Equivalent results of medial and lateral parapatellar approach for total knee arthroplasty in mild valgus deformities.

PURPOSE: When performing total knee arthroplasty (TKA) in valgus knee deformities, a medial or lateral parapatellar approach can be performed, but the lateral approach is often considered technically more difficult. The purpose of this study was to compare intra-operative, early clinical and radiological outcomes of medial and lateral parapatellar approaches for TKA in the setting of moderate knee valgus (<10°). METHODS: We prospectively analysed 424 knees with pre-operative valgus deformity between 3° and 10° that underwent TKA over an 18-year period; 109 were treated with a medial approach and 315 with a lateral approach. Intra- and post-operative outcomes and complication rates after a minimum follow-up of one year were compared. RESULTS: Tourniquet (p = 0.25) and surgical (p = 0.62) time were similar between groups. The popliteus tendon was released more frequently in the medial-approach group (p = 0.04), while the iliotibial band was released more frequently in the lateral-approach group (p < 0.001). A tibial tuberosity osteotomy was performed more frequently in the lateral- than medial-approach group (p = 0.003). No significant differences in limb alignment (p = 0.78), or Knee Society Score (KSS) knee (p = 0.32) and function (p = 0.47) results were noted based on surgical approach, and complication rates were similar between groups (p = 0.53). CONCLUSIONS: Lateral parapatellar approach is a safe and effective surgical technique for performing TKA in moderately valgus knees. These equivalent early results are encouraging for systematic use of the lateral approach in moderately valgus knees.

Factors influencing posterior tibial slope and tibial rotation in opening wedge high tibial osteotomy.

PURPOSE: Opening wedge high tibial osteotomy (HTO) is an accepted treatment option for medial compartment knee osteoarthritis with associated varus lower limb axis in younger, more active patients. A concern with the use of this technique is that posterior tibial slope (PTS) and tibial rotation can be altered. We hypothesized that there is a tendency to increase the PTS and internal rotation of the distal tibia during the procedure and that certain intra-operative parameters may influence the amount of change that can be expected. METHODS: A cadaveric model and surgical navigation system were used to evaluate the influence of certain intra-operative factors of the degree of PTS and tibial rotation change observed during medial opening HTO. Parameters evaluated included: degree of osteotomy opening, knee flexion angle, location of limb support (thigh versus foot), performance of a posteromedial release, the status of the lateral cortical hinge, and the degree of osteoarthritis present in the knee. RESULTS: Combining measurements of all specimens and parameters, a mean PTS increase of 2.7° ± 3.9° and a mean tibial internal rotation of 1.5° ± 2.9° were observed. Clinically, significant changes in tibial slope (>2°) occurred in 50.4 % of corrections, while significant changes in tibial rotation (>5°) occurred in only 11.9 % of corrections. Patients with significant osteoarthritis and concomitant flexion contracture, cases where large corrections were required, and procedures in which the lateral cortical hinge was disrupted were associated with increased PTS change. The other factors evaluated did not exert a significant influence of the degree of PTS change observed. CONCLUSIONS: Surgeons should be vigilant for possible PTS change, particularly in high-risk situations as outlined above. Routine use of an intra-operative measure of PTS is recommended to avoid inadvertent slope change.

Results and complications of single-stage total knee arthroplasty and high tibial osteotomy.

PURPOSE: Long-term survival in total knee arthroplasty (TKA) depends on multiple factors, including restoration of mechanical alignment and obtaining optimal ligament balance. The aim of this study was to document the results of single-stage TKA combined with high tibial osteotomy for managing femorotibial arthrosis with significant frontal-plane deformity. METHODS: Patients with osteoarthritis of the knee and extra-articular deformity in > 10° and operated between 1997 and 2001 were reviewed retrospectively. In each case, a high tibial osteotomy combined with a posterior stabilised TKA was performed. Patients were assessed using the Knee Society Score (KSS). The femorotibial mechanical angle was measured on radiographs pre- and postoperatively and at the most recent follow-up. RESULTS: Fifteen knees in 12 patients were included in the study. Mean age was 68.2; average follow-up was 78 months (22.1-145.9). The KSS improved significantly from 47.1 (28-58) to 60.7 (40-94) points (p < 0.05), with the KSS functional score improving from 45.1 (21-69) to 72.3 (30-100) points (p < 0.05). The femorotibial mechanical axis (mFTA) also improved significantly, from 161.7° (156-170°) preoperatively to 175.8° (170-182°) postoperatively (p = 0.002). There were four intra-operative tibial plateau fractures and two revisions for nonunion at the osteotomy site. Survival at 22 months was 86.7% [95% confidence interval (CI) 64.5-99.5%]. CONCLUSIONS: The combination of a TKA and high tibial osteotomy is a valid option for treating arthrosis with large extra-articular frontal-plane deformity. Rigid fixation of the osteotomy is essential.

Total knee arthroplasty of the stiff knee: three hundred and four cases.

PURPOSE: The purpose of this study was to analyse the results of total knee arthroplasty (TKA) in stiff knees (flexion ≤90° and/or flexion contracture ≥20°). Our hypothesis was that despite having poorer results than those obtained in a "standard" population and a high rate of complications, TKA was a satisfactory treatment in patients with osteoarthritis of the knee associated with significant stiffness. METHODS: Three hundred and four consecutive primary HLS TKAs (Tornier), whose data were prospectively collected between October 1987 and October 2012, were retrospectively analysed at a mean of 60 months (range, 12-239) postoperatively. Two groups, those with a "flexion contracture" and those with a "flexion deficit", were assessed for postoperative range of motion (as integrated to the Knee Society score [KSS]), physical activity level and patient satisfaction. RESULTS: At the latest follow-up, range of motion was significantly improved, as was the KSS. Ninety-four percent of patients were satisfied or very satisfied, and activity levels were increased after surgery. The complication rate, however, was high in patients with a preoperative flexion deficit (17%). Pain and residual stiffness were the most common complications. CONCLUSION: TKA provides satisfactory results in patients with knee osteoarthritis associated with significant pre-operative stiffness. The surgical plan should be adapted to anticipate complications, which are particularly frequent in the presence of a flexion deficit.

The concept of double bundle ACL simulation with a single bundle patellar tendon graft. A cadaveric feasibility study.

BACKGROUND: There is significant interest in the restoration of the double-bundle anatomy of the native ACL when performing ACL reconstruction. Possible techniques include those utilizing two separate grafts with independent tunnels and those that attempt to mimic this anatomy with a single graft and fewer tunnels. Many of the latter techniques require specific instrumentation and are technically challenging. We demonstrate that the double-bundle anatomy of the native ACL can theoretically be mimicked by a single-bundle reconstruction. METHODS: We performed single bundle ACL reconstruction with a bone-patellar tendon-bone (BTB) graft in two cadaveric knees. Both grafts were placed to mimic the native ACL footprints - one reconstruction was performed with rectangular bone blocks and oval tunnels and one was performed utilizing a standard BTB graft and round tunnels. Qualitative assessment of graft behavior was made as the knees were taken through a range of motion. RESULTS: The ACL graft was able to qualitatively mimic the behavior of the native ACL in both knees provided the bone blocks were correctly orientated. CONCLUSIONS: ACL reconstruction with a single BTB graft can qualitatively mimic the behavior of the two bundles of the native ACL. The key to ensuring this behavior was noted to be appropriate orientation of the graft in the tunnels. Quantitative biomechanical investigations are necessary to evaluate the impact of graft orientation on function.

MACI - a new era?

Full thickness articular cartilage defects have limited regenerative potential and are a significant source of pain and loss of knee function. Numerous treatment options exist, each with their own advantages and drawbacks. The goal of this review is to provide an overview of the problem of cartilage injury, a brief description of current treatment options and outcomes, and a discussion of the current principles and technique of Matrix-induced Autologous Chondrocyte Implantation (MACI). While early results of MACI have been promising, there is currently insufficient comparative and long-term outcome data to demonstrate superiority of this technique over other methods for cartilage repair.