Macrodactyly of the foot is a rare but disabling
condition. We present the results of surgery on 18 feet of 16 patients, who
underwent ray amputation and were followed-up for more than two
years at a mean of 80 months (25 to 198). We radiologically measured the intermetatarsal width and forefoot
area pre-operatively and at six weeks and two years after surgery.
We also evaluated the clinical results using the Oxford Ankle Foot
Questionnaire for children (OxAFQ-C) and the Questionnaire for Foot
Macrodactyly. The intermetatarsal width and forefoot area ratios were significantly
decreased after surgery. The mean OxAFQ-C score was 42 (16 to 57)
pre-operatively, improving to 47 (5 to 60) at two years post-operatively
(p = 0.021). The mean questionnaire for Foot Macrodactyly score
two years after surgery was 8 (6 to 10). Ray amputation gave a measurable reduction in foot size with
excellent functional results. For patients with metatarsal involvement,
a motionless toe, or involvement of multiple digits, ray amputation
is a clinically effective option which is acceptable to patients. Cite this article:
A number of studies have reported satisfactory
results from the isolated revision of an acetabular component. However,
many of these studies reported only the short- to intermediate-term
results of heterogeneous bearing surfaces in a mixed age group. We present our experience of using a ceramic-on-ceramic (CoC)
bearing for isolated revision of an uncemented acetabular component
in 166 patients (187 hips) who were under the age of 50 years at
the time of revision. There were 78 men and 88 women with a mean
age of 47.4 years (28 to 49). The most common reason for revision
was polyethylene wear and acetabular osteolysis in 123 hips (66%),
followed by aseptic loosening in 49 hips (26%). We report the clinical and radiological outcome, complication
rate, and survivorship of this group. The mean duration of follow-up
was 15.6 years (11 to 19). The mean pre-operative Harris hip score was 33 points (1 to 58),
and improved to a mean of 88 points (51 to 100) at follow-up. The
mean pre-operative total Western Ontario and McMaster Universities
Osteoarthritis Index score was 63.2 (43 to 91) and improved to 19.8
points (9 to 61) post-operatively. Overall, 153 of 166 patients
(92%) were satisfied with their outcome. Kaplan–Meier survivorship
analysis, with revision or radiological evidence of implant failure
(13 patients, 8%) as end-points, was 92% at 15 years (95% confidence
interval 0.89 to 0.97). Isolated revision of a cementless acetabular component using
a CoC bearing gives good results in patients under 50 years of age. Cite this article:
We performed a retrospective study to determine
the effect of osteoporosis on the functional outcome of osteoporotic
distal radial fractures treated with a volar locking plate. Between
2009 and 2012 a total of 90 postmenopausal women with an unstable
fracture of the distal radius treated with a volar locking plate
were studied. Changes in the radiological parameters of 51 patients
with osteoporosis (group 1, mean age 66.9, mean T-score –3.16 ( We found that osteoporosis does not have a negative effect on
the functional outcome and additional analysis did not show a correlation
between T-score and outcome. Cite this article:
Although gradual bone transport may permit the
restoration of large-diameter bones, complications are common owing
to the long duration of external fixation. In order to reduce such
complications, a new technique of bone transport involving the use
of an external fixator and a locking plate was devised for segmental
tibial bone defects. A total of ten patients (nine men, one woman) with a mean age
at operation of 40.4 years (16 to 64) underwent distraction osteogenesis
with a locking plate to treat previously infected post-traumatic
segmental tibial defects. The locking plate was fixed percutaneously
to bridge proximal and distal segments, and was followed by external fixation.
After docking, percutaneous screws were fixed at the transported
segment through plate holes. At the same time, bone grafting was
performed at the docking site with the external fixator removed. The mean defect size was 5.9 cm (3.8 to 9.3) and mean external
fixation index was
13.4 days/cm (11.8 to 19.5). In all cases, primary union of the
docking site and distraction callus was achieved, with an excellent
bony result. There was no recurrence of deep infection or osteomyelitis,
and with the exception of one patient with a pre-existing peroneal
nerve injury, all achieved an excellent or good functional result. With short external fixation times and low complication rates,
bone transport with a locking plate could be recommended for patients
with segmental tibial defects. Cite this article:
We investigated the spinopelvic morphology and
global sagittal balance of patients with a degenerative retrolisthesis
or anterolisthesis. A total of 269 consecutive patients with a degenerative
spondylolisthesis were included in this study. There were 95 men
and 174 women with a mean age of 64.3 years ( A backward slip was found in the upper lumbar levels (mostly
L2 or L3) with an almost equal gender distribution in both the R
and R+A groups. The pelvic incidence and sacral slope of the R group
were significantly lower than those of the A (both p <
0.001)
and R+A groups (both p <
0.001). The lumbar lordosis of the R+A
group was significantly greater than that of the R (p = 0.025) and
A groups (p = 0.014). The C7 plumb line of the R group was located
more posteriorly than that of the A group (p = 0.023), but was no
different from than that of the R+A group (p = 0.422). The location
of C7 plumb line did not differ between the three groups (p = 0.068).
The spinosacral angle of the R group was significantly smaller than
that of the A group (p <
0.001) and R+A group (p <
0.001). Our findings imply that there are two types of degenerative retrolisthesis:
one occurs primarily as a result of degeneration in patients with
low pelvic incidence, and the other occurs secondarily as a compensatory
mechanism in patients with an anterolisthesis and high pelvic incidence. Cite this article:
To establish relative fixation strengths of a single lateral locking plate, a double locking plate, and a tibial nail in treatment of proximal tibial extra-articular fractures. Three groups of composite tibial synthetic bones consisting of 5 specimens per group were included; lateral plating (LP) using a LCP-PLT (locking compression plate-proximal lateral tibia), double plating (DP) using a LCP-PLT and a LCP-MPT (locking compression plate-medial proximal tibia), and intramedullary nailing (IN) using an ETN (expert tibial nail). To simulate a comminuted fracture model, a gap osteotomy measuring 1 cm was cut 8 cm below the joint. For each tibia, a minimal preload of 100N was applied before loading to failure. A vertical load was applied at 25mm/min until tibia failure.Background
Methods
Although gradual bone transport may provide a large-diameter bone, complications are common with the long duration of external fixation. To reduce such complications, a new technique of bone transport with a locking plate has been done for tibial bone defect. In 13 patients (mean age, 38.9 years) of chronic osteomyelitis or traumatic bone defect, segmental transport was done using external fixator with a locking plate. In surgical technique, a locking plate was fixed submuscularly, holding the proximal and distal segments. Then, the external fixator for transport was fixed without contact of the locking plate. After docking, 2 or 3 screws were fixed at the transported segment through the plate holes. At the same time, the external fixator was removed.Background
Methods
To evaluate outcome after cementless bipolar hemiarthroplasties using a standard(tapered, rectangular) stem for the treatment of above type A2 fractures in elderly patients. We reviewed the records of 37 patients who underwent bipolar hemiarthroplasty between February 2006 and Feburuary 2010 in our hospital who were followed for more than two years after surgery. The mean patient age was 73.5 years old (range 64∼88 years old). 16 patients were men, and 21 patients were women. We evaluated the results by analyzing operation time, amount of bleeding, recovery of walking ability, complications and radiologic findings.Purpose
Material and methods
A seventy-five-year-old female patient presented with pain and deformity of her left leg of three days duration. Hybrid THRA has been done 11 years ago at her left hip for the treatment of osteoarthritis. Massive osteolysis and pathologic fracture were observed on plain radiograph (Fig. 1). Revision THRA using an allograft prosthesis composite (APC) was planned for solution of extensive bone loss of the proximal femur. Surgical exposure was performed through extended trochanteric osteotomy with the patient supine. Step-cut osteotomy was done at the remained proximal part of host femur to make match with the distal part of APC. Meticulous removal of granulation tissues and remaining cement was done. As Acetabular cup was stable, 60 mm sized high-walled polyethylene liner was exchanged. Calcar reconstruction prosthesis was cemented into a proximal femoral allograft measuring 15 cm and cement at the vicinity of the step-cut osteotomy was removed for later bony union at interface. After solid fixation of APC with cement, the distal half of APC was cemented with the host femur. Step-cut osteotomy was wired and autogenous bone grafts from the greater trochanter were added at the interface. Leg length and stability were rechecked using a standard necked 28 mm metal head and reduction was done stably. Greater trochanter was fixed over the trimmed proximal allograft with multiple wiring and paper-thin host femur was enveloped around the femoral allograft using absorbable sutures. Following insertion of the closed suction drainage drains, closure was done as routine fashion and healing of the wound was uneventful (Fig. 2). An abduction brace was applied post operatively for a period of four weeks. Crutch walking with partial weight bearing was started at four weeks and crutch protection was applied for a period of six months. Incorporation of allograft with the host bone was observed on two-year follow-up radiographs. At seven-year follow-up, the patient walks well with a mild limp, and Harris score is 90. We report on a seven-year follow-up case of revision THRA with APC with references (Fig. 3).
To analyze the effectiveness of a vancomycin impregnated calcium sulfate cement bead insertion after debridement (of) an acute-immediate stage infected hip arthroplasty. Between 2002 and 2008, 13 patients with documented acute-immediate stage infection of hip arthroplasty were reviewed and followed for at least two years postoperatively(average 4.3 years). The preoperative and postoperative clinical and radiologic findings and blood laboratory work were checked. All cases were performed through retention of the implant and massive debridement and saline irrigation. After that a vancomycin impregnated calcium sulfate cement beads was inserted.Purpose
Materials and Methods
Recent reports about the excellent clinical results of unicondylar knee arthroplasty (UKA; also known as unicompartmental knee arthroplasty), by the minimally invasive approach, have encouraged the adoption of the surgical technique. However, friction between metallic prosthetic components resulting from polyethylene wear may result in the development of metallosis and the use of metal implants has become a huge issue in the worlds recently. Here, we report a case in which a patient underwent UKA and developed metallosis in soft tissues and bone adjacent to an implanted artificial joint three years postoperatively.
The posterior-stabilized knee prosthesis is designed specifically to provide the posterior stability to a knee arthroplasty when PCL is deficient or has to be sacrificed. Posterior dislocation of such prosthesis is rare but dreaded complication. There are several causes of postoperative dislocation such as malposition of the prosthesis, preoperative valgus deformity, a defect of the extensor mechanism and overwidening of the flexion gap. Posterior-stabilized rotating-platform mobile-bearing knee implants have been widely used to further improve the postoperative range of motion by incorporation of the post and cam mechanism to improve the posterior roll back during flexion and to overcome the wear and osteolysis problems due to significant undersurface micromotion of posterior-stabilized fixed-bearing knees. But, spin-out or rotatory dislocation of the polyethylene insert can occurs as result of excessive rotation of the rotating platform accompanied by translation of the femur on the tibia after mobile-bearing total knee arthroplasty, but that is very rare. Here, authors describe an unusual case of acute 180° rotatory dislocation of the rotating platform after posterior dislocation of a posterior-stabilized mobile-bearing total knee arthroplasty. A 71-year-old male with knee osteoarthritis underwent a TKRA using posterior-stabilized mobile-bearing prosthesis. The posterior dislocation of the total knee arthroplasty occurred 5 weeks postoperatively(Fig. 1). We underwent closed reduction of posterior dislocated total knee arthroplasty resulting in a complete 180° rotatory dislocation of the rotating platform (Fig. 2). He was treated with open exploration and polyethylene exchange with a larger component. This case illustrates that dislocation of a posterior-stabilized mobile-bearing total knee arthroplasty can occur with valgus laxity, cause 90° spin-out of the polyethylene insert and closed reduction attempts may contribute to complete 180° rotatory dislocation of the rotating platform. Special attention needs to be paid to both AP and lateral view to ensure that the platform is truly reduced and not just rotated 180° as was in this case.
We report the incidence and intensity of persistent
pain in patients with an otherwise uncomplicated total ankle replacement
(TAR). Arthroscopic debridement was performed in selected cases
and the clinical outcome was analysed. Among 120 uncomplicated TARs, there was persistent pain with
a mean visual analogue scale (VAS) of 2.7 (0 to 8). The intensity
of pain decreased in 115 ankles (95.8%). Exercise or walking for
more than 30 minutes was the most common aggravating factor (62
ankles, 68.1%). The character of the pain was most commonly described
as dull (50 ankles, 54.9%) and located on the medial aspect of the
joint (43 ankles, 47.3%). A total of seven ankles (5.8%) underwent subsequent arthroscopy.
These patients had local symptoms and a VAS for pain ≥ 7 on exertion.
Impingement with fibrosis and synovitis was confirmed. After debridement,
the median VAS decreased from 7 to 3 and six patients were satisfied.
The median VAS for pain and the American Orthopaedic Foot and Ankle
Society score of the ankles after debridement was similar to that
of the uncomplicated TARs (p = 0.496 and p = 0.066, respectively). Although TAR reduces the intensity of pain, residual pain is
not infrequent even in otherwise uncomplicated TARs and soft-tissue
impingement is the possible cause. Cite this article:
The purpose of this study was to evaluate the
risk of late displacement after the treatment of distal radial fractures with
a locking volar plate, and to investigate the clinical and radiological
factors that might correlate with re-displacement. From March 2007
to October 2009, 120 of an original cohort of 132 female patients
with unstable fractures of the distal radius were treated with a
volar locking plate, and were studied over a follow-up period of
six months. In the immediate post-operative and final follow-up
radiographs, late displacement was evaluated as judged by ulnar
variance, radial inclination, and dorsal angulation. We also analysed
the correlation of a variety of clinical and radiological factors
with re-displacement. Ulnar variance was significantly overcorrected
(p <
0.001) while radial inclination and dorsal angulation were
undercorrected when compared statistically (p <
0.001) with the unaffected
side in the immediate post-operative stage. During follow-up, radial
shortening and dorsal angulation progressed statistically, but none
had a value beyond the acceptable range. Bone mineral density measured
at the proximal femur and the position of the screws in the subchondral
region, correlated with slight progressive radial shortening, which
was not clinically relevant. Volar locking plating of distal radial fractures is a reliable
form of treatment without substantial late displacement. Cite this article:
The purpose of this study was to measure the
radiological parameters of femoral component alignment of the Oxford
Phase 3 unicompartmental knee replacement (UKR), and evaluate their
effect on clinical outcome. Multiple regression analysis was used
to examine the relative contributions of the radiological assessment
of femoral component alignment in 189 consecutive UKRs performed
by a single surgeon. The American Knee Society scores were compared
between groups, defined as being within or outside recommended tolerances
of the position of the femoral component. For the flexion/extension
position 21 UKRs (11.1%) lay outside the recommended limits, and for
posterior overhang of the femoral component nine (4.8%) lay outside
the range. The pre-operative hip/knee/ankle (HKA) angle, narrowest
canal distance from the distal femoral entry point of the alignment
jig and coronal entry-point position had significant effects on
the flexion/extension position. Pre-operative HKA angle had a significant
influence on posterior overhang of the femoral component. However,
there was no significant difference in American Knee Society scores
relative to the position of the femoral component.
No study compared the clinical results of the posterior-stabilized mobile-bearing knee with those of nonposterior-stabilized mobile-bearing knee in the same patients. The purpose of this study was to examine whether the clinical and radiographic results, range of motion, patients satisfaction, and complication rates would be better in the knees with a posterior-stabilized mobile-bearing knee than in the knees with a nonposterior-stabilized mobile-bearing knee. One hundred and fourteen patients (mean age, 67.9 years) received a nonposterior-stabilized mobile-bearing knee prosthesis in one knee and a posterior-stabilized mobile-bearing knee prosthesis in the contralateral knee. Seven patients were men, and 107 were women. At the time of each follow-up (mean, 7.3 years; range, seven to 7.6 years), the patients were assessed clinically and radiographically.Background
Methods
Total Knee Arthroplasty (TKA) is a durable procedure which allows most patients to achieve a satisfactory functional level, but there can be instability under stressful conditions. Instability is one cause of early revision, often due to misalignment or inadequate ligament balancing. Persistent instability may cause elevated polyethylene wear. Lower levels of instability may cause patient discomfort with certain stressful activities. Hence quantifying instability may have an important role in the functional evaluation of TKA. Several previous studies showed that accelerometers have advantages in kinematic studies including low cost, ease of application, and application to any activity. The aim of this study was to demonstrate the use of an accelerometer attached to the anterior of the tibia, as an evaluation of knee stability of TKA patients. It was postulated that accelerations between TKAs and normal controls will be different, which could indicate abnormal TKA kinematics involving instability, especially for high intensity activities. We tested 38 TKA knees in 27 patients, in the age range of 50–80 years, with a minimum follow up of 6 months; and 25 knees in 16 shoulder patients, who had no known knee pathology as age-matched controls. A tri-axial accelerometer was firmly attached to the anterior proximal tibia to measure 3-axis accelerations with a sample rate of 100 Hz. Four activities were tested; Starting with the test leg, walk 3 steps then come to a sudden stop Take one step forward with the non-tested leg and make a tight 90∗∗∗∗∗ turn towards the non- tested knee direction Sit down for 3–4 seconds then stand back up Step up on a 7″ inches high box with the test leg, followed by the non-test leg. Then step down from the box with the test leg, followed by the non-test leg. During the activities, the patients responded to a questionnaire on instability and pain for each activity. For each test at the time of foot impact, there was a high/low peak acceleration, the peak-to-valley being taken as the indicator. The mean total magnitude of the acceleration was compared between the TKA and control groups in the anterior-posterior direction using the Student's t-test. Statistical significance was at p-value < 0.05.INTRODUCTION
METHODS & MATERIALS
Despite many claims of good wear properties following
total knee replacement (TKR) with an oxidised zirconium (OxZr) femoral
component, there are conflicting clinical results. We hypothesised
that there would be no difference in either the mid-term clinical
and radiological outcomes or the characteristics of the polyethylene
wear particles (weight, size and shape) in patients using an OxZr
or cobalt-chrome (CoCr) femoral component. In all 331 patients underwent
bilateral TKR, receiving an OxZr femoral component in one knee and
a CoCr femoral component in the other. The mean follow-up was 7.5
years (6 to 8). Following aspiration, polyethylene wear particles
were analysed using thermogravimetric methods and scanning electron
microscopy. At the most recent follow-up, the mean Knee Society
score, Western Ontario and McMaster Universities Osteoarthritis
Index score, range of movement and satisfaction score were not significantly
different in the two groups. The mean weight, size, aspect ratio
and roundness of the aspirated wear particles were similar for each
femoral component. Survivorship of the femoral, tibial and patellar
components was 100% in both groups. In the absence of evidence of an advantage in the medium term
we cannot justify the additional expense of an OxZr femoral component.
It has been suggested that the wear of ultra-high molecular weight polyethylene (UHMWPE) in total hip replacement is substantially reduced when the femoral head is ceramic rather than metal. However, studies of alumina and zirconia ceramic femoral heads on the penetration of an UHMWPE liner in vivo have given conflicting results. The purpose of this study was to examine the surface characteristics of 30 alumina and 24 zirconia ceramic femoral heads and to identify any phase transformation in the zirconia heads. We also studied the penetration rate of alumina and zirconia heads into contemporary UHMWPE liners. The alumina heads had been implanted for a mean of 11.3 years (8.1 to 16.2) and zirconia heads for a mean of 9.8 years (7.5 to 15). The mean surface roughness values of the explanted alumina heads (Ra 40.12 nm and Rpm 578.34 nm) were similar to those for the explanted zirconia heads (Ra 36.21 nm and Rpm 607.34 nm). The mean value of the monoclinic phase of two control zirconia heads was 1% (0.8% to 1.5%) and 1.2% (0.9% to 1.3%), respectively. The mean value of the monoclinic phase of 24 explanted zirconia heads was 7.3% (1% to 26%). In the alumina group, the mean linear penetration rate of the UMWPE liner was 0.10 mm/yr (0.09 to 0.12) in hips with low Ra and Rpm values (13.22 nm and 85.91 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.13 mm/yr (0.07 to 0.23) in hips with high Ra and Rpm values (198.72 nm and 1329 nm, respectively). This difference was significant (p = 0.041). In the zirconia head group, the mean linear penetration rate of the UHMWPE liner was 0.09 mm/yr (0.07 to 0.14) in hips with low Ra and Rpm values (12.78 nm and 92.99 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.12 mm/yr (0.08 to 0.22) in hips with high Ra and Rpm values (199.21 nm and 1381 nm, respectively). This difference was significant (p = 0.039). The explanted zirconia heads which had a minimal phase transformation had similar surface roughness and a similar penetration rate of UHMWPE liner as the explanted alumina head.
Although total knee arthroplasty (TKA) has been a reliable procedure providing durable pain relief, polyethylene (PE) wear remains a major limitation of the long-term success of TKA. One potential method of lowering PE wear in TKA is to use oxidized zirconium (OxZr)-bearing surface. Although wear simulating testing of an OxZr counter surface of femoral component produced less PE wear and fewer particles than did cobalt-chrome (Co-Cr) counter surface of femoral component [1–4], this finding has not been demonstrated in vivo to our knowledge. We measured in vivo PE wear by isolating and analyzing PE wear particles in synovial fluid from wellfunctioning TKA [5]. The purpose of the current study was to determine the size, shape, and amount of PE wear particles isolated from synovial fluid of patients who underwent a bilateral simultaneous TKA prosthesis, but different materials of femoral components. We performed a bilateral simultaneous TKA in 100 patients (200 knees) who received an OxZr femoral component in one knee and a Co-Cr femoral component in the other. Mean age was 55.6 (44–60) years. Synovial fluid was obtained from 28 patients (56 knees) who had undergone a simultaneous bilateral TKA under completely sterile conditions at one or two years after the operation. Randomization to an OxZr or Co-Cr femoral component was accomplished with use of a sealed study number envelope, which was opened in the operating room before the skin incision had been made. After the opening the randomization envelope, the first knee received prosthesis indicated by the envelope (OxZr or Co-Cr component) and the contralateral (second TKA) knee received the other prosthesis (OxZr or Co-Cr component). All operations were performed by one surgeon using the same design of total knee prosthesis: Genesis II (Smith and Nephew, Memphis, Tennessee). Only the material of the femoral component differed between two groups. The preoperative diagnosis was osteoarthritis in all patients. Preoperative and post operative KS and HSS knee scores, KS functional scores and UCLA activity scores were evaluated. The amount of polyethylene wear particles in the aspirated synovial fluid sample was analyzed by thermogravimetic analysis (TGA) using a TGA instrument (TGA/SDTA 84le model, Mettler Toledo CO., Greifensee, Switzerland). The weight of the sample solution was measured before and after removing the organic content by heating the sample solution. The sample solution was casted onto petri dishes. The petri dish was covered and kept in a dry oven at 60°C for 2 days. While the sample solution was kept in a dry oven for 2 days, a small hole was made on the cover of the petri dish to allow water to evaporate slowly for 2 days. After this procedure, the cover of petri dish was removed and TGA sample was dried at 60°C for another 2 days. After the sample was completely dried out, the dried sample was measured using analytical balance. TGA was used to determine the weight change profiles of polyethylene subject to heating under a nitrogen atmosphere. The nitrogen flow rate was kept constant at 50mL per minute. TGA data were taken at heating rate as 5°C per minute in the temperature range of 20° to 1000°C. The weight loss data were recorded as a function of time and temperature using special software in computer. When the temperature reached to the point of decomposition of the sample, the sample started to lose weight. By calculating the weight of the sample around the temperature which led to start to decomposition, real amount of polyethylene in the sample was measured. The size and shape of PE particles were examined using scanning electron microscopy (JSH-6360A model, Jeol Co., Tokyo, Japan). The samples were coated using a platinum sputtering machine for 20 sec. ANOVA, nonparametric chi square test, nonpaired t-test and Mann-Whitney U-test were used for statistical analyses. Differences of P<
0.05 were considered statistically significant. Mean preoperative KS (27.5 vs 27.2 points) scores, HSS (51.1 vs 51.2 points) knee scores, KS functional scores (55.4 vs 55.4 points) and UCLA activity scores (2.8 vs 2.8 point) were not significantly different between two groups. Mean postoperative KS (93 vs 92 points), HSS knee scores (90 vs 89 points), KS functional scores (78 vs 78 points), and UCLA activity scores (7.8 vs 7.8) were not significantly different. Mean weight of the polyethylene particles was 0.0219 g (SD, 0.0058) in the Co-Cr femoral component groups and it was 0.0214 g (SD, 0.005) in the OxZr group. This difference was not significant (P=0.711139, paired t-test). The size of particles was not different between the two groups. Also, shape of particles was not different between the two groups. Under the condition and the duration of this study in this specific group of patients, TKA with OxZr or Co-CR femoral knee component had excellent clinical and radiographic outcomes with no osteolysis. While the wear simulator test in vitro demonstrated significant decrease in PE particles in the knees with an OxZr femoral component, our study in vivo revealed that total particle weight, size, and shape of PE wear particles were similar in the knees with an OxZr femoral component and in those with a Co-Cr femoral component.