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

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

Objective. Overviewing the literature, pain and redislocation after surgical treatment of patellofemoral instability (PFI) is described with up to 30 %, especially with techniques involving the extensor mechanism, the lateral retinaculum or the medial vastus. However, outcome data about revision surgery is missing. Therefore, it was the purpose of this prospective study to evaluate the clinical outcome after revision surgery with an isolated or a combined reco. of the medial patellofemoral ligament (MPFL) with a follow up of 12 months. The indication for additional procedures such as distal femoral osteotomies (DFO), trochleoplasty, reclosing of the lateral retinaculum (RLR) or lateralisation of the tuberosity (LT) were performed depending on the clinical and radiological pathomorphologies. Methods. In between 3/07–4/09, 42 pat. with a mean age of 24 years (13–46ys) were revised due to persistent PFI after mean 1.8 failed previous operations (lateral release, medial gather/VMO-distal., medial. of the tuberosity) in our department. An isolated reco. of the MPFL was performed in 15 cases, while a combination with a DFO due to massive femoral axis deformity (n=5), trochleoplasty due to a convex trochlear morphology (n=1) and/or LT (n=4) and/or RLR due to medial instability or lateral pain (n=22) was done in 27 cases. The clinical result was evaluated by the pre- and postop. IKDC/Kujala/Tegner-score and by a subjective questionnaire. Radiologically, the patellashift/-tilt/-height and level of the eventual degeneration were defined preop. and at the point of follow up with the help of straight lateral radiographs and by MRI. Significance level was set at p=.05, statistical calculation was done by the use of the t-test. Results. 87 % were very satisfied/satisfied with the treatment., None redislocation of the patella occurred during the follow up. We could evaluate a significant decrease of the pain during daily activities. The IKDC/Kujala/Tegner score have shown a significant increase overall. However, a significant difference concerning the scores could not be noticed in between the groups without and with additional procedures. Patellar shift, tilt, height decreased significantly to anatomical values. The level of preexisting degeneration showed no aggravation. Conclusion. Since it is known that PFI is a multifactorial problem, revision surgery should set about only after comprehensive examinations. Regarding our results, isolated or combined MPFL reco. seems to be a very effective treatment of recurrent patella dislocation and results in a significant increase of stability, functionality as well as in a reduction of pain. Additional pathomorphologies of the bony structures or a lateral release, which causes pain or an aggravation of instability, have to be addressed additionally to reach same results like with an isolated therapy. Level of Evidence. II

Objectives. For a long time lateral release (LR) was performed as a standard procedure both, for patellofemoral pain syndrome (PFPS) and patellofemoral instability (PFI). However, recent biomechanical studies have shown that LR is not useful for decreasing the lateral force onto the patella, but is increasing not only medial but also lateral PFI. Furthermore, pain on palpation over the lateral patellofemoral joint space can result in patients treated with extensive LR. We postulate that in case of persistent PFI or PFPS after failed LR the reconstruction of the lateral retinaculum as an addition of the reconstruction of the medial patellofemoral ligament (MPFL) is necessary in terms of decreasing medial PFI as well as lateral pain. Materials and Methods. In between 03/07 and 04/09 we have seen a total of 25 patients (20 f, 5 m) with persistent PFI and palpatory pain over the lateral retinaculum due to unsuccessful treatment of PFI with a LR. These patients have undergone revision surgery with an anatomical reconstruction of the released lateral retinaculum in combination with a reconstruction of the medial patellofemoral ligament (MPFL) in an aperture-technique using the gracilis tendon. The average age at time of operation was 26.2 ± 9.8 years. Preoperatively, as well as 6 weeks, 3 months, 6 months, and 12 months postoperatively, clinical examinations were performed and subjective as well as objective scores (Kujala-, Tegner-, IKDC-score) were evaluated. Regarding radiological parameters measurement of patellar tilt and shift was carried out on axial radiographs before and after the operation. Results. During the first twelve months after the operation only one redislocation could be recorded. Pain on palpation over the reconstructed lateral retinaculum was remaining in four patients (16%). Although several patients complained about persistent patellofemoral pain on exertion or after enduring flexion of the knee, all of them reported about an improvement of their pain situation. This fact is reflected in a highly significant improved but still moderate IKDC- (from 46.5 ± 14.9 to 68.9 ± 22.7, p<0.001) and Kujala-score (from 47.7 ± 15.3 to 74.8 ± 24.8, p<0.001) at the one year follow up. As far as sports activity is concerned, a statistically significant improvement of the Tegner-score up to 4.7 ± 2.4 (preoperative 2.3 ± 1.5, p<0.001) could be achieved. The radiological analysis showed a highly significant decrease of both, patellar tilt (from 15.4 ± 6.5 to 10.3 ± 6.2, p<0.001) and patellar shift (from 4.3 ± 3.3 to 2.5 ± 1.3, p=0.002). Conclusions. After one or more unsuccessful previous efforts of stabilizing the patella by LR, the technique performed in this essay leads to a considerable improvement of subjective scores and objective clinical and radiological parameters as well as sports activity