Treatment Of Patellar Instability Research Articles

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.

Poster 276: Assessment of Trochlear Cartilage Thickness and Volume Using Sagittal Magnetic Resonance Images to Quantify Trochlear Dysplasia: A Matched-Cohort Study

Objectives: Trochlear dysplasia is considered a major contributing factor for patellar instability. More recently, trochleoplasty procedures have become popularized to address this morphological abnormality. Both thick and thin flap trochleoplasty techniques exist, with the goal to deepen the trochlea while avoiding perforation of the trochlear cartilage during the procedure. However, the relative cartilage thickness in the dysplastic trochlea has not been well described. This study aimed to assess trochlear cartilage thickness and volume in knees with and without patellar instability and the relationship to measurements of trochlear dysplasia. Methods: 25 knees with symptomatic patellar instability were compared with 25 gender-matched knees. Retrospective chart review was performed to obtain demographic data. On sagittal images, trochlear cartilage thickness (TCT) and trochlear cartilage volume (TCV) were analyzed at the center, medial border, and lateral border of the trochlea. TCT was defined as the cartilage thickness halfway along the trochlear length at its maximum dimension. TCV was defined by total area of cartilage proximal to the plane of the intercondylar midpoint. Symptomatic and control values were compared using paired sample t-test. Stepwise multivariate linear regression was performed to assess for associations with standard radiographic parameters of trochlear dysplasia. Results: TCT was significantly different between the medial, central and lateral trochlea in both the symptomatic and control groups (p<0.001). Only lateral TCT demonstrated a significant difference between groups, which was 20.3% (p=0.035) thicker in the symptomatic cohort compared to controls. No significant differences existed in TCV between symptomatic and control groups. In females, central TCT was 28.3% thicker in the symptomatic cohort (p=0.024), while medial TCV was 2.3x greater (p = 0.019). Males failed to demonstrate gender specific differences. Regression analysis demonstrated that patient height showed a significant relationship with all measurements except for medial TCV. Central TCT demonstrated a significant, independent relationship with trochlear depth (Coefficient 0.38, p = 0.011), while central TCV demonstrated a significant, independent relationship with trochlear depth (Coefficient 9.9, p <0.001), sulcus angle (Coefficient 1.1, p <0.001), and lateral trochlear inclination (Coefficient -1.1, p <0.001). Conclusions: While trochlear dysplasia typically refers to abnormal bony morphology, this study demonstrates the role of differential contributions of chondral thickness and volume between knees with and without patellar instability, and that these measurements correlated with severity of dysplasia. Future studies should further investigate the relationship between TCT and TCV with other dysplasia parameters to better inform the surgical considerations of performing trochleoplasty in the treatment of patellar instability. [Table: see text]

Current Concepts in Diagnostics and Treatment of Patellar Instability: Review

Background. Patellar instability is one of the most common pathologies of the musculoskeletal system, predominantly observed in physically active young individuals. It ranks third in the structure of knee joint injuries after anterior cruciate ligament and meniscal injuries.
 The aim of this review to present modern perspectives on the diagnosis, principles, and surgical treatment techniques for patients with patellar instability based on an analysis of the literature.
 Methods. Publications were searched in the PubMed/MedLine and eLIBRARY databases. A total of 112 foreign articles published between 1984 and 2023 and 12 domestic publications from 2011 to 2022 were found. During the analysis, 68 articles were selected, which had full texts or abstracts containing sufficient information on diagnostic methods, commonly used standard and modified surgical correction methods for patellar instability, and treatment protocols considering patient age structure, instability characteristics, and functional demands.
 Results. A qualitatively new stage in the reconstructive and restorative surgery of patellar instability is the in-depth examination of patients to determine the extent of damage to the medial retinaculum and the presence of dysplastic changes in anatomical structures that provide normal biomechanics of the knee extensor apparatus. A strictly individual approach to the selection of surgical treatment methods considering risk factors contributing to the development of chronic patellar instability becomes of particular importance.
 Conclusion. Precise restoration of the medial patellofemoral ligament, supplemented by the correction of identified dysplastic changes in anatomical formations of the knee joint area, allows for better functional outcomes in patients with acute and chronic patellar instability.

Surgical versus conservative management of patellar re-dislocation: clinical and radiological results at a mid-term follow-up of 5 years

Background: Patellar dislocation accounts for 2–3% of all knee lesions and is the second most common cause of traumatic hemarthrosis of the knee. Proper treatment is essential to minimize long term sequelae, such as recurrent dislocation, painful subluxation, and osteoarthritis. Aim: The purposes of this perspective randomized study were: 1) to evaluate the mid-term clinical and radiological results of the Elmslie–Trillat procedure for the treatment of traumatic patellar re-dislocation; and 2) to compare the results, especially radiological osteoarthritis development, with those of non-operative management for traumatic patellar re-dislocation. Methods: From June 2013 to February 2015, 65 patients were admitted to our Emergency Department for a first patellar dislocation episode. All patients were treated non-operatively. When a second episode occurred within two years, patients were randomly assigned in two groups: Group A, patients treated surgically with Elmslie-Trillat procedure, and Group B, patients were further treated non-operatively. The Knee Society Score (KSS), Lysholm scale and Kujala questionnaire were administered immediately after the re-dislocation and at the final follow-up. Tangential patella radiographs were evaluated for patellofemoral osteoarthritis and graded according to Sperner’s classification. Results: The mean follow-up was 6.4±1.7 years (range 5-8) in Group A and 6.3±2.1 years (range 5-9) in Group B. In Group A, the KSS and Lysholm scale showed significant differences between pre- and post-operatively values (p<0.05). The mean Kujala score was significantly lower in Group B when compared with the mean value of Group A (p<0.05). At the final follow-up of more than 5 five years, the mean grade of patellofemoral osteoarthritis according to Sperner’s classification changed in Group A and Group B, with respectively 25% and 29% of patients having a grade greater than or equal to 3. Conclusion: This study confirms that Elmslie-Trillat is a safe and effective procedure in the treatment of patellar instability, relieving pain and inability, and reducing recurrence risk. However, it cannot avoid the degenerative changes occurring in the natural evolution of patellar dislocation.

Poster 228: Comparison of Isometric Properties Between the Medial Patellofemoral Complex Fibers

Objectives:The medial patellofemoral complex (MPFC) has a broad attachment on the patella and quadriceps tendon. Recent anatomic studies have demonstrated a corresponding elongated footprint on the medial femur in which the proximal fibers constitute the MQTFL and the distal fibers form the MPFL. Reconstruction of the MPFL and MQTFL have traditionally been described using the midpoint of the femoral footprint (Schottle’s point) while varying the graft’s position on the patella or quadriceps tendon. The purpose of this study was to compare graft isometry of MPFL, MQTFL, and MPFC reconstruction when using a standard femoral tunnel versus the corresponding anatomic femoral tunnel, and to identify the morphologic risk factors that influence each reconstruction technique.Methods:3D digital knee models were created from dynamic CT images of asymptomatic knees of patients with contralateral patellar instability. Knee models were grouped into 10° intervals and graft length, or distance between the defined points on the femur and extensor mechanism were measured in the following conditions: 1) standard MQTFL (sMQTFL), between the midpoint of the femoral footprint and the quadriceps tendon attachment, 2) anatomic MQTFL (aMQTFL), between the proximal femoral footprint and quadriceps tendon attachment, 3) standard MPFL (sMPFL), between the femoral footprint midpoint and the patellar attachment, 4) anatomic MPFL (aMPFL), between the distal femoral footprint and patellar attachment, and 5) MPFC, between the midpoints of the femoral and quadriceps tendon/patellar attachments. Changes in graft length between 0°and 40° flexion were compared for each reconstruction technique and assessed for their relationship to morphologic risk factors using stepwise multiple regression analyses.Results:12 knees were included in this study (3M, 9F; mean age 23.1+/-8.0y). Mean graft length was significantly greater at 0° than 40° in all reconstructive techniques (p<0.001 to p=0.045). Graft length changes showed no significant differences between reconstructive techniques when using corresponding anatomic femoral tunnels (aMQTFL, aMPFL, aMPFC). When compared to aMPFC (8.8mm), graft length changes were greater in sMQTFL (11.3, p=0.005) and smaller in sMPFL (6.9, p=0.037); however 2/12 (16.7%) of the sMPFL had unfavorable length change patterns that were tighter in flexion than extension. Overall, proximal reconstructions (aMQTFL and sMQTFL) were the most sensitive to the presence of morphologic risk factors (R=.933, R2=0.87 and R=0.898,R2=0.81, respectively) with patella alta having the greatest effect. In contrast, the distal reconstructions (aMPFL and sMPFL) did not have a significant relationship with risk factors but trended toward a significant relationship with TTTG distance (p=0.072 and 0.064, respectively).Conclusions:For MQTFL and MPFL reconstructions, using the corresponding anatomic femoral attachment showed more favorable length change patterns over using the currently described standard femoral tunnel. Overall, graft length changes in proximal (quadriceps tendon) reconstructions were more sensitive to the presence of patella alta, while distal (patellar) reconstructions were influenced by TTTG distance. Further studies are needed to identify the optimal reconstructive technique based on each patient-specific morphologic patterns in the treatment of patellar instability.

Poster 111: Poor Inter-observer Reliability of TT-TG Measurement Among Orthopaedic Sports Medicine Surgeons Regardless of Measurement Technique

Objectives:Tibial tubercle-trochlear groove distance (TT-TG) is an important radiologic parameter in the diagnosis and treatment of patellar instability. However, there is substantial heterogeneity in the literature regarding the most appropriate measurement protocol for assessing TT-TG distance. The objective of this study was to evaluate the inter- and intra-observer reliability of TT-TG distance measurement in healthy knees performed by fellowship-trained orthopaedic sports medicine surgeons.Methods:A convenience sample of 29 magnetic resonance imaging scans (MRIs) of the knee was assembled after screening to ensure there was no ligamentous rupture, meniscal pathology, cartilage injury, subchondral edema, or abnormal masses in the bone or muscle. An a priori power analysis determined that this number of MRIs would provide greater than 90% power to detect a statistically significant difference in intraclass correlation of 0.95 (a < 0.05). Three fellowship-trained orthopaedic sports medicine surgeons read the MRIs and recorded the TT-TG distance using their method of choice. After a minimum of 5 months, the MRIs were read again, this time using a standardized evidence-based method to measure the TT-TG distance. Kappa statistics were calculated to evaluate inter- and intra-observer reliability.Results:Among the initial TT-TG distance measurements, kappa was equal to -0.006 (P = 0.690) when assessing inter-observer reliability. Introduction of the standardized measurement protocol was associated with no significant change in inter-observer reliability (kappa = 0.124, P = 0.070). The individual TT slice that was selected for TT-TG distance measurement demonstrated a kappa statistic of 0.192 (P < 0.001) for the surgeons’ method of choice and a kappa statistic of 0.037 (P = 0.455) for the standardized method. Similarly, TG slice selection using the surgeons’ method of choice yielded a kappa statistic of -0.005 (P = 0.949) and a kappa statistic of -0.102 (P = 0.140) for the standardized method.Conclusions:Our findings demonstrate poor inter-observer reliability of TT-TG distance measurement in healthy knees that was not improved with the application of a standardized evidence-based measurement protocol. TT and TG slices selected by surgeons varied widely. Future research should focus on comparing TT-TG distance measurements across a wider variety of knees (ranging from healthy to those with patellar instability), as this may improve the inter-observer reliability of TT-TG measurement.Table I.Variation in TT-TG Distance Measurement and MRI Slice Selection Between Surgeons

Blood flow Restriction training After patellar INStability (BRAINS Trial)

BackgroundPatellar instability is a common and understudied condition that disproportionally affects athletes and military personnel. The rate of post-traumatic osteoarthritis that develops following a patellar dislocation can be up to 50% of individuals 5–15 years after injury. Conservative treatment is the standard of care for patellar instability however, there are no evidence-informed rehabilitation guidelines in the scientific literature. The purpose of this study is to assess the effectiveness of blood-flow restriction training (BFRT) for patellar instability. Our hypotheses are that this strategy will improve patient-reported outcomes and accelerate restoration of symmetric strength and knee biomechanics necessary to safely return to activity.Methods/designThis is a parallel-group, superiority, randomized, double-blinded, placebo-controlled clinical trial at the University of Kentucky, sports medicine clinic that aims to recruit 78 patients with acute patellar dislocations randomly allocated into two groups: (1) sham BFRT and (2) BFRT. Both groups will receive the current standard of care physical therapy 3 times per week for up to 9 weeks. Physical therapy sessions will consist of typical standard of care treatment followed by BFRT or sham BFRT. Primary outcomes include the Norwich Patellar Instability Scale, quadriceps strength, and imaging and biochemical biomarkers of cartilage degradation.DiscussionThe current standard of care for non-operative treatment of patellar instability is highly variable does not adequately address the mechanisms necessary to restore lower extremity function and protect the long-term health of articular cartilage following injury. This proposed novel intervention strategy uses an easily implementable therapy to evaluate if BFRT significantly improves patient-reported outcomes, function, and joint health over the first year of recovery.Trial registrationBlood Flow Restriction Training, Aspiration, and Intraarticular Normal Saline (BRAINS) NCT04554212. Registered on 18 September 2020.

Adding a tibial tubercle osteotomy with anteromedialisation to medial patellofemoral ligament reconstruction does not impact patient-reported outcomes in the treatment of patellar instability

ObjectivesAn isolated medial patellofemoral ligament (MPFL) reconstruction (MPFLR) has been demonstrated to be an effective treatment option in the prevention of patellar instability, but there is growing support for performing a tibial tubercle osteotomy (TTO) in patients with an elevated tibial tubercle-trochlear groove distance. The purpose of this study was to evaluate the impact of adding a TTO to MPFLR on patient-reported outcomes. MethodsA retrospective review of patients who underwent MPFLR with or without TTO with a minimum of 12-month follow-up was performed. Patients in both groups were matched based on age, gender, and follow-up time. Recurrent instability (including redislocation and subluxation), visual analogue scale (VAS) score, Kujala score, and satisfaction were evaluated. ResultsThere were 59 patients who underwent MPFLR with concomitant TTO performed at our institution and met our inclusion and exclusion criteria. These patients were then matched to patients undergoing isolated MPFLR based on demographics and follow-up time. The mean age was 25.0 years, 76.3% were female, and the mean follow-up time was 49 months. There was a significant difference in mean tibial tubercle-trochlear groove distance (19.8 ± 3.9 vs. 14.1 ± 2.8) between groups. There was no significant difference in VAS (1.48 ± 2.0 vs. 1.49 ± 2.1, p = 0.972), satisfaction (86.1% ± 24.2% vs. 81.2% ± 27.9, p = 0.311) or revision surgeries (10.2% vs. 10.2%) between groups. ConclusionMatched patients undergoing MPFLR with TTO compared with isolated MPFLR demonstrate no statistically significant difference in patient-reported outcomes, levels of pain, and satisfaction postoperatively. Furthermore, the addition of a TTO does not increase the risk of further surgery or complications. Level of evidenceIII, retrospective comparative study.

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.

Development of approaches to treatment of knee instability. Review

Over the past 20 years, interest in the treatment of patellar instability has increased significantly, many actual surgical techniques have been presented in the publications. The article discusses the development of approaches, issues on the treatment of patellar instability, indications and contraindications for different interventions.

Patients unable to return to play following medial patellofemoral ligament reconstructions demonstrate poor psychological readiness.

Medial patellofemoral ligament reconstruction (MPFLR) is often indicated in athletes with lateral patellar instability to prevent recurrence and allow for a successful return to play. In this patient population, the ability to return to play is one of the most important clinical outcomes. The purpose of the current study was to analyze the characteristics of patients who were unable return to play following MPFL reconstruction. A retrospective review of patients who underwent MPFL reconstruction and subsequently did not return to play after a minimum of 12-months of follow-up was performed. Patients were evaluated for their psychological readiness to return to sport using the MPFL-Return to Sport after Injury (MPFL-RSI) score, which is a modification of the ACL-RSI score. A MPFL-RSI score > 56 is considered a passing score for being psychologically ready to return to play. Additionally, reasons for not returning to play including Visual Analog Scale for pain (VAS), Kujala score, satisfaction, and recurrent instability (including dislocations and subluxations) were evaluated. The study included a total of 35 patients who were unable to return to play out of a total cohort of 131 patients who underwent MPFL reconstruction as treatment for patellar instability. Overall, 60% were female with a mean age of 24.5, and a mean follow-up of 38months. Nine patients (25.7%) passed the MPFL-RSI benchmark of 56 with a mean overall score of 44.2 ± 21.8. The most common primary reasons for not returning to play were 14 were afraid of re-injury, 9 cited other lifestyle factors, 5 did not return due to continued knee pain, 5 were not confident in their ability to perform, and 2 did not return due to a feeling of instability. The mean VAS score was 1.9 ± 2.3, the mean Kujala score was 82.5 ± 14.6, and the mean satisfaction was 76.9%. Three patients (8.7%) reported experiencing a patellar subluxation event post-operatively. No patient sustained a post-operative patellar dislocation. Following MPFL reconstruction, patients that do not return to play exhibit poor psychological readiness with the most common reason being fear of re-injury. IV.

Differential anatomy within the femoral origin of the medial patellofemoral complex: Implications or reconstruction

Objectives:The medial patellofemoral complex (MPFC) includes the medial patellofemoral ligament (MPFL) and medial quadriceps tendon femoral ligament (MQTFL). Recent reports have described reconstruction of this fan-shaped ligament to treat patellar instability using a double stranded technique to recreate both components of the complex, with a common origin on the medial femur. Much effort has been placed on accurately identifying the “point” of femoral origin during reconstruction due to the influence of femoral tunnel position on MPFC graft function, however, the MPFC origin is elongated in nature. Therefore, the purpose of this study was to describe the shape and orientation of the MPFC origin and identify the difference between the most proximal and distal margins of the elongated femoral footprint.Methods:20 paired fresh frozen cadaveric knees were dissected. From an intraarticular approach, the MPFC was exposed and followed to its footprint on the medial femur. All other soft tissue was removed from the distal femur, and the footprint of the MPFC, the adductor tubercle and medial epicondyle were marked. Images of the medial femur were analyzed using Image J software. The length and width of the MPFC footprint was described to the nearest 0.1mm, as well as the angle of the long axis of the footprint relative to the axis of the femoral shaft (0.1 degrees). The position of the footprint’s most proximal and distal margins were identified and described in relation to the adductor tubercle and medial epicondyle. The positions for each were compared using paired t tests.Results:17 knees from 10 cadavers (7M, 3F, mean age 73.1) were included in this study. The MPFC femoral footprint had a length of 11.7mm+/-1.8mm (Range 9.6,15.7) and a width of 1.7mm+/-0.4mm (Range, 0.9, 2.2). The long axis of the footprint was found to lie at an angle 14.6+/-16.6 degrees anterior to the axis of the femoral shaft. The most proximal fibers originated 7.4mm+/-3.8mm anterior and 1.8mm+/-4.7mm distal to the adductor tubercle, and 4.1mm+/-2.6mm posterior and 8.4mm+/-5.6mm proximal to the medial epicondyle. The most distal fibers originated 4.9mm+/-4.2mm anterior and 1.3mm+/-4.3mm and distal to the adductor tubercle, as well as 7.1mm+/-2.4mm posterior and 0.5mm+/-5.6mm distal to the medial epicondyle. Overall, the distal margin of the footprint was 10.9mm+/-1.7mm distal (p<0.001) and 2.6mm+/-3.2mm more posterior (p=0.005) than the proximal margin of the MPFC origin.Conclusions:The femoral footprint of the MPFC is ribbon shaped, with the distal margin being 10.9 mm distal and 2.6 mm posterior to the proximal margin. This differential anatomy of the femoral origin suggest that MPFL and MQTFL reconstruction may require separate placements of the femoral tunnels to anatomically recreate these fibers. Further biomechanical studies are needed to determine the optimal femoral tunnel placement in the setting of double-limbed MPFC reconstruction, as well as the long term benefit of this technique in the treatment of patellar instability.

Treatment of a combined deformity following tibial tubercle ventromedialization with single proximal tibial closing wedge osteotomy

Patellar instability in skeletally immature patients must be approached with concern of potential damage to physes. In this article, we present a case of combined knee deformity consisting of genu recurvatum, genu valgum and patella baja which arose subsequent to a pediatric tibial tubercle ventromedialization. Patient was a female who was 22 years old upon first admission. After confirming cartilage to be in good health, the deformity was corrected with a single supratubercular posteriorly and medially based proximal tibial closing wedge osteotomy. At the seventh year follow-up, patient was pain free, functionally satisfied and radiographic evaluation showed correct alignment. This case illustrates the consequent difficulties faced if physeal damage occurs during treatment of patellar instability as well as effectiveness of a single well-planned supratubercular proximal tibial osteotomy treating combined genu recurvatum, genu valgum and patella baja deformities; although anatomic and clinical studies are required to generalize its use.

Tibial Tubercle Osteotomy and Medial Patellofemoral Ligament Imbrication for Patellar Instability Due to Trochlear Dysplasia

Background:The treatment of patellar instability in the setting of trochlear dysplasia is challenging.Purpose/Hypothesis:The purpose of this study was to evaluate outcomes for the treatment of recurrent patellar dislocations due to trochlear dysplasia using anteromedialization tibial tubercle osteotomy combined with medial patellofemoral ligament (MPFL) imbrication. We hypothesized that the treatment of patellar instability with tibial tubercle osteotomy and MPFL imbrication would result in improved patient satisfaction and decrease patellar instability events in patients with prior instability and trochlear dysplasia.Study Design:Case series; Level of evidence, 4.Methods:We performed a retrospective analysis of patients who underwent MPFL imbrication and concomitant anteromedialization tibial tubercle osteotomy for recurrent patellofemoral instability at a single institution. The minimum follow-up was 1 year. Patient demographic information including age at the time of surgery, sex, body mass index (BMI), tibial tubercle–trochlear groove (TT-TG) distance, and grade of trochlear dysplasia was collected along with relevant operative data. Postoperatively, recurrent dislocation events as well as Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index, and Kujala scores were collected, and satisfaction was ascertained by asking patients whether they would undergo the procedure again.Results:A total of 37 knees from 31 patients (23 female) with a mean follow-up of 3.8 years (range, 1-8.9 years) were included. The mean patient age was 28.8 years (range, 14-45 years), the mean BMI was 24 kg/m2 (range, 20-38 kg/m2), and the mean preoperative TT-TG distance was 18.9 mm (range, 8.4-32.4 mm). Two knees were classified as low-grade trochlear dysplasia (Dejour A) and 35 as high-grade trochlear dysplasia (Dejour B-D). At final follow-up, patients reported mean KOOS subscale scores of 86.5 (Pain), 79.8 (Symptoms), 93.9 (Activities of Daily Living), 74.3 (Sports/Recreation), and 61.9 (Quality of Life), as well as a mean Kujala score of 81.3. Mean patient satisfaction was 8.3 of 10. The majority of knees (86.5%; 32/37) remained stable without recurrent instability after this procedure, while 13.5% (5 knees) suffered a recurrent dislocation, with 2 requiring revision surgery. Eight knees (21.6%) underwent subsequent hardware removal.Conclusion:Anteromedialization tibial tubercle osteotomy with MPFL imbrication can improve recurrent patellofemoral instability and provide significant clinical benefit to patients with trochlear dysplasia.

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.

A 2-year follow-up of isolated Medial Patellofemoral Ligament Reconstruction by using soft suture anchor and adjustable cortical fixation system

PurposeNumerous surgical techniques and fixation methods have been described in medial patellofemoral ligament (MPFL) reconstruction such as choice of graft, graft fixation method of patella/femur and initial tension. We describe short term clinical results of MPFL reconstruction by using soft suture anchor and adjustable cortical fixation system. MethodsTwenty-four patients who underwent isolated MPFL reconstruction by using soft suture anchor and adjustable cortical fixation system were included in this study. All patients were followed up for at least 2 years, and pre-operative and 2 years post-operative Kujala score, IKDC score and Knee Injury and Osteoarthritis Outcome Score were used to assess clinical outcome. Radiographic evaluation included the Q angle, congruence angle and patellar tilt angle. Pre- and post-operative changes were evaluated by Mann–Whitney U test. ResultsThere were no complications including re-dislocation, patella fracture, infection, and joint contracture. The apprehension test was positive in 4.2% post-operatively. A statistically significant improvement in clinical scores and radiographic evaluation were evident after surgery. ConclusionsIsolated MPFL Reconstruction using soft suture anchor and adjustable cortical fixation system led good restoration of patellar stability and significant improvement of knee function in short-term results. This surgical technique can reduce complications such as patella fractures, and can be done safely. Clinical relevanceThis technique may be a treatment option with little associated complications in the treatment for patellar instability. Level of EvidenceCase series, Level IV.

THE EVALUATION OF SUPRATROCHLEAR OSSEOUS MORPHOLOGY: AN EPIDEMIOLOGIC STUDY

Introduction: Patellar instability can impede activities of daily life. The morphology of the femoral trochlea has significant involvement in maintaining patellofemoral joint stability. Trochlear dysplasia, or a shallow trochlear groove, has been implicated as a risk factor for recurrent patellar dislocation. A supratrochlear spur in the setting of existing trochlear dysplasia can generate further patellar instability. Trochleoplasty has been popularized by some surgeons for the treatment of recurrent patellar instability in the setting of significant trochlear dysplasia. Despite recommendation of trochleoplasty in treatment of patellar instability in the setting of trochlear dysplasia, much is unknown about the prevalence of trochlear dysplasia and supratrochlear spurs in the general population. The purpose of this study is to investigate the prevalence of supratrochlear spurs and trochlear dysplasia in the population and investigate the relationship between supratrochlear spurs and dysplastic femoral trochleae. Methods: This study was performed at the Cleveland Museum of Natural History, the Hamann Todd Human Osteological Collection. With over 4,000 complete human skeletons, the Hamann Todd osteological collection at the Cleveland Museum of Natural History is the largest collection of osteological specimens with documented demographic data in the Western Hemisphere. We evaluated femora from over 1,000 individuals aged 16-40 years. Each specimen was evaluated for the presence of trochlear dysplasia and supratrochlear spurs. We excluded skeletally immature specimens as well as specimens with visible signs of osteoarthritis or abnormal, bony deformity. The presence or absence of supratrochlear spurs was documented. Abnormal femoral trochleae were photographed in A/P, axial, and lateral views. The width and length of supratrochlear spurs were measured using digital calipers. Results: Of the 1,148 specimens studied, 135 femora from 93 individuals were found to be dysplastic. Amongst these, 9 femora with trochlear dysplasia had supratrochlear spurs. The average age of individuals with dysplastic trochleae in this study was 32.86. Of the 93 specimens identified, 24 were female (25.8%). Additionally, 52% of individuals with dysplastic trochleae were white while 48% were black. Conclusions: There may be an association of supratrochlear spurs with trochlear dysplasia. Though 25.8% of individuals with dysplastic trochleae were female, it is important to note that the Hamann Todd Collection as a whole is 19% female.

Influence of patient-related factors on clinical outcome of tibial tubercle transfer combined with medial patellofemoral ligament reconstruction

BackgroundTibial tubercle transfer is frequently used for treating patellar instability. This study aimed to analyze the clinical results following tibial tuberosity transfer with medial patellofemoral ligament (MPFL) reconstruction in the treatment of patellar instability. MethodsSeventy-two cases presenting a lateralized tibial tubercle were treated with tibial tuberosity transfer and MPFL reconstruction. Pre-operative and postoperative pain levels and knee function were evaluated using common scoring systems. Cartilage status was assessed at the time of surgery, and the influence of patient-related factors was analyzed. Median and interquartile ranges were used to present the results. ResultsAfter a mean of 27.6 (12 -76) months, a re-dislocation rate of 4.2% and significant improvement in knee function from a median of 48.0 (33 -70) to 83.0 (68 -94) and a median of 44.0 (24 -62) to 85.0 (69 -93), based on Kujala (P ≤ 0.001) and Lysholm (P ≤ 0.001) scores were observed. The Tegner score significantly increased from a median of 3.0 (2 -4) to 4.0 (4 -5) (P ≤ 0.001), while the pain level decreased from a median of 5.0 (3 -8) to 2.0 (0 -3) (P ≤ 0.001). Cartilage lesions were found in 55/72 (76.4%) knees. The likelihood of finding II° cartilage lesions was six times higher in cases of ≥ two previous operations. ConclusionTibial tuberosity transfer with MPFL reconstruction allowed reliable patellar stabilization with a low re-dislocation rate. Patient age and unsuccessful attempts at surgical stabilization posed significant risk factors for cartilage lesions and may have limited postopertive outcomes.

Short lateral posterior condyle is associated with trochlea dysplasia and patellar dislocation.

Surgeons mainly consider the anterior anatomy of the distal femur in the treatment of patellar instability (PI) with trochlear dysplasia (TD). Through this research, the idea was to analyse the posterior femoral condyle length in TD. The research team posited the presence of morphological differences in the posterior part of the femoral epiphysis in TD compared to a control group. They also postulated that the posterior bicondylar angle (PCA), in the axial plane, was increased in TD. This is a single-centre morphological study of 100 patients who had a computed tomography (CT) using the same protocol. 50 patients with PI (25 dysplasias A and 25 B-C-D according to the Dejour classification), and 50 controls were included. All patients presenting a clinical PI were considered for the study. None of these patients had undergone a surgical treatment prior to imaging. Demographic characteristics, BMI, and laterality were comparable in all patients. 20 pilot CT scans were used to establish the methodology. The following measurements were performed: anterior bicondylar angle, PCA, and condylar lengths with respect to the surgical transepicondylar axis. Ratios were calculated in relation to the femoral width. TD was classified according to the Dejour classification in grade A or grades B-C-D. An analysis of variance and a linear model were performed within some groups to investigate which parameters correlated with the classification's grade. This study showed a link between TD and the PCA: control group (1.4 ± 0.2°), type A group (1.6 ± 0.3°), and types B, C, D group (2.6 ± 0.3°) (p = 0.01). The difference between the control group and types B, C, D TD group was significant (p = 0.002). In groups B, C, D, the PCA was more important, which proves that in these groups the posterior part of the lateral condyle was relatively shorter compared to the medial condyle. The greater the dysplasia, the longer the medial condyle was in the anterior posterior (p = 0.02). This study shows not only an anterior but also a posterior anomaly in PI with TD. There is a correlation between the severity of the anterior deformation and the PCA: in other words, the knee is placed in valgus in flexure which promotes the external dislocation of the patella. This anatomical study could open a field of research on the development of surgical treatments based on the correction of posterior condylar femoral anomalies in PI. III.

Ratio of the tibial tuberosity–trochlear groove distance to the tibial maximal mediolateral axis: A more reliable and standardized way to measure the tibial tuberosity–trochlear groove distance

BackgroundTibial tuberosity–trochlear groove distance(TT-TG) is a measurement to assist in the diagnosis and treatment of patellar instability, however it still has some limitations. Our study was to modify the accepted measurement method and seek a more reliable and standardized method. MethodsThe data of 65 healthy controls and 49 patients with bilateral patellar instability from 2010 to 2016 were collected and analyzed by CT. The TT-TG, tibial maximal mediolateral axis (MML), and their ratio [i.e., the modified-TT-TG (M-TT-TG)] were compared between the two groups. ResultsThe MML (71.9±12.0 vs. 71.3±10.9) was not significantly different between the two groups (P>0.05). However, the TT-TG(18.1±6.0 vs. 13.1±2.9) and M-TT-TG (0.25±0.08 vs. 0.19±0.04) were significantly different between the two groups (P<0.05). A TT-TG of >15mm was found in 24.5% of healthy controls and 71.5% of patients. The healthy controls with a TT-TG of >15mm were compared with the patients; although no significant difference was found in the TT-TG (16.8±1.5 vs. 18.1±6.0), the healthy controls had a significantly larger MML (76.9±12.7 vs. 71.9±10.9) and significantly smaller M-TT-TG (0.22±0.04 vs. 0.25±0.08). A total of 53.1% of patients but only 6.9% of healthy controls had an M-TT-TG of >0.25. ConclusionThe M-TT-TG is a more reliable and standardized way to measure the effect of the TT-TG with the goal of reducing the false-positive rate associated with the standard measurement technique. The normal M-TT-TG ranges from 0.11 to 0.25, with an M-TT-TG of >0.25 being associated with patellofemoral malalignment. Level of evidenceIII.