Patellofemoral Ligament Reconstruction Research Articles

Medial patellofemoral ligament reconstruction using a digital tensiometer to determine graft tension: Surgical technique and mid-term follow-up.

The optimal method for achieving proper graft tension during patellofemoral ligament reconstruction is a topic of debate. In the past, a digital tensiometer was used to simulate the knee structure, and a tension of approximately 2N was identified as suitable for restoring the patellofemoral track. However, it is unclear whether this tension level is sufficient during the actual surgery. The objective of this study was to verify the efficacy of graft tension using a digital tensiometer for medial patellofemoral ligament (MPFL) reconstruction and to conduct a mid-term follow-up. The study enrolled 39 patients who had experienced recurrent patellar dislocation. Preoperative computed tomography scans and X-rays confirmed patellar instability, patellar tilt angle patellar congruence angle and the history of dislocation and patellar apprehension test. Knee function was evaluated using preoperative and postoperative Lysholm and Kujala scores. The study included 39 knees, comprising 22 females and 17 males, with an average age of 21.10 ± 7.26. The patients were followed up for at least 24months through telephone or face-to-face questionnaires. All patients had a preoperative history of ≥2 patellar dislocations, none of which were surgically treated. During surgery, all patients underwent isolated MPFL reconstruction and lateral retinacula release. The mean Kujala and Lysholm scores were 91.28 ± 4.90 and 90.67 ± 5.15, respectively. The mean PTA and PCA were 11.5 ± 2.63 and 2.38 ± 3.58, respectively. The study found that a tension of approximately 27.39 ± 5.57N (14.3-33.5N) was required to restore the patellofemoral track in patients with recurrent patellar dislocation. No patients required reoperation during the follow-up period. Overall, 36 out of 39 patients (92.31%) reported no pain when completing daily activities at the last follow-up. In conclusion, a tension level of approximately 27.39 ± 5.57N is necessary to restore normal patellofemoral relationships during clinical practice, which indicates that using a tension of 2N is too low. The use of a tensiometer during patellofemoral ligament reconstruction is a more accurate and reliable surgical procedure for treating recurrent patellar dislocation.

Influence of the Fluoroscopy Setting towards the Patient When Identifying the MPFL Insertion Point.

(1) The malposition of the femoral tunnel in medial patellofemoral ligament (MPFL) reconstruction can lead to length changes in the MPFL graft, and an increase in medial peak pressure in the patellofemoral joint. It is the cause of 36% of all MPFL revisions. According to Schöttle et al., the creation of the drill canal should be performed in a strictly lateral radiograph. In this study, it was hypothesized that positioning the image receptor to the knee during intraoperative fluoroscopy would lead to a relevant mispositioning of the femoral tunnel, despite an always adjusted true-lateral view. (2) A total of 10 distal femurs were created from 10 knee CT scans using a 3D printer. First, true-lateral fluoroscopies were taken from lateral to medial at a 25 cm (LM25) distance from the image receptor, then from medial to lateral at a 5 cm (ML5) distance. Using the method from Schöttle, the femoral origin of the MPFL was determined when the femur was positioned distally, proximally, superiorly, and inferiorly to the image receptor. (3) The comparison of the selected MPFL insertion points according to Schöttle et al. revealed that the initial determination of the point in the ML5 view resulted in a distal and posterior shift of the point by 5.3 mm ± 1.2 mm when the point was checked in the LM25 view. In the opposite case, when the MPFL insertion was initially determined in the LM25 view and then redetermined in the ML5 view, there was a shift of 4.8 mm ± 2.2 mm anteriorly and proximally. The further positioning of the femur (distal, proximal, superior, and inferior) showed no relevant influence. (4) For fluoroscopic identification of the femoral MPFL, according to Schöttle et al., attention should be paid to the position of the fluoroscopy in addition to a true-lateral view.

Patient perception of medial patellofemoral ligament reconstruction on Instagram

To date, there is limited social media evaluation of patients after medial patellofemoral ligament (MPFL) reconstruction and analysis of their perceived surgical outcome. The purpose of this study was to examine patient perceived outcomes after MPFL reconstruction via social media analysis on Instagram. A total of 486 posts containing “#MPFL” were included in the assessment. The tone of the post was examined in relation to demographic variables and the content of the post. When comparing posts containing positive vs. negative tone, those referencing rehabilitation (P < 0.0001) and activities of daily living (ADLs) (P = 0.0002) were more likely to be positive. Posts referencing surgical incision or scar (P = 0.02) or postoperative instability/dislocation (P < 0.0001) were more likely to have a negative tone. Multivariable logistic regression identified references to incision/scar (odds ratio [OR]: 0.446, P = 0.0264) and instability/dislocation (OR: 0.071, P < 0.0001) as strong negative predictors of positive tone. However, referencing rehabilitation (OR: 2.464, P = 0.0091) or ADLs (OR: 2.251, P = 0.0187) substantially increased the likelihood of a positive post tone. In conclusion, positive tone was associated with improved rehabilitation and ability to perform ADLs postoperatively. In contrast, negative tone was associated with dissatisfaction with the scar/incision, as well as postoperative patellar instability.

Patellar Dislocation and Fracture After Medial Patellofemoral Ligament Reconstruction in a Patient With Osteogenesis Imperfecta

Background: Patellar instability is a common orthopedic condition in the pediatric population. Many factors contribute to patellar instability, including trochlear dysplasia. However, patellar instability and its treatments are not well documented in the literature for patients with osteogenesis imperfecta.Case Report: After medial patellofemoral ligament (MPFL) reconstruction, a 17-year-old male with osteogenesis imperfecta had a patellar dislocation that resulted in a patellar fracture. The patient subsequently had a revision of his MPFL reconstruction, and at 2½ years postoperation has had no episodes of recurrent patellar instability.Conclusion: The combination of bone fragility, trochlear dysplasia, and strength of the allograft used for MPFL reconstruction compared to the patient's bone strength led to dislocation and patellar fracture. Research into alternative methods for patellar fixation and postoperative physical therapy protocols for patients with osteogenesis imperfecta is needed. Special considerations must be made for this patient population.

MPFL reconstruction and tibial tuberosity transposition in patients with patellar instability: May it troubleshots also trochlear dysplasia?

PurposeThis study aimed to highlight short- and medium-term outcomes of combined medial patello-femoral ligament (MPFL) reconstruction and anterior tibial tuberosity (ATT) transposition surgery in patients with recurrent patellar instability and different degrees of trochlear dysplasia.MethodsBetween January 2014 and May 2019, 25 patients with patellar instability underwent a surgical procedure combining the lowering/transposition of the ATT and the MPFL reconstruction. Each patient were preoperative assessed by Kujala score, International Knee Documentation Committee (IKDC), Tegner activity level scale. The assessment of instability predisposing factors was carried out with patellar height, tibial tuberosity-trochlear groove (TT-TG) distance, trochlear dysplasia, sulcus angle, patellar tilt and MPFL injuries. Functional outcomes were evaluated with Kujala, IKDC and Tegner scores at 3, 6 and 12 months after surgery.ResultsThe average age of the patients was 20 years (range 13–43 years). Pre- operative Caton–Deschamps index was pathological in 10 (40%). Sulcus angle was elevated in 13 patients (52%) and TT-TG distance was irregular in 17 patients (68%). Trochlear dysplasia was present in 13 patients (9 type A, 3 type B, 1 type C according to Dejour’s Classification). No re-dislocation occurred during the follow-up. There was a significant increase in the Kujala, IKDC and Lysholm scores after 3, 6 and 12 months, and the results were compared for the different follow-up times and patient’s trochlear dysplasia degree.ConclusionThis prospective observational longitudinal study identified good clinical outcomes in patients who underwent MPFL reconstruction and ATT transposition for patellar instability. Finally, the different risk factors for patellar instability examined, particularly the presence of trochlear dysplasia, did not significantly influence the final functional results, which range from good to excellent without re-dislocation episodes.

MPFL Reconstruction, 3 Years After the Goldthwait Patellar Tendon Hemi-transfer and Vastus Medialis Oblique Advancement, Performed to Treat Recurrent Patellar Instability: A Case Report

The treatment of patellar instability in skeletally immature patients is challenging for an orthopedic surgeon. We report a case of a 14 years old girl who after an acute traumatic dislocation of the left patella and the failed initial conservative treatment underwent medial patellofemoral ligament (MPFL) reconstruction, using the fascia lata as an autograft. At the age of 10, the Roux-Goldthwait patellar tendon hemi-transfer combined with lateral retinacular release and the advancement of the vastus medialis oblique was performed for the treatment of the recurrent patella dislocation of both her knees. The patient evaluated for re-dislocation risk factors using the patellar instability severity score proposed by Balcarek et al. The clinical evaluation of the patient included the modified Cincinnati rating system and the Kujala score. The imaging assessment included knee MRI for the identification of anatomical risk factors. The four anatomical risk factors, trochlear dysplasia, increased tibial tubercle to trochlea groove offset, patella alta, and patellar tilting > 20°, were identified on MRI. At the final follow-up, the mean modified Cincinnati score increased from 49 to 90 points 6 years postoperatively. The mean Kujala scores increased from 49 to 91 points postoperatively. The MPFL reconstruction is an effective treatment to restore patellar stability in skeletally immature patients who underwent less successful surgeries to treat a recurrent patella dislocation.

A computed tomography cadaveric study of the radiological anatomy of the patella: the size of the patella correlates with bone bridge between tunnels and R angles are introduced for safe tunnel drilling during MPFL reconstruction

PurposeTo measure the safe range of angles during tunnel drilling and map ideal patella tunnel placement with the use of preoperative computed tomography (CT) scan and compare results after medial patellofemoral ligament (MPFL) reconstruction using a hardware-free patellar fixation technique with two semi-patellar tunnels between a) a free-hand technique, and b) its modification with the use of an anterior cruciate ligament (ACL) tibia aiming device.MethodsCT scan was performed on 30 fresh-frozen cadaveric knees a) prior to any intervention and b) after MPFL reconstruction. For MPFL reconstruction, specimens were randomly allocated to 1) Group A, which consisted of knees operated with free-hand, hardware-free patellar fixation technique with two semi-patellar tunnels and 2) Group B, which consisted of knees operated on with a technique modification with the ACL tibia device.Patellar measurementsL1 was the maximal patellar length. L2 was the minimum possible distance of placement for the upper tunnel from the proximal pole of the patella. The maximum bone bridge between tunnels was calculated as half of L1 minus the L2 distance (L1/2-L2). We also measured R1 and R2 angles at the proximal and distal tunnel that represent safe angles at the entry point during tunnel drilling (without breaching the anterior cortex or articular cartilage).ResultsPreoperatively, mean L1 was 3.45 cm (range 3.05–4.52). Mean L2 was 0.62 cm (range 0.49–0.89). The mean maximum possible bone bridge between tunnels (L1/2-L2) was 1.1 cm (range 0.77–1.58).R1 was 6.050 (range 4.78–7.44), R2 was 6.640 (range 4.57–9.03), and their difference reached statistical significance (p = 0.03). Postoperatively, in group A, in 4 out of 15 patellas, multiple attempts were made during tunnel drilling in order to avoid anterior cortex or cartilage breaching. In group B, all tunnels were correctly drilled with the first attempt. Bone bridge between tunnels was significantly shorter postoperatively (0.93 cm, p < 0.01).ConclusionSmall-size patellae correlate with short maximum bone bridge between tunnels, which makes anatomic, double-bundle, hardware-free patella fixation, with two semi-patellar tunnels MPFL reconstruction challenging. Furthermore, R angles create a narrow window to avoid intraoperative breaching, rendering the use of the ACL tibia device an extremely useful instrument.Level of evidenceII

Studies of the criteria for determining optimal location of medial patellofemoral ligament attachment sites.

Identifying appropriate attachment sites is important in the planning of medial patellofemoral ligament (MPFL) reconstruction. Two criteria are advanced to describe normal MPFL function, namely isometric criterion and desired pattern criterion. Subsequently, computational methods have applied these criteria to determine optimal attachment sites. So far, there is no study that compares the outcomes of these two criteria. For five subjects' 3D models of the patella and femur, three patellar sites and many femoral sites were identified as pairs of candidate attachment sites. For each patellar site, the criteria were applied to identify the matching femoral sites that satisfy them. The matching femoral site with the smallest length change was identified as the optimal femoral site. The desired pattern criterion finds fewer matching sites compared to the isometric criterion. In contrast, the isometric criterion can always find matching sites. The optimal femoral sites obtained vary significantly across different subjects. For most subjects, the optimal sites obtained using the isometric criterion are closer to known anatomical sites than those obtained using the desired pattern criterion. This study reaffirms that MPFL reconstruction is subject specific. The isometric criterion may be more reliable than the desired pattern criterion for determining optimal attachment sites. Graphical Abstract. Highlight of the paper. The location of the patella site significantly affects the location of the optimal femoral site. The isometric criterion option 1, with length at 0° regarded as MPFL's natural length, may be more reliable than other criteria or options for the planning of MPFL surgery because the optimal sites that it finds are closest to known anatomical sites.ᅟ.

Comparation and evaluation of the accuracy of the sulcus localization method to establish the medial patellofemoral ligament femoral tunnel: a cadaveric and clinical study

BackgroundIn anatomic medial patellofemoral ligament (MPFL) reconstruction, malpositioning of the MPFL femoral tunnel is common. A palpable sulcus reportedly exists at the anatomic femoral attachment of the MPFL. The present study aimed to investigate the accuracy of the sulcus localization method to establish the MPFL femoral tunnel.MethodsA cadaveric study was first done on 12 knees to evaluate the accuracy of the sulcus localization method to establish the entry points of the MPFL femoral tunnel in comparison with the midpoint and fluoroscopic localization methods. The center of the native MPFL femoral attachment was served as the reference in the cadaveric study. A clinical study was then performed to further evaluate the accuracy of the sulcus localization method in 53 patients (60 knees). Schöttle’s point was served as the reference in the clinical study. Femoral tunnel placement was defined as accurate when it was less than 5 mm from Schöttle’s point. In both the cadaveric and clinical studies, MPFL femoral tunnel placement was assessed on postoperative reconstructed three-dimensional computed tomography images. In the cadaveric study, the accuracy of different localization methods was compared using analysis of variance.ResultsIn the cadaveric study, the mean distances from the native MPFL attachment to the femoral tunnel entry point were 4.2 ± 1.0 mm (range 2.4–5.6 mm), 4.4 ± 1.4 mm (range 1.8–6.6 mm) and 2.9 ± 0.8 mm (range 1.9–4.4 mm) using the midpoint, fluoroscopic, and sulcus localization methods, respectively; this distance significantly differed between the midpoint and sulcus localization methods, and between the fluoroscopic and sulcus localization methods (p ≤ .05). While there were no significant differences between the midpoint and fluoroscopic localization methods (n.s.). In the clinical study, the mean distance between the femoral tunnel and Schöttle’s point was 3.5 ± 1.5 mm (range 0.4–6.1 mm), with accurate tunnel placement achieved in 49 of 60 cases (82%).ConclusionThe sulcus localization method can accurately guide MPFL femoral tunnel placement. This method might be useful for orthopedic surgeons.Level of evidenceIV

Radiographic images are inapplicable for a precise evaluation of the femoral tunnel position following MPFL reconstruction.

In medial patellofemoral ligament (MPFL) reconstruction, it remains controversial whether more accurate femoral tunnel positioning is correlated with improved clinical outcomes. The purpose was to verify the accuracy of methods for evaluating tunnel positioning, one of which is the use of postoperative radiographs, in determining the femoral tunnel position following MPFL reconstruction and to compare the variability of tunnel positions to the intraoperatively documented positions on a true-lateral view. Seventy-three consecutive MPFL reconstructions were prospectively enrolled. Femoral tunnel positions were intraoperatively determined using fluoroscopy to obtain true-lateral radiographs. Postoperatively, lateral radiographic images were taken. Seven independent radiologists and seven independent orthopaedic knee surgeons evaluated the femoral tunnel position and amount of malrotation for each radiograph. Deviations from the Schoettle's point were measured and repeated after 4weeks. Intraobserver and interobserver analyses of variance were calculated to determine the reliability of measurements on both intraoperative and postoperative radiographs. Fifty-six patients were included in the final analysis. Tunnel positions were unable to be identified on postoperative radiographs in 14% of cases on average, independent of the degree of radiograph rotation. Intraoperative images showed mean deviations from the tunnel position to the centre of Schoettle's point of 1.9 ± 1.4mm and 1.6 ± 1.0mm in anterior-posterior and proximal-distal direction, respectively. Postoperative radiographs showed mean anterior-posterior and deviations of 7.4 ± 4.4mm and 8.9 ± 5.8mm assessed by orthopaedic surgeons and 10.6 ± 6.3mm and 11.6 ± 7.1mm assessed by radiologists at first and repeated measurement, respectively. The mean proximal-distal deviations were 4.8 ± 4.4mm and 6.5 ± 6.0mm and 7.2 ± 6.3mm and 8.1 ± 7.1mm, respectively. Measurement of tunnel position on intraoperative fluoroscopic images was significantly different compared to postoperative radiographs for each of the 14 observers (p < 0.05). Significant intraobserver and interobserver differences between the first and repeat measurements for both orthopaedic surgeons and radiologists were observed (p < 0.05). Measurement of the femoral tunnel position on postoperative lateral radiographs is not an accurate or reliable method for evaluating tunnel position after MPFL reconstruction due to exposure, contrast, and malrotation of the radiograph from a true-lateral image. In contrast, intraoperative fluoroscopic control allows for a precise lateral view and correct tunnel positioning. Thus, postoperative radiographic images may be unnecessary for the evaluation of femoral tunnel positions, particularly when intraoperative fluoroscopy has been used. Level II, prospective cohort study.

Preliminary results of Combined Medial Patellofemoral and Patellotibial Ligament Reconstruction in recurrent patellar dislocation

Preliminary results of Combined Medial Patellofemoral and Patellotibial Ligament Reconstruction in recurrent patellar dislocation

The Outcomes of Medial Patellofemoral Ligament (MPFL) Reconstruction in Patellofemoral Instability: A Systematic Review and Meta-Analysis

The Outcomes of Medial Patellofemoral Ligament (MPFL) Reconstruction in Patellofemoral Instability: A Systematic Review and Meta-Analysis

Does Ligamentous Laxity Protect Against Chondral Injury in Patients with Patellofemoral Instability?

Objectives:Hypermobility may be a risk factor for musculoskeletal injuries during sports participation. However, we have seen a low incidence of chondral injuries requiring treatment in patients undergoing medial patellofemoral ligament (MPFL) reconstruction for patellofemoral instability. It is unknown if patients with ligamentous laxity, who are at an increased risk for patellofemoral instability, are somewhat protected from chondral injury. We hypothesize in patients undergoing MPFL reconstruction for patellofemoral instability, patients with ligamentous laxity will be less likely to have chondral defects requiring surgical intervention.Methods:171 patients (32 male, 139 female) average age 22 years (range 11-57) with patellofemoral instability were rated with the Beighton-Horan (BH) scale for constitutional ligamentous laxity (0-9). Preoperative MRIs were evaluated (chondral injury present/absent, size of chondral injury, Outerbridge grade) and intra-operative arthroscopic findings noted (chondral injury present/absent, size of chondral injury, Outerbridge grade, surgical intervention yes/no, type of surgical intervention) of 79 non-lax (BH<6) and 92 ligamentously lax patients (BH≥6) (LAX) undergoing MPFL reconstruction. Anatomic measurements were documented for each patient including: tibial tubercle-trochlear groove (TT-TG) distance, Caton-Deschamps (C/D) ratio for patellar height, and the Dejour classification of trochlear dysplasia. Surgical interventions included chondroplasty, microfracture, particulated juvenile cartilage implantation (DeNovo, Zimmer, Warsaw, IN), osteochondral fracture fixation or osteochondral allograft transplantation (OATS).Results:58/171 (33.9%) required a surgical intervention for a chondral defect: chondroplasty 29/58 (50%), microfracture 16/58 (27.6%), particulated juvenile cartilage implantation 18/58 (31%), osteochondral fracture fixation 2/58 (3.5%), and OATS 2/58 (3.5%). There was no difference in the proportion of additional procedures in LAX vs. non-lax (p=0.475). There was no difference in the proportion of patellar chondral injuries sustained (LAX 29.3% vs. non-lax 45.7%) (p=0.538) but LAX patients had a lower proportion of patellar grade IV chondral injury compared to non-lax (p=0.026). There was no difference in the proportion of femoral chondral injuries sustained (LAX 13.1% vs. non-lax 26.4%) (p=0.073) but LAX patients had a lower proportion of femoral grade IV chondral injury compared to non-lax (p=0.023). There was no association of chondral injury with trochlear morphology (p=0.843), patellar height (p=0.303), TT-TG (p=0.874), number of instability events (p=0.878), age at time of surgery (p=0.482), and contact vs. non-contact mechanism of injury (p=0.772).Conclusion:LAX patients had a lower proportion of severe patellar and femoral cartilage injuries. There was no significant difference in the proportions of injuries, however there were 2x the proportion of femoral chondral injuries and 1.5x the proportion of patellar chondral injuries in non-lax vs. LAX, which is clinically significant.

Patologia femoro-rotulea: stato dell’arte chirurgico

The patellofemoral pathology is one of the most frequent and disabling musculoskeletal disorders and its high incidence, especially in young and active individuals, involves a considerable socio-economic relevance. The presence of a growing number of the conservative and surgical options is the main indicator of a general lack of consensus about the treatment of this complex pathology. The traumatic injuries, degenerative and structural anomalies could coexist, and the perfect treatment should be aimed to try to correct them as much as possible. Surgical treatment of patellofemoral pain or instability, could act on soft tissues, especially Medial Patello Femoral Ligament (MPFL) reconstruction, or on bone such as Tibial Tubercle Transfer, or trochleoplasty. The treatment of cartilage lesions spans from microfractures to scaffold or prosthetic substitution.

MPFL graft fixation in low degrees of knee flexion minimizes errors made in the femoral location.

To evaluate the appropriate amount of knee flexion in which to secure the graft during medial patellofemoral ligament (MPFL) reconstruction. Heavy suture was used to simulate graft tissue during MPFL reconstruction on eight fresh-frozen cadaveric knees. The sutures were passed through two transverse patellar tunnels and draped over a Kirschner wire at Schöttle's point on the femur. Suture displacement at the location of the wire was measured during knee range of motion from 0 to 135°. The wire's location was then moved to 3 additional locations (1cm proximal, 1cm distal, and 1cm anterior), and the measurements were repeated. Using Schöttle's point, the suture length did not vary throughout all ranges of knee flexion. The distal location resulted in a greater distance between attachment points (i.e. graft tightened) if the measurements began with the knee flexed and then brought into extension. Conversely, with the proximal location, the opposite occurred as the knee was extended (i.e. graft loosened). For all locations other than Schöttle's point, the amount of initial knee flexion for fixation was directly related to the amount of suture length change when the knee was brought into extension. For non-anatomic femoral MPFL graft fixation locations, suture length (and thus graft length) in full extension becomes increasingly altered if the graft is secured in high degrees of knee flexion. Thus, graft fixation in lower degrees of knee flexion is recommended to minimize over or under tensioning the graft when the knee goes into extension if the graft position is placed in a non-anatomic location. To avoid this problem, fluoroscopy should be used to locate the anatomic footprint of the MPFL insertion. While recognizing the limitations of cadaveric research, this study is the first to provide any data to corroborate the widely used practice of securing the MPFL in lower degrees of knee flexion.

The Quantification of Corrosion Damage for Pre-stressed Conditions: A Model Using Stainless Steel

Stainless steel is used extensively within orthopaedics as part of varying surgical procedures such as trochanteric osteotomy, sternum closure, patella tendon repair and reconstruction, patellofemoral ligament reconstruction and internal fracture fixation. This study examines the changes in corrosion behaviour after applying plastic and elastic stresses. Furthermore it analyses how a tensile and a compressive load can affect the corrosion susceptibility of a material. Stainless steel test specimens were divided into three groups of seven to determine how corrosion susceptibility will change when a material is pre-stressed. Potentiodynamic testing was performed to investigate the pitting behaviour of ss304 after being exposed to pre-stressed conditions. All images graded exhibited both area and pit corrosion scores, which significantly differed between the 3 groups (p < 0.001). The samples that were destructively stressed under compression had a mean of 35.5 % corrosion damage (SD 14.5) which is significantly greater (p = 0.001) compared to a mean of 11 % (SD 4.5) corrosion damage present with a material destructively stressed under tension. This study has shown that a material’s corrosion susceptibility changes significantly after being pre-stressed regardless, whether this is mechanically loading it within its yield strength or destructively loading.

Significance of medial patello-femoral ligament in support of patella stability: features of anatomy and biomechanics

The purpose of the study - anatomical and biomechanical substantiation of medial patellofemoral ligament (MPFL) reconstruction in cases of recurrent patella dislocation. Material and methods. Anatomical studies were performed in 27 fresh frozen cadaver knees. Biomechanical study was made using video capture system with 5 specimens of the knee. In the first stage we examined the lateral displacement of the patella when the knee was flexing, and in the second - isometric properties of the MPFL. Results. In all cases MPFL was found between the knee capsule and the superficial fascia. In 6 (22.2%) cases singlebundle structure was revealed, in 14 (51.8%) - two-bundle and in 2 (7.4%) - three-bundle structure. In 2 (7.4%) knee joints MPFL was presented in one thinned bundle, attached to the upper third of the patella. The degree of the MPFL isometry was indicated by changing in the distance between the optical markers located in the regions of attachment of MPFL ligament. For all of the knees this distance had reached 58.3±1.2 mm tibia in knee flexion at 20°; 57.8±,4 mm - when flexed by 30°; 56.9±1,3 mm - at 45°; 56.8±1,3 mm - at 60° of flexion and 53.0±0,7 mm - at 90°. Conclusion. There are several variants of MPFL anatomical structure, and in most cases it has two bundles oriented to the medial surface of the knee from posterior to anterior and from proximal to distal directions. MPFL has a streak of isometry, as a normal characteristic of each anatomical ligament and this isometry must be followed in MPFL reconstruction in case of recurrent patella dislocation.

Low Risk of Physeal Damage from a Medial Patellofemoral Ligament (MPFL) Reconstruction Technique that Uses an Epiphyseal Socket in Children

Objectives:The purpose of this study was to assess short-term distal femoral growth plate safety associated with femoral sockets for hamstring autograft fixation in pediatric MPFL reconstruction.Methods:We retrospectively reviewed a consecutive series of 31 patients (22 females, 9 males) that underwent MPFL reconstruction by one surgeon at a tertiary care academic medical center between 2008 and 2014. Study inclusion criteria consisted of patients who were skeletally immature at the time of surgery, who had greater than 1 year radiographic follow-up and who had a femoral socket introduced during their procedure. Femoral socket location was verified by intraoperative fluoroscopy. All patients received a post-operative x-ray and a clinical follow-up. For the 12 patients that obtained post-operative MRI, growth plate safety was assessed by examining the location of the femoral socket relative to the physis to rule out growth plate injury (Figure 1). Development of lower limb angular deformities or limb length discrepancies was evaluated by examining post-operative standing hip-to-ankle anteroposterior radiographs, patient records, and clinical assessments.Results:The average age at surgery of 13.0 years. The average length of radiographic follow-up was 1.5 years and the average length of clinical follow-up was 1.78 years. At most recent clinical follow-up, 90% (28/31) of patients reported no subsequent patellar dislocations in the treated knee. No patients showed evidence of an angular deformity or limb length discrepancy. Of the 12 patients with postoperative MRI, all showed femoral sockets positioned distal to the physis without growth plate disturbance.Conclusion:The use of an epiphyseal femoral socket for graft fixation presents minimal risk of physeal violation and ensures patellar stability in the majority of pediatric patients. We have demonstrated that using fluoroscopic assistance to place the femoral socket distal to the distal femoral physis is a reliable and safe method for avoiding physeal injury in children with patellar instability.

Medial Patellofemoral Ligament (MPFL) Reconstruction Surgery in Iranian Patients with Recurrent Patellar Dislocation: Report of Three Years Experiences

Medial Patellofemoral Ligament (MPFL) Reconstruction Surgery in Iranian Patients with Recurrent Patellar Dislocation: Report of Three Years Experiences

Revision Surgery in Permanent Patellar Dislocation in DiGeorge Syndrome.

A 29-year-old patient, suffering from DiGeorge syndrome, came to our attention with a history of persistent pain and patellar instability in the left knee after failure of arthroscopic lateral release and Elmslie-Trillat procedure. The patient was unable to walk without crutches and severely limited in daily living activities. Because of arthritic changes of the patellofemoral joint and the failure of previous surgeries it was decided to perform only an open lateral release and medial patellofemoral ligament (MPFL) reconstruction using a biosynthetic ligament in order to obtain patellofemoral stability. At one year post-op range of motion (ROM) was 0–120 with a firm end point at medial patellar mobilization; patella was stable throughout the entire ROM. All the scores improved and she could be able to perform daily activity without sensation of instability. Bilateral patellar subluxation and systemic hyperlaxity are characteristics of syndromic patients and according to literature can be also present in DiGeorge syndrome. MPFL reconstruction with lateral release was demonstrated to be the correct solution in the treatment of patellar instability in this complex case. The choice of an artificial ligament to reconstruct the MPFL was useful in this specific patient with important tissue laxity due to her congenital syndrome.