Early Tibial Component Fractures in a Cementless, 3D-Printed, Titanium Implant.

Fracture of the tibial baseplate in total knee arthroplasty is a rare occurrence, particularly in short- and mid-term follow-up. This case series documents the first known report in the literature of fatigue fracture of a cementless, 3D-printed, highly porous titanium tibial component. We recommend regular follow-up visits with radiographs to confirm adequate total knee arthroplasty component positioning and alignment.

A new technique for articulated cement spacers in infected total knee arthroplasty.

Chronically infected total knee arthroplasty (TKA) represents a surgical challenge with many potential complications. The standard of care is a 2-stage reimplantation. This report describes a modification of the first stage using the protocol described by Hofmann and colleagues in 1995. This modification was developed by the senior author (GPD) in response to episodes of tibial subluxation and postoperative instability detected between the first and second stages. This modification utilizes a rotating platform all polyethylene tibial component insert with a keel that offers a more stable construct which allows increased stability of the component. Employing this technique, we have had good clinical results with an average knee flexion of 105º, no cases of tibial component migration or subluxation, or recurrence of infection.

Maximizing surgeon and hospital total knee arthroplasty volume using customized patient instrumentation and swing operating rooms.

To meet the needs of increasing demand for total knee arthroplasty, the individual surgeon must focus on improving proficiency and volume. Improved efficiencies in total joint arthroplasty (TJA) have many benefits beyond meeting the increasing demand by patients for joint replacement, however. Surgeons and institutions that perform a higher volume of TJAs have lower rates of mortality, complications, and readmissions compared with surgeons and institutions that perform a lower volume of TJAs. Surgeons and hospitals must commit to the resources that can improve their TJA volume and, in turn, their overall TJA outcomes. Implementing "swing," or parallel, operating rooms, dedicating the surgeon to performing the TJA procedure only, and utilizing customized patient instrumentation to identify ideal surgery scheduling practices and to decrease surgical time can increase performance and patient satisfaction.

Hip resurfacing arthroplasty: risk factors for failure over 25 years.

UNLABELLED: Many early metal-on-polyethylene hip resurfacing arthroplasty designs were abandoned after reports of high short-term and midterm failure rates. To investigate factors associated with failure, we retrospectively reviewed our experience with early-design hip resurfacing implants in 75 patients during a 25-year period (median followup, 7.9 years; range, 0.1-25.2 years). Implant failure was defined as revision for any reason. One of 75 patients was lost to followup. The estimated rate of implant survival was 73% at 5 years, 34% at 10 years, 27% at 15 years, 12% at 20 years, and 8% at 25 years. Of the many clinical and radiographic factors considered, only age, implant type, and gender were associated with implant survival independent of other variables considered. Hip resurfacing arthroplasty showed poor overall long-term survival in this series. Particular attention should be paid to the identified risk factors as long-term followup data become available for modern designs. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fracture of a cross-linked polyethylene liner due to impingement.

We report a case of fracture at 2 years after implantation of a 50-kGy moderately cross-linked ultrahigh molecular weight polyethylene liner with an extended lip (Marathon, DePuy, Warsaw, IN). The extended lip section had fractured. The liner showed no oxidation. The articular surface was grossly deformed, likely due to wear, creep, and/or plastic deformation, and the liner showed no recovery of machining marks upon melting, indicating that some wear had occurred. Electron microscopy revealed fatigue striations on the fracture surface. The likely cause of failure was femoral neck impingement-induced wear and fatigue on the liner.

Use of a custom stemless anatomic femoral component for an incarcerated femoral reamer.

Most modern femoral components used in total hip arthroplasty have stems that engage a certain length of the femoral diaphysis. Retained hardware can pose a problem with placement of the femoral component during total hip arthroplasty and often require removal. A patient presented for total hip arthroplasty with a retained reamer in the proximal femur from a previous revision knee arthroplasty. The reamer's position precluded placement of a standard femoral component without removal of the reamer. We report the use of a stemless anatomical femoral component, which avoided having to remove the retained reamer.

Impaction grafting using a cemented porous-coated modular acetabular component.

Reconstruction of major acetabular defects continues to challenge surgeons. There are many surgical options for these situations, including oversized hemispherical cups, oblong cups, acetabular cages, bulk allografts, and impaction allografting. We present the case of a modification to the impaction grafting technique for acetabular reconstruction. In our case, a porous-coated modular titanium acetabular component was cemented in place instead of an all-polyethylene acetabular component, which is the standard technique for impaction grafting reconstruction. The use of the modular component allowed a greater number of surgical options at the time of surgery. At 5 years from surgery, the patient has a successful reconstruction and the radiographs continue to look excellent.

Hybrid total knee arthroplasty analysis of component failures at an average of 15 years.

Hybrid total knee arthroplasty in which the femoral component is cementless and the tibial component is cemented remains controversial. We report on the long-term results of 65 total knee arthroplasties followed for an average of 15 years. There were 18 revisions (27%); of these, 11 were femoral component revisions. The overall implant survival with revision as the end point was estimated as 64% at 15 years. The femoral component survivorship at 15 years was 72%. Because of the high failure rate, hybrid fixation on the femoral side with this design has been abandoned at our institution; but hybrid fixation with a trabecular metal tibia is currently under investigation.

Cemented total knee arthroplasty using a modern prosthesis in young patients with osteoarthritis.

Fifty-two consecutive cemented total knee arthroplasties were performed using the Press-Fit Condylar (DePuy, Warsaw, Ind) knee system on patients aged 55 years or younger at Mayo Clinic Rochester from 1988 to 1994. Patients were followed for a minimum of 10 years, with an average follow-up of 12 years (range, 10-15 years). There were 8 total revisions (15%), including 2 revisions before 10 years, one for sepsis at 1 year, and one for instability at 8 years. Six revisions occurred between 10 and 15 years, all associated with polyethylene wear and osteolysis. Implant survival rate was estimated to be 96% at 10 years and 85% at 15 years of follow-up.

Fatigue failure of the GAP ring.

This study reports the results and early failures using the Graft Augmentation Prosthesis ring in the reconstruction of acetabular defects encountered during total hip arthroplasty. Seventeen consecutive Graft Augmentation Prosthesis rings were used during 7 complex primary and 10 revision hip arthroplasties. Five patients died during the follow-up period. Of the remaining 12 patients, 7 had been revised at an average of 5 years follow-up. Five cases were revised because of fatigue failure of the implant associated with allograft resorption. Two cases were revised for recurrent dislocations. Because of this high mechanical failure rate (5 of 12 cases at only 5 years follow-up), we have abandoned this device in favor of implants with more mechanical strength.

Case report: Endometrioma of the abdominal wall.

We present the case of a 39-year-old woman with a 2- to 3-month history of a soft tissue mass involving the abdominal wall and increasing symptoms that fluctuated relative to her menses. Magnetic resonance imaging showed a hemorrhagic multiloculated mass within the rectus abdominus muscle. Correlation of the clinical history and imaging finding suggested a preoperative diagnosis of endometrioma of the abdominal wall. This was confirmed on histologic analysis of the resected specimen.

Polished vs rough femoral components in grade A and grade C-2 cement mantles.

The ideal surface for cemented femoral components remains controversial. Six polished stems were compared with 6 rough stems both with good cement mantle and also with poor cement mantles in a stair-climbing model. With good cement mantles, both the polished and the rough stems were loose by 6 million cycles. However, none were loose by radiographic criteria. With the poor cement mantle, both stems became loose earlier and developed more micromotion, the polished stems having significantly higher and earlier motion than the rough. Radiographic evidence of debonding was not visible until the stems had motion of more than 2,000 microm. In the presence of a good cement mantle in this laboratory model there was no significant difference in the development of micromotion under fatigue stair-climbing conditions between a polished or grit-blasted femoral component. However, in the presence of a poor cement mantle, the polished components had earlier and higher micromotion. This study reinforces the importance of centralization and cement technique, particularly if using a polished surface finish.

Surgical planning of total hip arthroplasty: accuracy of computer-assisted EndoMap software in predicting component size.

PURPOSE: The purpose of our study was to assess the accuracy of a computer-assisted templating in the surgical planning of patients undergoing total hip arthroplasty utilizing EndoMap software (Siemans AG, Medical Solutions, Erlangen, Germany). Endomap Software is an electronic program that uses DICOM images to analyze standard anteroposterior radiographs for determination of optimal prosthesis component size. METHODS: We retrospectively reviewed the preoperative radiographs of 36 patients undergoing uncomplicated primary total hip arthroplasty, utilizing EndoMap software, Version VA20. DICOM anteroposterior radiographs were analyzed using standard manufacturer supplied electronic templates to determine acetabular and femoral component sizes. No additional clinical information was reviewed. Acetabular and femoral component sizes were assessed by an orthopedic surgeon and two radiologists. Mean and estimated component size was compared with component size as documented in operative reports. RESULTS: The mean estimated acetabular component size was 53 mm (range 48-60 mm), 1 mm larger than the mean implanted size of 52 mm (range 48-62 mm). Thirty-one of 36 acetabular component sizes (86%) were accurate within one size. The mean calculated femoral component size was 4 (range 2-7), 1 size smaller than the actual mean component size of 5 (range 2-9). Twenty-six of 36 femoral component sizes (72%) were accurate within one size, and accurate within two sizes in all but four cases (94%). CONCLUSION: EndoMap Software predicted femoral component size well, with 72% within one component size of that used, and 94% within two sizes. Acetabular component size was predicted slightly better with 86% within one component size and 94% within two component sizes.

Long-term results of total knee arthroplasty in young patients with rheumatoid arthritis.

Forty-seven cemented total knee arthroplasties in 32 patients with rheumatoid arthritis who were 55 years or younger (average, 43) were followed until death or a minimum of 15 years. The average follow-up was 18 years. There were 6 revisions; 5 of 6 revisions had severe polyethylene wear and osteolysis. All revisions occurred after 17 years (range, 17-23). Three of these had fracture of the tibial component associated with polyethylene wear through; the remaining 2 had loose tibial and femoral components. One patient sustained a distal femoral periprosthetic fracture requiring revision of the total knee. Cemented total knee arthroplasty in the young patient with rheumatoid arthritis is reliable and durable at an average 18 years of follow-up with an estimated survivorship of 100% at 15 years and 93.7% at 20 years.

Primary uncemented Harris-Galante acetabular components in patients 50 years old or younger: results at 10 to 12 years.

Seventy-three patients (84 hips) 50 years or younger were treated with primary total hip arthroplasty using the Harris-Galante uncemented acetabular component. At a median followup of 10 years, there were seven acetabular metal shell revisions: five for osteolysis and one each for aseptic loosening and dislocation. There were 10 polyethylene exchanges without metal acetabular shell removal. None of the unrevised acetabular components was radiographically loose, but eight had pelvic osteolysis. The rate of 10-year survival without revision of the acetabular metal shell was 87.9% (95% confidence interval, 80.1%-95.7%). The same rate of survival without revision for aseptic acetabular component loosening was 97.3% (95% confidence interval, 92.9%-100%). Revision for aseptic acetabular loosening or polyethylene liner exchange or both was 84.5% (95% confidence interval, 75.8%-93.4%).