The coronal plane high tibial osteotomy. Part 1: a clinical and radiographic analysis of intermediate term outcomes

Changes in posterior tibial slope angle in patients undergoing open-wedge high tibial osteotomy for varus gonarthrosis

PURPOSE

In this study, postoperative changes in the posterior tibial slope angle and clinical outcomes following open-wedge high tibial osteotomy were evaluated.

METHODS

This study included 39 knees (18 left, 21 right) of 35 patients (three male, 32 female; median age, 53 years; age range 37-64 years) with symptomatic isolated medial joint osteoarthritis who underwent open-wedge high tibial osteotomy and fixation with a Puddu plate. The patients were clinically assessed according to the Lysholm knee score, a visual analogue pain scale, and a patient satisfaction questionnaire. Radiological assessment was made according to the changes in the posterior tibial slope angle and the correlation between these changes and clinical signs. The median follow-up period was 11 years (range 7-14 years).

RESULTS

Significant improvements were observed in the preoperative and postoperative clinical scores of the Lysholm knee scale, visual analogue pain scale, and patient satisfaction questionnaire (p < 0.05). Radiological assessment showed that the posterior tibial slope angle was significantly higher during the postoperative and follow-up periods (p  0.05). There was no correlation between the postoperative Lysholm scores and the increase in the posterior tibial slope angle (p = n.s.).

CONCLUSIONS

We conclude that both the conventional Puddu plate design and its anteromedial plate placement are what increase the tibial slope after an opening-wedge proximal tibial osteotomy. Therefore, current new plate design may help preserve the posterior tibial slope angle.

LEVEL OF EVIDENCE

IV.

Prospective 5-year survival rate data following open-wedge valgus high tibial osteotomy

PURPOSE

Open-wedge high tibial osteotomy using internal plate fixation is a well-established and frequently performed treatment option for the management of medial compartment osteoarthritis (OA) in the young and active patients. The present study provides survival rate and functional outcome preoperatively and after 6, 12, 24, 36 and 60 months following open-wedge high tibial osteotomy. Hypothesis of the authors was high survival rates after 5 years with still remaining satisfying functional results.

METHODS

Sixty-two patients suffering from tibial conditioned knee joint varus deformity and medial compartment OA that underwent high tibial osteotomy using an internal plate fixator (TomoFix™, Synthes) were included. Functional outcome was evaluated prior to surgery and in the further clinical course using standard instruments (IKDC score, Lysholm score). Treatment failure was defined as the need for total knee arthroplasty (TKA).

RESULTS

Fifty-one patients (mean age 46.8 ± 10.2 years) were available at a mean of 60.5 (SD ± 2.5) months (follow-up rate 82.3 %) postoperatively. Sixty-month IKDC (69.4 % SD ± 18.6) and Lysholm (76.6 SD ± 20.5) improved significantly when comparing with preoperative values (IKDC 44.6 SD ± 17.8; Lysholm 52.1 SD ± 20.8). Two of 51 subjects underwent TKA, resulting in a survival rate of 96 % among those patients followed (51 of 60; 85 %). Overall complication rate was 8.6 %.

CONCLUSION

With a survival rate of over 96 % at 5 years, high tibial osteotomy seems to be a reliable treatment option with satisfying clinical outcome. Functional outcome was stable following 60 months. While a delay of the necessity for TKA seems likely with regard to the survival rate demonstrated in this article, possible avoidance needs to be demonstrated by longer follow-up studies.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

The long-term outcome of open-wedge osteotomy of the proximal tibia with hemicallotasis

We report the long-term outcome of 33 patients (37 knees) who underwent proximal tibial open-wedge osteotomy with hemicallotasis (HCO) for medial osteoarthritis of the knee between 1995 and 2000. Among these, 29 patients with unilateral HCO were enrolled and 19 were available for review at a mean of 14.2 years (10 to 15.7) post-operatively. For these 19 patients, the mean Hospital for Special Surgery knee score was 60 (57 to 62) pre-operatively and 85 (82 to 87) at final follow-up (p < 0.001; paired t-test). The femorotibial angle and tibial inclination angle (IA) were measured at short-term follow-up, one to four years post-operatively, and showed no significant subsequent changes. The clinical scores and radiological measurements showed little change over time. One patient required conversion to total knee replacement during this time. These results suggest that the coronal angle achieved at operation is maintained at long-term follow up after HCO without alteration of the IA, providing a good long-term clinical outcome.

Cite this article: Bone Joint J 2014;96-B:467–72.

A morphometric study of normal and varus knees

PURPOSE

The aim of the study was to investigate varus and normal knee morphologies to identify differences that may affect knee replacement alignment or design for varus knees.

METHODS

Computed tomography scans of varus and normal knees were analyzed, and geometric shapes, points and axes were fit to the femur and tibia independently. These points were then projected in the three anatomical planes to measure the variations between the two groups.

RESULTS

In the femur, varus knees had less femoral anteversion (p < 0.0001) and a larger medial extension facet (p < 0.05) compared with normal knees. In the tibia, the tubercle was found to be externally rotated in varus knees (12°), with a significant increase in the coronal slope (p = 0.001) and the extension facet angle (p = 0.002).

CONCLUSIONS

The study highlighted the differences and similarities found between the two groups, which raises awareness on changes required during surgical intervention and component placement or design for a varus knee. This is particularly relevant for the design of patient-specific instrumentation and implants.

LEVELS OF EVIDENCE

Diagnostic study, Level III.

Open-wedge osteotomy using an internal plate fixator in patients with medial-compartment gonarthritis and varus malalignment: 3-year results with regard to preoperative arthroscopic and radiographic findings

PURPOSE

Our purpose was to evaluate the 3-year clinical results of patients with medial-compartment osteoarthritis of the knee and varus malalignment who underwent open-wedge high tibial osteotomy (HTO) with an internal plate fixator (TomoFix; Synthes, Solothurn, Switzerland). Clinical results are correlated with arthroscopic and radiographic findings at the time of surgery.

METHODS

This study included 69 patients with a minimum follow-up of 36 months who underwent open-wedge HTO for medial-compartment osteoarthritis of the knee. Knee function was assessed before surgery and at 6, 12, 24, and 36 months after HTO by use of subjective International Knee Documentation Committee and Lysholm scores. Arthroscopic findings before HTO and radiographic assessment of the metaphyseal deformity of the proximal tibia (tibial bone varus angle) were correlated with clinical outcome.

RESULTS

A significant continuous increase in International Knee Documentation Committee score from 47.25 ± 18.71 points before surgery to 72.72 ± 17.15 points at 36 months after HTO was found (P < .001). Grade of cartilage damage of the medial compartment and partial-thickness defects of the lateral compartment did not significantly influence clinical outcome (P > .05 at all time points). The tibial bone varus angle was correlated significantly with greater improvement and better clinical outcome after HTO (P < .01). The overall complication rate of 8.6% was mostly related to surgical causes; nevertheless, a high proportion of patients reported discomfort related to the implant at some point during the follow-up period (40.6%).

CONCLUSIONS

Open-wedge osteotomy by use of the TomoFix system leads to reliable 3-year results. Results do not depend on the severity of medial cartilage defects, whereas partial-thickness defects of the lateral compartment seem to be well tolerated. The prognostic relevance of patellofemoral cartilage defects remains unclear. Local irritation of the implant was observed in a significant number of patients.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Reliability of image-free navigation to monitor lower-limb alignment

Proper alignment of the mechanical axis of the lower limb is the principal goal of a high tibial osteotomy. A well-accepted and relevant technical specification is the coronal plane lower-limb alignment. Target values for coronal plane alignment after high tibial osteotomy include 2 degrees of overcorrection, while tolerances for this specification have been established as 2 degrees to 4 degrees. However, the role of axial plane and sagittal plane realignment after high tibial osteotomy is poorly understood; consequently, targets and tolerance for this technical specification remain undefined. This article reviews the literature concerning the reliability and precision of navigation in monitoring the clinically relevant specification of lower-limb alignment in high tibial osteotomy. We conclude that image-free navigation registration may be clinically useful for intraoperative monitoring of the coronal plane only. Only fair and poor results for the axial and sagittal planes can be obtained by image-free navigation systems. In the future, combined image-based data, such as those from radiographs, magnetic resonance imaging, and gait analysis, may be used to help to improve the accuracy and reproducibility of quantitative intraoperative monitoring of lower-limb alignment.