Measurement of periprosthetic bone mineral density after cementless hip arthroplasty by dual energy X-ray absorptiometry: Longitudinal and cross-sectional evaluation

To clarify changes in bone mass around a femoral prosthesis, periprosthetic bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) in 60 patients after unilateral cementless hip arthroplasty. Changes in BMD were evaluated by cross-sectional analysis in all patients and by longitudinal analysis in 26 patients who were available for measurement from 1 month to 2 years after surgery. The mean reproducibility of BMD measurements was within 1.74% in vivo. Periprosthetic BMD began to decrease early after surgery, and although it recovered temporarily within 1 year, it did not return to the level of the 1st month even after 2 years. BMD was reduced by 30.4% in the whole periprosthetic region compared with the contralateral untreated femora 4–7 years after surgery. The reduction in BMD was remarkable around the proximal part of the stem, especially in zone 7 (44.7% reduction 4–7 years after surgery). Significant positive correlations were observed between the low level of the preoperative cortical remodelling index and the reduction in BMD and between the preoperative femoral BMD and the reduction in BMD, indicating that the postoperative bone loss was greater in patients who preoperatively showed quantitative and qualitative deterioration of the femur. Abstracts of this paper were presented at the 66th and 67th Annual Meeting of the Japanese Orthopaedic Association, the 19th Conference of Société Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT), and the 20th Conference of the Japanese Hip Society     

Midterm radiographic comparison of cementless acetabular shells containing lateralized and nonlateralized liners

This retrospective study assessed the effect of lateralized acetabular inserts on polyethylene wear rates, radiographic loosening, and hip stability. Fifty-six 4-mm lateralized liners and 39 neutral liners were compared at a mean follow-up of 7.1 years. Multivariate regression analysis demonstrated a significant increase of 0.04 mm/y in polyethylene wear rate with use of lateralized liners. However, predictable cementless fixation was obtained without screws in both liner groups with no migration or radiographic signs of loosening observed for any cup. The dislocation rate for hips with lateralized liners (3.6%) was less than that for hip with neutral liners (10.3%), although the difference was not significant with the numbers available. Despite the increase in wear rate, hips with lateralized liners performed as well as those with neutral liners with regard to loosening and stability.     

Straight tapered titanium stem with alumina bearing in cementless primary total hip arthroplasty: a minimum 5-year follow-up

The aim of this study was to assess the midterm results of primary cementless total hip arthroplasty using a tapered stem and alumina bearing couple in active patients. After a minimum of 5 years of follow-up, 78 arthroplasties in 72 patients were reviewed retrospectively. The mean Harris hip score was 94 points, and 2 hips had thigh pain. All components radiographically demonstrated stable fixation by bone ingrowth and mild stress shielding of the proximal femur were noted in 14% of hips. There was no significant osteolysis or aseptic loosening. There was a ceramic head fracture in 1 hip and audible sounds in 2 hips. The results of total hip arthroplasty with a straight, tapered, proximally porous-coated stem and alumina-on-alumina bearing were encouraging for active patients.     

Uncemented Total Knee Arthroplasty: 2-Year Follow-Up of 100 Knees With a Rotating Platform, Cruciate-Retaining Design

Review of the literature shows mixed results regarding uncemented total knee arthroplasty (TKA). To our knowledge, there are no reports of results for uncemented TKA that incorporates a cruciate-retaining and rotating platform design. It is theorized that these design features could decrease the stress at the bone-implant interface. This study reports results on 100 uncemented TKAs at a minimum of 2-year follow-up. Average Knee Society clinical score improved from 52.9 to 95.1; average Knee Society functional score improved from 60.5 to 82.0. Ninety-eight percent of patients had excellent and 2% had good results based on Knee Society scores. There was 99% implant survival; 1 patient required revision of a loose tibial component after a motor vehicle accident. The promising short-term results support the continued use of this implant and suggest a prospective randomized study comparing cemented vs uncemented TKA of this design is warranted.     

Management of Failed Trochanteric Fracture Fixation With Cementless Modular Hip Arthroplasty Using a Distally Fixing Stem

Failure of internal fixation of intertrochanteric fractures is associated with delayed union or malunion resulting in persistent pain and diminished function. We evaluated 15 elderly patients treated with a tapered, fluted, modular, distally fixing cementless stem. At an average follow-up of 2.86 years, mean Harris hip score improved from 35.90 preoperatively to 83.01 (P < .01). Fourteen stems had stable bony ongrowth, and one stem was loose. Distal fixation with a tapered, fluted, modular cementless stem allows stable fixation with good functional outcome in a reproducible fashion in this challenging cohort of patients.     

Midterm results of a porous tantalum monoblock tibia component clinical and radiographic results of 108 knees

The use of Trabecular Metal (TM), a biomaterial manufactured from elemental tantalum metal, has recently increased in orthopedics. One hundred eight consecutive TM monoblock tibias were implanted in 95 patients and followed for a minimum of 2 years. The average follow-up was 4.5 years. The average age was 65 years. The Knee Society score of 36 improved to 89. One hundred five of the knees were rated good/excellent, and 3 knees were rated poor. Two patellar revisions were performed for loose components and one for patellar misalignment. One patella fracture required open reduction and internal fixation. One femur was revised. There were no tibia revisions. There were no progressive radiographic lucencies. Midterm clinical and radiographic results of 108 consecutive TM tibia components have a high rate of success.     

Total Hip Arthroplasty With an Uncemented Tapered Femoral Component in Patients Younger than 50 Years

The purpose of the present study was to evaluate the outcome of primary uncemented total hip arthroplasty in patients younger than 50 years using the Taperloc (Biomet, Warsaw, Ind) femoral component. We evaluated 94 hips in 79 patients at a mean follow-up of 16 years (range, 11-18.5 years). The average age of the patients at the time of surgery was 36 years (range, 20-49 years). Three femoral components had been revised, none for aseptic loosening. Complete clinical and radiographic follow-up was obtained on the 91 hips that had not undergone femoral component revision. The mean Harris hip score increased from 54 points (range, 20-72) before surgery to 93 points (range, 68-100) at the time of this review. Radiographically, 89 stems (98%) were determined to have fixation by bone ingrowth, 2 (2%) demonstrated stable fibrous ingrowth, and no femoral component was loose. Distal femoral osteolysis was identified in 1 hip (1%). These findings indicate that excellent clinical and radiographic results can be achieved in young patients with the Taperloc femoral component at a mean follow-up of 16 years.     

Cementless Bipolar Hemiarthroplasty Using a Hydroxyapatite-Coated Long Stem for Osteoporotic Unstable Intertrochanteric Fractures

Treating senile osteoporotic patients with unstable hip fractures remains a challenge. We evaluated the results of 87 cementless bipolar hemiarthroplasties using an extensively hydroxyapatite-coated long stem for unstable intertrochanteric fractures in senile patients. Sixty-one hips were followed for a minimum of 2 years (mean, 36 months) postoperatively. The mean Merle d'Aubigne and Postel hip score was 14.7 points (12-18). Two hips were reoperated because of infection. Of the remaining 59 hips, 48 were included in the radiographic analysis. Although cortical porosis around the stem was seen in 18 hips, there was no loosening or osteolysis. Cementless bipolar hemiarthroplasty using an extensively hydroxyapatite-coated long stem is a useful option for the treatment of unstable intertrochanteric fracture in senile patients with severe osteoporosis.     

Cementless two-stage exchange arthroplasty for infection after total hip arthroplasty

We retrospectively reviewed all patients at one center with an infected total hip arthroplasty treated with 2-stage revision using cementless components for the second stage and the PROSTALAC articulated spacer at the first stage. Twenty-nine patients were reviewed and followed for at least 2 years postoperatively. An isolated Staphylococcus species was cultured in 76% (22/29) of patients. Three (10.3%) of 29 patients had recurrent infection at the site of the prosthesis. One of the 3 patients ultimately underwent a Girdlestone arthroplasty. Another patient was managed with irrigation and debridement, whereas the final patient was treated with intravenous antibiotics alone. Treatment of infection at the site of a hip arthroplasty with 2-stage revision using cementless components and an articulated spacer yields recurrence rates similar to revisions where at least one of the components at the second stage is fixed with antibiotic-loaded cement.     

Catastrophic failure of cementless total hip arthroplasty using a femoral component without surface coating

Consecutive series of 90 hips that had had a primary cementless arthroplasty with use of straight collarless stems between January 1988 and September 1992 were reviewed. Twenty-eight hips with Omnifit Normalized Stems (Fit-N) and 45 hips with Omniflex Normalized Stems (Flex-N) without porous coatings were compared clinically and radiographically with 17 hips with Omnifit Microstructured Stems (Fit-M) with porous coating. The average follow-up periods for the 3 stems were 97 months, 73 months, and 93 months. Revision was performed or awaited in 9 cases (32.1%) in the Fit-N group, 18 cases (40.0%) in the Flex-N group, and 1 case (5.8%) in the Fit-M group. The average annual subsidence was 0.62 mm/y, 0.73 mm/y, and 0.17 mm/y. Osteolysis of more than 3 mm occurred in 28.6%, 37.8%, and 23.5%. Fit-N stems and Flex-N stems without porous coatings are not appropriate for cementless total hip arthroplasty.