Berry, Daniel J.

Background: In the presence of a competing risk of death, the Kaplan-Meier method is known to overestimate the probability of implant failure. To our knowledge, the magnitude of the competing risk of death in survivorship analyses in total knee arthroplasty has not been studied. The purpose of this study was to determine the extent of the competing risk of death in different age groups during a long-term follow-up of patients who had undergone primary total knee arthroplasty. Methods: The study population comprised 22,864 primary total knee arthroplasties at a large medical center in the United States. We compared the overall revision outcomes estimated using the Kaplan-Meier method and the cumulative incidence function over a mean follow-up of 7.8 years (range, 0.1 to 26.3 years). Results: The risk of death exceeded the risk of revision by a factor of 4 at twelve years following the surgical procedure. The Kaplan-Meier method overestimated the risk of revision by 3% at five years, 14% at ten years, 32% at fifteen years, and 57% at twenty years. At ten years after the surgical procedure, the risk of death exceeded the risk of revision by a factor of 15 in the all-polyethylene group and by a factor of 3.5 in the metal modular group. The Kaplan-Meier method overestimated the ten-year risk of revision by 18% in the all-polyethylene group and by 11% in the metal modular group. After accounting for the higher competing risk of death in the all-polyethylene group, the cumulative incidence of revision in the metal modular group was about 2.5 to three times higher than that in the all-polyethylene group at ten years. Conclusions: Although the Kaplan-Meier and cumulative incidence methods yielded different implant survival estimates beyond ten years (Kaplan-Meier overestimates implant failure), the size of the bias was small at earlier time points. The extent of overestimation depends on the duration of follow-up and the magnitude of the competing risk of death. Clinical Relevance: This study examines the clinical relevance of the competing risk of death in total knee arthroplasty.

Aims The goals of this study were to define the risk factors, characteristics, and chronology of fractures in 5417 revision total hip arthroplasties (THAs). Patients and Methods From our hospital’s prospectively collected database we identified all patients who had undergone a revision THA between 1969 and 2011 which involved the femoral stem. The patients’ medical records and radiographs were examined and the relevant data extracted. Post-operative periprosthetic fractures were classified using the Vancouver system. A total of 5417 revision THAs were identified. Results There were 668 intra-operative fractures, giving an incidence of 12%. Fractures were three times more common with uncemented stems (19%) than with cemented stems (6%) (p < 0.001). The incidence of intra-operative femoral fracture varied by uncemented stem type: fully-coated (20%); proximally-coated (19%); modular fluted tapered (16%) (p < 0.05). Most fractures occurred during the insertion of the femoral component (35%). One-third involved the diaphysis and 26% were of the calcar: 69% were undisplaced. There were 281 post-operative fractures of the femur (20-year probability = 11%). There was no difference in risk for cemented and uncemented stems. Post-operative fractures were more common in men < 70 years (p = 0.02). Periprosthetic fractures occurred earlier after uncemented revision of the femoral component, but later after a cemented revision. The most common fracture type was a Vancouver B 1 (31%). Of all post-operative fractures, 24% underwent open reduction and internal fixation and 15% revision arthroplasty. Conclusion In revision THA, intra-operative fractures occurred three times more often with an uncemented stem. Many were undisplaced diaphyseal fractures treated with cerclage fixation. While the risk of post-operative fracture is similar between uncemented and cemented components, they occur at notably different times depending on the type of stem fixation. Take home message: In revision THA, intra-operative periprosthetic femoral fractures occur three times more often with uncemented stems. Many are non-displaced diaphyseal fractures treated with cerclage fixation. While postoperative fracture risks are equivalent between uncemented and cemented components, they occur at notably different time periods based on stem fixation type. Cite this article: Bone Joint J 2016;98-B:468–74.

Aim and Methods The goals of this study were to define the risk factors, nature, chronology, and treatment strategies adopted for periprosthetic femoral fractures in 32 644 primary total hip arthroplasties (THAs). Results There were 564 intra-operative fractures (1.7%); 529 during uncemented stem placement (3.0%) and 35 during cemented stem placement (0.23%). Intra-operative fractures were more common in females and patients over 65 years (p < 0.001). The majority occurred during placement of the femoral component (60%), and involved the calcar (69%). There were 557 post-operative fractures (20-year probability: 3.5%; 95% confidence interval (CI) 3.2 to 3.9); 335 fractures after placement of an uncemented stem (20-year probability: 7.7%; 95% CI 6.2 to 9.1) and 222 after placement of a cemented stem (20-year probability: 2.1%; 95% CI 1.8 to 2.5). The probability of a post-operative fracture within 30 days after an uncemented stem was ten times higher than a cemented stem. The most common post-operative fracture type was a Vancouver A G (32%; n = 135), with 67% occurring after a fall. In all, 36% (n = 152) were treated with revision arthroplasty. Conclusion In summary, intra-operative fractures occur 14 times more often with uncemented stems. Female patients over 65 years of age are at highest risk. Post-operative fractures are also most common with uncemented stems, but are independent of age or gender. Cumulative risk of post-operative periprosthetic femur fracture was 3.5% at 20 years. Take home message: Intra-operative fractures occur 14 times more often with uncemented stems, particularly with female patients over 65 years of age, while post-operative fracture risk is independent of age or gender, but still increased with uncemented stems. Cite this article: Bone Joint J 2016;98-B:461–7.

Revision total hip arthroplasty (THA) is challenging when there is severe loss of bone in the proximal femur. The purpose of this study was to evaluate the clinical and radiographic outcomes of revision THA in patients with severe proximal femoral bone loss treated with a fluted, tapered, modular femoral component. Between January 1998 and December 2004, 92 revision THAs were performed in 92 patients using a single fluted, tapered, modular femoral stem design. Pre-operative diagnoses included aseptic loosening, infection and peri-prosthetic fracture. Bone loss was categorised pre-operatively as Paprosky types III-IV, or Vancouver B3 in patients with a peri-prosthetic fracture. The mean clinical follow-up was 6.4 years (2 to 12). A total of 47 patients had peri-operative complications, 27 of whom required further surgery. However, most of these further operations involved retention of a well-fixed femoral stem, and 88/92 femoral components (97%) remained in situ. Of the four components requiring revision, three were revised for infection and were well fixed at the time of revision; only one (1%) was revised for aseptic loosening. The most common complications were post-operative instability (17 hips, 19%) and intra-operative femoral fracture during insertion of the stem (11 hips, 12%). Diaphyseal stress shielding was noted in 20 hips (22%). There were no fractures of the femoral component. At the final follow-up 78% of patients had minimal or no pain.Revision THA in patients with extensive proximal femoral bone loss using the Link MP fluted, tapered, modular stem led to a high rate of osseointegration of the stem at mid-term follow-up.Cite this article: Bone Joint J 2015; 97-B:312–17.

Abstract The role of human bone marrow (BM) CD8+ T cells in the immune response to viral Ags is poorly defined. We report here the identification and characterization of a functionally enhanced effector memory CD8+ T cell population (TEM) in the BM of patients undergoing total joint replacement for osteoarthritis. These BM-derived TEM differ strikingly from correlate cells in peripheral blood (PB), expressing elevated levels of CD27, HLA-DR, CD38, CD69, and unique patterns of chemokine receptors. Interestingly, while BM TEM have low levels of resting perforin and granzyme B, these molecules evidence profound up-regulation in response to TCR stimulation resulting in enhanced cytotoxic potential. Moreover, compared with the TEM subset in PB, BM CD8+ TEM cells demonstrate a more vigorous recall response to pooled viral Ags. Our results reveal that human BM serves as a repository for viral Ag-specific TEM with great therapeutic potential in vaccine development.

Total hip replacement (THR) after acetabular fracture presents unique challenges to the orthopaedic surgeon. The majority of patients can be treated with a standard THR, resulting in a very reasonable outcome. Technical challenges however include infection, residual pelvic deformity, acetabular bone loss with ununited fractures, osteonecrosis of bone fragments, retained metalwork, heterotopic ossification, dealing with the sciatic nerve, and the difficulties of obtaining long-term acetabular component fixation. Indications for an acute THR include young patients with both femoral head and acetabular involvement with severe comminution that cannot be reconstructed, and the elderly, with severe bony comminution. The outcomes of THR for established post-traumatic arthritis include excellent pain relief and functional improvements. The use of modern implants and alternative bearing surfaces should improve outcomes further. Cite this article: Bone Joint J 2013;95-B, Supple A:11–16.

This conversation represents an attempt by several arthroplasty surgeons to critique several abstracts presented over the last year as well as to use them as a jumping off point for trying to figure out where they fit in into our current understanding of multiple issues in modern hip and knee arthroplasty.

BACKGROUND: When surgeons perform total hip arthroplasty for hips with a high dislocation related to developmental dysplasia of the hip, obtaining long-term stable implant fixation and optimizing patient function remain challenges. The purpose of this paper was to evaluate the results of cementless arthroplasty with a simultaneous subtrochanteric shortening osteotomy in a group of patients with Crowe type-IV developmental dysplasia of the hip. METHODS: In a retrospective study, we evaluated the results and complications of twenty-eight consecutive primary cementless total hip arthroplasties in twenty-four patients (twenty women and four men), all of whom had Crowe type-IV developmental dysplasia of the hip. The arthroplasty was performed in combination with a subtrochanteric shortening osteotomy and with placement of the acetabular component at the level of the anatomic hip center. The patients were evaluated at a mean of 4.8 years postoperatively. RESULTS: The mean Harris hip score increased from 43 points preoperatively to 89 points at the time of final follow-up (p < 0.01). Twelve (43%) of the twenty-eight hips had an early or late complication or a reoperation. Two (7%) of the twenty-eight subtrochanteric osteotomies were followed by nonunion. There was one instance of isolated loosening of the femoral stem. One acetabular component loosened, and one acetabular liner disengaged. Four hips dislocated postoperatively. All remaining components were well-fixed at the time of the last radiographic follow-up. No sciatic neurapraxic injuries were identified. CONCLUSIONS: Cementless total hip arthroplasty combined with a subtrochanteric femoral shortening osteotomy in patients with a high hip dislocation secondary to developmental dysplasia was associated with high rates of successful fixation of the implants and healing of the osteotomy site and a mean postoperative Harris hip score of 89 points. The complication rate, however, was substantially higher than that associated with primary total hip arthroplasty in patients with degenerative arthritis. LEVEL OF EVIDENCE: Therapeutic Level IV . See Instructions to Authors for a complete description of levels of evidence. ORIGINAL ABSTRACT CITATION: “Total Hip Arthroplasty with Shortening Subtrochanteric Osteotomy in Crowe Type-IV Developmental Dysplasia” (2009;91:2213-21).

Background Prevention of thromboembolic complications after elective lower extremity arthroplasty has increasingly relied on routine thromboprophylaxis in all patients. Not all patients are at equal risk, however, and prophylaxis is not devoid of complications. The aim of this study was to examine the risk factors for clinically relevant pulmonary embolism and deep venous thrombosis after elective primary hip or knee arthroplasty in a large patient population. Methods During the 10-yr study period, 116 of 9,791 patients undergoing primary hip or knee arthroplasty at the authors' institution who experienced pulmonary embolism or deep venous thrombosis within 30 days of surgery were matched at a 1:1 ratio with patients undergoing the same surgery with the same surgeon who did not experience an adverse event. Medical records were reviewed, with data abstracted using a standardized data collection form. Results Increased body mass index (P = 0.031; odds ratio = 1.5 for each 5-kg/m2 increase) and American Society of Anesthesiologists physical status classification of 3 or greater (P = 0.005; odds ratio = 2.6) were found to independently increase the likelihood of pulmonary embolism or deep venous thrombosis. In addition, use of antithrombotic prophylaxis was found to decrease the likelihood of these thromboembolic events (P = 0.050; odds ratio = 0.2 for aspirin or subcutaneous heparin, and odds ratio = 0.4 for warfarin or low-molecular-weight heparin). Conclusions In patients undergoing primary elective lower extremity arthroplasty, obesity, poor American Society of Anesthesiologists physical status classification, and lack of thromboprophylaxis are independent risk factors for clinically relevant thromboembolic events.

Background There is limited information about the frequency of perioperative complications after elective primary orthopedic total hip and knee arthroplasty in contemporary practice. The purpose of this study was to determine the frequency of clinically relevant myocardial infarction, pulmonary embolism, deep venous thrombosis, and death within 30 days after elective primary hip or knee arthroplasty treated according to contemporary perioperative management. Methods The authors examined the medical records of consecutive patients undergoing hip or knee arthroplasty at their institution in a 10-yr period. Prospectively collected databases were used to identify patients with the diagnosis of myocardial infarction, pulmonary embolism, deep venous thrombosis, or death using strict validation criteria and diagnostic-certainty categories. Results A total of 10,244 patients underwent primary total hip or knee arthroplasty in the period of study. Of these, 224 patients had one or more adverse events (overall event rate: 2.2%; myocardial infarction: 0.4%; pulmonary embolism: 0.7%; deep venous thrombosis: 1.5%; death: 0.5%). Most adverse events (myocardial infarction, pulmonary embolism, and death) increased in frequency with older age, particularly for patients aged 70 yr or older. Myocardial infarction occurred more frequently in male patients. There were no differences in the overall event frequency between types of procedure. However, pulmonary embolism was highest in patients undergoing bilateral knee operations. Conclusions The overall frequency of serious complications within 30 days after primary total hip or knee arthroplasty with contemporary practice was 2.2%. Accurate knowledge of the perioperative risks associated with widely performed elective operations can be used to implement management strategies that may further improve patient outcomes and decrease cost.