Introduction. Patellofemoral instability is one of the most common presentations to a children's orthopaedic clinic. Recurrent patellar dislocations and instability episodes are painful, disabling and increase the risk of irreversible chondral damage. The medial patellofemoral ligament is the primary static stabiliser to prevent lateral dislocation of the patella and is almost always torn or attenuated in these cases. Reconstruction of this ligament is commonly performed using autologous hamstring tendon however there has been some interest recently in use of quadriceps tendon as a graft. Children with patellar instability also present unique challenges due to the small size of the patella and the presence of open growth plates which may require adaptations to the common techniques. Methods. Patients undergoing medial patellofemoral ligament reconstruction using quadriceps tendon autograft were identified using electronic theatre records. Prospectively collected clinical records and imaging findings were reviewed and underlying pathology, additional procedures at time of MPFL reconstruction, current function and need for further revision surgery determined. Results. Between January 2019 and August 2023, 50 MPFL reconstructions were performed in 37 children using partial thickness quadriceps autograft. Patient age at time of surgery ranged from 5 to 17 years (median age 13 years). The technique was utilised for a variety of indications including recurrent traumatic and habitual patellofemoral instability, fixed dislocations, and revision MPFL reconstruction. Conclusion. Partial thickness quadriceps tendon autograft can be used safely to primarily reconstruct the medial patellofemoral ligament in paediatric population, including those children with open growth plates. It also has utility in revision cases following previous failed hamstring MPFL reconstruction. We have noted that the younger the child, the more distal to the physis lies the femoral point of isometricity, rendering this a safe and reproducible treatment in this age group. Use of this technique has increased in our unit as we have observed that patients seem to be satisfied with their clinical and functional outcomes with a low incidence of short- and medium-term complications

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 aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach.

Patellofemoral instability (PFI) is a common cause of knee pain and disability in the paediatric population. Patella alta, lateralised tibial tubercle, medial patellofemoral ligament (MPFL) deficiency, genu valgum and trochlear dysplasia are well known risk factors. A prospective database was created including patients referred through our physiotherapy pathway following first-time patella dislocation. Patella alta and lateralisation of the tibial tuberosity was treated with a Fulkerson-type tibial tubercle osteotomy(TTO). Medial patellofemoral ligament was reconstructed using quads tendon autograft pull-down technique. A modified Sheffield protocol was used postoperatively allowing weightbearing in a hinged knee brace. Forty patients were identified with 8 patients having bilateral presentations. Male to female ratio was 12:28 with an age range of 4–17 years. Eight patients had congenital PFI, five patients acquired PFI through traumatic patella dislocation and twenty-seven patients developed PFI from recurrent dislocations. Structural abnormalities were found in 38(95%) of patients. Patella alta (Caton-Deschamps index >1.2) was identified in 19(47%) patients, genu valgum in 12(30%) patients, increased tibial tubercle-trochlear groove distance(TT-TG>20mm) was present in 9(22.5%) patients and persistent femoral anteversion(> 20 deg) in 7(17%) patients. Eight patients were treated with TTO and MPFL reconstruction, three patients with MPFL reconstruction alone and five patients had guided growth for genu valgum correction. Ten patients are awaiting surgery. No postoperative patients had recurrence of PFI at their latest follow up. PFI is a common problem in the adolescent paediatric population with identifiable structural abnormalities. Correcting structural pathology with surgery leads to predictable and safe outcomes

Aims

Tibial tubercle osteotomy (TTO) facilitates surgical exposure and protects the extensor mechanism during revision total knee arthroplasty (rTKA). The purpose of this study was to determine the rates of bony union, complications, and reoperations following TTO during rTKA, to assess the functional outcomes of rTKA with TTO at two years’ minimum follow-up, and to identify the risk factors of failure.

Abstract

Aims

Multiligament knee injuries (MLKI) are devastating injuries that can result in significant morbidity and time away from sport. There remains considerable variation in strategies employed for investigation, indications for operative intervention, outcome reporting, and rehabilitation following these injuries. At present no study has yet provided a comprehensive overview evaluating the extent, range, and overall summary of the published literature pertaining to MLKI. Our aim is to perform a methodologically rigorous scoping review, mapping the literature evaluating the diagnosis and management of MLKI.

Abstract. The radiographic or bony landmark techniques are the two most common methods to determine Medial patellofemoral ligament (MPFL) femoral tunnel placement. Their intra/inter-observer reliability is widely debated. The palpation technique relies on identifying the medial epicondyle (ME) and adductor Tubercle (AT). The central longitudinal artery and associated vessels (CLV) are consistently seen in the surgical dissection during MPFL reconstruction. The aim of this study was to investigate the anatomic relationship of CLV to ME-AT and thereby use CLV as an important vascular landmark during MPFL reconstruction. A retrospective review of MRI scans in skeletally mature patients presenting to a tertiary referral knee clinic was undertaken. Group-N consisted of any presentation without patellofemoral instability or malalignment (PFI). Group-P with PFI. MRI's were reviewed and measured by two Consultant Radiologists for the CLV-ME-AT anatomy and relationship. Following exclusions 50 patients were identified in each group. The CLV passed anterior to the AT and ME in all patients. ME morphology did not differ greatly between the groups except in the tubercle height, where there was a statically but not clinically significant difference (larger in the non-PFI group, 2.95mm vs 2.52mm, p=0.002). The CLV to ME Tip distance was consistent between the groups (Group PFI group 3.8mm & ‘normal’ non-PFI Group 3.9mm). The CLV-ME-AT relationship remained consistent despite patients presenting pathology. The CLV consistently courses anterior to ME and AT. The CLV could be used as a vascular landmark assisting femoral tunnel placement during MPFL reconstruction

Abstract. Patellofemoral Arthroplasty (PFA) is an alternative to TKA for patellofemoral osteoarthritis that preserves tibiofemoral compartments. It is unknown how implant positioning affects biomechanics, especially regarding the patella. This study analysed biomechanical effects of femoral and patellar component position, hypothesising femoral positioning is more important. Nine cadaveric knees were studied using a repeated-measures protocol. Knees were tested intact, then after PFA implanted in various positions: neutral (as-planned), patellar over/understuffing (±2mm), patellar tilt, patellar flexion, femoral rotation, and femoral tilt (all ±6°). Arthroplasties were implemented with CT-designed patient-specific instrumentation. Anterior femoral cuts referenced Whiteside's line and all femoral positions ensured smooth condyle-to-component transition. Knee extension moments, medial patellofemoral ligament (MPFL) length-change, and tibiofemoral and patellofemoral kinematics were measured under physiological muscle loading. Data were analysed with one-dimensional statistical parametric mapping (Bonferroni-Holm corrected). PFA changed knee function, altering extension moments (p<0.001) and patellofemoral kinematics (p<0.05), but not tibiofemoral kinematics. Patellar component positioning affected patellofemoral kinematics: over/understuffing influenced patellar anterior translation and the patellar tendon moment arm (p<0.001). Medially tilted patellar cuts produced lateral patellar tilt (p<0.001) and vice versa. A similar inverse effect occurred with extended/flexed patellar cuts, causing patellar flexion and extension (p<0.001), respectively. Of all variants, only extending the patellar cut produced near-native extension moments throughout. Conversely, the only femoral effect was MPFL length change between medially/laterally rotated components. PFA can restore native knee biomechanics. Provided anterior femoral cuts are controlled and smooth condyle-to-component transition assured, patellar position affects biomechanics more than femoral, contradicting the hypothesis

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.

Aims

Joint registries classify all further arthroplasty procedures to a knee with an existing partial arthroplasty as revision surgery, regardless of the actual procedure performed. Relatively minor procedures, including bearing exchanges, are classified in the same way as major operations requiring augments and stems. A new classification system is proposed to acknowledge and describe the detail of these procedures, which has implications for risk, recovery, and health economics.

Evaluating musculoskeletal conditions of the lower limb and understanding the pathophysiology of complex bone kinematics is challenging. Static images do not take into account the dynamic component of relative bone motion and muscle activation. Fluoroscopy and dynamic MRI have important limitations. Dynamic CT (4D-CT) is an emerging alternative that combines high spatial and temporal resolution, with an increased availability in clinical practice. 4D-CT allows simultaneous visualization of bone morphology and joint kinematics. This unique combination makes it an ideal tool to evaluate functional disorders of the musculoskeletal system. In the lower limb, 4D-CT has been used to diagnose femoroacetabular impingement, patellofemoral, ankle and subtalar joint instability, or reduced range of motion. 4D-CT has also been used to demonstrate the effect of surgery, mainly on patellar instability. 4D-CT will need further research and validation before it can be widely used in clinical practice. We believe, however, it is here to stay, and will become a reference in the diagnosis of lower limb conditions and the evaluation of treatment options.

Cite this article: Bone Joint J 2021;103-B(5):822–827.

Introduction. Recurrent patellar dislocation is often reported in bilateral knees in young active individuals. The medial patellofemoral ligament (MPFL) tear is the attributable cause behind many of them and warrants reconstruction of the ligament to stabilize the patellofemoral joint. Besides, trochleoplasty and Fulkerson's osteotomy are some other procedures that are performed to treat this problem. This study aimed to compare the clinical and functional outcomes in a cohort of patients with single-stage bilateral realignment procedures vs staged procedures. Methods. It was a retrospective matched cohort study with prospectively collected data. A total of 36 patients (mean age-26.9 years, range 13 years to 47 years) with recurrent patellar dislocations, who underwent a surgical correction in both the knees, were divided into two matched groups (age, sex, follow-up, and type of procedure). Among them, 18 patients had surgeries in one knee done at least six months later than the other knee. The remaining 18 patients had surgical interventions for both knees done in a single stage. Lysholm, Kujala, Tegner, and subjective knee scores of both groups were compared and analyzed. The rate of complications and return to the theatre were noted in both groups. Results. With a mean follow-up of 7.3 years (2.0 years to 12.3 years), there was a significant improvement in PROMS observed in both the groups (p<0.05). No significant difference could be found between the two groups in terms of the Lysholm, Kujala, and subjective knee scores (p> 0.05). The rate of complication and the re-operation rate was comparable in both the groups (p>0.05). Conclusion. The outcomes of staged vs simultaneous surgeries for bilateral patellofemoral instability are comparable. Our results indicate that simultaneous bilateral surgical correction is safe. This can potentially be an option to reduce the surgical cost and perioperative morbidity. However, careful selection of cases, choice of the patient, and the scope of rehabilitation facilities are some of the other factors that should be considered

Aims

Trochlear dysplasia is a significant risk factor for patellofemoral instability. The Dejour classification is currently considered the standard for classifying trochlear dysplasia, but numerous studies have reported poor reliability on both plain radiography and MRI. The severity of trochlear dysplasia is important to establish in order to guide surgical management. We have developed an MRI-specific classification system to assess the severity of trochlear dysplasia, the Oswestry-Bristol Classification (OBC). This is a four-part classification system comprising normal, mild, moderate, and severe to represent a normal, shallow, flat, and convex trochlear, respectively. The purpose of this study was to assess the inter- and intraobserver reliability of the OBC and compare it with that of the Dejour classification.

Objectives

The aim of this study was to investigate the biomechanical effect of the anterolateral ligament (ALL), anterior cruciate ligament (ACL), or both ALL and ACL on kinematics under dynamic loading conditions using dynamic simulation subject-specific knee models.

Background of study. Medial patellofemoral ligament (MPFL) reconstructions are often performed using gracilis autografts, this can be associated with donor site morbidity and complications. The use of synthetic material can circumvent a harvest operation and have previously been demonstrated to be effective in other types of reconstructive procedures and may be effective in MPFL reconstruction. We report our experience and clinical results with the use of FiberTape (FT) in MPFL reconstruction and compare it to the same surgical technique using standard autografts. Materials and Methods. Data were collected prospectively in 50 MPFL reconstructions. The first 27 underwent reconstruction using autograft; the following 23 patients were treated with FT. All patients were clinically and radiologically assessed and underwent pre- and post-operative scoring using the Kujala score, Bartlett score, Modified Tegner activity rating scale, SF 12 score and Lysholm score. Statistical significance was tested between groups using ANOVA with repeated measures. Results. There was no significant differences in the pre-operative scores between the FT and GT groups (p>0.05). Both groups showed significant improvement across all scoring modalities between pre- and post-operative periods 12, 24 and 48 months of follow-up (p<0.05). There were no significant differences in knee function scores between the GT and FT groups. Conclusion. The use of FT in MPFL reconstruction is safe and effective, it significantly improved patient's quality of life and related postoperative outcome measures. There were no significant differences in all knee scores compare to GT autografts. Tendon harvesting is unnecessary and FT is a feasible option for MPFL reconstruction

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