Anatomical considerations of C2 lamina for the placement of translaminar screw: a review of the literature.

PURPOSE: The thorough knowledge of C2 lamina anatomy is essential for the avoidance of complications during screw fixation. We performed a review of the literature, aiming to detect what was found about anatomical feasibility of C2 translaminar fixation in different populations, along with possible recommendations for the avoidance of complications, and to detect whether factors such as race or gender could influence axis lamina anatomy and fixation feasibility. METHODS: We performed a search in PubMed and Cochrane database of systematic reviews for studies which correlated axis lamina anatomy with fixation feasibility. We extracted data concerning measurements on C2 lamina, the methods and conclusions of the studies. RESULTS: Twenty-six studies met our inclusion criteria. The studies mainly focused on Asian populations. Male gender was generally related to larger anatomical parameters of C2 lamina. The use of a C2 translaminar screw with a diameter of 3.5 mm was generally feasible, even in children, but there was disagreement about risk of vertebral artery injury. Computed tomography was most frequently recommended preoperatively. Three-dimensional reconstruction was suggested by some authors. CONCLUSION: C2 lamina anatomy generally permitted screw fixation in most studies, but there was disagreement about risk of vertebral artery injury. Preoperative computed tomography was generally recommended, while, according to some authors, three-dimensional reconstruction could be essential. However, there is a relative lack of studies about non-Asian populations. More research could further illustrate the anatomy of C2 lamina, clarify the safety of axis fixation for more populations and perhaps modify preoperative imaging protocols.

High complication rate in reconstruction of Paprosky type IIIa acetabular defects using an oblong implant with modular side plates and a hook.

We report the results of 62 hips in 62 patients (17 males, 45 females) with mean age of 62.4 years (37 to 81), who underwent revision of the acetabular component of a total hip replacement due to aseptic loosening between May 2003 and November 2007. All hips had a Paprosky type IIIa acetabular defect. Acetabular revision was undertaken using a Procotyl E cementless oblong implant with modular side plates and a hook combined with impaction allografting. At a mean follow-up of 60.5 months (36 to 94) with no patients lost to follow-up and one died due to unrelated illness, the complication rate was 38.7%. Complications included aseptic loosening (19 hips), deep infection (3 hips), broken hook and side plate (one hip) and a femoral nerve palsy (one hip). Further revision of the acetabular component was required in 18 hips (29.0%) and a further four hips (6.4%) are currently loose and awaiting revision. We observed unacceptably high rates of complication and failure in our group of patients and cannot recommend this implant or technique.

Large diameter femoral heads impose significant alterations on the strains developed on femoral component and bone: a finite element analysis.

Total Hip Arthroplasty aims at fully recreating a functional hip joint. Over the past years modular implant systems have become common practice and are widely used, due to the surgical options they provide. In addition Big Femoral Heads have also been implemented in the process, providing more flexibility for the surgeon. The current study aims at investigating the effects that femoral heads of bigger diameter may impose on the mechanical behavior of the bone-implant assembly. Using data acquired by Computed Tomographies and a Coordinate Measurement Machine, a cadaveric femur and a Profemur-E modular stem were fully digitized, leading to a three dimensional finite element model in ANSYS Workbench. Strains and stresses were then calculated, focusing on areas of clinical interest, based on Gruen zones: the calcar and the corresponding below the greater trochanter area in the proximal femur, the stem tip region and a profile line along linea aspera. The performed finite elements analysis revealed that the use of large diameter heads produces significant changes in strain development within the bone volume, especially in the lateral side. The application of Frost's law in bone remodeling, validated the hypothesis that for all diameters normal bone growth occurs. However, in the calcar area lower strain values were recorded, when comparing with the reference model featuring a 28mm femoral head. Along line aspera and for the stem tip area, higher values were recorded. Finally, stresses calculated on the modular neck revealed increased values, but without reaching the yield strength of the titanium alloy used.

An examination of the association between different morphotypes of femoroacetabular impingement in asymptomatic subjects and the development of osteoarthritis of the hip.

We retrospectively examined the long-term outcome of 96 asymptomatic hips in 96 patients with a mean age of 49.3 years (16 to 65) who had radiological evidence of femoroacetabular impingement. When surveillance commenced there were 17, 34, and 45 hips with cam, pincer, and mixed impingement, respectively. Overall, 79 hips (82.3%) remained free of osteoarthritis for a mean of 18.5 years (10 to 40). In contrast, 17 hips (17.7%) developed osteoarthritis at a mean of 12 years (2 to 28). No statistically significant difference was found in the rates of development of osteoarthritis among the three groups (p = 0.43). Regression analysis showed that only the presence of idiopathic osteoarthritis of the contralateral diseased hip was predictive of development of osteoarthritis on the asymptomatic side (p = 0.039). We conclude that a substantial proportion of hips with femoroacetabular impingement may not develop osteoarthritis in the long-term. Accordingly, in the absence of symptoms, prophylactic surgical treatment is not warranted.

Trochanteric osteotomy in total hip replacement for congenital hip disease.

We studied the effect of trochanteric osteotomy in 192 total hip replacements in 140 patients with congenital hip disease. There was bony union in 158 hips (82%), fibrous union in 29 (15%) and nonunion in five (3%). The rate of union had a statistically significant relationship with the position of reattachment of the trochanter, which depended greatly on the pre-operative diagnosis. The pre-operative Trendelenburg gait substantially improved in all three disease types (dysplasia, low and high dislocation) and all four categories of reattachment position. A persistent Trendelenburg gait post-operatively was noticed mostly in patients with defective union (fibrous or nonunion). Acetabular and femoral loosening had a statistically significant relationship with defective union and the position of reattachment of the trochanter. These results suggest that the complications of trochanteric osteotomy in total hip replacement for patients with congenital hip disease are less important than the benefits of this surgical approach.

Prevention of heterotopic ossification in cases of hypertrophic osteoarthritis submitted to total hip arthroplasty. Etidronate or Indomethacin?

We present a study comparing etidronate or indomethacin for the prevention of heterotopic ossification after total hip arthroplasty in patients with hypertrophic osteoarthritis. 52 patients were divided in two groups. Group A (26 patients) received etidronate (20 mg/kg/day for 12 weeks) and Group B (26 patients) indomethacin 75 mg/day for 2 weeks. Mean follow up was 36 months (range, 18 to 50 months). The incidence of side effects was 15.4% in group A and 30.8% in group B (p=0.324). At 6 months there was no statistically significant difference in terms of clinical (p=0.532) and radiographic evaluation between the two groups (p=0.303). However, the cost of etidronate which may be as much as six times more expensive than that of indomethacin could not justify its routine prophylactic use.

Proximal femoral allograft-prosthesis composites in revision hip replacement: a 12-year follow-up study.

We report the use of an allograft prosthetic composite for reconstruction of the skeletal defect in complex revision total hip replacement for severe proximal femoral bone loss. Between 1986 and 1999, 72 patients (20 men, 52 women) with a mean age of 59.9 years (38 to 78) underwent reconstruction using this technique. At a mean follow-up of 12 years (8 to 20) 57 patients were alive, 14 had died and one was lost to follow-up. Further revision was performed in 19 hips at a mean of 44.5 months (11 to 153) post-operatively. Causes of failure were aseptic loosening in four, allograft resorption in three, allograft nonunion in two, allograft fracture in four, fracture of the stem in one, and deep infection in five. The survivorship of the allograft-prosthesis composite at ten years was 69.0% (95% confidence interval 67.7 to 70.3) with 26 patients remaining at risk. Survivorship was statistically significantly affected by the severity of the pre-operative bone loss (Paprosky type IV; p = 0.019), the number of previous hip revisions exceeding two (p = 0.047), and the length of the allograft used (p = 0.005).

Distal tibial fractures treated with hybrid external fixation.

Management of distal tibia fractures remains challenging. The purpose of this study was to evaluate whether hybrid external fixation, as definite treatment, was associated with satisfactory results and low rate of complications. Between November 1999 and October 2006, 48 patients (33 men and 15 women) with a mean age of 45.6 years and a median ISS of 14.3 were admitted to our department with a distal tibia fracture and treated with the use of a hybrid external fixator. Eight patients had an open fracture. Mean follow-up was 14 months (range, 9-36 months). In 40 patients, radiographic evidence of union was observed at 3.6 months (range, 3-6 months). Delayed union was observed in three patients. There were five non-unions (10.4%) with three of them were septic. When compared to previously reported series, with conventional open reduction and internal fixation, the use of hybrid external fixation with or without open reduction and internal fixation of the fibula, was associated with satisfactory clinical and radiographic results and limited complications.

Biology of implant osseointegration.

Osseointegration refers to a direct structural and functional connection between ordered, living bone and the surface of a load-carrying implant. Currently, an implant is considered as osseointegrated when there is no progressive relative movement between the implant and the bone with which it has direct contact. A direct bone contact as observed histologically may be indicative of the lack of a local or systemic biological response to that surface. It is therefore proposed that osseointegration is not the result of an advantageous biological tissue response but rather the lack of a negative tissue response. The rationale of the present review is to evaluate the basic science work performed on the concept of biology of osseointegration, and to discuss the specific factors as they may relate to osseous healing around an implant.

Reliability and validity of the Hartofilakidis classification system of congenital hip disease in adults.

The reliability and validity of the Hartofilakidis et al. classification system in adults with congenital hip disease (CHD) were examined. The radiographs of 102 adult patients (158 hips) with CHD were independently assessed by three senior surgeons. Interobserver variability was assessed by examining the agreement between the three raters while validity of the classification system was assessed by examining the agreement between the assessment by either one of the three raters and the intraoperative finding (reference standard). The interobserver agreement between the three observers was high ranging from 0.720 to 0.854 (substantial to excellent) while the agreement of the preoperative prediction with the intraoperative findings was 87.4% (K = 0.823, excellent agreement). The Hartofilakidis et al. classification system reliably predicts from preoperative pelvis radiographs the bone deficiencies encountered during the operation.

Evaluation of two surgical techniques for acetabular reconstruction in total hip replacement for congenital hip disease: results after a minimum ten-year follow-up.

We have evaluated the results of total hip replacement in patients with congenital hip disease using 46 cemented all-polyethylene Charnley acetabular components implanted with the cotyloplasty technique in 34 patients (group A), and compared them with 47 metal-backed cementless acetabular components implanted without bone grafting in 33 patients (group B). Patients in group A were treated between 1988 and 1993 and those in group B between 1990 and 1995. The mean follow-up for group A was 16.6 years (12 to 18) and the mean follow-up for group B was 13.4 years (10 to 16). Revision for aseptic loosening was undertaken in 15 hips (32.6%) in group A and in four hips (8.5%) in group B. When liner exchange was included, a total of 13 hips were revised in group B (27.7%). The mean polyethylene wear was 0.11 mm/yr (0.002 to 0.43) and 0.107 mm/yr (0 to 0.62) for groups A and B, respectively. Polyethylene wear in group A was associated with linear osteolysis, and in group B with expansile osteolysis. In patients with congenital hip disease, when 80% cover of the implant can be obtained, a cementless acetabular component appears to be acceptable and provides durable fixation. However, because of the type of osteolysis arising with these devices, early exchange of a worn liner is recommended before extensive bone loss makes revision surgery more complicated.

Biomaterial osseointegration enhancement with biophysical stimulation.

Despite the ongoing improvement in implant characteristics, bone intrinsic potential for regeneration may be stimulated with adjuvant therapies to standard surgical procedures, as it is important to achieve the best possible implant osseointegration into the adjacent bone and to ensure therefore long-term implant stability. For this purpose various pharmacological, biological or biophysical modalities have been developed, such as bone grafting materials, pharmacological agents, growth factors and bone morphogenetic proteins. Biophysical stimulation of osseointegration includes two non-invasive and safe methods that have been initially developed to enhance fracture healing: pulsed electromagnetic fields (PEMFs) and lowintensity ultrasounds (LIPUS), for which most studies confirm their beneficial effects. The present paper is an overview of bone-implant osseointegration and the current trends on its enhancement, focusing mainly on the two methods of biophysical stimulation.

Poor outcomes of isolated tibial insert exchange and arthrolysis for the management of stiffness following total knee arthroplasty.

BACKGROUND: Severe stiffness after total knee arthroplasty is a debilitating problem. In patients with securely fixed and appropriately aligned components, arthrolysis of adhesions and exchange to a thinner tibial polyethylene insert may appear to be a reasonable and logical solution. We reviewed our experience with this procedure to determine its efficacy. METHODS: From 1992 through 1998, seven knees with marked stiffness after total knee arthroplasty were treated at our institution with arthrolysis of adhesions and conversion to a thinner tibial polyethylene insert. Only patients in whom the total knee prosthesis was well aligned, well fixed, and not associated with infection were included. There were five women and two men with a mean age at revision of sixty-one years (range, thirty-eight to seventy-four years). The average time to revision was twelve months, and the mean arc of motion prior to revision was 38.6 degrees (range, 15 degrees to 60 degrees ). The duration of follow-up after the insert exchange averaged 4.2 years (range, two to eight years). RESULTS: Mean Knee Society pain and function scores changed from 44 and 36.4 points preoperatively to 39.6 and 46 points at the time of final follow-up. Two knees were rerevised, one because of infection and the other because of aseptic loosening of the components. The five remaining knees were painful and stiff at the time of final follow-up. Four of these five knees were severely painful, and one knee was moderately and occasionally painful. The mean arc of motion of these five knees was 58 degrees (range, 40 degrees to 70 degrees ) at the time of final follow-up. CONCLUSION: Isolated tibial insert exchange, arthrolysis, and débridement failed to provide a viable solution to the difficult and poorly understood problem of knee stiffness in a group of carefully selected patients following total knee arthroplasty. We therefore have little enthusiasm for the continued use of this strategy.

Fixation of femoral shaft fractures with a flexible bundle-type nail.

In a prospective study, 31 consecutive patients with a femoral shaft fracture were treated with the Marchetti-Vicenzi intramedullary flexible bundle-type nail. Open reduction of the fracture was necessary in 25 of the 31 patients (81%). Twenty-five of the 31 fractures (81%) united within 2.5 to 6 months after the operation (mean, 4.2 months). Nonunion occurred in one patient (3.2%). Other complications included delayed union in five patients (16%), femoral shortening in five (16%), breakage of the distal pins in two (6.5%), and severe varus malunion in two patients (6.5%). Because of the high complication rate in this series, the authors no longer use the Marchetti-Vicenzi flexible nail for treatment of femoral shaft fractures.

Operative treatment for Maisonneuve fracture of the proximal fibula.

This study reviewed operative treatment of Maisonneuve fracture of the fibula in 26 patients. Operative treatment consisted of restoration of the fibular length, repair of the lateral and medial ankle ligamentous structures, and placement of one or two suprasyndesmotic screws. After average follow-up of 6.4 years, the clinical results were satisfactory in 23 (88.4%) patients. Operative treatment is the treatment of choice for Maisonneuve fractures, and a satisfactory outcome may be anticipated after appropriate management of any associated bony and syndesmotic injuries.

Spontaneous interbody fusion after controlled injuries to the spine: an experimental study in rabbits.

To evaluate the rationale of spontaneous spine fusion after a spinal injury, the authors conducted an experimental study that consisted of three types of controlled injuries to a rabbit spine model. The first was injury to the intervertebral disk (type I injury). The second was injury of the intervertebral disk along with injury to one of the adjacent vertebral end plates (type II). In type III injury, both the opposing end plates were injured along with the intervertebral disk. In 38 rabbits, a total of 82 injuries of these three types were inflicted. Twenty-six injuries were of type I (n = 22 rabbits), 26 were type II (n = 24 rabbits), and 30 were type III (n = 26 rabbits). Spontaneous fusion occurred only in type III injuries. From the 30 type III injuries, fusion occurred in 20 (66.6%). For an autofusion to occur, both epiphyseal plates may be injured. In the clinical situation, this observation suggests that a radiographically obscure lesion of both neighboring vertebrae may proceed to autofusion of that spinal segment observed later.

Hydatid disease of bones and joints. 8 cases followed for 4-16 years.

Hydatid disease is a rare parasitic disease that seldom involves the skeleton. Treatment is difficult because of problems with the preoperative diagnosis, the invasive nature of the bony involvement and the variable anaphylactic reaction to the cyst fluid antigen. We present 8 cases with osseous hydatidosis who were treated over a period of 11 years. The spine was involved in 2 cases, the ilium in 2, the hip in 2, the tibia in 1 and the humerus in 1. We point out that diagnosis is difficult and the prognosis is often poor.

The significance of rotation in fracture-separation of the articular pillar of a lower cervical vertebra. A clinical and cadaveric study.

We report 13 fracture-separations of an articular pillar at the lower cervical spine in 12 patients. There were 9 men and 3 women with a mean age at injury of 32 years, with involvement of C4, C5 and C6 vertebrae. Neurological symptoms were present in 9 patients, 2 were classified as ASIA A and 7 as ASIA D. The average magnitude of rotation of the articular pillar was 24 degrees (10 degrees-36 degrees). 4 patients with neurologic deficit and a rotated articular pillar of more than 25 degrees were operated on, while 8 patients, 3 of which had a rotation of more than 25 degrees, had closed treatment. Patients were followed from 8 months to 15 years (mean 9 years). Patients who had closed treatment and/or with a rotated fractured articular pillar of more than 25 degrees had less satisfactory results. This observation was affirmed by cadaveric studies which showed that rotation of more than 25 degrees is an additional factor of instability in a fractured articular pillar.