically in patients with MPFL dysfunction and patellar instability. Osteoarticular abnormalities that predispose individuals to patellar instability include patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Clinically, patients with patellar instability may be divided into two broad groups with imaging findings that sometimes overlap: patients with a history of overt patellar instability after a traumatic event (eg, dislocation, subluxation) and patients without such a history. In terms of imaging, radiography is generally the initial examination of choice, and MRI is the most common cross-sectional examination performed preoperatively. For all imaging techniques, there has been a proliferation of published radiologic measurement methods. The authors summarize the most common validated measurements for patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Given that static imaging is inherently limited in the evaluation of patellar motion, dynamic imaging with US, CT, or MRI may be requested by some surgeons. The primary treatment strategy for patellofemoral pain is conservative. Surgical treatment options include MPFL reconstruction with or without osseous corrections such as trochleoplasty and tibial tubercle osteotomy. Postoperative complications evaluated at imaging include patellar fracture, graft failure, graft malposition, and medial patellar subluxation. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Trochlear Shape and Patient-Reported Outcomes After Arthroscopic Deepening Trochleoplasty and Medial Patellofemoral Ligament Reconstruction: A Retrospective Cohort Study Including MRI Assessments of the Trochlear Groove

Background

Sparse objective data are available documenting changes of trochlear shape after trochleoplasty.

Purpose/Hypothesis

The purpose was to investigate whether standardized magnetic resonance imaging (MRI) measurements that characterize trochlear dysplasia (TD) change significantly after arthroscopic deepening trochleoplasty (ADT) combined with medial patellofemoral ligament (MPFL) reconstruction. It was hypothesized that MRI measurements would approximate normal values.

Study Design

Case series; Level of evidence, 4.

Methods

Patients who underwent ADT between October 2014 and December 2017 were considered for this study. The preoperative inclusion criteria for ADT surgery were patellar instability, a dynamic patellar apprehension sign at 45° of flexion, a lateral trochlear inclination (LTI) angle of <11°, and failed physical therapy. MRI was performed pre- and postoperatively, and standardized MRI measurements were calculated: LTI angle, trochlear depth, trochlear facet asymmetry, cartilage thickness, and trochlear height. The Banff Patella Instability Instrument 2.0 (BPII) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Kujala score were obtained pre- and postoperatively.

Results

A total of 16 knees in 15 patients (12 female and 3 male; median age, 20.9 years; range, 14.1-51.3 years) were evaluated. The mean follow-up time was 63.6 months (range, 23-97 months). The median LTI angle improved from 1.25° (range, -25.1° to 10.6°) preoperatively to 10.7° (range, -17.7° to 25.8°) postoperatively (P < .001), trochlear depth increased from 0.0 mm (range, -4.2 to 1.8 mm) to 3.23 mm (range, 0.25-5.3 mm) (P < .001), and trochlear facet asymmetry improved from 4.55% (range, 0.0%-28.6%) to 17.8% (range, 0.0%-55.6%) (P < .003). Cartilage thickness was unchanged: 4.5 mm (range, 1.9-7.4 mm) preoperatively and 4.9 mm (range, 0.6-8.3 mm) postoperatively (P = .796). BPII, KOOS, and Kujala scores improved significantly (P < .0034 for all).

Conclusion

Combined ADT and MPFL reconstruction led to statistically significant and clinically relevant improvements in patient-reported outcomes and standardized MRI measurements that characterize TD. The improvements corresponded to those obtained by open trochleoplasty. No significant reduction in cartilage thickness was seen.

The Femoral Sulcus Deepening Trochleoplasty of Lyon

The sulcus deepening trochleoplasty procedure has been described for the management of patellofemoral instability in patients with severe trochlear dysplasia. Here, we describe the updated Lyon sulcus deepening trochleoplasty technique. This technique with a stepwise approach allows one to prepare the trochlea, remove the subchondral bone, osteotomize the articular surface, and fix the facets with 3 anchors while minimizing the risk of complications.

Good patient satisfaction with low complications rate after trochleoplasty in patellofemoral instability

PURPOSE

Trochlear dysplasia has been recognized as the most common factor in patients with patellofemoral dislocation. Trochleoplasty is a surgical procedure whose primary goal is to modify the femoral trochlea's abnormal shape in patients suffering from patellar instability, requiring good surgical skills, correct indication, and accurate patient information.

METHODS

The review aims to describe preoperative planning, patient selection, most common surgical techniques, and clinical results of trochleoplasty in patellar instability in a reproducible manner.

RESULTS

Trochleoplasty can be considered a general term to describe a group of different procedures that reduce trochlear dysplasia's impact on patellar instability, aiming to restore patella-trochlear congruency, remove the supratrochlear bump, allowed a new groove positioning and are generally associated with other procedures. Recent studies showed satisfactory long-term results with the restoration of patellar stability, improving radiological findings of patellofemoral instability.

CONCLUSION

Trochleoplasty is a technically demanding technique, requiring careful patient selection, detailed knowledge, and surgical skills to avoid severe complications. Good patient satisfaction with a low risk of significant complications such as patellofemoral arthritis has been revealed. In conclusion, trochleoplasty should be systematically included in the treatment of patellar dislocation, if indicated.

LEVEL OF EVIDENCE

V.

Radiographic Evaluation of Pediatric Patients with Patellofemoral Instability

PURPOSE OF REVIEW

The purpose of this review is to highlight the radiographic assessments of utility in the evaluation of a pediatric patient with patellofemoral instability to facilitate a thorough work-up. Understanding of these measures is useful in understanding evolving research in this field, providing accurate patient risk assessment, and appropriately directing surgical decision-making.

RECENT FINDINGS

Recent literature has broadened the radiographic characterization of the pediatric patellar instability and its anatomic risk factors. Knee MRI can inform the assessment of skeletal maturity and novel axial alignment measurements may enhance our identification of patients at increased risk of recurrent instability. Additional improvements have been made in the objective measurement and classification of trochlear dysplasia. Knee MRI-based skeletal age assessments may obviate the need for hand bone age assessments in growing children with patellofemoral instability. Novel objective measures exist in the evaluation of pediatric patellar instability both in the assessment of axial alignment and trochlear dysplasia. Future work should focus on how these measures can aid in guiding surgical decision-making.