Unique Populations:
Dysplasia and the Elderly
J.W. Thomas Byrd
2 2 0
15
Two cohorts with common implications are developmental dysplasia and the elderly.
A propensity for hip joint pathology exists in both populations, and both are generally consid- ered to be a harbinger of poor results with arthros- copy. However, arthroscopy has a role in both of these groups and has been instrumental in gaining an appreciation for the pathomechanics associated with various lesions. Operative arthroscopy can meet with significant success when understanding the appropriate indications within these circum- stances.
DEVELOPMENTAL DYSPLASIA
Developmental dysplasia of the hip (DDH) is not a cause of hip pain. It is simply a morphologic condi- tion that makes the hip vulnerable to an intraarticu- lar lesion that may then become symptomatic. The three most likely structures to be involved are the ac- etabular labrum, articular surface, and ligamentum teres.
Accompanying a shallow bony acetabulum, the labrum may be enlarged, assuming a more important role as a weight-bearing surface as well as added re- sponsibility for joint stability. This hypertrophic labrum is thus exposed to greater joint reaction forces and may be at increased risk for developing sympto- matic tearing.1–3Inversion of the acetabular labrum is also known to occur in association with dysplasia, be- ing entrapped within the joint and again being a source of painful tearing.4,5
The reduced area of the acetabular articular sur- face results in increased contact forces,6,7which can result in early development of degenerative wear and may make the articular cartilage more vulnerable to acute fragmentation.8–11
Third, elongation or hypertrophy of the ligamen- tum teres accompanies lateral subluxation of the femoral head within the acetabulum.12,13Entrapment of this ligament can be a source of significant me-
chanical hip pain, whether from its redundant nature or partial degenerate rupture.
Thus, dysplasia is well recognized as an etiologic factor in the development of various painful in- traarticular lesions that may be amenable to arthro- scopic intervention. In fact, in our study, which is the only published report on outcomes of arthros- copy in a dysplastic population, the results were comparable with those previously published in a general population.14However, several caveats need to be fully appreciated.
It is important to assess patients carefully for the presence of dysplastic disease of the hip. Although ar- throscopic debridement may result in significant symptomatic improvement, it may not seriously in- fluence the long-term outlook. Especially for young individuals, arthroscopy should not be used solely for symptomatic improvement when long-term issues need to be addressed. Specifically, patients who are candidates for osteotomy to improve the joint me- chanics and weight distribution must be carefully assessed.
As noted, the enlarged labrum accompanying a shallow acetabulum may carry greater weight-bearing responsibility as well as provide a buttress to supero- lateral subluxation of the femoral head. It is unlikely that simple debridement of the deteriorated portion of the labrum will accentuate this subluxation potential, but great care must be taken in the debridement pro- cedure, especially avoiding an overly zealous resection.
Similarly, indiscriminate debridement of the lig- amentum teres should be avoided. The vessel of the ligamentum teres remains patent and contributes to the blood supply of the femoral head in a signif- icant percentage of adults. Arbitrary debridement could unnecessarily place the femoral head at risk for avascular necrosis. However, it seems unlikely that debridement of the ruptured portion should present a problem, and it has produced gratifying symptomatic results.
In summary, radiographic evidence of dysplasia is not a contraindication to arthroscopy, nor is it neces- sarily an indicator of poor outcome. Results are more
dictated by the nature of the pathology. Nonetheless, it is prudent to view arthroscopy as but one tool in the complement of resources necessary in the assess- ment and management of patients with developmen- tal dysplasia of the hip.
Case 1
A 14-year-old girl was referred with a 4-month history of painful locking and catching of her right hip. Symp- toms first occurred when simply raising her leg to step over a railing. Her symptoms had since been un- remitting. Her history was remarkable for dysplastic disease of both hips since birth. These were initially treated with closed reduction, but she had subse- quently undergone multiple osteotomies of the prox- imal femur and pelvis. Most recently, she was being evaluated for an acetabular procedure to improve the coverage of her femoral head when she developed in- capacitating mechanical right hip symptoms. Radio- graphs revealed changes consistent with her underly- ing disease and previous surgical procedures as well as slight lateral joint space loss on the right compared with the left (Figure 15.1A).
Based on her symptoms and examination findings, arthroscopy was recommended as a method to assess the extent of intraarticular damage that may be con- tributing to her symptoms and to see if this could be addressed. She was found to have an unstable inverted labrum (see Figure 15.1B). This was debrided in a cau- tious fashion (see Figure 15.1C). Care was taken to ex- cise the entrapped portion contributing to her symp- toms while preserving as much of the remaining labrum as possible to avoid potentially destabilizing the joint. Additionally, there was grade IV articular loss of the acetabulum. The unstable fragments were debrided, creating a stable edge of surrounding carti- lage (see Figure 15.1D). Microfracture of the lesion was performed to stimulate a fibrocartilaginous healing re- sponse (see Figure 15.1E). Occluding the inflow con- firmed vascular access through the perforations (see Figure 15.1F). Postoperatively, she was maintained on a strict protected weight-bearing status for 2 months, emphasizing range of motion. She was then able to re- sume normal light daily activities with resolution of her mechanical hip pain.
Case 2
A 16-year-old boy presented with a 9-month history of pain and locking of his left hip. This first occurred while playing football as a freshman in high school.
He had received no previous specific treatment, but was known to have a developmental abnormality of his hip since early childhood. Radiographs revealed ev- idence of a separate bone fragment within the femoral
head (Figure 15.2A), which was further substantiated by a computed tomography (CT) scan (Figure 15.2B).
With his mechanical symptoms and imaging evidence of a loose fragment, arthroscopy was recommended. The fragment was actually found to be fixed within the femoral head, but there was a grade IV unstable articular fragment over this area that was debrided (see Figure 15.2C–E). Postopera- tively, he had resolution of his mechanical pain and catching.
Case 3
A 37-year-old woman presented with a 4-year history of progressively worsening right hip pain. There was no history of injury or precipitating event; she simply began experiencing discomfort that had worsened over recent months. Twisting maneuvers were especially painful. Her examination findings suggested that her hip joint was the source of pain. Radiographs revealed evidence of modest underlying dysplasia but were oth- erwise unremarkable (Figure 15.3A). Magnetic reso- nance imaging (MRI) was also unremarkable. She then underwent 6 months of continued activity restriction as well as various trials of oral antiinflammatory med- ications and physical therapy without improvement.
She obtained pronounced temporary alleviation of her symptoms from a fluoroscopically guided intraarticu- lar injection of anesthetic.
Based on her clinical circumstances, arthroscopy was offered as the next step in her management. She was found to have a hypertrophic ligamentum teres with an accompanying degenerate rupture that was debrided (see Figure 15.3B–D). Postoperatively, she demonstrated pronounced symptomatic improvement and was able to resume fitness exercises.
ELDERLY
Our population is aging, and the most rapid shift in this age distribution is set to occur as the baby boomers reach their senior years. In the United States alone, the Centers for Disease Control and Prevention estimate that approximately 70 million Americans suffer from arthritis or chronic joint ailments, and, ac- cording to the American Academy of Orthopaedic Sur- geons, approximately 300,000 hip arthroplasties are performed annually.15,16Even in absence of arthritis, the hip joint is known to undergo senile changes. An MRI study has demonstrated an increasing incidence of labral pathology with age, even among asympto- matic volunteers.17An electron microscopy study had documented degenerative labral changes associated with the aging process, and this is consistent with two separate cadaveric studies that showed a 96% preva-
FIGURE 15.1. A 14-year-old girl with acute locking and catch- ing of the right hip. (A) Anteroposterior radiograph demonstrates evidence of residual developmental dysplasia of the hip (DDH) of both hips and changes consistent with multiple previous os- teotomies. Slight lateral joint space narrowing of the right hip is seen compared with the left. (B) Arthroscopic view from the an- terolateral portal demonstrates an unstable entrapped anterior labrum (asterisk). (C) Debridement of the unstable portion of the
labrum is begun, revealing extensive exposed subchondral bone (asterisk) with full-thickness articular loss. (D) Debridement of unstable articular fragments is performed with a basket. (E) Now viewing from the anterior portal, a stable articular edge has been achieved (arrows), and microfracture is begun through the sub- chondral surface (asterisk) that still has a thin covering of fibrous tissue. (F) With suction through the shaver, bleeding confirms vascular access through the areas of perforation.
F E
D C
A B
B A
D C
E
FIGURE 15.2. A 16-year-old boy with pain and locking of the left hip from playing football. (A) Anteroposterior radiograph demonstrates congenital deformity of the joint with a 10-degree CE angle.
(B) Computed tomography (CT) scan demonstrates evidence of a bone fragment within the femoral head (arrow). (C) Arthroscopic view from the posterolateral portal demonstrates an unstable full- thickness articular flap (asterisk). (D) Now viewing from the anterolateral portal, the fragment (asterisk) is excised. (E) A stable edge is created around the crater (asterisk), with no loose bone fragment.
lence of labral lesions in specimens averaging 78 years of age.18–20
As our population ages, there remains an em- phasis on maintaining an active lifestyle. Many in- dividuals wish to maintain the physical prowess of their youth and, for the more reasonably oriented, there are fitness programs designed specifically for aging bodies. There is also greater interest in con- tinuing to participate in competitive activities with advancing age at both the professional and recre- ational levels, which is reflected in the flourishing number of masters programs and senior events.
Thus, the aging hip joint is subjected to many of the same forces (i.e., torsion, twisting, impact load-
ing) that are often a source of injury in younger joints. The mechanism of injury may be similar, but the propensity for injury may be greater because of underlying joint changes, and the recovery may be slower and less complete.
Arthroscopy has a role for many of the conditions that are encountered in older individuals, but ex- pectations of success must be modified because of underlying senile changes or arthritis. Age is not a contraindication to arthroscopy, but is a factor in suspecting the presence of preexisting, subclinical degenerative disease. Several case examples illus- trate the role and limitations of arthroscopy in an aging population.
A
B C
FIGURE 15.3. A 37-year-old woman with recalcitrant right hip pain. (A) Anteroposterior radiograph demonstrates moderate dysplasia with an 18-degree CE angle. (B) Arthroscopy reveals a hypertrophic ligamentum teres (arrows).
(C) The degenerated hypertrophic portion of the ligament is debrided.
FIGURE 15.4. A 74-year-old woman with recalcitrant left hip pain.
(A) Anteroposterior radiograph is remarkable only for subtle joint space loss of the left compared with the right hip. (B) Arthroscopy
demonstrates severe grade IV articular fragmentation of both the acetabulum and femoral head, which is debrided.
A B
C B
A
FIGURE 15.5. A 73-year-old man with acute-onset intractable hip pain. (A) An- teroposterior radiograph reveals modest degenerate changes, but good joint space preservation. (B) Viewing from the anterolateral portal, a large comminuted tear of the anterior labrum (asterisk) is excised. (C) Accompanying areas of grade IV articular fragmentation are debrided as well.
Case 4
A 74-year-old woman presented with a 16-month his- tory of progressively incapacitating left hip pain. Ra- diographs were interpreted to show only mild degen- erative changes (Figure 15.4A), insufficient to explain the magnitude of her symptoms. She had been man- aged under the auspices of four different physicians, having undergone an extensive evaluation of her lower back and a psychiatric consultation with recommen- dation for a pain management program. On examina- tion, her hip seemed to be the principal origin of pain.
This was further supported by a brief period of relief from an intraarticular injection.
Because of the intractable nature of her symptoms, arthroscopy was offered and revealed grade IV articu- lar loss of both the acetabular and femoral surfaces (see Figure 15.4B). Debridement resulted in improve- ment for only a few months. However, with the doc- umented severity of her disease, she was thought to
be an appropriate candidate for total hip arthroplasty.
This procedure was performed with gratifying results.
It has become evident that often subtle radio- graphic findings may have significant clinical impli- cations. It has been our experience that advanced in- traarticular damage may occur before there are any radiographic indicators of change. As in this case, for degenerative disease, when the symptoms are out of proportion to the radiographic findings, often arthros- copy will define more advanced damage in accordance with the patient’s symptoms. Thus, we are beginning to learn how to interpret subtle radiographic features, especially the presence of any asymmetric joint space loss.
Case 5
A 73-year-old man presented with a 1-month history of incapacitating right hip pain that occurred while
FIGURE 15.6. A 69-year-old woman with spontaneous onset of sharp stabbing right hip pain. (A) Anteroposterior radiograph re- veals a well-healed femoral neck fracture with joint space nar- rowing and areas suggestive of a loose body (arrows). (B) CT scan further delineates the presence of an intraarticular fragment (ar- row). (C) Arthroscopy reveals the loose bone fragment, which is retrieved, but there is also evidence of chronic grade IV articular loss, especially of the femoral head, with exposed eburnated bone (asterisk).
C A B
playing golf. Any movement of the hip was painful, and his symptoms were only partially alleviated by using crutches. Radiographs revealed mild degenera- tive changes but fairly good joint space preservation (Figure 15.5A). A bone scan and serologic testing were performed to rule out occult fracture, neoplasia, or in- fection. All results were unremarkable. Evaluation of the lumbar spine was also carried out to rule out a source of referred symptoms. An MRI of the hip was also unremarkable. Because of his recalcitrant symp- toms, a fluoroscopically guided intraarticular injection of bupivacaine and corticosteroid was performed, which provided pronounced alleviation of his symp- toms, but only for a few days. Arthroscopy was sub- sequently recommended. He was found to have ex- tensive tearing of the anterolateral labrum as well as associated grade IV articular fragmentation of the acetabulum, which was excised (see Figure 15.5B,C). Postoperatively, he experienced pro- nounced symptomatic improvement and was able to return to his normal sports activities for the fol- lowing 6 years.
Case 6
A 69-year-old woman was referred with a 6-week his- tory of spontaneous onset incapacitating sharp, stab- bing right hip pain. Her history was remarkable in that she had undergone multiple screw fixation of a femoral neck fracture 9 years previously. However, she had been asymptomatic and unrestricted in her activities until her recent onset of symptoms. Radio- graphs revealed her fracture to be fully healed. Evi- dence suggested an intraarticular loose body, but also modest joint space narrowing (Figure 15.6A). A CT scan further defined the extent of the intraarticular fragment (Figure 15.6B).
It was uncertain how much of her symptoms was simply due to the degenerative changes and how much might be attributable to the bone fragment.
However, with her recent spontaneous onset of sharp stabbing pain and evidence of an intraarticu- lar fragment, it was thought that arthroscopy to re- trieve the fragment was the next step in her man- agement to remove this as a potential contributing source. At arthroscopy, the large loose body was identified and retrieved. However, there was also noted to be severe articular damage with grade IV changes of the acetabulum and grade III damage to the femoral head (see Figure 15.6C). Postopera- tively, the sharp stabbing symptoms were elimi- nated, but she continued to experience pain with daily activities. This was thought to be attributable to her underlying degenerative disease.
In this case, the patient experienced an acute episode of pain, mechanical symptoms, and clear
evidence of an intraarticular loose body, all of which are normally good prognostic indicators of a potentially successful outcome of hip arthroscopy.
However, radiographically, she had evidence of joint space loss reflecting underlying degenerative disease. In our experience, whenever there is ra- diographic evidence of degenerative disease, this is often the limiting factor in the response to ar- throscopy and should be considered an overriding poor prognostic indicator, even in the presence of more favorable clinical findings. Degenerative dis- ease is also often a great imitator. It may present with gradually worsening activity-related symp- toms, but also may present with the acute onset of pain in absence of any prodromal findings.
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