The Fibular Collateral Ligament-Biceps Femoris Bursa An Anatomic Study* Robert F. LaPrade,† MD, and Christopher D. Hamilton, MD From the Division of Sports Medicine, Knee & Shoulder Surgery, Department of Orthopaedics and Rehabilitation, The University of Texas Medical Branch, Galveston, Texas ABSTRACT fibular collateral ligament but without defining the anatomy of this bursa. The anatomy of the fibular collateral ligament-biceps In the course of a series of dissections to identify the femoris bursa is described. The bursa is located lateral anatomy and surgical approach of the posterolateral to the distal of the fibular collateral quarter ligament knee, 13 a bursa was consistently identified medial to the and forms an inverted "J" around the anterior shape anterior arm of the long head of the biceps femoris muscle and anteromedial of the Its most portions ligament. as it crossed the fibular collateral ligament. The purpose distal is to the fibular head where margin just proximal of this study was to identify the prevalence and anatomic the fibular collateral ligament inserts, and its more size of the fibular collateral ligament-biceps femoris proximal aspect is at the superior edge of the anterior bursa, and to describe its relationship to the surrounding arm of the long head of the biceps femoris muscle. We structures. found this structure in all 50 knees dissected; there was a constant anatomic location of the fibular collat- eral ligament-biceps femoris bursa in all specimens. Measurement of the anatomic dimensions of the bursa MATERIALS AND METHODS revealed a mean width of 8.4 mm and a mean height of We made thorough dissections of the lateral aspect of the 18 mm. the and Knowing prevalence, shape, size, knee in 50 cadaveric knees. No paired specimens were anatomic location of this bursa aid the clinician in may used. There were 25 right and 25 left knees from 27 male the differential of lateral knee diagnosis pain. and 23 female cadavers. The average age of the donors was 73.7 years. After the skin and subcutaneous tissues of the lateral aspect of the knee were carefully dissected the iliotibial band was incised in line A number of authors have described bursae around the away, longitudinally with its fibers and retracted both anteriorly and posteri- knee that have clinical significance, including bursae on to the more of the fibular the medial side of the knee around the tibial collateral orly expose superior aspect collateral and the lateral aponeurotic attach- ligament 1, 3, 5,14; but descriptions of a bursa around the ligament ments of the long and short heads of the biceps femoris fibular collateral ligament are rare. Although the presence muscle. 8,10 Once the fibular collateral ligament was iden- of a bursa in this region is acknowledged, the location of the iliotibial band was transected and re- this bursa is not agreed on. 8,10 Furthermore, no descrip- tified, axially tracted both and so that the attach- tion of the size, shape, prevalence, or exact location of such proximally distally ment of the fibular collateral on the femur could a bursa has been provided. Others have reported on sev- ligament be identified. Dissection of the lateral of the eral cases of bursitis in the region of the fibular head and aponeurosis long head of the biceps femoris muscle from the lateral and posterior aspect of the fibular collateral ligament was then performed for better identification of the margins of * Presented at the Second World Congress of Sports Trauma, Orlando, the fibular collateral At this the Flonda, June 1996 ligament. point, proximal t Address correspondence and reprint requests to Robert F LaPrade, MD, three-fourths of the fibular collateral ligament was ex- Department of Orthopaedic Surgery, University of Minnesota, 420 Delaware posed. The more distal portion of the fibular collateral Street SE, Box 492 UMHC, Mmneapohs, MN 55455 was covered arm No author or related institution has received financial benefit from research ligament by the anterior of the long head in this study of the biceps femoris muscle. Downloaded from ajs.sagepub.com at NORTHWESTERN439 UNIV LIBRARY on March 4, 2010 440 We identified the fibular collateral ligament-biceps fem- oris bursa by means of a coronal incision between the anterior arm of the long head of the biceps femoris muscle and its lateral aponeurosis. This incision allowed access to the most superior aspect of the bursa. The interval be- tween the anterior arm and the direct arm attachment of the long head of the biceps femoris muscle was then iden- tified and developed further by a splitting incision be- tween these two structures in the sagittal plane proximal to the bursa. Thus, the anterior arm was dissected sharply away from the direct arm, the main tendinous unit of the long head of the biceps femoris muscle that inserts on the posterolateral aspect of the fibular head just lateral to the fibular styloid. 12 We divided the anterior arm of the biceps approximately 5 cm proximal to the fibular head to sepa- rate it from the main tendinous substance of the long head of the biceps femoris muscle, and the anterior arm of the biceps was then retracted distally. This allowed for iden- tification of the dimensions of the fibular collateral liga- ment-biceps femoris bursa as it lay deep to the anterior arm of the long head of the biceps femoris muscle and superficial to the fibular collateral ligament (Figs. 1 and 2). The attachment of the fibular collateral ligament on the lateral aspect of the fibular head could also be identi- fied at this point. We recorded measurements for each specimen. The fol- lowing dimensions were recorded: total length of the fib- ular collateral ligament (in millimeters); the width be- tween the posterior aspect of the bursa to the posterior aspect of the fibular collateral ligament at the top, middle, and inferior aspect of the bursa (in millimeters); the width between the anterior aspect of the bursa to the anterior aspect of the fibular collateral ligament at the top, middle, and inferior aspect of the bursa (in millimeters); the width of the bursa at its midportion (in millimeters); the total 1. The fibular collateral femoris circumferential coverage of the bursa around the fibular Figure ligament-biceps bursa. of the fibular collateral collateral ligament (in degrees); and the width of the fib- A, photograph ligament-biceps femons bursa. The anterior arm of the head of the ular collateral at its aspect, middle, and long ligament superior femoris muscle is and retracted. The at the middle of the bursa (in millimeters). biceps split coronally probe is located (in the bursa) anteromedially to the fibular For the histologic portion of the study, we prepared collateral ligament. B, the fibular collateral ligament (FCL)- blocks of tissue from the lateral aspect of two knees. We biceps femons bursa and its relationship to adjacent ana- examined a tissue block the at- initially involving bony tomic structures of the lateral knee. tachments of the fibular collateral ligament on the femur and on the fibular head, as well as the overlying biceps expansion. Extraneous tissue was then dissected free. An- tal-most portion of the biceps bursa. Supplemental sec- atomic landmarks and measurements paralleling those in tions were obtained in other orientations. the cadaveric portion of the study were present in all sectioned for and specimens processed histologic staining RESULTS were marked for future identification. We placed these specimens into tissue containers. They were subsequently We identified a sizable fibular collateral ligament-biceps dehydrated and embedded in paraffin blocks. We prepared femoris bursa in all 50 specimens. In all specimens, the thin sections using a microtome and evaluated the histo- fibular collateral ligament-biceps femoris bursa was lo- logic details by standard hematoxylin and eosin staining cated laterally and anterior-anteromedially to the distal procedures. Transverse sections were initially performed aspect of the fibular collateral ligament, just proximal to at the superior-most portion of the biceps bursa. Under the insertion of the fibular collateral ligament onto the gross examination, the fibular collateral ligament, ante- lateral aspect of the fibular head. In all cases, the lateral rior arm of the biceps tendon, biceps bursa, and inferior wall of the fibular collateral ligament-biceps femoris bursa lateral geniculate artery could all be identified within abutted the anterior arm of the long head of the biceps each tissue specimen. We also took sections from the dis- femoris muscle where it crossed the fibular collateral lig- Downloaded from ajs.sagepub.com at NORTHWESTERN UNIV LIBRARY on March 4, 2010 441 The average length of the fibular collateral ligament- biceps femoris bursa measured 18 mm (Table 1). The average length of the fibular collateral ligament from its most proximal origin to its most distal insertion was 71 mm. Therefore, the fibular collateral ligament-biceps fem- oris bursa covered the distal quarter of the fibular collat- eral ligament. The average width of the bursa at its mid- portion was 8.4 mm, with an average of 2.0 mm extending anterior to the fibular collateral ligament, and an average of 2.3 mm extending posteriorly. The anterior extension was more consistently present among specimens (range, 1 to 5 mm) and was part of a pocket that formed anterior to the fibular collateral ligament. The posterior width of the bursa was more variable (range, 2 to 15 mm). The poste- rior aspect of the bursa did not appear to form a pocket around the fibular collateral ligament; the medial aspect of the anterior arm of the biceps tendon usually attached directly to the posterior border of the fibular collateral ligament. Histologic Examination Figure 3A is a photomicrograph ( x 60) of a hematoxylin and eosin preparation.