8 1. Acetabulum is 15–20 degrees anteverted (flexed) and 45 degrees abducted 2. Femoral neck is anteverted 15 degrees relative to femoral condyle with average neck shaft angle of 126 degrees 3. Hip is a ball-and-socket joint and innately stable secondary to bony architecture; however, secondary stabilization is provided by fibrocartilaginous labrum and capsule; capsule composed of iliofemoral (ligament of Bigelow), ischiofemoral, and pubofemoral ligaments (Fig. 8.1) 4. Normal hip range of motion (ROM) (Fig. 8.2) • 140 degrees’ flexion • 20 degrees’ extension • 80 degrees’ abduction • 20 degrees’ adduction • 40 degrees’ internal rotation • 50 degrees’ external rotation 5. Hip musculature and innervation (Table 8.1) 6. Greater trochanter is insertion site of hip’s short external rotators and abductors, and is a lateral structure; lesser trochanter is insertion site of iliopsoas and is a posterior-medial structure 7. Femoral head receives blood supply contributions from the medial femoral circumflex (branch of profunda femoris), lateral femoral circumflex (branch of profunda femoris), and artery of the ligamentum teres (branch of obturator artery) Fig. 8.1 Hip capsule consisting of (a) iliofemoral, pubofemoral, and (b) ischiofemoral ligaments. (From Schuenke M, Schulte E. General Anatomy and the Musculoskeletal System: Thieme Atlas of Anatomy. New York: Thieme; 2005. Illustration by Karl Wesker.) Fig. 8.2 (a–e) Hip ranges of motion, using the neutral-zero method. (From Schuenke M, Schulte E. General Anatomy and the Musculoskeletal System: Thieme Atlas of Anatomy. New York: Thieme; 2005. Illustration by Karl Wesker.) 8. Primary blood supply in adulthood is from medial femoral circumflex, which provides retrograde flow to head from posterior • Protect medial femoral circumflex artery with medial and posterior hip approaches 9. In adulthood, contributions from lateral femoral circumflex and ligamentum teres are negligible 1. Ischial tuberosity is a posterior structure, and tenderness to palpation can indicate a hamstring origin injury. 2. Adductor longus is a palpable groin structure and tenderness is consistent with a strain (“groin pull”). 3. Positive Trendelenburg sign indicates hip abductor weakness; when the patient is standing on the affected limb, the contralateral pelvis will drop below the horizontal (Fig. 8.3). 1. Indications: labral tears, intra-articular loose bodies, femoroacetabular impingement (FAI), septic arthritis, chondral injuries, synovial disorders 2. Common portals: anterior, anterolateral, and posterolateral • Anterior portal at junction of vertical line drawn from anterior superior iliac spine (ASIS) and horizontal line from tip of greater trochanter; lateral femoral cutaneous nerve and femoral vessels at risk • Anterolateral portal on anterior surface of greater trochanter; superior gluteal nerve at risk Table 8.2 Physical Examination of the Hip
Sports Medicine and Lower Extremity Sports
I. Hip
A. Anatomy
B. Physical Examination (Table 8.2)
C. Hip Arthroscopy
Test Name | Technique | Importance |
Anterior impingement | Passive hip flexion/adduction/internal rotation reproduces symptoms | Indicative of femoroacetabular impingement |
External snapping | Hip flexion (in adducted position) | Iliotibial tract catching/irritation over the greater trochanter |
Internal snapping | Passive movement from external rotation/flexion to extension/internal rotation | Iliopsoas tendon catching/irritation over lesser trochanter1 |
Ober | Inability to adduct past midline with hip extended/abducted in lateral position | Tightness of iliotibial tract |
FAIR | Hip FAIR | Stretch of piriformis may exacerbate symptoms of piriformis syndrome |
Abbreviation: FAIR, flexion/adduction/internal rotation.
1Iliopsoas tendon can also catch on the anterior inferior iliac spine or the iliopectineal ridge
• Posterolateral portal on posterior surface of greater trochanter; sciatic nerve at risk; internally rotate leg to avoid neurologic injury
3. Complications: most common are pudendal nerve palsy from perineal post and neurovascular injury from portals
D. Hip Pathology
1. Bursitis
• Greater trochanteric bursitis
a. Demographic: middle-aged females or female runners training on banked surfaces
b. Presentation: lateral hip pain with tenderness, normal passive ROM, pain with resisted abduction and internal rotation
◦ Associated with tightness of iliotibial (IT) band and positive Ober test. The Ober test is performed with the patient in the lateral position, with the affected hip abducted and extended, with knee extension (or flexion). The test is positive when the patient cannot adduct the hip past the midline from this position.
Fig. 8.3 (a) Normal gait. (b) Contralateral hip drop observed with Trendelenburg gait pattern. (c) Compensatory ipsilateral trunk shift observed with Trendelenburg gait. (From Schuenke M, Schulte E. General Anatomy and the Musculoskeletal System: Thieme Atlas of Anatomy. New York: Thieme; 2005. Illustration by Karl Wesker.)
◦ Tightness of IT band can result in “external” snapping hip
◦ External snapping hip can be palpated over trochanter as IT band slides over it; internal snapping hip produced by passively moving hip from flexed/externally rotated to extended/internally rotated
◦ Coxa saltans
c. Pathology: tendinosis of gluteus medius or minimus tendon
d. Imaging: none, clinical diagnosis
e. Treatment: conservative with nonsteroidal anti-inflammatory drugs (NSAIDs), stretching, rest, corticosteroid injection
◦ Surgical management with debridement of tendon and reattachment (“hip rotator cuff repair”)
◦ In coxa saltans, treat with a Z-plasty of the IT band.
• Iliopsoas bursitis
a. Demographic: young athletes (gymnasts, track athletes) and ballet dancers
b. Presentation: anterior hip pain after repetitive hip flexion/extension
◦ Can result in “internal” snapping (audible snap is heard) and pain when moving hip from flexed/externally rotated to extended/internally rotated
c. Pathology: bursitis between hip capsule and iliopsoas tendon; snapping caused by tendon gliding over iliopectineal line or femoral head
d. Imaging: conventional and dynamic ultrasonography to identify the snapping iliopsoas tendon
e. Treatment: conservative with rest, NSAIDs, hip flexor stretching/strengthening, corticosteroid injection
◦ Surgery rarely indicated; arthroscopic release of iliopsoas tendon
◦ Zona orbicularis is a ring of capsular tissue that provides an arthroscopic landmark for identification of the iliopsoas
2. Musculotendinous injuries (strains/tears)
• Hamstring
a. Consist of semimembranosus, semitendinosus, biceps femoris (long head and short head)
b. Demographic: common injury in all ages; frequent during sprinting
c. Presentation: pain with hip flexion and knee extension, ecchymosis in posterior thigh
d. Pathology: strain or tear, frequently at myotendinous junction
3. Imaging: X-ray—ischial tuberosity avulsion seen in pediatric population; MRI for diagnosis and grading of injury
f. Treatment
◦ Conservative management is the gold standard; protected weight bearing with crutches; stretching and strengthening
◦ Surgical repair considered for high-level athletes with proximal tendon ruptures
• Rectus Femoris
a. Consists of direct and indirect heads; direct (straight) head originates from anterior inferior iliac spine (AIIS), whereas indirect (reflected) head originates from superior acetabular ridge and hip capsule
b. Demographic: young athletes, particularly soccer and football players
c. Presentation: anterior thigh pain (proximal or distal) reproduced with resisted hip flexion
d. Pathology: strains/tears at proximal origin, midsubstance, or at distal insertion
e. Imaging: X-ray useful for identification of bony avulsion at AIIS, common in adolescents
f. Treatment: conservative with rest, NSAIDs, stretching for 4–6 weeks
• Adductor
a. Consists of adductor longus, adductor brevis, adductor magnus
b. Demographic: any athlete
c. Presentation: injury occurs with forced external rotation of an abducted leg; presents with significant groin pain and tenderness to palpation along pubic ramus
d. Pathology: strain of the musculotendinous junction or tear of the origin
e. Imaging: magnetic resonance imaging (MRI): signal at pubis signifying tendinous avulsion
f. Treatment: conservative with rest, ice, NSAIDs, and protected weight bearing; rehabilitation follows with stretching and strengthening
3. Sports Hernia/Athletic Pubalgia
• Demographic: athletes of any age, especially soccer and hockey players, males > females
• Presentation: anterior pelvic or groin pain, without physical exam evidence of inguinal hernia; exacerbated with activities that increase intra-abdominal pressure (Valsalva maneuver, sit-ups, etc.); tenderness over adductor longus origin
a. Secondary to sports with frequent abdominal hyperextension and hip abduction
b. Can be confused with osteitis pubis, where patients have focal tenderness over pubic symphysis and pain with resisted rectus abdominis testing
• Pathology: poorly understood and controversial; due to chronic overuse with microtearing of the anterior abdominal wall (rectus abdominis, obliques, or transversalis fascia) and adductor involvement with associated pubis changes
• Imaging: diagnosis of exclusion; X-ray and MRI are useful to rule out other etiologies, such as osteitis pubis.
• Treatment: conservative with 6–8 weeks of rest and rehabilitation
a. Surgery focused on the site of complaint can be indicated, with pelvic floor reconstruction, adductor release, or rectus reattachment.
b. In patients with chronic adductor pain and normal MRI scans, a single corticosteroid shot has been shown to provide relief.
4. Femoral neck stress fractures
• Demographic: young female athletes, particularly runners
• Presentation: groin pain with weight bearing in athletes who have a history of overuse or recent increase in training; physical exam usually benign
• Pathology: chronic, repetitive loading results in microfractures in femoral neck; seen on tension side (superior-lateral) or compression side (inferiormedial)
• Imaging: X-ray can identify fracture line late in process; MRI is study of choice for identification in patients with normal X-rays
• Treatment
a. Compression-side stress fracture: in compliant patients can be managed conservatively with weight bearing with crutches until pain free and cessation of running for 8–12 weeks.
b. Compression side: conservative management; tension side: surgery
c. Tension-side fracture and injuries spanning > 50% of neck: have a higher propagation rate and surgically treated with percutaneous screw fixation
5. Femoroacetabular impingement (FAI)
• Hip impingement syndrome secondary to abnormal contact between femur and acetabulum
• Demographic: young and middle-aged adults, leading to early-onset hip dysfunction, labral pathology, and secondary arthritis
• Three types of FAI: cam, pincer, and combined
a. Cam: abnormality of the proximal femur including asymmetric femoral head, decreased femoral offset, abnormal head/neck ratio, and retroversion of femoral neck [secondary to old fracture or slipped capital femoral epiphysis (SCFE)]; seen in young athletes
b. Pistol grip deformity is an irregularity of the contour of the superolateral femoral head/neck junction, indicating cam impingement
c. Pincer: abnormality of the acetabulum from acetabular retroversion, acetabular protrusion (“protrusio acetabuli”), coxa profunda (deep acetabulum), and excess anterior-superior acetabular rim; seen in active middle-aged patients
d. The crossover sign on X-ray indicates acetabular retroversion, seen in pincer impingement
e. Combined: involvement of both the femur and acetabulum
• Presentation: activity-related groin pain, particular with deep hip flexion; can report mechanical symptoms; exam reveals limited hip flexion and internal rotation
a. Positive anterior impingement test: reproduction of symptoms with flexion, adduction, and internal rotation
b. Pathology: cam, pincer, or combined mechanisms resulting in labral pathology or chondral degeneration
◦ Labral tears observed within the anterosuperior quadrant of the acetabulum
c. Imaging: X-rays useful in assessment of proximal femur and acetabular anatomy
◦ On anteroposterior (AP) views of the pelvis, evaluate for crossover sign, indicating acetabular retroversion and pincer impingement; assess for pistol-grip deformity of femoral neck/head, indicating cam impingement
◦ False-profile view: important and frequently tested (Fig. 8.4)
♦ Assesses the anterior acetabulum coverage for pincer impingement; performed with 65-degree angle between pelvis and X-ray cassette
◦ Computed tomography (CT): to evaluate bony anatomy
◦ MR arthrogram: to assess labrum
◦ MRI: test of choice to evaluate tear location and pattern; use caution, as false-positive results are common
d. Treatment
◦ Conservative management: most successful for patients with minimal symptoms and no mechanical complaints
◦ Surgical management: open or arthroscopic; open is considered gold standard; however, recent literature indicates similar results with arthroscopic procedures; surgery directed at correcting pathology
◦ Cam: osteochondroplasty of femoral head/neck, possible femoral osteotomy
◦ Pincer: osteochondroplasty of acetabular rim, labral debridement/repair
Fig. 8.4 Depiction of patient position and X-ray beam angle for obtaining false-profile radiographic view.
◦ For patients with significant arthritic changes, hip arthroplasty is indicated.
6. Hip nerve entrapment syndromes
• Ilioinguinal nerve entrapment
a. Pathology: hypertrophied abdominal muscles that results in hyperesthesia and pain
b. Presentation: dysesthesia in groin; numbness exacerbated with hip hyperextension
c. Treatment: conservative, stretching/activity modification; surgical release indicated if symptoms persist
• Obturator nerve entrapment
a. Pathology: adductor muscle hypertrophy, resulting in chronic medial thigh pain
b. Nerve conduction studies can aid in diagnosis
c. Treatment: conservative, stretching
• Lateral femoral cutaneous nerve entrapment (“meralgia paresthetica”)
a. Presentation: pain and dysesthesia in the proximal lateral thigh; symptoms exacerbated with prolonged hip flexion and tight lap belts
b. Treatment: conservative, stretching
• Sciatic nerve entrapment
a. Pathology: occurs at the level of the ischial tuberosity or the piriformis (“piriformis syndrome”), causing pain in the buttocks and posterior thigh
b. Treatment: conservative, stretching; surgical release is rarely needed
E. Miscellaneous
1. Anterior superior iliac spine avulsion fractures
• Demographic: adolescent athletes secondary to sudden contractions of sartorius or tensor fascia lata
• Treatment: conservative, protected weight bearing
a. Surgery considered in painful nonunions and displacement > 3 cm
2. Quadriceps contusion
• Can result in intramuscular hemorrhage and carries a low risk of compartment syndrome
• Acute management requires icing and immobilization in flexion (120 degrees)
II. Knee
A. Anatomy (Fig. 8.5)
1. Femoral condyles, both convex (Fig. 8.6)
• Lateral: wider medial-lateral, projects more anteriorly
• Medial: larger/more curved, projects more distally/posteriorly
2. Tibia plateau, 7- to 10-degree posterior slope
• Medial: oval, larger, biconcave (Fig. 8.7)
• Lateral: circular, smaller, convex (sagittal)/concave (coronal)
3. Proximal tibia
• Tibial tubercle anterior, patellar tendon attachment
• Gerdy’s tubercle 2–3 cm lateral, insertion IT band
• Joint capsule 1.5 cm below joint line at posterior recesses
• Fixator pins should not be within 15 mm of the joint due to the risk of being intracapsular.
Fig. 8.5 Knee anatomy. (a) Anterior. (b) Posterior. (From Schuenke M, Schulte E. General Anatomy and the Musculoskeletal System: Thieme Atlas of Anatomy. New York: Thieme; 2005. Illustration by Karl Wesker.)
4. Proximal fibula
• Proximal tibiofibular articulation distal to knee joint
• Styloid process, attachment lateral knee stabilizers (Fig. 8.8)
a. Insertions from anterior to posterior: lateral collateral ligament (LCL), popliteofibular ligament, biceps tendon
5. Patella, largest sesamoid, thickest cartilage (5 mm midportion)
• Fulcrum to increase quadriceps strength, protective
• Bipartite patella (superolateral), differentiate from fracture
6. Patellofemoral stabilizers
• Conforming bony/cartilaginous anatomy (Fig. 8.9)
Fig. 8.6 Femoral condyle anatomy. (a) lateral view and (b) anteroposterior view. M refers to the dimensions of the medial condyle and L refers to the dimensions of lateral condyle.
Fig. 8.7 Differences in medial/lateral tibial plateau anatomy as demonstrated in axial view. (a) The medial plateau is larger, oval-shaped and biconcave. (b) The lateral plateau is smaller, circular and convex (sagittal)/concave (coronal).
Fig. 8.8 Origin/insertions of the lateral knee stabilizers. (Modified from Schuenke M, Schulte E. General Anatomy and the Musculoskeletal System: Thieme Atlas of Anatomy. New York: Thieme; 2005. Illustration by Karl Wesker.)
Fig. 8.9 Transverse section at the level of the patellofemoral joint. (From Schuenke M, Schulte E. General Anatomy and the Musculoskeletal System: Thieme Atlas of Anatomy. New York: Thieme; 2005. Illustration by Karl Wesker. Drawn from a specimen in the Anatomical Collection of Kiel University.)
• Retinaculum and extensor mechanism musculature
• Patellofemoral ligaments: medial patellofemoral ligament (MPFL) most important
• Medial patellofemoral ligament provides > 50% of total medial restraint to lateral patellar instability.
a. Origin: intersection of point just anterior to posterior femoral shaft and proximal to Blumensaat’s line (Fig. 8.10), just anterior and distal to adductor magnus insertion, between medial epicondyle and adductor tubercle
b. Inserts onto junction of upper and middle aspect of medial patella
7. Anterior cruciate ligament (ACL)
• Attachment/insertion, dimensions (Fig. 8.11)
• Bundles: anteromedial and posterolateral
• Anteromedial bundle tight in flexion; posterolateral bundle tight in extension
a. Anteromedial (AM): stronger, anterior tibial stability, tight in flexion
b. Posterolateral (PL): rotatory stability, tight in extension
◦ Isolated AM tear: increased anterior translation at 90 degrees’ flexion
◦ Isolated PL tear: increased anterior tibial translation and rotatory instability at 30 degrees’ knee flexion
• Native strength: 2,200 N (maximum tension in full knee extension)
8. Posterior cruciate ligament (PCL)
• Attachment/insertion, dimensions (Fig. 8.12)
• Bundles: anterolateral and posteromedial
• Bundles are opposite those of the ACL.
Fig. 8.10 (a) Depiction of medial patellofemoral ligament (MPFL) insertion at the intersection of a point just anterior to the posterior femoral shaft and proximal to Blumensaat’s line. (b) Other relevant anatomy of the medial knee. aMCL, anterior medial collateral ligament. AMT, adductor magnus tendon; AT, adductor tubercle; GT, gastrocnemius tubercle; MCL, medial collateral ligament; ME. medial epicondyle; MGT, medial gastrocnemius tendon; POL, posterior oblique ligament.
Fig. 8.11 (a,b) Anterior cruciate ligament anatomy: footprint dimensions and bundle origins/insertions. AM, anteromedial; PL, posterolateral.
Fig. 8.12 (a,b) Posterior cruciate ligament (PCL) anatomy: footprint dimensions and bundle origins/insertions. AL, anterolateral; PM, posteromedial.
b. Posteromedial (PM): rotatory stability
• Strength: 2,500–3,000 N
9. Common ACL/PCL characteristics
• Anterior bundles: tight in flexion; posterior bundles: tight in extension
• Both secondary stabilizers to knee varus/valgus stress
• Composition: 90% type I, 10% type III collagen
• Vascular supply: primarily middle genicular artery
• Innervation: tibial (sciatic) nerve (posterior articular branch)
10. Medial stabilizers (Fig. 8.13 and Table 8.3)
Fig. 8.13 Medial and lateral posterior knee stabilizers. (From Schuenke M, Schulte E. General Anatomy and the Musculoskeletal System: Thieme Atlas of Anatomy. New York: Thieme; 2005. Illustration by Karl Wesker.)
Table 8.3 Medial Knee Layers/Dynamic Stabilizers
Medial layer |
|
I | Sartorial/vastus medialis fascia |
II | Superficial MCL, posterior oblique ligament, semimembranosus, MPFL |
III | Deep MCL and capsule |
Dynamic stabilizers | Semimembranosus, gracilis, semitendinosus, sartorius, vastus medialis |
PMC | Posterior oblique ligament (originates from adductor tubercle), oblique popliteal ligament (posterior capsular thickening, continuous with deep MCL), semimembranosus (multiple tendinous insertions) |
Abbreviations: MCL, medial collateral ligament; MPFL: medial patellofemoral ligament; PMC, posteromedial corner.
• Three anatomic layers of medial knee; static and dynamic stabilizer of medial collateral ligament (MCL)
a. Superficial MCL: vertical sheet, deep to pes anserinus that originates 3 mm proximal and 5 mm posterior to medial femoral epicondyle; inserts distal to joint line (4–6 cm)
◦ Primary function valgus stability; anterior portion tight in flexion, posterior tight in extension
b. Deep MCL: capsular thickening with meniscofemoral and meniscotibial components
• Posteromedial corner (PMC) components (Table 8.3)
a. Function: internal knee rotatory stability
11. Lateral stabilizers (Fig. 8.13 and Table 8.4)
• Lateral (or fibular) collateral ligament (LCL)
a. Cord like structure; 3–4 mm in diameter, 6 cm in length
b. Varus knee stabilizer; isolate at 30 degrees’ flexion; also secondary anterior-posterior stabilizer (along with MCL)
• Other lateral stabilizers (Fig. 8.8)
a. Three anatomic layers of lateral knee; static and dynamic stabilizers
b. Popliteus: internal rotator of tibia
◦ Originates posterior tibia; inserts anterior, inferior, and deep to LCL origin
◦ Intra-articular segment passes through popliteal hiatus (posterolateral aspect of lateral meniscus)
◦ Popliteofibular ligament branches off popliteus
Table 8.4 Lateral Knee Layers/Dynamic Stabilizers
Lateral layer |
|
I | Iliotibial band, long head biceps femoris, fascia |
II | Lateral patellar retinaculum/patellofemoral ligament |
III | LCL, fabellofibular ligament, arcuate/coronary ligaments, popliteus tendon/popliteofibular ligament, capsule |
Dynamic stabilizers | Long head biceps, popliteus, iliotibial band, lateral gastrocnemius |
PLC components | Popliteus/popliteofibular ligament, long head biceps femoris, lateral capsule, iliotibial band, fabellofibular ligament, arcuate ligament |
Abbreviations: LCL, medial collateral ligament; PLC, posterior lateral corner.
• Posterolateral corner (PLC) components (Table 8.4)
a. Function: external knee rotatory stability
12. Menisci
• Crescents, triangularly shaped in cross section
• Connected anteriorly via intermeniscal ligament, peripherally by coronary ligaments
• Variably present meniscofemoral ligaments (MFLs), 70%
a. Ligament of Humphrey (anterior to PCL), ligament of Wrisberg (posterior to PCL), originate on posterior horn, insert into medial femoral condyle/PCL
• Meniscal fiber types (circumferential, radial, and oblique)
a. Circumferential most abundant, dissipates hoop stress
b. Fibrocartilaginous material, primarily type I collagen
• Vascular supply (genicular arteries)
a. Peripheral third well-vascularized (red zone), middle third relatively avascular (red-white zone), inner third nonvascular (white zone; nourishment by diffusion) (Fig. 8.14)
◦ Posterior horns fed by middle genicular artery
◦ Posterolateral meniscus at the popliteal hiatus has minimal to no vascular supply
