Hip resurfacing preserves proximal femoral bone stock, optimises stress transfer to the proximal femur and offers inherent stability and optimal range of movement. The early results of metal–on-polyethylene resurfacing designs were poor and the resurfacing concept was largely abandoned. Modern metal-on-metal articulations enabled the introduction of a new generation of hip resurfacings with encouraging early results. In 1997 two of the authors developed a hip resurfacing system utilizing a metal-on-metal bearing. Our study reports on the clinical and radiological outcomes of the first 200 hips that were treated with the Durom hip resurfacing at an average follow up of 4.6 years (range 3.5–6). Between May 2001 and December 2003, 200 consecutive hip resurfacings were performed on 189 patients, using the Durom hybrid metal-on-metal system. The average age of the patients was 50 years (range 22.5 – 72.3) and 119 were male. Patients were seen at 6 weeks and at 3, 6 and 12 months and annually thereafter for clinical and radiological evaluation. Clinical results were evaluated using the Harris Hip Score. A subjective assessment of patient satisfaction was obtained and patient activity was assessed using the UCLA activity score. No patient was lost to follow up. There were no dislocations and no femoral neck fractures. One femoral component was revised due to aseptic loosening 3.9 years postoperatively. There was one late acute haematogenous infection that was successfully treated elsewhere by debridement and retention of the prosthesis. The mean Harris Hip Score improved significantly from 46.7 preoperatively to 94.4 postoperatively. The mean HHS constituents for pain, function and motion all were significantly improved from the preoperative values of 11.9, 25.7 and 4.2 to 41.8, 43.4 and 4.8 respectively following the resurfacing procedure. The mean UCLA activity score was 7.2 indicating a relatively active patient population and 179 hips were rated as excellent by the patients. No cup was considered radiographically loose. Extensive radiologic changes were observed around the femoral stem in 2.5% of the hips, with migration of the femoral component in one case and stem demarcation in 4 cases. All 5 patients maintained excellent function and had no hip pain. Pelvic osteolysis was observed in 2 cases. Neck remodelling changes were observed in 35 hips (17.5%). Kaplan-Mayer survivorship analysis demonstrated the rate of survival of the resurfacing components to be 99.5% (95% confidence interval 98.5 to 100) with revision for any reason as the endpoint. Early results with the Durom resurfacing system appear encouraging. Although these should be regarded with caution, modern metal-on-metal hip resurfacing potentially offers the ultimate bone preservation and restoration of function in appropriately selected young patients.
To determine if intraoperative positioning in the supine or lateral position affects morbidity and mortality in orthopaedic trauma patients with femur fractures. Retrospective cohort study of 991 patients representing 1030 femoral shaft fractures admitted to our level one trauma center between the years of 1987 to 2006. Primary outcome measures included mortality and admission to ICU. Secondary outcome measures included length of stay in hospital, length of time admitted to the intensive care unit and discharge disposition. Logistic regression analysis was performed to compare to effect of intraoperative position in addition to other known dependent variables on primary and secondary outcome measures. Intraoperative position in the supine or lateral position had no effect on morbidity or mortality in orthopaedic trauma patients with femur fractures. There is no difference in immediate mortality or morbidity between patients with femur fractures treated with IM nails in either the lateral or supine position. We conclude that either position is safe for the surgical stabilization of femur fractures and intraoperative position should be determined by surgeon preference.
Unlike metal-on-Polyethylene, metal-on-metal (MoM) implants seem to affect the adaptive immune response as evident from the associated perivascular infiltrate containing lymphocytes and plasma cells. This is more pronounced in implant failure secondary to aseptic loosening, and may represent the failure mode. A reduction in CD8+ T lymphocyte counts has also been described with Hip Resurfacing. MoM articulations produce a much smaller order of size of wear particles (nanoparticles) than metal-on- Polyethylene, which may be responsible for the observed adaptive immune system effects. We therefore analyzed the effects of CoCr nanoparticles (CoCrNP) on Dendritic Cells, T cells &
B cells. We produced CoCrNP using repetitive short spark discharges between electrodes of prosthetic CoCr alloy. Electron micrography and Brunauer-Emmet-Teller method both confirmed nanoparticle size. The following experiments were then undertaken.
Dendritic Cells were cultured from mouse bone marrow and incubated with CoCrNP of varying concentrations for 24hrs, or lipopolysaccharide as a positive control. Activation status was then characterized by CD40 expression on fluorescence activated cell sorting (FACS) analysis. T Cell Viability; Cells from mouse lymph nodes were incubated with CoCrNP in varying concentrations. At 48hrs, Propidium Iodide (PI) was added and proportion of CD4+ lymphocytes that were PI+ve determined by FACS analysis. T Cell proliferation; Cells from mouse lymph nodes were cultured in medium without phenol red and incubated with μCD3 (anti CD3), μCD3 + CoCrNP, μCD3 + μCD28 or μCD3 + μCD28 + CoCrNP. At 48hrs, Almar Blue was added &
difference in light absorbance at 570nm &
600nm was then used to determine T cell proliferation at 72hrs. Cells from lymph nodes of an MD4 (Hen Egg Lysozyme (HEL) specific B cell receptor transgenic) mouse were incubated with CoCrNP, HEL (positive control) or CoCrNP + HEL. B cell activation at 48hrs was characterised by CD40 and CD86 expression on FACS analysis. We found CoCrNP did not significantly increase CD40 expression on DCs, neither did it alter CD40 or CD86 expression on B cells. Using a sublethal concentration of CoCrNP as determined from the viability tests, CoCrNP inhibited CD3 &
CD3/CD28 dependent T-cell proliferation. This would indicate CoCrNP reduces T cell proliferation and/or survival, which may explain the observed reduction in CD8+ count with hip resurfacing. Understanding the development of the Peri-vascular infiltrate associated with MoM implants will however, probably require more complex (most likely in vivo) models.
We therefore analyzed the effects of CoCr particles on T cells &
B cells. We also analyzed it effects on dendritic cells, which are the key antigen presenting cells to T helper cells.
Dendritic cells (DCs) were harvested from mouse bone marrow &
cultured in medium supplemented with GM-CSF for 6 days, generating DCs typically 80–90% CD11c+. These were incubated with CoCr in concentrations of 25, 10 &
2.5 μg/ml, for 24 hours, or lipopolysaccharide 1 μg/ml as a positive control. Following incubation, activation status of CD11c+ DCs was characterized by MHC Class II, CD40, CD80 &
CD86 expression by FACS analysis. T-Lymphocytes were harvested from mouse lymph nodes &
cultured in medium without phenol red. These were incubated at 5 ×105 cells/well with either CoCr, conA (positive control) or CoCr + conA &
repeated using 2.5 ×105 cells/well. Other positive controls (CD3 &
CD 28) were studied in repeating the experiment. At 48 hours Almar Blue was added &
further incubation for 24 hrs. Light absorbance at 570nm &
600nm was then used to determine T cell proliferation B-Lymphocytes were harvested from the lymph nodes of mice which were only able to mount a B-cell reaction to Hen egg Lysozyme (HEL). These were incubated with medium with CoCr, HEL (positive control) or CoCr+ HEL. The concentration of the CoCr was varied between 25, 10 &
2.5 μg/ml. FACS analysis for markers of B cell regulation was performed after 48 hours incubation..
Intraosseous schwannoma is a rare benign neoplasm, which most commonly arises in the head and neck region particularly the mandible, due to the long intraosseous path of sensory nerves in the mandible. We present a 27-year-old lady with an unusual presentation of an intraosseous schwannoma of the first metatarsal. There is only one report published previously of an intraossous schwannoma of the lesser metatarsal bone of the foot. A 27-year-old woman presented with painful left forefoot following a trip while walking. Plain radiographs demonstrated a pathological fracture through a lytic lesion of the first metatarsal of the left foot. MRI scan using axial T1-weighted spin echo and axial and sagittal T2-weighted gradient echo showed an amorphous mass occupying the medulla of the bone but with a breach of the plantar aspect of cortex with apparent localised destruction. Ultrasound-guided biopsy was performed. Haematoxylin and Eosin stained specimen sections showed a proliferation of spindle cells of alternating hypercellularity and hypocellularity. This case was managed by curettage and grafting with autograft and synthetic bone substitute. At two-year follow-up, the radiographs showed complete graft incorporation and a healed cyst. The patient was clinically asymptomatic with return of full functions. There were no clinico-radiological findings to suggest any recurrence. Due to rarity and non-specific clinico-radiological features, this case illustrates the necessity of a multi-disciplinary approach with an accurate histological diagnosis in combination with radiological and clinical appearances.
The long-term results of patients with multiple knee ligament injuries, i.e. at least 3 ligament ruptures, including both cruciates, in patients entered prospectively onto the trauma database between 1985 and 1999, were reviewed. Forty patients with this injury had modified Lysholm scores at long term follow-up a mean of 8 years post-injury. The mode of operative treatment fell into 3 groups: direct suture or screw fixation of avulsions (Group 1), mid-substance ruptures treated with cruciate reconstruction with hamstring tendons (Group 2), or suture repairs of mid-substance ruptures (Group 3). All operative procedures were undertaken within 2 weeks of injury. Non-operative treatment involved a cast or spanning external fixator (2–4 weeks) followed by bracing. Statistical analysis was performed on the Lysholm scores. The 40 patients in the study group were predominantly young males, 40% had polytrauma, 33% had isolated injuries. Thirteen patients (33%) had non-operative management, the remainder had early operative treatment of their ligament injuries, tailored to the type of ligament injuries identified. Long-term patient outcome data shows statistically significant differences (p<
0.05) between the best results, in patients with direct fixation of bony avulsions (mean = 89), followed by those who had early hamstring reconstruction (mean = 79), followed by those who underwent simple ligament repairs (mean = 65). There was a statistically significant difference (p<
0.05) between the overall scores for the operative group (mean = 80) compared with the non-operative group (mean = 50). Operative treatment of multiple ligament injuries, particularly fixation of avulsions and primary reconstruction of the posterior cruciate ligament appears to yield better results than non-operative or simple repair in the long term follow-up in this group with significant knee injuries.
This study evaluated the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty. One hundred and twenty-six patients who underwent consecutive revision of total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. WOMAC, Oxford-12, SF-12 and patient satisfaction data were obtained at a minimum of two years follow-up. Follow-up was obtained in one hundred and ten patients. There was no significant difference between the two cohorts with regards to outcomes. A patellar prosthesis does not appear to significantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty. The purpose of this study is to evaluate the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty in a matched cohort study. The presence or absence of a patellar prosthesis does not appear to significantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty. Attempting to resurface the patella in revision cases may not be worthwhile. Follow-up was obtained in one hundred and ten patients (fifty-two with patellar component, fifty-eight bony shell), matched for age, sex and co-morbidity scores and followed for a minimum of two years. There was no significant difference between the two cohorts with regards to outcomes of WOMAC pain (mean seventy-two and sixty-five, p=0.17), WOMAC function (mean sixty-four and fifty-nine, p=0.26) scores, Oxford −12 (mean sixty-three and sixty-seven, p=0.2), SF-12 (mean forty and thirty-six, p=0.27) and satisfaction outcomes (mean eight and nine, p=0.07), (power of 0.8, beta=0.2). From January 1997 to December 1999 one hundred and twenty-six patients who underwent consecutive revision total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. At a minimum of two years follow-up, pain and function were assessed by questionnaire for WOMAC, Oxford-12, SF-12 and patient satisfaction data. Co-morbidity, surgical exposure, HSS knee scores and ROM were also collected. Univariate and multivariate analyses were performed. It is questionable whether patient’s pain, function and satisfaction are affected in revision total knee arthroplasty by patellar prosthetic resurfacing.
A concern with diaphyseal-fitting cementless stems in revision total hip arthroplasty is intra-operative fractures. Two hundred and eleven patients consecutively underwent revision hip arthroplasty using Solution stems (DePuy, Warsaw, IN). Intra-operative fractures or perforations occurred in sixty-four patients (30% prevalence), with diaphyseal splits in thirty-nine patients (18% prevalence). Risk factors were pre-operative osteolysis, cortex to canal ratio, under-reaming the cortex and large diameter stems. The majority of diaphyseal linear cracks occurred at the distal end of extended trochanteric osteotomies during stem insertion. Intra-operative fracture is associated with an average two days longer length of stay (p<
0.05). The purpose of this study was to determine the identification of the risk factors and outcomes of intra-operative fractures using a diaphyseal fitting revision stem. There is an association of intra-operative fracture associated using a diaphyseal-fitting stem in revision total hip arthroplasty with a longer length of stay in hospital. Identifying preoperative risk factors will allow avoidance of such fractures and prolonged hospital stay. Intra-operative fractures or perforations occurred in sixty-four patients (30% prevalence) and thirty-nine patients (18% prevalence) sustained diaphyseal splits. Risk factors associated with intra-operative fracture were pre-operative osteolysis, a low cortex to canal ratio, under-reaming the cortex and the use of a large diameter stem. Surgical approach was not directly related to fracture occurrence but the majority of diaphyseal undisplaced linear cracks occurred at the distal end of extended trochanteric osteotomies during stem insertion. Cortical perforation occurred most often with cement removal. Duration of stay was on average two days longer (p<
0.05) for patients with an intraoperative fracture. Two hundred and eleven patients who had undergone revision hip arthroplasty using the Solution stem (DePuy, Warsaw, IN) between December 1998 and March 2002 were identified. Patients who sustained an intra-operative fracture were compared to controls patients who underwent hip revision at the same time frame but with no fracture. Multiple factors were analyzed to see which were risk factors for intra-operative fractures. There is a surprisingly high incidence of intra-operative fracture associated with using a diaphyseal-fitting stem in revision total hip arthroplasty. This was associated with a longer length of stay
Patient satisfaction is not uniform or consistent following revision total knee arthroplasty. This study evaluates ninety-nine patients with a self-administered patient satisfaction questionnaire at a minimum of two years following the revision procedure (1997–99) to determine differences between satisfied (sixty-six patients) and dissatisfied patients (thirty-three patients). Univariate analysis revealed that patients satisfied with their results were significantly different (p<
.05) than dissatisfied patients with regards to post op scores including those of the WOMAC pain and function, oxford, and SF-12. Patients were not different with regards to (p>
.05) age, comorbidity score, surgical approach, or sepsis as a reason for the revision procedure. Regression analysis demonstrated that gender, post-op WOMAC score, and pre-op arc of motion were significant determinants of satisfaction. The purpose of this study is to evaluate determinants of patient satisfaction following revision total knee arthroplasty. Patient satisfaction with revision knee surgery is most strongly associated with both pre and post-operative descriptors of knee function as well as gender. Understanding the variables associated with satisfaction/dissatisfaction following revision knee arthroplasty may further assist ongoing research efforts to improve the outcomes of this procedure. Univariate analysis revealed that patients satisfied with their results were significantly different (p<
.05) than dissatisfied patients with regards to WOMAC pain and function score, oxford knee score, and SF-12. Patients were not different with regards to (p>
.05) age, comorbidity score, surgical approach, or presence of sepsis as a reason for the revision procedure. Regression analysis demonstrated that gender, post-op WOMAC score, and pre-op arc of motion were significant determinants of satisfaction (p<
.05). A self-administered patient satisfaction survey was completed by ninety-nine patients at a minimum of two years following revision total knee arthroplasty. Fifty-nine patients were females and forty were males. Sixty-six patients were satisfied and thirty-three patients were dissatisfied with the outcome of their surgery at two years post-op. Univariate analysis and multivariate regression suggest that pre and post-operative joint function and gender are the most significant determinants of patient satisfaction
The purpose of this study is to evaluate the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty in a matched cohort study. From January 1997 to December 1999 126 patients who underwent revision of total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. At a minimum of two years follow-up, pain and function were assessed by questionnaire for WOMAC, Oxford-12, SF-12 and patient satisfaction data. Co-morbidity, surgical exposure, HSS knee scores and ROM were also collected. Univariate and multivariate analysis were performed. Follow-up was obtained in 110 patients (52 with patellar component, 58 bony shell), matched for age (mean 70 and 67 years), sex and co-morbidity scores and followed for a minimum of two years. There was no significant difference between the two cohorts with regards to outcomes of WOMAC pain scores (mean 66 and 74, p=0.14), WOMAC function scores (mean 59 and 65, p=0.22), Oxford- 12 scores (mean 57 and 64, p=0.17), and satisfaction score outcomes (57 and 68, p=0.14). It remains controversial whether the patient’s pain, function and satisfaction are affected in revision total knee arthroplasty by patellar prosthetic resurfacing. Insufficient patellar bone stock may preclude prosthetic resurfacing in which case patel-loplasty is performed. From this series, the presence or absence of a patellar prosthesis does not appear to sig-nificantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty.
There are a variety of surgical approaches available for open reduction and internal fixation of acetabular fractures. Some centres have avoided the use of the triradiate approach in the belief that it may result in a significantly higher rate of heterotopic ossification. This has not been our experience. In contrast to many centres, acetabular fractures are treated in an emergent manner, with surgery usually undertaken within the first few days post injury. It is the investigators’ belief that this may in part result in a lower rate of heterotopic ossification. The triradiate approach has fallen out of favour in the treatment of acetabular fractures due to concerns with both wound healing and heterotopic ossification. This approach however has been utilised frequently at the Vancouver General Hospital (VGH) in the treatment of acetabular fractures. The purpose of this study was to review the results and complications of this approach experienced in the large series at VGH. We concluded that the results of this approach are acceptable with the exposure allowing anatomical fracture reduction in the vast majority of cases. The complication rate was low, as was the rate of heterotopic ossification. The significance of this study is to highlight that this approach remains extremely useful in the treatment of acetabular fractures, due to its ability to give excellent exposure while still having an acceptably low complication rate. We believe that the ability of our unit to operate on these injuries in an emergent manner may impart the low rate of heterotopic ossification that we have observed. There were a total of one hundred and sixty-one acetabular fractures that were treated operatively with the triradiate approach over the period 1989 to 2001. Of these, the majority were two column injuries (79 or 49%), T type fractures (34 or 21%) and transverse fractures (17 or 11%). The average age of the patients was thirty-seven years and the average time to surgery was three days. Our early complications included five cases of failure of fixation or loss of reduction of the fracture, two cases of neurovascular injury, two cases of superficial wound infection, one case of deep wound infection and one case of wound breakdown. The study involved examining patient hospital records and radiographs and included fracture types, patient ages, delay to surgery, post-operative complications and degree of fracture reduction and healing. Grading of heterotopic ossification was performed by reviewing the anteroposterior radiographs and using Gruen’s classification system.