ArticlePDF AvailableLiterature Review

The acetabular rim syndrome. A clinical presentation of dysplasia of the hip


Abstract and Figures

The acetabular rim syndrome is a pathological entity which we illustrate by reference to 29 cases. The syndrome is a precursor of osteoarthritis of the hip secondary to acetabular dysplasia. The symptoms are pain and impaired function. All our cases were treated by operation which consisted in most instances of re-orientation of the acetabulum by peri-acetabular osteotomy and arthrotomy of the hip. In all cases, the limbus was found to be detached from the bony rim of the acetabulum. In several instances there was a separated bone fragment, or 'os acetabuli' as well. In acetabular dysplasia, the acetabular rim is subject to abnormal stress which may cause the limbus to rupture, and a fragment of bone to separate from the adjacent bone margin. Dysplastic acetabuli may be classified into two radiological types. In type I there is an incongruent shallow acetabulum. In type II the acetabulum is congruent but the coverage of the femoral head is deficient.
Content may be subject to copyright.
©1991 British Editorial Society ofBone and Joint Surgery
0301-620X/9l/3 139 $2.00
JBoneJoint Surg[Br] 1991 ; 73-B :423-9.
VOL. 73-B, No. 3, MAY 1991 423
From the Inselspital, Berne
The acetabular rim syndrome is a pathological entity which we illustrate by reference to 29 cases. The
syndrome is a precursor of osteoarthritis of the hip secondary to acetabular dysplasia. The symptoms are
pain and impaired function.
All our cases were treated by operation which consisted in most instances of re-orientation of the
acetabulum by peri-acetabular osteotomy and arthrotomy of the hip.
In all cases, the limbus was found to be detached from the bony rim of the acetabulum. In several
instances there was a separated bone fragment, or ‘os acetabuli’ as well.
In acetabular dysplasia, the acetabular rim is subject to abnormal stress which may cause the limbus to
rupture, and a fragment of bone to separate from the adjacent bone margin. Dysplastic acetabuli may be
classified into two radiological types. In type I there is an incongruent shallow acetabulum. In type II the
acetabulum is congruent but the coverage of the femoral head is deficient.
The term ‘hip dysplasia’ means an abnormality of shape
or size of the acetabulum or femoral head, or of their
proportions or alignment one to the other. Most often, it
is the acetabulum which is dysplastic and its dispropor-
tion with the femoral head gives rise to symptoms. We
will describe what we call the acetabular rim syndrome.
The nature of bone fragments about the acetabular
rim has long been a subject for discussion. Anatomists
have regarded these structures as remnants of secondary
centres of ossification and a normal part of development
of the acetabulum (Lilienthal 1909). They were described
first by Albinus in 1737 and later, in 1876, by Krause who
proposed the name ‘os acetabuli’. The fragments, which
are of varying sizes, can appear as early as six years of
age, and may disappear before 20 years (Perna 1922 ; de
Cuveland and Heuck 1957; Ponseti 1978). Persistence
after this age has been explained on the hypothesis of
‘hormonal disturbance’ (Freedman 1934).
Radiologists and clinicians have described the
K. Klaue, MD
C. W. Durnin, MD, Clinical Research Fellow
R. Ganz, MD, Professor of Orthopaedics
Department of Orthopaedic Surgery, Inselspital, CH-30l0 Berne,
Correspondence should be sent to Dr K. Klaue.
fragments as non-specific osteochondritis comparable
with Perthes’ disease of the femoral head (Kargus 1933).
Dysplasia of the acetabulum appearing at puberty has
been attributed to secondary ‘absorption’ of the bony
acetabulum (Niethard 1984). The appearance of frag-
ments at later ages and their persistence have been
observed following trauma (Waschulewski 1967 ; Caudle
and Crawford 1988), rickets (Fromme 1921), osteomye-
litis, tuberculosis, and osteochondritis dissecans (Ruhle
1921 ; Schinz 1922). Fragments have been ascribed to
overloading of the acetabular rim in a dysplastic joint
causing fracture and separation of a segment of the rim
(Fiedler 1951). They are sometimes associated with cysts
in the acetabular roof (Outland and Flood 1936). In a
study of 1 1 1 1 pelvic radiographs from an asymptomatic
population, bone fragments were found in 2% to 3%
(Arho 1940).
Tears of the limbus, with or without an associated
bony fragment, are known to occur after traumatic
dislocation of the hip (Paterson 1957; Dameron 1959;
Rashleigh-Belcher and Cannon 1986 ; Shea, Kalamchi
and Thompson 1986). Limbus tears occurring without a
history of injury have been described only recently
(Altenberg 1977 ; Currier and Fitzerald 1988) and there
has been no explanation of their cause or their relation to
acetabular dysplasia.
Limbus tears have been diagnosed by arthroscopy
(Suzuki et al 1986; Ikeda et al 1988), conventional
arthrography (Dorrell and Catterall 1986) and CT scan
Fig. I
Fig. 2 Fig. 3
(Paterson 1987). There are no previous descriptions of
the use of the computerised arthrotomography, nor of
magnetic resonance imaging as we employ them.
History. The presentation in all our cases was similar.
None were symptom-free. Most were young adults. They
complained of knife-sharp pain in the groin and a
sensation oflocking ofthe hip. These symptoms occurred
after a period of sitting, or sometimes after walking.
Some patients also described episodes of ‘giving way’
such as an inexplicable fall. Usually the pain could be
quickly relieved, often by shaking the limb, whereupon
normal walking could be resumed. Some activities which
predisposed to symptoms were rapid descent of stairs,
use of the breast-stroke when swimming, and sports such
as tennis or football. The common factor seemed to be
forced movements of adduction in combination with
rotation in either direction.
Questioning frequently discovered a long-forgotten
incident in which the hip had been stressed particularly
in rotation, causing sudden pain and the sensation of
‘dead leg’. Weight-bearing was painful and a period of
support with crutches had sometimes been necessary.
Two patients with these symptoms had undergone
inguinal or femoral herniorrhaphy ; another was sus-
pected of having entrapment of the lateral cutaneous
nerve of the thigh.
Clinical signs. Between painful episodes the affected hip
may be so normal to casual examination that an articular
origin for the pain may be doubted. When episodes of
locking occur frequently, residual pain may cause a slight
limp, possibly associated with weakness of the hip
abductors. However, in most cases pain can be elicited
by passive movement of the thigh into full flexion,
adduction and internal rotation (Fig. 1). This combina-
tion brings the proximal and anterior part of the femoral
neck into contact with the rim of the acetabulum
(Kapandji 1985), at exactly the point where the labrum
is likely to be damaged. The test exerts a shear force on
Clinical examination of the hip by passive flexion-
adduction-internal rotation. A sudden sharp pain is
elicited in the groin.
the limbus at its attachment to the acetabular bony
margin and if a tear is present, the dislocation of the
limbus may be palpable. Sometimes the opposite move-
ments, passive hyperextension with external rotation,
may also produce pain and a sensation of apprehension.
Imaging. It is not always possible to confirm the clinical
diagnosis of alabrum tear by imaging. A well-centred
anteroposterior radiograph, or the ‘faux-profil’ view of
Lequesne and de Seze (1961) may demonstrate a
congruent but short acetabular roof and an os acetabuli
(Fig. 2). On either of these views the radius of the
acetabulum may be seen to be greater than that of the
Figure 2 -Radiograph to show a well centred
femoral head. The acetabular rim has a loose
fragment (arrow) and the weight-bearing area
is therefore reduced. Figure 3 -Radiograph to
show incongruency between the femoral head
and the acetabulum. No free bony fragment is
visible in this instance.
Fig. 4
Fig. 5..r::i
.1. .r.
-‘- ,22’i3.88 .
VOL. 73-B, No. 3, MAY 1991
Right hip seen from the front. The limbus is detached from the bony
rim over one-fifth of its circumference.
CT scans. Figure 5a -Cysts in the anterior wall of the acetabulum
communicate both with the joint space and with a cyst on the anterior
quadrant of the capsule. Figure Sb -6 mm below the first cut, there is a
free fragment at the anterosuperior rim of the acetabulum. Operation
revealed an extra-osseous ganglion, communicating with an intra-
osseous cyst. The acetabular labrum was found to be detached at the
same site.
femoral head (Fig. 3). On the lateral view the anterior
centre-edge angle ofLequesne and de Seze (1961) and on
the anteroposterior view the lateral centre-edge angle of
Wiberg (1939) are reduced. Often the femoral head has
migrated laterally or anteriorly or in both directions, so
distorting the normal spherical shape of the acetabular
mouth into an oval.
In the few cases which we have investigated by
conventional arthrography and computerised arthroto-
mography we have been unable to demonstrate unequi-
vocally any tears of the limbus attachment, though we
were able to show hypertrophy, displacement and
truncation of the edge of the structure. Our own three-
dimensional adaptation oforthodox CT scanning (Klaue,
Wallin and Ganz 1988) allows a very accurate quantifi-
cation of the acetabular cover for the femoral head which
is not obtainable by conventional radiography. In six
cases this examination revealed the presence of cysts in
the soft tissues or intra-osseous ganglia at the edge of the
acetabular roof. In one case magnetic resonance imaging
suggested a limbus tear, which was confirmed at
Arthroscopy may permit visualisation of the limbus
but is difficult to perform and we have not used it.
Operative findings. In all our cases, the diagnosis of a torn
limbus made clinically was confirmed at operation. The
lesion was situated at the anterosuperior quadrant of the
acetabular rim and resembled a bucket-handle tear of a
knee meniscus. A hook could be passed between the body
of the limbus and the bone edge (Fig. 4).
Intra-osseous ganglia demonstrated by CT scans
(Fig. 5) were detectable from within the joint by use of
the same hook. These ganglia had a membranous lining
similar to that found in other intra-osseous ganglia.
Extra-osseous ganglia, when present, extruded from the
joint through the defect in the limbus to emerge on the
surface of the capsular structures, extending as much as
8 cm proximally.
Os acetabuli were easily identified. On their wider
surfaces we found true articular cartilage.
Treatment. In all our patients the primary problem was
deficiency of acetabular cover over the femoral head : the
principle of surgical management was to improve this by
re-orientating the acetabulum by means of a pen-
acetabular osteotomy (Ganz et al 1988, Fig. 6). In 12
Improved cover of the femoral head obtained by pen-
acetabular osteotomy. Re-orientation of the acetabulum
was achieved in three planes.
cases the tear in the limbus was repaired ; in 12 others the
torn limbus was resected ; in the remaining five the tear
wasjudged too small to need specific treatment.
Since our follow-up does not exceed four years it is
not yet possible to recommend a definitive management,
save to say that the slowest recovery was seen in those
cases in which the tear was repaired. Two of these
required revision to resect a re-ruptured limbus. In these
patients, and in those in whom the limbus was resected
primarily or left undisturbed the symptoms have all been
Tables I, II an III summanise the clinical and radio-
graphic findings. The five hips in which there was
radiological evidence of degenerative change have been
excluded, because their radiographic measurements had
become unreliable. We still consider these cases to be
part of the series, since the history, examination, and
surgical findings confirm a common cause.
The data show that all cases with lesions of the
acetabular rim had reduced acetabular cover of the
femoral head. Bone lesions occurred most frequently in
hips which were congruent, that is those in which the
acetabular and femoral head centres closely corresponded
(Fig. 7). Soft-tissue lesions, not radiologically visible,
Spercentage cover of the femoral head assessed by computerised graphical
te lat, distance from tear-drop to femoral head ;rf/ra, radius of the femoral
head divided by radius of the acetabulum, x 100 assessed on the
anteropostenior radiograph ;Cf-ca, distance between the centre of the
femoral head and the centre of the acetabulum, assessed on the anteropos-
tenor radiograph
Table II. Radiological results for 10 hips with bony
lesions of the acetabulum (six had one or more intra-
osseous ganglia; nine had a bony fragment at the
acetabular rim, four of them with an intra-osseous
Cf-ca (mm)
S Table I
Fig. 7
Table III. Radiological results for 14 hips with no
bony lesions visible on the acetabulum (all had a
limbus lesion, four with a soft-tissue ganglion)
Schematic diagram of the measurements employed to
estimate joint congruency and migration of the femoral
Rf-ra is the difference in length between the femoral head
radius and the acetabulan radius.
Cf-ca is the distance between the centres of femoral head
and acetabulum (this method is also valuable on the ‘faux
profil’ image).
e lat is the distance between the vertical lateral plane of
the ‘tear drop’ and the medial vertical tangential line
touching the femoral head.
Table I. Radiographical results for 24 hips with no degenerative
Measurement Mean ±SD Normal Source
Cover5 (per cent) 48 ± 2 70 Klaue et al
(degrees) 6 ±3 >25 Wiberg 1939
Anterior CE angle
(degrees) -1 ± 4 >20 Lequesne and
de Seze 1961
(degrees) 23 ± 2 <10 T#{246}nnis1984
elat(mm)t 11.5±1
rf/ra (per cent)t 76 ± 3
Cf-ca(mm)t 7.5±1
Measurement Mean ± SE Normal
Cover (per cent) 50 ± 2 70
Lateral CE angle (degrees) I 1 ± 3 >25
Anterior CE angle (degrees) 4 ± 4 >20
Roofangle (degrees) 17.5 ± 2 <10
elat(mm) 11.1±1
rf/ra (percent) 85 ±3
Measurements Mean ± SE Normal
Cover(percent) 47 ±2 70
Lateral CE angle (degrees) 2 ± 5 >25
Anterior CE angle (degrees) -5 ± 5 >20
Roofangle (degrees) 27 ±4 <10
elat(mm) 11.9±1
rf/ra(percent) 70 ±3
Cf-ca(mm) 10.4±2
*see Table I
Fig. 8 Fig. 9
VOL. 73-B, No. 3, MAY 1991
occurred in joints in which the radius of the acetabulum
was larger than that of the femoral head. The difference
between the measurements rf/ra and Cf-Ca in Tables I
and II is significant (p =0.05). The ANOVA test shows
the differences between the measurements rf/ra, Cf-Ca
and RA also to be significant (p =0.05).
Bedouelle (1984) described many shapes of acetabulum
as seen on conventional radiographs, but did not attempt
a classification. We recognise two groups of radiological
features associated with abnormal loading.
Type I: Hips in which the acetabulum is shallow, lies
more vertical than normal, and has a radius of curvature
greater than that of the femoral head. Such joints are
radiologically incongruent (Fig. 3).
Type II: Hips in which the acetabulum provides less than
normal cover for the femoral head (‘short roor), and has
a radius of curvature similar to that of the femoral head.
Suchjoints are congruent (Fig. 2).
A hip of type I is subject to abnormal shear force
and is potentially unstable. Often the labrum is hyper-
trophic and the capsule thickened (T#{246}nnis 1984). CT
scans show the acetabulum elongated in the craniocaudal
direction. The smallest diameter of this oval shape lies
transversely and matches the diameter of the femoral
head. Hypertrophy of the labrum and capsule can be
interpreted as a physiological response to the shear force
and an attempt to correct the bony mismatch of the joint.
Eventually the overstressed labrum may become de-
tached from the acetabular rim ; in these cases the rim
itself is unlikely to be overloaded (Fig. 8).
A hip of type II, which is congruent, is essentially
stable. However, the relative shortness of the acetabular
roof reduces the area of the loaded surface which is then
subject to increased pressure, particularly at that part of
the acetabular margin which lies against the upper pole
of the femoral head (Greenwald and O’Connor 1971;
Pauwels 1976 ; Bombelli 1983). The force evokes local
remodelling (Stadler et al 1982 ; Rubin 1984 ; Klaue and
Perren 1989) the result ofwhich may be a fatigue fracture
and separation of a rim fragment (Fig. 9). Often, there
are associated intra-osseous cysts in the acetabular roof
which communicate with the joint. These are concen-
trated at the overloaded roof edge. By their confluence
they may bring about fragmentation, and the appearance
of a so-called os acetabuli.
Reports of possible acetabular fatigue fractures are
few (Schmidt 1967; Maurer 1970; Kaps and Niethard
1986), and none of these authors commented on the
significance of the limbus. The associated hip dysplasia
is rarely mentioned (Fiedler 1951). Analysis of our own
cases suggests that fatigue fractures, with or without bone
cysts, only occur in congruous (type II) hips. In some of
our cases early radiographs were available in which no
bony fragments were visible. It is possible that some
fragments may represent persistent embryological rem-
nants which, in consequence ofoverload, fail to integrate.
Whatever the type ofdysplasia, a lesion at the acetabular
rim and the consequent shear forces generated are likely
eventually to cause instability and progressive degenera-
tion of the whole joint.
Ganglia or cysts around the hip joint have been
reported by many authors (Harrison, Schajowicz and
Trueta 1953 ; Eggers et al 1963 ; Samuelson, Ward and
Albo 197 1 ; Margreiter, Steiner and Mikuz 1 978 ; Garcia
and Chevalley 1985 ; Bergenudd et al 1987).
Cysts within soft tissues are more likely to occur in
the oval, unstable joints (type I) and partial detachment
ofthelimbus may be the initiating cause. Fetal dissections
have shown that a defect can occur between the labrum
and the rim at a very early stage of development : this
may constitute an area of potential vulnerability in the
adult (Walker 1981). A valvular pumping mechanism
from the joint to the cyst may play a part (Jayson and
Dixon 1970). Such a mechanism would fit in with our
proposition that ganglionic cysts arise through local
overloading secondary to reduced acetabular cover for
the femoral head. Cyst formation within the limbus may
be analogous to cystic degeneration in a knee meniscus
(Ueo and Hamabuchi 1984; Matsui, Ohzono and Saito
1988). No one has previously suggested that acetabular
dysplasia may be an essential precursor of cysts and
ganglia around the hip.
Cysts or ganglia within bone arise through splits in
Figure 8 -Pathophysiology of the acetabular rim in
the incongruent, type I hip. In this configuration, the
labrum is overloaded and may shear from the
acetabular bony rim. Figure 9 -Pathophysiology of
the acetabular rim in the congruent, type II hip. In
this configuration, the resultant force acts upon a
reduced articular surface. A ‘fatigue’ fracture may
occur causing a bony fragment or os acetabuli.
the acetabular cartilage (Landells 1953). These develop
after injury to the subarticular bone and multiple foci of
such damage may allow penetration of synovial fluid
deep to the subchondral bone plate to form cysts in the
cancellous bone (Freund 1940). Synovial fluid may also
penetrate bone through a defect between a damaged
limbus and the articular cartilage (Itoigawa, Azuma and
Kako 1980) which may be why such cysts were found in
hips with acetabular dysplasia of type II. Intra-osseous
ganglia are often visible on CT scans while remaining
undetectable on conventional radiographs despite their
occasionally large size. Our observations confirm the
report of McBeath and Neidhart (1976) that juxtalabral
intra-osseous ganglia may communicate with extra-
osseous ganglia.
In the past we have treated acetabular dysplasia by
the familiar techniques of shelf arthroplasty and Chiani
osteotomy. However, these techniques are extra-articular
and do not address the problem of the limbus tear. These
operations may eliminate pain if it is caused solely by
instability, but where the pain arises from the acetabular
rim syndrome the causative lesion may remain hidden
beneath such extra-articular cover, and may continue to
give rise to symptoms and to predispose to progressive
degeneration (Saito et al 1989). A better principle by
which to improve both femoral head cover and joint
congruency is to re-orientate the acetabulum (LeCoeur
1965 ;T#{246}nnis,Behrens and Tscharani 1981). Techniques
to achieve this are, however, both major and technically
It is not clear what should be the surgical manage-
ment of the damaged limbus or the detached bone
fragment. The merit of refixing the limbus to the bony
rim may be questionable. Conversely, limbus resection
may impairjoint lubrication by removing the hydrostatic
function of the structure (Takechi, Nagashima and Ito
1982), and so hasten degenerative change (Butel et al
The acetabular rim syndrome is best recognised
through awareness of its existence, appreciation of its
symptoms and understanding of its aetiology.
We thank Dr C. Engel of the MEM Institute of Biomechanics, Berne,
for the statistical evaluation of our data and Mrs D. Hansen (Seattle,
Washington, USA) for preparation ofthe manuscript. Mr D. Reynolds,
FRCS, of London, had the patience to revise the whole manuscript and
we owe him our gratitude for his help.
No benefits in any form have been received or will be received
from a commercial party related directly or indirectly to the subject of
this article.
Mblnus B. Icones ossium foetus humani. Leidae Batavonum, 1737:
Altenberg AR. Acetabular labrum tears : a cause of hip pain and
degenerative arthritis. South MedJ 1977; 70:174-5.
Arho AO. Accessory bones ofextremities in roentgen picture. Duodecim
1940; 56:399-410.
Bedouelle J. La dysplasie primitive de Ia hanche chez l’enfant Ct
l’adolescent. In : Cahiers d’enseignement de la SOFCOT, Confer-
ences d’enseignement 1984, lere serie, Paris 1984 :29-54.
Bergenudd H, Bengnir U, Telbag H, Hjelmqvist B. Ganglion of the hip:
an unusual cause of soft tissue swelling of the groin. Arch Orthop
Trauma Surg 1987; 106:274-5.
Bombeffi R. Osteoarthritis ofthe hip : classfication and pathogenesis : the
role ofosteotomy as a consequent therapy. Second ed. Berlin, etc:
Springer-Verlag, 1983.
Butel J, Fran#{231}ois M, Charignon G, Garrel J-F, Faure C. Effets de la
resection du limbus sur Ic d#{233}veloppement ultCnieur du toit
cotyloldien. Acta Orthop Belg 1973 ;39:598-604.
Caudle RJ, Crawford AH. Avulsion fracture of the lateral acetabular
margin. J Bone Joint Surg [Am] 1988 ;70-A : I 568-70.
Currier BL, Fitzerald RH. Acetabular labrum tears of the hip. Trans
AAOS 55th annual meeting, Atlanta, 1988.
de Cuveland E, Heuck F. Osteochondropathie der spina iliaca anterior
inferior unter BerUcksichtigung den ossifikationsvorgange den
apophyse des lateralen pfannenrandes. Arch Orthop Unfall Chir
1957; 48:430-45.
Dameron TB. Bucket-handle tear of acetabular labrum accompanying
posterior dislocation of the hip. J Bone Joint Surg [Am] 1959; 41-
A :131-34.
Dorrell JH, Catterall A. The torn acetabular labrum. J Bone Joint Surg
[Br] 1986; 68-B :400-03.
Eggers GWN, Evans EB, Blumel J, Nowlin DH, Butler JK. Cystic
change in the iliac acetabulum. J Bone Joint Surg [Am] 1963 ; 45-
A :669-686.
Fiedler J. Osteochondrosis dissecans am oberen Pfannenrand des
Hueftgelenkes. Fortschr Geb Rontgenstrahlen 1951 ; 74:207-12.
Freedman E. Os acetabuli. J Bone Joint Surg 1934; 31 :492-95.
Freund E. Pathological significance of intra-articular pressure. Edin-
burgh MJ 1940; 47:192-203.
Fromme A. Die Bedeutung der Looserschen Umbauzonen fuer unsere
klinische Auffassung (Os acetabuli und Gelenkkoerpen). Arch f
k/in Chir 1921 ;I 16:664-80.
Ganz R, Klaue K, Vlnh iS, Mast JW. A new pen acetabular osteotomy
for the treatment of hip dysplasias: technique and preliminary
results. C/in Orthop 1988; 232 :26-36.
Garcia J, Chevalley P. Kystes synoviaux de la hanche. Diagnostic par
tomodensitomCtnie. J Radio/ 1985 ;66:425-32.
Greenwald AS, O’Connor JJ. The transmission of load through the
human hipjoint. J Biomechanics 1971 ; 4:507-28.
Harrison MHM, Sch*jowicz F, Trueta J. Osteoarthnitis of the hip : a
study of the nature and evolution of the disease. J Bone Joint Surg
[Br] 1953; 35-B :598-626.
IkedaT, Awaya G, Suzuki S,Okada Y, Tada H. Torn acetabularlabrum
in young patients : arthnoscopic diagnosis and management. J Bone
JointSurg[Br] 1988; 70-B:l3-6.
Itoigawa Y, Azuma H, Kako K. A histopathological study on aging
processofthe acetabulum with special reference to the pathogenesis
of the acetabular cyst. [Author’s translation] J Jap Orthop Assoc
1980; 54 :223-33.
Jayson MI, Dixon AS. Valvular mechanisms in juxta-articular cysts.
AnnRheumDis 1970; 29:415-20.
Kapandjl [A. Funktionelle anatomic den gelenke : schematisierte und
kommentierte zeichnungen zur menschlichen biomechanik. Stutt-
gart, Ferdinand Enke, 1985:24-5.
Kaps HP, Niethard FU. Ermuedungsfrakturen im Hueftgelenksbereich
bei Joggern. Aktuel Traumatol 1986; 16:203-6.
Kargus H. Ueber die Pfannenveranderungen bei den Perthesschen
Krankheit. Z Orthop Chir 1933; 9:99-115.
Klaue K, Perren SM. Unconventional shapes of the plate cross section
in internal fixation : the trapezoid plate. Long term study of bone
reaction in sheep tibiae. Trans AAOS 56th annual meeting, Las
Vegas, 1989.
Klaue K, Wallin A, Ganz R. CT evaluation of coverage and congruency
ofthe hip prior to osteotomy. Clin Orthop 1988 ;232:IS-25.
Krause W. Ueber den Pfannenknochen. Zentra/b/.fd.m. Wissenschaften
1876; 46 :817.
Landells JW. The bone cysts of osteoarthritis. J Bone Joint Surg [Br]
1953; 35-B :643-49.
LeCoeur P. Correction des d#{233}fautsd’onientation de l’articulation coxo-
fCmorale par osteotomie de l’isthme iliaque. Rev Chir Orthop 196;
51 :21 1-2.
VOL. 73-B, No. 3, MAY 1991
Lequesne M, de Seze S. Le faux profil du bassin : nouvelle incidence
radiographique pour l’Ctude de la hanche. Son utilit#{233}dans les
dysplasies et les differentes coxopathies. Rev Rhum 1961 ;28:
Lilienthal M. Anatomische Untersuchungen ueber das os acetabuli des
Menschen. Dissertation, Koenigsberg, 1909.
Margreiter R, Steiner E, Mikuz G. Das ganglion des hueftgelenkes.
Chirurg 1978; 49 :620-4.
Matsw M, Ohzono K, Saito S. Painful cystic degeneration ofthe limbus
in the hip. A case report. J Bone Joint Surg [Am] 1988:70-A;
448-5 1.
Maurer R. Die Marschrakturen den unteren Extremitaet und des
Beckens. Dissertation, Basel, 1970.
McBeath AA, Neidhart DA. Acetabular cyst with communicating
ganglion : a case report. J Bone Joint Surg [Am] 1976; 58-A :267-69
Niethard FU. Die osteochondrose und osteochondronekrose des
h#{252}ftpfannendaches. Z Orthop 1984; 122:94-8.
Outland TA, Flood JM. Osteochondritis dissecans acetabuli. Am J Surg
1936; 33 :276-81.
Paterson I. The torn acetabular labrum : a block to reduction of a
dislocated hip. J Bone Joint Surg [Br] 1957; 39-B :306-09.
Paterson JMH. An unusual presentation of osteoarthritis of the hip. J
Bone Joint Surg [Br] 1987 ; 69-B :480.
Pauwels F. Biomechanics of the normal and diseased hip : theoretical
foundation, technique and results oftreatment. Berlin, etc : Springer,
Perna G. Sulla ossificazione delI’acetabulum e sul significato del
tuberculum supracotyloideum nell’uomo. Chir Org Mov 1922;
Ponseti IV. Growth and development of the acetabulum in the normal
child : anatomical, histological and roentgenographic studies. J
Bone Joint Surg [Am] 1978 ; 60-A :575-85.
Rashleigh-Belcher HJC, Cannon SR. Recurrent dislocation of the hip
with a “Bankart-type” lesion. J Bone Joint Surg [Br] 1986; 68-
B :398-99.
Rubin CT. Stress fractures : the remodelling response to excessive
repetitive loading. Trans Orthopaedic Research Society 30th
annual meeting, Atlanta 1984.
Rilhle R. R#{246}ntgenologische studien ueber eine mit dem namen os
acetabuli bezeichnete veraenderung am oberen pfannenrand. Arch
fOrthop 1921 ;19:518-41.
Saito S, Nishina T, Ohzono K, Saito M, Takaoka K. Chiari pelvic
osteotomy for osteoarthritis of the hip joint. Trans AAOS, 56th
annual meeting, Las Vegas, 1989.
Samuelson C, Ward JR, Albo D. Rheumatoid synovial cyst of the hip.
ArthritisRheum 1971 ; 14:105-8.
Schmidt H. Rueckbildungeines pfannenrandknochens(”os acetabuli”).
Fortschr Roentgenstr 1967; 106 :471-2.
Schninz HR. Altes und neues zur beckenossifikation. Zugleich em
beitrag zur Kenntnis des os acetabuli. Fortschr Roentgenstr 1922;
Shea KP, Kalamchi A, Thompson GH. Acetabular epiphysis-labrum
entrapment following traumatic anterior dislocation of the hip in
children. J Pediatr Orthop 1986; 6 :21 5-9.
Stadler J, Brennwald J, Fnigg R, Perren SM. Induction of bone surface
resorption by motion : an in vivo study using passive and active
implants. Second symposium on internal fixation of fractures,
Lyon 1982.
Suzuki S, Awaya G, Okada Y, et al. Arthroscopic diagnosis of ruptured
acetabularlabrum. Acta Orthop Scand 1986; S7 :513-5.
Takechi H, Nagashima H, Ito S. Intra-articular pressure of the hip joint
outside and inside the limbus. JJpn Orthop Ass 1982; 56 :529-36.
T#{246}nniSD. Die angeborene hliftdysp/asie und huftluxation im kindes-und
erwachsenena/ter. Springer-Verlag, Berlin, etc. 1984:74-82,125.
Tonnis D, Behrens K, Tscharani F. A modified technique of the triple
pelvic osteotomy : early results. J Pediatr Orthop 1981 ; 1 :241-9.
Ueo T, Hamabuchi M. Hip pain caused by cystic deformation of the
labrum acetabulare. Arthritis Rheum 1984; 27:947-SO.
Walker JM. Histological study of the fetal development of the human
acetabulum and labrum : significance in congenital hip disease.
YaleJBiolMed 1981 ;54 :255-63.
Waschulewski H. Ueber acetabulaere ossifikationszentren und periar-
tikulaere verkalkungen bzw. Verknoecherungen, ihre entstehung
und ihre bedeutung. Arch Orthop Unfallchir 1967; 62 :273-90.
Wiberg G. Studies on dysplastic acetabula and congenital subluxation
ofthe hipjoint. Acta Chir Scand 1939; 83 :Suppl 58.
... Several distinct forms of these ossifications have been described in the literature, including acetabular rim stress fractures, bone apposition of the acetabular rim, labral ossification, and persistence of secondary ossification centers of the acetabulum. [1][2][3][4][5][6][7][8][9] Although their origin is not entirely certain, they have been linked to trauma, hip dysplasia, and, most commonly, femoroacetabular impingement (FAI). 1,[3][4][5][6][9][10][11][12] FAI is a common cause of hip pain and pathology that results from abnormal contact between the proximal femur and the acetabular rim during terminal range-ofmotion. ...
... [1][2][3][4][5][6][7][8][9] Although their origin is not entirely certain, they have been linked to trauma, hip dysplasia, and, most commonly, femoroacetabular impingement (FAI). 1,[3][4][5][6][9][10][11][12] FAI is a common cause of hip pain and pathology that results from abnormal contact between the proximal femur and the acetabular rim during terminal range-ofmotion. 13,14 The 2 most common osseous abnormalities that lead to FAI are a loss of the normal femoral headneck offsetdresulting in cam impingementdand acetabular over coveragedresulting in pincer impingement. ...
... 6,[16][17][18][19][20][21][22] Radiographically, these distinct types of acetabular rim ossicles are oftentimes collectively referred to as "os acetabuli," a term originally used to describe the secondary ossification center of the acetabulum. 4,8,16,18,20,[22][23][24] Because this collective term has been used to describe many types of ossifications, the true prevalence of each distinct form has been difficult to determine. The purposes of this study are to determine the prevalence of 4 different types of acetabular rim ossifications, including partial labral ossification or punctate calcification, true os acetabuli, acetabular rim stress fracture, and complete labral ossification, and to determine whether different types of periacetabular ossifications are linked to demographic or radiological factors. ...
Purpose: To determine the prevalence of 4 different types of acetabular rim ossifications, including partial labral ossification or punctate calcification, true os acetabuli, acetabular rim stress fracture, and complete labral ossification, and to determine whether different types of periacetabular ossifications are linked to demographic or radiological factors. Methods: We retrospectively reviewed the medial records of patients presenting for hip-related complaints at 2 sports medicine practices from September 2007 to December 2009. An anteroposterior radiograph of both hips and a lateral radiograph of each hip was obtained for all patients and reviewed for findings of cam and pincer femoroacetabular impingement, degenerative changes (Tönnis grade), and periacetabular calcifications for both hips. These parameters were also evaluated with respect to symptoms, sex, and age. Results: Four hundred ninety-one consecutive patients (982 hips) presented to 2 orthopaedic surgeons at 2 centers for "hip"-related complaints. There were 223 males and 268 females (age 39 ± 14 years). The overall prevalence of periacetabular calcifications in hips was 17.6%, with 56.6% of calcifications in the symptomatic hip and 43.4% in the contralateral hip. Four basic patterns of calcification were identified: punctuate calcifications within the labrum (8.0% hips), large rounded calcifications (os acetabuli) (4.2% hip), large fragments with a vertical line of the superior-lateral acetabular rim, consistent with healed or non-healed stress fracture (2.0% hips), and complete ossification of the labrum (3.4% hips). Overall, male sex (P = .002), increased lateral center-edge angle (P = .046), and higher Tönnis grade (P < .001) statistically predicted the presence of periacetabular ossification. Punctate calcifications were more prevalent in males (P = .002). Higher Tönnis grade (P = .029) and increased alpha angle (P = .046) were more prevalent with os acetabuli. Younger age (P = .001), male sex (P = .048), increased alpha angle (P = .012), and increased lateral center-edge angle (P < .001) were more prevalent in acetabular rim fractures. No factors were statistically significant at predicting the presence of an ossified labrum. Conclusions: Periacetabular calcifications are not uncommon. Four particular patterns of calcification are identified: punctate labral calcifications (8%), larger rounded calcifications (i.e., os acetabuli) (4.2%), acetabular rim stress fractures (2%), and complete ossification of the labrum (3.4%) for a combined prevalence of 17.6% in patients presenting to an orthopaedic surgeon with "hip"-related complaints. Nearly half were in the asymptomatic hip. Male sex had a higher prevalence of periacetabular calcifications. An increased lateral center edge angle and higher Tönnis grade also had a higher prevalence of periacetabular calcifications. Younger male patients are more likely to have acetabular rim stress fractures. Patients with an increased alpha angle have a higher prevalence of os acetabuli and rim stress fractures. Clinical relevance: This study aims to identify, quantify, and categorize periacetabular calcifications about the hip. Their clinical relationships and relevance have been discussed, but no study has distinctly categorized the various types and their prevalence. This study provides a framework for identification and categorization.
... described[16]. Typically, these patients present with groin pain and a positive anterior impingement test[17]. When FAI is the result of a malunion, such as in femoral neck retrotorsion or varus, these can often be treated with femoral offset correction[6,18]. ...
Unlabelled: Valgus intertrochanteric osteotomy is a well-established treatment in delayed union of femoral neck fractures as it converts shear forces into compression forces. Non-union of the femoral neck fracture may persist following valgus intertrochanteric osteotomy, and secondary femoroacetabular impingement (FAI) may be a contributing factor. Case: We report one case of persistent femoral neck non-union after treatment by valgus intertrochanteric osteotomy with concomitant secondary cam-type impingement from fracture callus as a possible cause for ongoing insufficient healing. Healing was achieved following surgical hip dislocation with corrective osteochondroplasty of the femoral head-neck junction. Two-year follow-up shows good clinical and radiological outcomes. Conclusion: In ongoing non-healing of femoral neck fractures following valgus intertrochanteric osteotomy, secondary cam impingement from fracture callus must be excluded.
... Developmental dysplasia of the hip (DDH) is a challenging problem to manage surgically throughout a patient's life. As adolescents and adults, under coverage of the femoral head by the acetabulum can result in impingement on the labrum and micro-instability, and is a risk factor for developing osteoarthritis [40,41]. Borderline DDH (BDDH) is defined as a lateral center-edge angle (LCEA) of 20-25 degrees [42]. ...
Full-text available
Purpose of Review The use of hip arthroscopy has expanded substantially over the last decade, including in pediatric and adolescent populations. Indications for hip arthroscopy in the pediatric population continue to be refined and research of outcomes following hip arthroscopy has increased. The purpose of this review is to provide an overview of current indications for hip arthroscopy in the pediatric population and the outcomes for each indication. Recent Findings Hip arthroscopy is used in the treatment of a range of pediatric hip conditions, spanning from the infant to young adult. In femoroacetabular impingement, hip arthroscopy in young adolescents has shown improvement in patient-reported outcome measures, high return to sport rates, and low complications. Intra-articular hip pathology secondary to Legg-Calve-Perthes and the persistent deformities following slipped capital femoral epiphysis can be managed with primary hip arthroscopy, and outcomes show significant improvements in patient-reported outcomes. Arthroscopy can be used safely as a reduction aid in developmental hip dysplasia, and as a primary treatment for borderline hip dysplasia in adolescents. In septic hip arthritis, arthroscopic drainage is a safe and effective treatment. Summary Hip arthroscopy is used in the pediatric and adolescent population in the management of femoroacetabular impingement, Legg-Calve-Perthes disease, the sequelae of slipped capital femoral epiphysies, developmental hip dysplasia, and septic arthritis. Research for each of these conditions shows that arthroscopy is a safe and effective treatment when performed for the correct indications, and results are comparable to open surgical options.
The Academy of Orthopaedic Physical Therapy (AOPT), formerly the Orthopaedic Section of the American Physical Therapy Association (APTA), has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). This is an update to the 2014 Clinical Practice Guideline (CPG) for Hip Pain and Movement Dysfunction Associated with Nonarthritic Hip Joint Pain. The goals of the revision were to provide a concise summary of the contemporary evidence since publication of the original guideline and to develop new recommendations or revise previously published recommendations to support evidence-based practice. This current CPG covers pathoanatomical features, clinical course, prognosis, diagnosis, examination, and physical therapy interventions in the management of nonarthritic hip joint pain. J Orthop Sports Phys Ther. 2023:53(7).CPG1-CPG70. doi:10.2519/jospt.2023.0302.
Background: Outcomes after isolated hip arthroscopic surgery for patients with dysplasia have been unfavorable. Results have included iatrogenic instability and conversion to total hip arthroplasty at a young age. However, patients with borderline dysplasia (BD) have shown more favorable results at short- and medium-term follow-up. Purpose: To assess long-term outcomes after hip arthroscopic surgery for femoroacetabular impingement in patients with BD (lateral center-edge angle [LCEA] = 18°-25°) compared with a control group of patients without dysplasia (LCEA = 26°-40°). Study design: Cohort study; Level of evidence, 3. Methods: We identified a group of 33 patients (38 hips) with BD who were treated for FAI between March 2009 and July 2012. An age- and sex-matched control group of 83 patients (96 hips) was also identified. Patient-reported outcome scores were collected preoperatively and subsequently at a mean of 9.6 years postoperatively. Results: The mean LCEA and Tönnis angle were 22.42°± 2.02° and 6.27°± 3.23° in the BD group, respectively, and 31.71°± 3.52° and 2.42°± 3.02° in the control group, respectively (P < .001). At a mean follow-up of 9.6 years (range, 8.2-11.6 years), there was a significant improvement in all patient-reported outcome scores in both groups (P < .001). There were no significant differences between preoperative and postoperative scores or rates of achieving the minimal clinically important difference between the BD and control groups. Bilateral surgery was noted to be a risk factor for any revision during the follow-up period (P < .001). There were 2 hips (5.3%) that underwent revision surgery in the BD group and 10 hips (10.4%) in the control group; of these, 1 patient in the BD group underwent total hip arthroplasty, and 1 patient who had undergone bilateral surgery in the control group underwent bilateral hip resurfacing. Conclusion: Durable outcomes (>9 years) with low revision rates can be expected after hip arthroscopic surgery with an approach that involves labral preservation where possible and careful attention to capsular closure in patients with BD. The observed outcomes were similar to those of a femoroacetabular impingement group with normal coverage. These results highlight the importance of classifying patients into impingement or instability categories and tailoring treatment appropriately with arthroscopic surgery or periacetabular osteotomy, respectively.
Background: To evaluate the relationships among hip instability, pain, and morphology of the iliofemoral ligament (ILFL) in patients with developmental dysplasia of the hip (DDH) using ultrasonography (US). Methods: We reviewed 86 patients (109 hips) with DDH (Group D), 40 patients (46 hips) with borderline hip dysplasia (BDDH) (Group B) and 20 patients (23 hips) without hip pain and bony abnormality (control group). Group D was classified into three subgroups-the severe (group SP), moderate (group MP), and none/mild (group NMP) hip pain groups-using the visual analogue scale (VAS). For evaluating hip instability and ILFL morphology, the distance between the anterior edge of the anterior inferior iliac spine (AIIS) and the horizontal line to the femoral head, and ILFL thickness were measured using US. The difference between the distance in the neutral position and Patrick position was calculated and defined as the femoral head translation distance (FTD). Results: FTD and ILFL thickness in group D were significantly larger than those in the control group and group B (P < 0.05). There was a significant positive correlation between FTD and ILFL thickness in three groups (r = 0.57, P < 0.05; r = 0.55, P < 0.05; r = 0.62, P < 0.05, respectively). FTD and ILFL thickness in group SP were significantly larger than those in group NMP (P < 0.05). FTD and ILFL thickness in group D had significantly negative correlations with the lateral center edge (r = -0.54, P < 0.05; r = -0.40, P < 0.05, respectively) and vertical-center-anterior angle (r = -0.51, P < 0.05; r = -0.43, P < 0.05, respectively). Conclusions: Acetabular bony deficiency, especially in the anterior and lateral region can result in antero-posterior hip instability, leading to thickened ILFL and hip pain, even in patients with BDDH. These findings may facilitate our understanding and treatment of patients with DDH. When hip instability is suspected, hip US examination may help confirm the diagnosis and assist in providing objective clinical diagnostic evidence.
Full-text available
Background: This study aimed to systematically evaluate the value of magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) in the diagnosis of acetabular labral tears. Methods: Databases including PubMed, Embase, Cochrane Library, Web of Science, CBM, CNKI, WanFang Data, and VIP were electronically searched to collect relevant studies on magnetic resonance in the diagnosis of acetabular labral tears from inception to September 1, 2021. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias in the included studies by using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. RevMan 5.3, Meta Disc 1.4, and Stata SE 15.0 were used to investigate the diagnostic value of magnetic resonance in patients with acetabular labral tears. Results: A total of 29 articles were included, involving 1385 participants and 1367 hips. The results of the meta-analysis showed that the pooled sensitivity, pooled specificity, pooled positive likelihood ratio, pooled negative likelihood ratio, pooled diagnostic odds ratio, area under the curve of the summary receiver operating characteristic, and Q* of MRI for diagnosing acetabular labral tears were 0.77 (95% confidence interval [CI], 0.75-0.80), 0.74 (95% CI, 0.68-0.80), 2.19 (95% CI, 1.76-2.73), 0.48 (95% CI, 0.36-0.65), 4.86 (95% CI, 3.44-6.86), 0.75, and 0.69, respectively. The pooled sensitivity, pooled specificity, pooled positive likelihood ratio, pooled negative likelihood ratio, pooled diagnostic odds ratio, area under the curve of the summary receiver operating characteristic, and Q* of MRA for diagnosing acetabular labral tears were 0.87 (95% CI, 0.84-0.89), 0.64 (95% CI, 0.57-0.71), 2.23 (95% CI, 1.57-3.16), 0.21 (95% CI, 0.16-0.27), 10.47 (95% CI, 7.09-15.48), 0.89, and 0.82, respectively. Conclusion: MRI has high diagnostic efficacy for acetabular labral tears, and MRA has even higher diagnostic efficacy. Due to the limited quality and quantity of the included studies, the above results should be further validated.
Full-text available
As knowledge about the origin and morphologic characteristics of hip pain in the young adult has evolved, so too has the clinician’s ability to assess for various pathologies of the hip on radiographs, magnetic resonance imaging (MRI)/magnetic resonance arthrography (MRA), and computed tomography (CT). Because there is no algorithm at this time directly indicating what to do in more subtle hip morphologies, such as microinstability and borderline hip dysplasia (BHD), a skilled hip preservation specialist must use multiple imaging sources and know how to interpret them correctly. Imaging parameters used in the workup for hip dysplasia and BHD include the lateral center-edge angle, Tönnis angle, iliofemoral line, and presence of an upsloping lateral sourcil or everted labrum, among many others. The purpose of this narrative review was to detail various established criteria and parameters on anteroposterior pelvis plain radiographs, MRI/MRA, and CT that assist in defining the nature and severity of instability present in a dysplastic hip, thereby aiding in the development of patient-specific surgical treatment plans.
Full-text available
A patient with recurrent dislocation of the hip is described. The initial injury had been a posterior dislocation without associated fracture of the acetabular wall, and the hip had not been immobilised or protected from weight-bearing during treatment. Exploration of the hip for recurrence revealed disruption of the posterosuperior acetabular labrum with formation of a pouch between the posterior acetabular wall and the short rotator muscles. We have found no previous report of this lesion, which resembles a Bankart lesion of the shoulder. Repair using a bone block is described.
Postmortem studies of ten normal full-term infants and of three children, seven, nine, and fourteen years old, showed that the acetabular cartilage complex is a unit that is triradiate medially and cup-shaped laterally and is interposed between the ilium, ischium, and pubis. This complex is composed of epiphyseal growth-plate cartilage adjacent to these bones, of articular cartilage adjacent to these bones, of articular cartilage around the acetabular cavity, and, for the most part, of hyaline carilage. Interstitial growth within the triradiate part of the cartilage complex causes the hip socket to expand during growth. The concavity of the acetabulum develops in response to the presence of the spherical femoral head. The depth of the acetabulum increased during development as the result of interstitial growth in the acetabular cartilage, of appositional growth at the periphery of this cartilage, and of periosteal new-bone formation at the acetabular margin. At puberty, three secondary centers of ossification appear in the hyaline cartilage surrounding the acetabular cavity. These centers are homologous with other epiphyses in the skeleton. The os acetabuli, which is the epiphysis of the os pubis, forms the anterior wall of the acetabulum. The epiphysis of the ilium, which has been called the acetabular epiphysis, forms a good part of the superior wall of the acetabulum. A small epiphysis of the ischium was seen in the oldest patient, who was fourteen years old. The bone in these epiphyses expands toward the periphery of the acetabulum and thus contributes to its increase in depth.
A common cause of internal derangement of a joint is damage to the fibrocartilaginous structures, such as the meniscus of the knee joint and the discus of the temporomandibular joint. However, there have been no reports of hip pain due to fibrocartilaginous lesions in the hip joint. A deformed cartilaginous labrum due to cyst formation was found in 2 patients who had suffered from hip pain from several years. Their conditions had not been diagnosed correctly because their symptoms had been considered to be caused by sciatica, and radiographic findings of the hip were inconclusive.
The intra-articular pressure of the hip joint of a hemipelvectomized limb was measured outside and inside the limbus. The negative pressure inside the limbus was not sufficient to hold the weight of a leg. The pressure inside the limbus changed chiefly in flexion, extension and internal rotation, however, the pressure outside the limbus changed primarily in abduction, adduction and external rotation. From these pressure changes, it was considered that the limbus was not an airtight valve. Moreover, there seemed to be an air leakage through valve of the limbus.
Seventy-four acetabula from a total of 140 normal human fetuses, obtained from abortions and deaths in the prenatal period, were used. The fetuses ranged from 9.1 to 40 cm in crown-rump length and are believed to be between 12 weeks and term. Acetabula were decalcified embedded in paraffin or celloidin, sectioned, and stained using conventional histologic techniques. Sections from the superior one-quarter of the acetabulum were examined for the initial appearance and later spread of osseous tissue. Throughout the fetal period bone was present only in the floor of the acetabulum and did not extend into the socket walls. Ossification was detected initially more posteriorly in the socket floor, and at all ages, ossification was more prominent on the ischial side of the socket. Despite the lack of osseous tissue a well-formed hyaline cartilage socket was present. The fetal labrum was composed of fibrous tissue with the density of fibers increasing with age. Typical-appearing chondrocytes were detected at only the inner articular margin of the labrum. Contributing from one-fifth to one-half of the socket depth, the labrum may play a greater role in containing the femoral head at birth than it does in the mature joint. In seven acetabula, from joints that were neither subluxated nor dislocated, an area of areolar tissue with capillaries was detected at the hyaline cartilage-labrum junction. Such defects may weaken the labrum and contribute to neonatal hip instability.