Patellar Instability In Children Research Articles

PATELLAR HEIGHT IN CHILDREN: ARE THE INDICES USED IN ADULTS APPROPRIATE IN THE PAEDIATRIC POPULATION?

Abnormal patella height has been found to be one of the main reasons for abnormal contact between patella and trochlear groove leading to patellar instability in children. Many methods have been described to diagnose patellar instability but most of them are justified only in adults. The reason being incomplete ossification in the paediatric population. These methods have been divided into direct and indirect methods. We analysed the MRI scan of knee of 57 children between 12–14 years of age with no previous diagnosis of patellar instability. Patients with a diagnosis of patellar instability, previous surgery on the knee or trauma and poor MRI scan were excluded from the study. We used Insall -Salvati Index (ISI), Caton-Deschamp Index (CDI) and Patella-Trochlear Index (PTI) and compared the results. We found that 40% of measurements by CDI and 41% by ISI showed patella alta in patients with normal patella height. 10% of patients in PTI readings had value suggestive of abnormal patella height.We concluded that PTI is a more reliable index to be used in children as it uses the length of articular surface and does not rely on bony landmarks. Studies done show PTI is a more reliable and accurate method of measuring patella height.

Outcomes of surgical treatment of patellar instability in children with Down syndrome

Backgroundpatellar instability is a relatively frequent musculoskeletal disorder in children with Down syndrome (DS). However, such a condition has seldom been studied in the literature, even less its surgical treatment. Different techniques have been offered for this condition; the evidence for surgical options is scarce and primarily based on case reports or case series with few patients and heterogeneous techniques. Given this background, we aimed to evaluate the outcomes of a uniform kind of surgical procedure for such a condition that combined lateral soft tissue release, medial patellofemoral ligament (MPFL) reconstruction (using a partial-thickness quadriceps tendon autograft), the Roux-Goldthwait procedure, and V-Y quadricepsplasty (if needed).Materials and methodsThis retrospective study involved 11 skeletally immature patients (12 knees; 9 males and 2 females), 5.5 to 14.1 years of age, with DS who had patellofemoral instability (PFI) and were managed by this technique between October 2018 and March 2020. Preoperative radiography, CT scan, and MRI were performed to evaluate the physis status, lower limb alignment, patellar height, trochlear morphology, and any associated knee pathology. A functional knee assessment was done by using the Kujala score and the modified Lysholm score.ResultsThe mean time of follow-up (± SD) was 47.7 ± 5.8 months (range: 39–56). Pre-operatively, the Kujala score (± SD) was 52.6 ± 14.3 (range: (31–74), and at final follow-up, it was 92.2 ± 4.4 (range: (88–98), showing a significant improvement (P < 0.001). The preoperative modified Lysholm score (± SD) was 54.3 ± 8.1 (range: 39–62), and at final follow-up it was 92.4 ± 5.3 (range: 82–96), showing a significant improvement (P < 0.001). All patients had a stable patella without a recurrence of instability and regained full ROM. There was no incidence of a patellar fracture or femoral physis injury.ConclusionsOur proposed technique of combined soft tissue procedures, including lateral soft tissue release, MPFL reconstruction (using a partial-thickness quadriceps tendon autograft), the Roux-Goldthwait procedure, and V-Y quadricepsplasty, was an effective method for treating patellar instability in children with DS while avoiding physeal injury and patellar fracture. Functional scores and radiological outcomes were improved.Level of evidenceIV; retrospective case series.

Indications of Arthroscopy in the Treatment of Patellar Instability in Children.

Purpose Understanding the relevant risk factors for patellar instability and the clinical and radiographic testsnecessary to determine optimal treatment. This case series intends to evaluate arthroscopic indications in the treatment of patellar instability in children. Methods From 2013 to 2021, 33 patients (seven to 16 years of age) with 35 knees sustaining first-time dislocation with loose bodies, recurrent dislocation or subluxation, and habitual dislocation were arthroscopically operated on according to the flow chart. Periods of follow-up were two to 10 years (avg. 5.5 years). Follow-up assessment included the recurrence, complications (joint stiffness and excessive reduction), and the final function outcomes by using the Kujala score. Results Among 35 knees, there were two (5.7%) first dislocations, 30 (85.7%) recurrent dislocations, and three (8.6%) habitual dislocations, lateral release 27/35 (77.1%), medial reefing 23/35 (65.7%), reconstruction of the medial patellofemoral ligament(MPFL) 12/35 (34.3%). The major complication was a knee of extensive stiffness after medial reefing and lateral release. Recurrence was in 4/35 (11.4%) of knees, not correlated to lateral release (p=0.21), medial reefing, or reconstruction of MPFL (p=0.07); in about 23 knees of medial reefing, recurrence was significantly correlated to number of knots (p=0.045). The final functional results according to Kujala were 88-100 (avg. 95.5). Conclusions This study showed the role of arthroscopy in both medial reefing and reconstruction of MPFL in children by low recurrence rate and high Kujala score at final follow-up. There was no significant correlation between recurrence and the procedures as arthroscopic indications counted on the flow chart.

Current practice trends in the surgical management of patellofemoral instability: a survey of the Paediatric Research in Sports Medicine (PRiSM) Society.

PurposePatellofemoral instability (PFI) in young athletes presents both diagnostic and management dilemmas for which consensus often does not exist. The purpose of this study was to identify trends in management of PFI in children and adolescents in the United States and nationwide.MethodsA 27-question multiple choice survey was distributed in 2018 to the members of the Pediatric Research in Sports Medicine (PRiSM) Society regarding treatment of PFI in paediatric and adolescent patients.ResultsIn all, 56 of the respondents who were orthopaedic surgeons that manage patellar instability in children and adolescents and had performed PFI surgery more than five times in the past year completed the entire survey. A total of 41% of respondents reported that surgery for fragment refixation or loose body removal was indicated when a loose body or osteochondral fragment was evident, regardless of fragment size. Overall, 74% reported that if surgery was performed for an osteochondral loose body, primary repair (36%) or reconstruction (38%) of medial patellofemoral ligament (MPFL) was also completed. A total of 89% of members reported MPFL reconstruction in the absence of alignment or rotational abnormalities, tibial tubercle lateralization or trochlear dysplasia in skeletally immature patients; 59% reported performing the MPFL reconstruction with hamstring allograft, while 30% prefer autograft (hamstring, quadriceps). For patients with significant trochlear dysplasia, 87% reported no surgical management of trochlea in first-time or in revision surgery.ConclusionThere is a lack of consensus regarding optimal diagnostic and treatment algorithms in the management of PFI, however, consistent trends have emerged among paediatric sports medicine surgeons.Level of EvidenceLevel V – survey of expert opinion and experience

A National Perspective of Patellar Instability in Children and Adolescents in the United States: MPFL Reconstruction Is Three Times Higher Than the Incidence of Isolated Lateral Release

The objective was to (1) evaluate any recent changes in the United States in the incidences of medial patellofemoral ligament (MPFL) reconstruction and isolated lateral release for patellar instability in children and adolescents, (2) identify concomitant procedures with MPFL, and (3) report national complication rates after MPFL reconstruction with and without concomitant procedures in children and adolescents. A national database was queried for patients aged 5 to 18 years who underwent operative treatment for patellar instability from 2010 to 2018. Inclusion criteria were either an MPFL reconstruction or lateral release for a diagnosis of patellar instability. Concomitant procedures with MPFL reconstruction assessed were tibial tubercle osteotomy, associated arthroscopic procedures, and lateral release. Changes in incidence in MPFL reconstruction, lateral release and concomitant procedures were assessed. The following postoperative complications were assessed: knee stiffness, infection, patella fracture, and growth arrest or angular deformity. 2,161 patients who underwent MPFL reconstruction and 1,159 patients who underwent isolated lateral release for patellar instability were identified. The incidence of MPFL reconstruction in adolescents from 2010 to 2018 did not change significantly (2010: 7.11, 2018: 5.91, P= .137), while isolated lateral release decreased (2010: 6.06, 2018: 1.83, P < .0001). Concomitant procedures with MPFL reconstruction were common, with arthroscopy being the most frequent (58-67%). The most common complication within 90 days of surgery was patella fracture (0.4% to 2.0%). Infection (0.4% to 1.0%) and growth arrest (0.09% to 0.61%) were the least common. MPFL and arthroscopy had a decreased risk of growth arrest following surgery compared to MPFL alone (P= .038). The incidence of MPFL reconstruction remained high from 2010 to 2018, while isolated lateral release decreased during the same time period. Complications after MPFL reconstruction, isolated lateral release, and concomitant procedures were infrequent, with postoperative patella fracture the most common. IV, case series.

Risk factors for recurrent patellar instability in children and adolescents

Purpose: Acute patellar dislocation is the most common traumatic injury about the knee in younger active patients and challenging to treat. Recurrence rates are high and carry a substantial risk of irreparable cartilage damage and future patellofemoral arthritis. The goals of this study were to describe factors associated with ipsilateral recurrent patellar instability in adolescent patients after first-time patellar dislocation. Methods: The study included a cohort of 110 adolescent patients, 122 knees, who experienced a first-time patellar dislocation between 2007 and 2016. Information related to …

Risk factors for recurrent patellar instability in children and adolescents

Risk factors for recurrent patellar instability in children and adolescents

Patellar dislocation in children and adolescents : Current developments in diagnostics and treatment

The latest results concerning patellar instability in children and adolescents lead to abetter understanding of the underlying pathology. Determination of necessary diagnostic procedures and treatment of patellar instability in children and adolescents. Analysis of available literature based on asystematic MEDLINE analysis. Diagnostics, risk factors und treatment of adult patellar instability are applicable in the treatment of children. Atrend towards early surgical stabilization after primary dislocation was identified. Growth plate-preserving methods for autologous MPFL reconstruction can safely be used in children. For children with a high risk of redislocation, primary surgical intervention should be performed. The necessary method must be determined by individual risk factor analysis.

Modified Roux-Goldthwait Procedure for Management of Patellar Dislocation in Skeletally Immature Patients with Down Syndrome.

Background:Patellar instability is a common problem in Down syndrome patients since their childhood. Several treatment have been proposed, but relapses are frequent and not all surgeries are suitable for growing patients. The aim of the present study is to evaluate the clinical and radiographic outcomes of a modified Roux-Goldthwait technique, for the management of patellar instability in children with Down syndrome at minimum 5-year followup.Materials and Methods:19 patients (23 knees) affected by Down syndrome surgically treated for patellar dislocation, between 2000 and 2012 were included in this study. The mean age of patients was 9.5 years (range 3.7 – 15 years) and had a Dugdale Grade III, IV, and V patellar dislocation. Trochlear groove dysplasia was present in 15 patients. Each patient was clinically evaluated considering relapse rate, pre- and postoperative range of motion (ROM), Kujala score, and modified Lysholm score. Radiographic examination was performed on standard X-ray considering patellar height, trochlear angle, and patellofemoral congruence angle.Results:The mean followup was 134 months (range 62–206 months). No case of relapse of dislocation was registered with an improved ROM (significant for knee extension, P < 0.05). The Kujala score showed significant improvement from a mean preoperative value of 39 ± 6.3 to a mean postoperative value of 92.7 ± 3.4 (P < 0.05) at final followup such as the modified Lysholm score (from mean preoperative 55.6 ± 6.3 to mean postoperative of 94.2 ± 2.6). Radiographs performed at latest followup showed a tendency to normalization of all the parameters considered, with a restored patellofemoral congruence and trochlear groove shape and without signs of osteoarthritis.Conclusion:The present study showed that the Roux-Goldthwait procedure is a valid surgical option for the treatment of patellar dislocation in children with Down syndrome.

Combined Reconstruction of the Medial Patellofemoral Ligament (MPFL) and Medial Quadriceps Tendon-Femoral Ligament (MQTFL) for Patellar Instability in Children and Adolescents: Surgical Technique and Outcomes.

A variety of surgical options exist to treat the challenging problem of recurrent patellar instability in children and adolescents. The goal of the current study is to describe a novel combined reconstruction technique of both the medial patellofemoral ligament (MPFL) and the medial quadriceps tendon-femoral ligament (MQTFL) and report patient outcomes of a single-surgeon series. All patients studied underwent simultaneous MPFL and MQTFL reconstruction for patellar instability using gracilis allograft. Demographic, clinical, and radiographic data were collected. Subjective outcomes were assessed for a minimum of 1 year postoperatively. Twenty-five patients (27 knees), including 15 female and 10 male individuals with an average age of 15.0±2.2 years (range, 10.3 to 18.9), were included. Prior ipsilateral patellofemoral surgery had been performed in 6 of 25 (24%) patients. Simultaneous hemiepiphysiodesis for valgus deformity at the time of combined reconstruction was performed in 5 of 25 (20%) patients. Preoperative imaging showed a mean tibial tubercle-trochlear groove of 17.2±3.8, Caton-Deschamps Index (CDI) of 1.13±0.16, and trochlear dysplasia Dejour A/B [22/26 (85%)] or Dejour C/D [4/26 (15%)]. A total of 18 patients (19 knees, 72%) returned outcomes questionnaires at a mean 2.0±0.5 years after surgery. Mean Kujala, Pedi-IKDC, and Lysholm scores were 85.9±13.9, 81.5±15.2, and 84.3±13.5, respectively. Later revision procedure (tibial tubercle osteotomy) for recurrent patellar instability was required in 2 of 25 patients (8%) patients, and another patient reported persistent instability not requiring revision. Return to sports was possible in 10 of 13 self-reported athletes (77%) at a mean of 5.8±3.9 months (range, 2 to 15). The present study describes a combined MPFL-MQTFL reconstruction technique with favorable short-term results. Although particularly useful in the skeletally immature patient where tibial tubercle osteotomy should be avoided and patellar fixation minimized, combined reconstruction may potentially be appropriate for older patients with patellofemoral instability as well. This technique more closely recreates the native anatomy of both the MPFL and MQTFL, may decrease the risk of patellar fracture, and can be useful in the revision setting. Level IV.

Current methods of patellar instability imaging in children. Selection of the best treatment approach

Background. Patellar instability is a common problem in pediatric patients. Up to 2%–3% of all knee injuries are associated with acute patellar dislocation. According to the data in the literature, patients aged 10–17 years are at the highest risk of patellar dislocation and subsequent instability. These patients must be evaluated according to the proposed algorithm to select the optimal treatment method.&#x0D; Aim. To diagnose patellar instability in children and subsequently select the optimal treatment method based on acquired data.&#x0D; Materials and methods. The study is based on data acquired through the examination and treatment of 147 patients at the 9th Department of Pediatric Traumatology and Orthopedics. Great emphasis was put on computed tomography (CT) data, its essential parameters, which require the most thorough analysis, and assessment methods. These parameters include patellar tilt, dysplasia of the distal metaepiphysis of the femur, the tibial tubercle–trochlear groove index, and the rotational relation of the femur and tibia.&#x0D; Results. A novel algorithm for patient examination using CT is proposed. Data obtained by multislice CT (MSCT) had a significant influence on the selection of the surgical method for treating patients with patellar instability.&#x0D; Conclusion. The examination of patients with patellar instability using MSCT in adherence to the proposed diagnostic algorithm allows the selection of the optimal treatment method, which will increase the likelihood of rapid recovery of patients and their return to the level of activity similar to that before injury.

Special Considerations for Pediatric Patellar Instability.

Patellar instability in children and adolescents is a challenging subset to treat. Varied forms of instability, ranging from episodic dislocation to fixed dislocation, have been recognized. It is of utmost importance for the treating physician to recognize these different patterns of instability and their associated risk factors, as more complex patterns of instability would require more extensive surgical procedures. Medial patellofemoral ligament (MPFL) reconstruction, by itself, may not suffice or may not be appropriate for the more complex instability patterns. Appropriate and early treatment of such instability in children would allow for functional progression and possible remodeling of the trochlea. However, early treatment has the associated risk of growth disturbances when surgical procedures are performed around open physis or if adult-type bony procedures are performed in children. Recent knowledge about the relationship between trochlea, MPFL femoral attachment, and distal femoral physis could help to advance safe surgical care for these patients. This article reviews the pathophysiology, risk factors, and the existing classification systems for patellar instability in children and adolescents. It focuses on varied surgical techniques, which are unique to the pediatric population, and summarizes the outcomes of these surgical techniques.

Surgical Treatment of Patellar Instability in Children and Adolescents

Surgical Treatment of Patellar Instability in Children and Adolescents

Predictors of Recurrent Patellar Instability in Children and Adolescents After First-time Dislocation.

Patellar dislocations are one of the most common knee injuries in children and adolescents and are challenging to treat. Recurrence rates are relatively high and many patients have functional limitations, even in the absence of a recurrent instability episode. The purpose of this study was to examine the risk factors in patients with first-time patellofemoral dislocations to develop a prediction model of recurrence. A single institution retrospective review of all patients with a first-time patellofemoral dislocation from 2002 to 2013 was performed. Demographic risk factors (age, sex, laterality, mechanism of injury, and history of contralateral patellar dislocation) and radiographic risk factors (increased patella height, trochlear dysplasia, and skeletal immaturity) were examined. Patella height was measured using Caton-Deschamps index (CDI). Trochlear dysplasia was assessed using the 2-grade Dejour classification and skeletal immaturity was assessed based on the distal femur and proximal tibia physis (open, closing, or closed). In total, 266 knees in 250 patients were included in the study. Of these, 222 (83.5%) were treated nonoperatively and 44 (16.5%) were treated surgically. Of the knees treated nonoperatively, 77 (34.7%) had a recurrence. Significant risk factors for recurrence on univariate analysis were age 14 years and below, history of contralateral patellar dislocation, trochlear dysplasia, skeletal immaturity, and a CDI>1.45. Multivariate analysis was performed and trochlear dysplasia and skeletal immaturity were the most significant factors with odds ratios of 3.56 and 2.23, respectively. The presence of all 4 multivariate risk factors (CDI>1.45, history of contralateral patellar dislocation, trochlear dysplasia, and skeletal immaturity) had a predicted risk of recurrence of 88%. The presence of any 3 risk factors had a predicted risk of about 75% and the presence of any 2 risk factors had a predicted risk of about 55%. Trochlear dysplasia, skeletal immaturity, CDI>1.45, and a history of contralateral patellar dislocation were all significant risk factors for recurrence in patients with first-time patellar dislocations. A predictive model for calculation of recurrence risk was developed for any combination of the different risk factors. This information is useful when counseling patients and their families after first-time patellar dislocation about prognosis and potential outcomes. Level IV-retrospective case series.

Combined Reconstruction of the Medial Patellofemoral Ligament (MPFL) and Medial Quadriceps Tendon - Femoral Ligament (MQTFL) for Patellar Instability in Children and Adolescents: Surgical Technique and Outcomes

Objectives:A variety of surgical options exist to treat the challenging problem of recurrent patellar instability in skeletally immature patients. The current study describes a combined reconstruction technique involving both the medial patellofemoral ligament (MPFL) and the medial quadriceps tendon - femoral ligament (MQTFL) and reports patient outcomes of a single-surgeon series.Methods:All patients studied underwent combined MPFL and MQTFL reconstruction for patellar instability. Demographic data, pre- and post-operative radiographic data were collected. Reconstruction was performed using gracilis allograft. The graft midportion was fixed to the MPFL insertion on the femur via suture anchor. One arm of the graft (MPFL) was tunneled under medial retinaculum to the medial border of the patella and fixed there via suture anchor, while the other (MQTFL) arm was tunneled, delivered under the VMO and brought through the medial distal quadriceps tendon and sutured in place. Subjective outcome scores (Kujala, Pedi-IKDC, Lysholm) were collected via questionnaires mailed to patients more than one year from surgery.Results:A total of 25 patients (27 knees), including 15 females and 10 males with an average age of 15.0 ± 2.2 years (range 10.3-18.9), underwent combined MPFL and MQTFL reconstruction. 6/25 (24%) had undergone prior ipsilateral patellofemoral surgery for instability. 5/25 (20%) underwent simultaneous guided growth via hemiepiphysiodesis for valgus deformity at the time of combined reconstruction. Preoperative imaging showed a mean TT-TG of 17.2 ± 3.8, Caton-Deschamps Index (CDI) of 1.13 ± 0.16, and trochlear dysplasia Dejour A/B (22/26 (85%)) or Dejour C/D (4/26 (15%)). A total of 18 patients (19 knees, 72%) returned outcomes questionnaires at a mean 2.0 ± 0.5 years after surgery. Mean Kujala, Pedi-IKDC, and Lysholm scores were 85.9 ± 13.9, 81.5 ± 15.2, and 84.3 ± 13.5, respectively. 2/25 patients (8%) later required a revision procedure (tibial tubercle osteotomy) for recurrent patellar instability, and another patient reported persistent instability not requiring revision. 10/13 patients (77%) were able to return to sports at a mean of 5.8 +/- 3.9 months (range 2-15).Conclusion:The current study describes a novel anatomically-validated surgical technique involving the simultaneous reconstruction of both the MPFL and MQTFL in a pediatric patient population. Follow-up data presented demonstrates overall positive results in treating this challenging problem in a young patient population.

Anatomic reconstruction of the medial patellofemoral ligament in children and adolescents using a pedicled quadriceps tendon graft shows favourable results at a minimum of 2-year follow-up

In adults, reconstruction of the medial patellofemoral ligament (MPFL) has shown good results. Treatment for recurrent patellar instability in children and adolescents with open growth plates, however, requires alternative MPFL reconstruction techniques. This study presents the outcomes of a minimally invasive technique for anatomic reconstruction of the MPFL in children using a pedicled superficial quadriceps tendon graft, hardware-free patellar graft attachment, and anatomic femoral fixation that spares the distal femoral physis. Twenty-five consecutive patients with patellofemoral instability and open growth plates underwent anatomic reconstruction of the MPFL using a pedicled superficial quadriceps tendon graft. Preoperative radiographic examination included AP and lateral views to assess patella alta and limb alignment. Magnetic resonance imaging was performed to evaluate trochlear dysplasia and tibial tubercle-trochlear groove distance. Evaluation included pre- and post-operative physical examination, Kujala score, visual analog scale (VAS), and Tegner activity score. The average age at the time of operation was 12.8years (9.5-14.7). The average follow-up after operation was 2.6years (2.0-3.4). No recurrent dislocation occurred. Twenty patients were very satisfied (80%), four patients were satisfied (16%), and one patient was partially satisfied with the surgical procedure (4%). No patient was dissatisfied. The median Kujala score significantly improved from 63 (44-81) preoperatively to 89 (77-100) post-operatively (P<0.01), and the median VAS score improved significantly from 4 (1-7) to 1 (0-4) (P<0.01). The Tegner activity score increased, but not significantly, from 4 (3-8) preoperatively to 5 (3-8) post-operatively (non-significant). The described technique for MPFL reconstruction with a pedicled quadriceps tendon is a safe and effective technique with good clinical results and allows patients to return to sports without redislocation of the patella. It might therefore be a valuable alternative to more extensive procedures in paediatric and adolescent patients. Prospective study, Level III.

Treatment of patellar instability in children and adolescents with cerebral palsy

Treatment of patellar instability in children and adolescents with cerebral palsy

Predictors of Recurrent Patellar Instability in Children and Adolescents following First-Time Dislocation

Predictors of Recurrent Patellar Instability in Children and Adolescents following First-Time Dislocation

"Modified Adductor Sling Technique"- a surgical therapy for patellar instability in children and adolescents

Aims and Objectives:Due to open femoral physis, the therapy of patellar instability in children and adolescents is challenging. We developed a surgical technique, modified form of the "Adductor-Sling-Technique" by Sillanpää which offers a surgical treatment to avoid damage to the femoral physis. The purpose of this study is to determine whether there is a benefit in the clinical outcome for patients operated by the "modified Adductor Sling Technique" in comparison to patients with other surgical procedures.Materials and Methods:Twenty "modified Adductor Sling" reconstructions in 19 patients (age 11-24) were included in the study until now, 15 patients with open physis and 4 patients with closed physis with special indications. Since 2010 "modified Adductor Sling" reconstruction was performed by looping the gracilis tendon around the adductor magnus tendon and attaching it at the medial facette of the patella. Clinical outcome was retrospectively evaluated at a mean follow-up period of 1.3 years (range 0.5-3.6). The evaluation also included Lysholm Score, Kujala Score and DGU score. Statistical analysis was performed using IBM®SPSS®Statistics Version 21. A P value less than 0.5 was considered significant.Results:The average age at the time of operation was 14.9 years (range 11.2-24.3). Recurrent dislocation occurred in 4 out of 20 cases (20%). It was noticeable that out of those 4 patients 2 patients had a lateral release in addition to the "modified Adductor Sling Technique" due to lateral hyperpression. No other patients had a lateral release in our patient population. Also, out of those 4 patients 3 patients had an additional maltracking of the patella, caused by a high TTTG, severe trochlea dysplasia or additional axial deformity. The overall Kujala Score was 87 (range 46-100) points, in patients without re-dislocation it was 94 (range 46-100) points. The overall Lysholm Score was 85 (range 39-100) points, in the group without re-dislocation 90 (range 39-100) points. The mean TTTG was 16,59 (range 11,7-21,4) mm, in the group without re-dislocation it was 16,24 (range 11,7-21,4) mm. There was no significant difference between the patients with or without re-dislocation(p=0,312).Conclusion:The "modified Adductor Sling Technique" offers relevant clinical improvements in knee function and pain. An advantage is the avoidance of damaging the femoral physis. Our Hypothesis of less recurrent dislocation rates could not be confirmed. The re-dislocation rate was even higher than in MPFL reconstruction using femoral fixation in adults. Patients with patellar instabilities without maltracking (no severe trochlea dysplasia, no axial deformity, moderately elevated TTTG) and open physis benefit from the "modified Adductor Sling Technique". This technique is not recommended in patients with patellar instability and additional maltracking.

Patellar instability in children and adolescents

Patellar instability is a common occurrence in the skeletally immature patient population, and multiple treatment options exist. Nonoperative treatment is appropriate for patients without osteochondral injuries and includes bracing and physical therapy focusing on strengthening of the gluteals as well as the vastus medialis obliquus muscles. Risk factors for recurrent instability include patella alta, trochlear dysplasia, and age younger than 25 yr. Isolated reconstruction of the medial patellofemoral ligament is indicated in patients with recurrent instability with normal tibial tubercle-trochlear groove distances with or without trochlear dysplasia. Distal realignment procedures risk physeal injury and are thus not routinely used in the skeletally immature population. Long-term data on the effect that trochleoplasty has on chondral surface have not been established and it has thus been a procedure reserved primarily for skeletally mature patient populations with chronic patellar instability. Despite multiple operative treatment methods, knee pain, decreased knee flexion, and recurrent instability are the most common postoperative complications.