Changes in clinical outcomes and alignment of the ipsilateral knee and ankle after supramalleolar osteotomy in patients with varus osteoarthritis of the ankle: a short-term follow-up study.

PURPOSE: The purpose of this study was to investigate the changes in clinical outcomes and alignment of the ipsilateral knee and ankle in patients with varus ankle osteoarthritis after supramalleolar osteotomy (SMO). METHODS: We retrospectively reviewed 23 patients (24 ankles) with Takakura II, IIIa and IIIb ankle osteoarthritis treated with SMO between May 2017 and March 2022. The radiologic parameters of ankles contained medial distal tibial angle (TAS), tibiotalar angle (TT), tibial lateral surface (TLS), tibial plafond inclination (TPI) and talar inclination (TI). The radiologic parameters of knees contained medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), the knee joint line orientation relative to ground (G-KJLO) and WBL. Hip-knee-ankle angle (HKA) was also collected. The Takakura system was used for evaluating the ankle osteoarthritis and the Kellgren-Lawrence (KL) system was used for evaluating the knee osteoarthritis. Clinical evaluation of the ankle joints contained American Orthopedic Foot and Ankle Society (AOFAS), range of motion (ROM) and visual analogue scale (VAS). Clinical evaluation of the knee joints contained Japanese Orthopaedic Association Scores (JOA), ROM, VAS. RESULTS: The mean follow-up times were 20.3 ± 7.3 months (range 12-38). According to the radiologic evaluation, the TAS increased from preoperative 84.7° ± 2.0° to 91.2° ± 1.8° at the last follow-up (P < 0.001). The TPI and TI decreased from 4.4° ± 4.2° and 11.0° ± 5.2° to 0.1° ± 4.7° and 4.1° ± 4.8° (P < 0.001 for both). The TT angel improved from 9.5° ± 4.1° to 4.9° ± 3.3° (P < 0.001). No significant differences were found regarding MPTA, JLCA, G-KJLO, knee WBL and HKA (P > 0.05 for all). The Takakura stage improved after SMO (P < 0.001) whilst the KL stage maintains the similar lever (P > 0.05). According to the clinical evaluation, the AOFAS significantly increased from 67.5 ± 10.6 to 88.5 ± 9.3 and the VAS of the ankle decreased from 4.7 ± 1.6 to 1.2 ± 1.1, whilst there were no changes on VAS and even the JOA and knee ROM after SMO (P > 0.05 for all). CONCLUSIONS: SMO can alleviate the symptoms of varus ankle osteoarthritis and delay the time for ankle replacement or arthrodesis by redistributing the abnormal stress of the ankle and restoring the congruence of the tibiotalar joint. In addition, it did not induce the clinical symptoms of knee without compromising lower limb alignment or knee joint line orientation in the short term. LEVEL OF EVIDENCE: Level IV case series.

Effect of total ankle replacement on the 3-dimensional subtalar joint alignment in varus ankle osteoarthritis.

BACKGROUND: Varus ankle osteoarthritis (OA) is typically associated with peritalar instability, which may result in altered subtalar joint position. This study aimed to determine the extent to which total ankle replacement (TAR) in varus ankle OA can restore the subtalar alignment. METHODS: Fourteen patients (15 ankles, mean age 61 ± 6 years) who underwent TAR for varus ankle OA were analyzed using semi-automated measurements based on weight-bearing computed tomography. Twenty healthy individuals served as a control group. RESULTS: All angles improved between preoperative and a minimum of 1 year (mean 2.1 years) postoperative and were statistically significant in 6 out of 8 angles (P < 0.05). CONCLUSIONS: Our findings indicate that talus repositioning after TAR restores the subtalar joint alignment which may improve hindfoot biomechanics. Future studies are required to implement these findings for TAR in presence of hindfoot deformity. LEVEL OF EVIDENCE: IV.

Plain Radiographs Underestimate Varus Deformity of the Tibial Plafond.

Understanding plain radiograph in association with 3-dimensional (3D) morphology of the ankle is essential for treatment about varus ankle osteoarthritis (OA). The aims of this study were to investigate whether the alignment of the tibial plafond as determined on plain radiograph reflected the alignment of the tibial plafond on computed tomography (CT) in varus ankle OA and whether the alignment of the tibial plafond changed as the OA progressed. The 3D CT and plain radiographs from 101 ankles with varus ankle OA were analyzed and compared with 40 ankles in control group. The tibial plafond was assessed in the coronal and sagittal planes using 3D CT. The medial angle between the vertical line and the tibial plafond was measured on 3 different coronal plane CT images which was anterior, middle and posterior area of the tibial plafond. The medial distal tibial angle on plain radiograph reflected the posterior area of the tibial plafond on CT. The amount of varus angulation on CT was larger in anterior and middle area of the tibial plafond than the posterior area. There was a difference in the degree of varus of the tibial plafond between control group and OA patients; however, there was no difference among patients in different stages of varus ankle OA. Weightbearing plain radiographs underestimate the varus deformity in anterior and middle area of the tibial plafond and there is no significant difference in deformity of the tibial plafond among patients in different stages of varus ankle OA.

Prognostic Factors Affecting Correction Angle Changes After Supramalleolar Osteotomy Using an Opening Wedge Plate for Varus Ankle Osteoarthritis.

Supramalleolar osteotomy (SMO) has been suggested as an effective salvage treatment for varus ankle osteoarthritis. To identify the prognostic factors affecting the correction angle changes after SMO, a total of 53 consecutive patients (58 ankles) were evaluated retrospectively. Clinical and radiologic outcomes were evaluated, and statistical analyses were performed to identify the prognostic factors associated with the clinical and radiologic outcomes. The mean visual analogue scale scores and the American Orthopaedic Foot and Ankle Society scores improved significantly at the final follow-up (both p <.001). The mean tibial-ankle surface (TAS), talar tilt (TT), and tibial-lateral surface angles improved significantly after surgery, compared with the preoperative assessments (all, p <.001). However, at the final follow-up, these angles had changed significantly, compared with their immediate postoperative values (all p <.001), and the changes in the TAS and TT angles significantly influenced the clinical outcomes at the final follow-up (both p <.05). Male sex, high body mass index (≥26.4 kg/m2), and the existence of the lateral cortex breakages were significantly associated with the changes in the TAS and TT angle (all p <.05). Therefore, surgeons should consider these prognostic factors before performing SMO.

Weight-bearing computed tomography findings in varus ankle osteoarthritis: abnormal internal rotation of the talus in the axial plane.

OBJECTIVES: To assess the incidence of abnormal internal rotation of the talus in the axial plane in patients with varus ankle osteoarthritis, and to determine whether this incidence differs from the severity of varus ankle osteoarthritis (moderate versus severe). MATERIALS AND METHODS: We retrospectively evaluated weight-bearing computed tomography (CT) and plain radiographs of 52 ankles with no abnormalities (control group) and 96 ankles with varus osteoarthritis (varus-OA group), which were further stratified into a moderate-OA subgroup (50 ankles) and a severe-OA subgroup (46 ankles). A new radiographic parameter on weight-bearing CT, the talus rotation ratio, was used to assess the rotation of the talus in the axial plane. The normal range of the talus rotation ratio was defined as the 95% prediction interval for talus rotation ratio values in the control group. Abnormal internal rotation of the talus was defined for talus rotation ratio values above the normal range. We determined the incidence of abnormal internal rotation of the talus in the varus-OA group, moderate-OA subgroup, and severe-OA subgroup. RESULTS: In the varus-OA group, the incidence of abnormal internal rotation of the talus was 45% (43 ankles), which corresponded to an incidence of 32% (16 ankles) in the moderate-OA subgroup and 59% (27 ankles) in the severe-OA subgroup (p = 0.013). CONCLUSION: Our study demonstrates that abnormal internal rotation of the talus occurs in patients with varus ankle osteoarthritis, and is more frequently noted in severe than in moderate varus ankle osteoarthritis.

Arthroscopic evaluation of persistent pain following supramalleolar osteotomy for varus ankle osteoarthritis.

PURPOSE: The purposes of this study were to investigate pain experienced by patients after supramalleolar osteotomy for varus ankle osteoarthritis and to analyse correlations between this pain and arthroscopic findings. METHODS: Twenty-nine patients (31 ankles) who underwent arthroscopic evaluation after supramalleolar osteotomy were reviewed retrospectively. The visual analog scale (VAS) was used to assess pain, and the patients were instructed to record the time point, location, and character of the pain. The tibial-ankle surface angle, talar tilt, and tibial-lateral surface angle were measured on radiographs. RESULTS: The location, time point, and character of the pain experienced by the patients changed after supramalleolar osteotomy. The mean VAS score was significantly improved after supramalleolar osteotomy at the time of the arthroscopic evaluation (P < 0.001) and improved further after the arthroscopic procedures (P = 0.026). During arthroscopy, pathologic lesions such as adhesions, synovitis, and soft-tissue impingement were identified. A significant correlation was found between adhesions and dull pain and pain at rest (P = 0.016 and P = 0.005, respectively). In addition, soft-tissue impingement in the lateral gutter was significantly correlated with dull pain, pain at rest, and clicking pain (P = 0.001, P = 0.035, and P = 0.042, respectively). No significant correlations were found between post-operative radiographic measurements and development of pathologic lesions. CONCLUSIONS: With the use of arthroscopy, persistent pain experienced after supramalleolar osteotomy was found to be associated with adhesions, synovitis, and soft-tissue impingement in medial and lateral gutters of the ankle. Arthroscopy can be helpful in identifying and treating painful lesions commonly seen after supramalleolar osteotomy. An understanding of these painful lesions will help patients have more realistic expectations regarding the supramalleolar osteotomy. LEVEL OF EVIDENCE: Case series study, Level IV.

Assessment of Changes in Hindfoot Alignment of Total Ankle Arthroplasty for Ankle Osteoarthritis on Weightbearing Subtalar X-ray View.

Background: Recovering normal hindfoot alignment and correcting deformity of the ankle joint following total ankle arthroplasty (TAA) in osteoarthritis (OA) is essential for improving clinical outcomes and increasing long-term survival. We aim to evaluate hindfoot alignment following standard TAA compared to TAA with a total talar prosthesis ("combined TAA") in varus-type OA patients. Methods: This retrospective study was conducted between 2010 and 2022. We included 27 patients (30 feet) who underwent standard TAA and 19 patients (22 feet) who underwent combined TAA. Hindfoot alignment at the subtalar joint was measured by weightbearing subtalar radiographic view before and after surgery. Results: In the standard TAA, the angle between the tibial shaft axis and the articular surface of the talar dome joint (TTS) changed from 75 to 87 degrees (P < .01), the angle between the tibial axis and the surface on the middle facet (TMC) from 89 to 94 degrees (P < .01), and the angle between the tibial axis and the surface on the posterior facet (TPC) from 80 to 84 degrees (P < .01). The angle between the articular surface of the talar dome and the posterior facet of the calcaneus (SIA) decreased from 4.7 to -2.5 degrees (P < .01). In the combined TAA, TTS angle changed from 77 to 88 degrees (P < .01), TMC angle from 93 to 101 degrees (P < .01), TPC angle from 84 to 90 degrees (P < .05), and SIA from 6.6 to 2.1 degrees (P < .01). Varus deviation to the subtalar joint (TMC, TPC) significantly improved postoperatively in both groups. However, TPC was smaller than TTS and SIA was negative in standard TAA, and TPC was larger than TTS and SIA was positive in combined TAA. Conclusion: The amount of correction of the subtalar joint differed depending on the ligament dissection of the subtalar joint and shape of the talar component. Level of Evidence: Level III, retrospective cohort study.

The Relationship Between the Distal Tibial Fibular Syndesmosis and the Varus Deformity in Patients With Varus Ankle Osteoarthritis.

BACKGROUND: The impact of varus ankle osteoarthritis (OA) on the distal tibial fibular syndesmosis is poorly described. This study aimed to investigate the possible relationship between the condition of the distal tibial fibular syndesmosis and the degree of the varus deformity using weightbearing simulated computed tomography (CT), in patients with varus ankle OA. METHODS: This retrospective comparative study included 155 varus ankles, divided into 4 Takakura-Tanaka groups (stage 2, 3a, 3b, and 4). A control group comprised 35 ankles without prior ankle disorders. The angles between the tibial shaft and the articular surface of the tibial plafond on the anteroposterior view (TAS), and articular surfaces of the tibial plafond and talar dome (TTW) were measured from weightbearing ankle radiographs. The varus angle of the ankle (VA) was defined as 90 - TAS + TTW. On the CT axial view, 1 cm proximal to the tibial plafond, the area of the syndesmosis ("CT-area") and the distance between the fibula and the tibia (CT-FCS) were measured. RESULTS: The CT area in stages 2, 3a, 3b, 4, and control group were 99, 79, 77, 103, and 97 mm2, respectively. The CT-FCS were 3.5, 3.1, 2.9, 4.3, and 3.9 mm, respectively. In all 155 OA ankles, CT area and CT-FCS were negatively correlated with the VA (correlation coefficient r = -0.38, P < .01; and r = 0.38, P < .01, respectively). Both CT area and CT-FCS were significantly smaller in stages 3a and 3b than in the control group (P < .01). CONCLUSION: There may be a relationship between the narrowing of the syndesmosis and the varus deformity in patients with varus ankle OA, especially in stages 3a and 3b. CLINICAL RELEVANCE: Clinicians should be aware of the impact of varus ankle arthritis on the distal tibial fibular syndesmosis when operatively treating varus ankle OA. For some patients, the isolated treatment for the tibiotalar joint may be insufficient, and treatment for the syndesmosis as well as tibiotalar joint may be needed. LEVEL OF EVIDENCE: Level III, retrospective case control study.

Hindfoot Alignment Change After Total Ankle Arthroplasty for Varus Osteoarthritis.

BACKGROUND: In patients with end-stage varus ankle osteoarthritis (OA), hindfoot varus malalignment resulting from the varus deformity of the ankle joint is common. Although total ankle arthroplasty (TAA) performed to correct varus deformity of the ankle joint has the effect of correcting hindfoot alignment, no reports to date have described how much hindfoot alignment correction can be achieved. The purpose of this study was to identify correlation between ankle deformity correction and hindfoot alignment change after performing TAA in patients with end-stage varus ankle OA. METHODS: A total of 61 cases that underwent TAA for end-stage varus ankle OA and followed up for at least 1 year were enrolled for this study. Correlation between changes of tibial-ankle surface angle (TAS), talar tilt (TT), and tibiotalar surface angle (TTS) and changes of hindfoot alignment angle (HA), hindfoot alignment ratio (HR), and hindfoot alignment distance (HD) measured preoperatively and at postoperative year 1 was analyzed. RESULTS: TAS, TT, and TTS changed from 83.9 ± 4.1 degrees, 5.8 ± 5.0 degrees, and 78.1 ± 5.9 degrees, respectively, before operation to 89.2 ± 2.1 degrees, 0.4 ± 0.5 degrees, and 88.7 ± 2.3 degrees, respectively, after operation. HA, HR, and HD also changed from -9.2 ± 4.6 degrees, 0.66 ± 0.18, and -11.2 ± 6.9 mm to -3.7 ± 4.1 degrees, 0.48 ± 0.14, and -5.0 ± 5.3 mm. All the changes were statistically significant (P < .001, respectively). The regression slope of correlation was 0.390 (R2 = 0.654) between TTS and HA; 0.017 (R2 = 0.617) between TTS and HR; and 0.560 (R2 = 0.703) between TTS and HD. CONCLUSION: In patients with end-stage varus ankle OA, changes of hindfoot alignment could be predicted based on degree of ankle deformity corrected with TAA. LEVEL OF EVIDENCE: Level IV, case series.

Supramalleolar osteotomy combined with lateral ligament reconstruction and talofibular immobilization for varus ankle osteoarthritis with excessive talar tilt angle.

BACKGROUND: Although supramalleolar osteotomy is the main joint-preserving method for the treatment of varus ankle osteoarthritis, it tends to be ineffective when ankle osteoarthritis presents in combination with an excessive talar tilt angle. The purpose of this study was to present a new surgical technique, supramalleolar osteotomy combined with lateral ligament reconstruction and talofibular immobilization, for the treatment of varus ankle osteoarthritis with an excessive talus tilt angle and to evaluate the clinical and radiological results. METHODS: From January 2013 to October 2016, a total of 17 patients with 17 cases of varus ankle arthritis with excessive talar tilt angles (larger than 7.3°) underwent surgical treatment using our new technique. The American Orthopaedic Foot and Ankle Society (AOFAS) clinical ankle-hindfoot scale and a visual analogue scale (VAS) were used to evaluate ankle function and pain before surgery and at the last follow-up. The medial distal tibial angle (MDTA), anterior distal tibial angle (ADTA), talar tilt angle (TTA), and hindfoot moment arm values (HMAVs) were evaluated on weight-bearing radiographs acquired preoperatively and at the last follow-up. RESULTS: The AOFAS score improved significantly from 45.8 ± 2.1 before surgery to 84.8 ± 1.8 after surgery (p < 0.001), and the VAS score decreased from 4.9 ± 0.4 to 1.1 ± 0.2 (p < 0.001). The MDTA, TTA, and HMAV changed from 80.9° ± 0.4° to 90.1° ± 0.4°, 11.7° ± 0.6° to 1.4° ± 0.3°, and 12.6 mm ± 0.8 mm to 4.2 mm ± 0.6 mm, respectively (each p < 0.001). The ADTA showed no obvious change (p = 0.370). The staging of 11 cases (65%) improved. Intramuscular vein thrombosis of the lower limbs occurred in 1 patient 1 week after surgery, and superficial infection occurred in 1 patient. CONCLUSIONS: Supramalleolar osteotomy combined with lateral ligament reconstruction and talofibular immobilization can correct the load of the weight-bearing ankle and effectively improve the ankle function. As the talar tilt angle can be significantly improved after surgery, this technique can be used for the treatment of varus ankle osteoarthritis with an excessive TTA.

Novel Double Osteotomy Technique of Distal Tibia for Correction of Asymmetric Varus Osteoarthritic Ankle.

BACKGROUND: A most challenging condition for balancing a varus arthritic ankle is the presence of a defect in the medial tibial plafond. After our initial results with a medial tibial plafondplasty did not fulfill our expectations of success, we hypothesized that adding a correcting supramalleolar osteotomy of the distal tibia would move the loading force to the tibiotalar joint more medially and move the center of rotation of the talus more laterally. In this study, we analyzed midterm clinical and radiographic outcomes in patients with double tibial osteotomy. METHODS: Between January 2005 and February 2010, 20 patients were treated with a medial tibial plafondplasty and a medial supramalleolar osteotomy of the distal tibia. The mean age of the patients was 44 ± 12 years (range, 17-60 years). Follow-up averaged 5.9 ± 2.1 years (range, 4-11.2 years). Weight-bearing radiographs were used to assess osteotomy union and hindfoot alignment. RESULTS: There were no intraoperative or perioperative complications. The average VAS pain score decreased significantly from 7.9 ± 1.3 (range, 6-10) to 1.3 ± 1.6 (range, 0-7). The average AOFAS hindfoot score increased significantly from 49 ± 15 points (range, 36-68) preoperatively to 86 ± 12 points (range, 66-96) postoperatively. The varus tilt improved significantly from 19.4° ± 8.2° (range, 6°-32°) to 6.9° ± 3.9° (range, 1°-12°). CONCLUSION: The novel double osteotomy was found to be an efficient and successful method to restore tibiotalar joint congruency and to normalize hindfoot alignment. LEVEL OF EVIDENCE: Level IV, prospective cohort study.

Extraarticular Supramalleolar Osteotomy for Managing Varus Ankle Osteoarthritis, Alternatives for Osteotomy: How and Why?

The supramalleolar osteotomy has been reported to be a joint preserving surgery with good clinical outcome for asymmetric ankle osteoarthritis, especially varus ankle osteoarthritis. Conventional supramalleolar osteotomy of the tibia and fibula creates angulation and translation of the ankle joint without changing the width of the ankle mortise. Distal tibial oblique osteotomy improved the preoperative clinical and radiological parameters; however, mean talar tilt angle did not decrease. Assessment of the ankle arthritis in sagittal, axial, and coronal planes may be helpful to achieve a decrease of the talar tilt in ankle osteoarthritis.

Additional mesenchymal stem cell injection improves the outcomes of marrow stimulation combined with supramalleolar osteotomy in varus ankle osteoarthritis: short-term clinical results with second-look arthroscopic evaluation.

BACKGROUND: Supramalleolar osteotomy (SMO) is reported to be an effective treatment for varus ankle osteoarthritis by redistributing the load line within the ankle joint. Mesenchymal stem cells (MSCs) have been proposed as a new treatment option for osteoarthritis on the basis of their cartilage regeneration ability. The purpose of this study was to compare the clinical, radiological, and second-look arthroscopic outcomes between MSC injection with marrow stimulation and marrow stimulation alone in patients with varus ankle osteoarthritis who have undergone SMO. METHODS: In this retrospective study, 62 patients (64 ankles) with varus ankle osteoarthritis underwent second-look arthroscopy at a mean of 12.8 months after arthroscopic marrow stimulation combined with SMO; 33 ankles were subjected to marrow stimulation alone (group I), and 31 were subjected to marrow stimulation with MSC injection (group II). Clinical outcome measures included a visual analog scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) score. Radiological outcome variables included the tibial-ankle surface (TAS), talar tilt (TT), and tibial-lateral surface (TLS) angles. In second-look arthroscopy, cartilage regeneration was evaluated using the International Cartilage Repair Society (ICRS) grade. RESULTS: The mean VAS score improved significantly from 7.2 ± 1.0 to 4.7 ± 1.4 in group I and from 7.3 ± 0.8 to 3.7 ± 1.5 in group II at the final follow-up (P < 0.001 for both groups). The mean AOFAS score also improved significantly from 61.7 ± 5.8 to 80.9 ± 6.7 in group I and from 60.6 ± 6.1 to 85.2 ± 5.1 in group II at the final follow-up (P < 0.001 for both groups). There were significant differences in the mean VAS and AOFAS scores between groups at the final follow-up (P = 0.002 and 0.010, respectively). At second-look arthroscopy, there were significant differences in ICRS grades between groups(P = 0.015 for medial aspect of the talar dome, P = 0.044 for medial aspect of the tibial plafond, and P = 0.005 for articular surface of the medial malleolus). ICRS grades were significantly correlated with clinical outcomes in both groups (all P < 0.05). Mean TAS, TT, and TLS angles improved significantly after SMO in both groups but were not significantly correlated with clinical outcomes or ICRS grade (all n.s.). CONCLUSIONS: The clinical and second-look arthroscopic outcomes of MSC injection with marrow stimulation were better compared to those of marrow stimulation alone in patients with varus ankle osteoarthritis who have undergone SMO. Furthermore, the ICRS grade is significantly correlated with clinical outcome.

Supramalleolar Osteotomy With Bone Marrow Stimulation for Varus Ankle Osteoarthritis: Clinical Results and Second-Look Arthroscopic Evaluation.

BACKGROUND: Supramalleolar osteotomy (SMO), which redistributes the load line within the ankle joint, has been reported as an effective treatment for varus ankle osteoarthritis. However, no study has examined cartilage regeneration in the medial compartment of the ankle after SMO. HYPOTHESIS/PURPOSE: This study aimed to investigate the clinical and radiological outcomes of SMO and to identify the association between the outcomes of SMO and cartilage regeneration evaluated by second-look arthroscopy. The hypothesis was that cartilage regeneration would be an important predictor of the outcomes of SMO and that arthroscopic marrow stimulation would aid in cartilage regeneration. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 31 ankles were retrospectively evaluated after arthroscopic marrow stimulation with SMO for varus ankle osteoarthritis; second-look arthroscopy was conducted for all these ankles. Clinical outcome measures included a visual analog scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) score. Radiological outcome variables included the tibial-ankle surface angle (TAS), talar tilt (TT), and tibial-lateral surface angle (TLS), and progression of degenerative arthritis of the ankle was assessed. In the second-look arthroscopy, cartilage regeneration was evaluated using the International Cartilage Repair Society (ICRS) grade. RESULTS: The mean ± standard deviation VAS and AOFAS scores were 7.1 ± 0.8 and 62.9 ± 4.0 preoperatively, and they significantly improved to 3.4 ± 1.3 and 83.1 ± 7.5, respectively (P < .001, for both) at the time of the second-look arthroscopy (mean, 13.2 months postoperatively). However, at final follow-up (mean, 27.4 months postoperatively), they were significantly decreased to 4.1 ± 1.6 and 79.9 ± 8.0, respectively, compared with the values at second-look arthroscopy (P < .001, for both). The mean TAS, TT, and TLS improved significantly after SMO but showed no significant correlation with the clinical outcomes and ICRS grade (P > .05 for all three). At second-look arthroscopy, the ICRS overall repair grades were normal in 1 (3%), nearly normal in 7 (23%), abnormal in 13 (42%), and severely abnormal in 10 (32%). Progressive degenerative arthritis was observed in 13 cases (42%). The ICRS grade was significantly associated with the clinical outcomes (P < .0001) and development of degenerative arthritis of the ankle joint (P = .002). CONCLUSION: This study showed improved clinical outcomes after SMO for varus ankle osteoarthritis in comparison to the preoperative assessments. Furthermore, the ICRS grade was significantly associated with the clinical outcomes of SMO at final follow-up and significantly associated with the development of degenerative arthritis of the ankle joint. Therefore, arthroscopic marrow stimulation should be considered with SMO to ensure adequate cartilage regeneration. However, given the ICRS grades observed at the time of the second-look arthroscopies and the progression of degenerative arthritis in 42%, the long-term prognosis in this group of patients is uncertain.