Thirty total hip replacements in twenty-eight patients in which a Zirconia/Polyethylene articulation was utilized were compared to a control group undergoing total hip replacement utilizing Cobalt-Chrome/Polyethylene articulation. These patients were matched for gender, BMI and pre-operative diagnosis. At nine years after implantation there was no difference in the functional outcome between the two groups and no difference in liner wear rate on x-ray (Livermore technique). There was a 27% revision rate in the Zirconia group compared to the 11.5% revision rate in the Cobalt-Chrome group. Bearing surfaces require long- term clinical follow-up to validate in vitro performance. To determine the benefit of Zirconia on polyethylene versus cobalt-chrome on polyethylene in total hip articulation. Zirconia offers no advantage over a cobalt-chrome head in decreasing in vivo polyethylene wear at ten- year follow-up. Newer bearing surfaces require long- term clinical follow-up to validate in vitro laboratory performance. All primary total hip replacements at this institution are entered prospectively in a database and are assessed on an annual basis. All patients in this study were followed for a mean of nine years with a range of six to thirteen years. Thirty cementless total hip arthroplasties were performed in twenty-eight patients utilizing a Zirconia head coupled with a polyethylene acetabular component. Twenty-six hips have been followed for a mean of nine years. These were matched to a control group of twenty-six hips in twenty-six patients utilizing a cobalt-chrome head coupled with an identical polyethylene liner followed for a mean of ten years (range five to fourteen years). There was no functional difference in outcome at nine years between the two groups utilizing the Livermore technique there was no difference in the liner wear rate between the two patient groups. However, seven hips (27%) of the Zirconia group required revision due to loosening and/or extensive osteolysis around the cup and only three hips (11.5%) required revision in the cobalt-chrome group. Our study demonstrates that although changes in component designs and materials may offer theoretical advantages over current components their effect in vivo remains questionable.
We evaluated the clinical, radiographic, and functional outcome of uncemented total hip arthroplasty (THA) following vascularized fibular grafting for avascular necrosis (AVN) of the femoral head. A group of twenty-two patients who had been converted from a vascularized fibular graft to THA was compared to a similar group of twenty-two patients who had received a THA with no prior graft. The graft group was found to have worse outcomes than the control group as measured by SF-36, and WOMAC scores, as well as a hip score. These results show that vascularized fibular grafting complicates future THA. The Purpose of this study was to evaluate the clinical, radiographic, and functional outcome of uncemented total hip arthroplasty (THA) following vascularized fibular grafting for avascular necrosis (AVN) of the femoral head. These results indicate that functional and clinical outcome following post-graft THA is worse than outcome following THA performed as a primary intervention. Judicious use of the vascularized fibular graft procedure is critical in order to minimize the number of graft failures and avoid the negative outcomes associated with THA after failed vascularized fibular grafting. Twenty-six hips in twenty-two patients who had a THA following a failed vascularized fibular graft were compared to a group of twenty-three hips in twenty-two age and sex-matched patients who had received a THA with no prior graft (combined mean age: 39.0 yrs). Primary outcome measures included the SF-36 (patient-based general health assessment – total score and physical sub-component) and WOMAC (patient-based arthritis specific score) scores at matched follow up times (mean: 6.2years, range: two to fourteen years). An objective hip score was also used, as were several radiographic variables. The post-graft group had lower SF-36 final scores (p<
0.006), lower SF-36: physical function scores (p<
0.001), and lower WOMAC scores (p<
0.045) than the control group. Post-graft THA was complicated by longer operative time (p<
0.025) and greater subsidence of the femoral prosthesis (p<
0.004) compared to controls. Additionally, the post-graft group had worse hip score values (p<
0.05) than controls. Vascularized fibular grafting is a commonly used procedure to cure or delay progression of AVN in the hip. Currently this procedure is used for young (<
40 years) patients with hip AVN who are in an early, pre-collapse stage of the disease. Although the efficacy of vascularized fibular grafting has been proven, up to 29% of grafts fail at five years and need to be converted to THA (Urbaniak
Fifty-five patients undergoing isolated acetabular revisions in fifty-seven hips were available for review. In thirty-three of fifty-seven hips there was no significant acetabular deficiency; of the remaining twenty-four hips twenty underwent allograft reconstruction and four autogenous bone grafting. Mean follow-up was four years with a range of three to seven years; there have been no femoral loosening, and three further surgical procedures for hip instability. All acetabular components at last review were soundly fixed with the exception of one patient who underwent excision arthroplasty at twelve months for deep infection. The purpose of this study was to review the functional outcome and the fate of the femoral stem and revised acetabular component following isolated ace-tabular revision. Findings of the current study demonstrate that isolated acetabular revision does not compromise the final functional nor radiographic outcome in acetabular revision in appropriately selected patients; the fate of the femoral component is not adversely influenced by this procedure. There is no need to remove the femoral component at the time of acetabular revision if the femoral component is well fixed and stable by pre- and intra-operative assessment. Prospectively entered data on fifty-seven hips (fifty-five patients) who have undergone isolated acetabular revision without femoral revision was available for review. All patients were assessed pre-operatively and post-operatively on an annual basis by means of physical examination, x-ray, SF-36 and WOMAC questionnaires. In thirty-three of fifty-seven hips there was no significant acetabular deficiency; of the remaining twenty-four hips, one had a segmental defect, thirteen had a cavitary defect and ten had a combined segmental and cavitary defect. Osteolysis existed in the proximal femur of two hips. Bone grafting in twenty-four hips consisted of morselized allograft in nine; combined structural and morselized allograft used in eleven and autogenous bone used in four acetabular defects. Autogenous bone grafting was done in two femoral osteolytic lesions. Mean follow-up was four years with a range of three to seven years. The mean duration of arthroplasty prior to revision was fourteen years (range four to twenty-three years). There were no nerve palsies, vascular injuries or intra-operative fractures in this patient group. All ace-tabular components at latest review were soundly fixed with the exception of one patient who underwent excision arthroplasty at twelve months for deep infection. Twenty-one of the twenty-four hips with bone grafting demonstrated positive radiographic signs of incorporation; the remaining threehips have a stable interface but no evidence of bone ingrowth. Three of the fifty-seven hips presented with hip dislocations after revision arthroplasty; two were managed by closed reduction; the third by open reduction and soft tissue repair.
This study investigated the effect presence, method, and timing of fixation of femoral shaft fractures have on the morbidity and mortality of patients with pulmonary contusion. In the multiply-injured patient with femoral shaft fractures, early (<
24 hours) fracture stabilization with closed, reamed, statically-locked intramedullary nailing has been shown to decrease morbidity and mortality. Controversy exists as to whether such treatment compromises the outcome in patients that have significant co-existing pulmonary injury. This study is the first to specifically investigate the sub-group of patients that have pulmonary contusion. A retrospective review of patients presenting to a Level One trauma center from 1990 to 2002 with pulmonary contusion identified three hundred and twenty-two cases. Patient characteristics of age, sex, GCS, ISS, AIS, presence of femoral shaft fracture, method and timing of treatment of femoral shaft fracture, and presence of other pulmonary injuries were recorded, as were the outcomes of pulmonary complications (acute lung injury (ALI), ARDS, fat embolism syndrome, pulmonary embolism, and pneumonia), days on ventilatory support, days in the intensive care unit and ward, and death. There were no significant differences in the patient characteristics between groups with and without femoral shaft fracture. Except for an increased likelihood of the femoral shaft fracture group having ALI (RR 1.11), there were no significant differences in outcomes between the femur fracture/non-femur fracture groups. As well, there were no significant differences in outcomes between the groups that had fracture fixation before or after twenty-four hours or had the fracture fixed with or without intramedullary nailing. The presence, method, and timing of treatment of femoral shaft fractures do not increase the morbidity or mortality of trauma patients that have pulmonary contusion.
Revision hip arthroplasty does not bring to the patient the same degree of benefit as the primary operation. We compared two hundred and thirteen patients undergoing revision arthroplasty with five hundred and forty-seven patients undergoing primary total hip replacement. The complication rate in the revision arthroplasty group was approximately twice as high in the primary group (p<
.05) primarily as a result of postoperative dislocation. Both groups of patients had a statistically significant improvement between their pre- and postoperative WOMAC and SF-36 physical scores; however, there was also a statistically significant difference in outcome when the two groups were compared, with primary patients having significantly improved WOMAC and SF-36 physical scores. To compare the outcomes between primary and revision total hip arthroplasty patients at one institution with regard to demographics, complication rates and functional outcome. Revision hip arthroplasty does not bring to the patient the same degree of benefit as does the primary operation. The reason for this is multi-factorial and includes a higher complication rate and lower functional outcome. Further study of the problems associated with revision total hip replacement especially focused on complication rates would appear to be warranted. All patients were entered prospectively in a database and were assessed by means of physical examination, radiographs, SF-36 and WOMAC questionnaires. Patients were followed for a minimum of two years with a range of two to five years. Patients were seen on an annual basis. Five hundred and forty-seven patients underwent primary total hip replacement and two hundred and thirteen patients underwent revision total hip replacement. 53.4% of patients undergoing primary and 52% of patients undergoing revision arthroplasty were female. Mean age at primary hip replacement 61.8 years, revision hip replacement 67.1 years. Post-operative complication rate was 7.6% in primary patients and 14.7% in revision patients (p<
.05); there was no statistically significant difference between the two groups with regard to intra-operative fracture, implant loosening or postoperative infection; there was a statistically significant difference in terms of dislocation with 0.8% of primary arthroplasties and 5.6% of revision patients sustaining at least one dislocation following their surgery (p<
.01). Both groups of patients had a statistically significant improvement between their pre- and post-operative WOMAC and SF-36 physical scores (p<
.0001); however, there was also a statistically significant difference in outcome when the two groups were compared with primary patients having significantly improved WOMAC scores (p<
.0001) and significantly improved SF-36 physical scores (p<
.0001).
The purpose of this study was to determine which activities are important to patients and to determine the severity of those problems. The five most important activities were walking outside, driving, walking indoors, stair climbing and daytime pain. Importance of these did not change postoperatively. The five most severe problems causing limitation were a limp, stiffness, loss of energy, daytime pain and locking. All these activities become statistically less severe over twenty-four months. Activities that are important to patients are different than the problems that are ranked by severity. Surgeons can educate patients that the severity of problems do improve over time following TKA. The objectives of this study were:
to determine the five most important activities and five most severe problems for patients prior to total knee arthroplasty (TKA) using the Patient Specific Index (PASI) and to determine the pattern of change in these activities over twenty-four months following TKA. Activities that are most important to patients are different than problems that patients find severe. Important activities remain important over time. Severe problems become less severe over time. Functional activities and PASI scores improve after TKA. Surgeons can educate patients that the problems they find most severe preoperatively do improve over time following TKA. Important activities remain important. Patients scheduled for elective primary (or revision) TKA at two tertiary care teaching hospitals were enrolled in the study, excluding those not fluent in English and those undergoing TKA for a tumour, acute fracture, or an infection of the prosthesis. Patients completed the PASI pre-operatively, six, twelve and twenty-four months post-operatively. One hundred and nineteen subjects were enrolled, nineteen were excluded. The five most important activities (ten- point scale, ten is most important) preoperatively were (mean; 95% CI): walking outside (6.25; 6.23–6.27), driving (6.17; 6.12–6.22), walking indoors (6.14; 6.12–6.16), climbing stairs (6.12; 6.10–6.14), and daytime pain (5.84; 5.81–5.87). These activities were not statistically less important over time. The most severe problems were limping (4.81; 4.77–4.85), stiffness (4.59; 4.56–4.62), lack of energy (4.51; 4.47–4.55), daytime pain (4.46; 4.43–3.39) and locking (4.38; 4.27–4.49). These were significantly less severe at twenty-four months (p <
.001).
This study (n=126, mean age=68.8 years, males=62) evaluated pre-operative WOMAC pain and physical function, age, gender, general health status, revision severity classification, number of revisions, comorbidity and unilateral vs. bilateral surgery as predictors of WOMAC pain and physical function at twenty-four months post revision hip arthroplasty. Pain improved from 9.3 to 3.6 and physical function improved from 35.4 to 17.1. No factors were predictive of patient function. Decreased pain was predicted by less pain pre surgery (p=0.01) and being male (p=0.04). To determine if pre-operative WOMAC pain and physical function, age, gender, general health status (SF-36), revision severity classification, number of revisions, comorbidity and unilateral vs. bilateral surgery are predictive of WOMAC pain and physical function at twenty-four months post revision hip arthroplasty. Physical function at twenty-four months is not independently predicted by the pre-treatment factors evaluated in this study. Male patients with less pain pre surgery and little comorbidity have less pain post surgery. With the exception of pre-treatment pain, the pre-treatment factors tested in this study provide minimal guidance in identifying factors that might be modified to enhance patient outcome. This prospective cohort study included one hundred and twenty-six patients (mean age=68.8 years, males: females=62:64) who had revision for other than infection or peri-prosthetic fracture. On average from pre-surgery to twenty-four months post-surgery, WOMAC pain improved 9.3 to 3.6 and physical function improved from 35.4 to 17.1. In univariate analysis (t-test, p<
0.05), males tended to have better function (19.6 vs. 14.7) and reported less pain (4.4 vs. 2.8). No other factors were significant in univariate analysis. None of the a priori factors noted above were independently predictive of patient function at twenty-four months in the multivariate model (F=2.06, p=0.04, R2=0.16). Decreased pain with activity at twenty-four months independently was predicted by having less pain pre surgery (p=0.01), being male (p=0.04) and having fewer comorbidities (p=0.07) in the multi-variate model (F=2.9. p=0.004, R2=0.21).
Twelve pairs of fresh-frozen, cadaveric femora were harvested. Each right femur was prepared for the cemented insertion of the femoral component of a total hip implant. Left femora served as matched intact controls. Following insertion of the implants, the distal tip of the stem was identified and an oblique osteotomy was made to represent a periprosthetic fracture. Proximally, plates were secured with cables and distally by bicortical screw fixation (c+s). The twelve pairs of femora were randomly divided into three groups: 1. Zimmer Cable-Ready System, 2. AO 4.5 mm broad, LC-DCP, with Wire Mounts and Double Luque Wires, 3. Dall-Miles Cable Grip System. Specimens were mounted and deforming forces were applied to test the biomechanical stiffness of the constructs. Following testing the plate-cable combinations, the proximal cables were removed and replaced with unicortical screws (s+s). Repeat testing was then performed as per the above protocol. The stiffness of the constructs relative to intact bone decreased (p<
0.05) with fixation utilising cables plus screws (c+s) during four-point bending (69–77%) and offset rotational loading (61–64%). When testing unicor-tical plus bicortical screw fixation (s+s) in these modes, a similar effect was seen. There was no difference between plate systems (ANOVA, p>
0.05). Comparisons of stiffness between cable plus screw combination versus unicor-tical plus bicortical screw combination revealed that the latter method of fixation (s+s) was more rigid (p<
0.05). Our study showed that the three plate-cable systems displayed similar biomechanical stiffness. In addition, when the cables were replaced proximally with unicortical screws, more rigid fixation was obtained in all but one plane of testing. We conclude that the method of plate stabilisation by screws or cables is more significant than the type of plate used for periprosthetic fracture stabilisation.
Two hundred and seventeen consecutive patients (238 hips) underwent total hip arthroplasty using the St Michael’s stem and a non-porous screw ring cup. Patients were followed prospectively clinically using the St Michael’s hip score and radiographically. At an average of 11.9 years (10-13.5 years), 55 patients (59 hips) had died, 23 patients (23 hips) were lost to follow-up. The St Michael’s hip score improved from 13.4 pre-operatively to 21.7 (out of a possible 25) at the latest follow-up. Thirty-seven (24%) of the acetabular components have been revised for aseptic loosening and an additional seven components are radiographically loose. No femoral components have been revised. Using Engh’s criteria one femoral component is definitely loose and two femoral components have stable fibrous ingrowth. Significant stress shielding was noticed in 23 hips (17%) without clinical consequences. Minor osteolysis was seen in 13 hips most commonly around the proximal femur and has not caused symptoms. The St Michael’s stem with its large pore size madreporic surface has comparable results to other porous coated stems with smaller pore size. The St Michael’s stem provided reliable ingrowth and fixation with an acceptable degree of stress shielding. The non-porous screw ring cup had a high failure rate.
An episode of hypotension is common during cemented joint replacement, and has been associated with circulatory collapse and sudden death. We studied the mechanism of hypotension in two groups of six dogs after simulated bilateral cemented arthroplasty. In one group, with no lavage, the insertion of cement and prosthesis was followed by severe hypotension, elevated pulmonary artery pressure, decreased systemic vascular resistance and a 21% reduction in cardiac output. In the other group, pulsatile intramedullary lavage was performed before the simulated arthroplasties. Hypotension was less, and although systemic vascular resistance decreased, the cardiac output did not change. The severity of the hypotension, the decrease in cardiac output and an increase in prostaglandin metabolites were related to the magnitude of pulmonary fat embolism. Pulsatile lavage prevents much of this fat embolism, and hence the decrease in cardiac output. The relatively mild hypotension after lavage was secondary to transient vasodilation, which may accentuate the hypotension caused by the decreased cardiac output due to a large embolic fat load. We make recommendations for the prevention and management of hypotension during cemented arthroplasty.
The hospital records of 222 cases of ipsilateral fractures of the femur and tibia were reviewed, and patients were grouped according to the type of fracture and the method of treatment. Thirty-five per cent of patients required late operation for delayed union or non-union, osteomyelitis, refracture and malunion, regardless of the treatment group. A disturbing factor was the 30% incidence of osteomyelitis in patients treated by fixation of both fractures, almost three times the incidence when only one fracture was fixed. A 30% incidence of delayed union or non-union occurred in patients managed conservatively. Of sixty-three patients personally examined, the worst results found were those following conservative management of both fractures. More use of rigid external fixation and of cast bracing is recommended in the management of the fractured tibia, combined with internal fixation of the femoral fracture. Examination of the knee suggested that, with ipsilateral fractures, disruption of ligaments is a common occurrence and should always be suspected.