Faculty Bibliography

Modular polyethylene failure and attendant revision play an increasing role in hip arthroplasty. In spite of well-fixed, well-aligned components, bearing exchange has a high risk of chronic instability, which may be attributed to the resection of stabilizing soft tissue structures to gain exposure. This creates a difficult situation for the surgeon and an inexplicable one for the patient with a previously well-functioning implant. The senior author modified a technique previously described by Shaw that included an osteotomy of the posterior one third of the greater trochanter and preservation of posterior soft tissues. Thirty-five patients underwent 47 revision procedures utilizing this approach, including 16 modular component and 31 more extensive procedures. There were no dislocations or significant complications and no loss of reduction or nonunion. The approach offers excellent exposure while preserving stabilizing soft tissues

Recurrent hemarthrosis following a revision total knee arthroplasty is a rare complication. The likelihood of encountering bleeding complications in patients with hemophilia C following major surgery is unpredictable. Although the use of postoperative chemotherapeutic agents to prevent deep venous thrombosis (DVT) is considered the standard of care for most patients, its use in the hemophiliac population is unknown. This case describes a woman with Hemophilia C who presented with recurrent hemarthrosis 9 days after her revision total knee arthroplasty. Initial treatment efforts were directed towards treating the patient's underlying coagulopathy. Repeated transfusions of fresh frozen plasma and desmopressin were given in an attempt to achieve hemostasis. However the hemarthrosis did not resolve and 36 days postoperatively, a pseudoaneurysm of the left superior geniculate artery was found by angiography and percutaneously embolized. This article presents the first case, to our knowledge, of recurrent hemarthrosis in a hemophiliac patient after revision total knee arthroplasty. It further highlights the importance of considering all possible causes of postoperative bleeding to make a timely diagnosis in the face of a confounding clinical picture

There has been an increasing demand for hip resurfacing as an alternative to total hip arthroplasty. A number of reports have been published recently detailing the technique and role of resurfacing in a variety of extra-articular deformities, dysplastic conditions, and settings of retained intramedullary hardware and other impediments. The following report proposes a classification system that recognizes intramedullary and extramedullary deformities. With the long-term expectation for resurfacing, these complex situations may require categorization to segregate risk factors in order to allow for better planning and prognostication

BACKGROUND: The stability of total hip replacements has been directly related to the diameter of the femoral head in several studies; however, durability has necessitated the use of femoral heads with a relatively small diameter. Recent developments in metal-on-metal technology have allowed for the use of femoral head bearings that are anatomic in diameter. In this case series, we report on the early results of patients who were at greater risk for dislocation because of anatomic deficiencies or increased range-of-motion activities and underwent hip arthroplasty with implants that had articulating surfaces approaching anatomic dimensions. METHODS: Thirty-four patients underwent forty total hip arthroplasties with use of a modular metal-on-metal articulation with an anatomic diameter femoral head and a press-fit stem. Thirty patients were active, and four patients were profoundly disabled and had bone or soft-tissue deficiencies that would increase the risk for dislocation. Dislocation precautions were maintained for six weeks, and patients were allowed extreme ranges of motion at three months. RESULTS: There were no dislocations. Active patients continued in extreme range-of-motion activities. Disabled patients improved but were limited by their comorbidities. CONCLUSIONS: Anatomic diameter femoral heads offer distinct theoretical advantages in total hip arthroplasty. These short-term results are encouraging, and further study of this new technology in a larger series with a longer follow-up period is warranted

OBJECTIVE: To determine whether protein prenylation (farnesyl/geranylgeranylation) regulates matrix metalloproteinase (MMP) secretion from rheumatoid arthritis (RA) synovial fibroblasts (RASFs), and whether MMP-1 secretion can be regulated by statins or prenyltransferase inhibitors via effects mediated by ERK, JNK, and NF-kappaB. METHODS: RASFs obtained from patients during elective knee replacement surgery were assessed by immunoblotting and/or enzyme-linked immunosorbent assay for secretion of MMP-1 and MMP-13 in the presence of tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), statins, the farnesyl transferase (FT) inhibitor FTI-276 and geranylgeranyl transferase inhibitor GGTI-298, and prenyl substrates (farnesyl pyrophosphate [FPP] and geranylgeranyl pyrophosphate [GGPP]). Activities of JNK and ERK were determined by phosphoimmunoblotting, and NF-kappaB activation was determined by nuclear translocation of the p65 component. RESULTS: FTI-276, but not statins, inhibited RASF secretion of MMP-1, but not MMP-13, following induction with TNFalpha (P = 0.0007) or IL-1beta (P = 0.006). Loading RASFs with FPP to promote farnesylation enhanced MMP-1 secretion. FTI-276 inhibited activation of JNK (P < 0.05) and NF-kappaB (P = 0.02), but not ERK. In contrast, GGTI-298 enhanced, while GGPP inhibited, MMP-1 secretion. FTI-276 and GGTI-298 together had no effect on MMP-1 secretion. Stimulation of RASFs with TNFalpha or IL-1beta led to increased expression and activity of FT. CONCLUSION: Protein farnesylation is required for expression and secretion of MMP-1 from RASFs, via effects on JNK and NF-kappaB. The ability of cytokines to stimulate the expression and activity of FT suggests that FT may be increased in the rheumatoid joint. In contrast, geranylgeranylation down-regulates MMP-1 expression. Statins simultaneously inhibit farnesylation and geranylgeranylation, and in consequence do not inhibit MMP-1 secretion. The ability of FTI-276 to inhibit MMP-1 secretion suggests a potential therapeutic strategy in RA

Periprosthetic femoral fractures associated with well-fixed total hip or total knee prostheses present a challenging management problem as these injuries typically occur in osteoporotic bone. Conventional management entails extensive periosteal stripping to allow for plate fixation. We reviewed a consecutive series of patients who sustained fractures associated with a well fixed total knee prosthesis, a total hip prosthesis, or both. Twenty four patients with a mean age of 69.4 years were included. All patients underwent fixation via percutaneous insertion techniques with a first generation locking plate and screws (LISS-Less Invasive Skeletal Stabilization, Synthes, Paoli, PA). Three patients sustained fractures distal to a well-fixed total hip prosthesis, eighteen fractures occurred above a well-fixed total knee femoral component, and three were interprosthetic. The mean length of time from the index procedure to fracture was 76 months, range (2-172 months). Blood loss was minimal in each case, with a mean operative time of 90min (range 60-120min). Twenty one of twenty four went on to unite at a mean 6.2 months (range 3-19 months). Three patients underwent further surgery. One failure of fixation was encountered. Percutaneous fixation is technically demanding as it requires stable fixation without direct visualisation of the fracture site or the entire fixation device. Our results suggest percutaneous fixation with the LISS plate is an effective although technically demanding method of treatment. Complication rates were comparable to existing reports of this treatment method, and appear to be improved over traditional methods of fixation

PURPOSE: To retrospectively assess magnetic resonance (MR) imaging features of radial tunnel syndrome. MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was waived for the retrospective HIPAA-compliant study. MR images of 10 asymptomatic volunteers (six men, four women; mean age, 30 years) and 25 patients (11 men, 14 women; mean age, 49 years) clinically suspected of having radial tunnel syndrome were reviewed for morphologic and signal intensity alterations of the posterior interosseous nerve and adjacent soft-tissue structures. MR images of the asymptomatic volunteers were reviewed to establish the normal appearance of the radial tunnel. MR images of the symptomatic patients were evaluated for the following: signal intensity alteration and morphologic alteration of the posterior interosseous nerve; the presence of mass effect on the posterior interosseous nerve such as the presence of bursae, a thickened leading edge of the extensor carpi radialis brevis, or prominent radial recurrent vessels; signal intensity alteration within the depicted forearm musculature such as edema or atrophy; and signal intensity changes at the origin of the common extensor and common flexor tendons, which would suggest a diagnosis of epicondylitis. RESULTS: All images of volunteers demonstrated normal morphology and signal intensity within the posterior interosseous nerve and adjacent soft tissues. Two volunteers had borderline thickening of the leading edge of the extensor carpi radialis brevis. Thirteen patients (52%) had denervation edema or atrophy within muscles (supinator and extensors) innervated by the posterior interosseous nerve. One patient had isolated pronator teres edema. Seven (28%) patients had the following mass effects along the posterior interosseous nerve: thickened leading edge of the extensor carpi radialis brevis (n = 4), prominent radial recurrent vessels (n = 1), schwannoma (n = 1), or bicipitoradial bursa (n = 1). The rest of the patients had either normal MR imaging findings (n = 4) or lateral epicondylitis (n = 2). CONCLUSION: Muscle denervation edema or atrophy along the distribution of the posterior interosseous nerve is the most common MR finding in radial tunnel syndrome

Despite major advances in the field of total joint arthroplasty, a standardized postoperative management protocol currently does not exist following total hip arthroplasty (THA) and total knee arthroplasty (TKA). A survey was mailed to the active members of the American Association of Hip and Knee Surgeons to investigate issues such as postoperative rehabilitation and activity restriction. The information derived from this survey provides the total joint surgeon with a compilation and consensus of responses that can serve as the foundation for a standardized postoperative protocol for THA and TKA surgery

We evaluated the use of a pure press-fit technique in 220 porous-coated acetabular components without screw holes at mean follow-up of 6.1 years (4-7.5 years). The socket had a 14 degrees enhanced gradient at the periphery and was underreamed by 1 to 2 mm depending on bone quality. The Harris Hip average score was 44.3 (26-70) preoperatively and 93.1 (66-100) at final follow-up. There were no postoperative gaps in any zone. Nonprogressive radiolucent lines were detected in 4 hips. There was no movement or migration of the acetabular component on the follow-up x-rays. Pelvic osteolysis was not observed. Whereas 5 cups (2.3%) had revisions, none was revised for aseptic loosening. The press-fit technique provides stability in appropriate cases avoiding the theoretical complications related to screws or screw holes.