Combined arthroscopic deepening trochleoplasty and reconstruction of the medial patellofemoral ligament for patients with recurrent patella dislocation and trochlear dysplasia

Good short-term results following arthroscopic deepening trochleoplasty combined with medial patellofemoral ligament reconstruction: surgical technique and outcomes

PURPOSE

To report short-term results and clinical outcomes of arthroscopic deepening trochleoplasty combined with medial patellofemoral ligament (MPFL) reconstruction utilizing standard arthroscopic instruments in patients of recurrent patellar dislocation and trochlear dysplasia.

METHODS

This is a case series of 13 patients between the ages of 14 and 20 years who presented with recurrent patellar dislocation and severe trochlear dysplasia (Dejour grade D). They were treated surgically using an arthroscopic technique from February 2017 to January 2019 and were followed for 18 months. Patients were assessed preoperatively and postoperatively (at 6, 12, and 18 months) with clinical scores (Tegner Activity Score, Lysholm Knee Score, and Kujala Score).

RESULTS

There were 69.2% females, and the mean age was 16.4 ​± ​2.0 years. There were statistically significant improvements in the mean Lysholm and Kujala scores when comparing pre-operative and post-operative scores at every follow-up landmark (p ​< ​0.05). Comparing the preoperative and 18-month postoperative scores-the Lysholm score improved from 68.2 ​± ​10.3 to 98.7 ​± ​2.1 (p ​< ​0.001), and the Kujala score improved from 50.3 ​± ​12.0 to 95.4 ​± ​4.8 (p ​< ​0.001). Five patients were able to achieve premorbid Tegner activity levels at 12 months, with an additional 5 patients achieving the same premorbid Tegner activity at the 18-month mark. The remaining 3 patients were able to attain >90% of their activity level at 18 months' follow-up. No complications were observed during the follow-up period.

CONCLUSIONS

This proposed arthroscopic deepening trochleoplasty technique combined with MPFL reconstruction has demonstrated excellent and reproducible early clinical outcomes.

LEVEL OF EVIDENCE

IV.

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 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.

Adductor Canal Block Combined with General Analgesia for Patients with Recurrent Patellar Dislocation Undergoing "3-in-1" Procedure Surgery: A Prospective Randomized Controlled Trial

OBJECTIVE

Patellar dislocation is a common injury in sports medicine. While surgical treatment is an important option, pain is severe after surgery. This study compared the analgesic effect and early rehabilitation quality between adductor canal block combined with general analgesia (ACB + GA) and single general analgesia (SGA) after recurrent patellar dislocation (RPD) for "3-in-1" procedure surgery.

METHODS

From July 2018 to January 2020, a prospective randomized controlled trial was conducted in analgesia management after RPD for "3-in-1" procedure surgery. The 40 patients in the experimental group received ACB (0.3% ropivacaine 30 mL) + GA, while the 38 patients in the control group received SGA. Patients in both groups received "3-in-1" procedure surgery, standardized anesthesia, and analgesia during hospitalization. The outcomes included the visual analog scale (VAS), quadriceps strength, Inpatient Satisfaction Questionnaire (IPSQ), Lysholm scores, and Kujala scores. Total rescue analgesic consumption and adverse events were also recorded. One-way analysis of variance (ANOVA) was used to compare continuous variables between groups and chi-square or Fisher's exact tests were used to compare count data. Nonparametric Kruskal-Wallis H tests evaluated ranked data.

RESULTS

No significant differences in resting VAS scores were observed at 8, 12, and 24 h postoperatively. However, the flexion and moving VAS scores of the ACB + GA group were significantly lower than those of the SGA group (p < 0.05). Meanwhile, the first triggering of rescue analgesics was advanced in the SGA group (p < 0.0001), and the dose of opioid analgesics was significantly higher (p < 0.0001). The quadriceps strength of the ACB + GA group was higher than that of the SGA group at 8 h postoperatively. The IPSQ of the ACB + GA group was significantly higher 24 h postoperatively. We observed no significant differences in Lysholm and Kujala scores between the two groups at 3 months after surgery.

CONCLUSIONS

Early analgesia management of ACB + GA showed excellent analgesia effectiveness and a positive hospitalization experience for RPD patients undergoing "3-in-1" procedure surgery. Moreover, this management was good for early rehabilitation.

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.

Surgical treatment of patellar dislocation: A network meta-analysis of randomized control trials and cohort studies

Background

Currently, there are many surgical options for patellar dislocation. The purpose of this study is to perform a network meta-analysis of the randomized controlled trials (RCTs) and cohort studies to determine the better treatment.

Method

We searched the Pubmed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, clinicaltrials.gov and who.int/trialsearch. Clinical outcomes included Kujala score, Lysholm score, International Knee Documentation Committee (IKDC) score, redislocation or recurrent instability. We conducted pairwise meta-analysis and network meta-analysis respectively using the frequentist model to compare the clinical outcomes.

Results

There were 10 RCTs and 2 cohort studies with a total of 774 patients included in our study. In network meta-analysis, double-bundle medial patellofemoral ligament reconstruction (DB-MPFLR) achieved good results on functional scores. According to the surface under the cumulative ranking (SUCRA), DB-MPFLR had the highest probabilities of their protective effects on outcomes of Kujala score (SUCRA 96.5 %), IKDC score (SUCRA 100.0%) and redislocation (SUCRA 67.8%). However, DB-MPFLR (SUCRA 84.6%) comes second to SB-MPFLR (SUCRA 90.4%) in Lyshlom score. It is (SUCRA 70%) also inferior to vastus medialis plasty (VM-plasty) (SUCRA 81.9%) in preventing Recurrent instability. The results of subgroup analysis were similar.

Conclusion

Our study demonstrated that MPFLR showed better functional scores than other surgical options.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

V.

Versorgungsrealität patellastabilisierender Operationen

Hintergrund

Die patellofemorale Instabilität zählt zu den häufigsten Pathologien des Kniegelenks. Die Planung und Durchführung patellastabilisierender Operationen ist sehr variabel. Bezüglich der operativen Maßnahmen kommt der präoperativen Planung, gerade im Hinblick auf die häufig hohe Komplexität der zugrundeliegenden Pathologien, eine entscheidende Bedeutung zu.

Fragestellung

Ziel dieser Studie war es, die aktuelle Versorgungsrealität in Bezug auf Planung und Durchführung patellastabilisierender Operationen unter Mitgliedern der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU) abzubilden. Des Weiteren sollte erhoben werden, ob ggf. automatisierte Analysen der zugrundeliegenden Anatomie die Planung und Durchführung patellastabilisierender Operationen (im Primär- und Revisionsfall) beeinflussen würden.

Material und Methoden

Unter allen aktiven Mitgliedern der DGOU wurde per Mail eine anonymisierte Online-Umfrage mit 16 Fragen erhoben. 7974 Mitglieder wurden angeschrieben, 393 Rückmeldungen konnten anschließend analysiert werden.

Ergebnisse

Die MPFL-Plastik (89,8 %) ist die am häufigsten durchgeführte Operation zur Patellastabilisierung. Dahinter folgen Tuberositasversatzoperationen (64,9 %), Korrekturosteotomien (51,2 %) und Trochleaplastiken (19,9 %). Die Wahl bezüglich des operativen Vorgehens fällt überwiegend auf Grundlage einer Kombination aus klinischen und radiologischen Befunden (90,3 %). Für die Entscheidung zur Operation werden hauptsächlich MRT-Bildgebung (81,2 %), Standard-Röntgenbilder (77,4 %) und Beinganzaufnahmen (76,6 %) herangezogen. Insgesamt würden 59,3 % der Befragten eine automatisierte Analyse für eine vereinfachte präoperative Planung und die Detektion von entscheidenden radiologischen Parametern (59,0 %) in Anspruch nehmen, sofern diese zur Verfügung stünden.

Diskussion

Die Erhebungen dieser Umfrage unter Mitgliedern der DGOU weisen die MPFL-Plastik als zentralen Ansatzpunkt zur operativen Behandlung patellofemoraler Instabilitäten aus, diagnostisch ist die MRT-Bildgebung essenziell. Durch eine zukünftige Etablierung automatisierter Software-gestützter Analysemethoden könnte bei einer Vielzahl von Operateuren eine Erweiterung der radiologisch berücksichtigten Parameter in der Planung patellastabilisierender Operationen erreicht werden.

Return to Sport After Medial Patellofemoral Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

Patellar instability is frequently encountered in the athletic population. Medial patellofemoral ligament (MPFL) reconstruction is a common strategy to treat recurrent patellar dislocation and demonstrates good clinical outcomes.

PURPOSE/HYPOTHESIS

The purpose was to examine return to sport after MPFL reconstruction for patellar instability. We hypothesized that patients would resume athletic activity at a high rate and that a large proportion would return to their preoperative level of performance.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review of the literature was conducted using PubMed and Cochrane Library databases to identify articles reporting return to sport after MPFL reconstruction for recurrent patellar dislocation. Athletes were defined as those reporting a preoperative sport. A random-effects model was used to evaluate return to sport rates, subsequent level, and rate of instability recurrence. Meta-regression was used to compare return to sport rates in patients undergoing MPFL reconstruction without osteotomy compared with those treated with simultaneous tibial tubercle osteotomy or trochleoplasty.

RESULTS

In total, 23 articles met inclusion criteria after full-text review. A total of 930 patients were analyzed, including 786 athletes. Women represented 61.3% of all patients. The overall mean age was 21.1 years (range, 9.5-60.0 years), with a mean follow-up time of 3.0 years (range, 0.8-8.5 years). The return to sport rate was 92.8% (95% CI, 86.4-97.6). Patients returned to or surpassed their preoperative level of activity in 71.3% (95% CI, 63.7-78.4) of cases. An osteotomy was performed on 10.5% of athletes. Return to sport did not differ significantly in patients undergoing MPFL reconstruction without osteotomy versus those receiving additional osteotomy (95.4% vs 86.9%; P = .22). Patients returned to sport at a mean of 6.7 months (range, 3.0-6.4 months) postoperatively. Osteotomy did not affect return time. Complications occurred at an overall rate of 8.8%. The most common complication was recurrence of instability (1.9%; 95% CI, 0.4-4.0). The Kujala score was reported by 13 studies, with pre- and postoperative combined means of 60.3 and 90.0, respectively.

CONCLUSION

MPFL reconstruction is an effective and reliable treatment in the setting of patellofemoral instability. Surgeons can counsel their patients that they can expect a high rate of return to sport after MPFL reconstruction surgery alone or with concomitant osteotomy.

[Trochleoplasty as a treatment option for recurrent patellofemoral instability]

Chronic patellofemoral instability (PFI) is a multifactorial condition. Trochlear dysplasia is present in 85-96 % of patients with PFI 7. The technique of trochleoplasty introduced in this article represents a causal treatment option and shows promising results. However, as the indication depends on image-morphological, clinical and functional factors, all other risk factors of PFI should always be considered and evaluated.

Trochlear Dysplasia: When and How to Correct

When? Only patients with high-grade trochlear dysplasia types B and D, in which the prominence of the trochlea (supratrochlear spur) is over 5 mm, recurrent patellar dislocation, and maltracking. How? Sulcus deepening trochleoplasty: modifies the trochlear shape with a central groove and oblique medial and lateral facets; decreases the patellofemoral joint reaction force by reducing the trochlear prominence (spur); and reduces the tibial tubercle and the trochlear groove value by a proximal realignment. Pros: This procedure is highly effective in restoring patellofemoral stability and satisfying the patients. Cons: The patients must be aware of the risk of continuing residual pain and range-ofmotion limitation and that the development of patellofemoral osteoarthritis is not predictable.

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.

Treatment of Proximal Trochlear Dysplasia in the Setting of Patellar Instability: An Arthroscopic Technique

Patellar instability is a complex disorder with multiple etiologies, and treatment must be individualized to the unique pathoanatomy of each patient. Medial patellofemoral ligament reconstruction is one of the most commonly performed procedures for the treatment of patellar instability. Patients with a symptomatic supratrochlear spur, defined by the presence of a "jumping" J sign on examination, also may benefit from an adjunctive proximal trochlear resection. Here, we describe a technique for an arthroscopic proximal trochlear resection, or "bumpectomy," involving resection of the supratrochlear spur. In appropriately indicated patients, we have found this procedure to be a useful adjunct to medial patellofemoral ligament reconstruction without the need for concurrent trochlear sulcus deepening.

Conservative versus tailored surgical treatment in patients with first time lateral patella dislocation: a randomized-controlled trial

Background

Patellar instability has a high incidence and occurs particularly in young and female patients. If the patella dislocates for the first time, treatment is usually conservative. However, this cautious approach carries the risk of recurrence and of secondary pathologies such as osteochondral fractures. Moreover, there is also risk of continuous symptoms apparent, as recurrent patella dislocation is related to patellofemoral osteoarthritis as well. An initial surgical treatment could possibly avoid these consequences of recurrent patella dislocation.

Methods

A prospective, randomized-controlled trial design is applied. Patients with unilateral first-time patella dislocation will be considered for participation. Study participants will be randomized to either conservative treatment or to a tailored patella stabilizing treatment. In the conservative group, patients will use a knee brace and will be prescribed outpatient physical therapy. The surgical treatment will be performed in a tailored manner, addressing the pathologic anatomy that predisposes to patella dislocation.

The Banff Patellofemoral Instability-Instrument 2.0, recurrence rate, apprehension test, joint degeneration, and the Patella Instability Severity Score will serve as outcome parameters. The main analysis will focus on the difference in change of the scores between the two groups within a 2-year follow-up.

Statistical analysis will use linear mixed models. Power analysis was done for the comparison of the two study arms at 2-year follow-up with regard to the BPII Score. A sample size of N = 64 per study arm (128 overall) provides 80% power (alpha = 0.05, two-tailed) to detect a difference of 0.5 standard deviations in a t-test for independent samples.

Discussion

Although several studies have already dealt with this issue, there is still no consensus on the ideal treatment concept for primary patellar dislocation. Moreover, most of these studies show a unified surgical group, which means that all patients were treated with the same surgical procedure. This is regarded as a major limitation as surgical treatment of patella dislocation should depend on the patient’s anatomic pathologies leading to patellar instability. To our knowledge, this is the first study investigating whether patients with primary patella dislocation are better treated conservatively or operatively with tailored surgery to stabilize the patella.

Trial registration

The study will be prospectively registered in the publicly accessible database www.ClinicalTrials.gov.

Medial patellofemoral ligament reconstruction with and without trochleoplasty for patients with patella instability-correlation of trochlear dysplasia and patient outcome, classification and outcome measure in the past decade-a systematic review

PURPOSE

The primary aim of the study is to compare the patient outcome in medial patellofemoral ligament reconstruction (MPFLR) or MPFLR concurrent with trochleoplasty (MPFLR + TP) and correlate it with the degree of trochlear dysplasia (TD). The secondary aim is to review TD classification, outcome measure, chronological and geographical trend of such studies in the past decade.

METHODS

A systemic review of the literature in the past decade on studies of patients with patella instability and underwent either a MPFLR or MPFLR + TP. The degree of TD with the patient outcome was correlated and compared between the 2 groups. The TD classification, outcome measures, chronological and geographical trends of these studies were documented.

RESULTS

There is no statistical difference in the overall improvement in the compared outcome scores between the 2 groups. However, the MPFLR studies reported a total of 16 re-dislocation in contrast to none in the MPFLR + TP studies. The 24 selected studies in the current review utilized different TD classification as well as outcome measures. A more homogeneous subgroup of 12 studies utilized Dejour classification as well as Kujala score that enabled comparison and showed no significant difference in outcome. The highest number of MPFLR publications was in 2019 and was from North and South Americas, Asia and Europe. The MPFLR + TP studies were from Europe during 2013 to 2017.

CONCLUSION

Though there is an overall improvement in post-operative outcomes scores with no statistical significance between MPFLR and MPFLR + TP, the documented re-dislocations in the MPFLR studies suggested an undetermined zone where the choice of procedure could result in a different outcome. The current review did not show correlation between the degree of TD with the patient outcome to provide a clear indication for either procedure according to the degree of TD. The diverse TD classifications and varied outcome measures indicated the need for standardization and consistency in documentation to guide the treating clinician in the choice of procedure. MPFLR was more commonly performed and studied than MPFLR + TP in the past decade.

Anatomical Medial Patellofemoral Ligament Reconstruction for Recurrent Patella Dislocation: Two-Strand Grafts versus Four-Strand Grafts

The purpose of this study was to describe two anatomical medial patellofemoral ligament (MPFL) reconstruction methods: reconstruction with two-strand grafts and reconstruction with four-strand grafts and to evaluate the clinical and radiological results. From January 2010 to January 2013, patients who sustained recurrent patella dislocation and met inclusion criteria were included in the study and divided into two groups randomly to undergo MPFL reconstruction either by two-strand grafts (T group) or four-strand grafts (F group). Patients were followed up 1 month, 1 year, 2 years, and 3 years postoperatively. The apprehension test was applied to test patella stability. The Kujala score, Lysholm score, and Crosby-Insall grading were used to evaluate the function of the affected knee. The patellar congruence and patellar tilt angle were used to measure the morphology of the patellofemoral joint. In addition, patients' subjective assessments and complications were recorded. Thirty-eight patients in T group and 38 patients in F group were followed for at least 36 months. The apprehension test was positive in all patients preoperatively but was negative at follow-up. The Kujala score, Lysholm score, patellar congruence angle, and the patellar tilt angle of patients in both groups improved significantly at 36-month follow-up when compared with those assessed preoperatively. However, patients in the F group achieved better clinical results in terms of Kujala score, patellar congruence angle, patellar tilt angle, and Crosby-Insall grading when compared with those in the T group 3 years after the operation. Most patients (92% of patients in the T group and 97% of patients in the F group) were satisfied with the surgery. The anatomical MPFL reconstruction with two-strand grafts or four-strand grafts were both safe techniques for recurrent patella dislocation with satisfactory clinical outcomes. The anatomical fixation with four-strand grafts achieved better clinical and radiographic results in the follow-up, which may be a better reconstruction method.

[Patellar dislocation : Causes and treatment]

The causes of patellofemoral instability (PFI) are complex. In accordance with the current literature a classification was developed which clearly weights all entities and derives diagnostic and therapeutic consequences. It considers patellar instability and patellar maltracking or the complete loss of patellar tracking and differentiates into 5 types. Type 1: patellar dislocation without maltracking or instability with a low risk of redislocation. Type 2: high risk of redislocation, no maltracking. Type 3: instability and maltracking; reasons for maltracking are a) soft tissue contracture, b) patella alta, c) pathological tibial tuberosity trochlear groove (TTTG) distance, c) valgus deformities and e) torsional deformities. Type 4: massively unstable floating patella, which is based on a high-grade trochlear dysplasia. Type 5: maltracking without instability.

Prevailing disagreement in the treatment of complex patellar instability cases: an online expert survey of the AGA Knee-Patellofemoral Committee

PURPOSE

To evaluate the current state of knowledge and potential controversies in the treatment of patellofemoral instability among orthopaedic/trauma surgeons in the German-speaking countries.

METHODS

An online survey consisting of 32 questions and three fictitious cases was sent to members of the AGA-Society for Arthroscopy and Joint Surgery. Surgeons were defined by our senior authors as high-volume or low-volume surgeons, depending on the number of their cases. The treatment of 25% of patients with patellofemoral instability and/or the performance of 50 patellofemoral instability cases per year distinguishes high- from low-volume surgeons in this study.

RESULTS

The online questionnaire was completed by 541 experienced knee surgeons from Germany (78%), Austria (10.9%), Switzerland (10.4%) and other countries (0.7%). Most surgeons prefer MPFL reconstruction as surgical intervention in patients with recurrent patellar instability (64-81%). Sixty percent of high-volume surgeons as compared to 21.8% of low-volume surgeons have ever performed a trochleoplasty. Of the overall respondents, 25% would not perform any surgical treatment on adolescents with patellar instability and an open growth plate. Of all responding surgeons, 95% would not treat patellofemoral instability with an isolated lateral release. This corresponds to recent literature showing poor outcome of its strictly isolated application.

CONCLUSION

This study provides an overview of the current management of acute and recurrent patellofemoral instability in the German-speaking countries. Results show the surgeons' awareness for highly demanding surgical possibilities for complex patellar instability cases. However, disagreement among surgeons still prevails when it comes to selecting individual multimodal treatment options. This highlights the need for treatment guidelines and algorithms for patellofemoral instability.

LEVEL OF EVIDENCE

V.

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.

A pre-operative grade 3 J-sign adversely affects short-term clinical outcome and is more likely to yield MPFL residual graft laxity in recurrent patellar dislocation

PURPOSE

The purposes of this study were to investigate the anatomical risk factors of grade 3 J-sign and analyse the influence of J-sign grades on the short-term clinical outcomes of patients with recurrent patellar dislocation.

METHODS

From 2016 to 2018, a total of 168 patients with recurrent patellar dislocation (187 knees) underwent medial patellofemoral ligament reconstruction with or without tibial tuberosity medialization. Pre-operative J-sign severity was graded according to a previously described classification (grades 1-3). Potential anatomical risk factors of J-sign were explored. Comparisons were assessed between patients with different grades of J-sign using univariate and binary logistic regression analyses. The Kujala score was assessed and compared with pre-operative values, and stress fluoroscopy was performed to assess medial patellofemoral ligament residual graft laxity. Among the 130 included cases, 104 knees with at least 1-year follow-up were included in the clinical outcome analyses to explore the influence of several anatomical factors and J-sign grade on short-term clinical outcomes.

RESULTS

A total of 118 patients (130 knees) were included in the present study. The median age at surgery was 21 years (range 13-38), and 111 affected knees belonged to female patients (85%). Univariate and multivariate logistic regressions between the grade 3 group and the grade 1-2 groups showed that increased femoral anteversion, excessive external tibial torsion, and patella alta were three independent risk factors of grade 3 J-sign in patients with recurrent patellar dislocation. A total of 104 knees with at least a 1-year follow-up were included in the clinical outcome analyses. The median Kujala score improved from 54 (range, 38-72) pre-operatively to 86 (range, 70-100) post-operatively. Although no re-dislocation was reported during the follow-up, 6 out of 32 patients in the grade 3 group demonstrated "MPFL residual graft laxity" based on post-operative stress radiography (18.8%), which was significantly higher than in the grade 1-2 groups (0%, p < 0.001). Subgroup analysis showed that patients with grade 3 J-sign had significantly lower post-operative Kujala scores than those with grade 1-2 J-sign (p < 0.001). Moreover, increased femoral anteversion (≥ 30°) was correlated with an inferior post-operative Kujala score (p = 0.023).

CONCLUSION

The three independent anatomic risk factors of grade 3 J-sign in patients with recurrent patellar dislocation were increased femoral anteversion, excessive external tibial torsion, and patella alta. A pre-operative grade 3 J-sign was correlated with a lower post-operative Kujala score and more "MPFL residual graft laxity" in patients with recurrent patellar dislocation treated with MPFL reconstruction with or without tibial tuberosity medialization at a minimum 1-year follow-up.

LEVEL OF EVIDENCE

III.

Failure Analysis in Patients With Patellar Redislocation After Primary Isolated Medial Patellofemoral Ligament Reconstruction

Background:

Reconstruction of the medial patellofemoral ligament (MPFL) has become a popular surgical procedure to address patellofemoral instability. As a consequence of the growing number of MPFL reconstructions performed, a higher rate of failures and revision procedures has been seen.

Purpose:

To perform a failure analysis in patients with patellar redislocation after primary isolated MPFL reconstruction.

Study Design:

Case series; Level of evidence, 4.

Methods:

Patients undergoing revision surgery for reinstability after primary isolated MPFL reconstruction were included. Clinical notes were reviewed to collect demographic data, information on the primary surgery, and the mechanism of patellar redislocation (traumatic vs nontraumatic). Preoperative imaging was analyzed regarding femoral tunnel position and the prevalence of anatomic risk factors (ARFs) associated with patellofemoral instability: trochlear dysplasia (types B through D), patella alta (Caton-Deschamps index >1.2, patellotrochlear index <0.28), lateralization of the tibial tuberosity (tibial tuberosity–trochlear groove distance >20 mm, tibial tuberosity–posterior cruciate ligament [TT-PCL] distance >24 mm), valgus malalignment (mechanical valgus axis >5°), and torsional deformity (internal femoral torsion >25°, external tibial torsion >35°). The prevalence of ARF was compared between patients with traumatic and nontraumatic redislocations and between patients with anatomic and nonanatomic femoral tunnel position.

Results:

A total of 26 patients (69% female) with a mean age of 25 ± 7 years were included. The cause of redislocation was traumatic in 31% and nontraumatic in 69%. Position of the femoral tunnel was considered nonanatomic in 50% of patients. Trochlear dysplasia was the most common ARF with a prevalence of 50%, followed by elevated TT-PCL distance (36%) and valgus malalignment (35%). The median number of ARFs per patient was 3 (range, 0-6), and 65% of patients had 2 or more ARFs. Patients with nontraumatic redislocations showed significantly more ARFs per patient, and the presence of 2 or more ARFs was significantly more common in this group. No significant difference was observed between patients with anatomic versus nonanatomic femoral tunnel position.

Conclusion:

Multiple anatomic risk factors and femoral tunnel malposition are commonly observed in patients with reinstability after primary MPFL reconstruction. Before revision surgery, a focused clinical examination and adequate imaging including radiographs, magnetic resonance imaging (MRI), standing full-leg radiographs, and torsional measurement with computed tomography or MRI are recommended to assess all relevant anatomic parameters to understand an individual patient’s risk profile. During revision surgery, care must be taken to ensure anatomic placement of the femoral tunnel through use of anatomic and/or radiographic landmarks.

[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.

Isolated trochleoplasty for recurrent patellar dislocation has lower outcome and higher residual instability compared with combined MPFL and trochleoplasty: a systematic review

PURPOSE

To identify the efficacy of isolated trochleoplasty (TP) as an independent treatment for severe trochlear dysplasia compared with TP combined with medial patellofemoral ligament (MPFL) reconstruction.

METHODS

Search of current literature using terms (trochleoplasty and medial patellofemoral ligament reconstruction) in the electronic search engines PubMed and Embase, and Medline databases was performed on February 25, 2018, and it yielded 515 abstracts for review. At the end of the search, six articles met specific inclusion criteria and were included in this review. Means were calculated for population size, age and follow-up time. The Kujala score was analyzed as the primary clinical outcome parameter in the meta-analysis. Pooled estimates were calculated for postoperative complications.

RESULTS

Six studies with a total of 192 knees (168 patients) were included in this analysis. The isolated TP group comprised of 3 articles with a total of 111 knees, and the TP combined with MPFL group comprised of 3 articles with a total of 81 knees. At the final follow-up, the preoperative Kujala score increased significantly by 21.39 (95% CI 18.94, 23.84; P < 0.00001) points in the isolated TP group and by 24.91 (95% CI 15.47, 34.36; P < 0.00001) points in the TP combined with MPFL group. The rates of subjective patellar instability including subluxation and anterior knee pain were 1.03% and8.45% respectively. Meanwhile, the rate of objective patellar redislocation was 2.06% in isolated TP group and 0% in TP combined with MFPL group. A total of 8.24% returned to the operating room for additional procedures in the isolated TP group and 7.04% in the TP combined with MPFL group.

CONCLUSION

Trochleoplasty is a useful and reliable surgical technique to improve patellofemoral instability in patients with a dysplastic trochlea. However, it as isolated treatment for patients has lower outcome and higher residual instability compared with combined MPFL and trochleoplasty.

Recurrent patellar dislocations: trochleoplasty improves the results of medial patellofemoral ligament surgery only in severe trochlear dysplasia

PURPOSE

Medial patellofemoral ligament (MPFL) surgery combined with trochleoplasty (TP), is often performed to restore the normal patellofemoral biomechanics avoiding recurrent lateral patellar dislocation (LPD) in patients with trochlear dysplasia (TD). However, it is still unclear whether combining TP and MPFL surgery would be more beneficial than performing MPFL surgery on its own. This meta-analysis quantitatively synthesizes and compares published data on the outcomes of recurrent LPD treatment using MPFL surgery without or with TP in patients affected by TD.

METHODS

A systematic literature search about the treatment of recurrent LPD in the presence of TD was conducted. The primary outcome was redislocation rate, analyzed for different types of TD. Kujala, and IKDC scores, as well as complication rate, were also analyzed through a separate meta-analysis.

RESULTS

No statistically significant difference was found in the overall redislocation rate of MPFL surgery without and with TP. There was, however, a statistically significant difference (p < 0.001) in redislocation rate after MPFL surgery without TP between patients with type A or B TD (2.7%) and in patients with type C or D TD (18.6%). In the analysis for every single type of TD, the following results were obtained: redislocation rate of 1.8% in type A, 3.2% in type B, 11.9% in type C, and 7.4% in type D. A statistically significant difference in the complication rate, favouring MPFL surgery without TP, was documented. Both surgical approaches provided a significant improvement with no difference in Kujala and IKDC scores. These results were confirmed when data were analyzed including only patients with type B, C, or D TD, or without additional bone remodelling procedures.

CONCLUSION

Isolated MPFL is as effective as combined TP and MPFL surgery in preventing redislocation and improving clinical and functional outcomes in patients with recurrent LPD and knees affected by moderate TD. However, in case of severe TD, the redislocation rate is lower when TP is performed in combination with MPFL surgery, although with comparable clinical outcomes and a higher risk of post-operative range of motion (ROM) limitation.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, Level IV.

Manipulation Under Anesthesia With Lysis of Adhesions Is Effective in Arthrofibrosis After Sulcus-Deepening Trochleoplasty: A Prospective Study

Background

Sulcus-deepening trochleoplasty has been established as an effective treatment for patellar instability due to trochlear dysplasia. However, arthrofibrosis is a known complication following trochleoplasty, which may require manipulation under anesthesia (MUA) with or without lysis of adhesions (LOA) to increase the knee range of motion (ROM), especially flexion.

Purpose

To prospectively follow patients for ROM improvements and subsequent complications after undergoing MUA with or without LOA in the setting of sulcus-deepening trochleoplasty.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 76 knees with severe trochlear dysplasia were prospectively enrolled and underwent sulcus-deepening trochleoplasty, with a mean (±SD) follow-up of 32.5 ± 19.3 months. Concomitant procedures included medial patellofemoral ligament reconstruction, lateral retinacular release, and tibial tubercle osteotomy. Physical examination including ROM and findings of recurrent patellar instability were collected for all patients. Arthrofibrosis was defined as active and passive flexion less than 90° within 3 months of surgery combined with a plateau in progress with physical therapy. Paired-samples and independent-samples t tests were used. A P value less than .05 was considered significant.

Results

A total of 62 knees met inclusion and exclusion criteria and were included in the study. Of these patients, 11 experienced arthrofibrosis as a complication and underwent MUA within 3 months of their index procedure. Of these 11 patients, 9 subsequently underwent arthroscopic LOA following MUA because acceptable ROM could not be achieved with manipulation alone. Patients with arthrofibrosis had a premanipulation mean ROM that was significantly different from those without arthrofibrosis (77.3° ±18.6° vs 133.3° ± 12.7°, respectively; P < .001). In the arthrofibrotic group, postoperative ROM increased significantly after MUA and/or LOA compared with the preoperative ROM (127.3° ± 12.5° vs 77.3° ± 18.6°, respectively; P < .001). ROM in the arthrofibrotic group after MUA/LOA was not significantly different from that in the nonarthrofibrotic group (flexion, 127.3° ± 12.5° vs 133.3° ± 12.7°, respectively; P = .156). No complications from the MUA or LOA were reported at subsequent follow-up visits.

Conclusion

When indicated in the setting of severe trochlear dysplasia, sulcus-deepening trochleoplasty is a treatment for disabling recurrent patellar instability with a known complication of arthrofibrosis. Initiation of postoperative physical therapy within 3 days of surgery may reduce the incidence of arthrofibrosis. If arthrofibrosis is encountered after a sulcus-deepening trochleoplasty, MUA without LOA is not as effective as when following other procedures of the knee, whereas MUA with LOA is an effective procedure likely to result in ROM and patient outcome scores similar to those of a nonarthrofibrotic knee after the same procedure. Both MUA and LOA appear to be safe based on the limited number of patients in this study without complication.

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.

Patient-Reported Outcome Measures for Patellofemoral Instability: a Critical Review

PURPOSE OF REVIEW

The purpose of this paper was to review the current psychometric properties of patient-reported outcome measures that are commonly used for patients with patellofemoral instability. This review provides evidence to guide the selection of subjective outcome measures for assessing outcomes in clinical care and research studies.

RECENT FINDINGS

At the present time, there are two patient-reported outcome measures that have been designed for, and tested on, large cohorts of patellofemoral instability patients, the Banff Patella Instability Instrument (BPII) and the Norwich Patellar Instability Score (NPI). The BPII is a wholistic quality of life outcome measure and the NPI is a symptom score. The use of disease-specific outcome measures such as the BPII and NPI, in combination with generic knee, functional activity, and/or psychological outcome measures that have been proven to be valid and reliable for the patellofemoral instability population, is most likely to provide a well-rounded evaluation of treatment outcomes.

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 techniques provide good clinical results in patients with trochlear dysplasia

PURPOSE

The aim of this systematic review is to compare the clinical outcomes of patients treated with different trochleoplasty procedures, the rate of complications and recurrence of patellar dislocation.

METHODS

A systematic review of the literature was performed, in accord with the PRISMA guidelines. PubMed, MEDLINE, CINAHL, Cochrane, EMBASE and Google Scholar databases were comprehensively searched using the keyword combinations, "Dejour trochleoplasty", "Bereiter Trochleoplasty", "Albee Trochleoplasty", "Recession Trochleoplasty", "Trochlear Dysplasia", "Instability", "Adult", "Clinical Outcome" and "Surgery".

RESULTS

Three-hundred and ninety-two knees in 371 patients were included. Bereiter U-shaped deepening trochleoplasty was the most commonly used technique for the treatment of trochlear dysplasia in the included studies with the lowest rate of recurrence and post-operative ROM deficiency. On the other hand, Dejour V-shaped deepening trochleoplasty showed the highest mean post-operative value of Kujala score with 79.3 (SD 8.4) points. Statistical differences were found in terms of redislocation rate between Goutallier procedure and Bereiter trochleoplasty (p < 0.05) and in terms of post-operative osteoarthritis between Bereiter and Dejour procedures (p < 0.05).

CONCLUSION

Bereiter trochleoplasty seems to be the most efficiency procedure in terms of post-operative patellar redislocation, post-operative osteoarthritis and ROM, but the highest mean post-operative Kujala score is obtained by Dejour procedure. Therefore, none of the surgical techniques analysed highlighted a real superiority. Randomised clinical trials are needed to establish whether of available surgical technique is the best to treat patient with trochlear dysplasia. The clinical relevance of this paper is that the three most popular trochleoplasty techniques are associated with significantly improved stability and function, showing a relatively low rate of osteoarthritis and pain, and a moderate rate of complications.

LEVEL OF EVIDENCE

Systematic review, Level IV.

Return-to-Play Guidelines After Medial Patellofemoral Ligament Surgery for Recurrent Patellar Instability: A Systematic Review

BACKGROUND

Medial patellofemoral ligament (MPFL) reconstruction and repair continue to gain acceptance as viable treatment options for recurrent patellar instability in patients who wish to return to sports after surgery. Return-to-play guidelines with objective or subjective criteria for athletes after MPFL surgery, however, have not been uniformly defined.

PURPOSE

To determine whether a concise and objective protocol exists that may help athletes return to their sport more safely after MPFL surgery.

STUDY DESIGN

Systematic review.

METHODS

The clinical evidence for return to play after MPFL reconstruction was evaluated through a systematic review of the literature. Studies that measured outcomes for isolated MPFL surgery with greater than a 12-month follow-up were included in our study. We analyzed each study for a return-to-play timeline, rehabilitation protocol, and any measurements used to determine a safe return to play after surgery.

RESULTS

Fifty-three studies met the inclusion criteria, with a total of 1756 patients and 1838 knees. The most commonly cited rehabilitation guidelines included weightbearing restrictions and range of motion restrictions in 90.6% and 84.9% of studies, respectively. Thirty-five of 53 studies (66.0%) included an expected timeline for either return to play or return to full activity. Ten of 53 studies (18.9%) in our analysis included either objective or subjective criteria to determine return to activity within their rehabilitation protocol.

CONCLUSION

Most studies in our analysis utilized time-based criteria for determining return to play after MPFL surgery, while only a minority utilized objective or subjective patient-centric criteria. Further investigation is needed to determine safe and effective guidelines for return to play after MPFL reconstruction and repair.

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.

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.

Validation of the German version of the Kujala score in patients with patellofemoral instability: a prospective multi-centre study

INTRODUCTION

The Kujala score is the most frequently used questionnaire for patellofemoral disorders like pain, instability or osteoarthritis. Unfortunately, we are not aware of a validated German version of the Kujala score. The aim of our study was the translation and linguistic validation of the Kujala score in German-speaking patients with patella instability and the assessment of its measurement characteristics.

MATERIALS AND METHODS

The German Kujala score was developed in several steps of translation. In addition to healthy controls, the Kujala German was assessed in consecutive patients undergoing reconstruction of the medial patellofemoral ligament for recurrent patellar dislocations. Pre-op, 6 and 12 months postop the patients completed the Kujala German score, the KOOS, the Lysholm score, a VAS Pain, and the SF-12v2 scores. In addition, there was a Kujala German Score retest preop after a 1-week interval.

RESULTS

We found high reliability in terms of internal consistency for the Kujala score (Cronbach's alpha = 0.87). Convergent validity with the KOOS (symptom r = 0.65, pain r = 0.78, ADL r = 0.74, sports/recreation r = 0.84, quality of life r = 0.70), the Lysholm score (r = 0.88) and the SF-12 physical component summary score (r = 0.79) and VAS pain (r = - 0.71) was also very high. Discriminant validity in terms of correlation with the SF-12 mental component summary Score was satisfactory (r = 0.14).

CONCLUSIONS

In conclusion, the German version of the Kujala score proved to be a reliable and valid instrument in the setting of a typical patellofemoral disease treated with a standard patellofemoral procedure.

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.

Results of medial patellofemoral ligament reconstruction compared with trochleoplasty plus individual extensor apparatus balancing in patellar instability caused by severe trochlear dysplasia: a systematic review and meta-analysis

PURPOSE

Many studies have reported satisfactory clinical outcomes and low redislocation rates after reconstruction of the medial patellofemoral ligament (MPFL) for the treatment of lateral patellar instability. Despite uncorrected severe trochlear dysplasia (Dejour type B to D) being acknowledged as a major reason for less favourable clinical outcomes and a higher incidence of patellar redislocations after an isolated MPFL reconstruction, the evidence for a deepening trochleoplasty procedure remains scarce in the current literature. The hypothesis of this systematic review and meta-analysis was that a deepening trochleoplasty in combination with an a la carte extensor apparatus balancing procedure provides lower redislocation rates and superior clinical outcomes than isolated MPFL reconstruction in patients with lateral patellar instability caused by severe trochlear dysplasia.

METHODS

A systematic review of the literature was conducted using specific inclusion and exclusion criteria for clinical studies reporting index operations (trochleoplasty and MPFL reconstruction) for the treatment of patellar instability caused by severe trochlear dysplasia. The Kujala score was analysed as the primary clinical outcome parameter in a random effects meta-analysis.

RESULTS

Ten uncontrolled studies with a total of 407 knees (374 patients) were included in this analysis. The MPFL group comprised 4 studies with a total of 221 knees (210 patients), and the trochleoplasty group comprised 6 studies with a total of 186 knees (164 patients). The mean preoperative Kujala score ranged between 50.4 and 70.5 in the MPFL group and between 44.8 and 75.1 in the trochleoplasty group. The pooled Kujala score increased significantly by 26.4 (95% CI 21.4, 31.3; P < 0.00001) points in the MPFL group and by 26.2 (95% CI 19.8, 32.7; P < 0.00001) points in the trochleoplasty group. The post-operative patellar redislocation/subluxation rate was 7% in the MPFL group and 2.1% in the trochleoplasty group.

CONCLUSION

This analysis found significant post-operative improvements in patient-reported outcomes for patients undergoing both an MPFL reconstruction and in those undergoing a trochleoplasty plus an individual extensor apparatus balancing procedure when assessed using the Kujala score. The likelihood of preventing the patella from subsequent post-operative redislocation/subluxation was, however, greater in patients who underwent trochleoplasty plus extensor balancing.

LEVEL OF EVIDENCE

IV.

Arthroscopic deepening trochleoplasty for chronic anterior knee pain after previous failed conservative and arthroscopic treatment. Report of two cases

•

This study acknowledge that chronic anterior knee pain or patellofemoral can be caused based on trochlear dysplasia.

•

The paper discuss the scientific background for this.

•

By restoring the patient anatomy performing an arthroscopic trochleoplasty, the patients anterior knee pain was reduced significantly.

Purpose

A proportion of patients having years of chronic anterior knee pain(AKP) that have not responded to non-operative modalities. Trochlear dysplasia have been found to be a cause for AKP. By restoring the anatomy with a trochleoplasty procedure the patellofemoral joint is unloaded. This study is a prospective 2 year follow-up study, based on two cases with chronic AKP for several years and having severe trochlear dysplasia and both were successfully treated by arthroscopic deepening trochleoplasty.

Methods

Case one was a 46 year old women with chronic anterior knee pain (AKP). Imaging showed lateral trochlear inclination angle of 2°, trochlear asymmetry 0.36, central height 81% and medial height 83%. Thepreoperative Kujala score was 70 and Knee injury and Osteoarthritis Outcome Score (KOOS) subscale for pain was 67. Case two was a 26 year old man troubled by AKP and knee knee joint effusion for >8 years without any instability in the history. Imaging showed lateral trochlear inclination angle of 6°, trochlear asymmetry 0.25, central height 76% and medial height 78%. The preoperative Kujala score was 49 and KOOS subscale for pain was 72.

Results

The postoperative Kujala score was for case one 82 and for case two 81. The postoperative KOOS subscale for pain was for case one 89 and for case two 92. Improvement in the KOOS subscale for sport and recreational activities and quality of living were also found.

Conclusion

This is the first case report to demonstrate that patient having had years of chronic AKP and trochlear dysplasia can be successfully treated by arthroscopic trochleoplasty.

The lateral wedge augmentation trochleoplasty in a pediatric population: a 5-year follow-up study

Patellofemoral instability in children requires surgery when recurrent dislocation occurs. The aim of this study is to report the 5-year clinical and radiographic outcomes following lateral wedge augmentation trochleoplasty of the femoral trochlea. This is a review of 23 (mean age: 12.5 years) patients who underwent surgery for recurrent patellar dislocations related to a flat trochlea. In every case, a lateral wedge augmentation trochleoplasty was performed with preservation of the growth plate. This surgery was consistently associated with a soft tissue procedure. All patients were reviewed for a clinical and radiographic evaluation [computed tomography (CT)-scan]. No case of recurrent patellar dislocation was reported and all patients were satisfied with the procedure; three patients reported anterior knee pain after physical activities. CT scan analysis revealed improvement of the trochlear shape measurements in all cases, but osteoarthritis lesions (narrowing of the lateral patellofemoral compartment) were visible on four CT scans. This trochleoplasty technique augmented by a soft tissue procedure on the extensor apparatus led to acceptable clinical mid-term results in terms of stability for patients with a flat trochlea (grade B according to Dejour classification). However, at the 5-year follow-up, four patients showed signs of osteoarthritis on CT scan evaluation. This warrants serious concern in this young population, and alternative methods should be considered whenever possible.

Medial Patellofemoral Ligament Reconstruction Combined With Bony Procedures for Patellar Instability: Current Indications, Outcomes, and Complications

PURPOSE

The aim of this literature review is to analyze current indications, outcomes, and complication rates of medial patellofemoral ligament (MPFL) reconstruction associated with bony procedures in order to clarify efficacy and adoptability in selected patients with patellar instability.

METHODS

A systematic review of the literature was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search on PubMed, Medline, CINAHL, Cochrane, Embase, and Google Scholar databases was performed, using various combinations of the keywords patellar instability, MPFL reconstruction, tibial tubercle osteotomy, and trochleoplasty.

RESULTS

Fourteen of 501 articles were included. Indications for surgery included dysplasia and malalignment. All studies reported significant improvements in overall clinical outcomes. The most frequently used score was the Kujala score, with a mean value of 83.26. Functional failures ranged from 0% to 8.8%. Major complications were not described. Minor complications ranged from 0% to 40%. Reoperations ranged from 4.5% to 17.7%.

CONCLUSIONS

A combined approach seems indicated in patients with patellar instability, especially among those with high tibial tuberosity-trochlear groove or severe trochlea dysplasia. Indications for combined MPFL and bony procedure are influenced by anatomy, including dysplasia and malalignment. We are unable to identify an absolute indication. Bony procedures are associated with increased morbidity.

LEVEL OF EVIDENCE

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

A new classification system of patellar instability and patellar maltracking

To date there is no classification of patellar dislocations considering clinical and radiological pathologies. As a result many studies mingle the dislocation's underlying pathologies, so that there are no consistent therapy recommendations. It is this article's objective to introduce a patellar dislocation classification based on the current literature to allow for the application of a structured diagnosis and treatment algorithm. The classification is based on instability criteria as well as on clinical and radiological analyses of maltracking and on loss of patellar tracking. There are five types of patellar instability and maltracking. The rare type 1 is a simple (traumatic) patellar dislocation without maltracking and instability with a low risk of redislocation. Type 2 has a high risk of redislocation after primary dislocation; there is no maltracking. Here, a stabilising operation (in most cases MPFL reconstruction) is indicated and sufficient. Type 3 shows both instability and maltracking. Maltracking is mainly caused by: (a) soft tissue contracture, (b) patella alta, (c) pathological tibial tuberosity-trochlea groove distance, (d) valgus deviations and (e) torsional deformities. Stabilisation by means of isolated MPFL reconstruction is not sufficient in these types and additional osseous corrective surgeries are required to achieve physiological patellar tracking and to prevent redislocation. Type 4 features a highly unstable "floating patella" with complete loss of tracking caused by severe trochlear dysplasia. Therapy of choice is trochleoplasty, and if necessary combined with bony and soft-tissue procedures. Type 5 shows a patellar maltracking without instability. Maltracking can only be fixed by means of corrective osteotomy. The classification is referenced to current literature and each type is introduced by a case example. The resulting treatment consequence is also presented.

Osteochondral Allograft Transplantation for Femoral Trochlear Dysplasia

BACKGROUND

The risk factors for patellofemoral joint instability include laxity of medial patellar restraints, abnormal limb geometry, femoral and tibial malrotation, patella alta, and trochlear dysplasia. Femoral trochlear dysplasia is characterized by a hypoplastic or shallow trochlear groove.

CASE REPORT

We report the case of a 31-year-old female with trochlear dysplasia and recurrent patella dislocations, laxity of the medial patellofemoral ligament (MPFL), and high-grade chondromalacia of the trochlea and the patella. Surgical treatment goals were to re-create a trochlear groove, restore bony restraint, and realign and offload the patella. First, a triplane tibial tubercle osteotomy (TTO) was performed, and the patella was everted 360° with a subvastus approach. The MPFL was reconstructed using a gracilis allograft. A fresh osteochondral allograft transplant trochlea was sized, and a 35-mm diameter graft was transplanted to re-create the groove. The TTO was secured in a new anterior, medial, and distal position. The patient was braced for 6 weeks and completed a rehabilitation protocol. At 9-month follow-up, she had made significant gains in range of motion (0°-140°) and activity compared to her preoperative status. She reported no pain or recurrent dislocations.

CONCLUSION

This case demonstrates a viable surgical option for treatment of instability resulting from trochlear dysplasia with patellofemoral chondromalacia. The osteochondral allograft transplantation surgery technique allows patients to have a stable, pain-free knee joint and participate in activities compared to nonoperative management. However, the long-term outcomes of this procedure are unknown.

Clinical outcome after reconstruction of the medial patellofemoral ligament in patients with recurrent patella instability

PURPOSE

We present the clinical results of a large consecutive, prospective, single-clinic series of patients treated with medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability.

METHODS

The study included 224 patients undergoing MPFL reconstruction in a total of 240 knees between 2008 and 2011. Indication for surgery was two or more patellar dislocations and ADL limitations due to patella instability.

SURGICAL PROCEDURE

A gracilis tendon autograft was fixed in drill holes in the medial edge of the patella and with screws at the femoral MPFL insertion point. Outcomes were evaluated with the Kujala Anterior Knee Pain Score and pain scores preoperatively and at follow-up (12-60 months). Furthermore, incidences of re-dislocations, subluxations and revision surgery were evaluated.

RESULTS

The Kujala score improved from 62.5 (17) to 80.4 (18) (p<0.001) at the 1-year follow-up. Pain during activity improved from 3.2 (2.6) to 1.3 (2.7) at 1 year (p<0.001). The revision rate was 2.8%. Some degree of pain at the medial femoral condyle was seen in 30% of the patients. The reconstruction was supplemented with a tibial tuberosity osteotomy in 23% of cases. The outcome for these patients did not differ from that of patients with isolated MPFL reconstruction. Female gender BMI>30, age>30 years and grade 3-4 cartilage injury predisposed a poor subjective outcome.

CONCLUSIONS

The present study is the largest MPFL reconstruction patient material reported to date. MPFL reconstruction with a gracilis tendon autograft consistently normalised the patella stability and improved knee function. Moderate medial pain was seen. Age above 30, obesity, cartilage injury and female gender are predictors of a poor subjective outcome.

LEVEL OF EVIDENCE

Level IV.

Current concepts on trochleoplasty procedures for the surgical treatment of trochlear dysplasia

Trochleoplasty is a surgical procedure, whose goal is to change the abnormal shape of the femoral trochlea in patients with recurrent patellar dislocation. Such surgeries that aim to reshape the articular surface of a bone without damaging it are quite unique in orthopaedic surgery. Although in the beginning, trochleoplasty was reserved for the refractory cases where previous surgery has failed, the last years it became more and more popular because of a better knowledge of anatomy and biomechanics and a greater availability of instruments. The roots of the deepening trochleoplasty could be found in the previous century when the first surgeons tried to directly remove the dysplastic bone with pioneer interventions but with devastating consequences. Since then, multiple procedures have been described and are analysed in this review; each one with its unique features, advantages and pitfalls. Regardless of the technique used, the very recent bibliography presents very encouraging results from the application of trochleoplasty with other procedures in a selected population with severe trochlear dysplasia and recurrent patellar dislocation, in whom the benign neglect of dysplasia would lead to unfavourable results.

LEVEL OF EVIDENCE

IV.