James D. Stoney

Does Accurate Anatomical Alignment Result in Better Function and Quality of Life? Comparing Conventional and Computer-Assisted Total Knee Arthroplasty

This is a randomized prospective controlled trial comparing the alignment, function, and patient quality-of-life outcomes between patients undergoing conventional (CONV) and computer-assisted (CAS) knee arthroplasty. One hundred and fifteen patients (60 CAS, 55 CONV) underwent cemented total knee arthroplasty. Three patients were lost to follow-up. Eighty-eight percent (CAS) vs 61% (CONV) of knees achieved a mechanical axis within 3 degrees of neutral (P = .003). Aligning femoral rotation with the epicondylar axis was accurately achieved in CAS and CONV with no significant difference. Patients with coronal alignment within 3 degrees of neutral had superior International Knee Society and Short-Form 12 physical scores at 6 weeks, 3 months, 6 months, and 12 months after surgery. Computer-assisted total knee arthroplasty achieves greater accuracy in implant alignment and this correlates with better knee function and improved quality of life.

The impact of pre-operative obesity on weight change and outcome in total knee replacement: A PROSPECTIVE STUDY OF 529 CONSECUTIVE PATIENTS

We carried out a prospective, continuous study on 529 patients who underwent primary total knee replacement between January 2006 and December 2007 at a major teaching hospital. The aim was to investigate weight change and the functional and clinical outcome in non-obese and obese groups at 12 months post-operatively. The patients were grouped according to their pre-operative body mass index (BMI) as follows: non-obese (BMI < 30 kg/m(2)), obese (BMI (3) 30 to 39 kg/m(2)) and morbidly obese (BMI > 40 kg/m(2)). The clinical outcome data were available for all patients and functional outcome data for 521 (98.5%). Overall, 318 (60.1%) of the patients were obese or morbidly obese. At 12 months, a clinically significant weight loss of > or =5% had occurred in 40 (12.6%) of the obese patients, but 107 (21%) gained weight. The change in the International Knee Society score was less in obese and morbidly obese compared with non-obese patients (p = 0.016). Adverse events occurred in 30 (14.2%) of the non-obese, 59 (22.6%) of the obese and 20 (35.1%) of the morbidly obese patients (p = 0.001).

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.

Treatment of type-two odontoid fractures in halothoracic vests

We treated 22 patients with type-two odontoid fractures in halothoracic vests for six to eight weeks followed by a Philadelphia collar for four weeks. Eighteen patients were reviewed by questionnaire and radiography at a mean of 40 months after injury. We assessed union, fracture position, the degree of permanent pain and stiffness, satisfaction with the treatment and the outcome. The overall union rate was 82%. Posterior malunion with residual posterior displacement or angulation was associated with a higher incidence of persisting pain. The position at union did not correlate with the residual cervical stiffness. Fractures failed to unite in four patients (18%) none of whom had late neurological sequelae, although they had more late pain. There were associations between the development of nonunion and an extension-type injury, age over 65 years and delay in diagnosis.

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.

The need for patellar resurfacing in total knee arthroplasty: a literature review

The controversy over whether or not to routinely resurface the patella during a total knee arthroplasty has persisted despite three decades of successful joint replacement procedures. Advocates for routine patellar resurfacing admit the occasional need for secondary patellar resurfacing and declare increased incidence of anterior knee pain in patients with non‐resurfaced patellae as a cause for worry. Surgeons that leave the patella unresurfaced cite avoidance of complications that include patellar fracture, avascular necrosis, patellar tendon injury and instability. This review discusses the available literature on patellar resurfacing through an evidence‐based analysis of randomized and pseudo‐randomized controlled trials and published meta‐analyses to date. The published literature seems to favour resurfacing the patellar routinely. Selective patellar resurfacing would be the ideal solution if sound pre‐operative criteria could be established. So far, a method for accurately predicting which patients can avoid patellar resurfacing has not been found. Future research looking at patellar resurfacing should concentrate on developing criteria for selecting those patients that would benefit from patellar resurfacing and those that would do as well without resurfacing, and thus, limiting potential surgical complications.

Comparison of functional and radiological outcomes after computer-assisted versus conventional total knee arthroplasty: a matched-control retrospective study

Purpose. To compare the radiological and functional outcomes of patients who underwent either computer-assisted or conventional total knee arthroplasty (TKA). Methods. Two groups of 50 patients each underwent either computer-assisted or conventional TKA were retrospectively studied. Patients were matched according to body mass index (BMI), gender, and age. Three senior orthopaedic surgeons with comparable experience performed all surgeries, using 3 different prostheses. The surgical approach and peri- and postoperative regimens were the same. The mechanical axis and the tibial and femoral angles were measured using standardised long-leg weight-bearing radiographs. Overall function was assessed using the Short Form-12 (SF-12) and International Knee Society (IKS) scores. Results. No intra-operative technical difficulties were encountered in either group. The computer-assisted group resulted in more consistent and accurate alignments in both the coronal and sagittal planes and better SF-12 and IKS scores. In obese patients (BMI≥30 kg/m2), computer-assisted TKA provided better alignment than the conventional technique. Conclusion. Computer-assisted TKA improves implant positioning, limb alignment, and overall functional outcome. It may be particularly advantageous for obese patients.

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.