Purpose: Medial opening wedge high tibial osteotomy (MOW-HTO) is a well-described operative method for the treatment of medial gonarthrosis in selected patients. One of the concerns with MOW-HTO is the potential delayed or nonunion across the medial gap. Traditionally, this gap was filled with autograft to facilitate union. Although alternative graft options, such as allograft, are available and have theoretical advantages over autograft, little is known about their efficacy relative to autograft in MOW-HTO. The purpose of our study was to perform a retrospective matched cohort study comparing union, re-operation and complication rates between autograft and morselized allograft as filler for the medial gap created in MOW-HTO.

Method: Forty patients who underwent MOW-HTO for sympathetic varus deformity with the use of autograft bone were matched for age, sex, body mass index, deformity and deformity correction with 40 patients who underwent the same procedure with the use of morselized bone allograft. The operative technique utilized, type of hardware fixation and rehabilitation program were similar for both groups. The primary outcome assessed was union rate as evaluated on radiographs by two independent blinded examiners. Re-operation and complication rates were assessed as secondary outcomes.

Results: A total of 73/80 patients in the study (91%) developed union, 4/80 (5%) developed nonunion, and 3/80 (4%) required early revision. The union rate was 95% and 88% in the autograft and allograft groups respectively. Three percent in the autograft and 8% in the allograft groups developed nonunion (p=0.64). Thirteen percent of the autograft patients required re-operation compared to 18% from the allograft patients (p=0.53). Complications were encountered in 28% of the autograft group and in 23% of the allograft group (p > 0.05). There was a 10% incidence of harvest site complications in the autograft group. The average operative time was 21 minutes shorter using allograft compared with using autograft (p< 0.01).

Conclusion: No statistical significant difference was demonstrated between the groups for union, re-operation rates and overall complication rates. However, the autograft group had a significant 10% incidence of harvest site complications and a statistically significant increased operative time. We conlcude that allograft is safe and efficacious to use in valgus producing MOW-HTO. Allograft avoids harvest site complications and is associated with decreased operative time when compared to autograft.

To examine the effect of gender on outcome of high tibial osteotomy (HTO) for varus gonarthrosis at a minimum two year follow-up

Sixty-five patients (twenty-four female and forty-one male) participated in this investigation. Mean age at the time of surgery was fifty-five years and mean time to follow-up was 54.83 months. Multiple linear regression was used to estimate the strength of the association between post-operative WOMAC osteoarthritis index scores and the independent variables of gender, age, BMI, time (months from surgery) and pre and post operative mechanical axis angles (MAA) measured on standing double-leg hip-to-ankle radiographs.

This analysis revealed that none of the independent variables contributed significantly to the WOMAC outcome scores.

The results of this study indicate that gender is not a significant predictor of outome following medial opening wedge HTO. This is contrary to the view held by many.

The purpose of our study is to determine if hamstring autograft size can be predicted preoperatively. We will define a relationship between patient body size (BMI, height, and weight) and harvested graft size, as well as define a relationship between the preoperative MRI cross-sectional area (CSA) of hamstring tendons and harvested graft size. This information will be useful as a tool for preoperative planning in graft choice selection.

The pre-operative MRIs of one hundred and four patients (62M, 42F) who underwent ACL reconstruction using hamstring autografts were analyzed. Cross-sectional area (CSA) of the ST and G was measured on a single axial MRI image at the level of the knee joint. Combined CSA of both tendons was then compared to the diameter of the four-strand hamstring autograft measured intra-operatively. Patient BMI, height and weight was also compared to intraoperative hamstring autograft size. Linear regression analysis was then performed to define the relationship and predictive value of body size on graft diameter.

Mean graft size was 7.4mm (range 6 – 9). Average graft size for men and women, 7.6mm and 7.1mm, respectively. Predicting graft size from BMI: r= 0.29, R2= 0.08. Predicting graft size from height: r= 0.52, R2= 0.27. Predicting graft size from weight: r= 0.5, R2= 0.25. On preoperative MRI, the mean CSA of ST and G was 9.8mm2 (range 5.4 – 17.7) and 4.5mm2 (range 1.8 – 9.4) respectively, with a total CSA of 14.3mm2 (range 8.4 – 25). If the total CSA was greater than 12mm2, a graft of 7.0mm or greater could be predicted 93% of the time, with sensitivity and specificity, 78% and 76%, respectively, and a LR of 3.25.

Body size is a poor predictor of hamstring graft size in ACL reconstruction, and therefore a large patient does not always provide a large graft from harvested hamstring tendons. MRI assessment of hamstring tendons can be a useful tool for preoperative planning, providing a strong predictive value of graft size from a simple calculation.

Measures of lower limb alignment and knee joint load during walking were evaluated before and six months after medial opening wedge high tibial osteotomy (HTO) in ninety-five patients with knee medial compartment osteoarthritis (OA). Full-length standing radiographs were used to calculate the mechanical axis angle, and a gait analysis was performed to calculate the external adduction moment about the knee. Results indicated significant decreases in mechanical axis angle and peak adduction moment. These findings provide an indication of the early success of HTO in reducing the extent of lower limb malalignment and knee joint load during walking.

Medial opening wedge high tibial osteotomy (HTO) is intended to correct lower limb malalignment, resulting in decreased medial knee joint load and improved function. Due to the potential for the amount of alignment correction to change over time after surgery, frequent follow-up evaluations are encouraged.

To evaluate the early changes in lower limb alignment and medial knee joint load experienced during walking after medial opening wedge HTO.

Ninety-five patients (seventy-nine males, sixteen females; age range = 21–76 years; BMI range = 18.0–38.5) with knee joint OA affecting primarily the medial compartment underwent radiographic and gait analyses pre-surgically and six months following HTO. Full-length standing radiographs were obtained on both occasions and used to measure the static mechanical axis angle. Three-dimensional kinetic and kinematic data were also collected and combined to calculate the external knee joint adduction moment, an indirect measure of knee joint load. Paired t-tests indicated the mechanical axis angle (mean decrease = 8.32 degrees, 95% CI = 7.54,9.10) and peak external knee joint adduction moment (mean decrease = 1.61%BW*ht, 95% CI = 1.25,1.95) significantly decreased post-operatively (p< 0.001). These results indicate less varus angulation and reduced medial knee joint load following HTO.

These preliminary findings suggest that medial opening wedge HTO is an effective surgical treatment for improving alignment and reducing knee joint load.

Although these early results are promising, future research is required to determine the long-term success of this surgery in the treatment of knee OA.

Funding:

CIHR, NSERC, Arthrex Inc.

Introduction The goal of HTO is to re-align the mechanical axis to neutral or over corrected.

Methods I present a personal series of 22 opening wedge high tibial osteotomies in 20 patients with chronic posterior or posterolateral instability. Pre-operatively standing long leg views and a lateral view in extension are required to asses the mechanical axis and the posterior slope of the tibia. The osteotomy needs to be tailored to the pathology, remembering that increasing the posterior slope of the tibia worsens an ACL but improves a PCL deficit.

Results Sixty percent of the patients reported that knee stability was significantly better, 35% somewhat and 5% no better. All 20 patients reported that they would undergo the procedure again. Alignment was altered a mean of four degrees valgus and posterior tibial slope was increased by a mean of seven degrees.

Conclusions Simultaneous correction of knee mal-alignment and tibial slope by an opening wedge osteotomy can produce good functional and radiographic results.

In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.

The pathology of pulp space infection is discussed. It is recommended that a direct incision which is localised precisely to the abscess site, even if the incision is in the tactile pad, is better than a lateral incision, which fails to maintain drainage, causes longer incapacity, and may injure the digital nerve and give rise to causalgia. Fifty cases of pulp space infection in which a direct incision was used are reviewed.