Late dislocation after total hip arthroplasty

Objectives: Instability after total hip arthroplasty is a troublesome complication. It commonly occurs in the first 3 postoperative months, but the risk continues over time.There are numerous treatment options, but they have relatively unpredictable outcomes. Numerous factors have been associated with dislocation, but research has mainly focused on the surgical ones. Epidemiological factors remain the subject of much debate.We aimed to establish the incidence of dislocation over time.     

Treatment of acute lunate and perilunate dislocations

Acute lunate and perilunate dislocations are uncommon but devastating carpal injuries with a guarded prognosis. This article outlines the pathoanatomy, diagnosis, indications for treatment, technique, and expected results of open reduction and internal fixation.     

Complex dorsal metacarpophalangeal joint dislocation caused by interosseous tendon entrapment: case report

We report a patient with open complex, dorsal metacarpophalangeal joint dislocation of the index finger with interposition of the first dorsal interosseous tendon and the transverse ligament of the palmar aponeurosis. To our knowledge, entrapment of the first dorsal interosseous tendon has not been reported to be the cause of irreducible dislocation of the metacarpophalangeal joint.     

Mortality following hip fracture: trends and geographical variations over the last 40 years

Hip fractures are an ever increasing cause of morbidity and mortality. Treatment of this condition requires an all-encompassing approach from prevention to post-operative care. It is important in such a situation to gather data on the incidence and trends of hip fractures to aid in the future treatment planning of this important condition. A review of all articles published on the outcome after hip fracture over a four decade period (1959-1998) was undertaken to determine any changes that had occurred in the demographics of patients and mortality over this time period. The mean age of patients sustaining hip fractures was found to be steadily increasing over the study period at a rate of 1 year of age for every 5-year time period. The mean age in the 1960s was 73 years to a mean of 79 years in the 1990s. No notable differences were seen in the proportion of male patients over the years but a definite downward trend was noticed with regard to intracapsular fractures. The mortality at 6 and 12 months after injury remained essentially unchanged over the four decades reviewed. Mortality after a hip fracture remains significant, being 11-23% at 6 months and 22-29% at 1 year from injury. Geographical variations exist in the mortality after hip fracture. More detailed international comparisons are required to determine if these differences in outcome are accounted for by the variations in the demographics of patients or due to diversities in treatment methods.     

Hemiarthroplasty of the hip for fracture-what is the appropriate sized femoral head?

INTRODUCTION: Caliper measurement of the excised femoral head is a standard technique for determination of prosthetic head size during hemiarthroplasty for displaced femoral neck fractures. OBJECTIVES: To evaluate the accuracy of the caliper method of hemiarthroplasty head sizing by comparing it to the native joint congruency (JC) at the weight bearing surface. MATERIALS AND METHODS: The diameters of femoral heads in 10 cadaver hip joints were measured by using a caliper at the head equator. Cast moulds were prepared from both the acetabulum and the femoral head in each joint. Every mould's exact spherical diameter at the weight bearing region was measured by a computerised coordinate measuring machine (MNC B231 MITUTOYO). All specimens were coded to ensure that future examination was carried out in a blind manner. Native JC mismatch was determined by subtracting the diameter of the femoral cement mould from that of the acetabular one. Similarly, JC mismatch was calculated for the caliper measurements. RESULTS: The average native JC mismatch (0.36+/-0.29mm, range 0.03-0.82mm, median 0.29mm) was found significantly smaller (p=0.03) than following caliper measurements (0.72+/-0.37mm, range 0.37-1.46mm, median 0.6mm). Routine caliper measured downward size rounding enhanced (p=0.004) this mismatch (0.98+/-0.44mm, range 0.37-1.96mm, median 1.01mm), while upward rounding (0.48+/-0.46mm, range -0.06 to 1.15mm, median 0.41mm) helped mitigate this tendency. CONCLUSIONS: Caliper measurements tend to undersize the actual sphere diameter of the femoral head at the weight bearing region. Upward rounded prosthesis should be selected in order to compensate for this propensity.     

Measuring tip-apex distance using a picture archiving and communication system (PACS)

BACKGROUND: The sliding hip screw is currently the most frequently used prosthesis used to fix trochanteric fractures of the hip. The 'tip-apex distance' (TAD) has been found to be predictive of hardware failure, with a larger TAD being associated with an increasing risk of 'cut-out'. Previous studies have either used 'hard-copy' radiographs and geometrical aids or a mixture of scanned hard-copy images and extra software to measure TAD. The current study describes a new method of tip-apex distance estimation using an entirely digital picture archiving and communication system (PACS). MATERIALS AND METHODS: Ten radiographs were measured for TAD by four surgeons of differing experience using the described measurement protocol, at two different time points (4 weeks apart). The results were then subjected to two-tailed t-tests to determine if they differed significantly. RESULTS: No tests attained significance (i.e. no statistical difference existed between the observers' measurements and no difference existed over time from a single observer's results). CONCLUSION: This study shows that TAD can be easily, accurately and, importantly, reproducibly measured using an entirely digitally based image capture and archiving system. The ease with which the measurements and calculations can be made will facilitate orthopaedic practitioners and trauma units in their auditing activities, and allows for quick TAD estimation in the 'X-ray meeting' environment.     

Posterior approach with posterior soft tissue repair in revision total hip arthroplasty

We investigated the influence of the posterior approach with soft tissue repair in revision hip arthroplasty by evaluating the rate of early posterior dislocation. Ninety-one patients (96 hips) who had undergone revision hip arthroplasty through the posterior approach were observed for 1 year or until dislocation occurred. Fifty-six revision hip arthroplasties were performed using the posterior approach with soft tissue repair technique. The results of these procedures were compared with those of 40 revision hip arthroplasties that had been performed using the posterior approach without soft tissue repair. The dislocation rate of 10.0% in 40 hips using the posterior approach without soft tissue repair was reduced to 1.9% in 56 hips using the posterior approach with soft tissue repair.     

Open reduction of a chronic proximal dislocation after total hip arthroplasty

We report an unusual case of a chronic prosthetic dislocation that was caused by the buttonholing of a prosthetic femoral head by anterior soft tissue, which impeded reduction. A surprisingly good functional result was achieved by an open reduction and revision operation on a 56-year-old man, who had a chronic dislocation of a total hip prosthesis. Successful treatment with open reduction of a chronic proximal dislocation after total hip arthroplasty has not been reported previously in the literature.     

The tantalum screw for treating femoral head necrosis: rationale and results

Femoral head necrosis (FHN) is a progressive pathology due to the failure of blood supply to the proximal femoral epiphysis, with consequent necrosis of the sub-chondral bone and collapse of the articular cartilage and loss of congruity between the head and the acetabulum. Borrowing the biological and mechanical principles from the vascularized fibular graft technique for the femoral neck, the tantalum screws have been introduced. They show an extraordinary porosity, osteoconductivity, biocompatibility and very good osteoinductivity. Vitreous tantalum can be processed to take the form of a screw, with a round medial extremity and a 25 mm threaded lateral extremity that can be inserted into the neck of the femur, thereby supporting the articular cartilage, stimulating the repair process, interrupting the interface between necrotic and healthy tissue and favoring local vascularization. We have drawn up a treatment protocol for early-stage FHN, based on the insertion of a tantalum screw into the femoral neck. The implant has a cylindrical shape, with a 10 mm diameter in the smooth part and 15 mm in the threaded part. It is available in different sizes from 70 to 130 mm, with 5 mm increments. The aim of the study is to describe the clinical and instrumental results of the tantalum screw for FHN. From June 2004 to June 2006 we performed 15 implants. The tantalum screw was inserted with an incision on the trochanteric region with traction and under X-ray control. For the clinical evaluation of the hip, we used the Harris hip score (HHS). For diagnosis and staging we used standard X-rays in two views and/or MRI, using the Steinberg classification (J Bone Joint Surg Br 77:34–41, 1995) and CT. In all cases, the osteonecrosis extended to not more than 30% of the joint surface and the cartilage was intact with no collapse. To assess the results, we compared the pre-operative and the post-operative HHS, calculated the percentage differences between the two. We then compared X-rays, CT scans and MRI before and some time after the operation to assess whether the problem had been addressed, taking into account the intracancellous edema and the possible extension of necrosis. After an average follow-up period of 15.43 ± 5.41 months, ten implants (seven patients out of ten) were examined and all but one patient showed a marked improvement in HHS (the average increase was 127.9%), with no further progression of the disease. We believe that this procedure can be suitable for young patients with limited first or second stage osteonecrosis. The objective for the foreseeable future is to resolve the pain, improve the quality of life and prevent or at least postpone arthroplasty.     

Arthrocentesis followed by intra-articular autologous blood injection for the treatment of recurrent temporomandibular joint dislocation

Temporomandibular joint (TMJ) dislocation is an excessive forward movement of the condyle beyond the articular eminence with complete separation of the articular surfaces and fixation in that position. This study was conducted to assess autologous blood injection to the TMJ for the treatment of chronic recurrent TMJ dislocation. Fifteen patients with bilateral chronic recurrent condylar dislocation were included in the study. Bilateral TMJ arthrocentesis was performed on each patient, followed by the injection of 2 ml of autologous blood into the superior joint compartment and 1 ml onto the outer surface of the joint capsule. Preoperative and postoperative assessment included a thorough history and physical examination to determine the maximal mouth opening, presence of pain and sounds, frequency of luxation, recurrence rate, and presence of facial nerve paralysis. Eighty percent of the subjects (12 patients) had a successful outcome with no further episodes of dislocation and required no further treatment at their 1-year follow-up, whereas three patients had recurrent dislocation as early as 2 weeks after treatment. Autologous blood injection is a safe, simple, and cost-effective treatment for chronic recurrent TMJ dislocation.