Conventional Total Hip Replacement Research Articles

No functional impairment after Robodoc total hip arthroplasty: gait analysis in 25 patients.

The Robodoc total hip replacement procedure requires a wider exposure of the proximal femur, especially of the greater trochanter, than the standard procedure. Moreover, the leg must be placed in a rigid leg-holder apparatus to obtain fixation in maximal hip adduction and external rotation. This may impair the hip abductors and reduce hip abduction in the mid- and terminal stance phase of the cycle. In this study we compared patients after Robodoc and conventional total hip arthroplasty with three-dimensional gait analysis (VICON System, Oxford Metrics, Oxford, U.K.) to assess the kinematics of the pelvis and hip. 25 patients underwent total hip replacement by means of the Robodoc total hip arthroplasty system, 25 patients were treated with conventional total hip replacement, and 40 healthy volunteers served as controls. None of the patients undergoing total hip replacement, robotic or conventional, obtained normal kinematic gait patterns 6 months after surgery. However, the reduction in hip abduction did not differ significantly in patients undergoing robotic or conventional total hip arthroplasty, which suggests that the robotic procedure did not impair hip abductor function more than the conventional method.

Robot-assisted total hip replacement in primary and revision cases

Cementless total hip replacement is the standard indication in robot-assisted orthopedic surgery. The communication between the surgeon and the computer system distinguishes robot-assisted surgery from conventional total hip replacement surgery. This communication begins with the establishment of a preoperative plan by the surgeon on the Orthodoc computer workstation. Although this planning process is guided by a menu, it requires a thorough analysis of the patient's anatomy by the surgeon. The next crucial step during robot-assisted surgery is registration, which is the matching of the virtual world and the real world by the robot. During registration, the surgeon assists the robot by guiding it either to fiducial markers (pins) or surface points at the femoral neck. Once registration is completed, the surgeon has to connect the patient's bone to the robot and provide access for the end-effector to the bone. The latter step sometimes requires scrupulous soft tissue management. Failure to provide access to the bone will lead to force-freezes, interruptions of the reaming, and ultimately, to prolongation of the procedure. The use of the robot in revision cases requires special attention to the quality of the bone to prevent fractures during positioning and fixation. If the surgeon complies with the routines of the computer, the robot will transfer the preoperative plan with highest accuracy.

STANMORE COMPARED WITH CHARNLEY TOTAL HIP REPLACEMENT

From 1982 to 1987, we randomised prospectively 413 patients requiring primary total hip replacements to receive either a Stanmore or Charnley prosthesis. They were reviewed by an independent observer in an attempt to correlate a number of factors including femoral head size with longevity. There were 213 Stanmore hips and 200 Charnley prostheses. At five to ten years (mean 6.5) 76 patients had died and 16 arthroplasties had required revision. Seven were radiologically loose in asymptomatic patients. There was only one case of deep infection. We found no difference statistically in the clinical outcome or in the revision rate of 4% in the two types of prosthesis. The revision rate was greater for trainees than for senior operating surgeons, and there were recognisable technical errors in seven of the nine Stanmore, and four of the seven Charnley replacements which required revision. Retrospective radiological analysis of a random subset of 51 Charnely and 57 Stanmore femoral components showed no difference in femoral subsidence, but in 14 patients who had had bilateral replacements with one femoral component of each type, there was greater early subsidence of the Stanmore prosthesis. Our results confirm that conventional cemented total hip replacements give acceptable results in a general teaching unit, and we found no evidence of any effect of the size of the femoral head on wear or loosening at five to ten years.

Operative correction of an unstable total hip arthroplasty.

We reviewed the results of reoperation in ninety-five patients who had acute subluxation (ten patients) or dislocation (eighty-five patients) of the hip after conventional cemented total hip-replacement arthroplasty. Postoperatively, fifty-eight patients (61 per cent) had no subsequent dislocation or subluxation. Seven of thirty-seven patients who had had recurrent dislocation had occasional subluxation during follow-up. Of the remaining thirty patients in whom instability persisted after the reoperation, twenty-eight had at least one dislocation, and nine had bothersome subluxation. Ten of these thirty-seven patients had another operation for the persistent instability. The causes of instability were classified as malrotation of the component, disruption of the trochanteric-abduction mechanism, impingement, or multiple and unknown, and appropriate treatment was provided. The component was revised in forty-five patients, revision and advancement of the trochanteric component was done in twenty-five patients, and impinging bone or cement was removed from six patients; a combination of these procedures was done in nineteen patients. Over-all, fifty-eight procedures (61 per cent) were successful (no additional subluxations or dislocations). We concluded that the results of operative treatment for an unstable total hip replacement can be optimized when a precise determination of the cause of the instability is made and appropriate measures are applied.

Uncemented bipolar double-cup arthroplasty of the hip in inflammatory arthropathy

From 1979 to 1986, 42 uncemented surface arthroplasties were performed in 27 patients with an inflammatory arthropathy of the hip: median age at operation 40 years (range 19–65 ys), median follow-up period 73 months (range 36–120 mo). After 36 months, in 26 of 42 hips, the mean Harris Hip Score was excellent or good (mean 89, range 80–100). In 14 cases, the mean score was fair (76, range 70–79). Overall, those hips with the longest followup period (60–120m) gradually improved over the years. No correlation was found between the clinical score and radiologic complications such as varus tilting of the femoral component, acetabular protrusion of the cup, or heterotopic ossification. Conversion to a conventional total hip arthroplasty was required in four patients. One patient required a total hip arthroplasty 86 months after the initial operation because of a femoral neck fracture. In two other patients, revision was performed after 60 and 32 months respectively because of a preexistent osteonecrosis and a severe foreign body response to polyethylene debris. Both patients had a varus tilting of the femoral component. In the fourth patient, in whom revision surgery was necessary 28 months after surface replacement there was no explanation for the varus shift of the femoral component. Regarding those problems that can appear after conventional total hip replacement in inflammatory arthropathy, we conclude that the uncemented surface replacement of the hip can be a reasonable alternative

Treatment of osteoarthrosis secondary to congenital dislocation of the hip. Primary cemented surface replacement compared with conventional total hip replacement.

Seventy-four cemented conventional total hip arthroplasties (in fifty-five patients) and thirty-seven cemented surface replacements (in thirty-two patients) were done between 1971 and 1984 for treatment of osteoarthrosis secondary to congenital dislocation of the hip. The patients in the first group were older and had more severe dysplasia. In all patients, we tried to position the acetabular component at the level of the true acetabulum. In both groups, the operation relieved pain and improved the function of the hip in the short term. There were fewer and less severe early postoperative complications in the surface-replacement group, but the rate of long-term failure (revision or resection) was substantially higher. Survivorship analysis demonstrated that neither type of operation yielded durable results in younger patients; all revisions were in patients who were less than sixty years old. However, in older patients who had cemented conventional total hip arthroplasty, survivorship was excellent, regardless of the amount of dysplasia.

Post-loosening mechanical behavior of femoral resurfacing prostheses

The survival rate of femoral surface replacements has been low relative to conventional total hip replacements. The purpose of this investigation was to determine whether the early clinical loosening can be explained by mechanical causes. Using linear and nonlinear finite element methods, the pre- and post failure load-transfer characteristics of the femoral surface replacement were analysed, and stress patterns and relative motions at the implant/bone interface were evaluated for a particular hip-loading cycle. Using histology of revision material as a guideline, implant loosening, bone resorption and fibrous interface formation were introduced in the model and their mechanical consequences analysed. The results suggest that the high failure rates are not correlated directly with the chances for primary mechanical failure of the implant-bone interface, but rather indirectly with the sensitivity of the implant design to implant loosening and the propagation of bone resorption and fibrous tissue formation. This mechanism appears to be governed by the proliferation of relative motions between implant and bone. We conclude that the ‘secondary stability’ of implants in general and their capacity to obtain a stable post-loosening configuration is an important design criterion for long-term survival.

透析患者での人工物置換術の成績不良例

Twelve prosthetic hip and knee replacements (eight bipolar endoprosthetic replacements, three conventional total hip replacements, and one hemiarthroplasty of the knee) were implanted between 1978 and 1988 in eleven patients who underwent hemodialysis for chronic renal insufficiency. Five replacements (three conventional total hip replacements, one bipolar endoprosthetic replacement, and one hemiarthroplasty of the knee) in four patients had a failure due to the loosening of the component. In these four patients, the median age at operation was 51 years and the average length of follow-up was 6 years. One of these patients died of infection in both loosened total hip replacements seven years and four months after the operation.

Survival Analysis of T-28 Hip Arthroplasty with Clinical Implications

Seventeen years after its introduction, the T-28 and its successor (the TR-28) have proved to be a successful arthroplasty system, with very low long-term socket and femoral loosening rates, especially in older patients. The 10-year revision rate for aseptic loosening of the socket is only 2 per cent. This form of conventional cemented total hip replacement has provided pain relief and improved function in many individuals who have exhausted nonoperative treatment alternatives. Although there are still unsolved long-term problems for the young active patients, cemented hip arthroplasty continues to play an important role in joint replacement, and remains the treatment of choice in older and relatively inactive patients.

Hip arthroplasty in patients with systemic lupus erythematosus.

Forty-three prosthetic hip replacements (twenty-nine conventional total hip replacements and fourteen bipolar endoprosthetic replacements) were implanted between January 1971 and June 1982 in thirty-one patients who had systemic lupus erythematosus. All but four patients had stage-III or IV osteonecrosis of the femoral head. The median age at operation was forty-three years, and the median length of follow-up was fifty-seven months. Ratings were good or excellent for all but three total hip arthroplasties at a mean of sixty-six months of follow-up. Complications included delayed wound-healing (in approximately 15 per cent) and superficial wound infection (in approximately 10 per cent). The occurrence of these complications could not be correlated with the use of corticosteroids at the time of the operation. Twenty-five per cent of the patients, who were a mean of forty-three years old at operation, died less than five years postoperatively from complications related to systemic lupus erythematosus. Conclusions regarding the systemic effects of hip arthroplasty in patients with systemic lupus erythematosus could not be drawn on the basis of this study. Total hip arthroplasty uniformly provided a good or excellent result in patients of all ages who had systemic lupus erythematosus at a mean length of follow-up of sixty-six months. An increased incidence of local wound complications, which were unrelated to the use of corticosteroids, should be expected in patients with systemic lupus erythematosus who undergo prosthetic arthroplasty of the hip.

Survivorship Comparison of THARIES and Conventional Hip Arthroplasty in Patients Younger than 40 Years Old

Early and high failure rates for conventional hip replacements in young and active patients are well documented. The hypothesis tested in this study is total hip articular replacement by internal eccentric shells (THARIES) resurfacing hip arthroplasty is a sufficiently durable alternative to conventional total hips in patients younger than 40 years old. Survivorship analysis techniques were applied to 106 THARIES and 98 conventional hip replacements. The primary outcome variable investigated was time to failure, as measured by the need for revision of the prosthesis in the absence of sepsis. Other definitions of prosthesis failure were also investigated. Analysis revealed that even within this young, high-risk population there were subpopulations with different risks for failure. The lowest risk patients comprised all rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) patients, regardless of age. The intermediate risk patients comprised all non-RA, non-JRA patients older than 30 years of age and the highest-risk patients were all non-RA, non-JRA patients younger than 30 years of age. A comparison of THARIES and conventional prostheses within each of these three subpopulations revealed similar patterns of failure over time, with the conventional total hip replacement having significantly better hip function than the THARIES group only in the highest-risk population, when using a failure definition of revision surgery for aseptic loosening. A broader and more important conclusion was that all acrylic-fixed implants, THARIES or THRs are predicted to undergo early mechanical loosenings in younger-than-30, non-RA, non-JRA patients. In patients younger than 30 years age acrylic fixation of THA is inadvisable.

Total articular resurfacing arthroplasty. Analysis of component failure in sixty-seven hips.

Total articular resurfacing arthroplasty with the Tara device was performed on sixty-seven hips in sixty-three patients from 1978 to 1981. I analyzed the results, paying particular attention to prosthetic failure. Loosening of the femoral component occurred in one hip and loosening of the acetabular component, in seven hips. All eight required revision to conventional total hip replacement. Fifteen other patients in the series had radiographic evidence of component failure but have had no significant pain to date. They were regarded as having impending failure. Four of the fifteen showed significant stress-shielding on the femoral side, two with simultaneous acetabular lucency at the bone-cement interface. The other eleven showed progressive acetabular lucency. The total anticipated failure rate was 34.3 per cent (11.9 per cent definite and 22.4 per cent anticipated). The ages of the patients at surgery averaged 49.1 years in the actual failure group and 34.2 years in the impending failure group. Factors that may have been responsible for the unacceptably high incidence of component failure include the young age of the patients in whom this operation was performed and their high activity level. Additional reasons for mechanical failure (both definite and anticipated) on the acetabular side include poor cement distribution with resultant micromotion and increased frictional torque with the larger-diameter component of the prosthesis.

Serum concentrations of chromium, cobalt and nickel after total hip replacement: a six month study

Serum specimens were obtained from 15 patients before undergoing conventional total hip replacement and for periods of up to six months postoperatively. The specimens were analysed for chromium, cobalt and nickel by electrothermal atomic absorption spectroscopy. Serum chromium levels were found to rise to a pronounced postoperative peak and then diminish, although not falling to normal mean levels by six months. Serum cobalt levels either remained the same or decreased while serum nickel levels began to rise two to six weeks after surgery. These results are significant in that serum metal concentration changes have been reported for patients receiving metal-on-metal implants but not for patients with metal-on-polymer total hip implants of more modern designs.

Socket and Cup Surface Replacement

Pain relief is the most striking feature following this procedure. In Group I, in which the metal acetabular socket and the metal femoral cup were used, 60 per cent of the patients gained satisfactory pain relief at five to nine years of follow-up. In Group II, in which the metal-polyethylene socket and the metal cup were used, 84 per cent of the patients gained satisfactory pain relief, with 1 to 5 years of follow-up. There have been 12 revision cases in the 130 hips operated on, with the average time to revision being 3 years and 10 months. Revision procedures consisted of the conventional total hip replacement (seven cases), replacement of the socket and/or the cup (four cases), and arthrodesis (one case). The secondary operations could be performed without difficulties, probably because no bone cement was used in our surface replacement. No cases of pulmonary embolism, thrombophlebitis, deep infection, heterotopic ossification, or femoral neck fracture were encountered after the procedure.

Surface replacement of the hip with the Tharies system. Two to five-year results.

The two to five-year clinical results of 200 Tharies surface replacements were comparable to those of conventional total hip replacement. The incidence of systemic complications, dislocations, and sepsis was low. There were ten cases of aseptic and one case of septic loosening. Nine minor secondary procedures were required in the series. In two patients the femoral component shifted asymptomatically into varus angulation, but no revision was needed. Fifty-five per cent of patients for whom serial radiographs were available had some progression of radiolucency, but there was poor correlation between the width of the zone and loosening until the patient became symptomatic. Improved techniques of preparation of the interface and of delivery, compression, and containment of the cement have improved the postoperative radiographic appearance of the more recently treated patients.