Medication-related osteonecrosis of the jaw: A disease of significant importance for older patients.

BACKGROUND: Medication-related osteonecrosis of the jaw (MRONJ) is clinically defined as a non-healing jawbone ulcerative-necrotic lesion appearing after dental therapy or minor trauma in patients treated previously with anti-resorptive, anti-angiogenic or immunomodulators. Older patients with osteoporosis and cancer receive these pharmacological agents regularly. As these patients are long-term survivors, efficient treatment is of paramount importance for their quality of life. METHODS: Literature searches via PubMed were conducted to identify relevant MRONJ studies. Basic information on MRONJ classification, clinical features, and pathosphysiology is presented herein as well as various clinical studies dealing with MRONJ in patients with osteoporosis and cancer. Lastly, we discuss current managment of patients and new trends in treatment of MRONJ. RESULTS: Although close follow-up and local hygiene have been advocated by some authors, severe forms of MRONJ are not responsive to conservative therapy. At present, there is no "gold standard" therapy for this condition. However, as the physiopathological basis of MRONJ is represented by the anti-angiogenic action of various pharmacological agents, new methods to increase and promote local angiogenesis and vascularization have recently been successfully tested in vitro, limited preclinical studies, and in a pilot clinical study. CONCLUSIONS: It appears that the best method implies application on the lesion of endothelial progenitor cells as well as pro-angiogenic factors such as Vascular Endothelial Growth Factor (VEGF) and other related molecules. More recently, scaffolds in which these factors have been incorporated have shown positive results in limited trials. However, these studies must be replicated to include a large number of cases before any official therapeutic protocol is adopted.

Intraperitoneal Loss of Pelvic Array Pin During Navigated Total Hip Arthroplasty.

Pelvic array pin placement during navigated total hip arthroplasty has been known to cause complications; however, most of them are minor. We report a 78-year-old female who underwent a routine computer-navigated total hip replacement which was subsequently complicated by complete loss of the pelvic array pin requiring retrieval via laparotomy. No structures were injured despite the surrounding urological, vascular, and visceral anatomy. The patient recovered and subsequently underwent a total hip arthroplasty without complication 6 weeks later. This case illustrates the dangers of inserting a pelvic array pin within patients with poor bone quality and highlights necessary considerations of pin design and surgical techniques to minimize this complication.

Granulicatella adiacens: An uncommon diagnosis of prosthetic hip joint infection. A case report with review of the literature.

We report a case of prosthetic hip infection in a 79 year old man caused by Granulicatella adiacens. The diagnosis was achieved using broad range 16S PCR gene analysis at an early stage, after joint aspiration and culture failed to yield a pathogen. Staged revision surgery together with administration of appropriate antibiotics resulted in cure. Granulicatella adiacens is a nutritionally variant streptococcus (NVS). It has been increasingly reported to cause significant morbidities involving various systems. Its insidious growth due to complex growth requirements, has made its diagnosis challenging, and often delays appropriate antibiotic administration.

A Narrative Review of Aspirin Resistance in VTE Prophylaxis for Orthopaedic Surgery.

Total hip arthroplasties (THA) and total knee arthroplasties (TKA) confer one of the highest risks for developing venous thromboembolism (VTE) and pharmacological prophylaxis is imperative to help mitigate the risks. Aspirin is the most cost-effective medication for VTE prophylaxis, and its use post-THA/TKA has grown in popularity. Aspirin resistance is categorised as clinical or laboratory resistance with obesity, advancing age, diabetes mellitus, dyslipidaemia and inflammatory diseases identified as risk factors for aspirin resistance. Treatment failure due to aspirin resistance has been reported in cardiovascular and cerebrovascular disease leading to increased rates of mortality and re-embolisation. However, aspirin resistance in patients undergoing a THA/TKA has not been described, nor has there been investigation into the incidence rates or clinical outcomes. The aim of this narrative review is to appraise the concept of aspirin resistance in the context of aspirin use for VTE prophylaxis after THA/TKA surgeries. This is important to investigate as the risk factors for aspirin resistance, including obesity, advancing age, diabetes mellitus, dyslipidaemia and inflammatory diseases, are also risk factors for THA/TKA and risk factors for VTE. The presence of aspirin resistance in patients undergoing orthopaedic surgery may place patients at greater risk of thrombotic events if aspirin is prescribed for VTE prophylaxis. This could further increase the risk of complications associated with VTE and potential long-term consequences such as post-thrombotic syndrome. Future research is required to explore and quantify the rates of aspirin resistance and the clinical outcomes in orthopaedic patients; especially in those patients with these overlapping risk factors for THA/TKA, VTE and aspirin resistance.

Improving operating theatre communication between the orthopaedics surgeon and radiographer.

OBJECTIVES: This study was designed to assess the importance of communication between surgeons and radiographers in the operation of image intensifiers during orthopaedic surgery. METHODS: This study was designed and conducted as single-centre, observational study. Fifteen medical officers and 15 radiographers were involved in this study. Each of the 15 radiographers was assigned to a medical officer. The 15 pairs were then each given a task to simulate achieving 'perfect circles' on fluoroscopy for distal locking of an intramedullary nail. The time taken for the surgeon to verbally instruct the radiographer how to position the image intensifier in order to achieve 'perfect circles' was recorded. The overall time taken to perform the task, and total number of images taken was recorded before and after a terminology system to manoeuvre image intensifier was introduced to the pairs. RESULTS: The mean time taken for the pairs to achieve perfect circles after the introduction of the manoeuvre terminology showed statistically significant reduction from 212 to 97 s (t = 4.212, df = 88, P < 0.05) after the introduction of the terminology. The mean number of fluoroscopy exposures taken also showed a statistically significant reduction from 12 to 6 (t = 6.791, df = 88, P < 0.05). CONCLUSION: The implementation of a clear and unambiguous set of commands to control the image intensifier, which are common to both surgeon and radiographer, can reduce the time to acquire the desired images, and requires less radiation exposure in the process.

Outcome of revision total knee arthroplasty with bone allograft in 30 cases.

Revision Total Knee Arthroplasty is often complicated by large bone defects in the distal femur and proximal tibia. These defects can be managed in a variety of ways including the use of allograft bone. The purpose of this study was to retrospectively evaluate the clinical outcome of revision total knee arthroplasty cases where allograft bone was used. Thirty revision TKA's (27 patients) performed between 1994 and 2009 were followed for a mean of 5 years (1-14 years). Preoperative bone defects were classified using the Anderson Orthopaedic Research Institute classification system. Patient follow-up entailed calculation of the Knee Society Score and radiological assessment of the revision joint replacement in addition to review of complications. Kaplan Meier analysis predicted survivorship at 5 years as 93%, with further revision surgery as end point. The average Knee Society Score was 76.4, with 19 (63%) of knees scoring "excellent" results, 4 (14%) "good", 1 (3%) "fair" and 6 (20%) were "poor". The overall complication rate was 233%. Radiological lucency was demonstrated on recent radiographs for one patient. Three knees were re-revised at 1 year, 6 years and 8 years respectively. Our study demonstrates promising short to medium term results with the use of allograft bone in revision total knee replacement presenting with significant bone loss.

The use of Gamma-irradiated proximal femoral allografts for bone stock reconstruction in complex revision hip arthroplasty.

We have followed a consecutive series of 49 revision hip arthroplasties, performed for severe femoral bone loss using Gamma-irradiated anatomic-specific proximal femoral allografts longer than five centimetres. The patients were followed for a median 10.2 years, with a five year minimum follow-up. The median preoperative Harris Hip Score (HHS) improved from 42 points to 77 points postoperatively. In four hips the femoral component was further revised for non-union of the allograft and aseptic failure. In one hip the allograft and the femoral component were removed because of infection. In one hip the allograft and the femoral component were re-revised for host step-cut fracture. Junctional-union was observed in 44/49 hips. By defining success as an increase of HHS by 20 points or more, a stable implant and no need for any subsequent re-operations related to the allograft and /or the implant, a success rate of 76% was observed. Kaplan-Meier survivorship analysis predicted 79% rate of survival at 10 years and 75% rate of survival at 17 years, with the need for further revision of the allograft and/or implant as the end point. Three hips underwent re-attachment of the greater trochanter for trochanteric escape. Asymptomatic non-union of the greater trochanter was noticed in another three hips. Moderate allograft resorption was observed in four hips. Two fractures of the host step-cut occurred. There were four dislocations. Good long-term results with the use of large anatomic-specific femoral allografts justify their continued use in cases of revision hip arthroplasty complicated with severe femoral bone loss.

Arthroscopic lavage for the treatment of septic arthritis of the hip in children.

Arthroscopic treatment of septic arthritis of the hip is still not an established technique despite its minimally invasive nature and low morbidity. The goal of this study is to present the results of arthroscopic drainage and lavage for the treatment of septic arthritis of the hip in children over the age of six years. A three portal arthroscopic technique was used for drainage and irrigation in six children with septic coxitis. Continuous intra-articular irrigation was not performed, nor were decompression drains used. All patients were treated with intravenous antibiotics, followed by oral antibiotics. The children were followed for 14 to 84 months. Staphylococcus Aureus was the infecting organism in all cases. All patients had a rapid postoperative recovery; they all had excellent clinical and radiological results. All of them had a full range of motion of the affected hip. No complications occurred in this group of children. Three directional arthroscopic surgery combined with large volume irrigation appeared as an effective treatment modality in cases of septic arthritis of the hip. It is less invasive than arthrotomy, and offers low post surgical morbidity.

A modified cementing technique using BoneSource to augment fixation of the acetabulum in a sheep model.

BACKGROUND AND PURPOSE: Our aim was to assess in an animal model whether the use of HA paste at the cement-bone interface in the acetabulum improves fixation. We examined, in sheep, the effect of interposing a layer of hydroxyapatite cement around the periphery of a polyethylene socket prior to fixing it using polymethylmethacrylate (PMMA). METHODS: We performed a randomized study involving 22 sheep that had BoneSource hydroxyapatite material applied to the surface of the acetabulum before cementing a polyethylene cup at arthroplasty. We studied the gross radiographic appearance of the implant-bone interface and the histological appearance at the interface. RESULTS: There were more radiolucencies evident in the control group. Histologically, only sheep randomized into the BoneSource group exhibited a fully osseointegrated interface. Use of the hydroxyapatite material did not give any detrimental effects. In some cases, the material appeared to have been fully resorbed. When the material was evident in histological sections, it was incorporated into an osseointegrated interface. There was no giant cell reaction present. There was no evidence of migration of BoneSource to the articulation. INTERPRETATION: The application of HA material prior to cementation of a socket produced an improved interface. The technique may be useful in humans, to extend the longevity of the cemented implant by protecting the socket interface from the effect of hydrodynamic fluid flow and particulate debris.

Arthroscopic treatment of septic arthritis of the hip.

Arthrotomy is considered standard treatment for septic arthritis of the hip; the procedure may be complicated by avascular necrosis or postoperative hip instability. Arthroscopic treatment of patients with this condition is still not an established technique, despite its minimally invasive nature and the fact that it is associated with low morbidity. A 3-portal arthroscopic technique by Byrd with the patient in the supine position was used for drainage, debridement, and irrigation in 6 patients with septic coxarthrosis. Continuous postoperative intra-articular irrigation was not provided, nor were postoperative decompression drains used. All patients were treated with intravenous antibiotics for 3 weeks, followed by oral antibiotics for an additional minimum of 3 weeks. Patients were followed for 6 to 42 months. Staphylococcus aureus was identified in 4 of the 6 patients. All patients had a rapid postoperative recovery. Mean Harris Hip Score at the last review was 97.5 points. All patients showed full range of motion of the affected hip. No complications occurred with this group of patients. Thus, 3-directional arthroscopic surgery combined with large-volume irrigation is an effective treatment modality in cases of septic arthritis of the hip. It is less invasive than arthrotomy and offers low rates of postsurgical morbidity.

Structural allografts for bone stock reconstruction in two-stage revision for infected total hip arthroplasty: good outcome in 16 of 18 patients followed for 5-14 years.

BACKGROUND: The use of massive bone allografts in cases of revision of failed total hip arthroplasties (THAs) due to infection is controversial. PATIENTS AND METHODS: 18 patients presented with infection at the site of a THA and were treated with a two-stage protocol. In the first stage, the prosthesis was removed together with all necrotic tissues and cement material if present. A custom-made mold of Palacos R cement containing 1 g of gentamicin was then inserted in 17 of the 18 patients. Systemic antibiotics were used during the interval period. In the second stage, the patients had either acetabular or femoral reconstruction using bulk allograft bone. RESULTS: Mean follow-up was 9 (5-14) years. 1 patient presented with recurrent infection and underwent a Girdlestone resection arthroplasty as definitive treatment. Another patient had a mechanical failure of the acetabular component, which was revised 10 years after the second stage of the reconstruction. The mean Harris Hip Score improved from 34 points preoperatively to 71 points at the last review. By our definition, 16/18 of the patients had a successful outcome. INTERPRETATION: Our results support the use of massive allografts in staged reconstructions of infected THAs complicated by considerable bone loss.

Metal debris from bony resection in knee arthroplasty--is it an issue?

BACKGROUND: Metal particles are generated during bone preparation in knee arthroplasty. These particles may produce third-body wear, or may have a role in osteolysis. Knowledge of their characteristics may help in the development of methods to reduce the amount of metal debris during bone cutting procedures. MATERIAL AND METHODS: We performed bony resection of the distal femur and proximal tibia on 15 pig knees, simulating a total knee arthroplasty (TKA). Metal debris was collected from the saw blades, cutting blocks and bone surfaces and cleaned for microanalysis. RESULTS: The average loss of metal from the saw blades was 1.13 mg. The average volume of a wear particle was 3.4 x 10(-16) m(3). From this, it was estimated that approximately 500,000 particles are released from the saw blade alone. Material analysis of the particles indicated that the majority originated from the metallic cutting guides, suggesting that many millions of wear particles would be generated during the surgical procedure. Two particle shapes predominated: platelet shape and ploughed shape. INTERPRETATION: Wear particles are produced during resection for a TKA. These may enter the artificial articulation and cause accelerated wear and macrophage activation. Redesign of cutting blocks and saw blades may reduce the amount of debris produced during surgery.