Neck narrowing in resurfacing hip arthroplasty: a vascular insult?

INTRODUCTION: Recent reports show increased failure rates in hip resurfacings that display >10 % neck narrowing. The etiology of neck narrowing remains unknown. METHODS: We assessed 80 hip resurfacings at mean 3.5 years follow-up. RESULTS: The overall rate of significant narrowing was 11.25 %. Neck narrowing occurred in 4 % of patients using an anterolateral approach and 23.3 % using a posterior approach (P = 0.019). Logistic regression showed that both surgical approach and cup inclination angle were the most important risk factors for the development of narrowing. The odds of the presence of narrowing increased for every degree increase in cup abduction angle (P = 0.021). There was no significant association with age, sex, pre-operative diagnosis, pre- and post-operative SF-36 scores, neck shaft angle, femoral or acetabular component sizes. CONCLUSION: We postulate that neck narrowing is a result of damage to the medial circumflex femoral vessel when resurfacing through a posterior approach.

Gitelman's syndrome: a rare presentation mimicking cauda equina syndrome.

We describe a case of bilateral weakness of the lower limbs, sensory disturbance and intermittent urinary incontinence, secondary to untreated Gitelman's syndrome, in a 42-year-old female who was referred with presumed cauda equina syndrome. On examination, the power of both legs was uniformly reduced, and the perianal and lower-limb sensation was altered. However, MRI of the lumbar spine was normal. Measurements of serum and urinary potassium were low and blood gas analysis revealed metabolic alkalosis. Her symptoms resolved following potassium replacement. We emphasise the importance of measurement of the plasma and urinary levels of electrolytes in the investigation of patients with paralysis of the lower limbs and suggest that they, together with blood gas analysis, allow the exclusion of unusual causes of muscle weakness resulting from metabolic disorders such as metabolic alkalosis.

Comparison of acetabular reamings during hip resurfacing versus uncemented total hip arthroplasty.

PURPOSE: To compare the quantity of bone removed from the acetabulum during resurfacing hip arthroplasty versus uncemented total hip arthroplasty (THA). METHODS: 62 consecutive patients with osteoarthritis of the hip were prospectively studied. 24 men and 7 women aged 40 to 86 (mean, 59) years underwent Birmingham hip resurfacing. 13 men and 18 women aged 34 to 88 (mean, 61) years underwent uncemented THA using the trident acetabular cup. Obese elderly women at risk of femoral neck fracture and patients with large subchondral pseudocysts or a history of avascular necrosis of the femoral head were assigned to uncemented THA. Acetabular reamings were collected; marginal osteophytes were not included. The reamings were dehydrated, defatted, and weighed. RESULTS: The mean weight of acetabular reamings was not significantly different between patients undergoing hip resurfacing and uncemented THA (p=0.57). CONCLUSION: In hip resurfacing, the use of an appropriately small femoral component avoids oversizing the acetabular component and removal of excessive bone stock.

A clinical test to avoid sural nerve injuries in percutaneous Achilles tendon repairs.

Percutaneous repairs of Achilles tendon ruptures has gained popularity due the reduced incidence of wound complications, however its use is still limited by the high incidence of sural nerve injuries associated with these repairs. The only technique described to avoid this adverse event is to surgically expose the nerve peri-operatively. In our study, we describe and validate a clinical technique to identify the sural nerve. The sural nerve was mapped using this technique both clinically and by Ultrasound (US) in a cohort of male subjects with intact Achilles tendons. We demonstrated an excellent correlation between the clinical and US mapping. This study demonstrates an accurate and repeatable clinical technique for mapping the sural nerve in conjunction with percutaneous Achilles tendon repairs.

Odontoid lateral mass asymmetry: do we over-investigate?

OBJECTIVES: This study aimed to evaluate the necessity for further radiological investigation in patients with suspected traumatic rotatory subluxation of the atlanto-axial complex on plain radiography following acute cervical trauma and outline guidelines for assessment of patients with atlanto-axial asymmetry on plain radiography. METHODS: A retrospective review of all patients who had undergone atlanto-axial CT scanning as a result of radiographic C1-C2 asymmetry following cervical spine trauma. The plain x ray and CT images were reviewed retrospectively and correlated with the clinical presentation and outcome. RESULTS AND CONCLUSION: Records of 29 patients (16 men, 13 women; age range 21-44 years) were reviewed. All patients were found to have atlanto-odontoid asymmetry on the initial plain x ray. CT images of none of the patients revealed rotatory subluxation. Ten patients (32%) were found to have congenital odontoid lateral mass asymmetry. All patients were treated conservatively without any further intervention. On review, in 19 patients the orientation of the x ray beam in combination with head rotation was found to be at fault. Approximately 1050 trauma cervical spine x rays were taken in the department where this study was conducted over the period 1999-2001. This study identified 10 patients out of a total of 29 as having congenital odontoid lateral mass asymmetry. This represents approximately 1% of the patients attending the emergency department. Thus congenital odontoid lateral mass asymmetry should be considered in the differential diagnosis following acute cervical trauma.

Odontoid Lateral Mass Interval (OLMI) asymmetry and rotary subluxation: a retrospective study in cervical spine injury.

The aim of the study was to evaluate the significance of odontoid lateral mass interval (OLMI) asymmetry on open-mouth view, in neck injury patients who have otherwise normal cervical spine x-rays. Thirteen neck injury patients were reviewed. Average age was 23.5 years (range, 16-30 years) and average follow-up was 15 weeks (range, 6-39 weeks). All the patients, referred from the casualty department, had computed tomography (CT) scans because of the OLMI asymmetry to rule out rotary subluxation. Clinically none of the patients had torticollis. CT scans were reported normal except for OLMI asymmetry, in 11 patients. Two patients were reported as having rotary subluxation and one was found, after normal initial plain films, to have an undisplaced lateral mass fracture of the atlas with bony avulsion of the transverse ligament. The average OLMI asymmetry was 3.1 mm (range, 2-4 mm). The authors concluded that although OLMI asymmetry has low sensitivity and specificity for true subluxation or instability, it may be a sign of significant cervical injury and should be evaluated with CT.

Bone sialoprotein-coated femoral implants are osteoinductive but mechanically compromised.

Aseptic loosening of femoral implants in total hip replacement remains an unsolved orthopaedic problem. This paper investigates the potential role of bone sialoprotein (BSP) in enhancing bone-implant adherence. As BSP is osteoinductive in rat calvarial models, we investigated whether BSP is similarly osteoinductive when coated onto intramedullary femoral implants. BSP-coated titanium implants were implanted into the femur of female 'Wistar' rats (average weight 215 g) that were sacrificed at days 10, 20 and 30. Harvested femoral implants were subjected to pullout testing and then examined histologically. BSP-coated implants demonstrate osteoinduction when examined histologically. Plugging the femoral canal with BSP prior to inserting the implant neither increased implant pullout strengths nor further increased osteoblastic activity. This study has demonstrated for the first time that BSP is osteoinductive when coated onto femoral implants and inserted into bones subjected to mechanical loading. However, we found that pullout strengths are a function of implant surface topographical characteristics and are not affected by BSP coating or histological osteoinduction.

K-wire position in tension band wiring of the olecranon - a comparison of two techniques.

Tension band wiring is a recognised standard treatment for olecranon fractures. We studied the effect of K-wire position on backing out of the wire in a group of 80 patients with closed transverse olecranon fractures with a minimum follow-up time of 9 months. The rate of wires backing out as seen on X-ray was three times greater in patients who had K-wires passed down the long axis of the ulna rather than across the anterior cortex as recommended by the AO group. There was a corresponding higher rate of local complications in these patients. 42% of this group had to have the metal removed compared with 11.4% of the transcortical group. We compared the biomechanical properties of both K-wires positions in a human cadaveric model. The maximum pull-out strength for each configuration was recorded in 20 elbow joints. The average maximum pullout strength for the intramedullary wires was 56.3 N (range 27. 7-95.6 N) and 122.7 N for the transcortical wires (range 56.7-201.2). The results of both the clinical study and biomechanical data support the routine use of transcortical placement of K-wires in tension-band wiring of transverse olecranon fractures.

The unstable distal radial fracture one year post Kapandji intrafocal pinning.

Kapandji pinning has been proposed as the treatment of choice for unstable Colles' fractures. The aim of this paper is to evaluate our experience treating unstable Colles' type fractures using this technique. Over a nine month period, 36 patients with Colles' type fractures were treated operatively at St. Vincent's Hospital. 22 of these fractures were deemed unstable and were treated using percutaneous intrafocal Kapandji pinning. 20 of these patients were recalled for review at a mean of 11.3 month post injury. At this stage the wrist was examined clinically and radiologically. Initial satisfactory correction of deformity was achieved by this technique. Between the time of wire removal and final review, however, there was significant recurrence of dorsal angulation (P < 0.05), but no significant radial shortening on radiographs. The patients had a satisfactory clinical result in spite of these radiological parameters.

Fractures of the capitellum--a comparison of two fixation methods.

Isolated capitellar fractures are rare, accounting for only 1 per cent of all elbow fractures (Bryan and Morrey, The Elbow and its Disorders, 1985). Many different fixation methods have been described but no series has compared these treatment modalities because of the rarity of these fractures. This paper compares the outcome of two types of fixation of type I capitellar fractures. Group one (n = 6) had open reduction and Kirschner wire fixation while group two (n = 6) had open reduction and Herbert screw fixation. Both groups were compared clinically, functionally and radiographically. We found that Herbert screw fixation enabled earlier mobilization and a better functional outcome.

A no-touch technique of loading bone cement for gun injection at total hip arthroplasty.

Cement guns are widely used to introduce bone cement into the proximal femur at total hip arthroplasty. Loading these devices is cumbersome. A convenient technique for filling cement gun inserts is described.

Percutaneous screw fixation of tibial plateau fractures.

A series of 13 patients with displaced fractures of the tibial plateau treated by closed reduction and percutaneous pinning have been reviewed 17 months after surgery. All the operations were performed using image intensification to aid reduction of the fracture by ligamentotaxis and to guide screw placement. In two cases, arthroscopy was used in addition to facilitate elevation of the articular surface using a probe inserted through a cortical window in the proximal tibial metaphysis. The postoperative rehabilitation programme consisted of early mobilization and non-weight bearing for at least 2 months. Of the patients, 11 had a satisfactory result, one patient had a fair result with persistent pain and the other had a poor result when the fixation failed in a comminuted bicondylar fracture in porotic bone. This technique is minimally invasive and avoids many of the complications of both conservative and operative treatment and will have an expanding role to play in the management of these fractures.

Long-term outcome of articular fractures of the phalanges: an eleven year follow up.

Fifty-four patients with fifty-nine intra-articular fractures of the phalanges have been followed prospectively for eleven years, at the end of which time only four had significant pain and sixteen others discomfort in cold weather. Improvement in the symptoms and in the range of motion often continued for more than a year after injury. Although 17% of joints developed minor osteophytes or cysts, only one had both radiological evidence of arthritis and persistent pain.

Legg-Calvé-Perthes disease in a family: genetic or environmental.

This is a case report of a family in which Legg-Calvé-Perthes disease (LCPD) occurred in four members. All the patients were male and between the ages of three and eight years. This unusually high incidence in one family raises questions about the genetic versus the environmental factors in the etiology of LCPD.

Acute osteomyelitis of the ilium.

Acute osteomyelitis of the ilium is rare and early diagnosis is uncommon. A successfully diagnosed case is presented and its misleading symptomatology discussed. Delay in diagnosis can only be avoided by clinical awareness of its existence and knowledge of its varied presentation.