Uniformly low serum cobalt levels after modular dual-mobility total hip arthroplasties with ceramic heads: a prospective study in high-risk patients.

AIMS: Modular dual-mobility constructs reduce the risk of dislocation after revision total hip arthroplasty (THA). However, questions about metal ions from the cobalt-chromium (CoCr) liner persist, and are particularly germane to patients being revised for adverse local tissue reactions (ALTR) to metal. We determined the early- to mid-term serum Co and Cr levels after modular dual-mobility components were used in revision and complex primary THAs, and specifically included patients revised for ALTR. PATIENTS AND METHODS: Serum Co and Cr levels were measured prospectively in 24 patients with a modular dual-mobility construct and a ceramic femoral head. Patients with CoCr heads or contralateral THAs with CoCr heads were excluded. The mean age was 63 years (35 to 83), with 13 patients (54%) being female. The mean follow-up was four years (2 to 7). Indications for modular dual-mobility were prosthetic joint infection treated with two-stage exchange and subsequent reimplantation (n = 8), ALTR revision (n = 7), complex primary THA (n = 7), recurrent instability (n = 1), and periprosthetic femoral fracture (n = 1). The mean preoperative Co and Cr in patients revised for an ALTR were 29.7 µg/l (2 to 146) and 21.5 µg/l (1 to 113), respectively. RESULTS: Mean Co and Cr levels were 0.30 µg/l and 0.76 µg/l, respectively, at the most recent follow-up. No patient had a Co level ≥ 1 µg/l. Only one patient had a Cr level ≥ 1 µg/l. That patient's Cr level was 12 µg/l at 57 months after revision THA for ALTR (and decreased ten-fold from a preoperative Cr of 113 µg/l). CONCLUSION: At a mean of four years, no patient with a modular dual-mobility construct and ceramic femoral head had elevated Co levels, including seven patients revised specifically for ALTR. While further studies are required, we support the selective use of a modular dual-mobility construct in revision and complex primary THAs for patients at high risk for instability. Cite this article: Bone Joint J 2019;101-B(6 Supple B):57-61.

A randomized controlled trial of fixed- versus mobile-bearing total knee arthroplasty: a follow-up at a mean of ten years.

Aims: It has been suggested that mobile-bearing total knee arthroplasty (TKA) might lead to better outcomes by accommodating some femorotibial rotational mismatch, thereby reducing contact stresses and polyethylene wear. The aim of this study was to determine whether there is a difference between fixed- and mobile-bearing versions of a contemporary TKA with respect to durability, range of movement (ROM) and function, ten years postoperatively. Patients and Methods: A total of 240 patients who were enrolled in this randomized controlled trial (RCT) underwent a primary cemented TKA with one of three tibial components (all-polyethylene fixed-bearing, modular metal-backed fixed-bearing and mobile-bearing). Patients were reviewed at a median follow-up of ten years (IQR 9.2 to 10.4). Results: There was no difference in durability, as measured by survivorship free of revision for any reason, nor in mean maximal ROM at ten years (p = 0.8). There was also no difference in function, as measured by Knee Society (KS) function scores (p = 0.63) or the prevalence of patellar tilt (p = 0.12). Conclusion: In this clinical RCT, the mobile-bearing design of TKA was found to be reliable and durable, but did not provide better maximum knee flexion, function or durability ten years postoperatively compared with a posterior-stabilized, fixed-bearing design incorporating either an all-polyethylene or a modular-metal-backed tibial component. Cite this article: Bone Joint J 2018;100-B:925-9.

A single-centre study of haemostatic outcomes of joint replacement in von Willebrand disease and control patients and an analysis of the literature.

INTRODUCTION: Haemostatic assessments of patients with von Willebrand disease (VWD) who undergo total knee arthroplasty (TKA) and total hip arthroplasty (THA) have mainly relied on subjective parameters. AIMS: To compare objective haemostatic outcomes of TKA/THA in VWD patients and controls without bleeding disorders. METHODS: We retrospectively analysed haemostatic outcomes in VWD patients undergoing TKA/THA from 1993 to 2011 and compared them with two matched controls per operation. Using one-way analysis of variance, we tested the effect of VWD on bleeding risk after TKA and THA. RESULTS: Twelve VWD patients (6 type 1, 3 type 2M, 1 each of types 2A/2B/3) undergoing 19 operations (12 TKA, 7 THA) were matched to 38 controls. One (5%) of 19 operations in VWD patients and none of the control operations met clinical criteria for major bleeding. Baseline and postoperative day 1 haemoglobin levels, postoperative blood loss, transfused red blood cells (RBCs) and mean hospitalization days were not significantly different. More VWD patients than controls received RBC transfusions [12 (63%) vs. 12 (32%)]. Only 9 (47%) VWD patients vs. 38 (100%) controls received pharmacologic VTE prophylaxis. No postoperative symptomatic VTE occurred in either group. CONCLUSION: In this largest, single-institutional study, von Willebrand factor replacement based on daily levels resulted in low frequency of major bleeding in VWD patients after TKA/THA. RBC transfusion was more frequent compared with matched controls, but other objective measures of haemostasis were similar. Lack of sufficient details in published reports precluded comparison of haemostatic outcomes.

Revision total hip arthroplasty after removal of a fractured well-fixed extensively porous-coated femoral component using a trephine.

When fracture of an extensively porous-coated femoral component occurs, its removal at revision total hip arthroplasty (THA) may require a femoral osteotomy and the use of a trephine. The remaining cortical bone after using the trephine may develop thermally induced necrosis. A retrospective review identified 11 fractured, well-fixed, uncemented, extensively porous-coated femoral components requiring removal using a trephine with a minimum of two years of follow-up. The mean time to failure was 4.6 years (1.7 to 9.1, standard deviation (sd) 2.3). These were revised using a larger extensively porous coated component, fluted tapered modular component, a proximally coated modular component, or a proximal femoral replacement. The mean clinical follow-up after revision THA was 4.9 years (2 to 22, sd 3.1). The mean diameter of the femoral component increased from 12.7 mm (sd 1.9) to 16.2 mm (sd 3.4; p > 0.001). Two revision components had radiographic evidence of subsidence that remained radiographically stable at final follow-up. The most common post-operative complication was instability affecting six patients (54.5%) on at least one occasion. A total of four patients (36.4%) required further revision: three for instability and one for fracture of the revision component. There was no statistically significant difference in the mean Harris hip score before implant fracture (82.4; sd 18.3) and after trephine removal and revision THA (81.2; sd 14.8, p = 0.918). These findings suggest that removal of a fractured, well-fixed, uncemented, extensively porous-coated femoral component using a trephine does not compromise subsequent fixation at revision THA and the patient's pre-operative level of function can be restored. However, the loss of proximal bone stock before revision may be associated with a high rate of dislocation post-operatively.

Revision total hip arthroplasty in patients with extensive proximal femoral bone loss using a fluted tapered modular femoral component.

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.

Obesity is a major risk factor for the development of complications after peri-acetabular osteotomy.

Obesity is a risk factor for complications following many orthopaedic procedures. The purpose of this study was to investigate whether obesity was an independent risk factor increasing the rate of complications following periacetabular osteotomy (PAO) and to determine whether radiographic correction after PAO was affected by obesity. We retrospectively collected demographic, clinical and radiographic data on 280 patients (231 women; 82.5% and 49 men; 17.5%) who were followed for a mean of 48 months (12 to 60) after PAO. A total of 65 patients (23.2%) were obese (body mass index (BMI) > 30 kg/m(2)). Univariate and multivariate analysis demonstrated that BMI was an independent risk factor associated with the severity of the complications. The average probability of a patient developing a major complication was 22% (95% confidence interval (CI) 11.78 to 38.21) for an obese patient compared with 3% (95% CI 1.39 to 6.58) for a non-obese patient The odds of a patient developing a major complication were 11 times higher (95% CI 4.71 to 17.60, p < 0.0001) for an obese compared with a non-obese patient. Following PAO surgery, there was no difference in radiographic correction between obese and non-obese patients. PAO procedures in obese patients correct the deformity effectively but are associated with an increased rate of complications.

Total hip replacement in patients with Down syndrome and degenerative osteoarthritis of the hip.

Dysplasia of the hip, hypotonia, osteopenia, ligamentous laxity, and mental retardation increase the complexity of performing and managing patients with Down syndrome who require total hip replacement (THR). We identified 14 patients (six males, eight females, 21 hips) with Down syndrome and degenerative disease of the hip who underwent THR, with a minimum follow-up of two years from 1969 to 2009. In seven patients, bilateral THRs were performed while the rest had unilateral THRs. The mean clinical follow-up was 5.8 years (standard deviation (sd) 4.7; 2 to 17). The mean Harris hip score was 37.9 points (sd 7.8) pre-operatively and increased to 89.2 (sd 12.3) at final follow-up (p = 1x10(-9)). No patient suffered a post-operative dislocation. In three patients, four hips had revision THR for aseptic loosening at a mean follow-up of 7.7 years (sd 6.3; 3 to 17). This rate of revision THR was higher than expected. Our patients with Down syndrome benefitted clinically from THR at mid-term follow-up.

Hip dysplasia in the young adult: an osteotomy solution.

The treatment of hip dysplasia should be customised for patients individually based on radiographic findings, patient age, and the patient's overall articular cartilage status. In many patients, restoration of hip anatomy as close to normal as possible with a PAO is the treatment of choice.

Retrieval analysis of squeaking ceramic implants: are there related specific features?

INTRODUCTION: Ceramic-on-ceramic total hip arthroplasty is routinely used for young and active patients with end stage of hip osteoarthritis. However, squeaking noise is a recently identified problem with such bearing surface. Many in vivo and in vitro studies have been conducted trying to find the potential causes of this phenomenon. However, we are not aware of any study analyzing retrieved ceramic implants for squeaking. HYPOTHESIS: Our primary hypothesis was that the surface analysis of retrieved ceramic implants with squeaking would present interesting deteriorations that could explain the squeaking noise. MATERIALS AND METHODS: Nine retrieved squeaking implants from ceramic-on-ceramic total hip arthroplasty that were retrieved for various reasons (two exclusively for squeaking, four for recurrent dislocation, one for aseptic loosening and two for instability) were analyzed. Implant positioning was calculated, macroscopic damages were noticed and microscopic roughness was analyzed. The retrieved implants were then tested on a hip simulator reproducing flexion/extension motions in several situations in lubricated and non-lubricated conditions in order to reproduce squeaking. RESULTS: Five cups were considered with borderline insufficient anteversion. Gross impingement damage was visible on seven implants. All the retrieved heads had visible metal transfer on their surface. Eight implants had visible stripe wear. Microscopic analysis showed roughness higher than six microns on the retrieved heads. Squeaking was reproduced in vitro in dry conditions. In lubricated conditions, squeaking did not occur for the retrieved hips. DISCUSSION: This retrieval analysis suggests that problems of cup orientation and design which can lead to impingement can generate lubrication problems because of metal transfer plus/minus stripe wear which is a common theme in ceramic-on-ceramic bearings that squeak.

Caution Should be Taken in Performing Surgical Hip Dislocation for the Treatment of Femoroacetabular Impingement in Patients Over the Age of 40.

BACKGROUND: Open and arthroscopic procedures are treatment options for patients with femoroacetabular impingement (FAI). Age has been found to be a predictive factor in the outcome of patients undergoing periacetabular osteotomy (PAO) for hip dysplasia. It is unclear if older age contraindicates joint preservation through a surgical hip dislocation (SHD). QUESTIONS/PURPOSE: The purpose of this retrospective case series was to evaluate the short-term outcomes of patients over 40 years of age without radiographic evidence of end-stage arthritis who underwent SHD for the treatment of FAI and to determine whether older age should be a contraindication for joint-preserving procedures in these patients. Our specific aims included (1) documenting the intraoperative findings and procedures, (2) assessing pain relief provided, and (3) assessing treatment failures and postoperative complications, noting the number of patients that ultimately required total hip arthroplasty (THA). PATIENTS AND METHODS: All patients at age 40 and older who had SHD for the treatment of FAI were identified from a series of patients treated with SHD. Clinical notes, radiographs, and operative reports were reviewed to determine clinical results, complications, and the need for additional procedures. The minimum follow-up was 1 year (mean 3.9 years; range 1-8 years). RESULTS: At final follow-up, 11/22 (50%) of hips had pain relief, while 11/22 (50%) either continued having significant symptoms or required THA. Five (23%) reported nontrochanteric pain symptoms that were the same or worse than before surgery, and six hips (27%) underwent subsequent THA). The average time between SHD and THA was 1.9 years (0.9-6.2). The average age of patients who went on to require THA was 45 (42-50) years. CONCLUSIONS: Surgical hip dislocation can be used for the treatment of FAI in patients over age 40, but strict selection criteria should be adhered to, as only half of the patients experienced significant improvement in their hip pain. THA was required in one-third of hips for continued pain and radiographic progression of arthritis. SHD for treatment of pathology that is not amenable to hip arthroscopy should remain a surgical option in older patients with FAI only if joint degeneration is not present.

Developmental dysplasia of the hip: is acetabular retroversion a crucial factor?

OBJECTIVE: The objective of this study was to investigate a possible relation between congenital hip dysplasia and acetabular retroversion and to explore the eventual influence of the latter in the surgical decision for periacetabular osteotomy. MATERIALS AND METHODS: We assessed the classical morphological characteristics of both hips, with an additional newly described retroversion index. The study was conducted in 174 patients with uni- or bilateral congenital hip dysplasia having undergone unilateral (153 patients) or bilateral (21 patients) periacetabular osteotomy when respectively one or both dysplastic hips remained symptomatic. RESULTS: In the group of operated hips (195 hips in total), 53% of the acetabuli were anteverted, 42% retroverted, and 5% neutral orientations. The group of nonoperated hips (153 hips) included 24% normal hips, 22% hips with normal coverage but retroverted, 35% dysplastic hips with anteverted or neutral orientation, and 19% dysplastic retroverted hips. Comparing the two hips in the subgroup of patients in whom the operated and nonoperated sides were both dysplastic failed to demonstrate statistically significant difference in the mean retroversion index. However, all the other variables measured were significantly different; with the operated side more dysplastic. Comparing the two hips in the other subgroups showed that acetabular retroversion was nearly always bilateral and symmetrical, even in presence of unilateral congenital dysplasia. DISCUSSION: Our data suggest that the presence of acetabular retroversion is probably independent of the congenital hip dysplasia and that this abnormality seems at best a secondary factor in the appearance of dysplastic hip symptoms. LEVEL OF EVIDENCE: Level IV, retrospective diagnostic study.

Pregnancy and childbirth after total hip arthroplasty.

We surveyed 343 young women with 420 total hip arthroplasties (THAs) regarding pregnancy and childbirth after THA. The mean age at surgery was 35 years (18 to 45). The mean length of follow-up after the initial arthroplasty was 16 years (6 to 27). Of these 343 women, 47 (13.7%) had a successful pregnancy after their primary THA. The first baby after a THA was delivered vaginally in 30 patients and by Caesarean section in 17. Of the 343 patients, 138 underwent a revision. For the entire series, the risk of revision at five years was 5%, at ten years 24%, and at 20 years 50%. After adjusting for age at surgical intervention, the risk of revision was not significantly associated with childbirth. Of the 47 patients who had a successful pregnancy, 28 (60%) noted an increase in pain in the hip during pregnancy and ten of these patients had persistent pain after their pregnancy. Seven patients complained of pain in the groin in the replaced hip after childbirth. At the time of this survey, five of these patients (70%) had had revision THA. Childbirth is not affected by the presence of a THA. Pregnancy after THA is not associated with decreased survival of the prosthesis. Pain in the hip is common during pregnancy in these patients. Pain in the groin which persists after delivery commonly leads to revision of the THA.

Long-acting follicle-stimulating hormone analogs containing N-linked glycosylation exhibited increased bioactivity compared with o-linked analogs in female rats.

The effects of altering the number and type of additional carbohydrate moieties on the pharmacokinetic and pharmacodynamic properties of FSH were examined in this report. A series of single-chain follitropins, containing variable numbers of additional N- (or O-) linked carbohydrates, were designed and expressed in Chinese hamster ovary cells. Proper folding, efficient receptor binding, and signal transduction were confirmed by in vitro assays. Pharmacokinetic and pharmacodynamic parameters were evaluated in immature female Sprague Dawley rats. Increasing the number of glycosylation sites with either N- (or O-) linked moieties extended the elimination half-life as much as 2-fold compared with recombinant human FSH (rhFSH). However, there was a maximum elimination half-life such that further glycosylation provided no additional lengthening of the half-life. Conversely, biopotency, as assessed by inhibin A levels 74 h post injection, and follicle production were significantly higher for the N-linked analogs. Rats stimulated with the longest acting analogs (either N- or O-linked) showed significantly higher ovarian weights than rats receiving a single injection of rhFSH. The analog containing four additional N-linked sites (rhFSH-N4) had the greatest number of large, preovulatory follicles. Although the half-life of rhFSH-N4 displayed no further enhancement beyond the other longest acting analogs, this analog exhibited significantly increased biopotency in rats. This work provides the basis for the generation of a series of reagents potentially useful for therapeutic applications.

The decision to accept treatment for osteoporosis following hip fracture: exploring the woman's perspective using a stage-of-change model.

Despite the availability of medications that reduce fracture risk, most women who sustain a hip fracture are not evaluated or treated for osteoporosis. While a number of studies have attributed this to a lack of physician awareness, no studies have evaluated this problem from the patient's perspective. To explore the process a woman negotiates when deciding to accept pharmacologic treatment for osteoporosis after hip fracture, we used a stage-of-change model to characterize a consecutive series of 70 postmenopausal women (mean age 85 years) admitted to a tertiary care hospital with an acute low-impact hip fracture between May 2000 and August 2000. We measured stage-of-change using a modified form of the Weinstein Precaution Adoption Process Model (PAPM). The majority of patients (65%) were ineligible because of dementia or delirium; only 29 were eligible and 21 were enrolled. Most women (62%) were in stages 1 or 2 of the PAPM, indicating that they were unaware of osteoporosis or had never considered pharmacologic treatment for it. The only factors associated with a more advanced PAPM stage (indicating active consideration or currently taking treatment) were a previous bone mineral density (BMD) evaluation ( p = 0.007) and a diagnosis of osteoporosis ( p = 0.001). Although 48% of women had a previous fragility fracture and osteoporosis knowledge was poor overall (mean score 52% correct), neither was associated with a more advanced PAPM stage in this sample. In conclusion, women evaluated after hip fracture were not ready to accept pharmacologic treatment for osteoporosis; they were unaware that they had osteoporosis or had never considered treatment for it. For a woman to advance through the behavior change process, she must first be made aware of the problem that requires a change in behavior. Physicians play a crucial role in promoting awareness of the diagnosis of osteoporosis after fracture, which in turn is associated with patient advancement through the behavior change process and the decision to accept pharmacologic intervention. The large number of cognitively impaired patients in this population, however, will certainly make efforts to improve osteoporosis awareness, diagnosis and intervention more challenging.

A large lumbar hernia presenting as a flank mass after total hip arthroplasty.

Soft tissue swelling occasionally can be seen about the incision after a total hip arthroplasty. We report a case of a lateral wall hernia occurring immediately after a total hip arthroplasty that presented as a mass over the proximal aspect of the hip incision.

Uncemented acetabular components with bulk femoral head autograft for acetabular reconstruction in developmental dysplasia of the hip: results at five to twelve years.

BACKGROUND: Anterolateral acetabular bone deficiency is one of the technical problems associated with total hip arthroplasty in patients with developmental hip dysplasia. The purpose of this study was to evaluate the results of one method of acetabular reconstruction for hip dysplasia-placement of an uncemented socket in conjunction with a bulk femoral head autograft. METHODS: Forty-four hips in thirty-five patients (twenty-nine female and six male; average age, thirty-nine years) with developmental hip dysplasia were treated with primary total hip arthroplasty with use of an uncemented porous-coated titanium cup fixed with screws and an autogenous bulk femoral head graft. The patients were followed clinically in a prospective fashion for five to 12.3 years (mean, 7.5 years), and radiographs were analyzed retrospectively. RESULTS: Four acetabular components were revised: two, because of severe polyethylene wear and osteolysis; one, because of aseptic loosening; and one, because of fracture of the acetabular shell. The mean Harris hip score for the unrevised hips improved from 51 points preoperatively to 91 points postoperatively. No unrevised socket had definite radiographic evidence of loosening. Forty-three of the forty-four hips had no radiographic evidence of resorption of the graft or had radiographic evidence of resorption limited to the nonstressed area of the graft lateral to the edge of the cup. CONCLUSIONS: This method of reconstruction provided reliable acetabular fixation and appeared to restore acetabular bone stock in patients with developmental hip dysplasia. We use this technique for patients with moderate anterolateral acetabular bone deficiency requiring total hip arthroplasty.

Poor outcomes of isolated tibial insert exchange and arthrolysis for the management of stiffness following total knee arthroplasty.

BACKGROUND: Severe stiffness after total knee arthroplasty is a debilitating problem. In patients with securely fixed and appropriately aligned components, arthrolysis of adhesions and exchange to a thinner tibial polyethylene insert may appear to be a reasonable and logical solution. We reviewed our experience with this procedure to determine its efficacy. METHODS: From 1992 through 1998, seven knees with marked stiffness after total knee arthroplasty were treated at our institution with arthrolysis of adhesions and conversion to a thinner tibial polyethylene insert. Only patients in whom the total knee prosthesis was well aligned, well fixed, and not associated with infection were included. There were five women and two men with a mean age at revision of sixty-one years (range, thirty-eight to seventy-four years). The average time to revision was twelve months, and the mean arc of motion prior to revision was 38.6 degrees (range, 15 degrees to 60 degrees ). The duration of follow-up after the insert exchange averaged 4.2 years (range, two to eight years). RESULTS: Mean Knee Society pain and function scores changed from 44 and 36.4 points preoperatively to 39.6 and 46 points at the time of final follow-up. Two knees were rerevised, one because of infection and the other because of aseptic loosening of the components. The five remaining knees were painful and stiff at the time of final follow-up. Four of these five knees were severely painful, and one knee was moderately and occasionally painful. The mean arc of motion of these five knees was 58 degrees (range, 40 degrees to 70 degrees ) at the time of final follow-up. CONCLUSION: Isolated tibial insert exchange, arthrolysis, and débridement failed to provide a viable solution to the difficult and poorly understood problem of knee stiffness in a group of carefully selected patients following total knee arthroplasty. We therefore have little enthusiasm for the continued use of this strategy.

Total knee arthroplasty in patients with ankylosing spondylitis.

BACKGROUND: Ankylosing spondylitis is a seronegative spondyloarthropathy that primarily affects the sacroiliac joints, spine, hips, and, less commonly, the knee joints. The purpose of this study was to evaluate the results in a consecutive group of patients with ankylosing spondylitis who underwent total knee arthroplasty. METHODS: The results of thirty total knee arthroplasties in twenty patients with ankylosing spondylitis were reviewed. There were seventeen men and three women, with an average age of fifty-five years (range, twenty-eight to sixty-seven years) at the time of the arthroplasty. The diagnosis of ankylosing spondylitis was established preoperatively with use of the New York criteria. All patients received a cemented condylar-type implant. The average duration of follow-up was 11.2 years (range, three to sixteen years). RESULTS: The average Knee Society pain score improved from 14 points preoperatively to 76.3 points at the time of the latest follow-up. The improvement in the average Knee Society function score was less impressive, with an increase from 16.3 points preoperatively to 58.7 points at the time of the latest follow-up. The average arc of motion was 84.8 degrees prior to the arthroplasty and 86.7 degrees at the time of the final follow-up. Six knees (20%) had heterotopic bone formation. Three knees required manipulation under anesthesia because of poor motion postoperatively. There was one revision, due to loosening of a patellar component. All other components were radiographically stable at the time of the latest follow-up. CONCLUSIONS: Total knee arthroplasty with cement in patients with ankylosing spondylitis provided excellent pain relief and durable fixation at an average of 11.2 years postoperatively. However, patients with ankylosing spondylitis are at increased risk for the development of stiffness and heterotopic bone formation.

Thirty-day mortality after total knee arthroplasty.

BACKGROUND: There have been sporadic reports on perioperative mortality associated with total knee arthroplasty. The purpose of this study was to determine risk factors for such mortality. METHODS: A computer-assisted review of the records of 22,540 consecutive patients who had undergone total knee arthroplasty between 1969 and 1997 was performed to identify all patients who had died within thirty days after the procedure. A detailed analysis of the medical, surgical, anesthetic, and pathological records of the patients was performed, and the mortality was determined according to age, gender, diagnosis, and fixation method. RESULTS: The rate of mortality within thirty days after the operation was 0.21% (forty-seven of 22,540). All deaths occurred in the group of 18,810 patients who had received a cemented implant, and no deaths occurred among the 3730 patients who had received an uncemented implant (p < 0.0001). The mortality rate was 0.24% (forty-three of 18,165) after primary arthroplasty and 0.09% (four of 4375) after revision arthroplasty (p < 0.0003). Three patients (0.01%) died during the operation. Forty-three of the forty-seven patients who died had a history of preexisting cardiovascular and/or pulmonary disease. Simultaneous bilateral total knee arthroplasty was associated with a significantly higher rate of perioperative mortality (p < 0.002). CONCLUSIONS: Factors that were associated with a significantly increased mortality after total knee arthroplasty included an age of more than seventy years, primary (as compared with revision) knee surgery, use of a cemented prosthesis, preexisting cardiopulmonary disease, and simultaneous bilateral arthroplasty.