scholarly journals Outcomes of MPFL reconstruction with tibial tubercle transfer for recurrent patellar instability with high grade trochlear dysplasia in Indian population

2021 ◽  
pp. 101490
Author(s):  
Sujit Jos ◽  
S. Shankar ◽  
Rajeev Anand ◽  
Libin Thomas Manathara ◽  
Bobby Paulos
Keyword(s):  
Patellar Instability ◽  
Indian Population ◽  
Trochlear Dysplasia ◽  
Mpfl Reconstruction ◽  
Tibial Tubercle ◽  
High Grade ◽  
Tibial Tubercle Transfer ◽  
Recurrent Patellar Instability

scholarly journals Isolated Medial Patellofemoral Ligament Reconstruction for Patellar Instability Regardless of the Tibial Tubercle Trochlear Groove Distance: Outcomes at 1 and 2 Years

2018 ◽  
Vol 6 (7_suppl4) ◽  
pp. 2325967118S0007
Author(s):  
Brandon J. Erickson ◽  
Joseph Nguyen ◽  
Katelyn Gasik ◽  
Jacqueline Brady ◽  
Beth E. Shubin Stein
Keyword(s):  
Patellar Instability ◽  
Medial Patellofemoral Ligament ◽  
Trochlear Dysplasia ◽  
Patellar Height ◽  
Mpfl Reconstruction ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
One Year ◽  
Recurrent Patellar Instability

Background: Several surgical options exist for treatment of recurrent patellar instability. The treatments can be divided into ligamentous and bony procedures. It is currently unclear which patients require a bony procedure in addition to a soft tissue reconstruction. Purpose: To report the one and two-year outcomes of patients following medial patellofemoral ligament (MPFL) reconstruction performed in isolation regardless of the patellar height, tibial tubercle trochlear groove distance (TT-TG) or trochlear dysplasia. Hypothesis:: Patients will have <5% re-dislocation rate and significant improvements in patient reported outcome measures (PROMs) following isolated MPFL reconstruction. Methods: All patients with recurrent patellar instability and without significant unloadable chondral defects, failed previous surgery or pain greater than or equal to 50% as their chief complaint, were prospectively enrolled beginning March of 2014. All patients underwent a primary, unilateral, isolated MPFL reconstruction regardless of concomitant bony pathology for treatment of recurrent patellar instability. Patients were followed at standard intervals. PROMs were collected at one year and two year follow up visits. Information on recurrent subjective instability, dislocations, and ability to return to sport (RTS) was recorded. TT-TG and patellar height (using the Caton-Deschamps index) were measured on magnetic resonance images. Results: Overall, 90 patients (77% female; average age 19.4 +/- 5.6 years) underwent a MPFL reconstruction from March 2014 to August 2017; 63 (70%) of whom reached one year follow up, and 35 of these patients (39%) reached 2-year follow-up. No patient experienced a redislocation; 96% of patients at one year and 100% of patients at two years had no subjective patellofemoral instability. RTS rates at one and two years were 59% and 75% respectively. No patient experienced a complication at one year. All patients had a clinically and statistically significant improvement from baseline to 1-year follow-up in the following PROMs: Knee injury and Osteoarthritis Outcome Score Quality of Life (KOOS QOL) (32.7 to 72.0; p<0.001), International Knee Documentation Committee (IKDC) (51.4 to 82.6; p<0.001) Kujala (62.2 to 89.5; p<0.001), and all general health PROM. No clinically and statistically significant change was seen between 1- and 2-year follow-ups in all outcome scores (all p>0.05). A non-statistically significant increase was seen in sporting activity of the Pediatric Functional Activity Brief Scale (Pedi-FABS) (13.9 to 16.7 p=0.292) at 2 years. Average patient satisfaction was 9.3 of 10 (10 being most satisfied) at 1- and 2-year follow-up. Average TT-TG was 15.1 +/- 4.0. Average patellar height was 1.25 +/- 0.17. Conclusion: Isolated MPFL reconstruction is an effective treatment for patellar instability and provides significant improvements in PROMs with a low redislocation/instability rate at early 1 and 2 year follow up, regardless of bony pathologies including TT-TG, Caton-Deschamps Index and trochlear dysplasia. The goal of this ongoing prospective study is to follow these patients out for 5 to 10 years to assess what radiologic and physical examination factors predict failure of isolated MPFL reconstruction.

Clinical Outcomes and Predictive Factors for Failure With Isolated MPFL Reconstruction for Recurrent Patellar Instability: A Series of 211 Reconstructions With a Minimum Follow-up of 3 Years

2019 ◽  
Vol 47 (6) ◽  
pp. 1323-1330 ◽  
Author(s):  
Elliot Sappey-Marinier ◽  
Bertrand Sonnery-Cottet ◽  
Padhraig O’Loughlin ◽  
Herve Ouanezar ◽  
Levi Reina Fernandes ◽  
...  
Keyword(s):  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Patella Alta ◽  
Mpfl Reconstruction ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Kujala Score ◽  
The Mean ◽  
Recurrent Patellar Instability

Background: Reconstruction of the medial patellofemoral ligament (MPFL) is widely acknowledged as an integral part of the current therapeutic armamentarium for recurrent patellar instability. The procedure is often performed with concomitant bony procedures, such as distalization of the tibial tuberosity or trochleoplasty in the case of patella alta or high-grade trochlear dysplasia, respectively. At the present time, few studies have evaluated the clinical effectiveness of MPFL reconstruction as an isolated intervention. Purpose: To report the clinical outcomes of isolated MPFL reconstruction in cases of patellar instability and to identify predictive factors for failure. Study Design: Case series; Level of evidence, 4. Methods: A retrospective analysis of prospectively collected data was performed, including all patients who had undergone isolated MPFL reconstruction between January 2008 and January 2014. Preoperative assessment included the Kujala score, assessment of patellar tracking (“J-sign”), and radiographic features, such as trochlear dysplasia according to Dejour classification, patellar height with the Caton-Deschamps index (CDI), tibial tubercle–trochlear groove distance, and patellar tilt. The Kujala score was assessed postoperatively. Failure was defined by a postoperative patellar dislocation or surgical revision for recurrent patellar instability. Results: A total of 239 MPFL reconstructions were included; 28 patients (11.7%) were uncontactable and considered lost to follow-up. Thus, 211 reconstructions were analyzed with a mean follow-up of 5.8 years (range, 3-9.3 years). The mean age at surgery was 20.6 years (range, 12-48 years), and 55% of patients were male. Twenty-seven percent of patients had a preoperative positive J-sign, and 93% of patients had trochlear dysplasia (A, 47%; B, 25%; C, 15%; D, 6%). The mean CDI was 1.2 (range, 1.0-1.7); mean tibial tubercle–trochlear groove distance, 15 mm (range, 5-30 mm); and mean patellar tilt, 23° (range, 9°-47°). The mean Kujala score improved from 56.1 preoperatively to 88.8 ( P < .001). Ten failures were reported that required surgical revision for recurrent patellar instability (4.7%). Uni- and multivariate analyses highlighted 2 preoperative risk factors for failure: patella alta (CDI ≥1.3; odds ratio, 4.9; P = .02) and preoperative positive J-sign (odds ratio, 3.9; P = .04). Conclusion: In cases of recurrent patellar instability, isolated MPFL reconstruction would appear to be a safe and efficient surgical procedure with a low failure rate. Preoperative failure risk factors identified in this study were patella alta with a CDI ≥1.3 and a preoperative positive J-sign.

Isolated Medial Patellofemoral Ligament Reconstruction for Patellar Instability Regardless of Tibial Tubercle–Trochlear Groove Distance and Patellar Height: Outcomes at 1 and 2 Years

2019 ◽  
Vol 47 (6) ◽  
pp. 1331-1337 ◽  
Author(s):  
Brandon J. Erickson ◽  
Joseph Nguyen ◽  
Katelyn Gasik ◽  
Simone Gruber ◽  
Jacqueline Brady ◽  
...  
Keyword(s):  
Patellar Instability ◽  
Medial Patellofemoral Ligament ◽  
Trochlear Dysplasia ◽  
Patellar Height ◽  
Mpfl Reconstruction ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Outcome Scores ◽  
Recurrent Patellar Instability

Background: It is unclear which patients with recurrent patellar instability require a bony procedure in addition to medial patellofemoral ligament (MPFL) reconstruction. Purpose: To report 1- and 2-year outcomes of patients after isolated MPFL reconstruction performed for patellar instability regardless of patellar height, tibial tubercle–trochlear groove (TT-TG) distance, or trochlear dysplasia. Study Design: Case series; Level of evidence, 4. Methods: All patients with recurrent patellar instability and without significant unloadable chondral defects (Outerbridge grade IV), cartilage defects (especially inferior/lateral patella), previous failed surgery, or pain >50% as their chief complaint were prospectively enrolled beginning March 2014. All patients underwent primary, unilateral, isolated MPFL reconstruction regardless of concomitant bony pathology for treatment of recurrent patellar instability. Information on recurrent subjective instability, dislocations, ability to return to sport (RTS), and outcome scores was recorded at 1 and 2 years. TT-TG distance, patellar height (with the Caton-Deschamps index), and trochlear depth were measured. Results: Ninety patients (77% female; mean ± SD age, 19.4 ± 5.6 years) underwent MPFL reconstruction between March 2014 and August 2017: 72 (80%) reached 1-year follow-up, and 47 (52.2%) reached 2-year follow-up (mean follow-up, 2.2 years). Mean TT-TG distance was 14.7 ± 5.4 mm (range, –2.2 to 26.8 mm); mean patellar height, 1.2 ± 0.11 mm (range, 0.89-1.45 mm); and mean trochlear depth, 1.8 ± 1.4 mm (range, 0.05-6.85 mm). Ninety-six percent of patients at 1 year and 100% at 2 years had no self-reported patellofemoral instability; 1 patient experienced a redislocation at 3.5 years. RTS rates at 1 and 2 years were 90% and 88%, respectively. Mean time to RTS was 8.8 months. All patients had clinically and statistically significant improvement in mean Knee injury and Osteoarthritis Outcome Score–Quality of Life (32.7 to 72.0, P < .001), mean International Knee Documentation Committee subjective form (51.4 to 82.6, P < .001), and mean Kujala score (62.2 to 89.5, P < .001). No difference existed between 1- and 2-year outcome scores (all P > .05). Conclusion: At early follow-up of 1 and 2 years, isolated MPFL reconstruction is an effective treatment for patellar instability and provides significant improvements in outcome scores with a low redislocation/instability rate regardless of bony pathologies, including TT-TG distance, Caton-Deschamps index, and trochlear dysplasia. Future data from this cohort will be used to assess long-term outcomes.

Current Concepts Regarding Patellofemoral Trochlear Dysplasia

2020 ◽  
pp. 036354652095842
Author(s):  
Benjamin J. Levy ◽  
Miho J. Tanaka ◽  
John P. Fulkerson
Keyword(s):  
Articular Cartilage ◽  
Patellar Instability ◽  
Imaging Techniques ◽  
Trochlear Dysplasia ◽  
Quadriceps Tendon ◽  
Tibial Tubercle ◽  
3 Dimensional ◽  
Tibial Tubercle Transfer ◽  
Complex Structural ◽  
Recurrent Patellar Instability

Optimal treatment of patients with patellofemoral trochlear dysplasia and recurrent patellar instability requires in-depth understanding of this complex structural anomaly. An extensive review of the literature suggests that dysplasia occurs as a result of aberrant forces applied to the patellofemoral joint in the majority of cases. Evidence supports surgical stabilization that reconstructs the medial patellofemoral and/or medial quadriceps tendon–femoral ligament without added trochleoplasty in the majority of patients with trochlear dysplasia and recurrent patellar instability. Adding tibial tubercle transfer distally, medially, or anteromedially in those who need it to treat specific deficits in alignment or articular cartilage can be beneficial in selected patients with trochlear dysplasia and recurrent patellar instability. Trochleoplasty may be appropriate in those few cases in which permanent stable patellofemoral tracking cannot be restored otherwise, but the indications are not yet clear, particularly as trochleoplasty adds risk to the articular cartilage. Improved understanding of imaging techniques and 3-dimensional reproductions of dysplastic patellofemoral joints are useful in surgical planning for patients with recurrent patellar instability and trochlear dysplasia.

scholarly journals Clinical outcomes and predictive factors for failure with MPFL reconstruction combined with tibial tubercle osteotomy and lateral retinacular release for recurrent patellar instability

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Peng Su ◽  
Xiumin Liu ◽  
Nengri Jian ◽  
Jian Li ◽  
Weili Fu
Keyword(s):  
Risk Factors ◽  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Female Gender ◽  
Mpfl Reconstruction ◽  
Tibial Tubercle ◽  
Potential Risk Factors ◽  
The Mean ◽  
Postoperative Dislocation ◽  
Recurrent Patellar Instability

Abstract Background Medial patellofemoral ligament (MPFL) reconstruction combined with tibial tubercle osteotomy (TTO) and lateral retinacular release (LRR) is one of the main treatment methods for patellar instability. So far, few studies have evaluated the clinical effectiveness and assessed potential risk factors for recurrent patellar instability. Purpose To report the clinical outcomes of MPFL reconstruction combined with TTO and LRR at least three years after operation and to identify potential risk factors for recurrent patellar instability. Methods A retrospective analysis of medical records for patients treated with MPFL, TTO and LRR from 2013 to 2017 was performed. Preoperative assessment for imaging examination included trochlear dysplasia according to Dejour classification, patella alta with the Caton-Deschamps index (CDI), tibial tubercle–trochlear groove distance. Postoperative assessment for knee function included Kujala, IKDC and Tegner scores. Failure rate which was defined by a postoperative dislocation was also reported. Results A total of 108 knees in 98 patients were included in the study. The mean age at operation was 19.2 ± 6.1 years (range, 13–40 years), and the mean follow-up was 61.3 ± 15.4 months (range, 36–92 months). All patients included had trochlear dysplasia (A, 24%; B, 17%; C, 35%; D, 24%), and 67% had patellar alta. The mean postoperative scores of Tegner, Kujala and IKDC were 5.3 ± 1.3 (2–8), 90.5 ± 15.5 (24–100) and 72.7 ± 12.1 (26–86). Postoperative dislocation happened in 6 patients (5.6%). Female gender was a risk factor for lower IKDC (70.7 vs 78.1, P = 0.006), Tegner (5.1 vs 6.0, P = 0.006) and Kujala (88.2 vs 96.6, P = 0.008). Age (p = 0.011) and trochlear dysplasia (p = 0.016) were considered to be two failure factors for MPFL combined with TTO and LRR. Conclusion As a surgical method, MPFL combined with TTO and LRR would be a reliable choice with a low failure rate (5.6%). Female gender was a risk factor for worse postoperative outcomes. Preoperative failure risk factors in this study were age and trochlear dysplasia. Level of Evidence Level IV; Case series

scholarly journals Identifying Patients With Patella Alta and/or Severe Trochlear Dysplasia Through the Presence of Patellar Apprehension in Higher Degrees of Flexion

2020 ◽  
Vol 8 (6) ◽  
pp. 232596712092548
Author(s):  
Matthew Colatruglio ◽  
David C. Flanigan ◽  
Sarah Harangody ◽  
Robert A. Duerr ◽  
Christopher C. Kaeding ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Patella Alta ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Type B ◽  
Level Of Evidence ◽  
Sulcus Angle ◽  
Recurrent Patellar Instability

Background: Recurrent patellar instability is frequently treated surgically with reconstruction of the medial patellofemoral ligament (MPFL). Patients with significant patella alta, trochlear dysplasia, and/or an elevated tibial tubercle–trochlear groove (TT-TG) distance may benefit from a concurrent bony procedure such as tibial tubercle osteotomy or trochleoplasty. The indications to perform such procedures are traditionally based on imaging criteria but remain controversial. Patellar apprehension is common in patients with patellar instability but typically resolves in higher degrees of knee flexion. Hypothesis: The persistence of patellar apprehension at greater than 60° of knee flexion is associated with patella alta, an increased TT-TG distance, and trochlear dysplasia. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 76 patients with recurrent patellar instability were prospectively identified in a sports medicine clinic. Patellar apprehension was evaluated in each patient. Apprehension was defined as the patient reporting that the patella felt unstable to lateral patellar translation. Apprehension was first assessed at full knee extension and repeatedly assessed as the knee was flexed in 10° intervals, as measured using a goniometer. The degree of flexion at which patellar apprehension disappeared was recorded. Plain radiographs and magnetic resonance imaging (MRI) scans were obtained for all patients. Patellar height was assessed with the Caton-Deschamps (CD) index, and trochlear morphology was assessed through measurements of the sulcus angle and depth on MRI and classified using the Dejour classification system. Imaging measurements of patients in whom apprehension resolved by 60° of knee flexion were compared with measurements for those with apprehension that persisted deeper into flexion. Results: Apprehension resolved by 60° of flexion in 56 patients and persisted into deeper flexion in 20 patients. The patients with a delayed resolution of apprehension demonstrated a higher CD index; elevated TT-TG distance; increased sulcus angle; decreased sulcus depth; and higher incidence of Dejour type B, C, or D dysplasia (all P < .05). Of the 20 patients with a delayed resolution of apprehension, 18 had either Dejour type B, C, or D dysplasia or a CD index of at least 1.30. A delayed resolution of apprehension was present in 11 of the 16 patients with Dejour type B, C, or D dysplasia. Conclusion: Overall, 90% of patients with significant patella alta and the majority of patients with high-grade trochlear dysplasia demonstrated patellar apprehension that persisted beyond 60° of knee flexion. Additionally, 90% of patients with persistent apprehension had significant patella alta and/or trochlear dysplasia. Further work is needed to evaluate the utility of these findings to inform surgical decision-making in this population.

scholarly journals Isolated MPFL reconstruction for recurrent lateral patellar instability in patients with TT-TG distance <25 mm: A calculated safe risk!

2021 ◽  
Vol 0 ◽  
pp. 1-7
Author(s):  
Sumant Chacko Verghese ◽  
Santosh K. Sahanand ◽  
Nikhil Joseph Martin ◽  
Abhay Harsh Kerketta ◽  
Prashanth Chalasani ◽  
...  
Keyword(s):  
Functional Outcome ◽  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Treatment Algorithm ◽  
Patella Alta ◽  
Mpfl Reconstruction ◽  
Long Term Results ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Study Population

Objectives: The objectives of the study were to describe the surgical technique of our modification of isolated medial patellofemoral ligament (MPFL) reconstruction, in patients with patellar instability. As per literature, isolated MPFL reconstruction is advocated if tibial tubercle-trochlear groove (TTTG) <20 mm. Our study proposes isolated MPFL reconstruction in patients with TT-TG <25 mm and aims to determine any predisposing anatomic variants to aid in the treatment algorithm. Materials and Methods: A retrospective analysis of 52 patients with patellar instability (TT-TG <25 mm), who underwent isolated MPFL reconstruction was undertaken. The study population was divided into two groups; TT-TG <20 mm and TT-TG = 20–24 mm. Both groups were assessed radiologically and on the basis of clinical and functional outcome (KUJALA score), over 5-year follow-up period. Results: The mean age of the study population was 21.98 years, with a female (63.5%) majority. Among the 52 patients included in the study, 39 patients (75%) had TT-TG <20 mm and 13 patients (25%) had TT-TG = 20–24 mm. We noticed statistically significant improvement in both groups with respect to clinical and functional outcome, with no reported complications. None of the patients had patella alta or high grades of trochlear dysplasia. Conclusion: MPFL reconstruction without concomitant bony procedures can be safely performed in patients with a TT-TG <25 mm, in the absence of patella alta or high-grade trochlear dysplasia. Our modification of isolated MPFL reconstruction has shown excellent long-term results. In addition, our technique uses only a single interference screw, thereby reducing cost of surgery and implant hardware.

scholarly journals Manipulation Under Anesthesia With Lysis of Adhesions Is Effective in Arthrofibrosis After Sulcus-Deepening Trochleoplasty: A Prospective Study

2019 ◽  
Vol 7 (8) ◽  
pp. 232596711986486 ◽  
Author(s):  
S. Evan Carstensen ◽  
Scott M. Feeley ◽  
David R. Diduch
Keyword(s):  
Physical Therapy ◽  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Case Series ◽  
Tibial Tubercle ◽  
P Value ◽  
Manipulation Under Anesthesia ◽  
Number Of Patients ◽  
Recurrent Patellar Instability

Background: Sulcus-deepening trochleoplasty has been established as an effective treatment for patellar instability due to trochlear dysplasia. However, arthrofibrosis is a known complication following trochleoplasty, which may require manipulation under anesthesia (MUA) with or without lysis of adhesions (LOA) to increase the knee range of motion (ROM), especially flexion. Purpose: To prospectively follow patients for ROM improvements and subsequent complications after undergoing MUA with or without LOA in the setting of sulcus-deepening trochleoplasty. Study Design: Case series; Level of evidence, 4. Methods: A total of 76 knees with severe trochlear dysplasia were prospectively enrolled and underwent sulcus-deepening trochleoplasty, with a mean (±SD) follow-up of 32.5 ± 19.3 months. Concomitant procedures included medial patellofemoral ligament reconstruction, lateral retinacular release, and tibial tubercle osteotomy. Physical examination including ROM and findings of recurrent patellar instability were collected for all patients. Arthrofibrosis was defined as active and passive flexion less than 90° within 3 months of surgery combined with a plateau in progress with physical therapy. Paired-samples and independent-samples t tests were used. A P value less than .05 was considered significant. Results: A total of 62 knees met inclusion and exclusion criteria and were included in the study. Of these patients, 11 experienced arthrofibrosis as a complication and underwent MUA within 3 months of their index procedure. Of these 11 patients, 9 subsequently underwent arthroscopic LOA following MUA because acceptable ROM could not be achieved with manipulation alone. Patients with arthrofibrosis had a premanipulation mean ROM that was significantly different from those without arthrofibrosis (77.3° ±18.6° vs 133.3° ± 12.7°, respectively; P < .001). In the arthrofibrotic group, postoperative ROM increased significantly after MUA and/or LOA compared with the preoperative ROM (127.3° ± 12.5° vs 77.3° ± 18.6°, respectively; P < .001). ROM in the arthrofibrotic group after MUA/LOA was not significantly different from that in the nonarthrofibrotic group (flexion, 127.3° ± 12.5° vs 133.3° ± 12.7°, respectively; P = .156). No complications from the MUA or LOA were reported at subsequent follow-up visits. Conclusion: When indicated in the setting of severe trochlear dysplasia, sulcus-deepening trochleoplasty is a treatment for disabling recurrent patellar instability with a known complication of arthrofibrosis. Initiation of postoperative physical therapy within 3 days of surgery may reduce the incidence of arthrofibrosis. If arthrofibrosis is encountered after a sulcus-deepening trochleoplasty, MUA without LOA is not as effective as when following other procedures of the knee, whereas MUA with LOA is an effective procedure likely to result in ROM and patient outcome scores similar to those of a nonarthrofibrotic knee after the same procedure. Both MUA and LOA appear to be safe based on the limited number of patients in this study without complication.

scholarly journals The Presence of Patellar Apprehension in Higher Degrees of Flexion Identifies Patients with Patella Alta and or Severe Trochlear Dysplasia

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0034
Author(s):  
Matthew Colatruglio ◽  
David Flanigan ◽  
Sarah Harangody Robert Magnussen
Keyword(s):  
Sports Medicine ◽  
Knee Flexion ◽  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Patella Alta ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Sulcus Angle ◽  
Plain Films ◽  
Recurrent Patellar Instability

Objectives: Recurrent patellar instability is frequently treated surgically with reconstruction of the medial patellofemoral ligament (MPFL). Patients with significant patella alta, trochlear dysplasia, and/or an elevated tibial tubercle-trochlear groove (TT-TG) distance may benefit from a concurrent bony procedure such as a tibial tubercle osteotomy or trochleoplasty. The indications to include such procedures are traditionally based on imaging criteria, but remain controversial. Patellar apprehension is common in patients with patellar instability but typically resolves in higher degrees of knee flexion. We hypothesis that the persistence of patellar apprehension at greater than 60 degrees of knee flexion is associated with patella alta, increased TT-TG distance, and trochlear dysplasia. Methods: Seventy-six patients with recurrent patellar instability were prospectively identified in a sports medicine clinic. Patellar apprehension was evaluated in each patient. Apprehension was defined as the patient reporting that the patella felt unstable to lateral patellar translation. Apprehension was first assessed at full knee extension and repeated assessed as the knee was flexed in 10 degrees intervals as measured with a goniometer. The degree of flexion at which patellar apprehension disappeared was recorded. Plain films and MRI were obtained in all patients. Patellar height was assessed with the Caton-Deschamps (CD) index and trochlear morphology was assessed through measurement of the sulcus angle and depth on MRI and classification with the Dejour classification system. Imaging measurements of patients in which apprehension resolved by 60 degrees of knee flexion were compared with measures for those with apprehension that persisted deeper into flexion. Results: Apprehension resolved by 60 degrees of flexion in 55 patients and persisted into deeper flexion in 21 patients. The patients with delayed resolution of apprehension demonstrated a higher CD Index, elevated TT-TG distance, increased higher sulcus angle, decreased trochlear depth, and a higher incidence of Dejour B, C, or D dysplasia (all p < 0.05, Table 1). Of the 21 patients with delayed resolution of apprehension, 18 had either Dejour B, C, or D dysplasia or a Caton-Deschamps Index of at least 1.3. Delayed resolution of apprehension was present in 11 of the 16 patients with Dejour B, C, or D dysplasia. Conclusion: The presence of patellar apprehension in higher degrees of knee flexion is associated with patella alta, increased TT-TG distance, and more severe trochlear dysplasia. Further work is needed to evaluate utility of this exam finding to inform surgical decision-making in this population.

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