Aims. Accurate and precise acetabular reaming is a requirement for the press-fit stability of cementless acetabular hip replacement components. The accuracy of reaming depends on the reamer, the reaming technique and the bone quality. Conventional reamers wear with use resulting in inaccurate reaming diameters, whilst the theoretical beneficial effect of ‘whirlwind’ reaming over straight reaming has not previously been documented. Our aim was to compare the accuracy and precision of single use additively-manufactured reamers with new conventional reamers and to compare the effect of different acetabular reaming techniques. Materials and Methods. Forty composite bone models, half high-density and half low-density, were reamed with a new 61 mm conventional acetabular reamer using either straight or ‘whirlwind’ reaming techniques. This was repeated with a 61 mm single use additively-manufactured reamer. Reamed cavities were scanned using a 3D laser scanner with mean diameters of reamed cavities compared using the Mann-Whitney U test to determine any statistically significant differences between groups (p<0.05) [Fig. 1). Results.
Introduction: Revision hip implants have poorer clinical outcome than primary implants. The fixation of the implants is often compromised by the formation of an endosteal sclerotic bone rim during the process of aseptic loosening. The cracking procedure is a bone sparing, low energy surgical technique which produces a controlled local perforation of the sclerotic bone rim. In previous studies, we showed that fixation of revision implants significantly improved by the cracking technique for both titanium (Ti) and hydroxyapatite (HA) coated implants (. 1. ). In this study we compared the cracking technique with the common technique of reaming, which completely removes the sclerotic bone rim. Methods: A paired animal study (n=10), in which revision cavities was created by 20 micromotion implant systems inserted in both knees. Micromotion was 0.5mm per gait cycle. After 8 weeks revision surgery was performed. Crack revision: The splined crack tool was introduced over the implant piston with firm axial hammer blows. This producing controlled cracking and local perforation of the sclerotic endosteal rim. The tool is a 6.0 mm cylinder fitted with axially spaced 1.1 mm pointed splines (8.2 mm outer diameter).
Purpose of the study: Classically, bone grafts are harvested from the iliac crests which can provide a limited volume of graft material. Using the reaming product might help spare iliac bone. Material and method: A variable head RIA device (reaming, irrigation, aspiration) was used over the last year for ten patients who presented partial or segmental bone loss. The bone graft was constructed exclusively with the reaming produce following membrane induction using a cement scaffold. The tibia was reconstructed in nine cases and the humerus in one. Bone loss was 6 cm on average. Results: The reconstruction healed in six cases within a mean delay of 6 months; the 4 other cases are under assessment. Complementary bone was necessary to achieve healing in one case. There were no complications involving the donor site excepting transient pain at the point of insertion. Discussion: In this series associating an induced membrane and reaming produce, the time to healing appeared to be shorter than with cancellous iliac bone. The smaller size of the fragment may be a determining factor. Conclusion:
Patients with a femoral shaft fracture requiring intra-medullary nailing were recruited to investigate if the femoral canal could be a potential source of inflammatory cytokines, previously implicated in the pathogenesis of life-threatening inflammatory complications. Femoral and peripheral blood samples were obtained at the time of surgery from patients with a femoral shaft fracture requiring intramedullary nailing. The local femoral intramedullary and peripheral release of a group of ten Th1 and Th2 cytokines concentrations (IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, GM-CSF, TNF-a and IFN-g) after femoral shaft fracture and intramedullary reaming, if performed, was measured using a Human Cytokine Antibody 10-plex Bead Kit. A control group of patients(n=3) undergoing hip replacement was established to allow comparison with the normal femoral intramedullary cytokine environment. 21 patients with a femoral shaft fracture were recruited. Femoral shaft fracture caused a significant increase in the local femoral concentrations of IL-6 (median 3967pg/ml; range 128–25,689pg/ml) and IL-8 (median 238pg/ml; range 8–8,288pg/ml) compared to the femoral control group(p=0.0005 and p=0.001 respectively). No significant local femoral release of the other cytokines was demonstrated. In the patients who underwent intramedullary reaming of the femoral canal (n=6), a further significant local release of IL-6 (median post-ream 15,903pg/ml; range 1,854–44,922pg/ml) and IL-8 (median post-ream 1,443pg/ml; range 493–3,734pg/ml) was demonstrated (p=0.01 and p=0.03 respectively), thus showing that intramedullary reaming can cause a significant local inflammatory response. Femoral shaft fracture produces a local inflammatory response releasing large amounts of the cytokines IL-6 and IL-8 into the local femoral environment but not of the other Th1 and Th2 cytokines studied.
Aims. One goal of total hip arthroplasty is to restore normal hip anatomy.
The aim of this study was to compare displacement of the centre
of rotation (COR) using a standard reaming technique with a technique
in which the acetabulum was reamed immediately peripherally and
referenced off the rim. Patients and Methods. In the first cohort the acetabulum was reamed to the floor followed
by sequentially larger reamers. In the second cohort the acetabulum
was only reamed peripherally, starting with a reamer the same size
as the native femoral head. Anteroposterior pelvic radiographs were
analysed for acetabular floor depth and vertical and horizontal position
of the COR. Results. Horizontally, the mean medial displacement of the COR was 0.8
mm (standard deviation (. sd. ) 1.4) in the peripheral remaing
group and 5.0 mm (. sd. 3.30) in the standard reaming group
(p <
0.001). Vertically, the mean superior displacement of the
COR was 0.7 mm (. sd. 1.3) in the peripheral reaming group
and 3.7 mm (. sd. 2.6) in the standard reaming group (p <
0.001).
In the standard reaming group, there was a strong correlation between
the pre-operative acetabular floor depth and displacement of the
COR (p <
0.001). Conclusion.
Purpose:
Aim: To report on the bone histology of patients undergoing intramedullary stabilisation for a pathological fracture or a metastatic lesion in long bones. Materials and methods: From 1999 to 2002, 36 long bones in 29 patients (seven had stabilisation of two long bones) were stabilised with an intramedullary nail in patients with a known primary tumour. Prophylactic fixation was performed in 19 bones with metastatic tumour and in 17 for a fracture. Of the 17 fractures, 13 were considered pathological and four were simple fracture unrelated to metastasis. Thirty-three nailings were done for proximal femoral lesions and three were for the humerus.
Introduction: Intramedullary reaming has its selected indication in osteomyelitis of long bones when remnants of dead infected bone are intramedullary embedded in a endostal new bone formation. The validity of this method has not yet been proven in long-term follow-ups. We reevaluated our patients in a 10 to 15 years follow-up to look at the recurrence rate of osteomyelitis after intramedullary reaming. We were also interested in the level of activity and the ability of working in our patients today. Study design: From 1984 till 1992 forty-three patients with forty-four locations of chronic osteomyelitits of long bones were treated by intramedullary reaming. The collective consisted of 38 men and 5 women. The mean duration of the infection was 13.2 years. The causes of osteomyelitis were in 37 cases posttraumatic, in 6 cases haematogenous and one patient suffered from chronic osteomyelitis after removal of a total hip. Main locations of the focus were the diaphysis of the tibia and the femur. Intramedullary reaming was performed in patients with a infection centrally located in the bone protected by a thick periosteal new bone formation. In important endosteal bone formation a window was needed in order to pass with the guide wire for medullary reaming.
Total hip arthroplasty (THA) is one of the most common orthopedic surgeries. The procedure is sophisticated and in addition to several factors affecting the outcomes such as patient's status, surgeon's expertise and implant type, using appropriate surgical tools is necessary. Acetabular component implantation necessitates the surgeon to ream the acetabular fossa which is time consuming and devastating. Utilizing currently-used reamers (figure 1), the size of the tool must be changed repeatedly for 5–20 times within a surgery. In every stage, the size of the reamer is increased up to 1–2 mm. This tiring process takes 15–30 minutes and is associated with some injuries to the soft tissue. Furthermore, the risk of mistakes is considerable. Designing a new system which overcomes the limitations and defects with previous systemsIntroduction
Objectives
Primary stability is achieved by the press fit technique, where an oversized component is inserted into an undersized reamed cavity. The major geometric design of an acetabular shell is hemispherical type. On the other one, there are the hemielliptical type acetabular shells for enhanced peripheral contact. In the case of developmental dysplasia of the hip (DDH), the aseptic loosening may be induced by instability due to decreased in the contact area between the acetabular shell and host bone. The aim of this study was to assess the effect of reaming size on the primary stability of two different outer geometry shells in DDH models. The authors evaluated hemispherical (Continuum Acetabular Shell, Zimmer Biomet G.K.) and hemielliptical (Trabecular Metal Modular Acetabular Shell, Zimmer Biomet G.K.) acetabular shells. Both shells had a 50 mm outer diameter and same tantalum 3D highly porous surface. An acetabular bone model was prepared using a solid rigid polyurethane foam block with 20 pcf density (Sawbones, Pacific Research Laboratories Inc.) as a synthetic bone substrate. Press fit conditions were every 1 mm from 4 mm under reaming to 2 mm over reaming. To simulate the acetabular dysplasia the synthetic bone substrate was cut diagonally at 40°. Where, the acetabular inclination and cup-CE angle were assumed to 40° and 10°, respectively. Acetabular components were installed with 5 kN by a uniaxial universal testing machine (Autograph AGS-X, Shimadzu Corporation). Primary stability was evaluated by lever-out test. The lever-out test was performed in 4 mm undersized to 2 mm oversized reaming conditions. Lever out moment was calculated from the multiplication of the maximum load and the moment arm for primary stability of the shell. The sample size was 6 for each shell type.Introduction
Materials and methods
Recent trends in total hip arthroplasty (THA) have resulted in the use of larger acetabular components to achieve larger femoral head sizes to reduce dislocation, and improve range of motion and stability. Such practices can result in significant acetabular bone loss at the time of index THA, increasing risk of anterior/posterior wall compromise, reducing component coverage, component fixation, ingrowth surface and bone stock for future revision surgery. We report here on the effects of increasing acetabular reaming on component coverage and bone loss in a radiographic CT scan based computer model system. A total of 74 normal cadaveric pelves with nonarthritic hip joints underwent thin slice CT scan followed by upload of these scans into the FDA approved radiographic analysis software. Utilizing this software package, baseline three-dimensional calculations of femoral head size and acetabular size were obtained. The software was used to produce a CT scan based model that would simulate reaming and placement of acetabular components in these pelves that were 125, 133 and 150% the size of the native femoral head. Calculations were made of cross sectional area bone loss from anterior/posterior columns, and loss of component coverage with increasing size.INTRODUCTION:
METHODS:
Total Shoulder Resurfacing (TSR) provides a reliable solution for the treatment of glenohumeral arthritis. It confers a number of advantages over traditional joint replacement with stemmed humeral components, in terms of bone preservation and improved joint kinematics. This study aimed to determine if humeral reaming instruments produce a thermal insult to subchondral bone during TSR. This was tested in vivo on 13 patients (8 with rheumatoid arthritis and 5 with osteoarthritis) with a single reaming system and in vitro with three different humeral reaming systems on saw bone models. Real-time infrared thermal video imaging was used to assess the temperatures generated. Synthes Epoca instruments generated average temperatures of 40.7°C (SD 0.9°C) in the rheumatoid group and 56.5°C (SD 0.87°C) in the osteoarthritis group (p = 0.001). Irrigation with room temperature saline cooled the humeral head to 30°C (SD 1.2°C). Saw bone analysis generated temperatures of 58.2°C (SD 0.79°C) in the Synthes (Epoca) 59.9°C (SD 0.81°C) in Biomet (Copeland) and 58.4°C (SD 0.88°C) in the Depuy (CAP) reamers (p=0.12). Humeral reaming with power driven instruments generates considerable temperatures both in vivo and in vitro. This paper demonstrates that a significant thermal effect beyond the 47°C threshold needed to induce osteonecrosis is observed with humeral reamers, with little variation seen between manufacturers. Irrigation with room temperature saline cools the reamed bone to physiological levels, and should be performed regularly during this step in TSR.
Retroversion, also referred to as posterior wear of the glenoid, can make resurfacing the glenoid challenging. However, careful pre-operative planning with three dimensional CT scanning can allow central placement of the glenoid component through removal of some of the anterior bone to allow contained placement and secure fixation within the glenoid vault. Since the scapula is not a fixed skeletal structure and moves substantially on the chest wall, the actual degree of posterior wear (retroversion) frequently is the result of extraneous biomechanical forces and structures. For example, the degree of kyphosis and shape of the rib cage can have a substantial impact on the relative position of the glenoid surface as it articulates with the humerus. Attempts to totally equalise this through implant augmentation have not, to date, been shown to be effective, and in some cases can be destabilising. Restoration of enough alignment to place the implant centrally can be achieved without need for augmentation even in some very hypoplastic glenoids. The technique for this straight-forward approach will be presented, including pre-surgical planning, in some cases, patient specific instrumentation, with demonstration of functional outcomes.
Contracture of the anterior musculature causes posterior humeral head subluxation and results in a posterior load concentration on the glenoid. This reduced contact area causes glenoid wear, humeral medialisation and eventually posterior instability. After arthroplasty that does not correct for this, posterior wear stress increases in the implant, across the cement mantle and bone thus increasing the risk of aseptic loosening over time. Correction of the posterior wear pattern at the time of arthroplasty of the shoulder is recommended. Asymmetric reaming of the glenoid has been recommended as a means to correct this deformity but leads to producing a smaller glenoid which is medialised. This shortening of the glenoid causes the stabilising muscle envelope to shorten and the glenoid vault to become much smaller in volume. These potential changes may have a destabilising effect on the implant leading to early loosening and secondary failure of the prosthetic implant. Other options include using an implant to make the correction of the deformity such as augmented glenoid components. Early uses of these implants were not successful mainly due to the design flaws of the early implants. Newer implants have made design changes to overcome these early failures. CT scan evaluation is important to determine the degree of correction that is needed to balance the glenohumeral joint. Correcting the deformity and keeping the muscle envelope at the appropriate tension may lead to better long term outcomes. These implants are currently in use but long term outcome studies are not yet available to determine their ultimate values to the patients.
Proper femoral reaming is a key factor for a successful outcome in cementless hip arthroplasty. Good quality reaming minimizes risks of intra-operative femoral fracture during reaming and prevents poor fitting of the implant which can lead to subsidance of the stem postoperativly. Determining the quality of reaming is largely a subjective skill and dependant on the surgeon's experience with no documented intraoprative method to assess it objectively. We recorded and analysed the frequencies of sound signals recorded via a bone conduction microphone during reaming of the femoral canal in a series of 28 consecutive patients undergoing uncemented total hip replacement performed by same surgeon. Hammaring sound frequencies and intensity were analysed by mean of computer software. The relationship between the patterns of the recorded reaming sound frequencies compared with surgeon judgment of the reaming quality intraoparativly and post operative x rays. All patients were followed up clinically and radiologically for 2 years after surgery to determine the integrity of the fix and to evaluate the stability of the prosthesis.Introduction
Method
Intramedullary infection in long bones represents
a complex clinical challenge, with an increasing incidence due to the
increasing use of intramedullary fixation. We report a prospective
case series using an intramedullary reaming device, the Reamer–Irrigator–Aspirator
(RIA) system, in association with antibiotic cement rods for the
treatment of lower limb long bone infections. A total of 24 such
patients, 16 men and eight women, with a mean age of 44.5 years
(17 to 75), 14 with femoral and 10 with tibial infection, were treated
in a staged manner over a period of 2.5 years in a single referral
centre. Of these, 21 patients had had previous surgery, usually
for fixation of a fracture (seven had sustained an open fracture
originally and one had undergone fasciotomies). According to the
Cierny–Mader classification system, 18 patients were classified
as type 1A, four as 3A (discharging sinus tract), one as type 4A
and one as type 1B. Cite this article:
We present three young men who sustained closed diaphyseal fracture of the tibia and later developed severe osteocutaneous necrosis induced by heat during intramedullary reaming. They all had a narrow medullary cavity and in all a tourniquet had been used. Each developed a pretibial cutaneous blister soon after operation. In the following month severe osteomyelitis ensued, requiring segmental resection and osteocutaneous reconstruction.