Developmental dysplasia of the hip
I. Hip arthroscopy as a tool for treating dysplasia remains controversial.
A. Believed not to correct shape of shallow acetabulum.
B. Some studies demonstrated functional improvement and low reoperation rate, especially for mild dysplasia. 1 2 3
C. Recent studies revealed the possibility of a worsened clinical outcome, a high rate of reoperation, subluxation, and progressing osteoarthritis. 4 5 6 7
I. Hip Dysplasia Diagnostic Overview
A. Considerable overlap between impingement related issues and dysplasia-related issues.
(a) Dynamic impingement problems
① Cam lesions
② Rim Lesions
③ Femoral retroversion
④ Perthes induced Cam lesion
⑤ SCFE
(b) Static Overload problems
① Dysplasia - Uncoverage of the socket
② Femoral Anteversion
③ Valgus orientation
I. Assessment
A. Initial challenge is to determine whether the problem is inside the joint, or is the joint a contributing factor?
a Hip joint pathology may co-exist with athletic pubalgia, sports hernia lumbar spinal disorder
b Chronic hip joint symptoms will secondarily lead to compensatory extra-articular findings
l Abductor symptoms
l Pirformis syndrome
l Psoas impingement
l Snapping hip (Coxa saltan)
II. Imaging
A. Radiographs
a Standard views
l AP pelvis, including both hips
¨ Properly centered to assess radiographic indices
¨ Allows comparison of contra-lateral hip for subtle variation
¨ Allows assessment of surrounding areas (ilium, ischium, pubis, sacrum and SI joints
¨ Central Edge angle (Wiberg) 8
Þ CE < 20 degree as dysplasia
Þ CE 25 to 20 as borderline dysplasia
Þ CE > 20 degree as normal
l False profile view of Lequesne 9
¨ More likely to show anterior acetabular deficiency and flat roof angle
¨ Ventral Center-Edge angle (VCA)
¨ Anterior Acetabular Head Index (AAHI)
B. MRI
a Necessitates high resolution study
b At least 1.5 Tesla magnet Surface coils
c Still up to 42% false negative for intraarticular pathology
d Indirect evidence most reliable finding
e Joint Effusion
f Paralabral cyst ; associated with labral pathology
g Subchondral cyst; indicative of articular damage
C. Gadolinium Arthrography with MRI (MRA) 10
a Labral pathology Greater sensitivity labral ; 92%
b Labral pathology 20% false positive
c Cartilage delamination: sensitivity, specificity and accuracy (70%, 57% and 64%)11
D. Delayed Gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) 12
a Poor dGEMRIC index (< 400msec) osteoarthritis
b N=96 dysplastic hips OA defined as 2SD < average, i.e dGEMRIC < 390msec
c Mean dGEMRIC 473 cf normal hips of 570
III. Our case series following Arthroscopic labral repair, cam osteochondroplasty and capsular plication.
A. 38 patients with dysplasia who underwent arthroscopic procedure by single surgeon (SU).
B. 28 hips (6 male, 22 female) met the inclusion criteria. Average age 28.4 years (95% CI 14 to 50)
C. 26 of 28 hips have cam lesion.
D. In 5 of 28 patients, initial arthroscopy failed and required additional surgery (THA 2, RA0, 2 and shelf 1).
E. In 23 of 28 patients , the MHHS and NAHS improved.
F. CE angle < 17 degrees, VCA angle <13 degrees, shenton line broken. Severe cartilage delamination at the time of surgery is a predictor of poor clinical outcome.
IV. Tips on hip arthroscopy for dysplasia
A. In considering arthroscopy for patients with dysplasia, if:
a Dysplasia is the primary mechanical problem, then
l Arthroscopy less relevant
b Dynamic impingement present, then
l Arthroscopy more relevant
B. Indication for arthroscopy in dysplasia:
a Mild lateral or anterior uncoverage
l CE > 20 VCA >20
b No evidence of Osteoarthritis
c No evidence of severe cartilage damage
d No additional femoral deformity such as SCFE and Perthes.
C. Key is to recognize and treat accordingly
a Isolated arthroscopy probably should be approached with great caution.
b Repair, do not debride torn labrum
c No rim trimming
d Protect capsule
e Evaluate dynamic impingement and cam femoral osteoplasty
f No capsulectomy, repair capsular release
V. Surgical technique of endoscopic shelf acetabuloplasty combined with labral repair, cam femoral osteoplasty and capsular plication.
A. Pathophysiology of dysplasia
a Shallow acetabular ▶ Static Overload
b Cam lesion ▶ Dynamic impingement
c Both cause labral tearing ▶ Chondral damage
▶ Instability
d Capsular Laxity ▶ Joint instability
B. Shelf acetabuloplasty Technique
a Central compartment, with traction
l Labral repair
l Microfracture, if necessary.
b Peripheral compartment, without traction
l Evaluate dynamic impingement
l Cam femoral osteoplasty, if needed.
l Capsular closure with ultrabraid.
a Extra-articular endoscopy
l Optimum visualization
l Reflected head of rectus femoris was identified and debrided.
l Two 2.4 mm guide wires were placed along with the capsule
l Osteotome positioned along guide wires, to make the slot.
l Free bone graft measuring 3.0cm X 3.0cm wedge shaped.
l Insert bone shelf into the slot.
References
1. McCarthy JC, Mason JB, Wardell SR. Hip arthroscopy for acetabular dysplasia: a pipe dream? Orthopedics 1998;21:977-979.
2. Byrd JW, Jones KS. Hip arthroscopy in the presence of dysplasia. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association 2003;19:1055-1060.
3. Yamamoto Y, Ide T, Ono T, Hamada Y. Usefulness of arthroscopic surgery in hip trauma cases. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association 2003;19:269-273.
4. Parvizi J, Bican O, Bender B, et al. Arthroscopy for labral tears in patients with developmental dysplasia of the hip: a cautionary note. The Journal of arthroplasty 2009;24:110-113.
5. Mei-Dan O, McConkey MO, Brick M. Catastrophic failure of hip arthroscopy due to iatrogenic instability: can partial division of the ligamentum teres and iliofemoral ligament cause subluxation? Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association 2012;28:440-445.
6. Kalore NV, Maheshwari A, Sharma A, Cheng E, Gioe TJ. Is there a preferred articulating spacer technique for infected knee arthroplasty? A preliminary study. Clinical orthopaedics and related research 2012;470:228-235.
7. Matsuda DK. Endoscopic Pubic Symphysectomy for Reclacitrant Osteitis Pubis Associated With Bilateral Femoroacetabular Impingement. Orthopedics 2010:199-203.
8. Wiberg G. The anatomy and roentgenographic appearance of
a normal hip joint. . Acta Chir Scand 1939; 83(Suppl
58:7-38.
9. Chosa E NT. Anterior acetabular head index of the hip on false-profile views. 2003.
10. Byrd JW, Jones KS. Diagnostic accuracy of clinical assessment, magnetic resonance imaging, magnetic resonance arthrography, and intra-articular injection in hip arthroscopy patients. The American journal of sports medicine 2004;32:1668-1674.
11. Pfirrmann CW, Duc SR, Zanetti M, Dora C, Hodler J. MR arthrography of acetabular cartilage delamination in femoroacetabular cam impingement. Radiology 2008;249:236-241.
12. Jessel RH, Zurakowski D, Zilkens C, Burstein D, Gray ML, Kim YJ. Radiographic and patient factors associated with pre-radiographic osteoarthritis in hip dysplasia. The Journal of bone and joint surgery American volume 2009;91:1120-1129.