Sina Babazadeh

Coronal alignment correlates with outcome after total knee arthroplasty: five-year follow-up of a randomized controlled trial.

In a prospective randomized control trial comparing computer-assisted vs conventional total knee arthroplasty, we previously reported that patients with coronal alignment within 3° of neutral had superior international knee society and Short-Form 12 (SF-12) physical scores at 6 weeks, 3 months, 6 months, and 12 months after surgery. Computer-assisted total knee arthroplasty achieved greater accuracy in implant alignment, and this correlated with better knee function and quality of life. At 5 years, 90 of 111 patients assessed in our original study were reviewed. Coronal alignment within 3° of neutral continued to be correlated with superior International Knee Society and SF-12 scores. Coronal alignment greater than 3° was associated with a significant decline in SF-12 mental health scores.

The long leg radiograph is a reliable method of assessing alignment when compared to computer-assisted navigation and computer tomography

BACKGROUND The mechanical alignment of the knee is an important factor in planning for, and subsequently assessing the success of a knee replacement. It is most commonly measured using a long-leg anteroposterior radiograph (LLR) encompassing the hip, knee and ankle. Other modalities of measuring alignment include computer tomography (CT) and intra-operative computer navigation (Cas). Recent studies comparing LLRs to Cas in measuring alignment have shown significant differences between the two and have hypothesized that Cas is a more accurate modality. This study aims to investigate the accuracy of the above mentioned modalities. METHODOLOGY A prospective study was undertaken comparing alignment as measured by long-leg radiographs and computer tomography to intra-operative navigation measurements in 40 patients undergoing a primary total knee replacement to test this hypothesis. Alignment was measured three times by three observers. Intra- and inter-observer correlation was sought between modalities. RESULTS Intra-observer correlation was excellent in all cases (>0.98) with a coefficient of repeatability <1.1°. Inter-observer correlation was also excellent measuring >0.960 using LLRs and >0.970 using CT with coefficient of repeatability <2.8°. Inter-modality correlation proved to be higher when comparing LLRs and CT (>0.893), than when comparing either of these modalities with Cas (>0.643 and >0.671 respectively). Pre-operative values had the greatest variability. CONCLUSION Given its availability and reduced radiation dose when compared to CT, LLRs should remain the mainstay of measuring the mechanical alignment of the lower limb, especially post-operatively. LEVEL OF EVIDENCE II.

Joint line position correlates with function after primary total knee replacement: A RANDOMISED CONTROLLED TRIAL COMPARING CONVENTIONAL AND COMPUTER-ASSISTED SURGERY

The role of computer-assisted surgery in maintaining the level of the joint in primary knee joint replacement (TKR) has not been well defined. We undertook a blinded randomised controlled trial comparing joint-line maintenance, functional outcomes, and quality-of-life outcomes between patients undergoing computer-assisted and conventional TKR. A total of 115 patients were randomised (computer-assisted, n = 55; conventional, n = 60). Two years post-operatively no significant correlation was found between computer-assisted and conventional surgery in terms of maintaining the joint line. Those TKRs where the joint line was depressed post-operatively improved the least in terms of functional scores. No difference was detected in terms of quality-of-life outcomes. Change in joint line was found to be related to change in alignment. Change in alignment significantly affects change in joint line and functional scores.

The relevance of ligament balancing in total knee arthroplasty: how important is it? A systematic review of the literature

Ligament balancing affects many of the postoperative criteria for a successful knee replacement. A balanced knee contributes to improved alignment and stability. Ligament balancing helps reduce wear and loosening of the joint. A patient with a balanced knee is more likely to have increased range of motion and proprioception, and decreased pain. All these factors help minimize the need for revision surgery. Complications associated with ligament balancing can include instability caused by over-balancing and the possibility of neurovascular damage during or as a result of ligament balancing. This article attempts to summarize the literature, to define a balanced knee, and outline the benefits and possible complications of ligament balancing. Different techniques, sequences, and tools used in ligament balancing, and their relevance in correcting various deformities are reviewed.

Gap balancing sacrifices joint-line maintenance to improve gap symmetry: a randomized controlled trial comparing gap balancing and measured resection.

A total knee arthroplasty can be completed using two techniques; measured resection or gap balancing. A prospective blinded randomized controlled trial was completed with 103 patients randomized to measured resection (n = 52) or gap balancing (n = 51). Primary outcome measure was femoral component rotation. Secondary outcome measures were joint-line change, gap symmetry and function and quality-of-life outcomes. Gap balancing resulted in a significantly raised joint-line compared to measured resection. Gap symmetry was significantly better using gap balancing. Functional outcomes and quality-of-life were not significantly different at 24 months. Using computer navigation, gap balancing significantly raises the joint-line in order to improve gap symmetry. This does not result in a clinical difference in function or quality of life at 24 months.

An interesting diagnosis for a presacral mass: case report.

A presacral mass can present a diagnostic dilemma for the surgical oncologist. Differential diagnoses include congenital causes such as teratoma or chordoma, neurological causes such as neurilemoma or neurofibroma or other malignancies such as lymphoma or sarcoma. Diagnosis usually requires imaging such as CT and MRI and tissue biopsy. We present an unusual cause of a presacral mass being extramedullary haematopoiesis, found incidentally in a 71 year old female. Extramedullary haematopoiesis is defined as the production of myeloid and erythroid elements outside of the bone-marrow. This diagnosis is extremely rare in the presacral area especially in a patient with no haematological abnormalities. A review of the literature is presented.

Significance of sentinel infective events in haematogenous prosthetic knee infections.

Background:  Infection after primary knee arthroplasty is devastating. The aim of this study was to determine the significance of sentinel infective events prior to the development of haematogenous prosthetic knee infection.

Arthroplasty of a Charcot knee

The Charcot knee - or neuropathic arthropathy - presents a considerable challenge to the orthopaedic surgeon. Caused by a combination of sensory, motor and autonomic neuropathy, it was originally described as an arthritic sequelae of neurosyphilis. In todays western orthopaedics it is more often caused by diabetes. A Charcot knee is often symptomatically painful and unstable. Traditional management has usually been conservative or arthrodesis, with limited success. Arthroplasty of a Charcot joint has commonly been avoided at all costs. However, in the right patient, using the right technique, arthroplasty can significantly improve the symptoms of a Charcot joint. This article explores the evidence surrounding the role of arthroplasty in the management of a Charcot knee. Arthroplasty is compared to other forms of treatment and specific patient demographics and surgical techniques are explored in an attempt to define the role of arthroplasty in the management of a Charcot knee.

Hallux IP arthritis after MP arthrodesis managed with interpositional arthroplasty of MP joint and IP fusion: case report.

Level of Evidence: V, Expert Opinion

Atraumatic bilateral femoral neck fractures during pregnancy: a missed diagnosis.

Case report A 37-year-old primigravid woman presented with bilateral anterior groin pain. The pain began spontaneously during the third trimester and became progressively worse, causing difficulty with walking. The most likely cause of her pain was thought to be pelvic instability, and conservative management was followed. No imaging studies were performed. Anterior pelvic pain continued unabated after a caesarean delivery at 38 weeks gestation. Plain radiographs were obtained four months after delivery and revealed bilateral displaced subcapital femoral neck fractures. CT scans showed well-corticated fractures on a background of osteopenia. The subcapital fracture on the right had united in a varus position. The fracture on the left was displaced with an 11-mm gap between fracture fragments. The femoral head was eroded, precluding open reduction and internal fixation. MRI of the pelvis showed increased signal on the short TI inversion recovery (STIR) image at the fracture sites, extending into the shafts of the proximal femora (Fig. 1). These findings most likely related to transient osteoporosis of pregnancy (TOP). Endocrinology review did not reveal a secondary cause for osteoporosis. Dual-energy X-ray absorptiometry later established a diagnosis of TOP with a z-score of )2.5. The delayed diagnosis of a displaced subcapital neck of femur fracture, on the left in this woman, necessitated treatment by total hip arthroplasty (Fig. 2). The impacted subcapital fracture on the right side was managed conservatively; however, this has left her with a short right lower limb. A corrective valgus osteotomy for the right hip is being considered as a future option to restore leg length.