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.

Purpose: Medial Opening Wedge High Tibial Osteotomy (MOWHTO) is a joint preserving procedure of the knee. Currently we understand the anatomical changes occurring in the varus/valgus plane, but our understanding of other anatomical changes are limited. The objective of this study is to determine immediate anatomical changes occurring about the knee following MOWHTO. Our hypothesis is that anatomical changes occur in all planes of motion. More specifically, we hypothesize that posterior tibial slope is increased and patellar height is decreased immediately following the osteotomy.

Methods: This study was prospective in design. Patients with knee OA were evaluated according to strict inclusion and exclusion criteria. Pre-operative clinical assessment, radiographic evaluation, and patient assessment scores were performed. Intraoperatively, patients had radiostereometric analysis (RSA) beads placed in a predetermined pattern. Intraoperative radiographs were taken. The MOWHTO was then performed. A second radiograph was then taken following the osteotomy. The radiographs were analysed using dedicated RSA computer software to determine anatomical changes.

Results: Eleven patients were included in this study. Average age was 50 years. Mean error and condition number were 0.70 and 74 respectively, indicating highly accurate and reliable results. Analysis of the proximal tibia showed an average valgus correction angle of 8.69 degrees. The average osteotomy size was 12.5mm (9–17.5). Posterior tibial slope increased on average by 2.07 degrees (+5.91–−1.56). Analysis of the patella revealed anatomical changes occurred in all planes. However, the only consistent alteration was a decrease in patellar height by an average of 8.16mm (1.79–13.17). Additionally, there was a consistent increase in patellar tendon length by 5.30mm (2.38–7.34).

Conclusions: Using RSA in MOWHTO for the first time, we were able to demonstrate a useful and accurate measurement tool for this procedure. We found there were many immediate anatomical changes following MOWHTO that are inconsistent and not well understood. There were, however, several anatomical changes that remained consistent among all subjects. Patellar height decreased, patellar tendon length increased, and posterior tibial slope demonstrated an average increase.

Purpose: To clinically and radiologically evaluate medium term outcome of a patient cohort age 55 years or older at the time of medial opening wedge high tibial osteotomy (MOWHTO).

Methods: Between January 1997 and January 2003, 60 patients (52 males) underwent 66 MOWHTOs. Following a systematic chart review 56 returned for follow up. Outcomes measures were KOOS, LEFS, SF-12, Cincinnati, Tegner scores, a new activity score and physical examination. Routine knee and long leg standing radiographs were compared to pre and early postoperative radiographs.

Results: Thirteen patients were not assessed further, 6 (7 MOWHTOs) had undergone total knee arthroplasty (TKA), 3 had passed away and 4 were lost to follow up. Thus the probability of survival (not converting MOWHTO to TKA) was 0.966 at 3 years, 0.927 at 4 years and 0.878 at 5 years. Quality of life, functional status and general health of the remaining 47 patients (52 HTOs) with a mean age of 62 years (55–75) at the time of surgery were assessed. At a mean follow up of 62 months (26–98), on the author’s activity score, 83% performed at least one high impact activity at moderate to high intensity an average of 4–7 times weekly and 6% did not participate in any sport. Average participation in activities/sports was 3 per person at a participation level of 4.6 (Tegner). The mean Cincinnati score was 75% (SD=23, 14–95%). Mean scores for the KOOS and LEFS were 66% (SD=22,7–99%) and 49 (SD=18, 5–80) respectively. The mean physical component score of the SF-12 was 42 (SD=11, 21.7–60.4) and the mean mental component score, 54 (SD=11, 26–68). Seventy–two percent were fully weight bearing by 3 months. There were 6 revisions performed for a combination of delayed and non-unions.

Conclusions: MOWHTO remains a viable alternative for patients over the age of 55 with knee osteoarthritis and varus malalignment who would otherwise be candidates for arthroplasty and particularly for those wishing to maintain or regain a high level of activity.

Purpose: To compare lateral closing to medial opening wedge HTO for a similar angle of correction with regard to change in proximal tibial bony anatomy and posterior cruciate ligament tibial attachment integrity following standard tibial arthroplasty resection.

Methods: Ten cadaveric lower limbs were randomized by side to receive a 12° lateral closing or 12.5mm medial opening wedge HTO. Anteroposterior, lateral and long leg AP radiographs were performed before and after each osteotomy. Pre and post osteotomy measurements of the coronal proximal tibial angle (PTA), sagittal tibial slope and anatomical femorotibial angle were completed and change in angles calculated. Prior to osteotomy, the tibial PCL attachment area was calculated. Post osteotomy, a standardized tibial arthroplasty resection was performed and the remaining percentage PCL attachment area recorded.

Results: Initial radiographs demonstrated little variation between matched pairs. Compared to the medial opening wedge group, the lateral closing wedge specimens demonstrated a statistically significant greater mean change in the PTA of 3.5° (95% C.I., 2.0 to 5.1°, p = 0.003) and an overall tendency for posterior tibial slope reduction with a mean change of −3.4 ± 4.9°. The average osteotomy angle in the medial opening wedge specimens was 11.9 ± 0.7°. Following tibial arthroplasty resection, there was a significant difference in the remaining PCL tibial attachment percentage area of 84.6 ±14.9 % for medial opening wedge and 50.8 ± 19.3 % for lateral closing wedge for a statistically significant mean difference of 33.8 % (95% C.I. 5.1 to 62.4, p = 0.031).

Conclusions: Despite similar correction angles of 12° for lateral closing and 11.9° for medial opening, the former specimens demonstrated a greater alteration in proximal tibial bony anatomy compared to the latter. In the lateral closing wedge group, the tendency to reduce posterior tibial slope and produce a greater than anticipated change in PTA had a significant effect on the integrity of the PCL’s tibial attachment following tibial arthroplasty resection.

Thirty-six patients with anterior cruciate ligament (ACL) insufficiency and varus malalignment were treated with combined ACL reconstruction and medial opening wedge high tibial osteotomy (HTO). Average follow-up was twenty-five months. All patients had improved ligamentous stability and twenty-five patients returned to full activities. Osteotomy union rate was 100%, mechanical axis angle was corrected from six degrees varus to neutral and the mechanical axis deviation was corrected from 2cm medial to 1cm lateral. We experienced four complications, including one deep infection. Combining ACL reconstruction and HTO simultaneously accomplishes a ligamentously stable knee with corrected alignment, allowing patients to return to activity.

To determine clinical outcome after combined ACL reconstruction and medial opening wedge high tibial osteotomy (HTO).

ACL reconstruction with medial opening HTO can be a beneficial procedure in properly selected patients presenting with complaints of both pain and instability. Correction of varus mal-alignment may provide protection for articular cartilage and improve joint stability.

Concomitant medial opening HTO performed at time of ACL reconstruction allows patients to return to activities after one procedure with a ligamentously stable knee, corrected alignment, and potential protection of articular cartilage.

Thirty-six patients who underwent ACL reconstruction along with medial opening HTO were retrospectively evaluated postoperatively at an average of twenty-five months.

Average age was thirty-seven years at time of surgery. All patients were recreationally active. Pre-operatively all patients had knee pain and instability, varus angulation, and twenty-two patients had previous knee surgery. Semitendinosus/gracilis grafts were used in all patients, and osteotomies were fixed with Puddu plates. Postoperatively patients had improved ligmentous stability with radiographic and clinical evidence of osteotomy healing, and all but nine patients have returned to full activities. We experienced four complications: one ACL failure, one case of anterior laxity with tibial tunnel widening, and two infections. On average, MAD was corrected from 22mm medial to 10mm lateral; mechanical axis angle was corrected from 6.4 degrees of varus to 0.2 degrees of valgus; tibial slope was increased from 9.1 degrees to 10.3 degrees, and patellar height ratio was decreased from 0.9 to 0.8.

The peak external knee adduction moment during walking gait has been proposed to be a clinically useful measure of dynamic knee joint load in patients with knee osteoarthritis. However, there is limited information about the reliability of this measure, or its ability to detect change. The test-retest reliability and sensitivity to change of peak knee adduction moments were evaluated in thirty patients with varus gonarthrosis. Indices of relative and absolute reliability were excellent (intra-class correlation coefficient = 0.85, standard error of measurement = 0.36 % BW*Ht), and the sensitivity to change following high tibial osteotomy was high (standardized response mean = 1.2).

To estimate the test-retest reliability, measurement error and sensitivity to change of the peak knee adduction moment during gait.

Thirty patients (44”11 yrs, 1.7”0.09 m, 87”20 kg, twenty males, ten females) with varus gonarthrosis underwent gait analyses on two pre-operative test occasions within one week, and on a third test occasion six months after medial opening wedge high tibial osteotomy. Three-dimensional kinematic and kinetic gait data were collected during self-paced walking and used to calculate the peak knee adduction moment.

An intraclass correlation coefficient of 0.85 (95%CI: 0.71, 0.93) indicated excellent relative reliability, and a standard error of measurement of 0.36 %BW*Ht (95%CI: 0.29, 0.49) indicated low measurement error. The peak knee adduction moment after surgery (1.66”0.72 %BW*Ht) was significantly (p< 0.001) lower than before surgery (2.58”0.72 %BW*Ht). A standardized response mean of 1.2 (95%CI: 0.77, 1.6) indicated the size of this change was large.

Based on 95% confidence levels, these results suggest the error in an individual’s peak knee adduction moment at one point in time is 0.70 % BW*Ht, the minimal detectable change in an individual’s peak adduction moment is 1.0 %BW*Ht, and it is sensitive to change following treatment.

The peak knee adduction moment during gait has appropriate reliability for use in studies evaluating the effect of treatments intended to decrease the load on the knee. When considering measurement error, the knee adduction moment is also appropriate for clinical use in evaluating change in individual patients.

Funding: CIHR, 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.

Introduction: It has been proposed that tunnel widening in ACL reconstructions is due to excessive graft tunnel motion secondary to elastic fixation.

Aim: To determine whether techniques which fix the graft closer to the joint (interference screws), eliminate the bungy cord and are stiffer will decrease tunnel widening. The clinical significance of tunnel widening is examined.

Method: Two hundred and fifty nine patients were evaluated prospectively. Four fixation methods were evaluated. Sixty-nine were reconstructed using Endobuttons and staples (elastic fixation). Forty-eight were subjects reconstructed with a bone mulch screw and staples, 55 patients were reconstructed with metal interference screws and 87 with bioabsorbable interference screws. Patients underwent a clinical examination, IKDC, Cincinnati knee score and KT-1000 testing one year post-operatively. These factors were correlated with tunnel widening. Tunnel widening was determined using magnification adjusted AP and lateral radiographs using Scion Image software.

Results: Tunnel widening occurred with all the fixation methods. Mean tunnel area increased 122% for the Bioscrew, 89% for the metal interference screw, 76% for the bone mulch screw and 36% for the Endobutton (ANOVA p=< 0.0001). Tunnel widening did not correlate with increased laxity, poor IKDC or Cincinnati knee scores.

Conclusions: Tunnel widening occurred with both elastic and rigid fixation methods. Tunnel widening could not be avoided by fixing the graft closer to the joint or eliminating the ‘bungy cord’. Graft tunnel motion was not the sole cause of tunnel widening in ACL reconstruction. Tunnel widening did not correlate with poor outcome in the short term.

We reviewed 1567 elective knee replacements performed between 1980 and 1990, using either the Total Condylar prosthesis with an all-plastic tibial component, or the Kinematic prosthesis which has a metal tibial tray. The ten-year probability of survival was 92.1% for the Total Condylar design and 87.9% for the Kinematic. The difference was mainly due to 16 revisions required in the Kinematic series for fracture of the metal base-plate. This was the most common cause of aseptic failure in this group.

These fractures were strongly associated with a preoperative varus deformity (hazard ratio (HR) 8.8) and there was a slightly increased risk in males (HR 1.9) and in osteoarthritic knees (HR 1.8). In the nine fractures which occurred within four years of primary implantation (group 1), failure to correct adequately a preoperative varus deformity and the use of a bone graft to correct such a deformity were both strongly associated with fracture (HR 13.9 and 15.8, respectively). In eight fractures which occurred more than five years after primary replacement (group 2) we could detect no significant risk factors.

Early complications occurred in two patients after the 16 revision procedures for tray fracture. One had a deep infection and the other refracture of the tray.

Destruction of the articular cartilage is the first change seen on gross examination of the knee in osteoarthritis. Weight-bearing radiographs are conventionally taken with the knee in full extension. Biomechanical studies have shown, however, that the major contact stresses in the femorotibial articulation occur when the knee is flexed about 28 degrees. Arthroscopy has confirmed that cartilage loss occurs in a more posterior portion of the femoral condyles than is revealed by radiographs taken in full extension. The 'standing tunnel view' is a weight-bearing postero-anterior radiograph taken with the knee in 30 degrees of flexion. The radiographs of 64 patients have been used to compare the conventional with the standing tunnel view. In 10 knees in which the conventional view suggested normal cartilage the standing tunnel view revealed severe degeneration.

1. An operation is described for the relief of irreversible claw toes associated with prominent and painful metatarsal heads.

2. The operation is suggested as an alternative to amputation of the toes.

3. The results of the operation done on twenty patients who have been followed up for a year or longer are reported.

1. Injuries of the sternum from flexion-compression violence are described and contrasted with injuries from direct violence. The characteristic feature of flexion-compression injuries is a dislocation or fracture at or near the manubrio-sternal joint with backward displacement of the manubrium.

2. Treatment is outlined, with special reference to the indications for open reduction and wire fixation.

3. The mechanism of flexion-compression injuries of the sternum is discussed. The opinion is expressed that most of the force is transmitted to the sternum by the ribs—especially the upper ribs.

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.