Total hip arthroplasty with cement in patients who have rheumatoid arthritis. A minimum ten-year follow-up study

One hundred and six consecutive total hip arthroplasties with cement were performed by one surgeon, at least ten years before the time of the present clinical and radiographic review, in seventy-five patients who had adult-onset rheumatoid arthritis. Two patients (three hips) were lost to follow-up. Seven (7 per cent) of the remaining 103 hips were revised. The revisions were performed because of infection (three hips), dislocation (two hips), or aseptic loosening (two hips). Of the ninety-eight hips that were not lost to follow-up or revised because of infection or dislocation, eight (8 per cent) had radiographic loosening of the acetabular component and two (2 per cent) had radiographic loosening of the femoral component. Although the prevalence of radiographic loosening of the acetabular component was four times greater than the prevalence of radiographic loosening of the femoral component, the prevalence of revision because of aseptic loosening of the acetabular component was identical to that for the femoral component (one component each). These results compared favorably with those of total hip arthroplasty with cement, performed by the same surgeon, for the treatment of other diagnoses. Loosening of the acetabular component was significantly associated with a younger age at the time of the index operation (p = 0.03) and with acetabular osteolysis (p = 0.0006). Of forty-eight hips in thirty-two patients who survived for at least ten years, 96 per cent (forty-six hips) were considered by the patients to have a satisfactory result. At the time of the latest follow-up, twenty-four (75 per cent) of the patients had no pain in the hip. Although eighteen patients (56 per cent) could walk without support at a minimum of ten years after the operation, we found that the functional results for patients who had rheumatoid arthritis were inferior to those observed for patients who had had a total hip arthroplasty with cement, performed by the same surgeon, for the treatment of other diagnoses.     

Dislocation and instability complicating low friction arthroplasty of the hip joint

Among the complications in a series of 1,400 consecutive Charnley low friction arthroplasty procedures, there were 8 dislocations, and 3 highly unstable hips. Three dislocations followed severe trauma, in 2 of the 3 there was only fibrous union of the greater trochanter. In all but 2 of the hips, more than one previous operation had been performed. More than one technical fault was evident in most dislocations. Six of the 8 dislocations required reoperation. Meticulous attention to the Charnley procedure, including soft tissue elements of the hip joint is necessary to avoid instability and dislocation following total hip arthroplasty.     

The fate of pelvic osteolysis after reoperation. No recurrence with lesional treatment

Twenty-three hips (21 patients) with 30 pelvic osteolytic lesions underwent reoperation and were observed prospectively for 25 to 74 months (average, 40 months) to assess the fate of pelvic osteolysis after reoperation. The average radiographic dimensions of the lytic lesions were 2.4 x 1.9 cm with the largest lesion measuring 7 x 5 cm. The porous ingrowth acetabular component shell had been left in situ in 15 hips and had been revised in eight. There was no difference in the average lesional size for hips with revised shells compared with those with unrevised shells. In cases where the shell was left in situ, the osteolytic lesions were curetted by working around the component perimeter or through holes in the shell. In 18 hips the bone defect(s) were grafted with autograft or allograft. Regardless of the management of the acetabular shell or the absence or presence of bone graft, none of the osteolytic lesions have progressed. Twenty-six of the 30 lesions have increased radiographic density. All acetabular components remain radiographically well fixed. There were no new osteolytic lesions. All hips were functioning well, and none have required subsequent reoperation for any reason. There was a statistically significant reduction in the operative time and the amount of blood loss when the acetabular component was not revised. It does not appear necessary to remove a well fixed and well positioned cementless acetabular component for the treatment of pelvic osteolysis. Debridement of periarticular inflammatory tissue and lesional curettage, either with or without bone graft, is effective in managing this type of bone loss. Revision of the acetabular component shell was associated with a significant increase in operative time and blood loss. These results support routine radiographic evaluation after total hip arthroplasty to monitor the development of osteolysis. On the basis of this experience, the authors recommend lesional treatment of progressive pelvic osteolysis to avoid more difficult surgery and minimize patient morbidity.     

Radiotherapy for elderly patients

Fifty-seven revision total hip arthroplasties in fifty-six patients were performed with a Harris-Galante porous-coated acetabular component by one surgeon, and the patients were followed prospectively for a mean of seven years (range, five to twelve years). A trochanteric osteotomy was performed in forty hips, and a posterior approach with an extended anterior capsulectomy was used in the other seventeen. The acetabular defect was classified as segmental in seven hips, cavitary in twenty-three, and combined in twenty-one; six hips had no notable defect. A bulk allograft was used in eleven hips, and morseled cancellous-bone allograft or autogenous graft was used in thirty-four hips; twelve hips did not have bone-grafting. Both the femoral and the acetabular component were revised in forty-five hips, and only the acetabular component was revised in twelve. Thirty-nine hips (68 per cent) had a good or excellent clinical result according to the Harris hip score. The acetabular component was well fixed in the fourteen hips that had a fair result and the four hips that had a poor result. The acetabular component was considered to have migrated if there was a change in the angle of the cup of 5 degrees or more or a change in the horizontal or vertical position of the cup of more than three millimeters. Despite varying degrees of bone loss, no acetabular component had radiographic evidence of loosening at the latest follow-up examination. No component was revised and no revisions were scheduled. One hip was debrided for a late metastatic infection, but the component was well fixed and was not revised. There were no complications related to the use of screws for fixation. These mid-term results confirm the early success of acetabular revisions performed with fixation of a titanium fiber-metal-coated hemispherical component with multiple screws and no cement.     

Automated seeded lesion segmentation on digital mammograms

The clinical results of eighty-four total hip arthroplasties performed through a transtrochanteric approach in sixty-seven patients who had a high dislocation of the hip (the femoral head completely out of the acetabulum), from 1976 to 1994, were reviewed. The acetabular component was placed in the true acetabulum and the femur was shortened at the level of the femoral neck, along with release of the psoas tendon and the small external rotators, in order to facilitate reduction of the components and to avoid neurovascular complications. Eleven hip prostheses (13 per cent) failed at a mean of 6.4 years (range, two months to sixteen years) postoperatively; the failure was due to aseptic loosening of both components in four hips, aseptic loosening of the stem only in three, late infection in three, and malpositioning of the acetabular component that caused recurrent dislocations in one. The other seventy-three hips were functioning well at the latest follow-up examination, two to twenty years (mean, 7.1 years) postoperatively. The overall cumulative rate of success was 92.4 per cent (95 per cent confidence interval, 89.5 to 95.3 per cent) at five years and 88.0 per cent (95 per cent confidence interval, 82.2 to 93.8 per cent) at ten years. We believe that this operative technique of total hip arthroplasty is effective for the treatment of the difficult condition of high dislocation of the hip.     

Relationship of femoral head and acetabular size to the prevalence of dislocation

Two clinical studies, one prospective randomized and one retrospective, were performed to evaluate the relationship of femoral head size and acetabular component outer diameter to the prevalence of dislocation of the modular total hip replacement. Between October 1995 and April 1996, 31 primary total hip arthroplasties in 30 patients were randomized to a femoral head diameter of 22 mm or 28 mm, for two groups of acetabular components of outer diameters of 56 mm or larger and 54 mm or smaller. Head size (22 mm) and acetabular component outer diameter (> or = 56 mm) were found to increase the risk of dislocation. From December 1984 to January 1994, 308 primary total hip arthroplasties were performed through a posterior approach by one surgeon using a modular 28 mm femoral head and one type of uncemented acetabular component. The rate of dislocation for acetabular components with an outer diameter of 62 mm or larger was increased significantly (five of 36 hips, 14%) compared with those with an outer diameter of 60 mm or smaller (11 of 272 hips, 4%).     

Primary hybrid total hip arthroplasty: an interim followup

The senior authors' initial experience with primary hybrid hip replacement in patients with osteoarthritis was studied to evaluate the efficacy of the procedure. Hybrid total hip arthroplasty (uncemented Harris-Galante acetabular component and cemented Iowa precoated femoral component) was performed in 131 consecutive, nonselected hips in 118 patients with the diagnosis of primary osteoarthritis. Followup was performed at 8 to 9 years after the procedure. The average age at the time of the procedure was 68 years (range, 45-87 years). There were 50 men (55 hips) and 68 women (76 hips). At final followup 19 patients (22 hips) had died. The femoral component had been revised for aseptic loosening in 8 hips (6.1%). One additional hip showed definite radiographic loosening. Hence, the prevalence of radiographic femoral failure was 6.9% (9 hips). No acetabular component had been revised for aseptic loosening and no acetabular component had migrated. The senior author continues to perform hybrid total hip arthroplasty in all patients with primary osteoarthritis. However, design modifications have been made in the femoral component that is used.     

Isolated revision acetabuloplasty using a porous-coated cementless acetabular component without removal of a well-fixed femoral component. A 3- to 9-year follow-up study

The results of isolated acetabular revision performed in 31 patients (32 hips) were monitored for between 3 and 9 years. All femoral components were well fixed and not removed or revised at the time of index surgery. There were 4 hips with little or no acetabular bony defect, 2 hips with pure segmental defects (type I), 10 hips with cavitary defects (type II), 15 with combined segmental cavitary defects (type III), and I with pelvic discontinuity (type IV). All revision acetabular implants were cementless, using a porous-coated hemispheric cup with or without bone-graft. There were four grade I reconstructions, 16 grade II reconstructions, and 12 grade III reconstructions. At final follow-up evaluation 94% of the cups were judged to be stable. Two hips required a second revision acetabuloplasty because of loss of fixation of the cup. The 2 repeat revisions were also done without removal of the femoral component. One acetabular component had evidence of rotational migration, which stabilized and remained nonprogressive. There were no cases of femoral component radiographic or clinical failure. The mean pre and postoperative hip scores were 44 and 83, respectively. The pre- and postoperative pain scores were 12 and 42, respectively. The findings of this study suggest that isolated acetabular revision, using a cementless porous-coated hemispheric cup, can be successfully performed without removing or revising a well-fixed femoral stem and not compromise the final outcome.     

Charnley total hip arthroplasty in patients less than fifty years old. A twenty to twenty-five-year follow-up note

We evaluated the results twenty to twenty-five years after ninety-three consecutive, nonselected Charnley total hip arthroplasties performed with cement by the senior one of us in sixty-nine patients who were less than fifty years old at the time of the procedure. Seventy of the seventy-two hips in the living patients were followed radiographically for at least twenty years. Twenty-seven hips (29 per cent) had a revision or a resection of the prosthesis during the follow-up period. The revision or the resection was performed because of aseptic loosening in twenty-one hips (23 per cent), infection in four (4 per cent), dislocation in one (1 per cent), and fracture of the femur in one. Eighteen acetabular components (19 per cent) and five femoral components (5 per cent) were revised because of aseptic loosening, and an additional fourteen acetabular components (15 per cent) and seven femoral components (8 per cent) demonstrated definite or probable radiographic loosening. The present study demonstrates the long-term durability of total hip arthroplasty performed with cement in an active population of patients. The fixation of the femoral component was found to perform better than that of the acetabular component at twenty to twenty-five years after the procedure.     

Total hip arthroplasty with porous-coated prostheses fixed without cement in patients who are sixty-five years of age or older

We reviewed the results of 212 total hip arthroplasties performed without cement in 203 unselected, consecutive patients who were sixty-five years of age or older. The outcome was known for 196 hips, thirty-seven of which had been followed until the death of the patient and 159 of which had been followed for a minimum of five years. A reoperation was done in 4 percent (seven) of the 196 hips. These reoperations included one revision because of loosening of the stem and five revisions of the cup. Three of the acetabular revisions were done because of fracture due to polyethylene wear; one, because of recurrent dislocation; and one, because of polyethylene wear and a fracture due to lysis. In the seventh reoperation, a cup and stem were exchanged because of infection. The probability that a hip prosthesis would survive twelve years without a reoperation was 0.92 (95 percent confidence interval, 0.85 to 0.99). We evaluated the clinical results for 152 patients who had not had a reoperation and had been followed for at least five years (mean, 8.5 years; range, five to fourteen years). Of these patients, thirteen (9 percent) had pain that limited activity: five (3 percent) had pain in the thigh (four patients) or groin (one patient), and eight (5 percent) had trochanteric pain and tenderness. One hundred and forty-four (95 percent) of the patients noted an improvement in overall function, and 149 (98 percent) reported satisfaction with the outcome. One hundred and thirty-five hips that were not revised were followed radiographically for at least five years (mean, 8.2 years; range, five to fourteen years). In this group, osteolysis was observed in three hips (2 percent); loosening of the cup, in three (2 percent); and loosening of the stem, in one (1 percent). Stress-shielding was seen on the two-year postoperative radiographs of forty-five (26 percent) of the 174 hips that were followed for at least that duration. The prevalence of osteolysis, loosening of a component, and reoperations was no greater in this subgroup than in the overall group. These results indicate that total hip arthroplasty without cement can be successful in older patients. This study also provides a reference for comparison with the results of total hip arthroplasty performed with cement and those of so-called hybrid total hip arthroplasty (an acetabular component fixed without cement and a femoral component fixed with cement) in patients who are sixty-five years of age or older.     

Salvage of total hip instability with a constrained acetabular component

Between April 1988 and February 1993, 101 constraining acetabular components were implanted into 98 patients. One patient was lost to followup at 8 months. Otherwise, all patients were observed until death or for at least 2 years minimum followup. The average clinical followup for the living patients was 61 months (range, 24-97 months). Indications for the use of the constrained acetabular components were recurrent dislocation (an average of six dislocations, range 2-20) in 56 cases, intraoperative instability in 38 cases, and neurologic impairment in seven cases. For the entire group there were four cases of recurrent dislocation or failure of the component (4%). For the cases where this component was used for recurrent dislocation, 96% (54 of 56 cases) had no additional dislocations. Radiographically, at this short term followup, there was no evidence of an increased incidence of femoral or acetabular component loosening. The authors recommend judicious use of this component as a salvage measure for desperate cases of hip instability during or after total hip arthroplasty.     

Immunologic aspects of Helicobacter pylori infection and malignant transformation of B cells

We studied the use of overhead traction in the treatment of congenital dislocation of the hip in thirty-five children (fifty hips) whose mean age at the time of the diagnosis was thirty-three months (range, eighteen to seventy-two months). None of the children had had any previous treatment. The mean time in traction was twenty-three days (range, eight to thirty-six days). Closed reduction was successful for relocation of the femoral head in thirty-eight of the fifty hips; twenty of these hips needed no additional treatment, sixteen were treated with an innominate osteotomy because of severe acetabular dysplasia, and two needed femoral derotation and an innominate osteotomy to correct persistent subluxation. In the remaining twelve hips, closed reduction failed at the outset and an open reduction was necessary. Femoral shortening also was performed in seven of the twelve hips to maintain concentric reduction. After a mean duration of follow-up of forty-eight months (range, thirty-two to sixty-five months), thirty-three hips were rated as class 1; seven, as class 2; four, as class 3; and five, as class 4, according to the criteria of Severin. The remaining hip could not be so classified. Avascular necrosis developed in two hips that had been treated with closed reduction followed by Salter osteotomy and in three hips that had been treated with primary open reduction. We found that preliminary overhead traction facilitated closed reduction of untreated congenitally dislocated hips in children who were eighteen to seventy-two months old.     

Treatment of developmental dysplasia of the hip after failed open reduction

It is difficult to obtain a good result by secondary open reduction if a primary open reduction for developmental dysplasia of the hip (DDH) fails. Complications such as avascular necrosis of the femoral head and subluxation of the hip are common. In this study, we retrospectively reviewed the causes of failure of primary open reduction and the final clinical and radiographic outcomes of 32 patients (34 hips) with DDH who underwent repeat open reduction and other procedures from January 1982 to December 1995. The ages of the patients at the time of the secondary operation ranged from 1.5 to 16.5 years (mean, 5.9 yr). The interval from the primary open reduction to the secondary procedure ranged from 3 days to 10 years (mean, 8.9 mo). In most cases (30 hips), the position of the redislocated femoral head was T?nnis grade 3 or 4. Avascular necrosis of the femoral head was evident in about half of the hips before the secondary open reduction. The most common cause of failure of the primary operation was a tight inferior capsule and transverse acetabular ligament, which blocked complete reduction. At a mean follow-up period of 42 months (range, 24-147 mo) after the secondary operation, the radiographic classification was Severin class 1 or 2 in 15 of the 34 hips, and Severin class 3 or worse in the remaining 19 hips. Clinically, according to the modified McKay criteria, 18 of the 32 patients (18 hips) had excellent or good results, and three patients (four hips) had poor results. In conclusion, the main cause of failure of the primary open reduction of DDH was technical error. We believe that detailed preoperative evaluation is critical for the success of primary open reduction of DDH.     

Combined procedure of open reduction and shortening of the femur in treatment of congenital dislocation of the hips in older children

A one-stage, combined operative procedure for reduction of congenitally dislocated hips in older children consists of shortening of the femur; open reduction by an inferior approach to the joint; reconstruction of the acetabular roof; correction of anteversion of both the femoral neck and the neck-shaft angle; anterior transposition of the iliopsoas muscle. On 60 hips operated in children, ages 5 to 15 with a follow-up period, ranging from 5 to 9 years, the results were found to be excellent in 3 per cent, good in 60 per cent, fair in 30 per cent, and poor in 7 per cent. The procedure is indicated in children up to the time of early puberty. The primary indication is high bilateral dislocation. In unilateral dislocations some residual leg-length discrepancy frequently occurs. This procedure should be done only by orthopedic surgeons who have special training and experience in the treatment of congenital dislocation of the hip.     

Intradural drop metastases in oligodendrogliomas

OBJECTIVE: To observe the developmental changes of the acetabulum after reduction of developmental dislocation of the hip and require evolutionary regularity of acetabular dysplasia. METHODS: A follow-up in an average of 7.4 years was carried out in 117 patients (161 hips) with developmental dislocation of the hip after reduction. By the series of X-ray films, acetabular index, acetabular-head index, Sharp's angle, ACM angle (Idelberger's angle) and anteversion were observed. At the same time, centre-head distance discrepancy was measured. RESULTS: Acetabular index returned to normal gradually as the time went by and significantly within one year after the reduction of developmental dislocation of the hip. The process of recovery was nearly stable three years later. Acetabular index in the dysplasia group was above 39 degrees before reduction and decreased slowly after the reduction. However, it was still up to 30 degrees after 3 years observation. The value of centre-head distance discrepancy decreased gradually as the years went by after reduction. CONCLUSIONS: If acetabular index before reduction is above 39 degrees and is still up to 30 degrees three years after reduction, acetabular dysplasia can be diagnosed.     

Neuroimaging in the high-risk infant: relationship to outcome

PURPOSE OF THE STUDY: Dislocation following total hip arthroplasty (THA) continues to be a problem. An innovative treatment is described with the intermediate Bousquet's prosthesis. This study reported 13 cases and demonstrates its high reliability despite the origins of the dislocation. Recurrent dislocation following initial dislocation, occurs in between 25 to 60 per cent of the cases reported in the literature. The main cause is a malpositioned prosthetic component and especially a retroverted acetabulum. The other reasons for dislocation were: trochanteric non-union, bone or cement impingement, previous surgery, age and neurologic disorder. In every case the instability of the hip may be caused or increased by muscular insufficiency. Various methods are described to control recurrent dislocation: repositioning the component, posterior acetabular wall component, trochanteric advancement, retentive acetabular component, bracing. When the cause is clear and isolated, the rate of success may be 70-80 per cent. This study examines the results of a revision procedure with the intermediate Bousquet's prosthesis. MATERIAL AND METHODS: 13 recurrent dislocations were treated with the intermediate Bousquet's prosthesis. There were 10 women and 3 men with an average age at operation of 73 years. The main cause in 7 cases was an abductor insufficiency including 4 trochanteric non unions. The other causes were 6 component malpositions, 7 previous surgery, 1 impingement. The average delay between the first dislocation and revision was one year. The Bousquet's acetabular component is an steel cup covered with alumina, impacted without cement. The polyethylene component is free in the cup and retentive on the femoral head. The femoral positioning was not modified. RESULTS: The revision did not correct all of the causes of luxation, however we noted only one case of dislocation and no recurrent dislocations. DISCUSSION: At last follow-up, all recurrent dislocations were controlled. Nevertheless, there remained 7 abductor insufficiencies and 4 femoral malpositionings. In the literature the rate of success depends on the cause. The main difficulty is the treatment of joint laxity. Some authors propose trochanteric advancement, a larger head, a posterior wall acetabular component, retentive acetabular component. Success is not uniform. The Bousquet's acetabular component supports joint laxity and femoral malpositioning. This allows to keep the same original femoral component when the risk is too high for a cemented prosthesis or impossible for a non cemented prosthesis. CONCLUSION: This treatment of the recurrent dislocation is reliable with a short and simple operation.     

Impaired bile flow and disordered hepatic calcium homeostasis are early features of halothane-induced liver injury in guinea pigs

Although an acetabular component with an elevated rim is thought to improve the postoperative stability of a total hip prosthesis, the actual clinical value has not yet been demonstrated. To address this question, we reviewed the results of 5167 total hip arthroplasties that had been performed at our institution from April 1, 1985, through December 31, 1991. The prostheses included 2469 acetabular components with an elevated-rim liner (10 degrees of elevation) and 2698 with a standard liner. The cumulative probability of dislocation was estimated as a function of time since the operation with use of the Kaplan-Meier survivorship method. Forty-eight of the 2469 hips that had the elevated-rim acetabular liner dislocated within two years, compared with 101 of the 2698 hips that had the standard acetabular liner. The two-year probability of dislocation was 2.19 per cent for the hips with the elevated-rim liner and 3.85 per cent for those with the standard liner (p = 0.001). A similar trend was seen at five years; however, because of a smaller sample the difference was not significant. Increased stability at two years was also demonstrated for the hips with the elevated-rim liner when the hips were analyzed according to the operative approach, the mode of fixation, the sex of the patient, and the type of total hip arthroplasty (primary or revision). Although these data demonstrate improved stability after total hip arthroplasty when an elevated liner is used, particularly in hips that are at greater risk for dislocation of the prosthesis, the long-term effect of this elevated liner on wear and loosening remains unknown but is of considerable concern. The elevated liner deserves additional study to clarify its effect on wear and loosening.     

Dislocation after bipolar hemiarthroplasty of the hip

Although bipolar hemiarthroplasty of the hip is a frequently performed procedure, little information is available about the frequency of postoperative dislocation and its treatment. For this study, 1,934 hips treated consecutively with primary bipolar hemiarthroplasty were reviewed. A postoperative dislocation developed in 29 patients (1.5%): during the first month after surgery in 24 patients and between 1 month and 5 years after surgery in five patients. Of the 29 dislocations, 25 were successfully reduced with with routine closed methods. Among these 25 hips, 13 (52%) subsequently redislocated, and 7 of these required operative treatment for the recurrent dislocation. Dislocation after primary bipolar hemiarthroplasty is infrequent, can usually be reduced by routine closed methods, but is associated with a high rate of recurrent dislocation.     

Failure of the Mecring screw-ring acetabular component in total hip arthroplasty. A three to seven-year follow-up study

We prospectively studied the results of 411 consecutive total hip arthroplasties with a Mecring screw-ring acetabular component inserted without cement combined with a Stanmore femoral stem inserted with cement. The duration of follow-up ranged from three to seven years (mean, four years and six months). Three hundred and thirty-one patients (378 hips) were available for physical examination and had a complete set of radiographs. The clinical result was good or excellent for 82 per cent (309) of the 378 hips. However, the rate of radiographic loosening of the acetabular component, as evidenced by migration at the most recent follow-up examination, was alarmingly high: 25 per cent (ninety-five) of the 378 hips. In general, these patients did not have serious clinical symptoms. The cups in women migrated significantly more often (p = 0.003) than those in men. Migration was also more frequent in patients who were less than fifty-one years old and in patients in whom the index procedure was a revision arthroplasty, but these differences were not significant. Twenty-one (6 per cent) of the acetabular cups were revised for aseptic loosening. The high rate of radiographic loosening has led us to abandon the use of the Mecring screw-ring acetabular component.     

Biodistribution and pharmacokinetics of 131I-labeled LEX 032, a recombinant hybrid of antichymotrypsin

Computed tomographic (CT) scans were performed after closed reduction of 68 dislocated hips in 53 infants in spica casts with developmental hip dislocation (DDH). Ten measurements were made on the CT scans including acetabular indices and anteversion, hip-abduction angle, lateral and posterior displacement of the femur from the acetabulum, and femoral displacement from a modified Shenton's line drawn from the pubic rami. By using analysis of variance, the correlation of each variable with outcome after reduction was determined, including the development of avascular necrosis or the need for further surgery because of residual dysplasia. None of the variables was predictive of the outcome of persistent hip dysplasia. The subsequent development of avascular necrosis was statistically associated with hip-abduction angles >55 degrees as measured on postreduction CT scans, with 20% of the involved hips developing avascular necrosis on subsequent follow-up.