a fall on an outstretched thumb with hyperabduction
at the MCP joint. Patients present with tenderness and
swelling over the ulnar aspect of the thumb MCP joint
with instability of the UCL on radial stress. Instability
should be assessed with the MCP in 30°of flexion and
at full extension. This can also be documented and
quantified on stress radiographs (Morgan and
Slowman, 2001; Abrahamson et al, 1990; Leddy,
1998; Rettig, 1992).- The injury may be associated with the Stener lesion, in
which the torn end of the UCL is displaced superficially
to the aponeurosis of the adductor pollicus, preventing
primary healing. Gross instability or a palpable lump
suggests a Stener lesion, which can sometimes also be
directly visualized with ultrasound or MRI. This lesion
may be present in up to 70% of cases (Morgan and
Slowman, 2001; Kahler and McCue, 1992). - Many injuries will do well with immobilization for 4
weeks in a thumb spica cast, followed by 2–4 months
of protected splinting during athletic competition.
•Surgical intervention with reattachment of the UCL is
typically required for any injury with greater than
30–35° of instability in flexion, any instability in
extension, a Stener lesion, or large bony avulsion
(Morgan and Slowman, 2001; Kahler and McCue,
1992; Abrahamson et al, 1990; Leddy, 1998).
RADIAL COLLATERAL LIGAMENT INJURY
- Radial collateral ligament injury may involve proxi-
mal or distal ligament tears of the ligament. - It is much less common than UCL injury but evalu-
ated and treated in a similar manner. Injuries may be
associated with volar subluxation of the joint and may
require surgical stabilization (Rettig, Coyle, and Hunt,
2002; Kahler and McCue, 1992).
TENDON INJURIES
MALLET FINGER
- This injury is also known as drop fingeror baseball
fingerand most commonly occurs in football receivers,
baseball players, and basketball players. Mallet finger
refers to a disruption of the extensor mechanism inser-
tion into the distal phalanx, resulting from forced flex-
ion of an actively extended DIP joint. A variably sized
piece of bone may be avulsed with tendon (Rettig,
Coyle, and Hunt, 2002; Leddy, 1998; Rettig, 1992). - The patient will have a passively flexed DIP joint with
full passive range of motion but inability to actively
extend at the DIP joint (Idler et al, 1990a).- Preferred treatment is continuous extension splinting
of the DIP joint for at least 6 weeks while allowing
PIP motion, then up to 4 weeks of nighttime splinting.
If there is a large bony fragment avulsed, some rec-
ommend surgical fixation with reduction and pinning.
Surgical treatment may be necessary for late, chronic
cases (Rettig, Coyle, and Hunt, 2002; Leddy, 1998;
Rettig, 1992; Aronowitz and Leddy, 1998).
- Preferred treatment is continuous extension splinting
BOUTONNIÈRE DEFORMITY- This injury is also known as a buttonholedeformity and
involves rupture or avulsion of the extensor mechanism
central slip at the middle phalanx. The head of the pha-
lanx may buttonhole through the defect. The lateral
bands then contract, causing late extension deformity at
the DIP joint (usually appearing 1–3 weeks later)
(Rettig, Coyle, and Hunt, 2002; Leddy, 1998). - This injury occurs with unrecognized palmer disloca-
tion of the PIP joint, or more commonly, by forced
flexion of the middle phalanx while the athlete is
attempting to extend the joint. The patient will present
with swelling and pain over the dorsal PIP joint,
inability to extend the PIP, and possible hyperexten-
sion at the DIP joint (Rettig, 1992).
•Treatment consists of extension splinting of the PIP
for 6 weeks, allowing DIP motion, followed by grad-
ual PIP motion. Chronic cases usually respond to
closed treatment as well. Cases associated with large
bony fragments should be surgically addressed
(Rettig, Coyle, and Hunt, 2002; Leddy, 1998; Rettig,
1992).
PSEUDOBOUTONNIÈRE DEFORMITY- This injury has a similar clinical appearance to the
Boutonnière deformity but a distinctly different
mechanism and treatment. It is caused by a hyperex-
tension injury to the DIP joint, disrupting the volar
plate and either the radial or ulnar collateral liga-
ment. Tissue contraction causes later development of
progressive PIP flexion deformity. Differentiation
from a Boutonnière deformity is possible by absence
of tenderness over the PIP central slip and equivalent
active and passive ranges of motion at the PIP joint
in this injury (Kahler and McCue, 1992; Leddy,
1998).
•Treatment is difficult and often prolonged, with
splinting recommended if PIP deformity is less than
45 °. Surgical intervention with capsular release is
often necessary for greater deformities (Leddy,
1998).
308 SECTION 4 • MUSCULOSKELETAL PROBLEMS IN THE ATHLETE