Femoral trochleoplasty for recurrent patellar instability: a modified surgical technique and its medium-term results

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.

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.

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.

Trochleoplasty procedures show complication rates similar to other patellar-stabilizing procedures

PURPOSE

Trochleoplasty aims to restore patellar stability. Various techniques have been described and almost all authors report successful results. However, the procedure has a significant risk of complications. Purpose of this study was to perform a systematic review and meta-analysis of the available literature to assess the rate of complications after the various techniques used for trochleoplasty procedures.

MATERIALS AND METHODS

MEDLINE, EMBASE, Web of Science and Cochrane Library databases were searched. Studies on patients with recurrent patellar instability treated with a trochleoplasty with or without additional procedure, and reported complications were included. The primary outcome was the rate of complications per technique. A meta-analysis was performed whenever three or more studies per surgical technique could be included.

RESULTS

The selection process resulted in 20 studies included for analysis. A lateral facet elevating trochlear osteotomy was reported by two studies, ten studies reported on a Bereiter trochleoplasty, five on a Dejour trochleoplasty, one on an arthroscopic technique, one on a 'modified' technique and one on a recession wedge trochleoplasty. Meta-analysis showed that proportion of recurrent dislocation was 0.04 (95% CI 0.02-0.07) for Bereiter trochleoplasty and 0.02 (95% CI 0-0.08) for Dejour trochleoplasty. These proportions were 0.06 (95% CI 0.02-0.13) and 0.09 (95% CI 0.03-0.27) for recurrent instability, 0.07 (95% CI 0.02-0.19) and 0.12 (95% CI 0.00-0.91) for patellofemoral osteoarthritis and 0.08 (95% CI 0.04-0.14) and 0.20 (95% CI 0.11-0.32) for further surgery respectively.

CONCLUSION

This study demonstrates that the complications after a Bereiter and Dejour trochleoplasty including additional procedures are in the range of those of other patellar stabilizing procedures. For four other techniques, no meta-analysis could be performed. The clinical relevance of this study is that it provides clinicians with the best currently available evidence on the rate of complications after trochleoplasty procedures. This can be helpful in the process of deciding whether or not to perform such a procedure, and can be used to better inform patients about the advantages and disadvantages of different trochleoplasty procedures.

LEVEL OF EVIDENCE

Level IV.

Surgical treatment of patellofemoral instability using trochleoplasty or MPFL reconstruction: a systematic review

PURPOSE

Trochleoplasty and reconstruction of the medial patellofemoral ligament (MPFL) are among the most commonly performed surgical treatments in patients with patellofemoral instability. The primary purpose of the study was to perform a systematic literature review on trochleoplasty in the treatment of patients with patellofemoral instability. The secondary purpose was to compare the outcomes with those seen in patients treated after reconstruction of the MPFL.

METHODS

A standardised search on search engines was performed. All observational and experimental studies dealing with trochleoplasty were then obtained and reviewed in a consensus meeting. Fifteen articles out of 1543 were included and analysed using the CASP appraisal scoring system. Twenty-five studies on MPFL reconstruction were obtained for comparison. The clinical and radiological outcomes were statistically analysed.

RESULTS

Both treatment groups showed significant improvement in outcomes from pre- to post-operatively. The mean post-operative Kujala and the Lysholm scores significantly increased in both groups when compared to preoperatively (trochleoplasty group: Kujala 61.4-80.8 and Lysholm 55.5-78.5; MPFL group: Kujala 46.9-88.8 and Lysholm 59.9-91.1). Post-operatively a positive apprehension test was found in 20 and 8 % of the trochleoplasty and MPFL groups, respectively. No significant differences in redislocation (2 %) and subluxation (5-6 %) rates were found.

CONCLUSIONS

This systematic review showed that both trochleoplasty and MPFL reconstruction are able to deliver good clinical outcomes with stable patellofemoral joints.

LEVEL OF EVIDENCE

III.

Trochleoplasty as a Solitary Treatment for Recurrent Patellar Dislocation Results in Good Clinical Outcome in Adolescents

BACKGROUND

The essential static patellar stabilizer is a normal-shaped trochlear groove. A dysplastic groove destabilizes the patella. Trochleoplasty approaches this underlying condition and reshapes the trochlea. However, studies have reported on trochleoplasty for revision cases or as accompanied by other interventions. The effect of trochleoplasty alone remains unexplained.

PURPOSE

To introduce trochleoplasty as a stand-alone treatment for recurrent patellar dislocation and to compare its pre- to postoperative functional and clinical variables.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A trochleoplasty was performed in 50 knees (27 right) in 44 patients (30 females; mean ± SD age, 15.6 ± 2.0 years). The indication for surgery was recurrent patellar dislocation not responding to nonoperative treatment (>6 months), with types B through D dysplasia and closed or closing physes in adolescents aged 10 to 20 years. Assessment included J-sign and apprehension test, Kujala and Lysholm scores, patients' subjective assessment and activity level according to the International Knee Documentation Committee questionnaire, and patients' overall satisfaction. The Caton-Deschamps ratio and the lateral condyle index were measured. Pre- versus postoperative values were compared with a paired Wilcoxon signed-rank test. The minimum follow-up was 24 months (33 ± 10.6 months).

RESULTS

The Kujala score improved from 71 preoperatively to 92 postoperatively (P < .001) and the Lysholm score from 71 to 95 (P < .001). Patients' subjective assessment improved at the final follow-up as compared with that preoperatively (P < .001). Most patients enhanced their activity (P < .001), and their overall satisfaction increased postoperatively (P < .001). Preoperatively, there was a positive J-sign in 45 knees and a positive apprehension test in 41 knees. Both markers disappeared postoperatively in 39 and 33 knees, respectively, leaving 6 knees with a positive J-sign and 8 knees with a positive apprehension test (P < .001). One patella redislocated postoperatively after 38 months. Four patients required a single arthroscopic debridement.

CONCLUSION

In this study, trochleoplasty as a solitary treatment for recurrent patellofemoral dislocations in patients with trochlear dysplasia resulted in good clinical outcomes if severe torsional and axial malalignment was excluded. Kujala and Lysholm scores increased postoperatively, as well as subjective International Knee Documentation Committee assessment of outcomes, activity level, and overall satisfaction.

Sulcus deepening trochleoplasty for patellofemoral instability: A series of 34 cases after 15 years postoperative follow-up

INTRODUCTION

Trochlear dysplasia is one of the main elements of patellofemoral instability. Although correction by trochleoplasty seems logical, the long-term outcome of this procedure is unknown and the progression to osteoarthritis has not been clarified. Thus, we performed a retrospective study of a series of sulcus deepening trochleoplasties with a 15-year follow-up whose goal was to (1) evaluate the long-term clinical outcome and radiological rate of osteoarthritis, and (2) define the results in relation to the type of instability and the grade of dysplasia.

HYPOTHESIS

Sulcus deepening trochleoplasty is an effective procedure to stabilize the patellofemoral joint that does not increase the risk of osteoarthritis.

PATIENTS AND METHODS

This retrospective study analyzed 34 sulcus deepening trochleoplasties based on clinical scores (IKS, Lille, Kujala and Oxford scores) and radiological results (stage of osteoarthritis according to the Iwano score) after a mean follow-up of 15 years (12-19 years). An Insall procedure was systematically associated with an anterior tibial tubercle transfer in 17 cases (7 prior tibial transfers).

RESULTS

No recurrent objective instability was observed. Seven knees had additional surgery after a mean follow-up of 7 years (2-16): 7 underwent conversion to total knee arthroplasty because of progression of osteoarthritis and one knee had tibial tubercle transfer for pain and episodes of the knee giving way. The mean Lille, Kujala and IKS scores increased from 53.3 (30-92), 55 (13-75) and 127 (54-184) to 61.5 (25-93), 76 (51-94) and 152.4 (66-200) respectively between preoperative and follow-up assessment (P<0.05) (revisions included). Functional outcome was significantly better for dysplasia with supratrochlear spurs (IKS score 168 [127-200] versus 153 [98-198] and Kujula score 81.5 [51-98] versus 76 [51-94] [P<0.05]). Patients were satisfied in 65% of the cases and the total mean Oxford score was 24.1/60 (12-45 points). Occasional pain was present in 53% of the cases. The trochlear prominence decreased from 4.9 mm (3-9 mm) to -1.2mm (-7-4mm). Ten cases of preoperative patellofemoral osteoarthritis were identified, but none with>Iwano 2, while osteoarthritis was present in 33/34 cases at the final follow-up with 20 cases>Iwano 2 (65%).

DISCUSSION

Sulcus deepening trochleoplasty corrects patellofemoral stability even in patients with severe dysplasia and the long-term functional outcome is better in this group. It does not prevent patellofemoral osteoarthritis. It should be limited to severe dysplasia with supratrochlear spurs and associated with procedures to realign the extensor apparatus.

Trochlear dysplasia and the role of trochleoplasty

The diagnosis and treatment of chronic patellar instability caused by trochlear dysplasia can be challenging. A dysplastic trochlea leads to biomechanical and kinematic changes that often require surgical correction when symptomatic. In the past, trochlear dysplasia was classified using the 4-part Dejour classification system. More recently, new classification systems have been proposed. Future studies are needed to investigate long-term outcomes after trochleoplasty.

The role of trochlear dysplasia in patellofemoral instability

Trochlear dysplasia is characterized by abnormal trochlear morphology and a shallow groove. It is associated with recurrent patellar dislocation, but it is unclear whether the dysplasia is congenital, the result of lateral tracking and chronic instability, or caused by a combination of factors. Lateral radiographs elucidate the crossing sign and characteristic trochlear prominence. Recurrent patellofemoral instability is multifactorial, and each component must be considered in determining treatment. Managing other factors associated with recurrent instability may compensate for a deficient trochlea and provide stability. Medial patellofemoral ligament reconstruction is recommended for patellofemoral instability in the presence of trochlear dysplasia in patients without patella alta or increased tibial tubercle-trochlear groove distance. Trochleoplasty should be reserved for severe dysplasia in which patellofemoral stability cannot otherwise be obtained.