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8 Sports Medicine oftheHip andKnee
Fig. 8.7 Coronal MRI of the knee demonstrating medial
meniscus deciency after an ACL reconstruction. On the
left-hand side of the image, the triangle-shaped lateral
meniscus (blue arrow) is present. On the right-hand side of
the image, the medial meniscus is missing a signicant
portion (red arrow) due to a combination of chronic meniscal degeneration and prior surgery (partial meniscectomy)
tial to heal after being torn. The middle third of
the meniscus (red-white zone) is partially vascularized and has intermediate healing potential.
The central third of the meniscus (white-white
zone) is avascular and has poor healing potential.
In general, tears in the white-white zone are
debrided, while tears in the red-red zone are
repaired. It is important to preserve as much
functional meniscus tissue as possible when
debriding meniscal tears, as complete meniscectomy will lead to accelerated osteoarthritis.
Evaluation ofCommon Sports
Medicine Injuries
The principles involved in the initial evaluation
of the injured athlete focus on history and a
focused physical examination. Oftentimes injuries to the athlete are seen in real time which
helps better understand the mechanism of injury
and narrows the differential diagnosis For example, a football player who gets tackled from the
193
III II I
Fig. 8.8 Depiction of the vascular zones of the meniscus.
The right-hand side of the image demonstrates the periphery of the meniscus with the highest vascularity and best
propensity to heal after injury (zone I or the red–red zone).
The central segment has an intermediate vascular supply
and intermediate propensity to heal after injury (zone II or
the red–white zone). The left-hand side of the image demonstrates the central portion of the meniscus with the least
vascularity and lowest propensity to heal after injury
(zone III or the white–white zone). (Published with permission from Springer Publishing from Balke, M.,
Almqvist, K.F., Vansintjan, P., Verdonk, R., Verdonk, P.,
Hoeher, J. (2016). Traumatic Lesions in a Stable Knee:
Masterly Neglect—Meniscectomy—Repair. In: Hulet, C.,
Pereira, H., Peretti, G., Denti, M. (eds) Surgery of the
Meniscus. Springer, Berlin, Heidelberg)
side and sustains a valgus blow to the knee would
likely have an MCL injury, whereas a player who
is cutting or pivoting and feels a pop in their knee
without contacting another player would be more
likely to have an ACL tear. The on-eld sports
medicine physician also has a “golden window”
of time to evaluate the injury before the effects of
swelling, pain, and muscle spasm complicate the
physical exam. Additionally, signicantly displaced fractures or joint dislocations may be
more easily reduced in this immediate post-injury
setting while still on the eld. The sports medicine physician is frequently asked about the
safety of a player returning to play after specic
injuries. The return-to-play decision is based on a
variety of factors including the type and severity
of injury, as well as the nature of the sport and the
player’s position in that sport. Knowledge of the
common injuries, as well as the sporting activi-
194
W. F. Postma and N. Apselo
ties themselves, is important in making these
decisions. The following sections will focus on
the history as well as physical exam in the sports
medicine setting. Specics regarding the injuries
are elaborated on in their respective chapters.
History
The history in many sporting injuries is straightforward and related to acute trauma. Examples
include twisting the ankle when coming down for
a rebound, feeling the shoulder “pop out” when
being tackled, or hearing a “pop” within one’s
knee on cutting cross-eld. Important in this history is the mechanism of injury, as this often
relates very closely with the structure injured.
With the history alone, the diagnosis can be made
or at least narrowed to a few potential diagnoses.
Thus, the history is just as important and oftentimes more important than the physical examination. In contrast to acute traumatic sporting
injuries, overuse injuries typically have no specic identiable mechanism of injury. Examples
can include plantar fasciitis, shin splints, and
patellar tendinitis. For these insidious conditions,
it is important to obtain the specics of recent
activity, including changes in activity level or
type of activities (number of miles run per week),
changes in shoe wear or other equipment, or
changes to the surface utilized (track to road, at
surface to hills, etc.). Other pertinent details
include whether this problem has occurred
before, and if so, how it happened, what type of
treatment was rendered, and what the outcome
was. Previous problems may alert the clinician to
a different treatment problem to prevent recurrence of the injury. Examples include the management of “rst time” as opposed to recurrent
shoulder dislocations.
Symptoms that occur with activity and
improve with rest are typical of overuse injuries.
Pain that awakens a patient from sleep usually
indicates more serious injury or an underlying
systemic disorder. Are there any specic activities that might cause symptoms? In the athlete
with intermittent knee symptoms, pain in the
anterior aspect of the knee that is worse with stair
climbing or with prolonged sitting suggests problems related to the patellofemoral joint.
Symptoms that occur predictably with cutting
and pivoting activities, accompanied by swelling
and instability, suggest an internal derangement
of the knee such as a meniscus injury or tear of
the anterior cruciate ligament.
Physical Examination
The specic examination depends on the nature
of the symptoms and the region affected. Each
anatomic region and orthopedic condition has
pertinent special tests. All physical examinations,
however, should begin with inspection and observation of the extremity. After acute injury, one
should compare the injured limb in question to its
opposite side. Inspection for skin changes such as
ecchymoses, abrasions, and associated swelling
should be performed. Determining range of
motion of the joint in question, both actively and
passively, is imperative. First, have the athlete
move the joint in question and observe for associated pain or asymmetry as compared to the opposite side. Examples include a patient who presents
with shoulder pain of insidious onset whose
active and passive range of motion is asymmetric
and limited on the affected side, suggesting an
adhesive capsulitis as a diagnosis. This is compared to a rotator cuff injury where passive range
of motion would be full despite a limited active
range of motion. Other examples include the
inability to actively extend the knee after an acute
injury, despite nearly full passive range of motion.
This suggests an injury (rupture) of the extensor
mechanism that can be seen in patellar tendon or
quadriceps tendon ruptures, as well as some
patella fractures.
Strength assessment is an important component to the exam of any joint-related injury.
During strength assessment, weakness may be
due to direct injury to a musculotendinous unit
responsible for joint function. However, pain,
guarding, or reex inhibition of muscular contraction can also be responsible for perceived
weakness on examination. The ability of the
sports medicine professional to examine the ath-
8 Sports Medicine oftheHip andKnee
195
lete in the acute setting shortly after the injury
(before pain and swelling set in) is especially
helpful in obtaining an accurate assessment of
strength. Although relatively uncommon, injuries
to nerve and vascular structures can and do occur
and should be ruled out as a precipitating cause
of injury especially in the acute setting. Their
examination is an essential component of a complete physical exam.
On initial examination, one should always
keep an open mind for referred symptoms. In
addition to examining the joint in question, one
should also focus particularly on the adjacent
joints, as well as the spine, for a contributing role
in the symptoms. Examples include a slipped
capital femoral epiphysis (SCFE) of the hip in an
adolescent with knee pain or a cervical disc herniation as a cause for shoulder discomfort.
Applying special examination techniques specic to the area in question and suspected diagnosis completes the physical examination. These
techniques can be found in their respective chapters according to the area in question. Examples
of special tests include impingement signs in
case of shoulder pain or apprehension in the case
of shoulder instability as the arm is placed in a
position of abduction and external rotation.
Special Tests
Every joint has special tests associated with them
to aid in specic injuries. These are very important to diagnosis conrmation and are included to
a certain extent in the specic chapters and sections focused on those specic diagnoses.
X-Rays
Plain radiographs, or X-rays, are a useful tool in
the initial work-up of acute traumatic injuries
that occur in sports. X-rays are useful at identifying fractures of bones or dislocations of joints.
While soft tissue injuries may not demonstrate
any positive ndings on an X-ray, it is still
important to rule out fracture or dislocation as
causes of pain or swelling after an acute injury.
When X-rays remain negative but there is a high
suspicion for injury to an important structural or
functional soft tissue (e.g., anterior cruciate ligament, rotator cuff), then further advanced imaging can be obtained such as magnetic resonance
imaging (MRI), computed tomography (CT), or
ultrasound. Specically obtained radiographic
stress views can be useful in assessing joint
integrity. Common examples include stress
views taken for grade III injuries of the acromioclavicular (AC) joint or stress views of lateral
malleolus ankle fractures to assess for injury to
the syndesmosis.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is a useful
diagnostic imaging tool within sports medicine.
MRI provides for a high-resolution assessment
of soft tissues that cannot be visualized on X-ray
or CT.While X-ray and CT are the gold-standard
for evaluation of acute fractures, MRI is more
sensitive at identifying stress fractures.
Endurance athletes such as long-distance runners who report chronic bone or joint pain with
activity may have negative X-rays but ultimately
end up having an occult stress fracture that is
only seen on MRI.Common locations for stress
fractures in athletes include the tibia, navicular,
calcaneus, metatarsals, and femoral neck. The
addition of intra-articular contrast (MRI arthrogram) is especially helpful in the shoulder and
hip to aid in the diagnosis of labral tears. MRI
should be used judiciously as it is expensive
compared to plain radiographs, and it is common
to identify incidental age-related changes that
often do not need intervention. It is critical to
rst start with history and physical exam before
proceeding with MRI to further assess a suspected diagnosis.
Arthroscopy
Most commonly applied to the knee, shoulder,
ankle, elbow, and hip, arthroscopy is the goldstandard tool for denitive diagnosis and treatment of intra-articular injuries. Arthroscopy
involves the use of an “arthroscope,” which is a
minimally invasive tool comprised of a thin tube
with a video camera and light source which is
inserted into a joint through a small incision. The
joint is then insufated with uid to expand the
196
Fig. 8.9 Intraoperative picture taken during a knee
arthroscopy demonstrating a meniscal tear (outlined by
red bar). In this image, the broad white surface along the
bottom is the articular cartilage of the tibial plateau.
Above this lies the meniscus, which is ipped up with a
metal probe (right) to demonstrate an undersurface longitudinal meniscal tear
joint and allow for improved visualization and
insertion of tools (Fig.8.9). Its utility in diagnosis alone is not often utilized but can be especially helpful in situations where all other
diagnostic testing has not been successful in
establishing a diagnosis. The overwhelming use
of arthroscopy in the eld of sports medicine,
however, is for the treatment of joint injuries
once a diagnosis is reached (e.g., arthroscopically
assisted ACL reconstruction).
W. F. Postma and N. Apselo
Acute Traumatic Injuries
Immediate
Immediate treatment begins at the time of injury.
For acute traumatic injuries, it is often helpful to
provide some sort of immobilization to the
injured extremity to reduce pain and provide stabilization pending further imaging, if necessary.
An example of this would be placing a knee
immobilizer on a football player who gets tackled and feels a pop followed by immediate knee
pain. The mnemonic “RICE” (rest, ice, compression, elevation) is helpful in this immediate and
early period to minimize local soft tissue edema
and pain. If the sports medicine physician is present at a sporting event when an injury occurs,
then an immediate physical examination can be
performed to aid in forming a differential diagnosis and guide further management.
Early
Early treatment involves establishing a denitive
diagnosis and minimizing the sequelae of trauma,
including joint stiffness and muscle atrophy.
Additional testing is often required at this stage
to help formulate both the diagnosis and the
denitive treatment plan. An accurate diagnosis
at this stage is critical, as important time- sensitive
decisions need to be made (e.g., surgical versus
nonsurgical management, early range of motion
versus more prolonged immobilization, returnto- play timing). Nonsteroidal anti-inammatory
drugs (NSAIDs) are a useful tool to manage pain
and inammation during this period.
Treatment ofSports Injuries
Treatment of sports injuries follows an algorithmic approach. The goals of treatment are to initially reduce pain, inammation, swelling, and
stiffness, followed by increasing strength and
function to allow expeditious return to normal
function and athletic activity. Treatment varies
based on whether it is an acute traumatic injury
versus a chronic overuse injury. For acute traumatic injuries, treatment can be divided into
three distinct but overlapping phases: immediate, early, and late.
Late
The majority of sports injuries are successfully
treated without surgery. Physical therapy is often
necessary to allow patients to regain their preinjury strength and range of motion. This rehabilitation and recovery period can take weeks to
months depending on the injury. Specic indications for operative management vary depending
on the specic injury pattern, as well as the athlete’s goals and expectations both on and off the
athletic eld. Surgical intervention may involve
traditional open techniques, arthroscopic techniques, or a combination of both.
8 Sports Medicine oftheHip andKnee
197
Chronic Overuse Injuries
In the treatment of chronic overuse injuries, rest
is frequently employed in the form of activity
modication. In general, any activity that exacerbates symptoms should be avoided. The injured
tissues must be allowed to rest in order to heal
and resolve the inammatory process causing the
symptoms. Often for the athlete, this involves
temporary restriction from their sport.
During the period of activity modication, a
variety of techniques can be helpful to further
relieve pain and inammation in order to restore
normal function. This can begin with the use of
nonsteroidal anti-inammatory drugs (NSAIDs)
for symptom relief but not treating the underlying
problem in most cases. Various modalities such
as ice, heat, electrical stimulation, ultrasound,
and massage can all be helpful in decreasing pain
and swelling.
Although activity modication is the mainstay
of treatment, a prolonged period of inactivity can
result in muscular atrophy, joint stiffness, and
overall de-conditioning. Denitive treatment for
these injuries often involves a dedicated physical
therapy program aimed at restoring the athlete’s
strength and endurance required for a return to
sport. Focus on the athlete’s biomechanics is also
an essential component in treating overuse injuries to prevent recurrence. Attention to the specifics of the supporting structures is often helpful in
this regard. Alignment problems are often identied in this phase of treatment for lower extremity
injuries. Fabrication of a shoe lift orthotic for a
previously unrecognized limb length discrepancy
or a medial longitudinal arch support for overpronation can lead to a more successful return to
activity. Sometimes video analysis of the activity
is helpful to identify, correct, and prevent
improper biomechanics.
Occasionally, overuse injuries do not respond
to non-operative measures and surgical correction is required. Conditions that are occasionally
associated with failure of conservative treatment
include lateral epicondylitis (“tennis elbow”),
shoulder impingement, and patellar/Achilles tendonitis. Conservative treatment is trialed for prolonged periods—often 6months to 1year—before
resorting to surgical intervention. Rarely, stress
fractures in high-risk areas (e.g., femoral neck) or
those which fail to respond to adequate immobilization will require surgical intervention.
Common Pathologies Treated by Sports Medicine Specialists
Hip: Femoroacetabular Impingement (FAI)
The hip is a ball-and-socket synovial joint where
the ball (femoral head) articulates with the cup
(acetabulum). In individuals with normal anatomy, the femoral head is spherical and the acetabulum is hemispherical. In a disease process
known as femoroacetabular impingement (FAI),
commonly referred to as “hip impingement,” the
femoral head and/or acetabulum has a shape that
does not match each other, resulting in structural
impingement.
Bony overgrowth at the femoral head–neck
junction is referred to as a “cam lesion,” resulting
in cam impingement. Cam lesions are most commonly located at the anterosuperior aspect of the
femoral head–neck junction and are more commonly seen in males. With hip exion, adduction,
and internal rotation (the so-called FADIR
maneuver), the cam lesion impinges on the acetabular labrum, causing pain, labral tearing, and
in severe cases leads to articular cartilage delamination. With repeated injury to the articular cartilage over time, severe FAI can lead to osteoarthritis
of the hip.
Bony overgrowth of the acetabular rim is
referred to as a “pincer lesion” resulting in pincer
impingement. This so-called acetabular overcoverage can be focal or global. Pincer lesions
are most commonly located over the anterior or
anterosuperior acetabular rim. When the hip is
brought into FADIR, the pincer lesion on the
acetabulum impinges on the femoral neck. Mixed
lesions refer to the presence of both cam and pincer morphologies.
Patients typically present with insidious anterior or anterolateral hip pain although acute injuries can occur. Pain occurs with activity,
198
W. F. Postma and N. Apselo
especially exion activities such as squats and
lunges although sitting pain is commonplace as
the problem progresses as that position often
brings the impinging surfaces together, thus compressing or stressing the labrum and underlying
tear. The workhorse of the special test is the
FADIR test maneuver for that reason as well.
Initial evaluation of FAI includes radiographs
of the involved hip and pelvis (Fig.8.10). Specic
radiographs for FAI include an AP view of the
pelvis, frog-leg lateral view (hip abducted 45°),
Dunn lateral view (hip exed 90° and abducted
20°), modied Dunn lateral view (hip exed 45°
and abducted 20°), cross-table lateral view, and
false prole view (pelvis rotated 60° toward the
side being imaged). The Dunn and frog-leg lateral views are helpful in detecting femoral head–
neck asphericity (cam lesions), while the
cross-table lateral and false prole views are
helpful for evaluating acetabular over-coverage
(pincer lesions). The classic nding on an AP pelvis view of a severe cam lesion is called a “pistol
grip deformity.” Magnetic resonance imaging
(MRI) of the hip may be obtained to evaluate the
labrum and articular cartilage (Fig.8.11).
The initial treatment for patients with FAI is
conservative, starting with activity modication
and physical therapy. For patients who fail con-
servative treatment, the rst-line surgical treatment is hip arthroscopy with specic procedures
performed to address the patient’s specic pathology. Through an arthroscopic approach, cam and
pincer lesions can be resected, and the labrum
can be repaired, debrided, or reconstructed with
allograft. Hip arthroscopy has made it possible to
treat FAI through a minimally invasive approach.
Prior to hip arthroscopy, the treatment involved
open surgical hip dislocation (which is still
required in some severe cases). For patients with
end-stage osteoarthritis as a result of FAI, the
treatment is total hip arthroplasty.
Knee: Anterior Cruciate Ligament (ACL) Injury
The ACL is an intra-articular ligament in the
knee that spans from the medial wall of the lateral femoral condyle to the middle of the intercondylar area of the tibial plateau. The ACL
prevents anterior translation and rotation of the
tibia relative the femur. There are two distinct
bundles of the ACL. The anteromedial (AM)
bundle is tight in knee exion and primarily
resists anterior translation of the tibia relative to
the femur. In contrast, the posterolateral (PL)
Fig. 8.10 Left: AP pelvis X-ray. Right: Modied Dunn
lateral X-ray of the left hip. The left hip in the images
above demonstrates a cam lesion. The cam lesion (red
arrow) is more evident on the modied Dunn lateral view,
as this hip positioning places the lesion located along the
anterosuperior femoral head–neck junction perpendicular
to the X-ray beam
8 Sports Medicine oftheHip andKnee
Fig. 8.11 Coronal MRI arthrogram demonstrating hip
labral tearing (red arrow) in the setting of femoroacetabular impingement
199
Fig. 8.12 Coronal MRI of the knee demonstrating the
bone bruise pattern (white areas in the bone denoted by
the arrows) seen after anterior cruciate ligament (ACL)
injury. On T2 MRI, there is hyperintensity (indicative of a
bone bruise) along the lateral femoral condyle and posterior aspect of the lateral tibial plateau
bundle is tight in knee extension and primarily
resists rotation of the tibia relative to the femur.
ACL tears most commonly occur due to a
non-contact pivoting injury (e.g., when an athlete
plants their foot and twists to change direction).
The ACL receives blood supply from branches of
the middle geniculate artery. When the ACL is
torn, this blood supply is disrupted leading to
hemarthrosis or blood inside of the knee joint.
Intra-articular ligament injuries (e.g., ACL and
PCL) lead to hemarthrosis due to their presence
inside of the joint, whereas extra-articular injuries (e.g., MCL, LCL) bleed outside of the knee
joint capsule and do not form hemarthrosis.
On physical examination, the most sensitive
test to detect an ACL tear is the Lachman test,
while the most specic test is the pivot shift test.
The Lachman test is performed by positioning
the patient supine with the involved knee exed
to 20–30°. The examiner stabilizes the femur,
grasps the tibia, and attempts to translate the tibia
anteriorly relative to the femur. A positive
Lachman test is indicated by increased anterior
tibial translation compared to the contralateral
uninjured side. A positive Lachman test can be
graded according to severity with grade 1 being
3–5mm anterior translation of the tibia, grade 2
being 5–10 mm translation, and grade 3 being
>10mm translation.
The pivot shift test is performed with the
patient supine and the examiner initially holding
the involved extremity with the knee in extension. A valgus force and axial load are applied to
the knee along with slight internal rotation of the
tibia, leaving the tibia in an internally subluxated
position in the setting of ACL injury. The knee is
then slowly brought into exion. A positive pivot
shift is denoted by a palpable clunk or shift in the
knee which occurs around 30–40° exion, corresponding to the subluxated lateral tibial plateau
reducing onto the lateral femoral condyle. This
reduction and shift occur at roughly 30–40° knee
exion. The mechanism behind this shift is not
fully understood but may be partially due to the
iliotibial (IT) band transitioning from a knee
extensor to a knee exor as the knee goes from a
fully extended to exed position.
On MRI of knees with a torn ACL, there is a
classic bone bruise pattern involving the midportion of the lateral femoral condyle and the posterior aspect of the lateral tibial plateau (Fig.8.12).
These bone bruises occur secondary to the lateral
femoral condyle impacting the lateral tibial pla-
200
Fig. 8.13 Sagittal MRI of the knee demonstrating anterior cruciate ligament (ACL) tear
teau during the pivot shift subluxation that occurs
at the time of ACL injury. MRI also serves to conrm the diagnosis of an ACL tear and identify
concomitant injuries around the knee (e.g., meniscal tears, collateral ligament tears) (Fig.8.13).
The gold-standard surgical treatment for ACL
tears is an ACL reconstruction with tendon graft.
The most common autograft sources are patellar
tendon (with bone plugs from the patella and
tibia, also known as a “bone–patellar tendon–
bone” graft), hamstring tendon (semitendinosus/
gracilis), and quadriceps tendon. Alternatively, a
variety of different allograft (cadaver) options are
available. The surgery is performed with
arthroscopic assistance, and the graft is passed
through tunnels drilled through the anatomic
footprints of the native ACL on the proximal tibia
and lateral femoral condyle. Postoperatively,
patients undergo functional physical rehabilitation with an emphasis on progressive range of
motion, strengthening, and agility with the goal
of returning to full sport roughly 9–12 months
after surgery.
W. F. Postma and N. Apselo
Shoulder
Sports medicine surgeons treat a variety of shoulder pathology, including glenohumeral instability
(shoulder subluxations and dislocations), labral
tears, and rotator cuff tears. For more detailed
information, see Chap. 9.
Summary andConclusion
Sports medicine has evolved to encompass care
of not only those participating in sports but of all
active individuals. As patients continue to remain
active into their older age, the sports medicine
physician’s role has expanded to include everyone from children on youth soccer teams to octogenarian pickleball players. The eld of sports
medicine has signicantly advanced over the past
several decades with continual innovation in
arthroscopic surgery techniques and rehabilitation protocols. As our knowledge of the basic science of musculoskeletal tissues advances, so do
our techniques for treating them when injured.
Patients are now able to return to sports and
activities after injury quicker and safer than
before.
Further Reading
1. Miller MD, Thompson SR. DeLee, Drez, & Miller’s
orthopaedic sports medicine: principles and practice.
5th ed. Philadelphia, PA: Elsevier; 2019.
2. Madden CC, Putukian M, McCarty EC, Young CC,
editors. Netter’s sports medicine. 3rd ed. Philadelphia,
PA: Elsevier; 2022.
3. Azar F.Orthopaedic knowledge update (OKU): sports
medicine 6. Rosemont, IL: American Academy of
Orthopaedic Surgeons; 2020.
4. Miller MD. Operative techniques in sports medicine
surgery. 3rd ed. Philadelphia, PA: Wolters Kluwer;
2021.
The Shoulder
EvanMichaelson andBrentWiesel
9
Functional Anatomy
The shoulder girdle includes three bones (scapula, clavicle, and proximal humerus) (Fig.9.1),
three joints (glenohumeral, acromioclavicular,
and sternoclavicular), an additional articulation
(scapulothoracic), and some 17 musculotendinous units. These individual elements function in
a synchronous and interdependent manner in
order to maximize the power and range of motion
of the shoulder girdle. The clavicle is the sole
bony link between the upper extremity and the
axial skeleton.
The Glenohumeral Joint
The glenohumeral (GH) joint is the articulation
of the proximal humeral epiphysis (ball) with the
glenoid fossa (socket) of the scapula. This joint
contributes to the majority of motion in the shoulder girdle. As only 20–30% of the humeral head
is in contact with the glenoid fossa at any point in
the shoulder’s arc of motion and the radius of
E. Michaelson · B. Wiesel (*)
Georgetown University School of Medicine,
Washington, DC, USA
MedStar Orthopedic Institue, MedStar Georgetown
University Hospital, Washington, DC, USA
e-mail: Brent.B.Wiesel@gunet.georgetown.edu
curvature of the glenoid is greater than that of the
humeral head, there is little inherent bony stability of the GH joint. The joint has often been compared to a golf ball sitting on a tee turned on its
side. As a result, the soft tissues surrounding the
joint are responsible for maintaining joint stability and congruity while still permitting the tremendous range of motion required of the GH
joint. These soft tissue stabilizers include the
joint capsule, glenohumeral ligaments, glenoid
labrum, long head of the biceps tendon, and the
rotator cuff musculature. The burden placed upon
these soft tissues leads to the majority of degenerative and traumatic conditions affecting the
shoulder girdle.
The Glenohumeral Ligaments
The capsule of the shoulder is a specialized structure that contains distinct thickenings referred to
as ligaments (Fig. 9.2). The glenohumeral ligaments are named for their origin from the glenoid
rim. This ligamentous complex includes the
superior glenohumeral ligament (SGHL), the
middle glenohumeral ligament (MGHL), and the
inferior glenohumeral ligament. These ligaments
function as static stabilizers of the glenohumeral
joint. The SGHL is the primary restraint to inferior translation and external rotation with the arm
in adduction. The MGHL is the primary stabilizer to anterior translation with the arm in 45° of
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024
W. F. Postma et al. (eds.), Essentials of Orthopedic Surgery,
https://doi.org/10.1007/978-3-031-66215-7_9
201
202
AC joint
E. Michaelson and B. Wiesel
Fig. 9.1 Anterior view
of the shoulder
demonstrates the
skeletal anatomy and
two of the four
articulations, the
glenohumeral and
acromioclavicular joints
Bicipital
groove
Greater
tubercle
Lesser
tubercle
Acromion
Deltoid
tuberosity
abduction. The inferior glenohumeral ligament
complex includes an anterior band (AIGHL),
posterior band (PIGHL), and an intervening sling
or pouch. The inferior glenohumeral ligament
complex becomes taut when the arm is abducted
to 90°. In this position, the anterior band resists
anterior translation with external rotation, and the
posterior band resists posterior translation with
internal rotation forces. The sling supports the
humeral head.
The Labrum
Distal
clavicle
Clavicle
Coracoid
Scapula
Glenoid
Glenohumeral
joint
more triangular shaped and well dened and the
inferior aspect of the labrum more rounded and
less distinct. Common anatomic variations
include a sublabral hole (foramen) or an absent
labrum in the anterior-superior quadrant of the
glenoid. The combination of a cord-like MGHL
and absent anterosuperior labrum has been
termed a Buford complex. It is important that the
surgeon recognize variations in labral anatomy as
inappropriate repair of a sublabral foramen or
Buford complex will lead to signicant postoperative stiffness.
The labrum is a brous structure of variable anatomy that attaches to the rim of the glenoid cartilage through a brocartilaginous zone, increasing
the depth of the glenoid concavity by 50%. The
labrum functions to increase the surface contact
area with the humeral head; to act as a static stabilizer through a buttress effect; and to serve as
an attachment site for the shoulder capsule, glenohumeral ligaments, and long head of the biceps
tendon. The labrum has a variable cross-sectional
anatomy, with the superior aspect of the labrum
The Rotator Interval
The rotator interval is the triangular region
between the superior aspect of the subscapularis tendon and the anterior aspect of the
supraspinatus tendon whose base is the coracoid. The rotator interval includes a number of
brous structures including the coracohumeral
ligament (CHL), the SGHL, and the transverse
humeral ligament. The coracohumeral ligament is the most signicant structure in the