Journal of Orthopaedic Surgery and Research - Latest Articles

Biomechanical testing of implant free wedge shaped bone block fixation for bone patellar tendon bone anterior cruciate ligament reconstruction in a bovine model

Charles Willis-Owen — 2010-09-02T00:00:00Z

Background: The use of an interference fit wedged bone plug to provide fixation in the tibial tunnel when using bone-patellar tendon-bone autograft for anterior cruciate ligament reconstruction offers many theoretic advantages including the potential to offer a more economical and biological alternative to screw fixation. This technique has not been subjected to biomechanical testing. We hypothesised that a wedged bone plug fixation technique provides equivalent tensile load to failure as titanium interference screw fixation. Methods: In a controlled laboratory setting, anterior cruciate ligament reconstruction was performed in 36 bovine knees using bone-patella-bone autograft. In 20 knees tibial fixation relied upon a standard cuboid bone block and interference screw. In eight knees a wedge shaped bone block with an 11mm by 10mm base without a screw was used. In a further eight knees a similar wedge with a 13mm by 10mm base was used. Each specimen used a standard 10mm tibial tunnel. The reconstructions were tested biomechanically in a physiological environment using an Instron machine to compare ultimate failure loads and modes of failure. Results: Statistical analysis revealed no significant difference between wedge fixation and screw fixation (p=0.16), or between individual groups (interference screw versus 11 mm versus 13 mm wedge fixation) (P=0.35). Conclusions: Tibial tunnel fixation using an impacted wedge shaped bone block in anterior cruciate ligament reconstruction has comparable ultimate tensile strength to titanium interference screw fixation.

A mid term comparison of open wedge high tibial osteotomy vs unicompartmental knee arthroplasty for medial compartment osteoarthritis of the knee

Ryohei Takeuchi — 2010-08-30T00:00:00Z

Background: The choice of surgical treatments for unicompartment osteoarthritis (OA) of the knee is still somewhat controversial. Midterm results from cases treated using unicompartmental knee arthroplasty (UKA) or open wedge high tibial osteotomy (OWHTO) were evaluated retrospectively. Methods: Twenty-seven knees of 24 patients with varus deformities underwent OWHTO and 30 knees of 18 patients underwent UKA surgeries for the treatment of medial compartmental osteoarthritis (OA). The KSS score, FTA, range of motion and complications were evaluated before and after surgery. Results: The preoperative mean KSS scores were 49 points in the OWHTO group and 62 in the UKA group which improved postoperatively to 89 (excellent; 19 knees, good; 8 knees), and 88 (excellent; 25, good; 4, fair; 1), respectively. There was no significant difference between the OWHTO and UKA scores. Thirteen patients in the OWHTO group could sit comfortably in the formal Japanese style after surgery. The preoperative mean FTA values for the OWHTO and UKA groups were 182 degrees and 184, and at follow-up measured 169 and 170, respectively. In the UKA group, the femoral component and the polyethylene insertion in one patient was exchanged at 5 years post-surgery and revision TKAs were performed in 2 cases. In the OWHTO group, one tibial plateau fracture and one subcutaneous tissue infection were noted. Conclusions: Treatment options should be carefully considered for each OA patient in accordance with their activity levels, grade of advanced OA, age, and range of motion of the knee. OWHTO shows an improved indication for active patients with a good range of motion of the knee.

Lessons to be learned from a missed case of Hamate fracture: a case report

Vishal Borse — 2010-08-27T00:00:00Z

IntroductionWe report the case of a missed fracture through the body of the hamate bone, only detected on a later, mistakenly taken 30o oblique x-ray view. This case highlights some of the problems encountered with traditional x-ray views, and the need to consider oblique views as either standard procedure or as an adjunct where clinical suspicion remains high even in the presence of normal x-rays.Case presentationA healthy 26-year-old Caucasian male fell whilst jogging, suffering a low velocity injury to his right hand. Initial accident and emergency examination and x-rays failed to demonstrate a fracture. At clinic, anteroposterior and carpal tunnel radiographs showed no fracture, however a mistakenly taken oblique x-ray revealed a displaced hamate body fracture. Conclusion: The authors believe that where a hamate fracture is suspected, an oblique x-ray view should be considered as part of the initial diagnostic investigations. Furthermore an oblique x-ray view is of particular use when clinical suspicion for hamate fracture remains high in the light of otherwise normal x-rays.

Tuberculosis of symphysis pubis in a 17 year old male : a rare case presentation and review of literature

Kamal Bali — 2010-08-27T00:00:00Z

Tuberculosis of symphysis pubis is a rare condition with hardly any report of such cases in the last decade. It is necessary to distinguish the entity from more common ones like Osteitis pubis and Osteomyelitis of pubis symphysis by urgent means in order to start the treatment early and thereby minimize morbidity and prevent complications. A rare case of tuberculosis of symphysis pubis in a 17 year old male is described. A high index of suspicion along with an extensive workup including 3-phase bone scan and fine needle aspiration led to the diagnosis. The patient had an excellent outcome following a complete course of multidrug chemotherapy for tuberculosis.

Medial pelvic migration of the lag screw in a short gamma nail after hip fracture fixation: a case report and review of the literature

Xinning Li — 2010-08-27T00:00:00Z

Hip fractures are a common injury among the elderly. Internal fixation with an intramedullary (IM) system has gained popularity for the treatment of intertrochanteric femur fractures. Multiple complications associated with IM fracture fixation have been described, however, we report a rare complication of medial pelvic migration of the lag screw of a short IM nail in a stable construct ten weeks post surgery. The patient was subsequently treated with Lag Screw removal and revision surgery with a shorter Lag Screw and an accessory cannulated screw acting as a de-rotational device. The patient did well with the revision surgery and was able to return to full activities.

Treatment of refractory hip pain with sodium hyaluronate (Hyalgan) in a patient with the Marshall-Smith Syndrome: A case report

Matthew Salter — 2010-08-23T00:00:00Z

The Marshall Smith Syndrome (MSS) is a rare congenital disorder, displaying a constellation of unique symptoms, including orofacial dysmorphisms, accelerated osseous maturation and dysplasias, mental retardation, and respiratory maladies. Few individuals with MSS survive past early childhood. In this case report, we describe a unique treatment for a 30 year-old patient with MSS who presented to our pain medicine clinic for management of pain secondary to uncontrolled bilateral hip dysplasias.

Displaced proximal humeral fractures: an Indian experience with locking plates

Sameer Aggarwal — 2010-08-23T00:00:00Z

Background: The treatment of displaced proximal humerus fractures, especially in elderly, remains controversial. The objective of this study was to evaluate functional outcome of locking plate used for fixation of these fractures after open reduction. We also attempted to evaluate the complications and predictors of loss of fixation for such an implant. Methods: Over two and a half years, 56 patients with an acute proximal humerus fracture were managed with locking plate osteosynthesis. 47 of these patients who completed a minimum follow up of 1 year were evaluated using Constant score calculation. Statistical analysis was done using SPSS 16 and a p value of less than 0.05 was taken as statistically significant. Results: The average follow up period was around 21.5 months. Outcomes were excellent in 17%, good in 38.5%, moderate in 34% while poor in 10.5%. The Constant score was poorer for AO-OTA type 3 fractures as compared to other types. The scores were also inferior for older patients (> 65 years old). Complications included screw perforation of head, AVN, subacromial impingement, loss of fixation, axillary nerve palsy and infection. A varus malalignment was found to be a strong predictor of loss of fixation. Conclusion: Locking plate osteosynthesis leads to satisfactory functional outcomes in all the patients. Results are better than non locking plates in osteoporotic fractures of the elderly. However the surgery has steep learning curve and various complications could be associated with its use. Nevertheless we believe that a strict adherence to the principles of locking plate use can ensure good result in such challenging fractures.

Biology and augmentation of tendon-bone insertion repair

Ppy Lui — 2010-08-21T00:00:00Z

Surgical reattachment of tendon and bone such as in rotator cuff repair, patellar-patella tendon repair and anterior cruciate ligament (ACL) reconstruction often fails due to the failure of regeneration of the specialized tissue ("enthesis") which connects tendon to bone. Tendon-to-bone healing taking place between inhomogenous tissues is a slow process compared to healing within homogenous tissue, such as tendon to tendon or bone to bone healing. Therefore special attention must be paid to augment tendon to bone insertion (TBI) healing. Apart from surgical fixation, biological and biophysical interventions have been studied aiming at regeneration of TBI healing complex, especially the regeneration of interpositioned fibrocartilage and new bone at the healing junction. This paper described the biology and the factors influencing TBI healing using patella-patellar tendon (PPT) healing and tendon graft to bone tunnel healing in ACL reconstruction as examples. Recent development in the improvement of TBI healing and directions for future studies were also reviewed and discussed.

Assessing mechanical integrity of spinal fusion by in situ endochondral osteoinduction in the murine model

Ashvin Dewan — 2010-08-21T00:00:00Z

Background: Historically, radiographs, micro-computed tomography (micro-CT) exams, palpation and histology have been used to assess fusions in a mouse spine. The objective of this study was to develop a faster, cheaper, reproducible test to directly quantify the mechanical integrity of spinal fusions in mice. Methods: Fusions were induced in ten mice spine using a previously described technique of in situ endochondral ossification, harvested with soft tissue, and cast in radiolucent alginate material for handling. Using a validated software package and a customized mechanical apparatus that flexed and extended the spinal column, the amount of intervertebral motion between adjacent vertebral discs was determined with static flexed and extended lateral spine radiographs. Micro-CT images of the same were also blindly reviewed for fusion. Results: Mean intervertebral motion between control, non-fused, spinal vertebral discs was 6.1+/-0.2 degrees during spine flexion/extension. In fusion samples, adjacent vertebrae with less than 3.5 degrees intervertebral motion had fusions documented by micro-CT inspection. Conclusions: Measuring the amount of intervertebral rotation between vertebrae during spine flexion/extension is a relatively simple, cheap (<$100), clinically relevant, and fast test for assessing the mechanical success of spinal fusion in mice that compared favorably to the standard, micro-CT.

An in vivo evaluation of bone response to three implant surfaces using a rabbit intramedullary rod model

Juan Hermida — 2010-08-16T00:00:00Z

Our study was designed to evaluate osseointegration among implants with three surface treatments: plasma-sprayed titanium (P), plasma-sprayed titanium with hydroxyapatite (PHA), and chemical-textured titanium with hydroxyapatite (CHA). Average surface roughness (Ra) was 27 microns for the P group, 17 microns for the PHA group, and 26 microns for the CHA group. Bilateral distal intramedullary implants were placed in the femora of thirty rabbits. Histomorphometry of scanning electron microscopy images was used to analyze the amount of bone around the implants at 6 and 12 weeks after implantation. Greater amounts of osseointegration were observed in the hydroxyapatite-coated groups than in the noncoated group. For all implant surfaces, osseointegration was greater at the diaphyseal level compared to the metaphyseal level. No significant differences were seen in osseointegration between the 6 and 12 week time points. Although the average surface roughness of the P and the CHA groups was similar, osseointegration of the CHA implants was significantly greater. The results of this in vivo lapine study suggest that the presence of an hydroxyapatite coating enhances osseointegration despite similarities in average surface roughness.