Abstract
Background: Adductor dysfunction is a condition that can cause groin
pain in competitive athletes, but the source of the pain has not been
established and no specific interventions have been evaluated. We previously
defined a magnetic resonance imaging protocol to visualize adductor
enthesopathy. The aim of this study was to elucidate, in the context of
adductor-related groin pain in the competitive athlete, the role of the
adductor enthesis (origin), the relevance of adductor enthesopathy diagnosed
with magnetic resonance imaging, and the efficacy of entheseal pubic cleft
injections of local anesthetic and steroids.
Methods: We reviewed the findings in a consecutive series of
twenty-four competitive athletes who had presented to our sports medicine
clinic with groin pain secondary to adductor longus dysfunction. Magnetic
resonance imaging was performed to assess the adductor longus origin for the
presence or absence of enthesopathy. Seven patients (Group 1) had no evidence
of enthesopathy on magnetic resonance imaging, and seventeen patients (Group
2) had enthesopathy confirmed on magnetic resonance imaging. All patients were
treated with a single pubic cleft injection of local anesthetic and steroid
into the adductor enthesis. At one year after this treatment, the patients
were assessed for recurrence of symptoms.
Results: On clinical reassessment five minutes after the injection,
all twenty-four athletes reported resolution of the groin pain. At one year,
none of the seven patients in Group 1 had experienced a recurrence. Sixteen of
the seventeen patients in Group 2 had a recurrence of the symptoms (p <
0.001) at a mean of five weeks (range, one to sixteen weeks) after the
injection.
Conclusions: A single entheseal pubic cleft injection can be
expected to afford at least one year of relief of adductor-related groin pain
in a competitive athlete with normal findings on a magnetic resonance imaging
scan; however, it should be employed only as a diagnostic test or short-term
treatment for a competitive athlete with evidence of enthesopathy on magnetic
resonance imaging.
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors for a complete description of levels of evidence.
Groin pain in a competitive athlete (someone who participates in sports
four to seven days per week, has a coach, and competes against other athletes)
is a common and challenging entity. It is most prevalent in sports that
involve kicking and rapid changes of direction, such as football, ice hockey,
soccer, and Australian rules
football1-6.
Ek-strand and Hilding reported a prevalence of 8% in a study of 326 soccer
players followed over a one-year
period7.
The underlying etiology of groin pain is usually attributed to one of four
broad categories: adductor longus dysfunction, osteitis pubis, sports hernia
(also known as sportsman's hernia, pre-hernia complex, and Gilmore's groin),
and a pathological condition of the hip joint (femoroacetabular impingement
and disorders of the labrum, chondral surfaces, and capsular structures).
There is overlap between pathological conditions involving the hip joint and
groin8. There are no
universally agreed upon definitions or diagnostic criteria for the three
extra-articular causes of athletic groin pain (i.e., all except pathological
hip conditions). There appears to be a geographical/sports-specific variation
in diagnosis: in Europe, soccer players with groin pain are usually diagnosed
with adductor dysfunction or a
pre-hernia7,9,10,
whereas groin pain in athletes who play Australian rules football is typically
attributed to osteitis pubis or adductor
dysfunction2,5,11.
We believe that the literature on this subject has been limited by a lack
of standardization and uniformity with regard to assessment, definitions, and
diagnostic criteria. All patients presenting to our sports medicine clinic
with groin pain are assessed in a standardized manner. Specifically, all
undergo a physical examination of the groin and hips, and plain radiographs of
the hips are made. On the basis of this preliminary assessment, most patients
then undergo either a magnetic resonance arthrogram of the hip or a magnetic
resonance imaging scan of the groin, or both. Adductor dysfunction is
considered to be present if the physical examination demonstrates tenderness
at the adductor enthesis and pain on passive adductor stretching and resisted
adduction. Osteitis pubis is diagnosed if there is inflammation of the pubic
symphysis that manifests as a tender symphysis and can be seen on magnetic
resonance imaging. A sports hernia, which is essentially a clinical diagnosis
confirmed at surgery, is indicated by any combination of a torn external
oblique aponeurosis, a torn conjoined tendon, or dehiscence between the
conjoined tendon and the inguinal
ligament1-4
(Table I).
Of the four adductor muscles, the adductor longus is chiefly implicated in
groin pain in
athletes4,12.
However, the specific site and source of pain within the adductor longus has
not been established. Two potential sources are described in the literature:
the musculotendinous unit and the fibrocartilaginous insertion of the adductor
tendon on the pubic bone, termed the adductor
enthesis4.
The standard treatment for groin pain is nonoperative and consists of rest,
ice, nonsteroidal anti-inflammatory medications, and
physiotherapy2-4.
The treatment of osteitis pubis with pubic cleft injections of local
anesthetic and steroids directed into the pubic symphysis was first described
over a decade
ago13. The term
pubic cleft injection is employed widely in the literature, but there
is no universally agreed-on definition. We define it as any injection into the
groin or pubic region, with the pubic symphysis being one potential target. We
use the adjectives symphyseal (i.e., into the pubic symphysis) or
entheseal (i.e., into the adductor longus enthesis) to specify the
target of the injection. All injections given in this study were directed into
the adductor enthesis, and the term entheseal pubic cleft injection
shall be used to denote this.
Orthopaedic surgeons are well-accustomed to managing many insertional
tendon disorders such as tennis elbow, jumper's knee, and Achilles
tendinopathy; however, it is only fairly recently that researchers have
studied in depth the basic science of the sites where tendons and ligaments
meet
bone14,15.
Benjamin et al., pioneers in the field of the basic science of the enthesis,
recently discussed its structure and
function14,15.
Entheses are either fibrous or fibrocartilaginous according to their structure
and location; the adductor longus enthesis is
fibrocartilaginous15.
We believe that entheses are sites of stress concentration and hence prone
to injury, damage, and inflammation; a condition termed
enthesopathy14,15.
We also believe that enthesopathy often manifests clinically with the triad of
tenderness, pain on passive stretching of the affected muscle, and pain on
resisted muscle activation.
Previously, our group demonstrated the ability to visualize adductor longus
enthesopathy with use of a gadolinium-enhanced magnetic resonance imaging
protocol (Figs. 1-A and
1-B)16.
To our knowledge, no specific treatments for adductor longus dysfunction have
been evaluated or reported in the literature, and the treatment of adductor
longus dysfunction with entheseal pubic cleft injections (targeting the
adductor longus enthesis) has not previously been described. The aims of this
study were to identify the source of adductor-related groin pain in
competitive athletes and evaluate the roles of pubic cleft injections and
magnetic resonance imaging in diagnosis and treatment.
Between 1999 and 2000, twenty-four competitive athletes presented to our
sports medicine clinic with groin pain and were diagnosed with pure adductor
longus dysfunction. All patients presenting to the clinic with groin pain were
assessed in the same way, with use of the techniques for examination of the
groin described and validated by Hölmich et
al.17, a standard
hip examination, and plain anteroposterior and frog-leg radiographs of the
pelvis. Only patients with pure adductor longus dysfunction—i.e., no
clinical or radiographic evidence of pathological involvement of the hip joint
and no clinical evidence of a sports hernia or osteitis pubis—were
included in this study.
To be included in the study, a patient had to be a competitive athlete,
meet all three clinical criteria for the diagnosis of adductor dysfunction
(tenderness localized to the adductor longus origin, pain on passive
stretching of the adductors, and pain on adduction of the thigh against
resistance [Tables I and
II]), and have failed to
respond to a period of nonoperative treatment that included rest, ice,
nonsteroidal anti-inflammatory medications, and physiotherapy. Patients were
excluded if they exhibited clinical evidence of osteitis pubis or a sports
hernia or had evidence of pathological involvement of the hip joint clinically
or on plain radiographs or a magnetic resonance arthrogram.
All twenty-four athletes fulfilled the criteria and were diagnosed with
unilateral adductor dysfunction. At this point, they were enrolled
prospectively into the study. All patients were subsequently managed in the
same way, and none were lost to follow-up.
The patient population comprised eighteen professional soccer players, two
professional rugby players, two Olympic track-and-field athletes, one
semiprofessional soccer player, and one squash player. All patients were male,
and the mean age was 27.7 years (range, nineteen to forty-one years).
The pain was categorized as either acute (beginning immediately after a
discrete event) or gradual in onset and according to the 4-point functional
pain classification scale of Puffer and
Zachazewski18
(Table III).
All athletes had a magnetic resonance imaging scan within one week after
presentation to the clinic. The scans were performed with a Philips Intera
1.5-T system (Philips Medical Systems, Best, The Netherlands). Imaging was
performed according to our previously described
protocol16 and
included STIR (short tau inversion recovery) coronal, T1-weighted axial
oblique, and T1-weighted post-intravenous gadolinium fat-suppressed axial
oblique and sagittal sequences. The magnetic resonance imaging scan was
evaluated by a musculoskeletal radiologist (P.R. or P.J.O'C.) to determine the
presence or absence of adductor longus enthesopathy, which was defined as
abnormal enhancement of the adductor longus enthesis on the post-gadolinium
sequences. The radiologists were provided with full clinical details.
All twenty-four athletes then received a pubic cleft injection within one
week after presentation (following the magnetic resonance imaging scan). The
injection was performed under image intensification or ultrasound guidance.
The pubic hair was shaved, and the area was aseptically prepared. A 21-gauge
needle was inserted into the pubic cleft and directed toward the adductor
longus enthesis. The enthesis was located with use of ultrasound or with image
intensification to visualize the osseous landmarks—i.e., the angle
between the pubic crest and the pubic symphysis. The image intensification
technique relies on the surgeon integrating the image with tactile feedback
from the needle. The needle is first directed into the pubis and then moved a
few millimeters into the fibrocartilaginous enthesis, where the injection is
sited. If the needle is withdrawn too far laterally, a "give" is
felt as it encounters the lower resistance of the soft tissues. The injections
contained triamcinolone acetonide (80 mg in 2 mL) mixed with Marcaine
(bupivacaine) (3 mL of a 0.5% solution). Clinical reassessment was performed
five minutes after the injection. This again consisted of palpation over the
adductor longus insertion site, passive stretching of the adductors, and
performance of active adduction against resistance.
The athletes were then provided with a program of closed and open-chain
adductor strengthening and stretching exercises. They were advised to return
to full training one week following the injection, with no limitations or
precautions, as comfort allowed. The patients were seen in the clinic at six
weeks following the pubic cleft injection. At one year, they were sent a
questionnaire to evaluate their response to treatment.
Statistical Methods
The Fisher exact and Mann-Whitney U tests were used to compare the
characteristics of the two groups. P values of <0.05 were considered
significant.
All plain radiographs of the hip joint showed normal findings, with no
evidence of femoroacetabular impingement. On the basis of the magnetic
resonance imaging findings, we divided the athletes into two groups: Group 1
(seven patients) had no evidence of enthesopathy and Group 2 (seventeen
patients) had positive findings of enthesopathy.
All athletes in Group 1 were professional soccer players. Their ages ranged
from nineteen to thirty-four years (mean, 27.4 years). According to the
classification scale of Puffer and
Zachazewski18, six
athletes had type-2 pain and one athlete had type-3 pain. The mean duration of
symptoms was six weeks (range, four to eight weeks). All but one patient had a
gradual onset of symptoms.
Group 2 comprised eleven professional soccer players, one semiprofessional
soccer player, two professional rugby players, two track-and-field athletes,
and one squash player. Their ages ranged from nineteen to forty-one years
(mean, 28.3 years). Three athletes had type-2 pain, which had been present for
one to eighteen weeks (mean, twelve weeks). Eleven athletes had type-3 pain,
with a duration of six to fifty-two weeks (mean, twenty-seven weeks). Three
athletes had type-4 pain, with a duration of eight to forty weeks (mean,
twenty-one weeks). The onset was gradual in twelve athletes and acute in
five.
Activity-Related Symptoms
(Table IV)
Four of the seven athletes in Group 1 and nine of the seventeen athletes in
Group 2 had pain on kicking. However, all of the athletes in Group 1 were
professional soccer players, whereas five athletes in Group 2 were not soccer
players and thus did not engage in kicking. Of the twelve soccer players in
Group 2, nine experienced pain when kicking. All athletes in both groups had
pain on sprinting. No athlete had bilateral pain in Group 1, and nine of the
seventeen athletes had bilateral pain in Group 2.
Statistical Comparison of the Groups
There were significant differences between Group 1 and Group 2 with regard
to the duration of symptoms (mean and standard deviation, 6 ± 1.2 weeks
and 23.5 ± 16 weeks, respectively; p < 0.01) and the type of pain
recorded (more severe and often bilateral in Group 2; p < 0.01).
Post-Injection Results
Immediate (Five-Minute) Reassessment
All twenty-four athletes reported resolution of the pain when adductor
dysfunction was reassessed clinically at five minutes following the injection
of local anesthetic and steroids. All three tests for adductor dysfunction
were negative for all of the athletes at the five-minute reassessment.
Six-Week Follow-up Assessment
There were no complications as a result of the pubic cleft injections. At
six weeks after the injection, no athletes in Group 1 but eleven of the
seventeen patients in Group 2 reported a recurrence of symptoms.
One-Year Follow-up Assessment and Overall Results
Eight athletes, including all seven in Group 1, had a good result, with no
recurrence of symptoms, and were playing at the premorbid level, free of pain,
at the one-year follow-up assessment. Sixteen athletes, all in Group 2,
reported a transient response to the injection with recurrence of pain at an
average of 5.4 weeks (range, one to sixteen weeks) after the injection. There
was a significant difference in the rate of recurrence of pain between Group 1
(zero of seven) and Group 2 (sixteen of seventeen) (p < 0.001).
Apainful groin in a competitive athlete is a challenging, heterogeneous
entity. In the majority of cases, it is transient and successfully treated
with nonoperative means. At the other end of the spectrum, some athletes'
careers have been curtailed by a chronically painful groin. Historically, the
underlying etiology of pain in the groin has been attributed to one of four
broad categories: adductor longus dysfunction, osteitis pubis, sports hernia,
or a pathological condition of the hip
joint1-7,19.
We believe that adductor enthesopathy is a potential source of
adductor-related groin pain in competitive athletes. To our knowledge, no one
has explored the role of specific interventions in the treatment of
adductor-related groin pain and we are the first to evaluate the response to
entheseal pubic cleft injections of patients with adductor-related groin
pain.
In our clinic, we follow a clear protocol for the management of groin pain.
All patients in this study had adductor dysfunction with pain on palpation of
the adductor enthesis, passive adductor stretching, and resisted adduction. At
five minutes following an entheseal injection containing a local anesthetic,
all patients reported that the provocation maneuvers were no longer painful.
We believe that this finding supports our assertion that the enthesis is the
source of pain in these patients.
The majority of the patients in Group 1 had had a short duration of
symptoms (mean, six weeks) and type-2 pain before the injection, whereas in
Group 2 the mean duration of symptoms was longer (more than twenty-five weeks)
and the pain was predominantly type 3; these differences were both
significant. The differences in clinical symptoms appear to correlate with the
severity of the disease progression, the findings on magnetic resonance
imaging, and the response to the injection. Thus, patients with clinical
adductor dysfunction but no evidence of enthesopathy on magnetic resonance
imaging are postulated to have early, mild disease. This is usually reversible
and should respond to corticosteroid injection. However, those with evidence
of adductor enthesopathy on magnetic resonance imaging may have more advanced
disease, which may be resistant to treatment with corticosteroid
injection.
Entheseal injections can be expected to afford at least one year of pain
relief in patients who have had a short duration of symptoms, type-2 pain, and
no evidence of adductor enthesopathy on magnetic resonance imaging. However,
such injections should be employed only as short-term treatment for patients
with a long duration of symptoms, type-3 or 4 pain, and evidence of adductor
enthesopathy on magnetic resonance imaging.
We acknowledge that this study had limitations, but we believe that the
fact that the enrolled subjects were competitive athletes essentially
predetermined the study's methodology. A substantial limitation of the study
is the fact that the radiologists were provided with full clinical details
regarding the patients and therefore were not blinded. Ideally, a double-blind
randomized controlled trial (comparing pubic cleft injection with a control
group) with longer follow-up would have been undertaken. However, these
high-level athletes, for whom a trial of conventional nonoperative treatment
had already failed, were not suitable subjects for enrollment in such a study;
even one year represents a substantial proportion of a top-level athlete's
career. This study focused on a unique cohort of patients (competitive
athletes), and the conclusions that were reached are not necessarily
applicable to other groups (e.g., recreational athletes). The use of entheseal
pubic cleft injections in individuals who are not competitive athletes
requires further investigation. ?
Note: The authors acknowledge Phil McShane (Senior Medical
Statistician, Clinical Trials Research Unit, University of Leeds, England) and
Andy Scally (Department of Medical Statistics, University of Bradford,
England) for their assistance with the statistical analysis.
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