Purpose
To investigate alterations in technique for medial patellofemoral ligament (MPFL)
reconstruction in the setting of patella alta and describe the effect of these alterations
on MPFL anatomometry.
Methods
Ten cadaveric knees were used. Four candidate femoral attachment sites of MPFL were
tested. The attachment sites were Schottle’s point (SP), 5 mm distal to SP, 5 mm proximal
to SP, and 10 mm proximal to SP. A suture anchor was placed at the upper 40% of the
medial border of the patella with the emanating suture used to simulate the reconstructed
ligament. MPFL maximum length change was calculated through a range of motion between
0° and 110°. Recordings at all 4 candidate femoral attachments sites were repeated
after a flat tibial tubercle osteotomy and transfer to achieve alta as measured by
the Caton–Deschamps Index (CDI) of 1.3, 1.4, and 1.5.
Results
The 10 specimens had an average CDI of 0.99, range 0.87 to 1.16. In the native tibial
tubercle condition, SP was more isometric through 20° to 70° range of motion, or anatomometric,
than any other candidate femoral attachment location. With patella alta with a CDI
of 1.3 and 1.4, attachment site 5 mm proximal to SP exhibited more anatomometry than
SP. With patella alta with a CDI of 1.5, attachment site 10 mm proximal to SP exhibited
more anatomometry than SP.
Conclusions
Increased patella alta significantly alters MPFL anatomometry. With increasing degrees
of patella alta, more proximal candidate femoral attachment sites demonstrate decreased
change in length compared with SP. None of the varied femoral attachments produced
anatomometry over the entirety of the flexion range from 20° to 70°, suggesting that
in cases of significant patella alta, proximalization the femoral attachment site
of MPFL reconstruction may be necessary to achieve an anatomometric MPFL reconstruction.
Clinical Relevance
A standardized, isolated MPFL reconstruction may be prone to failure in the setting
of patella alta, given the anisometry demonstrated. Alternative femoral attachment
sites for MPFL reconstruction should be considered in these patients.
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to ArthroscopyAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- The effects of articular, retinacular, or muscular deficiencies on patellofemoral joint stability: A biomechanical study in vitro.J Bone Joint Surg Br. 2005; 87: 577-582
- Q-angle influences tibiofemoral and patellofemoral kinematics.J Orthop Res. 2001; 19: 834-840
- Indications for medial patellofemoral ligament reconstruction: A systematic review.J Knee Surg. 2016; 29: 543-554
- Surgical technique and rationale for medial patellofemoral ligament reconstruction for recurrent patellar dislocation.Arthrosc J Arthrosc Relat Surg. 2003; 19: 1-9
- Patella alta in patellofemoral instability.Acta Orthop Belg. 1989; 55: 387-393
- Long patellar tendon: Radiographic sign of patellofemoral pain syndrome—a prospective study.Radiology. 1992; 185: 859-863
- Patellar tendon length—the factor in patellar instability?.Knee. 2002; 9: 3-6
- Patella alta and recurrent dislocation of the patella.Clin Orthop Relat Res. 1992; : 265-269
- Patellofemoral contact pressures. The influence of q-angle and tendofemoral contact.J Bone Joint Surg Am. 1984; 66: 715-724
- “Chondromalacia patellae”: Patellar malalignment syndrome.Orthop Clin North Am. 1979; 10: 117-127
- Recurrent dislocation and the high-riding patella.Clin Orthop Relat Res. 1972; 88: 67-69
- Predictors of recurrent instability after acute patellofemoral dislocation in pediatric and adolescent patients.Am J Sports Med. 2013; 41: 575-581
- The docking technique for medial patellofemoral ligament reconstruction: Surgical technique and clinical outcome.Am J Sports Med. 2009; 37: 2021-2027
- Acute dislocation of the patella: Results of conservative treatment.J Trauma. 1977; 17: 526-531
- Epidemiology and natural history of acute patellar dislocation.Am J Sports Med. 2004; 32: 1114-1121
- Acute patellar dislocations. The natural history.Am J Sports Med. 1986; 14: 117-120
- Patellar dislocation. The long-term results of nonoperative management in 100 patients.Am J Sports Med. 1997; 25: 213-217
- Reconstruction of the medial patellofemoral ligament: Clinical outcomes and return to sports.Am J Sport Med. 2014; 42: 1661-1668
- Radiographic landmarks for femoral tunnel placement in medial patellofemoral ligament reconstruction.Am J Sports Med. 2007; 35: 801-804
- Anatomy and biomechanics of the medial patellofemoral ligament.Knee. 2003; 10: 215-220
- The anatomy and isometry of a quasi-anatomical reconstruction of the medial patellofemoral ligament.Knee Surg Sport Traumatol Arthrosc. 2017; 25: 2420-2423
- The medial patellofemoral ligament: Location of femoral attachment and length change patterns resulting from anatomic and nonanatomic attachments.Am J Sports Med. 2012; 40: 1871-1879
- The effect of femoral tunnel position and graft tension on patellar contact mechanics and kinematics after medial patellofemoral ligament reconstruction.Am J Sports Med. 2014; 42: 364-372
- Anisometry of medial patellofemoral ligament reconstruction in the setting of patella alta and increased tibial tubercle-trochlear groove (TT-TG) distance.Arthrosc J Arthrosc Relat Surg. 2016; 32: e10
- The anatomy of the medial part of the knee.J Bone Joint Surg Am. 2007; 89: 2000-2010
- A joint coordinate system for the clinical description of three-dimensional motions: Application to the knee.J Biomech Eng. 1983; 105: 136-144
- Dynamic contact mechanics on the tibial plateau of the human knee during activities of daily living.J Biomech. 2014; 47: 2006-2012
- Variation in tibial tubercle-trochlear groove measurement as a function of age, sex, size, and patellar instability.Am J Sport Med. 2014; 42: 389-393
- Length change behavior of virtual medial patellofemoral ligament fibers during in vivo knee flexion.Am J Sports Med. 2015; 43: 1165-1171
- Medial patellofemoral ligament (MPFL) reconstruction improves radiographic measures of patella alta in children.Knee. 2014; 21: 1180-1184
- Factors of patellar instability an anatomic radiographic study.Knee Surg Sport Traumatol Arthrosc. 1994; 2: 19-26
- Outcomes after the arthroscopic treatment of femoroacetabular impingement in a mixed group of high-level athletes.Am J Sports Med. 2011; 39 (14S-9S (suppl))
- Technical errors during medial patellofemoral ligament reconstruction could overload medial patellofemoral cartilage: A computational analysis.Am J Sports Med. 2006; 34: 1478-1485
- Graft length change and radiographic assessment of femoral drill hole position for medial patellofemoral ligament reconstruction.Knee Surg Sport Traumatol Arthrosc. 2011; 19: 400-407
- Impact of the patella height on the strain pattern of the medial patellofemoral ligament after reconstruction: A computer model-based study.Knee Surg Sport Traumatol Arthrosc. 2017; 25: 3123-3133
Article info
Publication history
Published online: February 05, 2020
Accepted:
January 8,
2020
Received:
July 30,
2019
Footnotes
The authors report the following potential conflict of interest or source of funding: J.T.N. reports grants outside the submitted work to his institution from the Clinical Translational Science Center (CTSC), National Center for Advancing Translational Sciences grant #UL1-RR024996. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding source NCATS. B.E.S.S. reports personal fees from Arthrex, outside the submitted work. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
Identification
Copyright
© 2020 by the Arthroscopy Association of North America
