Hydroxyapatite femoral stems for total hip arthroplasty: 10- to 13-year followup.

Three hundred eighty hydroxyapatite-coated titanium alloy stems were implanted in a young and active patient population from 1987 through 1990. Within the population, 274 patients (314 hips) had a minimum 10-year and maximum 13-year followup. The average age of the population was 51 years. Thirty-seven percent of the population was 50 years or younger when operated on (average age, 39 years). Osteoarthritis was seen in 63.7% and avascular necrosis in 16.6% of patients. Fifty-four percent of patients were men. Clinically, these patients had early pain relief and rapid restoration of function. The Harris hip score averaged 92 points, and only 1.6% of patients had mild or moderate activity-related thigh pain. Radiographically, progressive remodeling occurred around the implants, 100% were bone stable, and no patient had endosteal distal osteolysis. Two patients had revision surgery for aseptic loosening: one at 2 years postoperative because of a nonunion of a concomitant subtrochanteric osteotomy and one at 9.5 years postoperative because of polyethylene wear and progressive osteolysis. The mechanical failure rate was 0.5%. The results show excellent lasting fixation of this tapered titanium alloy stem coated proximally with a thin, dense layer of hydroxyapatite. The stem has performed well in a young, active, high-risk population and in the hands of various surgeons.

The Frank Stinchfield Award: Morphologic features of the acetabulum and femur: anteversion angle and implant positioning.

Morphologic features of the hips, in particular those features germane to determination of acetabular and femoral anteversion angles and femoral head offset, were studied in 50 male and 50 female human skeletons with bilateral normal joints. Four distinct configurations were identified relative to the anterior acetabular ridge. The majority (121, 60.5%) were curved; 51 (25.5%) were angular; 19 (9.5%) were irregular; and nine (4.5%) were straight. The acetabular anteversion angle measured 19.9 degrees +/- 6.6 degrees (range, 7 degrees-42 degrees) and was significantly larger in females (21.3 degrees +/- 7.1 degrees) versus males (18.5 degrees +/- 5.8 degrees). The notch acetabular angle, which can be identified easily intraoperatively, was defined as the angle created at the intersection of a line from the sciatic notch along the posterior acetabular ridge and a line from the posterior to the anterior acetabular wall. This angle is almost perpendicular (89.0 degrees +/- 3.5 degrees) and, therefore, may provide an accurate estimate of acetabular anteversion during cup placement. Awareness of the anatomic differences between genders for acetabular anteversion angle, anterolateral bowing of the femur, and neck shaft angle may help reduce the relatively higher incidence of dislocation in females and may lead to different implant designs for male and female patients.

Effect of low-friction ion-treated femoral heads on polyethylene wear rates.

Polyethylene wear is a major contributor to osteolysis and subsequent aseptic loosening of prosthetic components in total hip arthroplasty. Use of ion implantation as a surface modification to the metallic bearing component of orthopaedic implants may be an effective means of reducing wear debris at the bearing interface. In July 1991, low friction ion treated femoral heads were introduced. This study evaluates the effect of the low friction ion treated femoral head on polyethylene wear. Fifty-five total hip arthroplasties (53 patients) with low friction ion treated femoral heads followed up a minimum of 3 years were matched with 55 total hip arthroplasties (47 patients) without low friction ion treated femoral heads for the same postoperative period. Socket wear was evaluated radiographically. Case matching and strict inclusion criteria were used to control for known factors influencing polyethylene wear. These criteria included: (1) cases matched for gender and age within 2 years; (2) diagnosis limited to osteoarthritis or avascular necrosis of the femoral head only; (3) femoral head diameter limited to 26 or 28 mm only; (4) hydroxyapatite coated femoral stem of the same design and a metal backed socket of the one of two designs with the same polyethylene insert; and (5) minimum followup of 3 years. The linear wear rate of polyethylene was 0.161 +/- 0.095 mm per year in the group without the low friction ion treated heads and 0.116 +/- 0.101 mm per year in the low friction ion treated group. The volumetric wear rates were 74.5 +/- 44.3 mm3 per year for the group without the low friction ion treated heads and 57.8 +/- 51.1 mm3 per year for the low friction ion treated group. Assuming the sensitivity of these measurements can detect these small differences in wear accurately, these results suggest low friction ion treated prosthetic heads are useful in reducing polyethylene wear at 3-year minimum followup.

Omnifit cementless total hip arthroplasty. A 10-year average followup.

Seventy-six hips in 67 patients were evaluated an average of 119 months (range, 61-150 months) after total hip arthroplasty with porous coated Omnifit femoral and acetabular components. The patients were young (average age, 45 years), and most were male (67%). Two stems and one cup were revised for aseptic loosening, for aseptic revision rates of 2.6% on the femoral side and 1.3% on the acetabular side. Thigh pain was present in three cases, one of which was activity limiting. Twenty-five (35.7%) hips had evidence of osteolysis confined to proximal Gruen Zone 1 or 7 or to the acetabulum (22 proximal femoral, three both). There were no cases of intramedullary osteolysis in surviving stems. Thirteen (17.1%) hips have undergone reoperation for bone grafting of progressive proximal osteolysis without component revision, at an average 93 months after the total hip arthroplasty. At an average 40 months after reoperation, all stems remain well fixed, and there has been no recurrence of osteolysis of grafted femoral lesions. These results suggest that a circumferentially proximally porous coated femoral component in cementless total hip arthroplasty can provide stable fixation for as long as 12 years after implantation and caseal the canal from distal osteolysis. Serious concerns remain about the incidence of proximal femoral osteolysis.

Fixation of acetabular cups without cement in total hip arthroplasty. A comparison of three different implant surfaces at a minimum duration of follow-up of five years.

We evaluated 377 patients (428 hips) who had been managed, by a total of fourteen surgeons at twelve clinical sites in the United States and Europe, with a porous-coated press-fit acetabular cup, a hydroxyapatite-coated threaded screw-in cup, or one of two similar designs of hydroxyapatite-coated press-fit cups between April 1987 and November 1992. The same type of hydroxyapatite-coated femoral stem was inserted without cement in all patients. After a minimum duration of follow-up of five years (mean, 7.9 years; range, 5.3 to 9.1 years), one (1 per cent) of the 131 hydroxyapatite-coated threaded cups, two (2 per cent) of the 109 porous-coated press-fit cups, and twenty-one (11 per cent) of the 188 hydroxyapatite-coated press-fit cups had been revised because of aseptic loosening. A common radiographic sign of impending failure of the hydroxyapatite-coated press-fit cups was radiolucency at the interface between the implant and the subchondral bone beneath it. This radiolucency usually was seen initially more than two years after implantation. Radiographic evaluation of the 383 acetabular implants that were in situ at the time of the most recent follow-up showed that 123 (99 per cent) of the 124 hydroxyapatite-coated threaded cups, 101 (98 per cent) of the 103 porous-coated cups, and 139 (89 per cent) of the 156 hydroxyapatite-coated press-fit cups were stable with osseous ingrowth (as indicated by the absence of radiolucency at the interface and the absence of migration within the acetabulum). The probability of revision due to aseptic loosening was significantly greater for the hydroxyapatite-coated press-fit cups than it was for the hydroxyapatite-coated threaded cups or the porous-coated press-fit cups (p < 0.001 for both comparisons). Within the group of patients who had a hydroxyapatite-coated press-fit cup, the probability of revision due to aseptic loosening was significantly greater in association with a young age (p = 0.003), female gender (p = 0.02), the use of a femoral head with a diameter of thirty-two millimeters (p = 0.018), and the use of a thin polyethylene liner (p < 0.001). We found that the hydroxyapatite-coated threaded cups and the porous-coated press-fit cups continued to perform well more than five years after the operation. The hydroxyapatite-coated press-fit cups that were revised probably failed because the fixation interface beneath the cup could not sustain the tensile stresses that were imposed between the cup and the bone by the activity of the patient. Our data suggest that, in the specific biomechanical environment of the acetabulum, physical interlocking between the cup and the supporting bone beneath it may be a prerequisite for long-term stability.

Salvage of a recurrently dislocating total hip prosthesis with use of a constrained acetabular component. A retrospective analysis of fifty-six cases.

Fifty-six constrained acetabular components were placed, between April 1988 and February 1993, in fifty-five patients who had had recurrent dislocations (average, six dislocations; range, two to twenty dislocations) of the femoral component after a previous total hip arthroplasty. All patients had additional factors contributing to the instability of the implant, including absence or disruption of the abductor mechanism, poor health, mental retardation, confusion, and Alzheimer disease. One patient was lost to follow-up. The remaining patients were followed clinically for a minimum of three years (average, sixty-four months; range, thirty-seven to ninety-seven months) or until the time of death. During the follow-up interval, only two (4 per cent) of the fifty-five patients had a subsequent dislocation. The use of this type of component should be considered for patients who have recurrent dislocation if other treatment modalities are unlikely to be effective.

Oral administration of doxycycline reduces collagenase and gelatinase activities in extracts of human osteoarthritic cartilage.

OBJECTIVE: To determine whether oral administration of doxycycline in clinically relevant doses will suppress activities of collagenase and gelatinase in extracts of human osteoarthritic (OA) cartilage. METHODS: Femoral heads were obtained from 21 patients undergoing arthroplasty for endstage hip OA. Activities of collagenase and gelatinase were measured in extracts of the OA cartilage from patients who received doxycycline, 100 mg bid or qam for 5 days before surgery (n = 5 and n = 6, respectively), 200 mg as a single dose 3 days before surgery (n = 4); or no doxycycline (n = 6). RESULTS: Five days of doxycycline treatment, in a dose of either 100 mg bid or 100 mg qam, inhibited gelatinase activity in the cartilage extracts (p = 0.003, 0.008, respectively). The bid dose also inhibited collagenase activity (p = 0.002), but inhibition of collagenase with 100 mg qam did not quite reach statistical significance (p = 0.055), in comparison with the values for the untreated OA controls. The single 200 mg dose, given 3 days before procurement of the cartilage, was ineffective in inhibiting metalloproteinase activity. CONCLUSION: Oral administration of doxycycline significantly inhibited collagenase and gelatinase activity in human OA cartilage. The effective dose is likely to be well tolerated during chronic administration, e.g., in a clinical trial to assess the potential of the drug to modify cartilage breakdown in OA.

Nonunion of extended trochanteric osteotomies in impaction grafting femoral revisions.

Extended trochanteric osteotomies have been recommended to facilitate femoral component removal, femoral cement removal, and acetabular exposure in cases of difficult revision hip arthroplasty. Complications due to the osteotomy have been rare and no nonunions have been reported when this osteotomy has been used in conjunction with extensively porous-coated implants. It has been suggested that the osteotomy should also work well with impaction grafting revisions. This is a report of two cases of nonunion of extended trochanteric osteotomies in which the impaction grafting technique was used.

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.

Hydroxyapatite in total hip arthroplasty. Clinical results and critical issues.

Surgeons who perform arthroplasties have posed some critical questions about hydroxyapatite. Does hydroxyapatite coating enhance bone ingrowth or ongrowth? Will hydroxyapatite lead to increased polyethylene wear or an increased incidence of osteolysis? Will the hydroxyapatite coating disappear, and if so, what will be left to maintain implant fixation? A multicenter study of 316 hips (282 patients) with a proximally hydroxyapatite coated stem and either a hydroxyapatite or porous coated cup were followed up 8.1 years (range, 5.6-9.9 years). The average patient age was 50 years (range, 16-81 years), and 61% of the patients were male. One (0.3%) stem, three (2.7%) porous coated cups, and 25 (11.9%) hydroxyapatite coated cups were revised for aseptic loosening. Disappointing results on the acetabular side indicate that substrate design is critical. There were no cases of intramedullary femoral osteolysis, and the incidence of acetabular and proximal femoral osteolysis- and polyethylene wear was no greater than that seen with other cementless or cemented components. Based on these clinical results and a critical review of the literature, it is concluded that hydroxyapatite coated hip components do enhance ingrowth or ongrowth with no increased incidence of osteolysis for as many as 10 years. Concern about the disappearance of the hydroxyapatite coating with time seems moot in light of the above clinical findings.

Hydroxyapatite coated implants. Total hip arthroplasty in the young patient and patients with avascular necrosis.

Two high risk groups for total hip arthroplasty, 136 patients (155 hips) younger than 50 years of age (average age, 38 years) and 44 patients (53 hips) with the diagnosis of avascular necrosis, have a minimum followup of 5 years and a mean followup of 6.8 years. The average Harris Hip Score at last followup totaled 93 and 90, respectively, and thigh pain was reported in 1.3% and 3.8%, respectively. All patients in both groups received the same hydroxyapatite coated femoral stem and the mechanical failure was 0%. No stem was revised for aseptic loosening, 100% of stems were bony stable by radiographic criteria, new bone formation was progressive about the femoral stem, and 0% endosteal lysis was found. The acetabular components had a mechanical failure rate of 10% and 7.5%, respectively, without osteolysis, and an additional 7% and 7.5% failure as a direct result of progressive osteolysis. The results with the porous press fit and hydroxyapatite threaded sockets were far superior to that of the smooth hydroxyapatite press fit sockets and socket failure was associated with thin polyethylene liners and the use of 32-mm head diameters. These findings show a high success rate with a nonporous hydroxyapatite coated titanium femoral stem. However, hydroxyapatite on a smooth acetabular component yielded less predictable results indicating that for long term fixation of the acetabulum an interlock of bone is preferred.

Hydroxyapatite-coated total hip femoral components in patients less than fifty years old. Clinical and radiographic results after five to eight years of follow-up.

One hundred and thirty-three patients (152 hips) who were an average of thirty-nine years old (range, sixteen to forty-nine years old) received a proximally hydroxyapatite-coated femoral prosthesis as part of a total hip arthroplasty and were followed for a minimum of five years (average, 6.4 years; range, five to 8.3 years) or until revision. The average Harris hip score was 47 points (range, 22 to 77 points) preoperatively and 93 points (range, 49 to 100 points) at the time of the latest clinical evaluation. Two patients who had a well fixed femoral implant had activity-limiting pain in the thigh at the time of the most recent examination. Radiographic changes consistent with bone-remodeling (cortical hypertrophy and bone condensation) typically were seen around the mid-part of the shaft of the prosthesis. Forty-eight (32 per cent) of the 148 hips that were included in the radiographic analysis demonstrated a small amount of erosive scalloping in either zone 1 or zone 7 of Gruen et al., and intramedullary osteolysis was suspected in only one hip. All stems were radiographically osseointegrated according to a modification of the criteria described by Engh et al. Four stems were revised, but none of the revisions were performed because of mechanical failure (two stems were revised in conjunction with a revision of the cup because of pain; one, because of an infection; and one, after a traumatic femoral fracture that occurred six years postoperatively). Thus, the rates of aseptic and mechanical failure were both 0 per cent. The combined rate of failure, which included the two stems that were revised because of pain and the two stems that were associated with pain that limited activity, was 2.6 per cent (four of 152 stems). The over-all clinical results associated with hydroxyapatite-coated femoral components were excellent in this group of young patients after intermediate-term follow-up. A review of serial radiographs showed mechanically stable implants with osseous ingrowth, evidence of stress transmission at the middle part of the stem, and minimum endosteal osteolysis.

Should cardiac disease prevent autologous blood donation?

AIDS has created considerable concern among the public regarding being transfused with potentially infectious blood. However, autologous blood donations are still not maximally provided nor utilized. Significant heart disease disqualifies all allogeneic and most autologous blood donors (American Association of Blood Banks (AABB) Standards 1994). Disqualification is based on the widespread belief that donating blood could possibly be detrimental to their health. However, this belief has not been sufficiently documented. Sixty-eight donors (ages 14-84 years), all with histories of significant cardiac diseases, donated 111 units of whole blood (1-3 units). Twenty-eight patients donated 1 unit, 37 donated 2 units, and three patients donated 3 units. Fifty-nine patients had ischemic heart disease, and nine had valvular heart disease (five with mitral stenosis and four with mitral valve prolapse). No patient received erythropoietin, and only one received equal volume replacement with normal saline during donation. All these patients eagerly wished to donate in spite of being informed of the possible complications. No patient wishing to donate has been refused, and none has experienced any adverse consequences from donating. Forty-four patients underwent total hip/knee replacements. Only 56 units (50%) were transfused to 37 patients (54%). Although our experience is limited, it appears that many patients with histories of well established cardiac diseases can easily tolerate donating blood without compromising their health.

Remodeling of bone around hydroxyapatite-coated femoral stems.

Two hundred and twenty-four total hip arthroplasties were performed in 201 patients with use of a femoral component with hydroxyapatite coating of the proximal portion of the stem. The mean duration of follow-up was seventy-one months (range, fifty-eight to eighty-seven months). Of the 224 arthroplasties, 208 (93 per cent; 190 patients) yielded a good or excellent clinical result. Four patients (2 per cent) reported mild-to-moderate activity-related pain in the thigh, and two (1 per cent) had aseptic loosening. The radiographic findings of progressive new-bone formation (cancellous condensation and cortical hypertrophy) throughout the zones adjacent to the middle and distal portions of the stem were evidence of early, extensive proximal fixation of the implant, with distal stress transfer through the implant, which is stiffer than the surrounding bone. Remodeling of the femur began early, was predictable, and progressed throughout the follow-up period. Cortical hypertrophy about the middle and distal portions of the stem occurred predominantly in the mediolateral plane (in 105 hips [47 per cent], compared with thirteen hips [6 per cent] in the anteroposterior plane), and it was more common in patients who had had poorer bone quality preoperatively. Intramedullary osteolysis was present in one femur (0.4 per cent) at five years; the osteolytic area was less than five millimeters in its greatest dimension and had not progressed at the time of the six-year follow-up evaluation. This low rate of osteolysis suggests that a circumferential coating of hydroxyapatite may effectively minimize migration of wear debris along the femoral stem. The progressive remodeling of the femur about the middle and distal portions of the stem, as evidenced by cancellous condensation and cortical hypertrophy, has not, to our knowledge, been described previously to this magnitude in association with proximally coated (porous or hydroxyapatite-coated) femoral implants.

US of the snapping iliopsoas tendon.

PURPOSE: To determine the value of ultrasound (US) in the diagnosis of snapping iliopsoas tendon. MATERIALS AND METHODS: In three patients, dynamic US of the hip was performed as the flexed, abducted, and externally rotated hip was extended. The contralateral hip was also evaluated. Hip arthrography was performed in all three patients, magnetic resonance imaging in two, and iliopsoas bursography in two, which was successful in only one case. One patient underwent surgical release of the iliopsoas tendon. RESULTS: At US, an abnormal jerk of the iliopsoas tendon during hip motion was correlated with the painful audible snap. The motion of the contralateral iliopsoas tendon was smooth. No intraarticular abnormality was found in two patients, and an associated labral tear was suspected at arthrography in the third patient. The patient who underwent surgical release of the iliopsoas tendon had great improvement. CONCLUSION: US is a useful dynamic noninvasive technique for the diagnosis of snapping iliopsoas tendon.

When is total hip arthroplasty a failure? The patients' perspective.

Total hip arthroplasty (THA) patients (186 primary, 92 revision) were surveyed regarding their satisfaction, their expectations regarding longevity, of the hip implant, and their perspective on the potential or actual need for revision surgery. The vast majority of patients were glad they had the original THA, would do it again if faced with a similar choice, and would recommend it to others. One-third of patients believed their current implants would last the rest of their life. The most common responses to either potential or actual failure were happiness it lasted as long as it did, accepting it as "one of those things," and disappointment. No primary THA patients and only 7% of revision of THA patients indicated that they would consider the primary THA a failure when revision surgery was indicated.

Bupivicaine arthrography of the post-arthroplasty hip.

Addition of bupivicaine, a medium-length-acting local anesthetic, to the contrast material in arthrography of total hip prostheses provides reliable information as to whether the source of pain is intracapsular or extracapsular. In 12 surgically proven cases, complete relief of pain after bupivicaine injection correctly identified an intracapsular source of pain in 10, with only 1 false-positive and 1 false-negative. These results compare favorably with the results of the contrast arthrograms in these patients in localizing the pain even if a specific diagnosis could not be reached. Bupivicaine as an adjunct to contrast material during arthrography provides additional information useful in management decisions regarding the necessity of revision arthroplasty.

Primary cemented total hip arthroplasty: five to twelve year clinical and radiographic follow-up.

A retrospective clinical and roentgenographic study was completed on 131 primary cemented total hip arthroplasties with a minimum of five years follow-up (mean, seven years; range, five to twelve years). Second generation cement technique including plugging of the medullary canal, cement gun filling, and pressurization of the canal was used. Acetabular cement was also pressurized. The total mechanical failure rate of the acetabular components was 18.4% compared to that of the femoral components which was 3.1%. There was a significantly higher incidence of acetabular component failure in rheumatoid arthritis patients (38.9%) compared to a preoperative diagnosis of primary osteoarthritis (14.1%) (p = 0.013). Yet there were no rheumatoid arthritis patients in the femoral component revision group. There were no differences in revision rates for metal-backed versus nonmetal-backed cups (p = 0.113). The average thickness of the proximal medial cement mantle was 2.8 millimeters in the loosening group and 5.4 millimeters in the nonloosening group (p = 0.333). All failures occurred in those patients whose proximal medial cement mantle was less than five millimeters. The authors strongly endorse the use of hybrid total hip arthroplasty and emphasize the need for meticulous surgical technique especially in obtaining a cement mantle of sufficient thickness in the proximal medial aspect of the femur.

Hydroxyapatite in total hip arthroplasty: five-year clinical experience.

Excellent clinical and radiographic results are seen with HA-coated femoral components at 5-year follow up. These stems are well fixed proximally, and the transmission of stress is noted to occur at the transition from the coated to uncoated stem. Longer follow up is needed to determine if the currently stable HA-coated implants will become threatened by wear debris and subsequent osteolysis, as has been the case in many long-term studies of other hip implants.