Trochleoplasty with a flexible osteochondral flap: results from an 11-year series of 214 cases

Good 5-year results and a low redislocation rate using an á 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 á 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.

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.

Patho-morphology of patellar instability in children and adolescents: A systematic review and meta-analysis

BACKGROUND

Children and adolescents have the highest incidence of patellar instability among the population. We aimed to identify patho-morphological and epidemiological factors associated with patellar instability, and to identify factors predisposing to recurrence in children and adolescents.

METHODS

Published and unpublished literature databases, conference proceedings and the reference lists of included studies were searched to the 14th of March 2024. Studies were eligible if they compared history characteristics, examination features and radiological parameters between patients with and without instability, or evaluated risk factors for instability recurrence. A random-effects meta-analysis was performed. Included studies were appraised using tools respective of study design.

RESULTS

The evidence was moderate to low in quality. Forty-five studies (including 9000 patients) were eligible. Tibial tubercle - tibial groove (TT-TG) distance (weighted mean difference [WMD] 5.96 mm, 95% Confidence Interval [CI]: 4.94 to 6.99 mm), sulcus angle (WMD: 13.93˚, 95% CI: 9.1˚ to 18.8˚), and Insall-Salvati index (WMD: 0.2, 95% CI: 0.16 to 0.23) were greater in patients with patellar instability. Risk factors for recurrent dislocation included age less than 18 years (Odds ratio [OR]: 2.56, 95% CI: 1.63 to 4.0), skeletal immaturity (OR: 1.79, 95% CI: 1.21 to 2.64) and presence of trochlear dysplasia (OR: 3.37, 95% CI: 1.85 to 6.15).

CONCLUSION

Knowledge of patho-morphological factors associated with patellar instability could help explain its pathophysiological processes, allowing for the design of treatment approaches and the identification of patients at risk.

Trochleoplasty Provides Good Outcomes for Recurrent Patellofemoral Dislocations with No Clear Superiority across Different Techniques

Background: Literature is sparse on outcome comparisons between different trochleoplasty techniques in the treatment of patella instability. To date, it is unclear whether there is a technique that offers superior outcomes. This systematic review and meta-analysis aims to compare and evaluate the outcomes of trochleoplasty techniques in the treatment of patellofemoral instability in trochlea dysplasia to establish whether there is an ideal choice of trochleoplasty technique for superior outcomes. Methods: 21 studies involving 880 knees were included. The mean age of the patients was 21.7 years (range 8-49 years). Mean follow-up timeframe of 43.5 months (range 8.8-100 months). Clinical outcomes assessed included rates of recurrence of patellofemoral dislocation, patient satisfaction, Kujala score, International Knee Documentation Committee (IKDC) score, Tegner score, and Lysholm score. Egger's test showed no publication bias across all outcomes assessed. Results: Favourable results were seen across all outcomes assessed and patient satisfaction. Improvements were seen with Kujala, IKDC, and Lysholm scores. Tegner scores showed good return to function. Post-operative dislocation and complication rates were low across the different techniques. Meta-regression for Kujala and IKDC scores showed good outcomes regardless of trochleoplasty technique used (Kujala, p = 0.549, relative risk 492.06; IKDC, p = 0.193, RR 0.001). The exact risk that trochleoplasty poses to the cartilage remains uncertain, as no study had a conservatively managed arm for comparison. Conclusions: Trochleoplasty yielded good outcomes irrespective of technique used with no clear superiority demonstrated in any technique in terms of outcome scores, satisfaction, post-operative dislocation rates or complications.

No significant difference in thick versus thin osteochondral flap trochleoplasty in the treatment of trochlear dysplasia: A systematic review

PURPOSE

Trochleoplasty has become increasingly utilised to address patellar instability in the setting of severe trochlear dysplasia. There remains a paucity of literature on the outcomes of 'thick'- versus 'thin'-osteochondral flap trochleoplasty. The purpose of this study is to compare clinical and radiographic outcomes between patients with patellar instability with symptomatic trochlear dysplasia treated using a 'thick' versus 'thin' osteochondral flap trochleoplasty.

METHODS

A systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using a PRISMA checklist. Quality assessment of final articles was conducted by two blinded reviewers. Articles were separated based on the use of a 'thick' versus 'thin' flap trochleoplasty. Data collection consisted of recording the following variables: patient demographics, indications for trochleoplasty, mean follow-up time, additional procedures performed during trochleoplasty, patient-reported outcome measures (PROMs), radiographic outcomes (tibial tubercle-trochlear groove [TT-TG] distance, Caton-Deschamps Index [CDI] and sulcus angle [SA]) and the incidence of any postoperative complications and patellar redislocation rates.

RESULTS

A total of 24 studies, consisting of 927 patients, were identified as meeting inclusion criteria. A total of five papers described a 'thick' flap technique, while 19 papers described the use of a 'thin' flap technique. No significant difference in the mean improvement of Kujala scores was appreciated when comparing 'thick' versus 'thin' techniques (p > 0.05). Improvements in mean radiographic outcomes based on TT-TG, CDI and SA were observed in both 'thick' and 'thin' flap trochleoplasty groups. The overall redislocation rate was 0.35%.

CONCLUSION

No significant difference in Kujala scores was observed in patients undergoing trochleoplasty utilising 'thick' versus 'thin' technique, while improvements in mean TT-TG, CDI and SA were noted in both technique groups, with an overall redislocation rate of 0.35%.

LEVEL OF EVIDENCE

Level IV.

Sulcus deepening trochleoplasty versus bereiter trochleoplasty for high grade trochlear dysplasia: A systematic review and meta-analysis for clinical outcome and recurrent instability

BACKGROUND

Trochlear dysplasia is a condition in which the femoral trochlea has an abnormal shape and function. Trochleoplasty aims to change the shape of the trochlea in order to stabilize an unstable patella. This study compared clinical outcomes and recurrent instability after surgery between sulcus deepening trochleoplasty (Lyon) and Bereiter trochleoplasty in patients with high-grade trochlear dysplasia.

METHODS

We conducted a meta-analysis comparing Bereiter and Lyon trochleoplasty based on PRISMA guidelines regarding clinical outcome and recurrent instability for high-grade trochlear dysplasia. Searching on five databases, we found 11 eligible studies with a total of 520 subjects to be analysed. Studies were qualitatively and quantitatively evaluated using Review Manager 5.4 or equivalent.

RESULTS

Both techniques showed no differences in sulcus angle, return-to-sport rate, and satisfactory rate. The IKDC and Kujala scores showed good outcomes but were not significantly different. IKDC score was not different after analysis between Bereiter and Lyon techniques. The pooled improvement of IKDC score on both subgroups was 24.39 (95% CI 21.14-27.65). A pooled analysis of 10 studies found that the Kujala score did not differ between groups with Bereiter and Lyon techniques. The total pooled mean difference of both groups was 25.87 (95% CI 21.70-30.05).

CONCLUSION

None of the techniques analysed highlighted an absolute superiority. Clinical relevance showed both techniques have good clinical outcomes, fewer complications, and recurrent instability for high-grade trochlear dysplasia.

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.

Intraoperative control by Schanz-screws is inaccurate to achieve the exact amount of correction in de-rotational osteotomies

PURPOSE

The accuracy of intraoperative control of correction commonly is achieved by K-wires or Schanz-screws in combination with goniometer in de-rotational osteotomies. The purpose of this study is to investigate the accuracy of intraoperative torsional control in de-rotational femoral and tibial osteotomies. It is hypothesized, that intraoperative control by Schanz-screws and goniometer in de-rotational osteotomies around the knee is a safe and well predictable method to control the surgical torsional correction intraoperatively.

METHODS

55 consecutive osteotomies around the knee joint were registered, 28 femoral and 27 tibial. The indication for osteotomy was femoral or tibial torsional deformity with the clinical occurrence of patellofemoral maltracking or PFI. Pre- and postoperative torsions were measured according to the method of Waidelich on computed tomography (CT) scan. The scheduled value of torsional correction was defined by the surgeon preoperatively. Intraoperative control of torsional correction was achieved by 5 mm-Schanz-screws and goniometer. The measured values of torsional CT scan were compared to the preoperative defined and intended values and deviation was calculated separately for femoral and tibial osteotomies.

RESULTS

The surgeon's intraoperative measured mean value of correction in all osteotomies was 15.2° (SD 4.6; range 10-27), whereas the postoperatively measured mean value on CT scan was 15.6 (6.8; 5.0-28.5). Intraoperatively the femoral mean value measured 17.9° (4.9; 10-27) and 12.4° (1.9; 10-15) for the tibia. Postoperatively the mean value for femoral correction was 19.8 (5.5; 9.0-28.5) and 11.3 (5.0; 5.0-26.0) for tibial correction. When considering a deviation of plus or minus 3° to be acceptable femorally 15 osteotomies (53.6%) and tibially 14 osteotomies (51.9%) fell within these limits. Nine femoral cases (32.1.%) were overcorrected, four cases undercorrected (14.3%). Four tibial cases of overcorrection (14.8%) and 9 tibial cases of undercorrection (33.3%) were observed. However, the observed difference between femur and tibia regarding the distribution of cases between the three groups did not reach significance. Moreover, there was no correlation between the extent of correction and the deviation from the intended result.

CONCLUSION

The use of Schanz-screws and goniometer in de-rotational osteotomies as an intraoperative control of correction is an inaccurate method. Every surgeon performing derotational osteotomies must consider this and include postoperative torsional measurement in his postoperative algorithm until new tools or devices are available to guarantee a better intraoperative accuracy of torsional correction.

STUDY DESIGN

Observational study.

LEVEL OF EVIDENCE

III.

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.

Correction of tibial tubercle trochlea groove distance is related to torsional correction in high tibial derotational osteotomy

PURPOSE

High tibial osteotomy with internal tibial derotation (high tibial derotation osteotomy = HTDRO) is a common surgical treatment in patients with patellofemoral malalignment alone or in combination with patellofemoral instability. Operative techniques and theoretical calculations may assume that correction of the tibial tubercle-trochlear groove (TTTG) distance is related to the amount of torsional correction. The purpose of this investigation was to predict the change in TTTG distance in HTDRO through a clinical study.

METHODS

Twenty-one consecutive cases of derotational HTO were evaluated by torsional CT scanning in terms of the pre- and postoperative tibial torsion and TTTG distance. Changes in the TTTG distance were related to the changes in the amount of torsional correction. The change in patellar height was measured pre- and postoperatively, and the Caton-Deschamps Index (CDI) was calculated.

RESULTS

The mean change in tibial torsion was 13.9°, and the mean change in the TTTG distance was 6.3 mm. A strong relationship (0.90) between the change in torsion and the change in TTTG distance from pre- to postoperative status was found (p < 0.001). No statistically significant change in CDI could be seen between the preoperative [mean value (MV) 1.0] and postoperative (MV 1.1) periods.

CONCLUSIONS

In patients with patellofemoral instability or patellofemoral maltracking with both a high tibial external torsion and a high TTTG distance, a derotational HTO can correct both bony deformities. Patella height does not change significantly with this surgical technique. With 1° of torsional correction, the TTTG distance decreases 0.45 mm with our surgical technique of derotational HTO.

The pathologic double contour sign and the trochlea shape patterns can diagnose trochlea dysplasia

OBJECTIVES

The goal of this study is to describe the distinct morphologic patterns of the normal and dysplastic trochleae, the trochlear shape patterns (TSP) seen on the axial views of MRI scans.

METHOD

Two cohorts of patients were used for comparison. Cohort 1: MRI scans of 100 patients with no history of patella instability. Cohort 2: MRI scans of 66 patients diagnosed with severe trochlea dysplasia and patella instability. The presence of the pathologic double contour (PDC) sign and the type of TSP were identified in the axial views at the level of three specific anatomical references: Trochlear Specific Zone 0 (TSZ 0), posterior femoral condyle line (PFCL) and transverse distal femoral physis line (tv-DFPL). The pathologic double contour sign is an area of flat or convex lateral trochlea which is elevated over the contour of the medial femoral condyle. Three basic morphologic patterns of trochlear shape were identified. TSP type 1 (normal trochlea): There is no PDC. There is a clearly defined sulcus delineating the lateral and medial trochlear facets (sulcus angle <165°). TSP type 2 (normal but shallow trochlea): There is no PDC. The trochlear groove is shallow (sulcus angle >165°), but the lateral and medial facets are present. TSP type 3: This pattern is characterised by the presence of a PDC. The chi-square test was used to determine whether the distribution of the TSP was the same between the two cohorts at the anatomical reference lines.

RESULTS

The differences observed in distribution of the TSP between the two cohorts were statistically significant. There was a strong positive correlation between the morphology of the trochlea (TSP) and patella instability. All patients in the patella instability cohort showed a PDC.

CONCLUSION

Normal trochleae show TSP type 1 and 2 proximal to the tv-DFPL. The presence of the pathologic double contour sign and trochlea shape pattern type 3 (TSP 3) proximal to the tv-DFPL (PFCL or TSZ 0) are diagnostic of trochlea dysplasia.

Low re-dislocation rate following Bereiter trochleoplasty for recurrent patellar instability with severe trochlear dysplasia

PURPOSE

Trochlear dysplasia is an independent risk factor for recurrent patellar instability with evidence demonstrating its presence in up to 85% of patients with patellar instability. Severe trochlear dysplasia can be treated with trochleoplasty to improve engagement of the patella in the trochlear groove and prevent future dislocations. The aim of this study was to determine the clinical outcome of Bereiter trochleoplasty in patients with recurrent patellar instability and severe trochlear dysplasia.

METHODS

This was a retrospective case series of all trochleoplasties performed in our institution from 2008-2019. All clinical records and pre-operative MRI scans were reviewed to assess for trochlear dysplasia, tibial tuberosity to trochlear groove distance (TTTG) and patella height using patella trochlear index (PTI). Trochlear dysplasia was classified using Dejour classification. Incidence of re-dislocation, infection, arthrofibrosis, chondral necrosis and re-operation were recorded. All patients were invited to complete a post-operative visual analog score for pain (VAS-P) and Banff Patella Instability Instrument (BPII).

RESULTS

Fifty-eight trochleoplasties were performed in fifty patients during this period. All trochleoplasties were combined with additional procedures. 93% had concomitant medial patellofemoral ligament (MPFL) reconstructions and 47% had tibial tuberosity transfer. The mean follow-up period was 36.8 months. The rate of dislocation and arthrofibrosis were 5% each. There were no chondral necrosis or nonunion. The mean post-operative BPII was 58.4 and VAS-P was 30.4.

CONCLUSIONS

Bereiter trochleoplasty, often combined with MPFL reconstruction and/or tibial tuberosity transfer results in low re-dislocation and complication rate.

LEVEL OF EVIDENCE

IV.

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.

Trochleoplasty for severe trochlear dysplasia significantly improves the quality of life of patients with symptomatic patellar instability

BACKGROUND

Trochleoplasty is a recognized surgical technique to address severe trochlear dysplasia. The clinical and radiological outcomes of trochleoplasty surgery in trochlear dysplasia have been well reported. There is a paucity in literature regarding the correlation between trochleoplasty and quality of life (QoL). The aim of this study is to measure the improvement in QoL, in patients with severe trochlear dysplasia and recurrent patellar instability following trochleoplasty.

METHODS

Between 2013 and 2019, 51 trochleoplasty cases were performed in 48 patients. They were identified from our prospectively kept database. All operations were performed by a fellowship trained consultant sports knee surgeon. Functional outcomes and QoL scores were assessed using Kujala, IKDC and EQ-5D index. Objective outcomes were obtained following each patient's latest follow-up assessment.

RESULTS

The mean age at operation was 22y (SD ± 4.7, range 14-37y) and the mean follow-up period was 21.6 months (SD ± 15.2, range 12-60 months). The mean Kujala score improved from 58.1 (SD 14.9) to 77.9 (SD 17.3) at latest follow-up (p < 0.001). The mean IKDC score improved from 40.5 (SD 14.2) to 69.5 (SD 22.8) at latest follow up (p < 0.001). The mean EQ-5D index also improved from 0.593 (SD 0.257) to 0.824 (SD 0.189) at latest follow-up (p = 0.003). A higher Body Mass Index (BMI; >30 kg/m²) was associated with inferior outcomes.

CONCLUSION

Trochleoplasty is an effective surgical technique which improves the QoL in patients suffering from patellar instability secondary to severe trochlear dysplasia. BMI can be used to predict post-operative outcomes.

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.

Return to Sports and Patients' Rehabilitation Continuum After Deepening Trochleoplasty and Concomitant Patellar-Stabilizing Procedures: A Case Series of 111 Patients at 2 to 4 Years of Follow-up

BACKGROUND

There are few reports on the return to sports after complex patellar-stabilizing surgery.

PURPOSES

To evaluate patients' ability to return to sports and to investigate the extent to which the preoperative level of sports participation influences sports activity after deepening trochleoplasty (TP) and concomitant patellar-stabilizing procedures.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between April 2015 and April 2019, 144 patellar-stabilizing procedures, including deepening TP and medial patellofemoral ligament reconstruction or medial reefing with and without concomitant realignment procedures, were carried out in 142 patients. The Banff Patellofemoral Instability Instrument 2.0 (BPII 2.0) and the Tegner activity score were used to assess patients' quality of life and sports activity level. In addition, a numerical analog scale was used to evaluate patellofemoral pain intensity during rest and activity and subjective knee joint function.

RESULTS

Outcomes were available for 111 patients (112 knees) (male/female, 77/34; mean age, 23.4 ± 7.8 years), yielding a 77.7% follow-up rate at a mean of 39.2 ± 9.9 months (range, 24-48 months). Two-thirds of the patients returned to their preoperative level of activity or higher, but their Tegner scores did not change significantly (4.5 ± 2.4 vs 4.7 ± 1.6; P = .365). Low-level athletes (preoperative Tegner score 0-4) participated at a higher level of sports activity (2.7 ± 1.4 to 4.1 ± 1.2; P < .0001), whereas higher-level athletes (preoperative Tegner score 5-10) participated at a lower level (6.8 ± 1.3 to 5.5 ± 1.7; P < .0001). The likelihood of returning to the preoperative activity level (Tegner score) was significantly higher in the low-level activity group than in the high-level activity group (P = .0001; 95% CI, 4.055-27.05; odds ratio, 10.47). All of the patient-reported outcome measures improved postoperatively, independent of the patients' age, sex, and body mass index.

CONCLUSION

Patients undergoing deepening TP and medial soft tissue stabilization with or without concomitant realignment surgery for complex patellar instability can expect good clinical results and a high rate of return to sports participation, with two-thirds of patients returning to their preoperative Tegner-level of activity or higher. However, higher-level athletes should be informed that their likelihood of returning to sports at the preoperative level or full participation at a competitive level is reduced.

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

BACKGROUND

Trochleoplasty is an effective patellar stabilization procedure; however, it is associated with a risk of complications that cannot be ignored. Prior systematic reviews on this topic did not include more recent studies reporting important outcomes, particularly the long-term results of lateral elevation trochleoplasty. This led us to carry out a new meta-analysis of the various trochleoplasty procedures to specify: (1) the recurrence rate of patellofemoral dislocation; (2) the complication rates and; (3) the clinical outcomes.

PATIENTS AND METHODS

Studies reporting complications and clinical outcomes of trochleoplasty, whether or not it was combined with other procedures for patellofemoral instability, were identified in the MEDLINE, Embase, Scopus, Cochrane Library, Web of Science databases and by searching the grey literature. The primary endpoint was the recurrence of patellofemoral dislocation while the secondary endpoints were objective patellofemoral instability without dislocation, stiffness, patellofemoral osteoarthritis, subsequent surgeries and various clinical outcome scores. The results were combined in a random-effects model (weighing factor: inverse variance) when the heterogeneity was less than 80%.

RESULTS

Twenty-eight studies were included: 5 featured lateral elevation trochleoplasty, 10 about the Dejour deepening trochleoplasty, 12 about the Bereiter deepening trochleoplasty and 1 about the recession wedge trochleoplasty. A total of 1000 trochleoplasty procedures were done in 890 patients who had a follow-up of 1 to 25 years. There were 24 cases of recurrent dislocation (24/994 [2.4%]; this outcome was not reported for 6 trochleoplasties). The Dejour deepening trochleoplasty was the most effective with only 1 recurrence in 349 knees (0.28%). For the other complications, residual patellar instability without dislocation occurred in 82 of 754 knees (8% [95% CI: 3-14%]), patellofemoral osteoarthritis in 117 of 431 knees (27%), stiffness in 59 of 642 knees (7% [95% CI: 3-12%]) and the need for subsequent surgery in 151 of 904 knees (17%).

DISCUSSION

This study found a low recurrence rate for patellofemoral dislocation and residual instability. The incidence of stiffness, patellofemoral osteoarthritis and subsequent surgery remains high but differs greatly between studies. This meta-analysis showed a very large disparity between studies for most complications, which justifies the need for randomized and comparative studies to establish the role of trochleoplasty procedures in the treatment algorithm for patellar instability.

LEVEL OF EVIDENCE

IV; systematic review and meta-analysis.

Dysplastic Patellofemoral Joints Lead to a Shift in Contact Forces: A 3D-Printed Cadaveric Model

BACKGROUND

The distribution of contact forces across the dysplastic patellofemoral joint has not been adequately quantified because models cannot easily mimic the dysplasia of both the trochlea and the patella. Thus, the mechanical consequences of surgical treatments to correct dysplasia cannot be established.

PURPOSE/HYPOTHESIS

The objective of this study was to quantify the contact mechanics and kinematics of normal, mild, and severely dysplastic patellofemoral joints using synthetic mimics of the articulating surfaces on cadavers. We tested the hypothesis that severely dysplastic joints would result in significantly increased patellofemoral contact forces and abnormal kinematics.

STUDY DESIGN

Controlled laboratory study.

METHOD

Patellofemoral dysplasia was simulated in 9 cadaveric knees by replacing the native patellar and trochlear surfaces with synthetic patellar and trochlear implants. For each knee, 3 synthetic surface geometries (normal, showing no signs of dysplasia; mild, exemplifying Dejour type A; and severe, exemplifying Dejour type B) were randomized for implantation and testing. Patellar kinematics and the sum of forces acting on the medial and lateral patellar facets were computed for each knee and for each condition at 10° increments from 0° to 70° of flexion.

RESULTS

A pronounced lateral shift in the weighted center of contact of the lateral facet occurred for severely dysplastic knees from 20° to 70° of flexion. Compared with normal geometries, lateral patellar facet forces exhibited a significant increase only with mild dysplasia from 50° to 70° of flexion and with severe dysplasia at 70° of flexion. No measurable differences in medial patellar facet mechanics or joint kinematics occurred.

CONCLUSION

Our hypothesis was rejected: Severely dysplastic joints did not result in significantly increased patellofemoral contact forces and abnormal kinematics in our cadaveric simulation. Rather, severe dysplasia resulted in a pronounced lateral shift in contact forces across the lateral patellar facet, while changes in kinematics and the magnitude of contact forces were not significant.

CLINICAL RELEVANCE

Including dysplasia of both the patella and trochlea is required to fully capture the mechanics of this complex joint. The pronounced lateralization of contact force in severely dysplastic patellofemoral joints should be considered to avoid cartilage overload with surgical manipulation.

Clinical validation of the Oswestry-Bristol Classification as part of a decision algorithm for trochlear dysplasia surgery

AIMS

The Oswestry-Bristol Classification (OBC) is an MRI-specific assessment tool to grade trochlear dysplasia. The aim of this study is to validate clinically the OBC by demonstrating its use in selecting treatments that are safe and effective.

METHODS

The OBC and the patellotrochlear index were used as part of the Oswestry Patellotrochlear Algorithm (OPTA) to guide the surgical treatment of patients with patellar instability. Patients were assigned to one of four treatment groups: medial patellofemoral ligament reconstruction (MPFLr); MPFLr + tibial tubercle distalization (TTD); trochleoplasty; or trochleoplasty + TTD. A prospective analysis of a longitudinal patellofemoral database was performed. Between 2012 and 2018, 202 patients (233 knees) with a mean age of 24.2 years (SD 8.1), with recurrent patellar instability were treated by two fellowship-trained consultant sports/knee surgeons at The Robert Jones and Agnes Hunt Orthopaedic Hospital. Clinical efficacy of each treatment group was assessed by Kujala, International Knee Documentation Committee (IKDC), and EuroQol five-dimension questionnaire (EQ-5D) scores at baseline, and up to 60 months postoperatively. Their safety was assessed by complication rate and requirement for further surgery. The pattern of clinical outcome over time was analyzed using mixed regression modelling.

RESULTS

In all, 135 knees (mean age 24.9 years (SD 9.4)) were treated using a MPFLr. Ten knees (7.4%) required additional surgery. A total of 50 knees (mean age 24.4 years (SD 6.3)) were treated using MPFLr + TTD. Ten (20%) required additional surgery. A total of 20 knees (mean age 19.5 years (SD 3.0)) were treated using trochleoplasty + TTD. Three patients (15%) required additional surgery. In each treatment group, there was a significant improvement in Kujala, IKDC, and EQ-5D at one year postoperatively (p < 0.001) with a recognized level of overall complication rate.

CONCLUSION

The OBC is a valid assessment tool to grade patients with trochlear dysplasia and, when used as part of the OPTA, helps to determine treatments that are safe and effective. This fulfils the requirements for its application in mainstream clinical practice. Cite this article: Bone Joint J 2021;103-B(10):1586-1594.

Current Concepts Regarding Patellofemoral Trochlear Dysplasia

Optimal treatment of patients with patellofemoral trochlear dysplasia and recurrent patellar instability requires in-depth understanding of this complex structural anomaly. An extensive review of the literature suggests that dysplasia occurs as a result of aberrant forces applied to the patellofemoral joint in the majority of cases. Evidence supports surgical stabilization that reconstructs the medial patellofemoral and/or medial quadriceps tendon-femoral ligament without added trochleoplasty in the majority of patients with trochlear dysplasia and recurrent patellar instability. Adding tibial tubercle transfer distally, medially, or anteromedially in those who need it to treat specific deficits in alignment or articular cartilage can be beneficial in selected patients with trochlear dysplasia and recurrent patellar instability. Trochleoplasty may be appropriate in those few cases in which permanent stable patellofemoral tracking cannot be restored otherwise, but the indications are not yet clear, particularly as trochleoplasty adds risk to the articular cartilage. Improved understanding of imaging techniques and 3-dimensional reproductions of dysplastic patellofemoral joints are useful in surgical planning for patients with recurrent patellar instability and trochlear dysplasia.

Sulcus-Deepening Trochleoplasty as an Isolated or Combined Treatment Strategy for Patellar Instability and Trochlear Dysplasia: A Systematic Review

Purpose

To highlight the indications and outcomes for sulcus-deepening trochleoplasty, when used as an isolated procedure as well as in combination with other stabilization techniques for patellar instability.

Methods

We performed a systematic review focused on outcomes and complications following trochleoplasty performed either as an isolated procedure or in combination with other procedures to address patellar instability. Inclusion criteria included studies in English that reported on outcomes following primary open trochleoplasty, including Kujala scores and recurrent instability or dislocation events.

Results

Twelve papers including 702 patients who underwent sulcus-deepening trochleoplasty were included. A total of 504 patients underwent isolated sulcus-deepening trochleoplasty, whereas 198 patients underwent trochleoplasty in combination with 1 or more additional stabilization procedures. In total, 67% of patients were female compared with 33% male. The procedure was done was a primary surgical intervention 74% of the time. Postoperative Kujala scores for isolated trochleoplasty ranged from 80 to 92, whereas those for combined stabilization procedures ranged from 76 to 95. The dislocation rate among the studies ranged from 0 to 8%. There was a persistent J-sign in 0 to 12% of treated knees among all studies, and a persistent apprehension test in 0 to 29% of treated knees. Return to play ranged from 65% to 83% in studies in which this was reported as an outcome.

Conclusions

Sulcus-deepening trochleoplasty performed for recurrent patellar instability in the setting of trochlear dysplasia results in improved Kujala scores and a low redislocation rate, when performed as an isolated procedure or in combination with other stabilization procedures. Greater-level evidence is needed to better evaluate the overall efficacy of this procedure in addressing patellar instability.

Level of Evidence

Level of Evidence, IV; Systematic review of level III and IV studies.

Traumatic Patellar Dislocations in Childhood and Adolescents

Patellar instability and associated patellar dislocation can result in significant pain, disability, and associated injuries in young athletes. The patellofemoral joint is a complex articulation with stabilizing restraints, both medially and laterally, that help guide the patella into the corresponding trochlear groove as the knee cycles through an extension-to-flexion arc. In addition to soft tissue injuries, many osseous aberrancies can contribute to patellar instability in young athletes, including trochlear dysplasia, patella alta, and axial and coronal plane abnormalities. There is a role for nonoperative treatment in these young athletes; however, if recurrent or associated injuries are identified surgical intervention is warranted. Correct diagnosis of the underlying cause of the patellar instability is paramount to developing a surgical plan that will yield the most favorable outcome for these young athletes.

Sulcus Deepening Trochleoplasty and Medial Patellofemoral Ligament Reconstruction for Patellofemoral Instability: A 2-Year Study

PURPOSE

To evaluate outcome data of patients undergoing DeJour sulcus-deepening trochleoplasty with medial patellofemoral ligament reconstruction (MPFLR) for high-grade trochlear dysplasia at a single institution in the United States.

METHODS

A total of 67 patients (76 knees) with severe trochlear dysplasia and recurrent patellar instability were prospectively enrolled and underwent DeJour sulcus-deepening trochleoplasty with MPFLR from 2011 to 2019. Inclusion criteria included recurrent lateral patellar instability following failure of conservative treatment with radiographic evidence of severe trochlear dysplasia (DeJour types B or D). Patients with less than 2-year follow-up were excluded. Radiographic analysis, physical examination, clinical follow-up, patient demographics, and patient-reported outcome measures were obtained for all patients at each visit.

RESULTS

Forty patients (44 knees) had complete 2-year or longer follow-up and were included. The majority of patients were female (81.8%) with a mean age of 19.2 years (standard deviation [SD] 6.7; range 13.2-47.0). Follow-up ranged from 2.0 years to 6.8 years (mean 3.6 years, SD 1.35). In total, 45.5% had failed previous surgery for patellar instability. Eight knees developed arthrofibrosis and the overall reoperation rate was 27.3%. No patients had fixation failure and no further surgery was required for instability. The mean preoperative International Knee Documentation Committee score of 50.8 improved to 79.1 (P < .001), and the mean preoperative Kujala score of 56.4 improved to 86.5 (P < .001). Patients reported high satisfaction rates (mean 9.1 of 10). When applicable, 100% of patients returned to work, whereas 84.8% returned to sport. There was no significant radiographic progression of patellofemoral arthritis at a mean of 2.4 years after surgery (SD 1.7).

CONCLUSIONS

DeJour sulcus-deepening trochleoplasty combined with MPFLR and used with tibial tubercle osteotomy and lateral release is a reliable and effective treatment for recurrent patellar instability due to severe trochlear dysplasia, even in this group with many revisions of previous procedures.

LEVEL OF EVIDENCE

IV, case series.

Trochleoplasty improves knee flexion angles and quadriceps function during gait only if performed bilaterally

PURPOSE

To investigate if a trochleoplasty increases knee flexion angles and extensor moments in the gait of patients with patellar instability and to compare postoperative gait to a healthy control group.

METHODS

A bilateral dislocation group (6 patients) and a unilateral dislocation group (14 patients) were treated with bilateral and unilateral trochleoplasty, respectively. Kinematics and kinetics of the lower extremity were captured using 3D-gait analysis (VICON, 12 cameras, 200 Hz, plug-in-gait, two force plates). The mean of six trials was computed. The gait cycles were compared pre to postoperatively for each group. The gait of the two groups was compared to each other and the gait of a healthy population (54 knees).

RESULTS

After trochleoplasty, the knee flexion angles and knee extensor moments only increased in the bilateral dislocation group, whereas the gait pattern of the unilateral dislocation group remained unchanged. Compared to the healthy population, the postoperative gait pattern of the bilateral dislocation group did not differ. In contrast, knee flexion angles and extensor moments of the unilateral dislocation group were still lower.

CONCLUSION

In adolescents with bilateral recurrent patellar dislocations, trochleoplasty of both knees increases knee flexion angles and knee extensor moments comparable to normal gait. Unilateral symptomatic patients undergoing a unilateral trochleoplasty did not achieve normal walking. These findings point out that patellar instability should be considered as a bilateral problem, even in patients with unilateral dislocations.

LEVEL OF EVIDENCE

III.

[Trochleoplasty: Surgical technique : Video article]

A 29-year-old physically active patient presented with recurrent right-sided patellar dislocation. Clinical and radiological investigation showed patellar instability with stable cruciate and collateral ligaments, excess internal rotation of the right femur, as well as trochlear dysplasia. Treatment consisted of trochleoplasty in combination with medial patellofemoral ligament reconstruction.

Assessing Femoral Trochlear Morphologic Features on Cross-Sectional Imaging Before Trochleoplasty: Dejour Classification Versus Quantitative Measurement

OBJECTIVE. The purpose of this study is to assess the use of cross-sectional imaging to qualitatively and quantitatively categorize trochlear dysplasia as low grade (type A) or high grade (types B-D) according to the Dejour classification. MATERIALS AND METHODS. A retrospective review of CT and MRI knee examinations performed before patients underwent deepening trochleoplasty was independently conducted by two musculoskeletal radiologists. Each case of trochlear dysplasia was qualitatively assigned a Dejour type. Subsequently, quantitative measurements of the sulcus angle, distance from the tibial tubercle to the trochlear groove, trochlear depth, lateral trochlear inclination, trochlear facet asymmetry, and degree of patellar lateralization were performed. RESULTS. A total of 35 patients (29 female patients and six male patients; mean age, 21.1 years) with 39 affected knees (17 right knees and 22 left knees) were included. Readers had exact qualitative agreement using Dejour classification for 30 of 39 knees (77% [κ = 0.77; 95% CI, 0.62-0.91]) and agreement on classification of low-grade versus high-grade dysplasia for 36 of 39 knees (92%). For these 36 knees, the mean differences in measurements of low- versus high-grade dysplasia, respectively, were as follows: for sulcus angle, 153° versus 168° (p < 0.001); for trochlear depth, 4 versus 1 mm (p < 0.001); for lateral trochlear inclination, 12 versus 7 mm (p < 0.02); and for decreased trochlear facet asymmetry, 13% versus 92% (p < 0.001). Trochlear depth, lateral trochlear inclination, and trochlear facet asymmetry were also different in comparisons of knees with Dejour type B and C trochlear dysplasia versus those with Dejour types B and D (all p < 0.05). No quantitative measurement differentiated between trochlear dysplasia of Dejour types C and D. The distance from the tibial tubercle to the trochlear groove and the degree of patellar lateralization were not statistically different between low- and high-grade dysplasia. CONCLUSION. Qualitative use of the Dejour classification accurately categorizes trochlear dysplasia as low grade or high grade in 92% of cases, with exact agreement reached in 77% of cases. Furthermore, the trochlear depth, lateral trochlear inclination, trochlear facet asymmetry, and sulcus angle can differentiate between low-grade and high-grade dysplasia, with trochlear depth, lateral trochlear inclination, and trochlear facet asymmetry useful for differentiating between Dejour types B and C and Dejour types B and D.

Anteroposterior distance between the tibial tuberosity and trochlear groove in patients with patellar instability

BACKGROUND

Our objective was to describe a measurement to assess sagittal tibial tuberosity (TT)-trochlear groove (TG) distance and to compare this between asymptomatic (control) patients and patients with symptomatic patellar instability.

METHODS

We compared static CT images of 22 fully extended knees of patients with symptomatic patellar instability with images of 22 asymptomatic knees. TT-TG distance was measured to quantify lateralization of the TT, and anteroposterior TT-TG distance was used to quantify the sagittal distance between these two points. Lateral trochlear inclination, sulcus angle, and trochlear depth were measured. Groups were compared using paired t tests (alpha = 0.05). Correlations of anteroposterior TT-TG distance with lateral trochlear inclination, sulcus angle, and trochlear depth were assessed using linear and multivariate regression.

RESULTS

Mean TT-TG distances were 19.9 ± 4.4 mm (symptomatic) and 16.8 ± 5.5 mm (control) (mean ± std deviation) (P = 0.002). Mean anteroposterior TT-TG distances were 8.3 ± 7.8 mm (symptomatic) and -0.5 ± 4.6 mm (control) (P < 0.0001). The symptomatic group had greater measurements of trochlear dysplasia, with lower lateral trochlear inclination, greater sulcus angle, and lower trochlear depth (all P < 0.0001). Anteroposterior TT-TG distance and trochlear depth were strongly negatively correlated (r = 0.62, R² = 0.39, P < 0.0001).

CONCLUSIONS

In asymptomatic patients, the anteroposterior TT-TG distance was -0.5 mm, indicating that the TG and TT were nearly in the same coronal plane. In patients with symptomatic patellar instability, the TG was almost nine millimeters anterior, and this distance correlated with measurements of trochlear dysplasia.

LEVEL OF EVIDENCE

III, case control study.

Trochleoplasty provides good clinical outcomes and an acceptable complication profile in both short and long-term follow-up

PURPOSE

The purpose of this study is to report on the global distribution and clinical outcomes of published articles related to trochleoplasty.

METHODS

The online databases OVID Medline, OVID EMBASE, and the Cochrane Library were searched for the literature assessing trochleoplasty performed for lateral patellofemoral instability (LPI). Study data were abstracted looking at global trends in the literature, as well as clinical and patient-reported outcomes following this technique.

RESULTS

For the assessment of global distribution, 29 studies including 998 patients met the inclusion criteria. The majority of the studies were conducted in Europe (93%) and most used an open thin flap technique (52%). For the secondary analysis of clinical outcomes, 21 studies were included with significant heterogeneity in patient selection, reporting on the degree of trochlear dysplasia, and patient-reported outcomes. All trochleoplasty techniques showed statistically significant improvement in clinical outcomes at average 50 months (range 3-228 months) post-operative, with most patients being satisfied with their procedure. Re-dislocation and complication rates were low.

CONCLUSIONS

European centers have published majority of data on trochleoplasty surgery, which has been shown to be an acceptable procedure for patients with high-grade trochlear dysplasia and LPI. Trochleoplasty has demonstrated good clinical outcomes, a low re-dislocation rate, and an acceptable complication profile in both short and long-term follow-up. This study highlights the difficulty in reporting outcomes in this group of patients due to heterogeneity in patient selection, grading of trochlear dysplasia, and the lack of disease-specific outcome measures.

LEVEL OF EVIDENCE

IV.

Deepening trochleoplasty and medial patellofemoral ligament reconstruction normalize patellotrochlear congruence in severe trochlear dysplasia

AIMS

The aim of this study was to evaluate cartilaginous patellotrochlear congruence and patellofemoral alignment parameters after deepening trochleoplasty in severe trochlear dysplasia.

PATIENTS AND METHODS

The study group comprised 20 patients (two male, 18 female; mean age 24 years (16 to 39)) who underwent deepening trochleoplasty and medial patellofemoral ligament (MPFL) reconstruction for the treatment of recurrent lateral patellar dislocation due to severe trochlear dysplasia (Dejour type B to D). Pre- and postoperative MRI investigations of the study group were compared with MRI data of 20 age- and gender-matched control patients (two male, 18 female; mean age 27 years (18 to 44)) regarding the patellotrochlear contact ratio, patellotrochlear contact area, posterior patellar edge-trochlear groove ratio, and patellar tilt.

RESULTS

Preoperatively, all parameters in the study group indicated significant patellar malalignment, including a reduced patellotrochlear contact ratio (mean 0.38 (0.13 to 0.59) vs mean 0.67 (0.48 to 0.88); p < 0.001), reduced contact area (mean 128 mm² (87 to 190) vs mean 183 mm² (155 to 227); p < 0.001), increased patellar lateralization (mean 0.82 (0.55 to 1.0) vs mean 0.99 (0.93 to 1.1); p < 0.001) and increased patellar tilt (mean 25.8° (8.1° to 43.0°) vs mean 9.1° (0.5° to 16.8°); p < 0.001). Postoperatively, all parameters in the study group improved significantly and reached normal values compared with the control group. The patellotrochlear contact ratio increased to a mean of 0.63 (0.38 to 0.85) (p < 0.001), the contact area increased to a mean of 187 mm² (101 to 255) (p < 0.001), the posterior patellar edge-trochlear groove ratio improved to a mean of 0.96 (0.83 to 0.91) (p < 0.001), and the patellar tilt decreased to a mean of 13.9° (8.1° to 22.1°) (p < 0.001) postoperatively.

CONCLUSION

Deepening trochleoplasty and MPFL reconstruction normalized the patellotrochlear congruence and patellofemoral alignment parameters. Modifying the dysplastic trochlea involves approximating the trochlear morphology to the shape of the patella rather than inducing a patella and trochlea mismatch. Cite this article: Bone Joint J 2019;101-B:325-330.

A combined procedure with Bereiter-type trochleoplasty leads to a stable patellofemoral joint at 5-year follow-up

PURPOSE

Trochlear dysplasia is a major risk factor predisposing to patellar instability and has been reported to occur in up to 85% of patients with recurrent patellar dislocation. Different operative techniques have been described to correct trochlear dysplasia, including the Bereiter technique, in which subchondral bone is removed and the cartilage can be compressed into a U-shaped groove. The hypothesis was that after a Bereiter-type trochleoplasty combined with medialisation of the tibial tubercle and MPFL reconstruction, patellar pain and instability decreased and anatomic reconstruction can be seen radiographically after 5-year follow-up.

METHODS

Between 2004 and 2011, a combined procedure including Bereiter-type trochleoplasty was performed on 21 consecutively included patients (22 knees) with objective patellar instability and severe trochlear dysplasia. Instability and pain were assessed preoperatively and 3, 6, 12, 24 and 60 months postoperatively with the visual analogue scale (VAS) for pain and instability, Kujala, International Knee Documentation Committee Subjective Knee Evaluation (IKDC SKE) and Short Form Health Survey (SF-36). Pre- and postoperatively, a true lateral radiograph was made to investigate the presence of the crossing sign and to measure the trochlear bump and trochlear depth, as well as a sunrise patella view to measure the sulcus angle.

RESULTS

VAS pain and instability, Kujala and IKDC SKE improved significantly 5 years after trochleoplasty (p < 0.05). SF-36 showed no significant improvement. None of the patients reported patellar dislocations postoperatively. Sport activities remained limited. Postoperative radiographs showed no crossing sign. There was a significant increase in trochlear depth (p < 0.0001) and also a significant decrease in trochlear bump and sulcus angle (both p < 0.0001).

CONCLUSIONS

A combined procedure consisting of Bereiter-type trochleoplasty, medialisation of the tibial tubercle and MPFL reconstruction in patients with objective patellar instability and severe trochlear dysplasia resulted in a clear decrease of pain and instability. Radiological assessment showed anatomical reconstruction. Nevertheless, residual symptoms remain and the possibility of future cartilage damage is uncertain.

LEVEL OF EVIDENCE

IV.

Patellar Instability Management: A Survey of the International Patellofemoral Study Group

BACKGROUND

Although patellofemoral instability is among the most prevalent knee disorders, the management of patients with this condition is complex and remains variable, given the lack of long-term, high-level clinical outcome studies to compare various operative and nonoperative modalities.

PURPOSE

To discover a consensus within treatment controversies in patellofemoral instability among experienced knee surgeons with a specific interest in the patellofemoral joint.

STUDY DESIGN

Expert opinion; Level of evidence, 5.

METHODS

A 3-step modified Delphi technique was used to establish a consensus. A 34-question, case-based online survey regarding patellofemoral instability was distributed to all active members of the International Patellofemoral Study Group. Consensus statements were generated if at least 66% of the respondents agreed and then redistributed to the same panel. Modifications to the consensus statements were made based on the iterative feedback process until no discordance was encountered in the third stage.

RESULTS

Eight consensus statements were achieved. Nonoperative management is the current standard of care for a first-time dislocation in the absence of an osteochondral fragment or loose body requiring excision (100% agreement). In patients with a first-time dislocation with an operative osteochondral fracture requiring excision or repair, patellar instability should be addressed concurrently (89% agreement). Recurrent instability should be treated surgically, with most surgeons favoring medial reconstruction (77%-86% agreement). While there is general agreement that bony procedures should be performed to correct underlying bony deformities, there is no consensus regarding the most appropriate type of procedure performed. Lateral release should not be performed in isolation for the treatment of patellar instability (89% agreement).

CONCLUSION

Despite the consensus generated in this study, our current understanding remains limited by a lack of high-level evidence as well as the numerous complex variables influencing treatment decision making. High-quality, multicenter randomized controlled trials, particularly those directly comparing specific surgical treatment methods while controlling for underlying risk factors, are needed to address these areas of uncertainty.

Trochleoplasty: Indications and Technique

PURPOSE OF REVIEW

Trochlear dysplasia is a well-described risk factor for patellar instability. Trochleoplasty has emerged as a procedure within the surgical armamentarium for patellar instability, yet its role is unclear. A variety of trochleoplasty procedures have emerged. The purpose of this review is to clarify indications for trochleoplasty, outline the technical steps involved in performing common trochleoplasties and report the published outcomes and potential complications of these procedures.

RECENT FINDINGS

Patellar instability with severe trochlear dysplasia is the main indication for trochleoplasty. Three types of trochleoplasty have emerged: (1) lateral facet elevation; (2) sulcus deepening; and (3) recession wedge. Deepening and recession wedge trochleoplasties are the most commonly performed. Trochleoplasty is a surgical option for addressing patellar instability in patients with severe trochlear dysplasia. Deepening and recession wedge trochleoplasties that address Dejour B and D dysplastic trochleas are the most studied, with both short- and midterm outcomes reported. Long-term outcomes are lacking and comparative studies are needed.

Trochlear dysplasia: imaging and treatment options

Recurrent patellar dislocation is a disabling condition, which can lead to articular cartilage injuries, osteochondral fractures, recurrent instability, pain, decreased activity and patellofemoral osteoarthritis. Trochlear dysplasia represents an important component of patellar dislocation.

Imaging provides an objective basis for the morphological abnormalities and thus allows determination of the surgical strategy according to the concept of ‘à la carte’ surgery.

The main surgical techniques of trochleoplasty are the sulcus deepening trochleoplasty, the ‘Bereiter’ trochleoplasty and the recession trochleoplasty.

At mid-term, all techniques have shown a postoperative improvement in clinical scores, with a low rate of recurrence of dislocation and a possible return to sport. But these techniques do not halt the progression of patellofemoral arthritis.

Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170058

Deepening trochleoplasty combined with balanced medial patellofemoral ligament reconstruction for an adequate graft tensioning

AIM

To evaluate our modified deepening trochleoplasty combined with a balanced medial patellofemoral ligament (MPFL) reconstruction for soft tissue alignement.

METHODS

Thirty-three knees with with recurrent patellar dislocations and a trochlear dysplasia in 30 patients (m/f = 12/21, mean age 24 ± 9 years) underwent a combination of a modified deepening trochleoplasty and a balanced MPFL reconstruction for a medial soft tissue alignement. After a mean follow-up period of 29 ± 23 mo, patients’ return to sports, possible complications as well as the clinical outcomes using the Kujala, International Knee Documentation Committee (IKDC) and Lysholm scoring were evaluated. Moreover, patients’ satisfaction with the general outcome, the cosmetic outcome, the pre- and postoperative pain and a potential avoidance behaviour were assessed with additional standardized questionnaires which also included different visual analog scales.

RESULTS

There were no signs of a persistent instability. The Kujala score improved from a mean of 64 ± 16 points to 94 ± 9 points, the Lysholm score improved from a mean of 63 ± 17 to 95 ± 6 points and the IKDC score from 58 ± 11 to 85 ± 12 points, P < 0.0001, respectively. The assessment of pain using a visual analog scale showed a significant pain reduction from a mean of 4.8 ± 2.0 to 1.3 ± 3.4 points (P < 0.0001). Two of 26 cases (92%) who were engaged in regular physical activity before surgery did not return to full sporting activities. One patient felt that his sport was too risky for his knee and reported an ongoing avoidance behaviour. The other patient preferred to wait for surgery of her contralateral knee. Of the eight patients who were not engaged in sporting activities before surgery, three started regular sporting activities after surgery. In 31 of the 33 cases (94%), the patients were very satisfied with the clinical outcome of the surgery. Regarding the cosmetic results, no patients felt impaired in their self-confidence and in their clothing decisions.

CONCLUSION

Our technique shows a good clinical outcome in terms of the common scorings as well as in terms of pain, return to sports and patient satisfaction.