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Watts RE, Gorbachova T, Fritz RC, Saad SS, Lutz AM, Kim J, Chaudhari AS, Shea KG, Sherman SL, Boutin RD. Patellar Tracking: An Old Problem with New Insights. Radiographics 2023; 43:e220177. [PMID: 37261964 PMCID: PMC10262599 DOI: 10.1148/rg.220177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/14/2022] [Accepted: 10/18/2022] [Indexed: 06/03/2023]
Abstract
Patellofemoral pain and instability are common indications for imaging that are encountered in everyday practice. The authors comprehensively review key aspects of patellofemoral instability pertinent to radiologists that can be seen before the onset of osteoarthritis, highlighting the anatomy, clinical evaluation, diagnostic imaging, and treatment. Regarding the anatomy, the medial patellofemoral ligament (MPFL) is the primary static soft-tissue restraint to lateral patellar displacement and is commonly reconstructed surgically in patients with MPFL dysfunction and patellar instability. Osteoarticular abnormalities that predispose individuals to patellar instability include patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Clinically, patients with patellar instability may be divided into two broad groups with imaging findings that sometimes overlap: patients with a history of overt patellar instability after a traumatic event (eg, dislocation, subluxation) and patients without such a history. In terms of imaging, radiography is generally the initial examination of choice, and MRI is the most common cross-sectional examination performed preoperatively. For all imaging techniques, there has been a proliferation of published radiologic measurement methods. The authors summarize the most common validated measurements for patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Given that static imaging is inherently limited in the evaluation of patellar motion, dynamic imaging with US, CT, or MRI may be requested by some surgeons. The primary treatment strategy for patellofemoral pain is conservative. Surgical treatment options include MPFL reconstruction with or without osseous corrections such as trochleoplasty and tibial tubercle osteotomy. Postoperative complications evaluated at imaging include patellar fracture, graft failure, graft malposition, and medial patellar subluxation. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.
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Affiliation(s)
- Robert E. Watts
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Tetyana Gorbachova
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Russell C. Fritz
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Sherif S. Saad
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Amelie M. Lutz
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Jiyoon Kim
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Akshay S. Chaudhari
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Kevin G. Shea
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Seth L. Sherman
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
| | - Robert D. Boutin
- From the Departments of Radiology (R.E.W., A.M.L., R.D.B.) and
Orthopaedic Surgery (S.L.S.), Stanford University School of Medicine, 300
Pasteur Dr, Stanford, CA 94305-5101; Department of Radiology, Einstein
Healthcare Network and Jefferson Health, Sidney Kimmel Medical College, Thomas
Jefferson University, Philadelphia, PA (T.G.); Department of Musculoskeletal
Radiology, National Orthopedic Imaging Associates, Greenbrae, CA (R.C.F.);
Department of Musculoskeletal Radiology, Atlantic Medical Imaging, Galloway, NJ
(S.S.S.); Department of Radiology, Benning Martin Army Community Hospital, Fort
Benning, GA (J.K.); Departments of Radiology and Biomedical Data Science,
Stanford University, Stanford, CA (A.S.C.); and Department of Orthopaedic
Surgery, Lucile Packard Children’s Hospital at Stanford, Palo Alto, CA
(K.G.S.)
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Huddleston HP, Shewman EF, Knapik D, Yanke AB. Lateral Patellofemoral Ligament Reconstruction: A Biomechanical Comparison of 2 Techniques. Am J Sports Med 2023; 51:446-452. [PMID: 36645040 DOI: 10.1177/03635465221145017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND The importance of maintaining lateral patellar stabilizing structures has been demonstrated by the presence of iatrogenic medial patellar instability after lateral retinacular release (LRR) procedures. In patients with medial patellar instability, lateral patellofemoral ligament (LPFL) reconstruction has been clinically shown to restore patellar stability while improving patient-reported outcomes. However, the biomechanics associated with different LPFL reconstruction techniques remain largely unknown. PURPOSE To (1) investigate whether LPFL reconstruction restores medial patellar translation compared with the intact state after LRR and (2) evaluate for any biomechanical differences between soft tissue and osseous LPFL reconstruction techniques. STUDY DESIGN Controlled laboratory study. METHODS A total of 7 knees were included in the final analysis. The knees were dissected, and the tibia and femur were potted. An eye screw was then placed at the midpoint of the patella perpendicular to the medial surface. A custom jig was constructed to allow for a 1-kg load to be applied to the quadriceps muscle. Medial patellar displacement was investigated at 0°, 10°, 20°, 30°, 45°, 60°, and 90° of knee flexion using a tensile testing machine with a 20-N medial force applied to the patella. Medial patellar displacement was assessed in 4 states: intact, LRR, soft tissue LPFL reconstruction (inserted through incisions in the iliotibial band, quadriceps tendon, and patellar tendon), and osseous LPFL reconstruction. RESULTS The LRR group had significantly greater medial patellar translation compared with the intact group throughout flexion (P < .01 to P = .029). The soft tissue LPFL reconstruction group demonstrated significantly greater medial patellar translation at 30° (P = .020) and 45° (P = .025) compared with the intact group, with less translation compared with the LRR group at all degrees of knee flexion except for 45° (P = .065). The osseous LPFL reconstruction group demonstrated significantly greater medial patellar translation compared with the intact group at 30° of flexion (P = .036), with significantly less translation compared with the LRR group from 0° to 30° (P < .01 to P = .013). The soft tissue LPFL reconstruction group (15.94 ± 2.55 mm) demonstrated significantly greater medial patellar translation at 10° of flexion compared with the osseous LPFL reconstruction group (14.16 ± 2.34 mm) (P = .033). CONCLUSION Soft tissue LPFL reconstruction led to significantly greater medial patellar translation at 30° and 45° compared with the intact state, while osseous LPFL reconstruction produced significantly greater translation only at 30°. Both the soft tissue and the osseous reconstruction techniques resulted in comparable medial patellar translation at all degrees of knee flexion except for 10°, in which osseous reconstruction was more similar to the intact state. CLINICAL RELEVANCE Compared with LRR, soft tissue LPFL reconstruction was able to restore stability against medial patellar translation at most degrees of knee flexion, while osseous LPFL reconstruction did not provide adequate stabilization beyond 30° of flexion. While the LPFL does appear to have osseous insertions, soft tissue reconstruction functioned more similarly to the intact state after LRR.
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Affiliation(s)
| | | | | | - Adam B Yanke
- Rush University Medical Center, Chicago, Illinois, USA
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