Femoral insertion site in medial patellofemoral ligament reconstruction

Blatter, Samuel; Fürnstahl, Philipp; Hirschmann, Anna; Graf, Matthias J.; Fucentese, Sandro F.

doi:10.1016/j.knee.2015.11.021

Cited by 15 publications

(7 citation statements)

References 33 publications

(44 reference statements)

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“…There have been some recent publications by Blatter et al and Sanchis-Alfonso et al querying the validity of using the Schottle point and supporting isometric placement. 23,24 This study presents a relatively high dislocation rate as compared with other studies. Our initial protocol for management of patients with borderline radiographic findings included staging of procedures.…”

Section: Discussionmentioning

confidence: 61%

Examination under Anesthesia in Patients with Recurrent Patellar Dislocation: Prognostic Study

2018

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Surgical management of patellar instability is a matter of wide debate. While some authors believe that isolated medial patellofemoral ligament (MPFL) reconstruction is sufficient, others advocate procedures to treat the underlying pathology, namely, patella alta and trochlear dysplasia. Radiological studies have been traditionally used as a determinant of these pathologies and to determine the need for an additional procedure. The value of examination under anesthesia (EUA) in formulating a treatment plan remains unknown. Our aim is to assess the prognostic value of EUA in assessing patients presenting for surgical treatment of recurrent patellar dislocations. We retrospectively reviewed the outcome after surgical treatment of 23 patients who had undergone isolated MPFL reconstruction for recurrent patella dislocation by a single surgeon in our tertiary center. All data were completed at the time of index surgery. Primary outcome was recurrent instability requiring revision surgery. The mean age of the 23 patients undergoing MPFL reconstruction was 17.4 years of age. The median trochlea tuberosity-trochlear groove (TT-TG) distance was 15 mm with a median Caton-Deschamps ratio of 1.3. Of the 23 patients who underwent MPFL reconstruction, 9 failed (39%). Median time to failure was 10.5 months. All patients who failed MPFL reconstruction had a dislocating patella on EUA at >30 degrees of flexion. Radiological assessment of the knee to assess its morphology is essential for preoperative surgical planning for patients with recurrent patellar instability. Cutoff values to determine the need for surgical procedures require a consistent method of imaging and are prone to flaws in measurement. However, we demonstrated that EUA provides valuable additional information toward an appropriate surgical approach.Based on our small cohort, we suggest that patients in whom patella remains dislocated past 30 degrees of knee flexion on EUA are unlikely to benefit from isolated MPFL reconstruction.

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Section: Discussionmentioning

confidence: 61%

Examination under Anesthesia in Patients with Recurrent Patellar Dislocation: Prognostic Study

2018

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“…Weightbearing CT data of 10 healthy volunteers, obtained for a previous study, 3 were used for the 3D simulation. The participants had a mean age of 35 years (range, 25-42 years), a mean weight of 83 kg (range, 62-85 kg), and a mean height of 180 cm (range, 169-190 cm).…”

Section: Methodsmentioning

confidence: 99%

Elongation Patterns of Posterolateral Corner Reconstruction Techniques: Results Using 3-Dimensional Weightbearing Computed Tomography Simulation

Hodel

Hasler

Fürnstahl

et al. 2022

Orthopaedic Journal of Sports Medicine

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Background: The isometric characteristics of nonanatomic and anatomic posterolateral corner (PLC) reconstruction techniques under weightbearing conditions remain unclear. Purpose: To (1) simulate graft elongation patterns during knee flexion for 3 different PLC reconstruction techniques (Larson, Arciero, and LaPrade) and (2) compute the most isometric insertion points of the fibular collateral ligament (FCL) graft strands for each technique and report quantitative radiographic landmarks. Study Design: Descriptive laboratory study. Methods: The authors performed a 3-dimensional simulation of 10 healthy knees from 0° to 120° of flexion using weightbearing computed tomography (CT) scans. The simulation was used to calculate ligament length changes during knee flexion for the PLC reconstruction techniques of Larson (nonanatomic single-bundle fibular sling reconstruction), Arciero (anatomic reconstruction with additional popliteofibular ligament graft strand), and LaPrade (anatomic reconstruction with popliteofibular ligament graft strand and popliteus tendon graft strand). The most isometric femoral insertion points for the FCL graft strands were computed within a 10-mm radius around the lateral epicondyle (LE), using an automatic string generation algorithm (0 indicating perfect isometry). Radiographic landmarks for the most isometric points were reported. Results: Median graft lengthening during knee flexion was similar for the anterior graft strands of all 3 techniques. The posterior graft strands demonstrated significant differences, from lengthening for the Arciero (9.9 mm [range, 6.7 to 15.9 mm]) and LaPrade (10.2 mm [range, 4.1 to 19.7 mm]) techniques to shortening for the Larson technique (−17.1 mm [range, −9.3 to −22.3 mm]; P < .0010). The most isometric point for the FCL graft strands of all techniques was located at a median of 2.2 mm (range, −2.2 to 4.5 mm) posterior and 0.3 mm (range, −1.8 to 3.7 mm) distal to the LE. Conclusion: Overconstraint can be avoided by tensioning the posterior graft strands in the Larson technique in extension, and in the Arciero and LaPrade techniques at a minimum of 60° of knee flexion. The most isometric point was located posterodistal to the LE. Clinical Relevance: The described isometric behavior of nonanatomic and anatomic PLC reconstruction techniques can guide optimal surgical reconstruction and prevent graft lengthening and overconstraint of the lateral compartment in knee flexion. Repetitive graft lengthening has been found to be associated with graft failure, and overconstraint favors lateral compartment pressure and cartilage degeneration.

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“…Weightbearing CT scans of 10 healthy volunteers, acquired for a previous study, 6 were analyzed in a 3D simulation. The mean age of the participants was 35 years (range, 25-42 years), the mean weight was 83 kg (range, 62-85 kg), and the mean height was 180 cm (range, 169-190 cm).…”

Section: Methodsmentioning

confidence: 99%

Elongation Patterns of the Superficial Medial Collateral Ligament and the Posterior Oblique Ligament: A 3-Dimensional, Weightbearing Computed Tomography Simulation

Hodel

Hasler

Fürnstahl

et al. 2022

Orthopaedic Journal of Sports Medicine

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Background: Although length change patterns of the medial knee structures have been reported, either the weightbearing state was not considered or quantitative radiographic landmarks that allow the identification of the insertion sites were not reported. Purpose: To (1) analyze the length changes of the superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL) under weightbearing conditions and (2) to identify the femoral sMCL insertion site that demonstrates the smallest length changes during knee flexion and report quantitative radiographic landmarks. Study Design: Descriptive laboratory study. Methods: The authors performed a 3-dimensional (3D) analysis of 10 healthy knees from 0° to 120° of knee flexion using weightbearing computed tomography (CT) scans. Ligament length changes of the sMCL and POL during knee flexion were analyzed using an automatic string generation algorithm. The most isometric femoral insertion of the sMCL that demonstrated the smallest length changes throughout the full range of motion (ROM) was identified. Radiographic landmarks were reported on an isometric grid defined by a true lateral view of the 3D CT model and transferred to a digitally reconstructed radiograph. Results: The sMCL demonstrated small ligament length changes, and the POL demonstrated substantial shortening during knee flexion ( P = .005). Shortening of the POL started from 30° of flexion. The most isometric femoral sMCL insertion was located 0.6 ± 1.7 mm posterior and 0.8 ± 1.2 mm inferior to the center of the sMCL insertion and prevented ligament length changes >5% during knee flexion in all participants. The insertion was located 47.8% ± 2.7% from the anterior femoral cortex and 46.3% ± 1.9% from the joint line on a true lateral 3D CT view. Conclusion: The POL demonstrated substantial shortening starting from 30° of knee flexion and requires tightening near full extension to avoid overconstraint. Femoral sMCL graft placement directly posteroinferior to the center of the anatomical insertion of the sMCL demonstrated the most isometric behavior during knee flexion. Clinical Relevance: The described elongation patterns of the sMCL and POL aid in guiding surgical medial knee reconstruction and preventing graft lengthening and overconstraint of the medial compartment. Repetitive graft lengthening is associated with graft failure, and overconstraint leads to increased compartment pressure, cartilage degeneration, and restricted ROM.

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Femoral insertion site in medial patellofemoral ligament reconstruction

Cited by 15 publications

References 33 publications

Examination under Anesthesia in Patients with Recurrent Patellar Dislocation: Prognostic Study

Examination under Anesthesia in Patients with Recurrent Patellar Dislocation: Prognostic Study

Elongation Patterns of Posterolateral Corner Reconstruction Techniques: Results Using 3-Dimensional Weightbearing Computed Tomography Simulation

Elongation Patterns of the Superficial Medial Collateral Ligament and the Posterior Oblique Ligament: A 3-Dimensional, Weightbearing Computed Tomography Simulation

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