The sulcus deepening trochleoplasty—the Lyon’s procedure

Sulcus deepening trochleoplasty is a technically demanding procedure with precise indications: high grade trochlear dysplasia with patellar instability and/or abnormal tracking. The main goal is to decrease the prominence of the trochlea and to create a new groove with normal depth, thus optimising patellar tracking. Associated abnormalities should be specifically treated. Recurrence of instability is very rare after this procedure and is more likely to result from missed associated abnormalities. Although results seem very good in terms of instability, further evidence is still needed since the groups of patients in the published series are heterogeneous. Trochleoplasty is not indicated for patellofemoral arthritis or pain. As any surgical procedure, sulcus deepening trochleoplasty is liable to complications.     

The effect of trochleoplasty on patellar stability and kinematics: a biomechanical study in vitro

Objective patellar instability has been correlated with dysplasia of the femoral trochlea. This in vitro study tested the hypothesis that trochleoplasty would increase patellar stability and normalise the kinematics of a knee with a dysplastic trochlea. Six fresh-frozen knees were loaded via the heads of the quadriceps. The patella was displaced 10 mm laterally and the displacing force was measured from 0 degrees to 90 degrees of flexion. Patellar tracking was measured from 0 degrees to 130 degrees of knee flexion using magnetic sensors. These tests were repeated after raising the central anterior trochlea to simulate dysplasia, and repeated again after performing a trochleoplasty on each specimen. The simulated dysplasia significantly reduced stability from that of the normal knee (p < 0.001). Trochleoplasty significantly increased the stability (p < 0.001), so that it did not then differ significantly from the normal knee (p = 0.244). There were small but statistically significant changes in patellar tracking (p< 0.001). This study has provided objective biomechanical data to support the use of trochleoplasty in the treatment of patellar instability associated with femoral trochlear dysplasia.     

Trochleoplasty and medial patellofemoral ligament reconstruction for recurrent patellar dislocation

We report a case of recurrent patellar dislocation with high-grade trochlear dysplasia which persisted despite two previous operations. We did a Dejour''s sulcus deepening trochleoplasty, medial patellofemoral ligament reconstruction, and lateral retinacular release. Trochleoplasty and medial patellofemoral ligament reconstruction is required in patients with high grade trochlear dysplasia.     

Editorial Commentary: Trochleoplasty: Is It Really That Fearsome and Dangerous a Technique?

Trochleoplasty in patellofemoral instability has always been controversial. Most authors recognize the fundamental role of trochlear dysplasia in the genesis of patellar dislocation, and some strongly defend correcting the abnormality, yet others find it too dangerous or unnecessary. Misunderstanding or undervaluation of trochlear dysplasia leads to inappropriate or failed patellofemoral (PF) surgery, the iatrogenic complications of which are well known. Many surgeons miss a key aspect of trochlear dysplasia: the overhang or the prominence of the trochlea relative to the anterior femoral cortex, characterized by a supra-trochlear spur. Trochleoplasty should not be performed as a secondary or revision procedure, but as a primary procedure with clear indications, and the key to improved outcomes is to ensure the right indication for each patient, which can only be determined by understanding the extent of dysplasia in both the axial and sagittal planes.     

The Lyon’s sulcus-deepening trochleoplasty in previous unsuccessful patellofemoral surgery

Purpose

Trochleoplasty is a relatively rare operation with few published results and it remains a technically demanding procedure which requires careful patient selection. The ideal candidate for surgery remains to be elucidated, and some authors consider it as a good revision option in cases of previous unsuccessful operations for persisting patellar dislocation with underlying trochlear dysplasia. The purpose of this study is to record the results from the application of sulcus-deepening trochleoplasty in patients with trochlear dysplasia and previous unsuccessful surgery for patellar dislocation.

Methods

Twenty-two patients (24 knees) were operated upon during the period 9/1993–9/2006; they had undergone surgery for patellofemoral instability and had persistent patellar dislocation, and were followed-up for a mean of 66 months (24–191). Trochleoplasty was performed in all patients using the same technique and rehabilitation protocol. Additional soft-tissue and bony operations were performed in every case.

Results

Of all cases, 29.1 % had type B and 70.9 % had type D trochlear dysplasia. After trochleoplasty, no patient had a patellar re-dislocation up to the last follow-up. Pain decreased in 72 % and the apprehension sign was negative in 75 % of the cases (p < 0.01). Sulcus angle decreased from 153° ± 14° to 141° ± 10° (p < 0.01), TT-TG distance decreased from 16 ± 6 mm to 12 ± 2 mm (p < 0.001), and patellar tilt decreased from 31° ± 14° to 11° ± 8° (p < 0.0001). Mean pre-operative Kujala score was 44 (25–73) and at the latest follow-up it increased to 81 (53–100), (p < 0.001). At the time of final follow-up, there was no case of patellofemoral arthritis.

Conclusions

Trochlear dysplasia is a key factor in the treatment of recurrent patellar dislocation and its correction could be included in the surgical options. Sulcus-deepening trochleoplasty is an acceptable revision option for the surgical treatment of patients with persisting patellar dislocation and high-grade trochlear dysplasia.     

Editorial Commentary: Trochlear Dysplasia: Can We Change its Natural History or Degenerative Prognosis?

Trochlear dysplasia may be asymptomatic and benign, or could engender patellar instability and degenerative arthritis. Autologous chondrocyte implantation is demonstrating promising outcomes for the treatment of patellofemoral cartilage lesions, but may not suffice for knees with underlying mechanical anomalies as trochlear dysplasia, where adjuvant trochleoplasty or tibial tubercle osteotomy may be required to prevent patellofemoral instability and to protect the graft from wear and damage. Rigorous radiographic assessment is important to discern the type of dysplasia, notably the presence of a potentially pathogenic supra-trochlear spur. Trochleoplasty or other realignment procedures such as tibial tubercle osteotomy should be considered where necessary to correct underlying trochlear deformities and thereby avoid iatrogenic complications or failure.     

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.     

Trochleaplasty for patellar instability due to trochlear dysplasia: A minimum 2-year clinical and radiological follow-up of 19 knees

Background Recurrent patellar dislocation may be associated with trochlear dysplasia. Trochleaplasty is a surgical procedure which strives to deepen the trochlear groove. We evaluated the clinical and radiological effect of trochleaplasty after a minimum follow-up of 2 years.

Patients and methods We examined 19 knees in 16 patients at a mean of 3 years after trochleaplasty. Postoperatively, a subjective questionnaire, a Kujala score, and tests for potential patellar redislocation and apprehension were evaluated. On radiographs we evaluated the preoperative and postoperative crossing sign, trochlear depth, trochlear bump, and patellar height. On CT scans, the pre- and postoperative tibial tuberosity to trochlear groove distance (TTTG) and the patellar inclination angle were measured.

Results 16 of 19 knees improved subjectively. The Kujala score increased from 56 to 80 points at the latest follow-up. None of the patients sustained a redislocation. 5 patients had medial parapatellar tenderness, including 4 with persistent apprehension. Radiological signs of trochlear dysplasia were corrected.

Interpretation Patellofemoral instability with underlying trochlear dysplasia can be treated successfully by trochleaplasty.     

Trochleaplasty for patellar instability due to trochlear dysplasia

Background?Recurrent patellar dislocation may be associated with trochlear dysplasia. Trochleaplasty is a surgical procedure which strives to deepen the trochlear groove. We evaluated the clinical and radiological effect of trochleaplasty after a minimum follow-up of 2 years.

Patients and methods?We examined 19 knees in 16 patients at a mean of 3 years after trochleaplasty. Postoperatively, a subjective questionnaire, a Kujala score, and tests for potential patellar redislocation and apprehension were evaluated. On radiographs we evaluated the preoperative and postoperative crossing sign, trochlear depth, trochlear bump, and patellar height. On CT scans, the pre- and postoperative tibial tuberosity to trochlear groove distance (TTTG) and the patellar inclination angle were measured.

Results?16 of 19 knees improved subjectively. The Kujala score increased from 56 to 80 points at the latest follow-up. None of the patients sustained a redislocation. 5 patients had medial parapatellar tenderness, including 4 with persistent apprehension. Radiological signs of trochlear dysplasia were corrected.

Interpretation?Patellofemoral instability with underlying trochlear dysplasia can be treated successfully by trochleaplasty.     

Editorial Commentary: Which Came First,the Patella or the Trochlea? Morphological Relationships in Patients With Patellar Instability

Trochlear dysplasia and patella alta are known risk factors for patellar instability, yet the relation between the two has not been well understood. Morphologic abnormalities such as trochlear dysplasia and patella alta are known to alter patellofemoral kinematics, whereas altered contact pressures, in turn, have been associated with the development of trochlear dysplasia. As our current treatments aim to correct these deformities through increasingly complex procedures such as trochleoplasty and tuberosity distalization, we should consider this relation and the potential for changing the course of developing such morphologic abnormalities earlier in life. Further studies on the developmental cause of this disorder may help guide future treatments in the management of patellar instability.     

Radiological criteria for trochlear dysplasia in children and adolescents

Trochlear dysplasia is a well-known cause for recurrent patellar instability. Besides clinical findings, the treatment is based on radiological diagnostic tools. In adults the characteristics of trochlear dysplasia are determined by magnetic resonance imaging (MRI) scans as well as on true lateral radiographs. For children there are no established criteria for the radiological diagnosis of trochlear dysplasia. This study was designed to evaluate if typical radiological findings of trochlear dysplasia on lateral radiographs in adults are also found in children and adolescents with open growth plates. We analyzed true lateral radiographs of children and adolescents with MRI-detected trochlear dysplasia. On lateral radiographs three factors were relevant: crossing sign (deepest part of the trochlea crosses the most anterior point of the lateral condyle), a supratrochlear spur or bump (bulge of the proximal trochlea), and a double contour (due to a hypoplastic medial condyle). In all patients with trochlear dysplasia at least one typical radiological finding usually found in adults could be documented. Only true lateral radiographs allow the diagnosis of trochlear dysplasia in children and adolescents with open physis to be made. MRI scans on a regular basis are, therefore, not mandatory although they are the diagnostic golden standard for the diagnosis of trochlear dysplasia.     

Familial association of femoral trochlear dysplasia with recurrent bilateral patellar dislocation

Femoral trochlear dysplasia is an anatomic deformity that predisposes patients to patellar instability, including patellar subluxation and dislocation, and can lead to severe patellofemoral joint degeneration if left untreated. Femoral trochlear dysplasia leading to recurrent bilateral patellar dislocation has rarely been reported as having a familial association. Orthopedic surgeons who encounter patients presenting with chronic patellar instability with no underlying disease or syndrome should be aware of the presence of femoral trochlear dysplasia leading to recurrent bilateral patellar dislocation. Although femoral trochlear dysplasia remains uncommon, the presence of bilateral recurrent patellar dislocation in multiple members of the same family is highly suggestive of genetic inheritance.This article describes 3 patients from 1 family who presented with femoral trochlear dysplasia leading to recurrent bilateral patellar dislocation. To our knowledge, this is the second article to describe a familial form of femoral trochlear dysplasia associated with recurrent bilateral patellar dislocation and is the first article in English. A lower threshold for screening and early intervention for symptomatic family members may be indicated to prevent the long-term effects of chronic patellar subluxation, dislocation, and patellofemoral arthritis.     

The lateral condyle index: a new index for assessing the length of the lateral articular trochlea as predisposing factor for patellar instability

The central trochlea has been considered as the major location of dysplasia. The purpose of this study was to investigate the influence of the lateral trochlea on patellar stability and to establish a new method for measuring the lateral trochlea on sagittal magnetic resonance (MR) images. Twenty-eight knees of 23 patients suffering from lateral patellar subluxation (12 knees with radiological signs of central trochlear dysplasia) and of 46 patients without patellofemoral complaints (without central trochlear dysplasia) were analysed. The lateral condyle index was designed to measure the lateral trochlea by comparing the anterior cartilaginous trochlea (a) and the posterior aspect (p) [(a:p)× 100]. The lateral condyle index showed high interrater reliability (r = .94) and was significantly (p < 0.001) lower in symptomatic patients (86%) than in the control group (93%). These results show high clinical relevance of the lateral trochlea as another factor for patellar instability.     

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

PurposeA 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.MethodsCase 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.ResultsThe 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.ConclusionThis 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.     

Patellar osteotomy and Albee's procedure for dysplastic patellar instability

Four patients with symptomatic patellar instability and dysplasia of the patella and femoral trochlea had a dorsal closed-wedge intraarticular sagital plane patellar osteotomy and elevation of lateral femoral condyle-Albee's procedure. All patients also had a "Modified Fulkerson-Elmslie Trillat" osteotomy of the tibial tuberosity, along with a proximal realignment-lateral release and medial plication either prior to or at the time of index surgery of patellar osteotomy and Albee's procedure. At a mean follow-up of 1 (range 3 1/2–1) year, all patients had a stable patellofemoral joint. Mean loss of range of terminal flexion was 15° (range10–20°). All patients had residual patellofemoral pain, and the results at best can be described as fair. The results of this series are encouraging in this complex group of patients with patellofemoral trochlear dysplasia with patellar instability, and we do recommend this procedure as a palliative procedure in this group of patients.     

Editorial Commentary: What Is the Optimal Management of First and Recurrent Patellar Instability? Patellofemoral Instability Management Continues to Evolve

Patellar instability patients may present for evaluation after their first instability episode or after recurrent episodes. Current management differs for these 2 groups. The accepted “common denominator” of patellar instability is the medial patellofemoral ligament, or medial patellar restraints, to be more all-encompassing. These patients often have multiple contributing comorbidities (e.g., trochlear dysplasia, patellar alta, excessive lateral position of tibial tubercle). Historically, the recommended treatment for a first-time patellar dislocation was nonoperative because medial soft tissue repairs had not been proven more effective. Indications for primary repair of the medial patellar restraints are a single discrete tear identified on magnetic resonance imaging. In the case of recurrent patellar instability, medial patellofemoral ligament reconstruction, rather than repair/reef, has been the recommended approach. The keys to reconstruction remain: honor the anatomy and avoid overconstraint of the patella. For first time dislocation patients with trochlear dysplasia, patellar alta, and age <25 years, recurrent instability is common.     

A prospective evaluation of trochleoplasty for the treatment of patellofemoral dislocation and instability

Trochlear dysplasia is a developmental condition characterised by an abnormally flat or dome-shaped trochlea and is an important contributory factor to patellofemoral instability and recurrent dislocation. We studied prospectively a series of 54 consecutive patients (59 knees) with patellofemoral instability secondary to trochlear dysplasia, who were treated by a trochleoplasty by a single surgeon between June 2002 and June 2007. Pre- and post-operative scores were assessed by the patients and a satisfaction questionnaire was completed. Of the 54 patients (59 knees) in the series, 39 (44 knees) were female and 15 (15 knees) were male. Their mean age at surgery was 21 years and 6 months (14 years 4 months to 33 years 11 months). In 40 patients (42 knees) the mean follow-up was for 24 months (12 to 58). One patient was unable to attend for follow-up. An analysis of the results of those patients followed up for at least 12 months showed a statistically significant improvement in outcome (p < 0.001 for all scores). Overall, 50 patients (92.6%) were satisfied with the outcome of their procedure. The early results of trochleoplasty are encouraging in this challenging group of patients.     

Trochleaplasty for recurrent patellar dislocation in association with trochlear dysplasia. A 4- to 14-year follow-up study

We investigated the clinical and radiological outcome of trochleaplasty for recurrent patellar dislocation in association with trochlear dysplasia in 38 consecutive patients (45 knees) with a mean follow-up of 8.3 years (4 to 14). None had recurrence of dislocation after trochleaplasty. Post-operatively, patellofemoral pain, present pre-operatively in only 35 knees, became worse in 15 (33.4%), remained unchanged in four (8.8%) and improved in 22 (49%). Four knees which had no pain pre-operatively (8.8%) continued to have no pain. A total of 33 knees were available for radiological assessment. Post-operatively, all but two knees (93.9%) had correction of trochlear dysplasia radiologically but degenerative changes of the patellofemoral joint developed in 30% (10) of the knees. We conclude that recurrent patellar dislocation associated with trochlear dysplasia can be treated successfully by trochleaplasty, but the impact on patellofemoral pain and the development of patellofemoral osteoarthritis is less predictable. Overall, subjective patient satisfaction with restored patellofemoral stability after trochleaplasty appeared to outweigh its possible sequelae.     

Is femoral trochlear dysplasia related to global joint hypermobility?

BackgroundHypermobility is a known risk factor for patellar instability. In this study, we hypothesized that a significant relationship exists between global joint hypermobility and trochlear dysplasia.MethodsFollow-up patients from the shoulder department of our institution with global joint hypermobility (Group 1, n = 42) and healthy volunteers (Group 2, n = 42) without known knee complaints were included in our study. All participants underwent knee magnetic resonance imaging (MRI) for the evaluation of possible trochlear dysplasia, and the measurements included lateral trochlear inclination; trochlear facet asymmetry; the depth of the trochlear groove; condylar asymmetry; lateralization of the patella; sulcus angle; and the lateral, medial and central trochlear height. The Dejour classification was also assessed.ResultsThe age and gender distributions of the groups were similar (p > 0.05). The radiological evaluations revealed that the lateral trochlear inclination (p < 0.001), trochlear facet asymmetry (p < 0.001), depth of the trochlear groove (p < 0.001), lateralization of the patella (p < 0.001), sulcus angle (p < 0.001), and central trochlear height (p < 0.001) were significantly different between the two groups. The condylar asymmetry and lateral and femoral condylar height parameters were similar between the groups (p = 0.297, p = 0.890 and p = 0.521, respectively). According to the Dejour classification, 39 patients had dysplasia in Group 1, whereas dysplasia was detected in only 4 of the participants in Group 2.ConclusionsOur study revealed that most of the trochlear dysplasia criteria were met in patients with global joint hypermobility. In addition to a clinical patellofemoral examination, the precise radiological evaluation of the joint is beneficial in patellofemoral instability patients with concomitant hypermobility. Patient cohort of this study was consist of patients underwent shoulder surgery.     

Medial Patellofemoral Ligament Reconstruction: Indications,Technique, and Outcomes

The medial patellofemoral ligament is the primary static restraint to lateral patellar translation. It is injured in 96% to 100% of patellar dislocations that affect approximately 6 to 29 of 100,000 patients and is more common in patients younger than 20 years of age. Risk factors for patellar dislocation include patella alta, trochlear dysplasia, genu valgus, increased Q angle, and hyperlaxity. The treatment for patellar instability depends on the clinical and radiographic findings and can be nonoperative for first-time dislocations (bracing, proximal strengthening, and progressive return to sport) or operative for recurrent dislocations. It is critical for medial patellofemoral ligament reconstruction to reproduce the anatomy and isometry of the native ligament. Graft choice and methods of fixation are less critical to achieve successful outcomes. Studies have reported successful outcomes and improved Kujala scores, with recurrent instability ranging from 1% to 5%. Careful surgical technique can avoid complications, including fracture, graft failure, loss of range of motion, persistent anterior knee pain, medial instability, and recurrent instability. The role of the medial quadriceps tendon femoral ligament also should be considered more in future research.