Introduction. Trochleoplasty is an effective surgical procedure for patients with severe trochlear dysplasia and recurrent patella instability. Previous work has suggested patients demonstrate early improvements in knee function and quality of life. However, concerns regarding longer term outcomes due to the development of stiffness and patellofemoral osteoarthritis remain a concern for these patients. Our aim was to assess mid-term patient-reported outcome and quality of life measures for trochleoplasty performed at a single centre for severe trochlear dysplasia. Methods. Retrospective review of 28 knees (23 patients) having undergone trochleoplasty for severe trochlear dysplasia were reviewed. Due to the non-parametric nature of the data, median and interquartile range (IQR) were determined for pre-operative and mid-term follow-up scores. Statistically significant differences between groups were assessed using paired Wilcoxon-signed rank test with statistical significance set at p<0.05. Data were analysed using a statistical software package (IBM® SPSS® Statistics 26.0). Results. Median time from surgery to follow-up for all patients in the series was 5.3 years (IQR 3.9 – 7.0 years). Median pre-operative Kujala score improved from 57.0 (IQR 45 – 66) to 96.3 (IQR 83 -100). Median pre-operative IKDC score improved from 42.6 (IQR 35.9 – 51.3) to 92.6 (IQR 71.6 – 98.7). Median EQ-5D score also improved from 0.691 (IQR 0.414 – 0.727) to 1.000 (IQR 0.8178 – 1.000). Improvement in Kujala scores, IKDC scores and EQ-5D were all statistically significant with p<0.001 in all domains. Discussion. Our data suggests patients experience significant improvements in knee function and quality of life following trochleoplasty surgery for severe dysplasia. We demonstrate an absolute improvement in scores at a mean of 5.3 years follow-up of 39.3 points for Kujala, 50 for IKDC and 0.309 for EQ-5D. Minimal clinically important differences (MCID) have been reported to be in the region of 10 for the Kujala score, 8.8–15.6 for IKDC and 0.085 for EQ-5D. Our data shows improvements which far exceed the published MCID, suggesting trochleoplasty confers a large treatment effect and patients benefiting from sustained improvements in knee function and overall quality of life at mid-term follow-up. Conclusion. Following trochleoplasty for severe trochlear dysplasia, patient reported outcomes demonstrate continued improvements in knee function and quality of life at mid-term (5-year) follow-up. There is a large absolute treatment effect which likely impacts on both physical and psychological wellbeing for these patients. Continued surveillance of patient reported outcomes in this clinically complex cohort is indicated

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° to 90° of flexion. Patellar tracking was measured from 0° to 130° 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

Aims. The Bereiter trochleoplasty has been used in our unit for 12 years to manage recurrent patellar instability in patients with severe trochlea dysplasia. The aim of this study was to document the outcome of a large consecutive cohort of patients who have undergone this operation. Patients and Methods. Between June 2002 and August 2013, 214 consecutive trochleoplasties were carried out in 185 patients. There were 133 women and 52 men with a mean age of 21.3 years (14 to 38). All patients were offered yearly clinical and radiological follow-up. They completed the following patient reported outcome scores (PROMs): International Knee Documentation Committee subjective scale, the Kujala score, the Western Ontario and McMaster Universities Arthritis Index score and the short-form (SF)-12. . Results. Outcomes were available for 199 trochleoplasties in 173 patients giving a 93% follow-up rate at a mean of 4.43 years (1 to 12). There were no infections or deep vein thromboses. In total, 16 patients reported further patella dislocation, giving an 8.3% rate of recurrence. There were 27 re-operations, giving a rate of re-operation of 14%. Overall, 88% were satisfied with the operation and 90% felt that their symptoms had been improved. . Conclusion. All PROMs improved significantly post-operatively except for the mental component score of the SF-12. Trochleoplasty performed using a flexible osteochondral flap is an effective treatment for recurrent patellar instability in patients with severe trochlea dysplasia and gives good results in the medium term. Cite this article: Bone Joint J 2017;99-B:344–50

Aims. The aim of this study was to evaluate cartilaginous patellotrochlear congruence and patellofemoral alignment parameters after deepening trochleoplasty in severe trochlear dysplasia. Patients and Methods. The study group comprised 20 patients (two male, 18 female; mean age 24 years (16 to 39)) who underwent deepening trochleoplasty and medial patellofemoral ligament (MPFL) reconstruction for the treatment of recurrent lateral patellar dislocation due to severe trochlear dysplasia (Dejour type B to D). Pre- and postoperative MRI investigations of the study group were compared with MRI data of 20 age- and gender-matched control patients (two male, 18 female; mean age 27 years (18 to 44)) regarding the patellotrochlear contact ratio, patellotrochlear contact area, posterior patellar edge-trochlear groove ratio, and patellar tilt. Results. Preoperatively, all parameters in the study group indicated significant patellar malalignment, including a reduced patellotrochlear contact ratio (mean 0.38 (0.13 to 0.59) vs mean 0.67 (0.48 to 0.88); p < 0.001), reduced contact area (mean 128 mm. 2. (87 to 190) vs mean 183 mm. 2. (155 to 227); p < 0.001), increased patellar lateralization (mean 0.82 (0.55 to 1.0) vs mean 0.99 (0.93 to 1.1); p < 0.001) and increased patellar tilt (mean 25.8° (8.1° to 43.0°) vs mean 9.1° (0.5° to 16.8°); p < 0.001). Postoperatively, all parameters in the study group improved significantly and reached normal values compared with the control group. The patellotrochlear contact ratio increased to a mean of 0.63 (0.38 to 0.85) (p < 0.001), the contact area increased to a mean of 187 mm. 2. (101 to 255) (p < 0.001), the posterior patellar edge-trochlear groove ratio improved to a mean of 0.96 (0.83 to 0.91) (p < 0.001), and the patellar tilt decreased to a mean of 13.9° (8.1° to 22.1°) (p < 0.001) postoperatively. Conclusion. Deepening trochleoplasty and MPFL reconstruction normalized the patellotrochlear congruence and patellofemoral alignment parameters. Modifying the dysplastic trochlea involves approximating the trochlear morphology to the shape of the patella rather than inducing a patella and trochlea mismatch. Cite this article: Bone Joint J 2019;101-B:325–330

Recurrent patellar instability is a common problem and there are multiple demographic and pathoanatomic risk factors that predispose patients to dislocating their patella. The most common of these is trochlear dysplasia. In cases of severe trochlear dysplasia associated with patellar instability, a sulcus deepening trochleoplasty combined with a medial patellofemoral ligament reconstruction (MPFLR) may be indicated. Unaddressed trochlear pathology has been associated with failure and poor post-operative outcomes after stabilization. The purpose of this study is to report the clinical outcome of patients having undergone a trochleoplasty and MPFLR for recurrent lateral patellofemoral instability in the setting of high-grade trochlear dysplasia at a mean of 2 years follow-up. A prospectively collected database was used to identify 46 patients (14 bilateral) who underwent a combined primary MPFLR and trochleoplasty for recurrent patellar instability with high-grade trochlear dysplasia between August 2013 and July 2021. A single surgeon performed a thin flap trochleoplasty using a lateral para-patellar approach with lateral retinaculum lengthening in all 60 cases. A tibial tubercle osteotomy (TTO) was performed concomitantly in seven knees (11.7%) and the MPFLR was performed with a gracilis tendon autograft in 22%, an allograft tendon in 27% and a quadriceps tendon autograft in 57% of cases. Patients were assessed post-operatively at three weeks and three, six, 12 and 24 months. The primary outcome was the Banff Patellar Instability Instrument 2.0 (BPII 2.0) and secondary outcomes were incidence of recurrent instability, complications and reoperations. The mean age was 22.2 years (range, 13 to 45), 76.7% of patients were female, the mean BMI was 25.03 and the prevalence of a positive Beighton score (>4/9) was 40%. The mean follow-up was 24.3 (range, 6 to 67.7) months and only one patient was lost to follow-up before one year post-operatively. The BPII 2.0 improved significantly from a mean of 27.3 pre-operatively to 61.1 at six months (p < 0 .01) and further slight improvement to a mean of 62.1 at 12 months and 65.6 at 24 months post-operatively. Only one patient (1.6%) experienced a single event of subluxation without frank dislocation at nine months. There were three reoperations (5%): one for removal of the TTO screws and prominent chondral nail, one for second-look arthroscopy for persistent J-sign and one for mechanical symptoms associated with overgrowth of a lateral condyle cartilage repair with a bioscaffold. There were no other complications. In this patient cohort, combined MPFLR and trochleoplasty for recurrent patellar instability with severe trochlear dysplasia led to significant improvement of patient reported outcome scores and no recurrence of patellar dislocation at a mean of 2 years. Furthermore, in this series the procedure demonstrated a low rate (5%) of complications and reoperations

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

Introduction and Aims: Dysplasia of the femoral sulcus is one component that may be present in patients presenting with patellar instability. Rarely the dysplasia is so severe that a dome rather than groove is present. Dejour has reported an operation that deepens the groove, unlike the Albee which elevates it. This study reports the development of a modification of the Dejour trochleoplasty reporting the clinical and radiological results. Method: A consecutive case series of the first 15 patients (17 knees) who underwent a trochleoplasty with a minimum one-year follow-up. There were 11 females and four males with an age range from 15 to 47 years old. Nine patients had had previous operations. The pre-operative length of symptoms ranged from one to 30 years. The patellar instability was managed operatively using the Dejour protocol measuring the patellar height, boss height, tibial tubercle-trochlear groove distance and patellar tilt angle. The Kujala score was used for functional assessment and a subjective assessment was also made. CT scans as well as plain films were used for radiological assessment. The operative technique changed in the light of experience from metallic to absorbable screws as the former abraded the patella. Results: The boss height was reduced from an average of 7.5mm to 1mm (normal 0mm). Tracking became normal in 11 knees and had a slight J-shape in six. Seven knees had a mild residual apprehension. Five patients were very satisfied, eight were satisfied, and two were disappointed. The Kujala score improved from an average of 48 to 73 out of 100. Three patients returned to full sports. Eight patients required further operations apart from the removal of metallic screws in 10 knees. Five of these were arthrolysis for stiffness at about six weeks post-operatively. As a result, patients were placed on a continuous passive motion machine for three to four days to avoid this. One patient went on to have autologous chondrocyte implantation for a defect on the lateral femoral condyle involving the tibial surface. This was after a new injury following a return to sports and not in the area affected by the trochleoplasty. Conclusion: Trochleoplasty for severe dysplasia of the femoral sulcus is a developing procedure. It requires careful attention to detail. For a rare condition the results have been gratifying with an acceptable level of complications. It is not recommended that this procedure be performed by general orthopaedic surgeons

Aim: To systematically review the present evidence-base, assessing the clinical and radiological outcomes following trochleoplasty for trochlear dysplasia. Methods: An electronic literature search was performed using the AMED, British Nursing Index, CINAHL, Cochrane, EMBASE, ovid Medline, Physiotherapy Evidence Database, PsycINFO, Pubmed and Zetoc databases from their inception to August 2007. Reference lists of identified papers and a hand search of specialist knee journals was also undertaken. All English language, human subject clinical studies, detailing the clinical and/or radiological outcomes of patellar instability patients following a trochleoplasty were included. Two independent reviewers appraised each paper using the CASP tool. Results: Six papers comprising of 117 trochleoplasty procedures on 99 patients were reviewed. Clinically and radiologically, trochleoplasty was shown to be a safe and effective procedure to correct patellar instability in trochlear dysplasia patients. However, the CASP tool identified that the evidence-base reviewed presented with a number of methodological limitations. These included: limited use of inferential statistics; not applying reliable outcome measurements; poor description of patient recruitment; and evaluating small samples. Conclusion: Although trochleoplasty may be an effective procedure to correct patellar instability in trochlear dysplasia patients, further study is recommended to assess longer-term outcomes using well-designed studies

Trochlear dysplasia is a developmental condition characterised by an abnormally flat or dome shaped trochlea and is an important contributing factor to patellofemoral instability and recurrent patellar dislocation. We prospectively studied a cohort of 54 consecutive patients (59 knees) with patellofemoral instability secondary to trochlear dysplasia, treated with a trochleoplasty by a single surgeon over a 5 year period. Patients were recruited from the senior author's specialist knee clinic and pre-operatively, multiple patient-centred scores were recorded. After the trochleoplasty, these were repeated along with a patient satisfaction questionnaire. Of the 54 patients and 59 knees operated, 39 of the patients (44 knees) were female and 15 (15 knees) male and 40 patients (42 knees) had follow-up of 12 months or more. Their mean age at surgery was 21 years and 6 months and mean length of follow up 2 years. One patient was unable to attend for follow up due to the development of a pelvic Ewings sarcoma. A statistically significant improvement in outcomes was demonstrated when the pre and post-operative scores were compared (mean scores of Oxford 26 to 19, WOMAC 23 to 17, IKDC 54 to 72, Kujala 62 to 76, Lysholm 57 to 78, p values <0.001 for all scores). 93% (50 patients) were satisfied with the outcome of their procedure. We conclude that in the short and medium term, the results of trochleoplasty are encouraging in this challenging group of patients

Purpose: Trochlea dysplasia is a developmental condition characterized by an abnormally flat or dome shaped trochlea. This predisposes to recurrent patella instability. This study prospectively reviews the early results of patients undergoing a trochleoplasty procedure which corrects the dysplastic anatomical abnormality. Patients and Methods: All patients were recruited from the senior author’s (JDJE) specialist knee clinic following the standard patellofemoral assessment. Patients were seen pre-operatively to collect epidemiological data, ensure completion of patient reported assessment forms and document clinical examination findings and investigations. Duration of instability and previous procedures performed for patella instability were recorded. Multiple patient-reported outcome measures were recorded. Outcome score assessments and clinical examinations were repeated post-operatively, along with a patient satisfaction questionnaire. All operations were carried out by the senior author with supplementary procedures based on pre-operative assessment. Results: 22 patients had a minimum of 12 months follow-up. The average age was 21 years and the average duration of instability symptoms (pre-trochleoplasty) was 7 years. There were 16 females and 6 males. Mean follow up was 18 months. Patients reported improvement in outcome when the pre and post-operative scores were compared (mean scores of Oxford 34 to 41, WOMAC 23 to 15, Kujula 62 to 79, IKDC 62 to 81, and Lysholm 57 to 77). The patient satisfaction questionnaire revealed just one patient not satisfied with the procedure despite good patient reported outcome scores. The majority of patients perceived improvement due to the surgery and agreed they would recommend the procedure to others despite some residual symptoms. Recurrent instability after trochleoplasty was rare (one subluxation) and range of movement was uniformly excellent. Conclusion: Early results of this trochleoplasty for patients with trochlea dysplasia and symptomatic recurrent patella instability are encouraging

Purpose Of The Study: Description of a new operative technique of trochleoplasty for patellar instability and its short-term results. Method: we report a new technique of trochleoplasty for Trochlear dysplasia, using Mitek anchor sutures. The purpose of the procedure is to remove the anterior femoral boss associated with Femoral Trochlear dysplasia and make the floor of the trochlea level with the anterior femoral cortex. The operation entails undermining of the trochlear and lateral condylar articular cartilage to a new corrected level where it is held with the use of No 2 Ethibond Mitek anchor sutures. These anchors are placed in the subchondral bone, suture needle passed through the articular cartilage and the sutures tied over it. Approximately 4 -5 anchor sutures are placed to hold the trochlear cartilage down to the new corrected level. This procedure can be combined with proximal and distal patellar realignment. So far, using this technique, we have operated on six patients with trochlear dysplasia and chronic patellar instability. The patients include 4 females and 2 male with an average age of 33 yrs (range 29 – 40). Average follow up is 16 months (range 8 – 24 months). There has not been any recurrence of patellar instability in the operated patients. Conclusion: Short-term follow up of a new operative technique of troachleoplasty for patellar instability shows promising results

Introduction. The dysplastic trochlear is a developmental condition characterized by an abnormally flat or dome-shaped trochlea and it is recognized as a significant cause of patella instability. Surgical correction of the shape of the Trochlear Groove is frequently performed. The described methods in the literature involve open arthrotomy to normalize and maintain the trochlear morphology achieving normal alignment and tracking of the patella. Material, methods and results. Open procedures carries a significant risk of arthrofibrosis. We describe an arthroscopic procedure to create a neo-trochlea using gouges, spherical and conical hooded burrs. We studied prospectively a series of 4 consecutive patients with patello-femoral instability secondary to trochlear dysplasia, who were treated by an Arthroscopic trochleoplasty by a single surgeon between 2007 and 2008. Postoperatively the patients were rehabilitated in accordance with our routine Patello-Femoral microfracture protocol. CT scanning at one year showed a complete neo-cortex and cartilage sequenced MRI at 12 months showed complete fill with fibro cartilage. Pre- and post-operative scores (KOOS, Kujala) were assessed by the patients and a satisfaction questionnaire was completed. The results showed a statistical improvement in the outcome at the 3 year follow up. Conclusion. Overall, patients (100%) were satisfied with the outcome of their procedure and there have been no adverse events. To our knowledge this technique has not been described before in the English literature and the early results of arthroscopic trochleoplasty are encouraging and offer an alternative to open approaches. Larger numbers and longer follow ups are needed to confirm the long term benefit

The dysplastic Trochlear is a developmental condition characterised by an abnormally flat or dome-shaped trochlea and it is recognised as a significant cause of patella instability, with the increased sulcus angle being is the most common finding. Surgical correction of the shape of the Trochlear Groove is frequently performed. The described methods in the literature involve open arthrotomy to normalise and maintain the trochlear morphology achieving normal alignment and tracking of the patella. Open procedures carries a significant risk of arthrofibrosis. The technique was developed in human cadaveric knees at the Donjoy Clinical Education and Research Facility (CERF) in Vista California. We describe an arthroscopic procedure to create a neo-trochlea using gouges, spherical and conical hooded burrs. We studied prospectively a series of 4 consecutive patients with patello-femoral instability secondary to trochlear dysplasia, who were treated by an Arthroscopic trochleoplasty by a single surgeon between 2007 and 2008. Postoperatively the patients were rehabilitated in accordance with our routine Patello-Femoral microfracture Protocol, allowing weight bearing and ROM 0-20 degrees in a long lever brace for 6 weeks. CT scanning at one year showed a complete neo-cortex and cartilage sequenced MRI at 12 months showed complete fill with fibro cartilage. Pre- and post-operative scores (KOOS, Kujala) were assessed by the patients and a satisfaction questionnaire was completed. The results showed a statistical improvement in the outcome at the 2 year follow up. Overall, patients (100%) were satisfied with the outcome of their procedure and there have been no adverse events. To our knowledge this technique has not been described before in the English literature and the early results of arthroscopic trochleoplasty are encouraging and offer an alternative to open approaches. Larger numbers and longer follow ups are needed to confirm the long term benefit

Introduction: The purpose was to present a new osteotomy technique (trochleoplasty) and its preliminary results for the treatment of femoral trochlear dysplasia with recurrent patellar dislocation. Methods: Between 1990 and 2002, 59 knees of 51 patients (mean age 224 years) with recurrent patellar dislocation due to femoral trochlear dysplasia were treated uniformly at a single institution with a new osteotomy technique developed by the senior author. A distally connected osteochondral flake is released from the dysplastic trochlea and refixed after the osseous trochlear groove has been reconstructed. 44 patients with 50 involved knees returned at a mean follow-up of 37 months (range 6 to 139) for a physical examination, assessment of knee pain and function, radiographic examination of the knee, and in selectived cases for CT scan, MR imaging and follow-up knee arthroscopy. Results: Postoperative complications were limited to hemarthros-1, arthrofibrosis-1, and sudeck‘s disease-1. Postoperatively, no further patellar dislocations were reported. All patients experienced a sensation of significantly improved knee stability resulting in higher levels of activity. Retropatellar pain as found in 34 knees preoperatively was better-24, unchanged-7, worse-6 (3 additional cases) after surgery. Positive apprehension sign, as preoperatively found in all patients, turned negative in all cases. Radiographically, osseous healing of the reconstructed trochlea was noted without evidence of subsequent arthrosis. MRI and knee arthroscopy including histological analysis of osteochondral biopsies did not provide any evidence for osteonecrosis or chondropathia. Conclusion: Recurrent patellar dislocation due to femoral trochlear dysplasia can be treated successfully using the presented technique of trochleoplasty

Aims

The Oswestry-Bristol Classification (OBC) was recently described as an MRI-based classification tool for the femoral trochlear. The authors demonstrated better inter- and intraobserver agreement compared to the Dejour classification. As the OBC could potentially provide a very useful MRI-based grading system for trochlear dysplasia, it was the aim to determine the inter- and intraobserver reliability of the classification system from the perspective of the non-founder.

The aim of this study is to document the outcome of a large cohort of patients treated with the Bereiter trochleoplasty with between 1 and 12 years of follow up.

215 consecutive cases in 186 patients were recorded prospectively. All patients were offered yearly clinical and radiological review. PROMs were recorded including the IKDC, OKS, Kujala and SF-12. Patients unable to attend clinic were assessed with PROMS and radiographs from their local institutions where possible.

There were 133 females and 53 males, with a mean age of 21 (14–38). There were no infections and only 6 patients reported further dislocations. There was one flap breakdown and no identified cases of secondary osteoarthritis. PROMs were available for 194 cases in 167 patients (90% follow up). 84% of patients were satisfied, 87% felt their symptoms had improved and 69% had gone back to sport. All scores improved (all p<0.001) except for the SF-12 mental score (p=0.42), with averages comparable to the results of MPFL reconstruction.

Good outcomes were observed despite the difficult patient population in which these cases were performed. The Bereiter trochleoplasty is an effective method of treating recurrent patella instability in patients with severe trochlea dysplasia.

Aims. The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process. Methods. This was the second part of a study dealing with these aspects of management in these patients. As in part I, a total of 60 surgeons from 11 countries contributed to the development of consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered unanimous. Results. Of 41 questions and statements on patellar instability, none achieved unanimous consensus, 19 achieved strong consensus, 15 achieved consensus, and seven did not achieve consensus. Conclusion. Most statements reached some degree of consensus, without any achieving unanimous consensus. There was no consensus on the use of anchors in MPFL reconstruction, and the order of fixation of the graft (patella first versus femur first). There was also no consensus on the indications for trochleoplasty or its effect on the viability of the cartilage after elevation of the osteochondral flap. There was also no consensus on postoperative immobilization or weightbearing, or whether paediatric patients should avoid an early return to sport. Cite this article: Bone Joint J 2023;105-B(12):1265–1270

Aims. The Oswestry-Bristol Classification (OBC) is an MRI-specific assessment tool to grade trochlear dysplasia. The aim of this study is to validate clinically the OBC by demonstrating its use in selecting treatments that are safe and effective. Methods. The OBC and the patellotrochlear index were used as part of the Oswestry Patellotrochlear Algorithm (OPTA) to guide the surgical treatment of patients with patellar instability. Patients were assigned to one of four treatment groups: medial patellofemoral ligament reconstruction (MPFLr); MPFLr + tibial tubercle distalization (TTD); trochleoplasty; or trochleoplasty + TTD. A prospective analysis of a longitudinal patellofemoral database was performed. Between 2012 and 2018, 202 patients (233 knees) with a mean age of 24.2 years (SD 8.1), with recurrent patellar instability were treated by two fellowship-trained consultant sports/knee surgeons at The Robert Jones and Agnes Hunt Orthopaedic Hospital. Clinical efficacy of each treatment group was assessed by Kujala, International Knee Documentation Committee (IKDC), and EuroQol five-dimension questionnaire (EQ-5D) scores at baseline, and up to 60 months postoperatively. Their safety was assessed by complication rate and requirement for further surgery. The pattern of clinical outcome over time was analyzed using mixed regression modelling. Results. In all, 135 knees (mean age 24.9 years (SD 9.4)) were treated using a MPFLr. Ten knees (7.4%) required additional surgery. A total of 50 knees (mean age 24.4 years (SD 6.3)) were treated using MPFLr + TTD. Ten (20%) required additional surgery. A total of 20 knees (mean age 19.5 years (SD 3.0)) were treated using trochleoplasty + TTD. Three patients (15%) required additional surgery. In each treatment group, there was a significant improvement in Kujala, IKDC, and EQ-5D at one year postoperatively (p < 0.001) with a recognized level of overall complication rate. Conclusion. The OBC is a valid assessment tool to grade patients with trochlear dysplasia and, when used as part of the OPTA, helps to determine treatments that are safe and effective. This fulfils the requirements for its application in mainstream clinical practice. Cite this article: Bone Joint J 2021;103-B(10):1586–1594

A risk factor for patellofemoral instability is trochlear dysplasia. Trochleoplasty is a surgical procedure used to reshape the trochlear groove to improve patellar stability. This study seeks to compare pre-op MRI measurements and post operative MRI measurements for patients who have undergone trochleoplasty in correlation with their clinical outcomes scores. Data was collected from a database of patients known to have trochlear dysplasia who underwent trochleoplasty. Radiological Data was collected pre-op and subsequent post op MRI data collected included TT-TG, Patella Tilt, IS, sulcus angle. Data score sheets pre-op and post op trochleoplasty completed by patients were also collected. 10 patients had pre and post op MRI's documented. 80%(8/10) females and 20%(2/10) males, average age of 30 years old (range 23 – 32 years old). Average MRI pre-op scores: IS ratio: 1.2, Patella tilt: 24.14, sulcus angle 160.13, and TT-TG distance of 16.94. 1 year average MRI post-op scores: IS ratio: 1.28, Patella tilt 15.56, sulcus angle 148.66 and TT-TG distance 16.78. 1 year post op Kujala and Norwich instability scores patient reported improved stability, function and confidence post op compared to pre-op. Subjective and objective scores reflected an improvement of stability. MRI demonstrated a deeper trochlear groove post-operatively which should provide resistance against lateral patella movement and patellar dislocations. TT-TG pre and post op remained constant. Pre op and post op Kujala scores reflected improved function. The Norwich instability scores pre and post op reflected satisfaction of treatment. There are not a lot of studies published on trochleoplasty. Based on this study it is clear that patients with patellofemoral instability with severe trochlear dysplasia will benefit from trochleoplasty. The sample size of the data analysis was only 10. However it reflected that function 1 year post procedure remained stable

The June 2013 Knee Roundup. 360 . looks at: knee arthroplasty in diabetic patients; whether TKR is a timebomb; the use of antidepressants for knee OA; trochleoplasty; articulated spacers; mental health and joint replacement; and the use of physiotherapy for meniscal tear