Correlation between the distal anterior femoral cortical axis and femoral rotational alignment: an anatomic study.

PURPOSE: To determine the correlation between the distal anterior femoral cortical axis (DAFCA) and the femoral rotational alignment/axis. METHODS: Magnetic resonance images (MRI) of 82 knees in 34 men and 23 women aged 16 to 47 (mean, 33.4) years were reviewed by a musculoskeletal radiologist. Their diagnoses included meniscal tear (n=4), chondromalacia (n=25), anterior cruciate ligament tears (n=11), and normal (n=42). In all patients the collateral ligaments were intact. The transepicondylar axis (TEA), posterior condylar axis (PCA), Whiteside line (WL), and joint line were drawn on the images, and the condylar twist angle (CTA), TEA-WL angle, DAFCA, epicondylar cortical angle (ECA), and condylar cortical angle (CCA) were measured. The correlations among ECA, CCA, and CTA (control) were assessed. RESULTS: The mean distances between the joint line and the TEA, PCA, and DAFCA were 30.8, 22.1, and 62.2 mm, respectively. The angles subtended by the intersection between the standard axes (TEA, PCA, and WL) and the DAFCA were determined. There was correlation between the CTA and ECA (r=0.34, p<0.05), between the ECA and the CCA (r=0.80, p<0.0001), and between the CTA and the CCA (r=- 0.19, p=0.08). CONCLUSION: There was correlation between the DAFCA and TEA and PCA; DAFCA can be used to determine the femoral rotational alignment when the standard landmarks are distorted by severe soft tissue and bone loss.

Risk factors for early implant-related surgical site infection.

PURPOSE: To identify the risk factors and microbes associated with early implant-related surgical site infection (SSI). METHODS: Records of 193 implant-related SSIs secondary to primary orthopaedic surgery were reviewed. Early and late SSI was defined as infection diagnosed within and after 3 months of surgery, respectively. RESULTS: Of the 193 implant-related SSIs, 29 were superficial incisional, 127 were deep incisional, and 37 were organ/space-related. 144 (90%) out of 160 SSIs used cefazolin in their prophylactic antibiotic regimen. In univariate analysis, early SSI was associated with diabetes mellitus, American Society of Anesthesiologists (ASA) score of >2, emergency procedures, and lack of antibiotic prophylaxis. In multivariable analysis, early SSI was associated with an ASA score of >2 (p=0.016). CONCLUSION: It is important to cross-check ASA score with co-morbidities to reduce early SSIs. Peri-operative optimisation and antibiotic prophylaxis should be administered prior to surgery. Appropriate modification of antibiotic prophylaxis should be considered.

Use of tantalum cones in primary arthroplasty of acute proximal tibial fractures.

Metaphyseal tantalum cones in primary total knee arthroplasty and their functional outcome is described using 3 case reports over 6 years. 3 knees in 3 elderly individuals (mean age of 70.4 years), with pre-existing osteoarthritis and complex proximal tibial fractures, were operated on. Ambulation with walking frame was achieved from post-operation day 1, with weight-bearing as tolerated. Mean range of motion was 122° and Mean Knee Society Score was 88. All showed improvement in pre-operative limb alignment. Radiological fracture union was achieved on an average of 3 months. All were independent ambulators and pain-free at the latest follow-up. Our case series shows that tantalum cones are associated with significant improvements in clinical scores, patient symptoms, range of movement, early weight-bearing and low rates of complications in complex proximal tibial fractures with poor bone stock.

Synovial Cyst: A Culprit for Recalcitrant Iliotibial Band Syndrome: A Case Report.

We present the case of a 56-year old gentleman who presented with recalcitrant iliotibial band (ITB) friction syndrome which did not improve with various modalities of conservative treatment. Magnetic Resonance Imaging (MRI) of the affected knee did not show pathology typical of ITB friction syndrome. However, open exploration revealed a synovial cyst deep to the iliotibial band, abutting against the anterolateral capsule. The presence of distinctive clinical signs on physical examination should alert clinicians to consider knee synovial cyst as a differential diagnosis when dealing with recalcitrant ITB syndrome.

Painful pretibial pseudocyst at bioabsorbable interference screw aperture two years after anterior cruciate ligament reconstruction.

We report the case of a patient with a painful subcutaneous nodule, measuring 13 mm × 17 mm, at the pretibial graft aperture site, which presented two years after a successful anterior cruciate ligament reconstruction with an autologous hamstring graft. A bioabsorbable poly-L-lactide interference screw was used for graft fixation at the tibial aperture. The patient underwent surgical excision of the lesion and curettage at the tunnel aperture. Grossly, extruded fragments of the screw and a thick pseudocapsule of surrounding tissue were excised. There was no communication between the tunnel aperture and the knee joint. The graft was also intact. Histological analysis revealed fragments of the bioabsorbable material in association with fibrous and granulomatous chronic inflammatory cells. This was consistent with a foreign body reaction. The patient subsequently recovered and resumed preinjury level of activity. To the best of our knowledge, this is the first report describing a nodular granulomatous type reaction to foreign bioabsorbable poly-L-lactide screw material subsequent to an anterior cruciate reconstruction surgery.

Role of navigated total knee arthroplasty for acute tibial fractures in the elderly.

PURPOSE: The role of total knee arthroplasty (TKA) in acute tibial fractures with existing comminution/bone loss, osteoporosis or preexistent arthritis has been described in the literature. Many of these procedures necessitate the use of stems to off-load the component and augments/wedges to avoid overresection and hence restore the joint line. Conventional methods may not be consistently accurate in restoring the desired alignment within 3° of the anatomical axis in this complex scenario. Computer-assisted TKA has been demonstrated to reproducibly and accurately restore the mechanical axis and joint line in primary TKA. Literature review has sparse data on use of navigation in acute TKA. METHODS: 9 cases of acute tibial fractures (6 tibial plateau and 3 diaphyseal) were treated by navigated primary knee arthroplasty and followed up over 26-month duration. RESULTS: All fractures healed without notable complications. Mean range of movement was 114°. Mean Knee Society score was 84. Out of 9 cases 5 were graded as excellent, 3 good and 1 fair. All knees were corrected to within a mean of 1.7° of the calculated mechanical axis. CONCLUSION: Total knee arthroplasty should be considered a treatment option for acute upper tibial fractures in the elderly with coexistent knee arthritis and poor bone stock. Computer-assisted navigation aids in restoration of mechanical axis and component positioning.

Management of knee osteoarthritis presenting with tibial stress fractures.

Stress fractures of the tibia secondary to tibial deformities from osteoarthritis are rare, and may be difficult to manage. We treated two patients with stress fractures of the proximal tibial diaphyses over a period of two years. Both patients had osteoarthritis of the knee; one with genu valgus deformity and the other, genu varus deformity. The former patient also had a distal tibial fracture and had previously undergone open reduction and internal fixation. The stress fractures of both the patients had been treated conservatively by nonoperative means, but their fractures failed to unite. They then underwent a modular total knee prosthesis with a long tibial stem extension, and subsequently, their fractures united. Both patients recovered uneventfully.

Operative fixation of a subtrochanteric fracture in a patient with previous spontaneous hip fusion.

Patients with a fused hip can present with various clinical problems, such as contralateral hip arthritis, ipsilateral knee arthritis and degenerative disc disease. There are significant deforming forces at the proximal femur in patients with a fused hip who have ipsilateral subtrochanteric fractures. We report a 66-year-old patient with a spontaneously fused right hip, who sustained an ipsilateral comminuted proximal femoral fracture secondary to a road traffic accident. Optimal operative fixation of this patient posed as a surgical challenge. We discuss the management options in this paper. Intramedullary nailing was used so as to minimise the blood loss and because of its favourable biomechanical characteristics. The patient had postoperative femoral nerve neuropraxia that eventually resolved. In patients with a fused hip who have ipsilateral subtrochanteric fractures, retrograde nailing of such fractures can serve as an optimal treatment option. However, femoral nerve palsy can be a potential complication.

Management of gamma nail breakage with bipolar hemi-arthroplasty.

Gamma nail breakage is an uncommon occurrence that often arises from fatigue failure of the implant, with a reported incidence ranging from 0.2 to 5.7 percent. We report a 73-year-old woman with a three-part intertrochanteric fracture and who presented two years postoperatively with gamma nail failure secondary to fracture non-union. This patient underwent a revision long-stem bipolar hemi-arthroplasty and has been followed-up for 24 months, with good functional and radiological results.

The epidemiology and surgical outcomes of patients undergoing primary total hip replacement: an Asian perspective.

INTRODUCTION: The number of total knee replacements far exceeds the number of primary total hip replacements (THR) in Singapore. There is a paucity of data regarding patients who undergo THR in Singapore. This paper aimed to study the epidemiology and early postoperative outcomes of patients receiving primary THR in a single tertiary institution. METHODS: This is a retrospective study of all patients undergoing primary THR between January 2003 and December 2005. The following variables were analysed: patient demographics, surgical approach, mode of implant fixation, postoperative complications and functional outcomes using D'Aubigne and Postel scoring. RESULTS: There were a total of 115 patients who underwent primary THR over a 36-month period. The mean age of patients was 55 (range 23-80) years. The male-to-female ratio was 1:2. The most common diagnoses in descending order were as follows: inflammatory arthritis, osteoarthritis, avascular necrosis, hip dysplasia and post-traumatic osteoarthritis. Patients were evaluated at a mean follow-up of 41 months, with 90.8 percent having excellent and good outcomes. There were no statistical differences between the surgical approach and implant fixation with regard to postoperative outcome. CONCLUSION: In Asian patients, the three commonest aetiologies for degenerative hip arthritis were inflammatory arthropathies, primary osteoarthritis and avascular necrosis. Regardless of diagnosis, the patient groups had comparable functional outcomes following THR.

A review of clinical pathway data of 1,663 total knee arthroplasties in a tertiary institution in Singapore.

INTRODUCTION AND OBJECTIVES: A total knee arthroplasty (TKA) clinical pathway database has been used in our institution since the year 2000. The primary aim of this study was to review the patient epidemiology, postoperative complications and factors influencing hospital length of stay following TKA. The clinical outcomes and cost-savings between elective and same day admissions for TKA patients were also reviewed. MATERIALS AND METHODS: The study cohort retrieved from the database comprised 1,371 patients (1,663 knees) who underwent total knee replacement over a 6-year time period. The following variables were reviewed: epidemiological data, admission data (elective admission [EA] versus same day admission [SDA]), hospital length of stay (LOS), and complication rates. RESULTS: The mean age of patients undergoing TKA is 65.2 years (range, 22 to 90). Osteoarthritis was the main surgical indication in 96% of the study cohort. Overall, there was a gradual decline in the hospital length of stay for the study cohort for the 6-year time period. The overall complication rate was 2% and the 3 most common complications were deep vein thrombosis, pulmonary embolism and urinary tract infection. CONCLUSION: With an increasing elderly population there will be an annual increase in the number of TKAs. In our local population TKAs are performed primarily for the Chinese female in the 7th decade. The overall complication rate of TKA remains low with a mortality rate of <1%.

Persistent knee instability following revision total knee arthroplasty.

Instability is an important cause of failure following total knee arthroplasty (TKA). Knee stability needs to be optimal in both the coronal and sagittal planes. We describe failed revision TKA with persistent deformity and instability secondary to a deficient medial collateral ligament in a 71-year-old Chinese woman. Revision knee arthroplasty using constrained implants was performed on her with good result. During both primary and revision TKA, assessment of knee stability is critical. Constrained prosthesis would need to be considered when there is significant ligamentous deficiency.

Technical challenges of advanced hip osteonecrosis managed using a vascularised fibular graft.

Management of hip osteonecrosis in the young is challenging, and femoral head preservation surgery is often preferred. We report the first local case of treating advanced hip osteonecrosis with a vascularised fibular graft in a 26-year-old man who presented with left hip pain after a fall. He was diagnosed with left hip osteonecrosis and underwent core decompression and insertion of a vascularised fibular graft. Postoperative radiographs and computed tomography of the hip were performed to assess viability of the graft. In this report, we discuss the technical considerations when operating on Asian patients and how technical difficulties are circumvented. We also report the postoperative outcome and discuss the various methods for monitoring viability of the graft.

Topical negative pressure in the treatment of infected wounds with exposed orthopaedic implants.

The use of TNP on infected open wounds with exposed orthopaedic implants has not yet been described in the literature. Here, its application on these wounds accelerated healing and enabled definitive wound closure to be undertaken.

Management of extensor mechanism disruptions occurring after total knee arthroplasty.

Extensor mechanism disruption from quadriceps tendon rupture, patellar fracture, or patellar tendon rupture is an uncommon complication of total knee arthroplasty. Extensor mechanism disruption can occur either intraoperatively or postoperatively. Common intraoperative causes include avulsion or tendon injury arising from excessive tension during surgical exposure, improper patellar resection, and devascularization due to injudicious lateral retinacular release or multiple prior surgeries. The usual postoperative causes are tissue necrosis arising from infection, component malalignment, and trauma. A wide range of treatment options is available for managing these difficult problems, and recent advances in alternative techniques for reconstruction have yielded promising results.