Background: A trend toward young women being at greatest risk for primary and recurrent dislocation of the patella is evident in the current literature. However, a causative factor is missing, and differences in the anatomical risk factors between men and women are less defined.
Purpose: To identify differences between the sexes in the anatomy of lateral patellar instability.
Study Design: Case control study; Level of evidence, 3.
Methods: Knee magnetic resonance images were collected from 100 patients treated for lateral patellar instability. Images were obtained from 157 patients without patellar instability who served as controls. Using 2-way analyses of variance, the influence of patellar dislocation, gender, and their interaction were analyzed with regard to sulcus angle, trochlear depth, trochlear asymmetry, patellar height, and the tibial tubercle–trochlear groove (TT-TG) distance. Mechanisms of injury of first-time dislocations were divided into high-risk, low-risk, and no-risk pivoting activities and direct hits.
Results: For all response variables, a significant effect was observed for the incidence of patellar dislocation (all P < .01). In addition, sulcus angle, trochlear asymmetry, and trochlear depth depended significantly on gender (all P < .01) but patellar height did not (P = .13). A significant interaction between patellar dislocation and gender was observed for the TT-TG distance (P = .02). The mean difference in TT-TG distance between study and control groups was 4.1 mm for women (P < .01) and 1.6 mm for men (P = .05). Low-risk and no-risk pivoting injuries were most common in women, whereas first-time dislocations in men occurred mostly during high-risk pivoting activities (P < .01).
Conclusion: The data from this study indicate that trochlear dysplasia and the TT-TG distance is more prominent in women who dislocate the patella. Both factors might contribute to an increased risk of lateral patellar instability in the female patient as illustrated by the fact that dislocations occurred most often during low-risk or no-risk pivoting activities in women.
AlemparteJEkdahlMBurnierL. Patellofemoral evaluation with radiographs and computed tomography scans in 60 knees of asymptomatic subjects. Arthroscopy. 2007;23:170-177.
2.
AmisAAOguzCBullAMSenavongseWDejourD. The effect of trochleoplasty on patellar stability and kinematics: a biomechanical study in vitro. J Bone Joint Surg Br. 2008;90:864-869
3.
AmisAASenavongseWBullAM. Patellofemoral kinematics during knee flexion-extension: an in vitro study. J Orthop Res. 2006;24:2201-2211.
4.
ArendtEAFithianDCCohenE. Current concepts of lateral patella dislocation. Clin Sports Med. 2002;21:499-519.
5.
AtkinDMFithianDCMarangiKSStoneMLDobsonBEMendelsohnC. Characteristics of patients with primary acute lateral patellar dislocation and their recovery within the first 6 months of injury. Am J Sports Med. 2000;28:472-479.
6.
BuchnerMBaudendistelBSaboDSchmittH. Acute traumatic primary patellar dislocation: long-term results comparing conservative and surgical treatment. Clin J Sport Med. 2005;15:62-66.
7.
CarrillonYAbidiHDejourDFantinoOMoyenBTran-MinhVA. Patellar instability: assessment on MR images by measuring the lateral trochlear inclination-initial experience. Radiology. 2000;216:582-585.
8.
CashJDHughstonJC. Treatment of acute patellar dislocation. Am J Sports Med. 1988;16:244-249.
9.
DejourDLe CoultreB. Osteotomies in patello-femoral instabilities. Sports Med Arthrosc. 2007;15:39-46.
10.
DejourHWalchGNove-JosserandLGuierC. Factors of patellar instability: an anatomic radiographic study. Knee Surg Sports Traumatol Arthrosc. 1994;2:19-26.
11.
EckhoffDGBurkeBJDwyerTFPringMESpitzerVMVanGerwenDP. The Ranawat award: sulcus morphology of the distal femur. Clin Orthop Relat Res. 1996;331:23-28.
12.
EliasDAWhiteLMFithianDC. Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella. Radiology. 2002;225:736-743.
13.
FellerJAAmisAAAndrishJTArendtEAErasmusPJPowersCM. Surgical biomechanics of the patellofemoral joint. Arthroscopy. 2007;23:542-553.
14.
FithianDCPaxtonEWStoneML. Epidemiology and natural history of acute patellar dislocation. Am J Sports Med. 2004;32:1114-1121.
15.
FulkersonJPPostWR. Disorders of the Patellofemoral Joint. 3rd ed.Baltimore: Williams & Williams; 1997.
16.
GoutallierDBernageauJLecudonnecB. The measurement of the tibial tuberosity. Patella groove distanced technique and results. Rev Chir Orthop Reparatrice Appar Mot. 1978;64:423-428.
InsallJSalvatiE. Patella position in the normal knee joint. Radiology. 1971;101:101-104.
19.
KirschMDFitzgeraldSWFriedmanHRogersLF. Transient lateral patellar dislocation: diagnosis with MR imaging. AJR Am J Roentgenol. 1993;161:109-113.
20.
KoëterSDiksMJAndersonPGWymengaAB. A modified tibial tubercle osteotomy for patellar maltracking: results at two years. J Bone Joint Surg Br. 2007;89:180-185.
21.
KujalaUMOstermanKKormanoMNelimarkkaOHurmeMTaimelaS. Patellofemoral relationships in recurrent patellar dislocation. J Bone Joint Surg Br. 1989;71:788-792.
22.
MillerTTStaronRBFeldmanF. Patellar height on sagittal MR imaging of the knee. AJR Am J Roentgenol. 1996;167:339-341.
23.
MunetaTYamamotoHIshibashiTAsahinaSFuruyaK. Computerized tomographic analysis of tibial tubercle position in the painful female patellofemoral joint. Am J Sports Med. 1994;22:67-71.
24.
NietosvaaraYAaltoKKallioPE. Acute patellar dislocation in children: incidence and associated osteochondral fractures. J Pediatr Orthop. 1994;14:513-515.
25.
NikkuRNietosvaaraYKallioPEAaltoKMichelssonJE. Operative versus closed treatment of primary dislocation of the patella: similar 2-year results in 125 randomized patients. Acta Orthop Scand. 1997;68:419-423.
SchoettlePBZanettiMSeifertBPfirrmannCWFucenteseSFRomeroJ. The tibial tuberosity-trochlear groove distance; a comparative study between CT and MRI scanning. Knee. 2006;13:26-31.
28.
SenavongseWAmisAA. The effects of articular, retinatcular or muscular deficiencies on patellofemoral joint stability: a biomechanical study in vitro. J Bone Joint Surg Br. 2005;87:577-582.
29.
ShihYFBullAMAmisAA. The cartilaginous and osseous geometry of the femoral trochlear groove. Knee Surg Sports Traumatol Arthrosc. 2004;12:300-306.
VainionpaaSLaasonenEPatialaHRusanenMRokkannenP. Acute dislocation of the patella: clinical, radiographic and operative findings in 64 consecutive cases. Acta Orthop Scand. 1986;57:331-333.
32.
van HuyssteenALHendrixMRBarnettAJWakeleyCJEldridgeJD. Cartilage-bone mismatch in the dysplastic trochlea: an MRI study. J Bone Joint Surg Br. 2006;88:688-691.
33.
WardSRTerkMRPowersCM. Patella alta: association with patellofemoral alignment and changes in contact area during weight-bearing. J Bone Joint Surg Am. 2007;89:1749-1755.
