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

Open and arthroscopic deepening trochleoplasty improves post-operative outcomes: A systematic review of the literature reveals lack of comparability between techniques

PURPOSE

Deepening trochleoplasty improves outcomes in patients with trochlear dysplasia. The aim of this systematic review was to present the outcomes after open thin-flap, open thick-flap and arthroscopic deepening trochleoplasty.

METHODS

A systematic review was conducted using the PRISMA guidelines. Literature was searched in the PubMed, EMBASE and Cochrane databases on 16 December 2024. All studies from the inception of the databases to the date of the search were included in the search. Studies were included if they examined patients with patellar instability and trochlear dysplasia treated with either open or arthroscopic deepening trochleoplasty and reported pre- and post-operative outcomes. Two independent reviewers screened titles and abstracts, reviewed the full text and performed the quality assessment.

RESULTS

A total of 32 studies, consisting of 1435 trochleoplasty cases in 1310 patients, were included. Of the included studies, 21 concerned open thin-flap trochleoplasty, 8 concerned open thick-flap trochleoplasty and 3 concerned arthroscopic trochleoplasty. The most used patient-reported outcome measures were the Kujala score, International Knee Documentation Committee score, visual analogue scale pain score, Lysholm Knee Score and Tegner Activity Scale; and the most reported radiological outcome measures were trochlear sulcus angle, trochlear bump, trochlear depth, tibial tubercle-trochlear groove distance, Caton-Deschamps index and patellar tilt. All three trochleoplasty techniques lead to improvements in post-operative outcome measures.

CONCLUSION

Deepening trochleoplasty improves post-operative outcome using both open thin-flap, open thick-flap and arthroscopic deepening technique. Comparison between the techniques is challenging due to low methodological quality of studies. Further research is needed to document treatment effect and improve patient outcome.

LEVEL OF EVIDENCE

Level IV.

'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.

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.

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.

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.

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.

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.

Functional outcomes after Medial Patellofemoral Ligament Reconstruction show inverted J-shaped relation with Body Mass Index

PURPOSE

Medial patellofemoral ligament reconstruction (MPFL-R) is a recognised surgical procedure for the treatment of recurrent patellofemoral instability with excellent outcomes reported. The aim of this study is to determine if body mass index can influence these outcomes.

METHODS

This is a single-centre retrospective analysis of a longitudinal patellofemoral database. Patients with recurrent patellar instability, without patellar alta or severe trochlear dysplasia were treated using a MPFL-R between 2015 and 2019 at The Robert Jones & Agnes Hunt Orthopaedic Hospital. The clinical efficacy following surgery was assessed by Kujula, International Knee Documentation Committee Score (IKDC), and EuroQol-5 score (EQ-5D) at baseline and up to 26 months post-operatively; their safety assessed by complication rate and requirement for further surgery. The effect of Body Mass Index (BMI) on clinical outcome was analysed using linear, curvilinear, and segmented models following propensity score weighting.

RESULTS

A total of 97 patients (97 Knees, mean age 25y) were analysed. Of these, 61 patients had a BMI < 30 kg/m² (mean age 23y, mean BMI 24) of which 7 patients (12.3%) required additional surgery. A further 36 patients had a BMI > 30 kg/m² (mean age 27y, mean BMI 36) of which 2 patients (5.6%) required additional surgery. The re-dislocation rate was 0% in each BMI group. Both groups had a significantly improved mean outcome following surgery, with improvements in mean IKDC above the minimum clinical important differences (MCID) of 20.5. BMI had an inverted J-shaped association with functional outcome, showing peak outcomes at BMI of 20.5 (95% CI 18.5 to 22.4; IKDC and Kujala) or BMI of 28 (EQ-5D index). No evidence for an association between BMI and complication risk was found.

CONCLUSION

BMI influences the functional outcomes in MPFL-R with an inverted J-shaped relation, without evidence it affected the complication or re-dislocation rate. In the absence of patella alta and severe trochlear dysplasia, an isolated MPFL reconstruction is a safe and effective procedure to treat patellar instability, with the best functional outcome in patients with a BMI around 20 to 21.

LEVEL OF EVIDENCE

Level III.

Grooveplasty Compared With Trochleoplasty for the Treatment of Trochlear Dysplasia in the Setting of Patellar Instability

Purpose

To compare the clinical efficacy in the resolution of patellar instability, patient-reported outcomes (PROs), and complication and reoperation rates between patients who underwent grooveplasty (proximal trochleoplasty) and patients who underwent trochleoplasty as part of a combined patellofemoral stabilization procedure.

Methods

A retrospective chart review was performed to identify a cohort of patients who underwent grooveplasty and a cohort who underwent trochleoplasty at the time of patellar stabilization. Complications, reoperations, and PRO scores (Tegner, Kujala, and International Knee Documentation Committee scores) were collected at final follow-up. The Kruskal-Wallis test and Fisher exact test were performed when appropriate, and P < .05 was considered significant.

Results

Overall, 17 grooveplasty patients (18 knees) and 15 trochleoplasty patients (15 knees) were included. Seventy-nine percent of patients were female, and the average follow-up period was 3.9 years. The mean age at first dislocation was 11.8 years overall; most patients (65%) had more than 10 lifetime instability events and 76% of patients underwent prior knee-stabilizing procedures. Trochlear dysplasia (Dejour classification) was similar between cohorts. Patients who underwent grooveplasty had a higher activity level (P = .007) and a higher degree of patellar facet chondromalacia (P = .008) at baseline. At final follow-up, no patients had recurrent symptomatic instability after grooveplasty compared with 5 patients in the trochleoplasty cohort (P = .013). There were no differences in postoperative International Knee Documentation Committee scores (P = .870), Kujala scores (P = .059), or Tegner scores (P = .052). Additionally, there were no differences in complication rates (17% in grooveplasty cohort vs 13% in trochleoplasty cohort, P > .999) or reoperation rates (22% vs 13%, P = .665).

Conclusions

Proximal trochlear reshaping and removal of the supratrochlear spur (grooveplasty) in patients with severe trochlear dysplasia may offer an alternative strategy to complete trochleoplasty for the treatment of trochlear dysplasia in complex cases of patellofemoral instability. Grooveplasty patients showed less recurrent instability and similar PROs and reoperation rates compared with trochleoplasty patients.

Level of Evidence

Level III, retrospective comparative study.

Two-type classification system for femoral trochlear dysplasia in recurrent patellar instability based on three-dimensional morphology

PURPOSE

Radiographic and two-dimensional (2D) CT/MRI analysis of femoral trochlear dysplasia play a significant role in surgical decision-making for recurrent patellar instability. However, the three-dimensional morphology of dysplastic trochlea is rarely studied due to the limitations of conventional imaging modalities. This study aimed to (1) develop a 3D morphological classification for trochlear dysplasia based on the concavity of the trochlear groove and (2) analyze the interrater reliability of the classification system.

METHODS

The 3D trochleae of 132 knees with trochlear dysplasia and recurrent patellar instability were reconstructed using CT scan data and classified using the innovative classification criteria between January 2016 and June 2020. A concave trochlear sulcus with sloped medial and lateral trochlear facets was classified as Type I trochlea. The trochlear groove with no concavity is classified as Type II. Furthermore, in Type II, the trochlea with the elevated trochlear floor at the proximal part was identified as IIa and the trochlea with the hypoplastic trochlear facets as IIb. The intra- and inter-rater reliability was examined using kappa (κ) statistics.

RESULTS

The 3D classification system showed substantial intra-rater agreement and moderate interrater agreement (0.581 ~ 0.772). The intra- and interrater agreement of Dejour's four-grade classification was fair-to-moderate (0.332 ~ 0.633). Eighty-one trochleae with concave trochlear sulcus were classified as Type I, and fifty-one without concavity as Type II. Twenty-five non-concave trochleae were classified as type IIa due to the elevated trochlear floor and 26 trochleae into IIb with the hypoplasia of trochlear facets.

CONCLUSION

This study developed a 3D classification system to classify trochlear dysplasia according to trochlear concavity and morphology of the trochlear facets. On CT/MRI scans or 3D reconstructions, the interpretation of features of dysplastic trochleae may vary, especially for the flat and convex trochleae. The novel system provides morphological evidence for when to consider trochleoplasty according to the different types of trochlear sulcus.