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Purpose: This study documented the healing potential of degenerated articular cartilage after opening-wedge valgus high tibial osteotomy (HTO) in patients with osteoarthritis of the knee. It was hypothesized that regeneration of articular cartilage is affected by several factors, including preoperative cartilage degeneration grade, difference between the medial femoral condyle (MFC) and the medial tibial condyle (MTC), and postoperative knee alignment., Methods: Medial opening-wedge valgus HTO was performed in 131 knees of 100 patients (mean age 66 ± 7.7 years). Initial arthroscopy was performed at the time of HTO, and a second-look arthroscopy was performed at the time of plate removal (20.8 ± 6.5 months after HTO). Status of articular cartilage was assessed according to the ICRS grade. Cartilage regeneration was also evaluated by the presence of newly formed cartilaginous tissue. All subjects were followed up postoperatively at 2 years for assessment of clinical and radiographic outcomes., Results: The number of subjects in ICRS grade 1/2/3/4 was significantly altered from 0/11/53/67 preoperatively to 14/21/56/40 postoperatively in the MFC (P < 0.05) and 0/12/62/57 preoperatively to 9/24/64/34 postoperatively in the MTC (P < 0.05). Newly formed cartilaginous tissue was found in 71 % of MFCs and 51 % of MTCs. Incidence of cartilage regeneration was significantly higher in lower BMI cases, MFC, preoperatively advanced ICRS grade and overcorrected knees. Age, gender and clinical outcomes did not affect cartilage regeneration., Conclusion: Cartilage regeneration in degenerated articular cartilage is induced after opening-wedge valgus HTO, which is affected by BMI, the difference between the MFC and MTC, preoperative cartilage degeneration grade, and postoperative limb alignment. Therefore, patient selection by BMI rather than age, and surgical techniques maintaining valgus knee alignment should be considered for cartilage regeneration., Level of Evidence: Level IV, therapeutic case series.

It has been predicted that significant stress will be applied to the plate and lateral cortical hinge of an osteotomy site when early full weight bearing is commenced after an open wedge high tibial osteotomy. We hypothesized that the stress concentration on the plate or at the lateral cortical hinge would be reduced by inserting bone substitutes into the osteotomy gap. Two different types of tibia model were investigated: Group A, fixation with TomoFix with the osteotomy site left as an open space; and Group B, two beta-TCP wedges are inserted into osteotomy site and fixed with TomoFix. Stress at five points was measured using strain gauges. Specimens were mounted onto a testing machine with an FTA (femoro-tibial angle) of 170 degrees . Cyclic load tests and an ultimate load test were then performed. The mean stress on the plate was measured at 15.5+/-1.8Mpa in Group A. On the other hand, this value in Group B was only 9.52+/-2.1Mpa and this was a significant difference (P<0.01). The mean stress on the lateral hinge in Groups A and B was 3.31+/-0.5 and 2.49+/-0.2, respectively which was also a significant difference (P<0.05). The mean maximum breaking load in Group A was 2500+/-280N and in Group B 4270+/-420N which was a significant difference (P<0.01). Hence, for OWHTO procedures, the use of beta-TCP wedges and TomoFix is thus likely to improve the initial axial and possibly rotational stability at the osteotomy site in comparison with methods that leave the osteotomy gap open.

Since 1969 corrective osteotomy has been performed at our institute in young patients (under 40 years) with bowlegs, knock knees and flexion or rotational deformities around the knee. Fifty-seven knees (29 left, 28 right) of 45 patients (19 boys, 26 girls) were followed-up for a period ranging from 30 to 38 years in seven patients with seven knees, from 20 to 29 years in nine patients with 11 knees, and from ten to 19 years in 29 patients with 39 knees. Supracondylar femoral osteotomy was performed on 12 knees (11 patients), high tibial osteotomy above the tibial tuberosity on eight knees (six patients) and below the tuberosity on 37 knees (28 patients). At the final follow-up (age range 42-73 years), all of the deformities were satisfactorily corrected, with no symptoms apart from nine knees, seven of which had dull pain after strenuous sport with osteophytes, etc. in the radiograph. Total knee arthroplasty was performed in the remaining two knees, at ten and 26 years, respectively, after the initial osteotomy. Osteoarthritis developed in the contralateral knee to the initial osteotomy in two patients after 34 years at age 73 and after 33 years at age 67.

The treatment of patients with osteoarthritic knees accompanied by ipsilateral osteoarthritic ankles is not well documented. We here report both clinical results and radiographic evaluations of such patients treated using a high tibial osteotomy (HTO). HTO was performed on 16 knees of 10 patients (all women with a mean age; 68 years; range 58 to 73 years) who had a varus deformity of both their legs as a result of medial compartmental osteoarthritis of their knees. The Hospital for Special Surgery's (HSS score) knee scoring system and the clinical rating system for the ankle-hindfoot by Kitaoka (AOFAS) were used to evaluate the patients clinically before and after HTO. Radiographic findings were measured using antero-posterior one-leg weight bearing radiographs of the whole lower extremity taken before surgery. The mean time of follow-up was 8 years (range, 4-10 years). The HSS score improved from 54 to 91 points after HTO and the mean ankle score improved significantly from 54 to 86 points. After HTO also, the alignment of the knees changed from 6 degrees varus to 12 degrees valgus. The decrease of the inclination angle of the tibial axis changed from 10 degrees laterally to - 2 degrees medially and the talar tilt angle improved from 18 degrees to 6 degrees resulting in an improvement of the ankle congruity. HTO, which can correct the total alignment of the lower extremity, is thus recommended as one of more effective surgical procedures for patients with an ipsilateral osteoarthritis of the knee and ankle.

A long-term follow-up study was performed on 75 knees of 53 patients after high tibial valgus osteotomy. The earlier results have previously been reported. There were 15 knees in 11 men and 60 knees in 42 women. The follow-up period ranged from 15 to 28 years with a mean of 19 +/- 3 years. The age at osteotomy ranged from 46 to 73 years with a mean of 59.6 +/- 6.7 years. The diagnosis was medial compartmental osteoarthritis (OA) in 68 knees (46 patients) and spontaneous osteonecrosis of the medial femoral condyle in 7 knees (7 patients). Valgus osteotomy was performed above the tibial tuberosity, with removal of a laterally based wedge in all cases, aiming for anatomical valgus angulation of 10 degrees . The American Knee Society Score showed a Knee Score of 37 +/- 20 and a Function Score of 38 +/- 16 preoperatively and 87 +/- 13 and 80 +/- 19 at the final 15 to 28 years' follow-up. The femoro-tibial angle in standing was 186 +/- 6.5 degrees (6 degrees of anatomical varus angulation) before and 171 +/- 7.5 degrees (9 degrees of anatomical valgus angulation) at final follow-up (p < 0.0001), with no apparent loss of limb alignment.

The aim of the current study was to document regeneration of the articular cartilage after correction of varus deformity for osteoarthritis of the knee. The repair of articular cartilage after high tibial valgus osteotomy for medial compartmental osteoarthritis was observed in 146 knees of 115 patients. The mean age of the patients at osteotomy was 65+/-7 years (range 47-80). Observations were made through an arthrotomy at the time of removal of the blade plate, an average of 2 years after the initial osteotomy. Regeneration of the degenerated cartilage was classified into three stages. There were no regenerative findings (Stage A) in 13 knees; partial regeneration with fibrocartilaginous tissue (Stage B) in the previous degenerated area (Stage B) in 86 knees; and total coverage by new regenerated fibrocartilage or hyaline-like cartilage (Stage C) in 47 knees. Mature regeneration (Stage C) was observed more frequently in the knees with increased width of the medial joint space after high tibial osteotomy than in those with unchanged width (P<0.01), and in the knees with more than 5 degrees of anatomical valgus angulation after osteotomy than in those with less than 5 degrees (P=0.05). Even the knees with eburnation of subchondral bone in the weight-bearing portion showed Stage C regeneration in 26 out of 80, in contrast with no regeneration in two knees with degenerated cartilage remaining. O'Driscoll's histological and histochemical grading score was higher in the Stage C group (P<0.02). The weight-bearing portion of the medial femoral condyle with exposed bone was concluded to be partially or entirely covered by newly regenerated cartilage after 1 year after adequate correction of varus deformity by high tibial osteotomy without antologous chondrocyte implantation.

Background: The aims of this study were to investigate the results of opening-wedge high tibial valgus osteotomy in patients with medial compartment osteoarthritis of the knee and to examine the usefulness of hydroxyapatite wedges as the supporting material., Methods: Medial opening-wedge osteotomy was performed in twenty-one osteoarthritic knees in eighteen patients who had a mean age of 66.6 years. The mean duration of follow-up was 78.6 months. A medial transverse osteotomy was performed proximal to the tibial tuberosity, with the most lateral 10% of the tibia left intact. The medial side of the osteotomy site was opened to the desired angle of correction. Two hydroxyapatite wedges of the same size (5.0, 7.5, or 10.0 mm) were inserted into the opened osteotomy site along with bone grafts, and the fragments were fixed with two plates. The angle of correction could be adjusted by altering the direction of wedge insertion. The goal was to achieve a final standing alignment of 10 degrees of anatomical valgus angulation., Results: All patients had pain relief and improvement in walking ability after the osteotomy. The mean knee and function scores of the American Knee Society were 60.2 +/- 5.3 and 48.1 +/- 10.4 points, respectively, before the osteotomy and 94.3 +/- 7.3 and 93.1 +/- 9.8 points, respectively, at the time of the final follow-up. Limb alignment, expressed as the standing femorotibial angle, was corrected from 180 degrees +/- 2.9 degrees preoperatively to 169.7 degrees +/- 3.7 degrees (10.3 degrees of anatomical valgus angulation) at the time of the latest follow-up. There were no cases of recurrence of varus deformity or collapse of the hydroxyapatite wedges., Conclusions: After a mean duration of follow-up of 6.6 years, we found that the medial opening-wedge osteotomy of the proximal part of the tibia provided satisfactory clinical results for patients with osteoarthritis of the knee. Use of the porous hydroxyapatite wedges resulted in no collapse or subsidence at the osteotomy site., Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See p. 2 for complete description of levels of evidence.

In order to obtain better range of motion in knees with osteoarthritis, medial and lateral parapatellar retinaculo-capsular release operations were performed at the time of high tibial osteotomy, with fixation using dual plating on medial compartmental knee osteoarthritis (29 knees) or spontaneous osteonecrosis of the medial femoral condyle (15 knees). At removal of the blade plate, 1 to 2 years after the initial osteotomy, the same release procedures were performed together with resection of adhesive soft tissue and resection of osteophytes, which were obstacles to full flexion. A grading system (Grade 0-3) was proposed to evaluate the duration (min) of formal floor sitting. After these procedures, the patients were able to sit on the floor with 155-165 degrees of flexion for more than 30 min (Grade 3) in 20 knees, for 10-29 min (Grade 2) in seven, for less than 10 min (Grade 1) in nine and were unable to sit on the floor (Grade 0) in eight knees. Maximum knee flexion and total range of motion were 142+/-8.4 degrees and 137+/-11 degrees before and 152+/-6.6 degrees and 151+/-7.4 degrees after surgery, respectively. The American Knee Society Knee Score and Function Score were 61+/-17 and 46+/-16 before, and 97+/-5 (P<0.0001) and 91+/-13 (P<0.0001) after surgery at the final follow-up, respectively. The femoro-tibial angle in standing with one leg was 183+/-6 degrees (3 degrees of anatomical varus angulation) before and 170+/-3 degrees (P<0.0001) (10 degrees of anatomical valgus angulation) after surgery., (Copyright 2002 Elsevier Science B.V.)

High tibial osteotomy was performed in 73 knees of 50 patients with medial and patellofemoral compartmental osteoarthritis of the knee, which was combined with anterior advancement of the distal fragment. At the operation, parapatellar release of the retinaculum and subperiosteal elevation of contracted medial soft tissue were also adjoined. The average age of the patients at the time of surgery was 64 years. The follow-up period was an average of 58 months. On overall clinical results assessed with the Knee Society score, the average total knee score was improved from preoperative 50 points to postoperative 94, and the preoperative average functional score of 47 points increased to 92 postoperatively. At follow-up, pain from a grinding patella was not found in 68 of 73 knees and pain from grinding and deviating of the patella was relieved in more than 96% of all cases. The mean femorotibial angle was reduced from preoperative 185 degrees to postoperative 167 degrees. On skyline view, the width of the lateral facet joint space was widely opened postoperatively, particularly on the flexion angle of 90 degrees. This operative procedure successfully relieved patellofemoral symptoms of the patients with medial and patellofemoral compartmental osteoarthritis of the knee.

A porous hydroxyapatite (highly purified synthetic Ca10(PO4)6(OH)2) wedge was inserted into the tibia in 10 knees of 7 patients with osteoarthritis of the knee who underwent high tibial osteotomy. The interface of this HA wedge with bone was histologically examined in undecalcified specimens obtained at the time of hardware removal in all 10 knees, and total incorporation of the HA into bone was observed, with no inflammatory reaction. The proportion of pores that were filled with regenerated bone within 300 microm from the interface was 71.8 +/- 10.1% (mean +/- S.D.), and it was positively correlated with the time from implantation to biopsy. Radiodensity of the HA wedge was measured during the follow-up period, and it did not change significantly within 36 months after osteotomy. Our study concluded that bone ingrowth into the HA block slowly progressed and was correlated with the passage of time.

The synovium of the osteoarthritic knee was investigated for pathological changes after high tibial osteotomy (HTO) in a prospective two-year follow-up study. The series included 11 osteoarthritic knees in 9 patients with a mean age of 57 +/- 8 years (range: 47 to 70 years). Synovial specimens were obtained from the medial part of the knee just above the medial meniscus at the time of HTO, and taken from a different medial portion from the initial biopsy at the time of removal of the internal fixation (mean interval: 21 +/- 4 months). Lining cell hyperplasia, villous hypertrophy, cell infiltration, and vascular proliferation, observed in the first biopsy specimens, were less discernible in the samples from the second biopsy, which were obtained at the time of the removal of the fixation device. Immunohistochemical staining of the specimens revealed that cartilage fragments positive for type 2 collagen were surrounded by proliferating lining cells at the time of osteotomy. These lining cells were predominantly stained with anti-CD68 antibody for macrophage lineage cells. The mean numbers of type 2 collagen-positive fragments and CD68-positive cells in the lining layer at HTO were 9.1 +/- 6.2 (3 to 26) and 30.8 +/- 11.0 (17 to 55) per high power field (x400), respectively, while they were 1.1 +/- 1.2 (0 to 4) (p < 0.005) and 14.8 +/- 4.7 (7 to 21) (p < 0.01), respectively, at the time of removal. The number of these cartilage fragments decreased markedly after correction of the varus deformity by HTO. In conclusion, the excessive pressure on the medial compartment of the osteoarthritic knee with a varus deformity can cause wearing of the articular cartilage and fragmentation. The cartilage fragments might stimulate macrophage lineage cells in the lining layer and might cause synovitis in osteoarthritis. After correction of the varus deformity by HTO, the synovitis subsided because there were fewer cartilage fragments and less wear.

The change of patellar height after the displacement of tibial tuberosity and its effect on the improvement of clinical signs of knees was studied. The anterior displacement of tibial tuberosity was performed on fourteen knees and the anteromedial displacement on twenty knees with patellofemoral arthrosis of twenty-nine patients, four men and twenty-five women with the age at operation ranging from 47 to 79 years (average: 58.3). The anteromedial displacement of tibial tuberosity was performed on ten knees and medial displacement on fifteen knees with recurrent patellar dislocation (eleven knees) or patellar subluxation (fourteen knees) of twenty-four patients, two men and women with the an age range from 14 to 37, (average: 22.4). Patellar height was measured on lateral view by the Insall-Salvati method using Ligament/Patella ratio (Lt/Lp ratio). Ligament/Patella ratio of the older group with patellofemoral arthrosis was decreased significantly (p < 0.01) after surgery, from 1.10 to 0.94. The ratio of the younger group with patellar dislocation or subluxation showed no significant changes, but of seven knees with high riding patella, which ratio revealed more than 1.2 before operation, decreased significantly (p < 0.001) from 1.47 to 1.31. The postoperative patella baja had no poor effect on the improvement of clinical signs.

One hundred and eight osteoarthritic knees that had high tibial osteotomy were examined, in the length of the patellar ligament, patellar height, and the strength of the quadriceps muscle. Patellar ligament shortening occurred until one year after surgery. Subsequently, shortening was not observed to be significant over a 10 year followup period. Using Insall-Salvati ratio, a majority of knees seemed to have lower patellae, because of the shortening of the patellar ligament. However, using patellotibial distance, 68 percent of patellae maintained the same height as preoperatively and 26 percent became patella baja. The strength of the quadriceps muscle increased postoperatively, reached the maximum at 2 years, and preserved the same strength over 10 years. Patellar ligament shortening and patella baja were probably thought to be caused by the biological adaptation of the extensor mechanism and the shrinking of the scar tissue in and around the postoperative patellar ligament.

High tibial osteotomies were performed on 136 osteoarthritic knees for correction of varus deformity. Before osteotomy all patients experienced moderate or severe pain, and the knees showed lateral thrust on weight-bearing. The patients were followed up for one to five years. Marked relief of pain was obtained in 112 knees, and the patients were satisfied with the result of operation in 122. These painless knees showed no lateral thrust, and in the majority the deformity had been adequately corrected, with post-operative femoro-tibial angles (standing) ranging from 165 degrees to 174 degrees. Four of 28 knees with femoro-tibial angles of 175 degrees to 179 degrees, when measured one year after operation, showed recurrence of varus deformity three years after osteotomy. Preoperative ranges of knee motion were well maintained after osteotomy even when arthrotomy had also been undertaken. Intra-articular assessment in two patients, several years after operation, showed that the most degenerated portions of the articular surface were completely covered by a fibrocartilagenous layer, with no bare bone. High tibial osteotomy is most effective in osteoarthritic knees with varus deformity, when correction is made to a femoro-tibial angle (standing) of 170 degrees (10 degrees valgus).

Surgical techniques were described on tibial osteotomy above the tuberosity, the fragments of which were fixed with a Koshino blade plate. Postoperative clinical results on 176 knees with medial compartment osteoarthritis of 138 patients with an average age of 62.1 years were excellent in 110 and good in 55 knees with an average of 5.5 years' follow-up. The best knee score was obtained in the knee with postoperative limb alignment of 6 to 15 degree valgus angulation (standing). The results were satisfactory, especially in postoperative management, which was much easier with the Koshino blade plate fixation than with other methods. The sinking of the osteotomy site was checked through observation of screw movement in the slot of the plate during postoperative management in 53 selected knees, and the averaged distance of sinking was 3.9 +/- 2.5 mm. The time of mechanical bone union judged by cessation of sinking averaged 12.9 +/- 6.2 weeks after osteotomy.

High tibial osteotomy to correct a varus or valgus deformity was performed on thirty-seven knees (thirty-six patients) with spontaneous osteonecrosis of the femoral condyle (thirty-five medial and two lateral). Drilling or bone-grafting of the necrotic lesion was done concomitantly with the osteotomy in twenty-three knees. Follow-up periods ranged from two years to eight years and six months. Preoperative pain was relieved and walking ability was improved in thirty-five knees. The clinical results, as rated by a knee score, were better in those knees with osteonecrosis of the medial femoral condyle and a postoperative femorotibial angle (as measured on a standing roentgenogram) ranging from 164 to 173 degrees (7 to 16 degrees of valgus angulation). Postoperatively in seventeen knees. Roentgenographic improvement was greater in those knees in which tibial osteotomy was performed concomitantly with bone-grafting or drilling. Postoperative arthrotomy in eight knees showed that the necrotic lesion was covered with a white layer of fibrocartilage in three of the four knees that had had osteotomy more than one and one-half years previously.

Bowlegs in childhood were emphasized as one of the most important etiological factors in medial compartmental osteoarthritis of the knee (knee OA). A long-term follow-up study was performed on 75 knees of 53 patients after high tibial valgus osteotomy for knee OA. There were 15 knees in 11 men and 60 knees in 43 women. The follow-up period ranged from 15 to 28 years with a mean of 19±3 years. The age at osteotomy ranged from 46 to 73 years with a mean of 59.6±6.7 years. Valgus osteotomy closing wedge was performed in all cases, aiming for an anatomical valgus angulation of 10°(standing). The American Knee Society Score showed a Knee Score of 37±20 and a Function Score of 38±16 preoperatively and 87±13 and 80±19 at the final 15 to 28 years follow-up. The repair of articular cartilage after high tibial valgus osteotomy was observed in 146 knees of 115 patients. The mean age of the patients at osteotomy was 65±7 years(range 47∼80). Observations were made through an arthrotomy at the time of removal of the blade plate, an average of 2 years after the initial osteotomy. Regeneration of the degenerated cartilage was classified into three stages. There were no regenerative findings (Stage A)in 13 knees; partial regeneration with fibrocartilaginous tissue (Stage B) in the previous degenerated area in 86 knees; and total coverage by new regenerated fibrocartilage containing hyaline-like cartilage (Stage C) in 47 knees (Stage B and Stage C 91%). As for floor sitting, recent follow-up results after high tibial osteotomy on knee range of motion showed that 24 knees (77%) were able to sit on the floor, among the 31 knees which showed no sitting on floor and had 137° ± 12° arc of motion before surgery. Unicompartmental knee arthroplasty for medical and medialization of the tibial tuberosity and for patellofemoral compartmental knee OA were added, respectively. [ABSTRACT FROM AUTHOR]