No correction angle loss with stable plates in open-wedge high tibial osteotomy

PURPOSE

The aim of this study was to compare the clinical and radiological results of the wedge plate and locking plate systems in open-wedge high tibial osteotomy.

METHODS

Between 2007 and 2010, the wedge plate was used as the fixation device for osteotomy to treat a total of 67 patients; from 2009 to 2010, the locking plate was used in 19 patients. Matching for gender, age, body mass index (BMI), and articular cartilage status, 19 pairs of wedge plate and locking plate cases were enrolled in a 1:1 retrospective matched-pair analysis. Clinical data were collected and scored using the visual analogue scale and the International Knee Documentation subjective score. Additionally, pre-operative, immediate post-operative, and last follow-up radiographs were obtained to assess changes in the hip-knee-ankle (H-K-A) angle and posterior tibial slope.

RESULTS

No significant differences in gender, age, BMI, follow-up period, and articular cartilage status were found between the groups. Although the initial correction of the H-K-A angles, 8.9° ± 1.9° and 9.4° ± 4.2° for the wedge plate and locking plate groups, respectively, was not significantly different, a significant difference (P = 0.046) in the final correction angles, 7.2° ± 2.1° and 9.4° ± 4.4°, respectively, was found. The increase in the posterior tibial slope, 0.5° ± 2.0° and 3.2° ± 2.6°, for the wedge plate and locking plate groups, respectively, was significantly different (P = 0.010). When classified according to the correction angle, we found that when the initial correction angle exceeded 10.0°, an average correction loss of 2.9° ± 0.5° was observed in the wedge plate group, whereas an average increase in the posterior tibial slope of 5.8° ± 1.6° was evident for the locking plate group.

CONCLUSIONS

At 2 years post-operatively, the final correction angles of the wedge and the locking plate groups differed significantly, and the wedge plate group had a smaller increase in the posterior tibial slope than the locking plate group.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

Second-look arthroscopic assessment of cartilage regeneration after medial opening-wedge high tibial osteotomy

PURPOSE

The purposes of this study were to evaluate regeneration of the articular cartilage after medial opening-wedge high tibial osteotomy for knees with medial-compartment osteoarthritis and to assess the clinical outcome and cartilage regeneration according to the postoperative limb alignment at 2 years postoperatively.

METHODS

The study involved 159 knees in 159 patients. For evaluation of cartilage degeneration, the International Cartilage Repair Society grading system was used for arthroscopic grading on initial arthroscopy during high tibial osteotomy. The patients underwent a second-look arthroscopic evaluation of the articular cartilage at the time of removal of the plate, an average of 2 years after the initial osteotomy. For evaluation of cartilage regeneration, the articular cartilage was classified into 2 stages as no regenerative change (grade 1) or white scattering with fibrocartilage, partial coverage with fibrocartilage, or even coverage with fibrocartilage (grade 2) on second-look arthroscopy. Maturation of the cartilage regeneration was defined as even coverage with fibrocartilage. "Immaturation" of the cartilage regeneration was defined as white scattering with fibrocartilage or partial coverage with fibrocartilage. Clinical evaluations were performed by use of Knee Society scores preoperatively and at 2 years postoperatively. We divided the knees into 3 groups according to the postoperative limb alignment. Group A comprised knees with a mechanical tibiofemoral angle of 0° or less. Group B comprised knees with a mechanical tibiofemoral angle greater than 0° and less than 6°. Group C comprised knees with a mechanical tibiofemoral angle of 6° or greater.

RESULTS

Grade 2 regeneration was achieved in the medial femoral condyle articular cartilage in 92% of knees and in the medial tibial plateau articular cartilage in 69% of knees. Maturation of the cartilage regeneration was found in the medial femoral condyle articular cartilage in 4% of knees and in the medial tibial plateau articular cartilage in 1% of knees. At follow-up, no significant differences were seen between clinical outcomes and initial cartilage degeneration (P = .338) or cartilage regeneration (P = .699). Regeneration of the medial femoral condyle articular cartilage was found in 75% of group A knees, 95% of group B knees, and 92% of group C knees. Significant differences were seen between cartilage regeneration and clinical outcomes (P = .001), as well as postoperative limb alignment (P = .018). Clinical and regeneration results were better in group B than in groups A and C.

CONCLUSIONS

The degenerated cartilage of the medial femoral condyle and medial tibial plateau could be partially or entirely covered by newly regenerated cartilage at 2 years after adequate correction of varus deformity by medial opening-wedge high tibial osteotomy without cartilage regeneration strategies.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Comparative study of medial opening-wedge high tibial osteotomy using 2 different implants

PURPOSE

The purpose of this study was to perform a retrospective clinical and radiographic evaluation after opening-wedge high tibial osteotomy (HTO) using a short spacer plate (Aescula; B. Braun Korea, Seoul, South Korea) and rigid long plate (TomoFix plate; Mathys, Bettlach, Switzerland) at follow-up 2 years postoperatively.

METHODS

We performed 94 opening-wedge HTOs with the Aescula plate (group I) and 92 HTOs with the TomoFix plate (group II). Patients underwent clinical and radiographic evaluations preoperatively and at 2 years postoperatively. Clinical evaluations were performed with Knee Society scores. Radiographic analysis included the mechanical tibiofemoral angle (mTFA) and the slope of the tibia angle with preoperative and postoperative full weight-bearing anteroposterior whole-leg views, as well as anteroposterior, lateral, and Merchant views of the knee. We measured the mTFA. In addition, we evaluated the complications in each group. The follow-up period was 2 years.

RESULTS

At follow-up 2 years postoperatively, we observed an overall complication rate of 38% in group I and 26% in group II (P = .083). We found plate-related complication rates of 20% in group I and 9% in group II (P = .039). Plate-related complications included loss of correction, fracture of the tibial plateau, screw failure, malunion, and fracture of the lateral cortical bone. The mean mTFA was -6.0° ± 3.2° in group I and -4.6° ± 2.8° in group II preoperatively (P = .262). The mean mTFA was 1.0° ± 3.1° in group I and 1.5° ± 2.3° in group II at the latest follow-up (P = .034). In group I, the mean Knee Society knee score and function score were 60.0 ± 12.9 and 57.9 ± 26.8, respectively, preoperatively. They improved to 92.1 ± 8.1 and 89.0 ± 15.1, respectively, at follow-up (P = .001 and P = .001, respectively). In group II, the mean Knee Society knee score and function score were 57.5 ± 14.8 and 57.4 ± 22.1, respectively, preoperatively. They improved to 95.5 ± 5.4 and 95.0 ± 7.6, respectively, at follow-up (P = .001 and P = .001, respectively). In addition, the mean postoperative knee score and function score in group II were higher than those in group I (P = .001 and P = .001, respectively).

CONCLUSIONS

We have shown a high plate-related complication rate and a significant loss of correction during a short-term follow-up period (2 years) after opening-wedge HTO using the new short spacer HTO plate compared with the rigid long plate.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.