Abstract
Varus knees with associated cartilage pathologies are not uncommon scenarios that present to orthopaedic surgeons.
There is no agreement on the ideal management of varus knees with concomitant cartilage pathology.
Through a literature review, the authors tried to answer three main questions:
On October 2022, OVID MEDLINE, EMBASE, and COCHRANE databases were searched. Clinical studies reporting on clinical, radiologic, or macroscopic cartilage regeneration following either isolated knee osteotomy or concomitant osteotomy and a cartilage procedure were reviewed.
Despite controversies, the literature demonstrated favourable outcomes of combined knee osteotomy and a cartilage procedure in patients with substantial deformity and cartilage defects.
Isolated high tibial osteotomy may induce cartilage regeneration in several scenarios and severities of concomitant malalignment and cartilage defects.
There are recommendations that knee osteotomy should be added to a cartilage procedure when an extra-articular deformity of > 5° is detected.
Some studies report good outcomes for combining a knee osteotomy with cartilage grafting, but they lack a control group of isolated osteotomy.
There is still scarce of evidence on the influence of osteotomies on cartilage regeneration and the outcomes of concomitant osteotomy and different cartilage procedures vs isolated osteotomies.
With advanced statistical evaluation (artificial intelligence, machine learning) of big datasets, more answers and better results will be delivered.
Introduction
Young active patients with symptomatic chondral defects or arthritic changes and varus knee malignment pose challenging scenarios to knee surgeons (1). There are needs for an agreement on the ideal management option for these cases (2). Isolated high tibial osteotomy yields good midterm results but demonstrates clinical and radiographic deterioration in the long term (3, 4, 5).
Cartilage treatment procedures have reported good outcomes. However, the presence of lower limb malalignment can threaten the success of these procedures with consequent failures (6, 7, 8). Hence, knee osteotomy is becoming more popular as an additional procedure with cartilage repair surgeries in cases of malalignment to improve the long-term outcomes.
The superior clinical outcomes of performing a knee osteotomy concomitantly with cartilage procedures still need to be fully validated (9). This review presents a wide array of the most recent studies that have evaluated cartilage regeneration in multiple domains following knee osteotomy, either isolated or combined with various cartilage restorative procedures.
Methods
On the 3 October 2022, a systematic search of the following databases OVID MEDLINE, EMBASE, and Cochrane Databases was conducted. Clinical studies of any level of evidence were reviewed. The study excluded animal or biomechanical studies, case reports, review papers, study protocols, editorial commentaries, conference papers, and papers not written in English.
Review and discussion
Is an isolated knee osteotomy sufficient to treat patients with extra-articular deformity and cartilage defects, and will the cartilage regrow afterwards?
Several authors have reported better macroscopic cartilage regeneration and improved clinical outcomes following isolated single- or double-level knee osteotomies for patients with variable cartilage defects and extraarticular deformities (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24). More recently, Kim et al. 2022 (14) evaluated cartilage regeneration following medial opening wedge high tibial osteotomy (MOWHTO) for medial compartment osteoarthritis (OA) with or without radiographic kissing lesions (RKL). RKL was denoted as definite bone-to-bone contact between the medial femoral condyle (MFC) and medial tibial plateau (MTP) on preoperative standing anteroposterior and lateral or Rosenberg view radiographs. The included patients had varus malalignment of > 5° and OA Kellgren-Lawrence (KL) grades II−IV. The mean preoperative to postoperative correction degrees of the hip−knee−ankle angles were 0.9 ± 3.6° and 1.0 ± 3.2 ° in the RKL and No-RKL groups, respectively. Arthroscopic assessment of the medial compartment cartilage status was recorded at the first and second stages of arthroscopy, before and after MOWHTO, according to the International Cartilage Regeneration and Joint Preservation Society grade (ICRS) (25). ICRS grade 1 involved superficial lesions and superficial fissures and cracks, grade 2 involved cartilage defects with an extension to <50% of the cartilage depth, grade 3 involved lesions with an extension to >50% of the cartilage depth with no subchondral bone involvement, and grade 4 comprised defects involving the subchondral bone. Two years after MOWHTO, cartilage regeneration was macroscopically evaluated based on the macroscopic staging system by Koshino et al. (15): stage A, no regeneration; stage B, partial regeneration (such as pink fibrous tissue with or without partial coverage with white fibrocartilage); and stage C, total regeneration. Cartilage regeneration was demonstrated in the MFCs in 83% and 79%, and in the MTPs in 64.7% and 49% in the RKL and no-RKL patients, respectively. At a mean follow-up of 7.5 (5−12.8) years, all patients had significant clinical improvement as reflected by American Knee Society (AKS) knee and function scores >80, with no differences between both groups in preoperative-to-postoperative scores. Additionally, there were no in-between group differences in the postoperative grade of cartilage regeneration or changes in radiological alignment parameters. An overall HTO survival rate (No MOWHTO revision or TKA conversion) of 100% and 97.1% were reported in the RKL and no-RKL groups, respectively (P ≥ 0.999). Nakayama et al. 2021 (18) in a series of double level knee osteotomy (DLO) for severe varus deformity (≥10°) and advanced OA, assessed the status of the medial compartment articular cartilage preoperatively by MRI examination, and arthroscopic grading based on ICRS grading (25). Postoperatively, at a mean of 17.1 ± 5.0 (12-33) months, the mean mechanical tibiofemoral angle (mTFA) was corrected from 13.7 ± 3.0 varus to 0.8 ± 2.6 varus (virtually neutral alignment). At the postoperative stage, cartilage repair was evaluated as per Koshino et al. (15) and demonstrated cartilage regeneration (stages B and C) in 95.7% of the MFCs, 97.9% of the MTPs, 85.1% of the femoral trochlea, and 12.8% of the patellar facets. Additionally, significant clinical improvement was reported as reflected by improved Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee Subjective Knee Form (IKDC) subjective scores (P < 0.01). Akamatsu et al. 2021 (11) evaluated cartilage regeneration following (OWHTO) with a correction angle of ≤15° vs closed wedge high tibial osteotomy (CWHTO) with a correction angle of ≥15° in cases with severe medial knee OA. There was a significant clinical improvement after surgery (improved KSS scores P < 0.05) without any significant difference between the two groups. Following OWHTO, partial and complete cartilage regeneration of the MFCs was observed in 66% and 13% of cases, respectively, and was noted to be 71% and 13% following CWHTO, respectively. In the MTPs, following OWHTO, partial and complete cartilage regeneration was observed in 55% and 9%, respectively, and was 58% and 11% following CWHTO. The preoperative ICRS cartilage degeneration grade was the only reported factor that affected cartilage regeneration, with significantly higher cartilage repair in cases with preoperative advanced ICRS grade (P < 0.05). Kim et al. 2020 (13) evaluated cartilage regeneration after HTO for medial knee OA (KL grades II–IV) with 5–15° of varus malalignment. The patients were subdivided into two groups: with or without lateral knee or patellofemoral asymptomatic degenerative changes (KL grade I). At the latest follow-up, there was cartilage regeneration in the medial compartment (improved MRI Osteoarthritis Knee Score (MOAKS) classification systems and ICRS grades) with no significant difference between both groups (P = 0.8 and 0.9, respectively). In the lateral and patellofemoral compartment, cartilage degeneration was reflected by a decline of the MOAKS and ICRS grades with no significant difference between both groups; MOAKS (P = 0.6 and 0.4, respectively) and ICRS grades (25) (P = 0.9 and 0.6, respectively). No radiographic or clinical differences in outcomes were reported between both groups. Ferruzzi et al. 2014 (26) studied a matched cohort of 56 patients with KL grade III/IV OA and an average 8° varus deformity treated with either an isolated MOWHTO, MOWHTO + ACI (autologous chondrocyte implantation), or MOWHTO + Microfracture (MFx). Eight out of 20 in the isolated MOWHTO group and 6 out of 18 patients in the other two groups had previous medial meniscectomy. At an 11-year follow-up, clinical improvements were reported in all treatment groups. Both the isolated MOWHTO and MOWHTO-ACI group demonstrated better HSS (Hospital for Special Surgery) and WOMAC (Western Ontario and McMaster University) scores than the HTO-MFx group; however, this difference was not significant.
The aforementioned studies demonstrated that an isolated knee osteotomy not only corrects malalignment but also can facilitate cartilage regeneration in severe degenerate diseases of the medial compartment and in the presence of mild lateral compartment or patellofemoral asymptomatic degenerative changes, Additionally, an isolated osteotomy can be as effective as a combined osteotomy and a cartilage repair procedure in severe OA grade with varus malalignment, regardless of the meniscus status.
At what severity of varus deformity should a knee osteotomy be considered when cartilage surgery is planned?
Faber et al. 2020 (12), in a German registry study (KnorpelRegister DGOU), looked at 736 patients with MFC cartilage defects. The factors affecting the decision to perform simultaneous HTO with a cartilage repair procedure were assessed. A varus deformity of 3° was the primary determinant of adding HTO to a cartilage repair procedure in most patients. The mean degree of varus in the patients who received additional HTO vs those who received isolated cartilage procedure was 5.61 ± 2.73° vs 1.72 ± 2.38°, P < 0.00. However, among the other factors that differed significantly between the two groups were the lesion size 44.16 ± 22.53 cm2 vs 38.6 5 ± 20.42 cm2, P = 0.001), the lesion grade (62.5% IVa/IVb vs 57.3% IVa/ IVb, P = 0.014), the integrity of the corresponding joint surface (10.8% grades III–IV vs 0.2% grades III–IV, P < 0.001), and the meniscus status (15.5% >1/3 resected vs 4.4% >1/3 resected, P< 0.001). A year later, the same group of authors, Faber et al. 2021 (10), assessed the clinical efficacy of the combined procedures in 440 patients over 3 years of follow-up. The group of patients who had additional HTO procedure had a mean varus of 5.64 ± 2.8°, a mean lesion size of 42.76 ± 21.4 cm2 compared to a mean varus degree of 5.8 ± 3.52° and a mean lesion size of 42.17 ± 24.27 cm2. An additional HTO procedure was reported to significantly improve the clinical outcomes with higher postoperative KOOS scores (12 months: P = 0.001; 24 months: P = 0.01; 36 months: P = 0.02) and reduced pain perception as demonstrated by the VAS (visual analogue scale) scores (6 months: P = 0.009; 12 months: P < 0.001; 24 months: P = 0.005; 36 months: P = 0.003). At 1- and 3-years follow-up, patients with an additional HTO reported significantly higher satisfaction rates. However, this superior outcome was seen only in patients with five or more degrees of varus deformity, in comparison to their counterparts who exhibited increased pain levels during the 3-year follow-up when no additional HTO was performed. Bode et al. 2013 (27) compared a group of patients with a mean varus degree of 3.53 ± 1.09° and a mean lesion size of 4.86 ± 2.98 cm2 who received ACI + HTO to a group of patients with a mean varus degree of 2.25° ± 0.99° and a mean lesion size of 4.40 ± 2.28 cm2 who received isolated ACI. They demonstrated better clinical improvement in the KOOS symptoms for ACI + HTO (P = 0.3) and higher survival rate for combined HTO + ACI group vs the isolated ACI group (89.5% vs 58.33%; respectively P = 0.02). Additional HTO was recommended when performing ACI for cartilage defects with varus malalignment (less or more than 5°) to increase the survival rates and decrease the reintervention rate. Hence, in an attempt to improve clinical outcomes and procedure survival, a knee osteotomy should be added to a planned cartilage procedure when there is a varus malalignment irrespective of the severity of varus deformity; less than, equal or more than 5°.
Should I add an osteotomy to autograft or allograft cartilage procedures?
Some authors reported no difference in clinical outcomes when a knee osteotomy is added to osteochondral autograft transfers (OATs) (Figs. 1, 2, 3, 4, and 5). Mukai et al. 2022 (28) compared OATs + HTO to isolated OATs for knee subchondral insufficiency fractures. The OATS + HTO group had an average lesion size of 44.5 ± 17 cm2, where a coverage ratio of 44.9 ± 14.8% was achieved. On the other hand, the isolated OATs group had an average lesion size of 35.4 ± 10.2 cm2, where a coverage ratio of 48.3 ± 13.5% was achieved. One year postoperatively, all patients improved clinically with Lysholm scores exceeding the minimal clinically important difference (MCID) for isolated OATs (6.6) vs OATs + HTO (8.4). However, when they performed a radiological comparison, concomitant OATs + HTO was found to yield less Bone Marrow Oedema Scores (P = 0.006), better Plug Union Scores (P = 0.02), and less Plug Necrosis Scores (P = 0.03) with significantly lower modified MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) scores, which were not correlated to clinical outcomes.
Preoperative long leg standing radiographs with the osteotomy planned; marked in green is (A) preoperative weight-bearing line (Mikulicz line) intersecting the tibia at Mikulicz point. (B) The planned postoperative weight-bearing line passing 50–55% of the medial tibial plateau and extrapolated to the postoperative ankle centre at the talar dome. (C) The correction angle (Miniaci angle) drawn from the hinge point with two subtending lines; the preoperative and postoperative ankle centres.
Citation: EFORT Open Reviews 9, 3; 10.1530/EOR-23-0180
Preoperative CT scan. (A) and (B) Coronal, (C) sagittal, and (D) axial cuts show medial femoral condyle cartilage defect.
Citation: EFORT Open Reviews 9, 3; 10.1530/EOR-23-0180
Preoperative MRI scan. (A) Coronal. (B) coronal. Show cartilage defect of the medial femoral condyle.
Citation: EFORT Open Reviews 9, 3; 10.1530/EOR-23-0180
Shows the intraoperative steps for OATs (osteochondral autograft transfers) of the medial femoral condyle. (A) Donor site near the trochlea after a cylindrical graft extracted. (B) Implantation of the autograft cylinder at the medial femoral condyle defect. (C) Medial femoral condyle with the implanted osteochondral autograft cylinder.
Citation: EFORT Open Reviews 9, 3; 10.1530/EOR-23-0180
Postoperative anteroposterior radiograph shows the correction performed and the osteotomy fixed with a locking plate, and OATs of the medial femoral condyle.
Citation: EFORT Open Reviews 9, 3; 10.1530/EOR-23-0180
On the other hand, other authors were proponents of combining HTO with cartilage grafts. Minzlaff et al. 2013 (29) in a series of patients with a mean preoperative varus degree of 4.7 ± 2.1° and a mean defect size measured intraoperatively of 2.15 ± 0.93 cm in diameter (range, 0.8−5.5 cm) reported significant clinical improvement following combined HTO and OATs. However, 13% failure rate at 5 years follow-up was reported. These failures occurred in patients with a mean varus deviation of 6.6 ± 2.4° (4.0–10°) and with a mean defect size of 2.82 ± 1.86 cm2 in diameter. They reported a statistically significant risk increment for failure associated with a higher degree of axis correction (Δ varus preoperative – valgus postoperative). Kim et al. 2019 (30) recommended for HTO with concomitant cartilage procedure to correct the mechanical axis to neutral or less than 3° of valgus as an effective and safe method to achieve the desired outcomes with no complications. Kumagai et al. 2018 (31) compared OWHTO + OATs vs OWHTO + bone marrow stimulation (BMS) in patients with spontaneous osteonecrosis of the knee (SONK) of the MFC. The mean femorotibial angle has improved in the OATs and BMS groups from preoperative mean varus of 181.1°, and 180.7° to postoperative mean valgus of 169.6° and 169.7°, respectively. The mean lesion size was 4.4 cm2 in the patients who received OATs vs 2.9 cm2 in the patients who received BMS. At 2 years of follow-up, significant clinical improvement was noted with no significant differences between groups (improved KSS objective score and function score). However, macroscopically, the OATs group outperformed the BMS group with significantly better cartilage repair. Almost 90% of the OATs group had normal or near normal cartilage status (ICRS overall score ≥8) irrespective of the lesion size, in comparison with only 41% in the BMS group where all patients had a lesion size <4 cm2 (P = 0.0015). The same author, Kumagai et al. 2022 (32), evaluated HTO + OATs for SONK of the MFC with varus knee ≤5° and larger lesions size ≥4 cm2. At the 5-year follow-up, they reported significant clinical improvements (increased KSS objective and function scores P < 0.05) along with substantial radiographic correction of the femorotibial angle (P < 0.05) regardless of the age group (younger or older than 70 years). Good durability with a 100% survival rate of the combination (HTO + OATs) was reported throughout the follow-up period (none of the patients had any revision surgery).
Aubin et al. 2001 (33) assessed the consequences of fresh femoral osteochondral allograft (OCA) for distal femur chondral defects in 72 patients. Realignment was required in 41 patients (68%) with a high tibial osteotomy done in 25 (61%) and a distal femoral varus osteotomy done in 16 (39%). The graft survival rate was 85% at 10 years and 74% at 15 years. All patients clinically showed improvement in the HSS scores of 83 points regardless of OCA site – medial or lateral femoral condyles, and whether it was an isolated procedure or combined with HTO. Their conclusion demonstrated highlighted the success of this practice where patients required knee osteotomy with OCA had equal outcomes to those patients who had OCAs and did not need knee osteotomy. And more recently, Zitsch et al. 2021 (7) investigated the outcomes of OCA with simultaneous or staged realignment osteotomy (DFO and HTO) in patients with bipolar articular cartilage lesions. At 2 years of follow-up, all patients had improved clinically with improved patient-reported outcome measures (PROMs). However, the simultaneous osteotomies outperformed the staged ones in almost all PROMs. Simultaneous osteotomies and OCA resulted in significant pain reduction with lower pain scores at 12 months compared to staged osteotomies and OCA (P = 0.04). Overall, successful outcomes were reported in 70% of patients, TKA conversion in 13% and revision OCA transplantation in 17.4%. The 2-year functional survival rate was 87.4%. Leon et al. 2019 (6) evaluated the clinical outcomes and survival of concomitant knee osteotomy and unipolar fresh OCA. The mean lesion diameter was 2.54 cm (1–5.55 cm) and concomitant realignment osteotomy (HTO or DFO) with 2°–3° of overcorrection was performed when the preoperative mechanical axis passes through the affected compartment. There were significant clinical improvements at a mean of 11.4 years follow-up (improved modified HSS scores). They reported a 43.3% reoperation rate and 38.3% overall complications with persistent postoperative malalignment more frequently observed in cases of graft failure (28.6% vs 4.3%; P = 0.02). At a mean of 8.6 years, 14 grafts (23.3%) required TKA conversion. Persistent postoperative malalignment was a risk factor for graft failure (hazard ratio 6.55; P = 0.009). Graft survivorship was reported to be 87.3%, 85%, 74.8%, 65.2%, and 59.8% at 5, 10, 15, 20, and 25 years, respectively. Ackermann et al. 2020 (34) selectively advocated realignment osteotomy to neutral in conjunction with ACI and not with OCA. In their series, valgus alignment was a significant factor for ACI failure (P = 0.002), There were no significant differences in OCA survivorship relative to the mechanical axis alignment (P > 0.05) despite a trend towards improved survivorship with neutral alignment.
Based on the presented studies, it seems that concomitant knee osteotomies and OATs or OCA could improve the clinical outcomes and the survivorship of the cartilage procedure. However, mechanical axis overcorrection should be avoided.
Based on the presented review and the practice of the senior author, the authors proposed the following algorithm for the management of patients presenting with chronic knee pain due to extra-articular varus deformity and or cartilage lesion (Fig. 6).
An algorithm for management of chronic knee pain due to extra-articular deformity and/or cartilage lesion.
Citation: EFORT Open Reviews 9, 3; 10.1530/EOR-23-0180
Conclusion
Isolated knee osteotomies can be sufficient to treat patients with extra-articular deformities and cartilage defects and cartilage will regrow. Knee osteotomy should be added to a planned cartilage procedure in the presence of varus malalignment regardless of the severity of the deformity. Additional knee osteotomy can improve the outcomes and survivorship of osteochondral autograft transfers and osteochondral allografts when realignment is required.
ICMJE Conflict of Interest Statement
The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the work reported here.
Funding Statement
This study did not receive any specific grant from any funding agency in the public, commercial, or not-for-profit sector.
References
- 1↑
Sterett WI, Steadman JR, Huang MJ, Matheny LM, & Briggs KK. Chondral resurfacing and high tibial osteotomy in the varus knee: survivorship analysis. American Journal of Sports Medicine 2010 38 1420–1424. (https://doi.org/10.1177/0363546509360403)
- 2↑
Franceschi F, Longo UG, Ruzzini L, Marinozzi A, Maffulli N, & Denaro V. Simultaneous arthroscopic implantation of autologous chondrocytes and high tibial osteotomy for tibial chondral defects in the varus knee. Knee 2008 15 309–313. (https://doi.org/10.1016/j.knee.2008.04.007)
- 3↑
Akizuki S, Shibakawa A, Takizawa T, Yamazaki I, & Horiuchi H. The long-term outcome of high tibial osteotomy: a ten- to 20-year follow-up. Journal of Bone and Joint Surgery. British Volume 2008 90 592–596. (https://doi.org/10.1302/0301-620X.90B5.20386)
- 4↑
Koshino T, Yoshida T, Ara Y, Saito I, & Saito T. Fifteen to twenty-eight years’ follow-up results of high tibial valgus osteotomy for osteoarthritic knee. Knee 2004 11 439–444. (https://doi.org/10.1016/j.knee.2004.03.005)
- 5↑
Lau LCM, Fan JCH, Chung KY, Cheung KW, Man GCW, Hung YW, Kwok CKB, Ho KKW, Chiu KH, & Yung PSH. Satisfactory long-term survival, functional and radiological outcomes of open-wedge high tibial osteotomy for managing knee osteoarthritis: minimum 10-year follow-up study. Journal of Orthopaedic Translation 2021 26 60–66. (https://doi.org/10.1016/j.jot.2020.03.003)
- 6↑
León SA, Mei XY, Safir OA, Gross AE, & Kuzyk PR. Long-term results of fresh osteochondral allografts and realignment osteotomy for cartilage repair in the knee. Bone and Joint Journal 2019 101–B 46–52. (https://doi.org/10.1302/0301-620X.101B1.BJJ-2018-0407.R1)
- 7↑
Zitsch BP, Stannard JP, Worley JR, Cook JL, & Leary EV. Patient-reported outcomes for large bipolar osteochondral allograft transplantation in combination with realignment osteotomies for the knee. Journal of Knee Surgery 2021 34 1260–1266. (https://doi.org/10.1055/s-0040-1710361)
- 8↑
Krych AJ, Hevesi M, Desai VS, Camp CL, Stuart MJ, & Saris DBF. Learning from failure in cartilage repair surgery: an analysis of the mode of failure of primary procedures in consecutive cases at a tertiary referral center. Orthopaedic Journal of Sports Medicine 2018 6 2325967118773041. (https://doi.org/10.1177/2325967118773041)
- 9↑
Lee OS, Ahn S, Ahn JH, Teo SH, & Lee YS. Effectiveness of concurrent procedures during high tibial osteotomy for medial compartment osteoarthritis: a systematic review and meta-analysis. Archives of Orthopaedic and Trauma Surgery 2018 138 227–236. (https://doi.org/10.1007/s00402-017-2826-4)
- 10↑
Faber S, Angele P, Zellner J, Bode G, Hochrein A, & Niemeyer P. Comparison of Clinical Outcome following Cartilage Repair for Patients with Underlying Varus Deformity with or without Additional High Tibial Osteotomy: a Propensity Score-Matched Study Based on the German Cartilage Registry (KnorpelRegister DGOU). Cartilage 2021 13(1_suppl) 1206S–1216S. (https://doi.org/10.1177/1947603520982347)
- 11↑
Akamatsu T, Kumagai K, Yamada S, Nejima S, Sotozawa M, Ogino T, & Inaba Y. No differences in clinical outcomes and cartilage repair between opening wedge and closed wedge high tibial osteotomies at short-term follow-up: a retrospective case series analysis. Journal of Orthopaedic Surgery 2021 29 23094990211020366. (https://doi.org/10.1177/23094990211020366)
- 12↑
Faber S, Zellner J, Angele P, Spahn G, Löer I, Zinser W, & Niemeyer P. Decision making for concomitant high tibial osteotomy (HTO) in cartilage repair patients based on a nationwide cohort study of 4968 patients. Archives of Orthopaedic and Trauma Surgery 2020 140 1437–1444. (https://doi.org/10.1007/s00402-020-03476-6)
- 13↑
Kim DH, Kim SC, Yoon JS, & Lee YS. Are there harmful effects of preoperative mild lateral or patellofemoral degeneration on the outcomes of open wedge high tibial osteotomy for medial compartmental osteoarthritis? Orthopaedic Journal of Sports Medicine 2020 8 2325967120927481. (https://doi.org/10.1177/2325967120927481)
- 14↑
Kim KI, Kim JH, Lee SH, Song SJ, & Jo MG. Mid- to long-term outcomes after medial open-wedge high tibial osteotomy in patients with radiological kissing lesion. Orthopaedic Journal of Sports Medicine 2022 10 23259671221101875. (https://doi.org/10.1177/23259671221101875)
- 15↑
Koshino T, Wada S, Ara Y, & Saito T. Regeneration of degenerated articular cartilage after high tibial valgus osteotomy for medial compartmental osteoarthritis of the knee. Knee 2003 10 229–236. (https://doi.org/10.1016/s0968-0160(0300005-x)
- 16↑
Moon HS, Choi CH, Jung M, Park SH, Lee DY, Shin JC, & Kim SH. The effect of cartilage lesion in the lateral compartment of the knee on the surgical outcome of medial open-wedge high tibial osteotomy. Journal of Knee Surgery 2021 34 538–545. (https://doi.org/10.1055/s-0039-1697623)
- 17↑
Moon HS, Choi CH, Yoo JH, Jung M, Lee TH, Byun JW, & Kim SH. An increase in medial joint space width after medial open-wedge high tibial osteotomy is associated with an increase in the postoperative weight-bearing line ratio rather than with cartilage regeneration: comparative analysis of patients who underwent second-look arthroscopic assessment. Arthroscopy 2021 37 657–668.e4. (https://doi.org/10.1016/j.arthro.2020.09.042)
- 18↑
Nakayama H, Kanto R, Onishi S, Kambara S, Ukon R, Amai K, Yoshiya S, Schröter S, Tachibana T, & Iseki T. Cartilage repair examined by second-look arthroscopy following double-level osteotomy performed for osteoarthritic knees with severe varus deformity. Knee 2021 29 411–417. (https://doi.org/10.1016/j.knee.2021.02.024)
- 19↑
Odenbring S, Egund N, Lindstrand A, Lohmander LS, & Willén H. Cartilage regeneration after proximal tibial osteotomy for medial gonarthrosis. An arthroscopic, roentgenographic, and histologic study. Clinical Orthopaedics and Related Research 1992 277 210–216.
- 20↑
Parker DA, Beatty KT, Giuffre B, Scholes CJ, & Coolican MRJ. Articular cartilage changes in patients with osteoarthritis after osteotomy. American Journal of Sports Medicine 2011 39 1039–1045. (https://doi.org/10.1177/0363546510392702)
- 21↑
Schultz W, & Göbel D. Articular cartilage regeneration of the knee joint after proximal tibial valgus osteotomy: a prospective study of different intra- and extra-articular operative techniques. Knee Surgery, Sports Traumatology, Arthroscopy 1999 7 29–36. (https://doi.org/10.1007/s001670050117)
- 22↑
Wakabayashi S, Akizuki S, Takizawa T, & Yasukawa Y. A comparison of the healing potential of fibrillated cartilage versus eburnated bone in osteoarthritic knees after high tibial osteotomy: an arthroscopic study with 1-year follow-up. Arthroscopy 2002 18 272–278. (https://doi.org/10.1053/jars.2002.30488)
- 23↑
Yang HY, Kwak WK, Kang SJ, Song EK, & Seon JK. Second-look arthroscopic cartilage status is related to intermediate-term outcomes after medial opening-wedge high tibial osteotomy. Bone and Joint Journal 2021 103–B 1686–1694. (https://doi.org/10.1302/0301-620X.103B11.BJJ-2020-2130.R2)
- 24↑
Okahashi K, Fujisawa Y, Sugimoto K, & Tanaka Y. Cartilage regeneration of Knee OA After High tibial osteotomy. Techniques in Knee Surgery 2010 9 95–100. (https://doi.org/10.1097/BTK.0b013e3181e0a0b0)
- 25↑
Mainil-Varlet P, Aigner T, Brittberg M, Bullough P, Hollander A, Hunziker E, et al.Histological assessment of cartilage repair: a report by the Histology Endpoint Committee of the International Cartilage Repair Society (ICRS). Journal of Bone and Joint Surgery 2003 85-A(Supplement 2) 45–57.
- 26↑
Ferruzzi A, Buda R, Cavallo M, Timoncini A, Natali S, & Giannini S. Cartilage repair procedures associated with high tibial osteotomy in varus knees: clinical results at 11 years’ follow-up. Knee 2014 21 445–450. (https://doi.org/10.1016/j.knee.2013.11.013)
- 27↑
Bode G, Schmal H, Pestka JM, Ogon P, Südkamp NP, & Niemeyer P. A non-randomized controlled clinical trial on autologous chondrocyte implantation (ACI) in cartilage defects of the medial femoral condyle with or without high tibial osteotomy in patients with varus deformity of less than 5°. Archives of Orthopaedic and Trauma Surgery 2013 133 43–49. (https://doi.org/10.1007/s00402-012-1637-x)
- 28↑
Mukai S, Nakagawa Y, Nishitani K, Sakai S, Nakamura R, & Takahashi M. Mosaicplasty with high tibial osteotomy for knee subchondral insufficiency fracture had better magnetic resonance observation of cartilage repair tissue scores with less bone marrow edema and better plug union and less plug necrosis compared to mosaicplasty alone. Arthroscopy 2023 39 337–346. (https://doi.org/10.1016/j.arthro.2022.07.020)
- 29↑
Minzlaff P, Feucht MJ, Saier T, Schuster T, Braun S, Imhoff AB, & Hinterwimmer S. Osteochondral autologous transfer combined with valgus high tibial osteotomy: long-term results and survivorship analysis. American Journal of Sports Medicine 2013 41 2325–2332. (https://doi.org/10.1177/0363546513496624)
- 30↑
Kim MK, Ko BS, & Park JH. The proper correction of the mechanical axis in high tibial osteotomy with concomitant cartilage procedures-a retrospective comparative study. Journal of Orthopaedic Surgery and Research 2019 14 281. (https://doi.org/10.1186/s13018-019-1333-4)
- 31↑
Kumagai K, Akamatsu Y, Kobayashi H, Kusayama Y, & Saito T. Mosaic osteochondral autograft transplantation versus bone marrow stimulation technique as a concomitant procedure with opening-wedge high tibial osteotomy for spontaneous osteonecrosis of the medial femoral condyle. Arthroscopy 2018 34 233–240. (https://doi.org/10.1016/j.arthro.2017.08.244)
- 32↑
Kumagai K, Yamada S, Nejima S, Sotozawa M, & Inaba Y. Minimum 5-year outcomes of osteochondral autograft transplantation with a concomitant high tibial osteotomy for spontaneous osteonecrosis of the knee with a large lesion. Cartilage 2022 13 19476035221126341. (https://doi.org/10.1177/19476035221126341)
- 33↑
Aubin PP, Cheah HK, Davis AM, & Gross AE. Long-term followup of fresh femoral osteochondral allografts for posttraumatic knee defects. Clinical Orthopaedics and Related Research 2001 391 S318–S327. (https://doi.org/10.1097/00003086-200110001-00029)
- 34↑
Ackermann J, Merkely G, Arango D, Mestriner AB, & Gomoll AH. The effect of mechanical leg alignment on cartilage restoration with and without concomitant high tibial osteotomy. Arthroscopy 2020 36 2204–2214. (https://doi.org/10.1016/j.arthro.2020.04.019)
