Fresh Osteochondral Allograft Transplantation for Spontaneous Osteonecrosis of the Knee: A Case Series

Subchondral insufficiency fracture of the medial femoral condyle treated conservatively with early non-weightbearing

Spontaneous osteonecrosis of the knee (SONK) is a poorly understood but debilitating disease, that is a common cause of unilateral acute knee pain and swelling. The term "SONK" has been replaced by the term "subchondral insufficiency fracture" in the latest pathology and imaging literature. Few studies investigated the pathogenesis of SONK by examining the histological changes of the tissues. Very recently, the development of SONK was associated with a meniscal root tear. In terms of the preferred imaging, plain radiographs can confirm the diagnosis in late stages; however, magnetic resonance imaging (MRI) scan is often required. Regarding the treatment, conservative management is usually the treatment of choice in early stages, including a period of non-weightbearing or the use of medications, such as nonsteroidal anti-inflammatory drug (NSAIDS) or bisphosphonates. However, when SONK progresses, often a surgical intervention is required, such as knee replacement, but also minimally invasive techniques, such as arthroscopic intervention, have been described. We present a case of early SONK and discuss the possible pathogenesis of SONK, the clinical presentation, the radiological findings, and we focus on the importance of early diagnosis and early off-load period that is required to prevent further progression of the disease.

Characteristics and Clinical Outcomes After Osteochondral Allograft Transplantation for Treating Articular Cartilage Defects: Systematic Review and Single-Arm Meta-analysis of Studies From 2001 to 2020

Background

Osteochondral allograft transplantation (OCA) treats symptomatic focal cartilage defects with satisfactory clinical results.

Purpose

To comprehensively analyze the characteristics and clinical outcomes of OCA for treating articular cartilage defects.

Study Design

Systematic review; Level of evidence, 4.

Methods

We searched Embase, PubMed, Cochrane Database, and Web of Science for studies published between January 1, 2001, and December 31, 2020, on OCA for treating articular cartilage defects. Publication information, patient data, osteochondral allograft storage details, and clinical outcomes were extracted to conduct a comprehensive summative analysis.

Results

In total, 105 studies involving 5952 patients were included. The annual reported number of patients treated with OCA increased from 69 in 2001 to 1065 in 2020, peaking at 1504 cases in 2018. Most studies (90.1%) were performed in the United States. The mean age at surgery was 34.2 years, and 60.8% of patients were male and had a mean body mass index of 26.7 kg/m2. The mean lesion area was 5.05 cm2, the mean follow-up duration was 54.39 months, the mean graft size was 6.85 cm2, and the number of grafts per patient was 54.7. The failure rate after OCA was 18.8%, and 83.1% of patients reported satisfactory results. Allograft survival rates at 2, 5, 10, 15, 20, and 25 years were 94%, 87.9%, 80%, 73%, 55%, and 59.4%, respectively. OCA was mainly performed on the knee (88.9%). The most common diagnosis in the knee was osteochondritis dissecans (37.9%), and the most common defect location was the medial femoral condyle (52%). The most common concomitant procedures were high tibial osteotomy (28.4%) and meniscal allograft transplantation (24.7%). After OCA failure, 54.7% of patients underwent revision with primary total knee arthroplasty.

Conclusion

The annual reported number of patients who underwent OCA showed a significant upward trend, especially from 2016 to 2020. Patients receiving OCA were predominantly young male adults with a high body mass index. OCA was more established for knee cartilage than an injury at other sites, and its best indication was osteochondritis dissecans. This analysis demonstrated satisfactory long-term postoperative outcomes.

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 With Mosaicplasty Alone

PURPOSE

To determine the magnetic resonance imaging (MRI) findings after mosaicplasty (MOS) for knee subchondral insufficiency fracture (SIFK), and to analyze the relationship between MRI findings and clinical outcomes.

METHODS

We retrospectively reviewed the cases of consecutive patients who underwent MOS for SIFK with/without high tibial osteotomy (HTO) between January 1998 and December 2015. The MRI findings at 12 months after the surgery were assessed by the modified magnetic resonance observation of cartilage repair tissue (MOCART) score to determine the degree of bone marrow edema (BME), plug union, and plug necrosis. The clinical outcomes were assessed by Lysholm score to clarify the minimal clinically important difference (MCID) and patient acceptable symptom state analysis.

RESULTS

In total, 58 patients (17 men and 41 women) were enrolled in this study. Among them, 30 knees were treated by MOS alone and 28 knees were treated by MOS with HTO. The MOCART scores of patients who received MOS alone were significantly lower in BME score (P = .0060), plug union score (P = .0216), and in plug necrosis score (P = .0326) than patients who received MOS with HTO. BME lesion was less likely to persist among elderly (odds ratio 1.20, P = .0248) and female (OR 41.8, P = .0118) patients. The MCID of Lysholm score was 6.6 in MOS alone and 8.4 in MOS with HTO cases, but there were no significant association between MRI findings and the postoperative Lysholm score.

CONCLUSIONS

The MOS with HTO cases had better MOCART scores with less BME, better plug union, and less plug necrosis compared with MOS alone cases. Female and older patients had better resolution of BME, but there was no significant correlation between MRI findings and the postoperative Lysholm score. All cases in both groups showed improvement of Lysholm score exceeding MCID; thus, MOS may be effective as a joint preserving surgery for SIFK.

LEVEL OF EVIDENCE

Level IV, clinical case series.

Osteonecrosis of the Knee: Not all Bone Edema is the Same

Knee pain is among the most common complaints that an orthopedic surgeon may see in practice. It is often worked up with X-rays and MRI, leading to a myriad of potential diagnoses ranging from minimal edema patterns to various types of osteonecrosis. Similarities in certain causes can pose diagnostic challenges. The purpose of this review was to present the 3 types of osteonecrosis observed in the knee as well as additional causes to consider to help aid in the diagnosis and treatment..

A Case of Subchondral Insufficiency Fracture of the Knee at Lateral Femoral Condyle Treated With Unicompartmental Knee Arthroplasty

Spontaneous insufficiency fracture of the knee is a potentially devastating yet poorly understood disease entity that can lead to secondary osteoarthritis. Most cases involve the medial femoral condyle, and the lateral femoral condyle is rarely affected. The optimal treatment for spontaneous insufficiency fracture of the lateral femoral condyle remains undetermined, and there are no previous dedicated reports on treatment outcome with unicompartmental knee arthroplasty. A middle-aged lady presented with subacute left knee pain and a locked knee. Subsequent imaging studies revealed a spontaneous insufficiency fracture of the lateral femoral condyle. In view of the isolated compartment involvement, unicompartmental knee arthroplasty was performed with satisfactory outcome. At 1 year postoperatively, the patient had complete resolution of knee pain and was able to resume working.

Metrics of OsteoChondral Allografts (MOCA) Group Consensus Statements on the Use of Viable Osteochondral Allograft

Background:

Osteochondral allograft (OCA) transplantation has evolved into a first-line treatment for large chondral and osteochondral defects, aided by advancements in storage protocols and a growing body of clinical evidence supporting successful clinical outcomes and long-term survivorship. Despite the body of literature supporting OCAs, there still remains controversy and debate in the surgical application of OCA, especially where high-level evidence is lacking.

Purpose:

To develop consensus among an expert group with extensive clinical and scientific experience in OCA, addressing controversies in the treatment of chondral and osteochondral defects with OCA transplantation.

Study Design:

Consensus statement.

Methods:

A focus group of clinical experts on OCA cartilage restoration participated in a 3-round modified Delphi process to generate a list of statements and establish consensus. Questions and statements were initially developed on specific topics that lack scientific evidence and lead to debate and controversy in the clinical community. In-person discussion occurred where statements were not agreed on after 2 rounds of voting. After final voting, the percentage of agreement and level of consensus were characterized. A systematic literature review was performed, and the level of evidence and grade were established for each statement.

Results:

Seventeen statements spanning surgical technique, graft matching, indications, and rehabilitation reached consensus after the final round of voting. Of the 17 statements that reached consensus, 11 received unanimous (100%) agreement, and 6 received strong (80%-99%) agreement.

Conclusion:

The outcomes of this study led to the establishment of consensus statements that provide guidance on surgical and perioperative management of OCAs. The findings also provided insights on topics requiring more research or high-quality studies to further establish consensus and provide stronger evidence.

Autologous costal chondral transplantation and costa-derived chondrocyte implantation: emerging surgical techniques

It is a great challenge to cure symptomatic lesions and considerable defects of hyaline cartilage due to its complex structure and poor self-repair capacity. If left untreated, unmatured degeneration will cause significant complications. Surgical intervention to repair cartilage may prevent progressive joint degeneration. A series of surgical techniques, including biological augmentation, microfracture and bone marrow stimulation, autologous chondrocyte implantation (ACI), and allogenic and autogenic chondral/osteochondral transplantation, have been used for various indications. However, the limited repairing capacity and the potential pitfalls of these techniques cannot be ignored. Increasing evidence has shown promising outcomes from ACI and cartilage transplantation. Nevertheless, the morbidity of autologous donor sites and limited resource of allogeneic bone have considerably restricted the wide application of these surgical techniques. Costal cartilage, which preserves permanent chondrocytes and the natural osteochondral junction, is an ideal candidate for the restoration of cartilage defects. Several in vitro and in vivo studies have shown good performance of costal cartilage transplantation. Although costal cartilage is a classic donor in plastic and cosmetic surgery, it is rarely used in skeletal cartilage restoration. In this review, we introduce the fundamental properties of costal cartilage and summarize costa-derived chondrocyte implantation and costal chondral/osteochondral transplantation. We will also discuss the pitfalls and pearls of costal cartilage transplantation. Costal chondral/osteochondral transplantation and costa-based chondrocytotherapy might be up-and-coming surgical techniques for recalcitrant cartilage lesions.