Spontaneous Osteonecrosis Of The Knee Research Articles

Spontaneous Osteonecrosis of the Knee (Ahlbäck's disease) in Children, and Overview

Spontaneous Osteonecrosis of the Knee (Ahlbäck's disease) in Children, and Overview

Targeting Adenosine Signalling in Knee Chondropathy: The Combined Action of Polydeoxyribonucleotide and Pulsed Electromagnetic Fields: A Current Concept Review.

Chondropathy of the knee is one of the most frequent degenerative cartilage pathologies with advancing age. Scientific research has, in recent years, advanced new therapies that target adenosine A2 receptors, which play a significant role in human health against many disease states by activating different protective effects against cell sufferance and damage. Among these, it has been observed that intra-articular injections of polydeoxyribonucleotides (PDRN) and Pulsed Electromagnetic Fields (PEMF) can stimulate the adenosine signal, with significant regenerative and healing effects. This review aims to depict the role and therapeutic modulation of A2A receptors in knee chondropathy. Sixty articles aimed at providing data for our study were included in this review. The present paper highlights how intra-articular injections of PDRN create beneficial effects by reducing pain and improving functional clinical scores, thanks to their anti-inflammatory action and the important healing and regenerating power of the stimulation of cell growth, production of collagen, and the extracellular matrix. PEMF therapy is a valid option in the conservative treatment of different articular pathologies, including early OA, patellofemoral pain syndrome, spontaneous osteonecrosis of the knee (SONK), and in athletes. PEMF could also be used as a supporting therapy after an arthroscopic knee procedure total knee arthroplasty to reduce the post-operative inflammatory state. The proposal of new therapeutic approaches capable of targeting the adenosine signal, such as the intra-articular injection of PDRN and the use of PEMF, has shown excellent beneficial results compared to conventional treatments. These are presented as an extra weapon in the fight against knee chondropathy.

Unicompartmental knee arthroplasty (UKA) for primary spontaneous osteonecrosis of the knee (SONK): a systematic review.

The role of unicompartmental knee arthroplasty (UKA) in spontaneous osteonecrosis of the knee (SONK) is still controversial. We performed a systematic review to evaluate all available current literature on UKA in the setting of SONK. A comprehensive electronic research was performed using the PubMed, Embase, Web of Science, and Cochrane databases with keywords related to SONK and knee arthroplasty. Studies were selected with predetermined inclusion criteria: 1) studies that specifically assessed SONK treated with UKA; 2) studies reporting implant survival rate and global clinical outcomes; 3) studies with a minimum follow up of 1 year. We excluded articles not written in English, articles that did not differentiate between primary and secondary osteonecrosis and articles published before 2000. The overall research process produced 19 studies. We extrapolated data of a total of 717 unicompartimental knee arthroplasty procedures (1,39% lateral UKA, 98,61% medial UKA). Extracted data include years of follow-up, patient demographics, laterality of lesion, radiological findings, unicompartimental knee arthroplasty implants, reason of revision, revision rate, maximum knee flexion, knee clinical outcomes score, and Kaplan-Meier survival curves. The data collected show that UKA had acceptable survival rates as well as revision rates and good clinical outcomes both in the short- and long-term. UKA is an optimal treatment choice for primary SONK when correctly indicated in a carefully selected subset of patients, with no significant difference compared to osteoarthritis. Attention must be paid to distinguish the primary from secondary SONK, as the latter could lead to worse outcomes.

The safety and cost-analysis of simultaneous versus staged bilateral total knee arthroplasty in a Taiwan population.

In patients with advanced osteoarthritis (OA) of the bilateral knees, uncertainty remains as to whether simultaneous bilateral total knee arthroplasty (SiTKA) or staged TKA (StTKA) is the treatment of choice. The purpose of this study was to investigate the safety and relative cost of SiTKA vs StTKA in Taiwan patients. Using the Big Data Center of Taipei Veterans General Hospital, we retrospectively reviewed all patients who underwent SiTKA or StTKA due to OA or spontaneous osteonecrosis of the knee from January 2011 to December 2016. We assessed length of stay, transfusion rate, early postoperative complications, 30- and 90-day readmission rate, 1-year reoperation rate, and the indication for reoperation. Furthermore, we analyzed the total cost of the two groups, including reimbursement from the national health insurance (NHI), cost of the procedures, and net income from each case. A total of 2016 patients (1565 SiTKA and 451 StTKA) were included in this study. The two groups had no significant differences in rates of complications, 30- and 90-day readmission, or 1-year reoperation. The length of stay was on average 5.0 days longer for StTKA ( p < 0.01). In terms of cost, all categories of medical costs were significantly lower for SiTKA, while the net hospital income was significantly higher for StTKA. SiTKA is a safe and cost-effective surgery. Both SiTKA and StTKA have similar rates of postoperative complications, readmission and reoperation, but SiTKA significantly reduces medical expenses for both the patient and the NHI.

Magnetic resonance imaging of subchondral insufficiency fractures in the knee (literature review)

Stress fractures are an actual problem of modern medicine. A fracture associated with insufficiency of the bone tissue of the knee condyles is a new type of stress fracture that occurs in people aged 50–55 years in response to a normal daily activity, but with damage to the weakened subchondral bone tissue of the joint caused by various reasons. This literature review is mainly based on data from foreign medical sources, since there is very little information on this type of fracture in Russian sources. This is primarily due to the fact that initially the world and Russian medical communities designated this type of fracture as a spontaneous osteonecrosis of the knee (SONK). In recent years, this term has been revised abroad and replaced by a more suitable one – subchondral insufficiency fracture of the knee (SIF/SIFK). According to modern concepts, it is necessary to clearly distinguish among the concepts of osteonecrosis and subchondral insufficiency fracture of the knee. The reason for this is not only differences in the pathogenesis of these pathologies, but also fundamentally different approaches to managing these patients. Thus, taking into account the fundamental differences in the treatment of patients with stress fracture associated with bone insufficiency and patients with osteonecrosis, and also the relevance of stress fracture of the knee condyles, we state the following aim – to study the available literature on this problem.

Spontaneous Osteonecrosis of the Knee: State of the Art.

Osteonecrosis is a terrible condition that can cause advanced arthritis in a number of joints, including the knee. The three types of osteonecrosis that can affect the knee are secondary, post-arthroscopic, and spontaneous osteonecrosis of the knee (SPONK). Regardless of osteonecrosis classification, treatment for this condition seeks to prevent further development or postpone the onset of knee end-stage arthritis. Joint arthroplasty is the best course of action whenever there is significant joint surface collapse or there are signs of degenerative arthritis. The non-operative options for treatment at the moment include observation, nonsteroidal anti-inflammatory medications (NSAIDs), protective weight bearing, and analgesia if needed. Depending on the severity and type of the condition, operational procedures may include unilateral knee arthroplasty (UKA), total knee arthroplasty (TKA), or joint preservation surgery. Joint preservation techniques, such as arthroscopy, core decompression, osteochondral autograft, and bone grafting, are frequently used in precollapse and some postcollapse lesions, when the articular cartilage is typically unaffected and only the underlying subchondral bone is affected. In contrast, operations that try to save the joint following significant subchondral collapse are rarely successful and joint replacement is required to ease discomfort. This article's goal is to summarise the most recent research on evaluations, clinical examinations, imaging and various therapeutic strategies for osteonecrosis of the knee, including lesion surveillance, medicines, joint preservation methods, and total joint arthroplasty.

Intramedullary rod insertion places the femoral component more laterally during Oxford medial unicompartmental knee arthroplasty

BackgroundThis study aims to assess the influence of intramedullary rods on the implantation positions of femoral components using Microplasty instrumentation in Oxford unicompartmental knee arthroplasty. We hypothesized that femoral components can be laterally implanted incorrectly when using intramedullary rods.MethodsThis prospective study included all 45 consecutive patients (53 knees) who underwent Oxford unicompartmental knee arthroplasty surgery for anteromedial osteoarthritis or spontaneous osteonecrosis of the knee at our hospital during the study period. A custom-made toolset comprising a triangular caliper and circular trial bearings was used to evaluate the distance between the bearing and the vertical wall of the tibia implant (wall-bearing space) using the caliper at 90° flexion both with and without intramedullary rods.ResultsThe wall-bearing space was significantly larger when the intramedullary rod was used than when intramedullary rod was not used (1.8 ± 1.1 mm versus 3.4 ± 1.2 mm, P < 0.001). The mean difference of wall-bearing space with and without intramedullary rod was 1.6 ± 0.7 mm.ConclusionsFemoral components can be laterally implanted incorrectly by an average of 1.6 mm when using intramedullary rods. The wall-bearing space should be evaluated using trial components, and if the relationship is improper, it should be corrected before keel slot preparation.

Transient spontaneous osteonecrosis of the knee (SONK) shortly after SARS-CoV-2 infection: A report of 2 cases

This article describes 2 cases of post-coronavirus disease 2019 (COVID-19) transient spontaneous osteonecrosis of the knee (PCT-SONK) observed in patients who had previously recovered from COVID-19 without corticosteroid administration. The possible pathomechanisms by which a recent SARS-CoV-2 infection may contribute as a causative factor for osteonecrosis are reviewed, and the differential diagnosis and treatment are discussed. Two patients (males, 45- and 47-year-old) presented with sudden onset knee pain with no trauma history. The pain persisted during rest and at night. On magnetic resonance imaging (MRI), no subchondral bone thickening was observed; bone edema was diffusely distributed in the whole femoral condyle, in contrast to the more focal edema that is typically concentrated mainly around the subchondral region in classic SONK. Both patients were treated nonoperatively with no weight bearing and pharmacological agents, and complete resolution of symptoms was achieved. A follow-up MRI 10 weeks after presentation revealed a near-complete loss of signal in the medial femoral condyle in both patients. Orthopedic surgeons should be cautious when sudden knee pain without concurrent trauma or a history of injury occurs shortly after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, even with mild COVID-19 illness. While some studies report the development of post-COVID-19 osteonecrosis after lower doses of corticosteroids and sooner after their administration than in comparable non-COVID-19 cases, our study is the first to report 2 cases with no corticosteroid administration at all. Therefore, the authors believe it adds to the body of knowledge on the potential connections between COVID-19 and PCT-SONK. The transient nature of symptoms and radiological findings suggest that aggressive surgical treatment of non-injury local bone edema occurring shortly after SARS-CoV-2 infection should be avoided.

Proximal fibular osteotomy relieves pain in spontaneous osteonecrosis of the knee: A retrospective study.

Spontaneous osteonecrosis of the knee (SONK) causes knee pain and joint motion limitation. Ischemia or insufficiency fracture may be the cause, but no consensus has been developed. Proximal fibular osteotomy (PFO) has been reported to relieve pain from osteoarthritis through medial compartment decompression. We reviewed the effect of this procedure on medial compartment SONK patients and explored clinical and radiological results.Since January 2018 to January 2020, the data of 12 knees (8 right and 4 left) from 11 SONK patients (9 women and 2 men) who received PFO were analyzed. The average age was 61.5 years. The diagnosis of SONK was established through weight-bearing anterior–posterior radiographs or magnetic resonance imaging (MRI). Visual analog scale (VAS) scores, Oxford knee score (OKS), Femorotibial angle (FTA), medial joint space, and lateral joint space were documented preoperatively and at follow up visits. Outcome assessment for the clinical and radiographic data was reviewed at 12- and 24-month follow-up visits.The mean follow up period was 33 months. All patients were able to walk with or without cane assistance the day after surgery. Both VAS score and OKS (preoperative: 6.6 ± 0.9 and 24.7 ± 3.8, respectively) improved significantly at the 12-month follow-up, and to 24-month follow-up (3.6 ± 1.3 and 35.6 ± 4.5, respectively, P < .05). Medial joint space ratio increased from 0.36 to 0.50 (P < .05). Changes of FTA were insignificant at any point of follow up. Four patients underwent follow-up MRI, and a decrease in the osteonecrotic area was clearly observed in 2 patients.By achieving medial knee decompression, PFO allowed quick weight-bearing recovery, pain relief, and improvement in knee function in SONK patients.

Current Radiological Aspects of Subchondral Insufficiency Fracture of the Knee

Subchondral stress insufficiency fracture of the knee is a new type of fracture that occurs in people of the older age group (from 50–55 years old) when exposed to a normal load on weakened bone trabeculae. In Russian sources, there is few information about this type of fracture. This is primarily due to the fact that initially the world and domestic medical communities designated this type of pathology as “spontaneous osteonecrosis of the knee”. In recent years, this term has been revised abroad and replaced by a more suitable one – “subchondral insufficiency fracture”. The etiology of insufficiency fracture is based on many diseases and conditions that lead to bone tissue weakening (osteoporosis, collagenosis, rheumatoid arthritis, post-radiation changes in bones, etc.). The main method for diagnosing this type of fracture is magnetic resonance imaging, since it is able to detect a fracture at any stage (especially at an early one). According to modern concepts, the terms “osteonecrosis” and “subchondral insufficiency fracture” require completely different approaches to the treatment. In the presence of complications, a fracture of insufficiency of the knee joint condyles threatens with subchondral collapse and secondary osteoarthritis, which leads to disability of a patient. Given the relevance of this medical problem, the aim of the review is to show the current state of literature data on the issue.

Biological Effects of High Tibial Osteotomy on Spontaneous Osteonecrosis of the Knee.

ObjectiveThe purpose of this study was to evaluate the postoperative status of spontaneous osteonecrosis of the knee (SONK) after high tibial osteotomy (HTO) with concomitant bone marrow stimulation (BMS) using synovial fluid (SF) biomarkers.DesignTwenty patients with SONK who underwent opening wedge HTO were enrolled. Paired SF samples from the affected knee were collected at the time of HTO surgery and at the time of plate removal. SF concentrations of interleukin (IL)-6, IL-8, and matrix metalloproteinase (MMP)-13 were measured by enzyme-linked immunosorbent assays. The Knee Society Score (KSS) and hip-knee-ankle (HKA) angle were assessed before and 2 years after HTO.ResultsThe KSS knee and function scores were significantly improved after HTO (mean changes of 33.8 and 29.4, respectively). The mean HKA angle was changed from mechanical varus (−8.6°) to valgus (5.2°). Concentrations of IL-6, IL-8, and MMP-13 were significantly decreased after HTO (mean changes of −73.7%, −32.4%, and −47.9% from preoperative baseline, respectively). Significant correlations were found between lesion size and concentrations of biomarkers, except for preoperative MMP-13.ConclusionsSF levels of biomarkers of inflammation and cartilage degradation were reduced after HTO with a concomitant BMS procedure, suggesting a biological improvement in SONK.

Minimum 5-Year Outcomes of Osteochondral Autograft Transplantation with a Concomitant High Tibial Osteotomy for Spontaneous Osteonecrosis of the Knee with a Large Lesion.

The purpose of this study was to evaluate the mid-term clinical outcomes of osteochondral autograft transplantation (OAT) with concomitant high tibial osteotomy (HTO) in spontaneous osteonecrosis of the knee (SONK) with a large lesion. A total of 48 knees of 48 consecutive patients with SONK (lesion size ≥4 cm2, no age criteria) who underwent opening wedge HTO and concomitant OAT were retrospectively investigated, and those who were followed up postoperatively for at least 5 years were included in this case series study. Clinical outcomes were evaluated using knee and function scores of Knee Society Score, radiographic outcomes were evaluated using the anatomical femorotibial angle (FTA), and these outcomes were compared between patients aged ≥70 years and <70 years. Of the 48 cases, a total of 43 cases were available for review at a minimum of 5 years, and 5 cases were excluded from the analysis. Overall, the mean knee score improved from preoperative 48.8 ± 13.3 to postoperative 87.9 ± 8.6 at 1 year (P < 0.05) and 85.0 ± 10.4 at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). The mean function score also improved from preoperative 60.1 ± 10.9 to postoperative 87.3 ± 12.2 at 1 year (P < 0.05) and 84.2 ± 12.4 at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). The mean standing FTA was corrected significantly from 181.1° ± 2.7° preoperatively to 169.7° ± 2.4° at 1 year (P < 0.05) and 169.4° ± 3.1° at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). There were no significant differences in clinical and radiographic outcomes between patients aged ≥70 years and <70 years. There were 4 cases of lateral hinge fracture around the osteotomy site and 1 case of delayed union. None of the patients underwent revision surgery during the follow-up period (survival rate of 100%). Mid-term clinical outcomes of patients with SONK who underwent HTO and OAT with a relatively large lesion were good.

MRI diagnostics of a new type of stress subchondral insufficiency fracture of the knee

Subchondral insufficiency fracture of the knee is a new type of stress fracture, which was previously referred to as spontaneous osteonecrosis of the knee (SONK).Aim. To determine the informativeness of radiography and magnetic resonance imaging in subchondral fracture of knee insufficiency.Material and Methods. The study comprised 150 patients including 48% of men and 52% of women. The age of patients ranged from 46 to 82 years. The patients underwent radiography and magnetic resonance imaging of the knee joint followed by the calculation of sensitivity, specificity and accuracy of the methods.Results. The most common stress fracture of insufficiency was found in the medial condyle of the femur (79%) with the second most common in the lateral condyle of the femur (12%). Most fracture zones (7.9%) were localized in the medial condyle of the tibia, and only 1.1% of fracture zones were in the lateral condyle of the tibia. The informativeness of radiography was low: sensitivity of 68.4%, specificity of 30.0%, and accuracy of 55.1%. Parameters of magnetic resonance imaging informativeness were as follows: sensitivity of 100%, specificity of 99.0%, and accuracy of 98.0%.Conclusion. Magnetic resonance imaging is the method of choice for stress fracture knee insufficiency because it demonstrated very high indicators of informativeness.

Osteonecrosis of the knee: a concise review of the current literature

Osteonecrosis (ON) of the knee is a progressive disease that can lead to subchondral collapse and end-stage osteoarthritis of the knee. Originally described as a single disease, it includes three different pathologic entities: spontaneous osteonecrosis of the knee (SONK), secondary osteonecrosis of the knee, and post-arthroscopic osteonecrosis of the knee. This article reviews the current literature of these three different conditions by describing their epidemiology, etiology and pathogenesis, clinical presentations and radiographic findings. Various treatment option (e.g., core decompression, bone grafting, stem cells implantation, tibial osteotomy and arthroplasty), available for each entities are reviewed.

Efficiency of High-Resolution MRI at Different Stages of Subchondral Insufficiency Fracture of the Knee

The history of subchondral insufficiency fracture is closely related to a pre-existing diagnosis of spontaneous osteonecrosis of the knee (SONK). Previously, it was thought that subchondral linear or lunate pathological changes on magnetic resonance imaging (MRI) scans in elderly patients with a history of osteoporosis are the result of spontaneous osteonecrosis, but in the 2000s, studies by T. Yamamoto showed that a small proportion of patients with osteonecrosis of the femoral head initially have a fracture of insufficiency that gets complicated by secondary osteonecrosis. Subsequent studies of SONK also showed that the subchondral insufficiency fracture is precisely the initial process, osteonecrosis is secondary and it is a complication of the fracture. The aim of our study was to evaluate the effectiveness of high-resolution MRI at different stages of this disease.

Effects of Korean Traditional Medicine Treatment on Spontaneous Osteonecrosis of the Knee: A Case Report

Spontaneous osteonecrosis of the knee (SONK) is a common form of osteonecrosis of the knee and mainly affects the medial condyle due to localized vascular insufficiency. We report a case of SONK in a 65-year-old woman who had severe knee pain in her left knee whichimpeded her capacityto walk beyond 10 minutes. Bilateral knee X-rays revealed degenerative osteoarthritis of both knees and magnetic resonance imaging revealed R/O SONK in the lateral aspect of the medial femoral condyle, as well as a medial meniscal posterior horn root tear, and a Grade 1 medial collateral ligament injury. She was hospitalized at Jaseng Hospital of Korean Medicine for 21 days and receivedcombination therapy includingacupuncture, pharmacopuncture, and herbal medicine. Patient-reported scales indicated that her pain and physical functional limitations were alleviated. Combination therapy consisting of Korean traditional medicine may bean alternative non-operative treatment approach for patients with SONK.

The Renaissance of Unicompartmental Knee Arthroplasty appears rational - A radiograph-based comparative Study on adverse Events and patient-reported Outcomes in 353 TKAs and 98 UKAs.

PurposeTotal knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) are both considered suitable for antero-medial osteoarthritis and spontaneous osteonecrosis of the knee. National registry data are consistent in showing higher revision rates for UKA. Adequately adjusted, these findings may be challenged by differences in adverse events and patient-reported outcomes, as both can have serious long-term implications. Based on preoperative radiographs, the aim was to retrospectively compare the two principle surgeries in these respects.MethodsAll TKA procedures in 2016 in one Swedish county council were, according to certain radiograph-based consensus criteria, visually evaluated for medial UKA suitability. Then, using different regression models, they were compared with the corresponding medial UKAs performed in 2015–2017 regarding complications and patient-reported outcomes one year after surgery.ResultsThe UKA group showed an 82% reduced risk (OR 0.2; 95% CI 0.0–0.6) of any complications, whereas the 55% reduced risk of severe complication did not reach statistical significance (OR 0.5; 95% CI 0.1–2.1). These findings corresponded in high-volume surgeries to an absolute complication rate of 0% in the UKA group and 10% in the TKA group (p = 0.005) and to a severe complication rate of 0% and 5% respectively (p = 0.05). Though no differences were seen in any general patient-reported outcomes, the pain and function based OMERACT-OARSI responder criteria indicated in both around a 60% better chance of any response (OR 1.6 CI % 0.6–4.5) and a high response (OR 1.6; 95% CI 0.7–3.4) in the UKA group.ConclusionNo differences were shown in patient-reported outcomes but a clear difference in risk of complications, favoring the UKA procedure.

Medial meniscus extrusion as a predictor for a poor prognosis in patients with spontaneous osteonecrosis of the knee

BackgroundRisk factors for the progression of spontaneous osteonecrosis of the knee (SONK) remain unclear. The purpose of this study was to investigate the association between magnetic resonance imaging (MRI) findings of the meniscus and the prognosis of SONK. MethodsA total of 78 consecutive patients (female 85%; mean age 75.6 ± 7.2 years old) diagnosed with SONK were included. Of these, 30 patients did not receive surgery within 1 year from the onset of SONK (conservative group), while the remaining 48 patients underwent unicompartmental knee arthroplasty due to worsening of symptoms (UKA group). Using MRI findings obtained within 3 months of the onset, we compared the types of meniscus tear and medial meniscus extrusion between the conservative group and UKA group. We performed a receiver operating characteristics (ROC) analysis to estimate the cut-off value. ResultsPatients in the UKA group showed greater medial meniscus extrusion (absolute value, 4.2 mm ± 1.9 vs. 2.8 mm ± 1.2, P = 0.001; relative percentage of extrusion (RPE), 45.7% ± 21.5 vs. 30.7% ± 12.9, P = 0.001) and a higher prevalence of radial tear (P = 0.021) than those in the conservative group. In the multivariate analysis, RPE remained a relevant independent factor (P = 0.035) for future UKA. An ROC analysis found that the cut-off point of RPE was 33% (sensitivity, 81.2%; specificity, 63.3%). ConclusionRPE was a predictor of the prognosis of patients who underwent UKA within 1 year after the onset of SONK. Our results suggest that patients with RPE ≥ 33% are at high risk for progression.

Postmeniscectomy osteonecrosis of the knee: A case report and literature review

Postarthroscopic osteonecrosis of the knee (PAONK) is a rare form of osteonecrosis for which the pathogenesis and etiology remain poorly understood; however, there is evidence of a close association with meniscectomy in most PAONK cases. Based on this evidence, postmeniscectomy osteonecrosis of the knee (PMONK) has been suggested as a new category. As early diagnosis and appropriate treatment can improve prognosis, there is a need to differentiate PMONK from spontaneous osteonecrosis of the knee (SONK). This differentiation is specifically important in the Middle East and Arab countries where PMONK and PAONK have not been reported before, which could have resulted from under-reporting or under-diagnosis. To address this gap, we present a case of PMONK from this region and discuss assessment findings and treatment relative to the current evidence.

A Retrospective Study of Unicompartmental Knee Arthroplasty Functional Outcome and the Incidence of Medial Meniscus Posterior Root Tear in Spontaneous Osteonecrosis of the Knee.

Background Spontaneous osteonecrosis of the knee (SONK) can lead to severe knee osteoarthritis predominantly localized to the medial compartment. We aimed to determine whether unicompartmental knee arthroplasty was an effective treatment for primary SONK. Methods We analyzed the functional outcomes in 23 patients with SONK (with a magnetic resonance imaging- (MRI-) confirmed diagnosis) who underwent UKA at a single center. The mean follow-up time was 67 months post-UKA. Results Significant improvements in function were indicated by reduced Oxford Knee and Visual Analogue Scale scores after UKA, and there were no specific complications after the procedures. The incidence of MRI-identified medial meniscus posterior root tear (MMPRT) was 69.6% (16/23). Conclusion Unicompartmental arthroplasty for SONK is less destructive to the native knee structure than total knee arthroplasty but can achieve comparable prognosis with strict patient selection. While the precise etiology of SONK is unknown, one theory posits that a MMPRT may change the biomechanical circumstances of the knee joint, leading to osteonecrosis. Although not confirmatory, the high prevalence rate suggests that MMPRT may have a key role in the development of SONK. UKA is an effective treatment option for SONK, resulting in significant functional improvement. Long-term (>10 years) outcomes should be investigated.