Mycobacterium abscessus: A Rare Cause of Periprosthetic Knee Joint Infection.

A 61-year-old woman with a periprosthetic knee joint infection caused by Mycobacterium abscessus was successfully treated with surgical débridement, multidrug antimicrobial therapy, and staged reimplantation. To the authors' knowledge, this represents the first report of successfully treating this organism after knee arthroplasty. M. abscessus knee infections are rare, and there are no specific guidelines to inform treatment or successful treatment regimens for periprosthetic knee infections. Medical management alone was not successful in this case and hence cannot be recommended. Using a collaborative multidisciplinary approach, including surgical débridement, staged reimplantation, and multidrug antimicrobials, successful eradication of the periprosthetic joint infection caused by M. abscessus was achieved.

Preoperative cerebrospinal fluid ß-Amyloid/Tau ratio and postoperative delirium.

OBJECTIVE: The neuropathogenesis of postoperative delirium remains unknown. Low cerebrospinal fluid (CSF) ßamyloid protein (Aß) and high CSF Tau levels are associated with Alzheimer's disease. We therefore assessed whether lower preoperative CSF Aß/Tau ratio was associated with higher incidence and greater severity of postoperative delirium. METHODS: One hundred and fifty three participants (71±5 years, 53% males) who had total hip/knee replacement under spinal anesthesia were enrolled. CSF was obtained during initiation of spinal anesthesia. The incidence and severity of postoperative delirium were determined by Confusion Assessment Method (CAM) and Memorial Delirium Assessment Scale (MDAS) on postoperative day 1 and 2. Aß40, Aß42, and Tau levels in the CSF were measured by enzyme-linked immunosorbent assay. The relationships among these variables were determined, adjusting for age and gender. RESULTS: Participants in the lowest quartile of preoperative CSF Aß40/Tau and Aß42/Tau ratio had higher incidence (32% versus 17%, P=0. 0482) and greater symptom severity of postoperative delirium (Aß40/Tau ratio: 4 versus 3, P=0. 034; Aß42/Tau ratio: 4 versus 3, P=0. 062, the median of the highest Memorial Delirium Assessment Scale score) as compared to the combination of the rest of the quartiles. The preoperative CSF Aß40/Tau or Aß42/Tau ratio was inversely associated with Memorial Delirium Assessment Scale score (Aß40/Tau ratio: -0.12±0.05, P=0.014, adj. -0.12±0.05, P=0.018; Aß42/Tau ratio: -0.65±0.26, P=0.013, adj. -0.62±0.27, P=0.022). INTERPRETATION: Lower CSF Aß/Tau ratio could be associated with postoperative delirium, pending confirmation of our preliminary results in further studies. These findings suggest potential roles of Aß and/or Tau in postoperative delirium neuropathogenesis.

Novel technique for removal of a broken intracortical screw during THA.

Most reports regarding hardware removal involve the violation of the cortex to allow a specialized to tool to extract a retained fragment. This leaves large, unfilled screw holes that act as stress risers for months postoperatively. This article describes a novel technique to remove a retained intracortical screw fragment during total hip arthroplasty. Conversion of an intertrochanteric osteotomy to a total hip arthroplasty can be made more difficult by anatomical changes to the femur and retained hardware. Direct access to the intramedullary canal during total hip arthroplasty allowed for the safe removal of a retained intracortical screw using this technique.

Surgically induced neuropathic pain: understanding the perioperative process.

Nerve damage takes place during surgery. As a consequence, significant numbers (10%-40%) of patients experience chronic neuropathic pain termed surgically induced neuropathic pain (SNPP). The initiating surgery and nerve damage set off a cascade of events that includes both pain and an inflammatory response, resulting in "peripheral and central sensitization," with the latter resulting from repeated barrages of neural activity from nociceptors. In affected patients, these initial events produce chemical, structural, and functional changes in the peripheral and central nervous systems (CNS). The maladaptive changes in damaged nerves lead to peripheral manifestations of the neuropathic state-allodynia, sensory loss, shooting pains, etc, that can manifest long after the effects of the surgical injury have resolved. The CNS manifestations that occur are termed "centralization of pain" and affect sensory, emotional, and other (eg, cognitive) systems as well as contributing to some of the manifestations of the chronic pain syndrome (eg, depression). Currently there are no objective measures of nociception and pain in the perioperative period. As such, intermittent or continuous pain may take place during and after surgery. New technologies including direct measures of specific brain function of nociception and new insights into preoperative evaluation of patients including genetic predisposition, appear to provide initial opportunities for decreasing the burden of SNPP, until treatments with high efficacy and low adverse effects that either prevent or treat pain are discovered.

The outcome of sequential repeated tibial tubercle osteotomy performed in 2-stage revision arthroplasty for infected total knee arthroplasty.

Thirteen patients with infected total knee arthroplasty treated by 2-stage revision requiring tibial tubercle osteotomy in both stages for extensile exposure were retrospectively analyzed. The preoperative mean range of knee motion improved from 60° (range, 30°-90°) to 94° (range, 70°-120°) at latest follow-up. The Knee Society knee scores and function scores were 39 and 18 preoperatively and 78 and 67 at latest follow-up, respectively. Although proximal migration occurred in 3 cases and a partial proximal avulsion fracture of the osteotomy segment occurred in 1 case after the second-stage reimplantation, radiographic bony union was observed in all cases. Sequential repeated tibial tubercle osteotomy can be a useful extensile surgical approach in staged revision for infected total knee arthroplasty with satisfactory clinical and radiographic outcomes.

Repair of a deficient abductor mechanism with Achilles tendon allograft after total hip replacement.

BACKGROUND: Abductor mechanism insufficiency after total hip arthroplasty is a rare but debilitating problem. The diagnosis is difficult, and when the condition is recognized there are few successful treatment options. The purpose of this study was to review our experience with a surgical technique involving use of a fresh-frozen Achilles tendon allograft with an attached calcaneal bone graft to reconstruct a deficient abductor mechanism after total hip arthroplasty. METHODS: From 2003 to 2006, we performed seven abductor reconstructions with an Achilles tendon allograft in patients with abductor deficiency after total hip arthroplasty. At a mean of twenty-nine months after the total hip arthroplasty, all seven patients had symptoms of lateral hip pain and abductor muscle weakness as demonstrated by a Trendelenburg test. The abductor tendon rupture was diagnosed on the basis of an arthrogram and was confirmed at surgery. RESULTS: Before the reconstruction, the average Harris hip score was 34.7 points and the average pain score was 11.4 points. After a minimum duration of follow-up of twenty-four months, the average Harris hip score was 85.9 points and the average pain score was 38.9 points. CONCLUSIONS: Abductor reconstruction with an Achilles tendon allograft with a calcaneal bone block attached to the greater trochanter can produce substantial relief of pain, increased abductor muscle strength, decreased limp, and improvements in the Trendelenburg sign and in function at the time of early follow-up.

Contemporary cruciate-retaining total knee arthroplasty with a pegged tibial baseplate. Results at a minimum of ten years.

BACKGROUND: A total knee arthroplasty with a four-peg tibial baseplate is an uncommonly used contemporary design. Potential advantages of this baseplate include preservation of host bone, compatibility with minimally invasive techniques, and easier removal with revision techniques. The purpose of this study was to determine the long-term results of a contemporary total knee arthroplasty that included a four-peg tibial baseplate. METHODS: From February 1995 to December 1996, 127 total knee arthroplasties were performed by one surgeon in 115 patients with an average age of seventy years. Clinical and radiographic evaluations were performed with use of the Knee Society scoring system at a minimum of ten years following replacement. Complications were identified by means of chart review and screening for readmission at surrounding institutions. RESULTS: At the time of follow-up, at a minimum of ten years after the arthroplasty, thirty patients (with thirty-three involved knees) were documented to have died and four patients (with seven involved knees) could not be located. The next-of-kin of the patients who had died directly confirmed that the knee was unrevised at the time of death. Eighty-seven knees in eighty-one patients remained available for evaluation after a minimum of ten years of follow-up. Two knees had failed: one had a late infection at three years, and one had aseptic loosening at seven years. The rate of survival free of revision at ten years was 97%. Knee Society knee and function scores averaged 94 and 75 points, respectively. None of the remaining knees had radiographic evidence of loosening. CONCLUSIONS: This study demonstrated excellent, durable clinical and radiographic results at a minimum of ten years after replacement with this cemented, modular, fixed-bearing, cruciate-retaining total knee prosthesis with a four-peg tibial baseplate. We believe that this design is an acceptable option for total knee arthroplasty.

Claw plate fixation of the greater trochanter in revision total hip arthroplasty.

The purpose of this retrospective study was to evaluate a new trochanteric claw plate for trochanteric fixation. From 1998 to 2004, 31 procedures were performed by one surgeon. Mean follow-up was 2.2 years. Indications for the procedure included 16 nonunion, 7 trochanteric osteotomy, 5 periprosthetic fractures, and 3 intraoperative fractures. Median Harris hip scores improved from 47 to 92 points (P < .0001). No patient had an abductor lurch postoperatively (P < .0001). No patient had moderate or severe pain postoperatively (P < .0001). Median active abduction increased from 0 degrees to 25 degrees (P < .0001). Osseous union occurred in 28 of 31 hips. Plate-related complications occurred in 6 of 31 hips. No significant difference was identified for outcomes based on indication. In conclusion, the claw plate in this study can sufficiently treat the complex situation of trochanteric nonunion, fracture, or osteotomy.

Isolated acetabular revision through the posterior approach: short-term results after revision of a recalled acetabular component.

Isolated acetabular revision is commonly associated with high rates of postoperative dislocation. We hypothesize that the dislocation rate in a series of isolated acetabular revisions for loosening of recalled acetabular components is low when strict intraoperative stability testing is coupled with re-repair of the piriformis tendon. Twenty-six isolated revisions of aseptic, loose recalled acetabular components were performed through the posterior approach by a single surgeon. All piriformis tendon and posterior capsular repairs from the index operation were considered intact at the time of revision. The piriformis tendon was re-repaired in each revision case. The average revision acetabular component was 3 mm larger than the index component. In this select group of isolated acetabular revisions, strict intraoperative stability testing and re-repair of the piriformis tendon yielded zero dislocations.

Osteolysis of the pelvis: evaluation and treatment.

Osteolysis of the pelvis is a common and well-recognized complication associated with total hip arthroplasty. The diagnosis and treatment of osteolysis of the pelvis is a challenging and controversial problem. Osteolysis of the pelvis often is asymptomatic and does not present with symptoms until considerable bone loss and loosening of the acetabular socket occur. Radiographs are the most common way to detect and monitor osteolysis around an implant. However, lesions viewed radiographically usually are underestimations of the lesions found intraoperatively. Moreover, some advocate computed tomography scanning to evaluate these lesions. The indications for treatment of osteolysis with cemented acetabular components are defined more clearly than with a cementless component. If the cemented or cementless acetabular component is loose, then revision is necessary. However, it is less clear when to intervene surgically with a well-fixed cup with osteolysis. Many early reports advocated the removal of a well-fixed socket during revision surgery for osteolysis and polyethylene wear. However, the removal of a well-fixed socket has the potential for significant damage and loss of the surrounding bone resulting in loss of integrity of a column or pelvic discontinuity, which may compromise placing another acetabular component. Recently, a new treatment strategy of retaining a well-fixed socket, exchanging the liner, and grafting lesions has proven successful. Without the removal of the acetabular shell, different techniques are needed to graft the osteolytic lesions. Osteolysis is a difficult problem; however, with radiographic surveillance to monitor patients for lesions, proper indications, and good surgical techniques, the treatment of osteolysis of the pelvis can result in a well-functioning total hip arthroplasty.