Hip Resection Arthroplasty

The Influence of Osteon Orientation on Surface Topography Parameters after Machining of Cortical Bone Tissue

Mechanical processing of cortical bone tissue is one of the most common surgical procedures. A critical issue accompanying this processing is the condition of the surface layer, which can stimulate tissue growth and serve as a drug carrier. A comparison of the surface condition before and after orthogonal and abrasive processing was conducted to validate the influence of bone tissue's processing mechanism and orthotropic properties on the surface topography. A cutting tool with a defined geometry and a custom-made abrasive tool was used. The bone samples were cut in three directions, depending on the orientation of the osteons. The cutting forces, acoustic emission, and surface topography were measured. The level of isotropy and the topography of the grooves showed statistical differences relative to the anisotropy directions. After orthogonal processing, the surface topography parameter Ra was determined from 1.38 ± 0.17 μm to 2.82 ± 0.32. In the case of abrasive processing, no correlation was found between the orientation of osteons and topographical properties. The average groove density for abrasive machining was below 1004 ± 0.7, and for orthogonal, it was above 1156 ± 58. Due to the positive properties of the developed bone surface, it is advisable to cut in the transverse direction and parallel to the axis of the osteons.

Bone Abrasive Machining: Influence of Tool Geometry and Cortical Bone Anisotropic Structure on Crack Propagation

The abrasive machining of cortical tissue is used in many arthroplasties and craniofacial surgery procedures. However, this method requires further research due to the processes’ complexity and the tissue’s composite structure. Therefore, studies were carried out to assess the impact of grid geometry and the anisotropic structure of bone tissue on the cutting process and crack propagation. The analysis was performed based on an orthogonal cutting in three directions. The grain shape has been simplified, and the cutting forces, crack path and surface quality were monitored. The results indicate that a depth of cut at 100−25 µm allows the most accurate cutting control. A transverse cutting direction results in the greatest surface irregularity: Iz = 17.7%, Vvc = 3.29 mL/m2 and df = 5.22 µm and generates the most uncontrolled cracks. Maximum fracture force values of FF > 80 N were generated for d = 175 µm. For d < 5 µm, no cracks or only slight penetration occurs. A positive γ provides greater repeatability and crack control. Negative γ generates penetrating cracks and uncontrolled material damage. The individual types of cracks have a characteristic course of changes in Fx. The clearance angle did not affect the crack propagation.

Influence of Machining Parameters on Cutting and Chip-Formation Process during Cortical Bone Orthogonal Machining

Cortical bone machining is commonly used in craniofacial surgery. The shaping of bone surfaces requires a precise determination of the process’s complexity due to the cutting tool’s defined or undefined geometry. Therefore, research was carried out to assess the impact of the rake angle (γ), clearance angle and depth of cut (d) on the cortical bone machining process. Analysis was carried out based on the orthogonal cutting in three directions. The cutting tool shape was simplified, and the cutting forces and the chip-formation process were monitored. The highest values of the resultant cutting force and shear force were recorded for γ < 0. The specific cutting force decreases with the increase of d. Cutting in the transverse direction is characterized by the highest values of resultant cutting force and shear force. The coefficient of friction depends primarily on the d and takes a constant value or increases with the increase of γ. The tests showed that the chips are formed in the entire range of d ≥ 0.5 µm and create regular shapes for d ≥ 10 µm. The research novelty confirms that even negative cutting angles guarantee controlled cutting and can find wider application in surgical procedures.

Analysis of perioperative outcomes in hip resection arthroplasty

BACKGROUND

Hip resection arthroplasty (HRA) is a salvage surgical technique for the management of complex hip conditions wherein arthroplasty may be contraindicated. The purpose of this study was to review modern-day indications for HRA and compare outcomes between patients undergoing HRA and revision total hip arthroplasty (RTHA).

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) was used to identify patients undergoing HRA or RTHA between 2012 and 2017. Patient demographics, risk factors, and perioperative complications were analyzed. Multivariate regression was used to determine predictors of early postoperative complications. Propensity score matching (PSM) was performed to compare relative risks (RR) of complications in HRA compared to RTHA.

RESULTS

290 patients underwent HRA between 2012 and 2017. Infection was the most common indication for HRA (39.8%), followed by femoral neck fracture or malunion/nonunion (26%) and prosthetic instability (12.2%). Increased body mass index (BMI) (p = 0.012) and chronic obstructive pulmonary disease (COPD) (p = 0.007) were associated with increased risk of complication in HRA. There were no significant differences in short-term complication risks between RTHA and HRA.

CONCLUSIONS

HRA was associated with short-term complication rates comparable to RTHA. These findings may help in surgical decision-making and appropriate indications in the present day.

LEVEL OF EVIDENCE

III.

A 5-year follow-up of Girdlestone resection arthroplasty in hip infection continued by Total hip replacement: A case report

Introduction

Resection arthroplasty of the hip was already performed for recent 100 years. This kind of surgery has been used for a wide variety of hip problems such as infection, degenerative osteoarthritis and prosthetic joint infection. Total hip replacement is remarkable procedure in order to relieve pain and restore hip function. We present this report to describe our experience in treating hip infection by used two stages of surgery.

Case presentation

A 61-years old male suffered left hip infection that leads severe destruction on his joint. He felt badly pain on his hip with significant disability associated it such as limping, restriction of movements, and shortening of the limb. The hip movements were painful and caused walking in antalgic gait. Radiologic examination at that time revealed gross destruction of femoral head as well as acetabulum, irregular and hazy joint margins with diminished joint space. Patient was diagnosed with chronic non-specific inflammation of the hip joint.

Result

Two stages surgery were performed on this patient. Resection arthroplasty firstly performed in order to eradicate the infection completely and alleviate very bothersome pain for improvement of patient's quality of life. Two years later, after patient was ready for next stage mentally, cemented total hip replacement performed to achieve normal function of the hip. Five-years follow up functional outcome was performed. Patient was very satisfied with the result with Harris hip scores was 95.

Conclusion

Resection arthroplasty of the hip followed by a conversion to total hip replacement in hip infection case provide complete infection eradication, good functional outcome and satisfaction for the patient. Although the procedure was time-consuming it can be a choice if the eradication of infection still in a doubt.

A new technique for proximal femoral resection in non-ambulatory patients with cerebral palsy

Proximal femoral resection may be proposed to non-ambulatory patients with cerebral palsy and chronic painful hip dislocation. McCarthy's technique confers good results but does not solve the problems related to femoral reascension (bone migration causing painful osseous or cutaneous conflict). We describe a new technique of resection-interposition of the proximal end of the femur which preserves the greater trochanter by an orthogonal osteotomy below the lesser trochanter while maintaining the gluteal-vastus lateralis strut in continuity. A suture of the remaining joint capsule upon itself and a trans-trochanteric capsulodesis are associated to stabilize the cephalic displacement of the femur.

Proximal femur shaft fracture in a case of ipsilateral resection arthroplasty of a tuberculous hip - A rare case report

Femur shaft fracture is a common entity in orthopaedic practice, but how commonly does one encounter a subtrochanteric femur fracture in ipsilateral resection arthroplasty of a tuberculous hip after a decade of uneventful unassisted ambulation post resection procedure ? Till date only 2 patients have been reported worldwide with femur diaphyseal fracture with a history of ipsilateral resection arthroplasty all performed within a year of fracture occurrence. The intriguing factor of our case was the fact that post resection, patient was ambulatory for a decade and the fracture occurred at a subtrochanteric level. Thus we report a case of 35 year old male with subtrochanteric femur fracture due to minor trauma to right thigh, with a history of tuberculous arthritis of right hip for which surgical management in the form of resection arthroplasty was done 10 years back. After a thoughtful decision making and plan formulation we managed the patient with surface fixation with a pre contoured GT (greater trochanter) configuration plate after taking into consideration status of intact GT, osteoporosis, pseudoarthrosis level and post operative ambulation and rehabilitation.

Proposal for a Novel Abrasive Machining Method for Preparing the Surface of Periarticular Tissue during Orthopedic Surgery on Hip Joints

Drilling, cutting, and milling are the most common methods used in orthopedic surgery. However, popular machining methods do not obtain the complex shape of the periarticular tissue surfaces, increasing operation time and patient recovery. This paper reports an attempt to research a novel design of a machining process for surgical procedures. A device using abrasion machining based on mechanical erosion was proposed. Machining uses an undefined geometry of the cutting grains to cut tissue in any direction during oscillatory tool movement. This new concept is based on a cylindrical abrasive device made of brown fused alumina and silicon carbide grains deposited with an epoxy resin binder on the surface of a polyamide shaft. The best results in terms of machining efficiency were obtained for grains of the BFA80 type. Cutting experiments with different values in terms of cutting speed, granulation of the abrasive grains, pressure forces, and machining scope showed that the proposed concept, by developing the shape of the device, allows for penetration of the tissue structure. The research shows the possibility of using the proposed method during periarticular tissue machining.