Osteonecrosis of the knee - which joint preservation procedures work?

Core decompression is superior to nonoperative management for humeral head osteonecrosis: a systematic review

BACKGROUND

Much of the literature on osteonecrosis has traditionally focused on the hip, which remains the most common site for this disease. The shoulder and the knee are the second most frequently affected sites (both approximately 10% of the incidence). There are a variety of techniques for managing this disease, and it is important to optimize this for our patients. This review aimed to compare the results of core decompression (CD) vs. nonoperative modalities for the treatment of osteonecrosis of the humeral head, including (1) success rate defined as lack of progression to further procedures (shoulder arthroplasty) and no need for further intervention; (2) clinical results (patient-reported pain and functional scores); and (3) radiological outcomes.

METHODS

We queried PubMed and found 15 reports that fit the inclusion criteria for studies concerning the use of CD as well as studies discussing nonoperative treatment for stage I-III osteonecrotic lesions of the shoulder. A total of 9 studies encompassed 291 shoulders that underwent CD analyzed at a mean follow-up of 8.1 years (range, 67 months-12 years), and 6 studies examined 359 shoulders that underwent nonoperative management at a mean follow-up of 8.1 years (range, 35 months-10 years). Outcomes of CD and nonoperative management included success rate, number of shoulders requiring shoulder arthroplasty, and evaluation of several normalized patient-reported outcomes. We also assessed radiographic progression (pre- to postcollapse or further collapse progression).

RESULTS

The mean success rate of CD for avoiding further procedures was 76.6% (226 of 291 shoulders) in stage I through stage III. Stage III shoulders avoided shoulder arthroplasty in 63% (27 of 43 shoulders). Nonoperative management resulted in a success rate of 13%, P < .001. In the CD studies, 7 of 9 showed improvements in clinical outcome measurements compared with 1 of 6 of the nonoperative studies. Radiographically, there was less progression in the CD group (39 of 191 shoulders [24.2%]) vs. the nonoperative group (39 of 74 shoulders [52.3%]) (P < .001).

CONCLUSIONS

Given the high success rate and positive clinical outcomes reported, CD is an effective method for management, especially when compared with nonoperative treatment methods for stage I-III osteonecrosis of the humeral head. The authors believe that it should be used as treatment to avoid arthroplasty in patients who have osteonecrosis of the humeral head.

Surgical Trends for Managing Knee Osteonecrosis: A 2010 to 2020 United States Nationwide Study

BACKGROUND

Knee osteonecrosis (ON) is rare, with an estimated incidence of 0.01-0.17 per 1,000 person years. Our study aimed to do the following: 1) quantify total operative procedures with rates normalized to the United States population; 2) compare arthroplasty versus joint-preserving procedural trends; and 3) determine rates of specific operative techniques/demographics in patients aged <50 versus >50 years.

METHODS

Using a nationwide database, 8,269 patients diagnosed with knee ON underwent surgical treatment from 2010 to 2020. Documented surgical procedures included total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), and core decompression. Primary outcomes included procedural utilization with subanalyses comparing arthroplasty versus joint-preserving procedures, and age-stratified by under/over 50 years. Linear regressions were evaluated for trends in procedural volumes over time.

RESULTS

From 2010 to 2014, 0.54% of all knee procedures were to treat ON compared to 0.71% from 2015 to 2020 (P < .001). Overall rates of TKA (85.4%) and UKA (10.3%) far exceeded rates of joint preserving procedures (4.3%). Comparing 2010-2014 with 2015-2019, joint-preserving procedures proportionally increased (0.7 to 5.0%, P < .001). Patients <50 years had significantly more joint-preserving procedures (19.5 versus 2.7%). Overall, TKA was the most common procedure (7,062; 85.40%), following by UKA 853; 10.32%) and core decompression (354; 4.28%).

CONCLUSION

To our knowledge, this is the first study to characterize surgical trends in management of knee ON. Overall surgical volume for knee ON has continued to increase, outpacing population growth. Patients who have knee ON are most commonly managed with arthroplasty procedures, specifically TKA. Younger aged patients (<50 years) are more likely to undergo joint-preserving procedures, namely core decompression.

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..

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

OBJECTIVE

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.

DESIGN

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.

RESULTS

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%).

CONCLUSIONS

Mid-term clinical outcomes of patients with SONK who underwent HTO and OAT with a relatively large lesion were good.

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

OBJECTIVE

The 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.

DESIGN

Twenty 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.

RESULTS

The 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.

CONCLUSIONS

SF levels of biomarkers of inflammation and cartilage degradation were reduced after HTO with a concomitant BMS procedure, suggesting a biological improvement in SONK.

Treatment options for secondary osteonecrosis of the knee

Knee osteonecrosis is a debilitating progressive degenerative disease characterized by subchondral bone ischemia. It can lead to localized necrosis, tissue death, and progressive joint destruction. For this reason, it is essential to diagnose and treat this disease early to avoid subchondral collapse, chondral damage, and end-stage osteoarthritis, where the only solution is total knee arthroplasty. Three types of knee osteonecrosis have been documented in the literature: spontaneous or primitive, secondary, and post arthroscopy. Spontaneous osteonecrosis is the most common type studied in the literature. Secondary osteonecrosis of the knee is a rare disease and, unlike the spontaneous one, involves patients younger than 50 years. It presents a particular set of pathological, clinical, imaging, and progression features. The management of secondary osteonecrosis is determined by the stage of the disorder, the clinical manifestation, the size and location of the lesions, whether the involvement is unilateral or bilateral, the patient's age, level of activity, general health, and life expectancy. This review aims to present the recent evidence on treatment options for secondary osteonecrosis of the knee, including conservative treatment, joint preserving surgery, and knee replacement.

Autologous Osteochondral Transplantation for Young Patients with Postcollapse Osteonecrosis of the Knee: A Retrospective Cohort Study with an Average 7-Year Follow-Up

BACKGROUND

Only a few studies exist that have assessed the efficacy of autologous osteochondral transplantation (AOT) treatment of osteonecrosis (ON) of the knee. The purpose of this study was to clarify the clinical and radiographic results of AOT performed on young patients with postcollapse ON of the knee.

METHODS

This retrospective study included 14 young patients (6 men, 8 women, mean age 34.71 ± 5.41 years) with stage III knee ON undergoing AOT surgery. Mean follow-up time was 87 ± 10.23 months. The postoperative clinical and radiological evaluations were based on Hospital for Special Surgery (HSS) scores and plain x-rays. Paired t tests were used for the statistical analysis by SPSS software.

RESULTS

Preoperative HSS (mean 66.86 ± 7.49 points) was significantly improved at mean 7 years to a postoperative HSS (mean 87.36 ± 8.63 points) (P < 0.001). The postoperative rangeof motion (ROM; 125.71° ± 4.74°) was not significantly different from the preoperative ROM (126.86° ± 7.13°) (P = 0.626). There was no progression of collapse observed in any knees at the last follow-up. No knees required any reoperations during the follow-up period.

CONCLUSION

Fourteen young patients with local ON of the knee were treated by AOT. No progression of bone collapse was seen and clinical improvement sustained at mean 7 years postsurgery. AOT seems to be a safe technique that can give long-term improvement and durability in young ON patients. However, large-sample and high-quality clinical trials are still needed in the future.

Development of a murine model of ischemic osteonecrosis to study the effects of aging on bone repair

Age at onset is one of the most important predictors of outcome following ischemic osteonecrosis (ON). Currently, there is no well-established animal model to study the effects of age on the repair process following ischemic ON. The purpose of this study was to further advance a murine model of ischemic ON using four age groups of mice to determine the effects of aging on revascularization and bone repair following ischemic ON. Ischemia was surgically induced in the distal femoral epiphysis of four age groups of skeletally immature and mature mice; juvenile (5 weeks), adolescent (12 weeks), adult (22 weeks), and middle age (52 weeks). Mice were euthanized at 2 days or 4 weeks post-ischemia surgery to evaluate the extent of ON, revascularization, and bone repair. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining showed extensive cell death in the epiphysis of all four age groups at 2 days post-ischemia surgery. At 4 weeks, the juvenile mice followed by the adolescent mice had significantly greater revascularization and repair of the necrotic marrow space, increased osteoblast and osteoclast numbers, and increased bone formation rates compared to the adult and middle-age mice. Faster revascularization and bone healing were observed in the skeletally immature mice compared to the skeletally mature mice following ischemic ON. The findings resemble the clinical observation of aging on bone repair following ischemic ON. The mouse model may serve as a useful tool to investigate the mechanisms underlying the age-related impairment of bone repair in adolescent and adult ON and to develop novel therapeutic strategies.

Idiopathic arteriopathy-induced focal osteonecrosis of the femoral head in a young dog

CASE DESCRIPTION

A 15-month-old 6.5-kg (14.3-lb) castrated male mixed-breed dog was evaluated because of a 4-month history of progressive intermittent non-weight-bearing lameness of the left pelvic limb.

CLINICAL FINDINGS

Orthogonal radiography of the hip joints revealed a 4-mm atypical radiolucent lesion on the distal caudomedial aspect of the left femoral head and a disproportionately large-diameter femoral medullary canal with a low canal flare index. Prolonged unresponsiveness to medical management and progressive enlargement of the lesion prompted the recommendation for total hip replacement (THR).

TREATMENT AND OUTCOME

THR was performed to restore pain-free function of the left pelvic limb and normal activity. A circular osteochondral flap was grossly evident on the femoral head. Histopathologic findings for this portion of the bone indicated an arteriopathy-induced focal subchondral osteonecrosis that had resulted in articular surface collapse. The noted idiopathic arteriopathy had disrupted the normal blood supply to the affected area. On reexamination and radiographic evaluation 13 months after THR, the dog appeared to have pain-free function of the affected limb and had returned to normal activity with no reported complications or problems.

CLINICAL RELEVANCE

To the authors' knowledge, this report represented the first description of arteriopathy-induced focal osteonecrosis of the caudomedial aspect of the femoral head and its successful treatment in a young dog. This type of lesion may more commonly be the cause of hip joint osteoarthritis in young dogs than previously recognized because establishing a definitive diagnosis requires early recognition and histologic evaluation before advanced degenerative changes develop that obscure the underlying etiology.

Outcomes of Cemented Total Knee Arthroplasty for Secondary Osteonecrosis of the Knee

BACKGROUND

Secondary osteonecrosis of the knee (SOK) generally occurs in relatively young patients; at advanced stages of SOK, the only viable surgical option is total knee arthroplasty (TKA). We conducted a retrospective study to investigate implant survivorship, clinical and radiographic outcomes, and complications of contemporary cemented bicompartmental TKA with/without patellar resurfacing for SOK.

METHODS

Thirty-eight cemented TKAs in 27 patients with atraumatic SOK, mean age 43 years (17 to 65), were retrospectively reviewed. Seventy-four percent had a history of corticosteroid use, and 18% had a history of alcohol abuse. Patellar osteonecrosis was coincidentally found in six knees (16%), and all were asymptomatic without joint collapse. The mean followup was 7 years (2 to 12). Knee Society Score (KSS) and radiographic outcomes were evaluated at 6 weeks, 1 year, then every 2 to 3 years.

RESULTS

Ninety-two percent had implant survivorship free from revision with significant improvement in KSS. Causes of revision included aseptic tibial loosening (one), deep infection (one), and instability with patellofemoral issues (one). Four of six cases also with patellar osteonecrosis received resurfacing, including one with periprosthetic patellar fracture after minor trauma, with satisfactory clinical results after conservative treatment. None of the unrevised knees had progressive radiolucent lines or evidence of loosening. An unresurfaced patella, use of a stem extension or a varus-valgus constrained prosthesis constituted 18%, 8% and 3%, respectively.

CONCLUSION

Cemented TKAs with selective stem extension in patients with SOK had satisfactory implant survivorship and reliable outcomes. Secondary osteonecrosis of the patella should be carefully evaluated prior to operation.

Team approach: Management of osteonecrosis in children with acute lymphoblastic leukemia

With current treatments for acute lymphoblastic leukemia (ALL), the overall prognosis for survival is favorable. Increasing emphasis is placed on recognizing and managing the long-term consequences of ALL and its treatment, particularly involving osteonecrosis. Early osteonecrosis diagnosis and management may improve outcomes and is best accomplished through coordinated teams that may include hematologic oncologists, radiologists, orthopedic surgeons, physical therapists, and the patient and their family. Magnetic resonance imaging is the "gold standard" for diagnosis of early-stage and/or multifocal osteonecrosis. Treatments for osteonecrosis in ALL patients are risk stratified and may include observation, corticosteroid or chemotherapy adjustment, and pharmaceutical or surgical approaches.

Lateral Unicompartmental knee arthroplasty for a secondary osteonecrosis of the lateral femoral condyle. A case report

Background

Secondary osteonecrosis of the knee is a rare event. There are few reports regarding management of this condition. The aim of the present study is to report treatment outcomes for secondary osteonecrosis of the lateral condyle treated with unicompartmental knee arthroplasty (UKA).

Case presentation

A 54-year-old woman with idiopathic thrombocytopenic purpura, who received low-dosage corticosteroids, complained of knee pain for 5 years and difficulty walking in the last 5 months. Fixed-bearing lateral UKA was performed under general anesthesia combined with midthigh saphenous nerve block. The patient could walk without ambulation aid shortly after the operation and achieved satisfactory knee joint function at the 6-week follow-up. The knee society score (KSS) increased from 68 to 91. The follow-up period was up to 1 year. There was no pain, loosening, or fracture of the prosthesis at the latest follow-up.

Conclusions

This case study demonstrates successful management of secondary osteonecrosis of the lateral femoral condyle is possible with a fixed bearing lateral UKA. Early diagnosis, rigorous indication, and appropriate surgical techniques were critical to maximizing prosthesis stability in lateral UKA.

Medulloscopy-Assisted Surgery for Osteonecrosis of the Knee Following Treatment for Adolescent Leukemia: Mid-term Results

BACKGROUND

This study aimed to introduce the medulloscopy-assisted autologous bone graft for osteonecrosis of the knee following adolescent leukemia treatment and to report the mid-term clinical and radiological results.

MATERIALS AND METHODS

We retrospectively reviewed records of eight consecutive knees in six patients with extensive osteonecrosis of the distal femoral condyles, from 2013 to 2015. All patients were treated with autologous bone grafts using medulloscopy. We evaluated functional and objective Knee Society Score (KSS) pre- and postoperatively. Clinical and radiological outcomes were evaluated at the last follow-up.

RESULTS

The mean age of the patients at the time of surgery was 21.5 years. The mean follow-up period was 45 months. No additional surgery was required during the follow-up period. The mean objective KSS significantly increased from 60.6 points (range 55-65) to 90.0 points (range 70-95), postoperatively (p < 0.001). The mean functional KSS significantly improved from 48.8 points (range 45-55) to 90.0 points (range 80-100) postoperatively (p < 0.001). No patients had progression of collapse of the femoral condyles at the final follow-up. At the final follow-up, the onset of minimal osteoarthritis was seen in two knees, with a Kellgren-Lawrence grade 1.

CONCLUSION

Medulloscopy-assisted bone grafting can be an effective treatment option for early symptomatic osteonecrosis of knee following treatment for adolescent leukemia.

Reliable outcomes and survivorship of primary total knee arthroplasty for osteonecrosis of the knee

AIMS

Knee osteonecrosis in advanced stages may lead to joint degeneration. Total knee arthroplasty (TKA) for osteonecrosis has traditionally been associated with suboptimal results. We analyzed outcomes of contemporary TKAs for osteonecrosis, with particular emphasis on: survivorship free from aseptic loosening, any revision, and any reoperation plus the clinical outcomes, complications, and radiological results.

PATIENTS AND METHODS

In total, 156 patients undergoing 167 primary TKAs performed for osteonecrosis between 2004 and 2014 at a single institution were reviewed. The mean age at index TKA was 61 years (14 to 93) and the mean body mass index (BMI) was 30 kg/m² (18 to 51) The mean follow-up was six years (2 to 12). A total of 110 TKAs (66%) were performed for primary osteonecrosis and 57 TKAs (34%) for secondary osteonecrosis. Overall, 15 TKAs (9%) had tibial stems, while 12 TKAs (7%) had femoral stems. Posterior-stabilized designs were used in 147 TKAs (88%) of TKAs. Bivariate Cox regression analysis was conducted to identify risk factors for revision and reoperation.

RESULTS

Survivorship free from aseptic loosening, any revision, and any reoperation at ten years was 97% (95% confidence interval (CI) 93 to 100), 93% (95% CI 85 to 100), and 82% (95% CI 69 to 93), respectively. No factors, including age, sex, BMI, primary versus secondary osteonecrosis, stem utilization, and constraint, were identified as risk factors for reoperation. Four TKAs (2%) underwent revision, most commonly for tibial aseptic loosening (n = 2). Excluding revisions and reoperations, there was a total of 11 complications (7%), with the most common being a manipulation under anaesthesia (six TKAs, 4%). Mean Knee Society Scores (Knee component) significantly improved from 57 (32 to 87) preoperatively to 91 (49 to 100) postoperatively (p < 0.001). No unrevised TKAs had complete radiolucent lines or radiological evidence of loosening.

CONCLUSION

Contemporary cemented TKAs with selective stem utilization for osteonecrosis resulted in durable survivorship, a low complication rate, and reliable improvement in clinical outcomes. Cite this article: Bone Joint J 2019;101-B:1356-1361.

Osteochondral allograft in a patient with avascular necrosis of the knee secondary to lupus

Joint preservation surgery is accepted in cases of secondary osteonecrosis of the knee without joint collapse. However, there is no consensus on the best treatment: debridement and drilling, or use of auto- or allograft. The author describes a clinical case with 15 years of evolution where allogeneic osteochondral graft was used in the treatment of osteonecrosis of the lateral femoral condyle in a young woman with systemic lupus. In spite of having other options and of the results reported in the literature, the functional evaluation 15 years later presented excellent results, with total autonomy of the patient for daily life and work tasks, indicating that the option for osteochondral allograft may be a good solution.

Use of autologous bone marrow stem cell implantation for osteonecrosis of the knee in sickle cell disease: a preliminary report

Background

The purpose of our study was to evaluate safety, feasibility and clinical results of bone marrow mononuclear cell (BMC) implantation for early-stage osteonecrosis of the knee (OK) secondary to sickle cell disease.

Methods

Thirty-three SCD patients (45 knees) with OK treated with BMC implantation in the osteonecrotic lesion were clinically and functionally evaluated through the American Knee Society Clinical Score (KSS), Knee Functional Score (KFS) and Numeric Rating Scale (NRS) pain score. MRI and radiographic examinations of the knee were assessed during a period of five years after intervention.

Results

No complications or serious adverse event were associated with BMC implantation. From preoperative assessment to the latest follow-up, there was a significant (p < 0.001) improvement of clinical KSS (64.3 ± 9.7, range: 45–80 and 2.2 ± 4.1, range: 84–100, respectively), KFS (44.5 ± 8.0, range: 30–55 and 91.6 ± 5.8, range: 80–100, respectively) and reduction of NRS pain score (6.7 ± 1.2, range: 4–9 and 3.4 ± 1.0, range: 2–5, respectively). In total, 87% of patients (29/33) consistently experienced improvements in joint function and activity level as compared to preoperative score. No patient had additional surgery following BMC implantation. Radiographic assessment showed joint preservation and no progression to subchondral collapse at most recent follow-up.

Conclusions

The technique of BMC implantation is a promising, relatively simple and safe procedure for OK in SCD patients. Larger and long-term controlled trials are needed to support its clinical effectiveness.

Trial registration

ClinicalTrials.gov NCT02448121. Retrospectively registered 19 May 2015.

Reliable outcomes and survivorship of unicompartmental knee arthroplasty for isolated compartment osteonecrosis

Aims

Primary (or spontaneous) and secondary osteonecrosis of the knee can lead to severe joint degeneration, for which either total or unicompartmental arthroplasty may be considered. However, there are limited studies analyzing outcomes of unicompartmental knee arthroplasties (UKAs) for osteonecrosis involving an isolated compartment of the knee. The aims of this study were to analyze outcomes of UKAs for osteonecrosis with specific focus on 1) survivorship free of any revision or reoperation, 2) risk factors for failure, 3) clinical outcomes, and 4) complications.

Patients and Methods

A total of 45 patients underwent 46 UKAs for knee osteonecrosis between 2002 and 2014 at our institution (The Mayo Clinic, Rochester, Minnesota). Twenty patients (44%) were female; the mean age of the patients was 66 years, and mean body mass index (BMI) was 31 kg/m². Of the 46 UKAs, 44 (96%) were medial UKAs, and 35 (76%) were fixed-bearing design. Mean mechanical axis postoperatively was 1.5° varus (0° to 5° varus); 41 UKAs (89%) were performed for primary osteonecrosis. Mean follow-up was five years (2 to 12).

Results

Survivorship free of any revision in the cohort was 89% (95% CI 77 to 99) and 76% (95% CI 53 to 99) at five and ten years, respectively. In patients undergoing UKA for primary osteonecrosis survivorship free of any revision was 93% (95% CI 83 to 100)at both five and ten years. Secondary osteonecrosis was a significant risk factor for poorer survivorship free of any revision or reoperation (hazard ratio 7.7, p = 0.03). Three medial UKAs (6.5%) were converted to total knee arthroplasties (TKAs): two for lateral compartment degeneration and one for development of lateral osteonecrosis. No implants were revised for loosening, fracture, or wear. Knee Society scores improved from a mean of 60 (44 to 72) preoperatively to a mean of 94 postoperatively (82 to 100) (p < 0.001). There were no surgical complications.

Conclusion

When done for primary osteonecrosis of the knee, UKA resulted in reliable clinical improvement, minimal complications, and durable estimated implant survivorship free of revision at ten years. UKA done for secondary osteonecrosis was substantially less durable at mid-term follow-up. Progression of knee degeneration, rather than implant failure or loosening, was most common indication for conversion to TKA. Cite this article: Bone Joint J 2018;100-B:450-4.

Subchondral stem cell therapy versus contralateral total knee arthroplasty for osteoarthritis following secondary osteonecrosis of the knee

PURPOSE

Total knee arthroplasty (TKA) implanted in patients with secondary osteonecrosis (ON) related to corticosteroids have relatively poor outcome (20% revision rate) at a mean follow-up of only eight years. With the hypothesis that subchondral bone marrow injection might improve knees in these patients, we evaluated 30 patients who had bilateral knee osteoarthritis with severe joint space narrowing and received TKA in one knee and subchondral bone marrow concentrate injection in the contralateral knee.

MATERIAL AND METHODS

A prospective randomized controlled clinical trial was carried out in 60 knees of 30 patients (mean age 28 years, 18-41) who presented bilateral osteoarthritis secondary to knee ON related to corticosteroids in relation with different severe medical conditions. During the same anesthesia, one knee received TKA; for the other knee, a bone marrow graft containing an average of 6500 MSCs/mL (counted as CFU-F, range 3420 to 9830) was delivered to the subchondral bone of the femur and tibia. The length of anesthesia related to each procedure (bone marrow aspiration and subchondral injection of concentrated bone marrow versus total knee arthroplasty) was measured. Peri-operative outcomes, morbidity, complications, and safety of the two procedures were compared. Subsequent admissions for revision surgery were identified. At the most recent follow-up (average of 12 years, range 8 to 16 years), clinical outcomes of the patient (Knee Society score) were obtained along with radiological imaging outcomes (MRIs for knees with subchondral bone marrow injection).

RESULTS

Anesthesia related to the TKA side was longer than for the cell therapy group. Medical and surgical complications were more frequent after TKA. A higher number of thrombophlebitis was observed on the side with TKA (15%) versus none on the side with cell therapy (0%). At the most recent follow-up (average of 12 years, range 8 to 16 years), six (out of 30) TKA knees needed subsequent surgery versus only one with cell therapy. The Knee Score had improved and remained similar in the TKA and cell therapy groups (respectively 80.3 points ± 11 versus 78.3 ± 23); 21 patients preferred the knee with cell therapy and 9 preferred the knee with TKA. Knees with cell therapy had improvement on cartilage and bone marrow lesions observed at the site of bone marrow subchondral injection.

CONCLUSIONS

Subchondral autologous bone marrow concentrate was an effective procedure for treating young patients with knee osteoarthritis following secondary ON of the knee related to corticosteroids with a lower complication rate and a quicker recovery as compared with TKA.

The biological basis for concentrated iliac crest aspirate to enhance core decompression in the treatment of osteonecrosis

Core decompression is a surgical procedure that is capable of salvaging the patient's own natural joint, if the operation is performed in the early stages of osteonecrosis, in which the articular surface has not collapsed. The addition of concentrated cells, aspirated from the iliac crest, to the core tract has been shown to enhance the viability of the femoral head, although large, prospective, randomized, blinded multicentre studies are lacking. The rationale for adding these cells to the core decompression tract is to provide osteoprogenitor and vascular progenitor cells to the area of decompressed dead bone, in order to facilitate tissue regeneration and repair. It has become increasingly evident that vast discrepancies exist in different series in regard to the criteria for patient selection, the surgical technique of core decompression, the methods for harvesting, processing, and injecting the cells, and the methodology for determining success or failure in a specific patient cohort. This paper reviews the salient points relevant to the treatment of osteonecrosis by core decompression with addition of concentrated iliac crest aspirates and poses important questions regarding the future successful application of this technique.

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

PURPOSE

To evaluate the effects of osteochondral autograft transplantation (OAT) mosaicplasty as a concomitant procedure with opening-wedge valgus high tibial osteotomy (HTO) for spontaneous osteonecrosis of the medial femoral condyle (MFC) on clinical outcomes and cartilage status in comparison with bone marrow stimulation (BMS) by drilling, and to assess the relation between lesion size and postoperative cartilage status.

METHODS

Fifty-eight patients with spontaneous osteonecrosis of the MFC were treated with opening-wedge HTO and a concomitant procedure of BMS (28 patients) or OAT (30 patients). Clinical evaluation was carried out using the Knee Society Score at postoperative 2 years. Postoperative status of articular cartilage was assessed by arthroscopy according to the International Cartilage Repair Society (ICRS) grade at the time of plate removal.

RESULTS

The Knee Society Score objective score and function score were improved at postoperative 2 years compared with preoperative value in both groups, but no significant difference was found between the 2 groups. According to the ICRS overall repair grade, cartilage status was rated as normal or nearly normal (ICRS overall score ≥8) in 41% of the BMS group and 90% of the OAT group. The results suggested that cartilage repair in OAT was significantly better than that in BMS (P = .0015). Furthermore, the BMS group revealed that repair with normal or nearly normal was observed in all less than 4 cm² of lesion size, whereas the OAT group exhibited that repair with normal or nearly normal was independent of lesion size.

CONCLUSIONS

This study suggested that OAT is superior to BMS as a concomitant procedure with opening-wedge valgus HTO for spontaneous osteonecrosis of the MFC in the success of cartilage repair. However, clinical outcomes were not significantly different between these 2 procedures. When treating the lesion larger than 4 cm² by joint-preserving surgery, OAT mosaicplasty is recommended as a concomitant procedure with HTO.

LEVEL OF EVIDENCE

Level III, therapeutic case-control study.

Can a biomimetic osteochondral scaffold be a reliable alternative to prosthetic surgery in treating late-stage SPONK?

BACKGROUND

This study aimed to assess the reliability of the Maioregen® biomimetic osteochondral scaffold (Finceramica Faenza SpA, Faenza, Italy) as a salvage and joint-preserving procedure in the treatment of late-stage osteonecrosis of the knee.

METHODS

Eleven active patients aged under 65years and presenting with clinical and radiological signs of SPONK were treated with Maioregen®. All were clinically evaluated pre-operatively and yearly thereafter for a minimum of two years. Subjective IKDC and Lysholm Knee Scale scores were used to assess clinical outcome. A VAS scale served to quantify pre-operative pain and post-operative pain. Activity levels were evaluated pre-operatively and at follow-up using the Tegner Activity Scale.

RESULTS

Subjective IKDC (40±15.0 to 65.7±14.8 (mean±SD)) and Lysholm Knee Scale (49.7±17.9 to 86.6±12.7 (mean±SD)) scores improved significantly from pre-operative evaluation (p<.01). VAS scores decreased from a pre-operative mean (±SD) of 6.3±2.5 to 1.6±2.7 at two years. The Tegner Activity Scale showed no significant differences between pre-injury and two-year follow-up. Two out of the 11 patients were symptomatic at 18months post implant and progressed to condylar collapse. These patients required total knee arthroplasty.

CONCLUSIONS

Use of a biomimetic scaffold can be a valid option in the surgical treatment of SPONK in relatively young active patients. Indeed, this surgical technique, originally developed for osteochondritis dissecans, has been found to give good clinical results at medium-term follow-up of late-stage osteonecrosis treatment and could postpone or even avoid the need for joint replacement procedures.

Treatment of Secondary Osteonecrosis of the Knee With Local Debridement and Osteoprogenitor Cell Grafting

Secondary osteonecrosis of the knee (SOK) affects young individuals with chronic diseases and corticosteroid use. We report a series of young patients in whom the osteonecrotic lesion was openly debrided, and concentrated bone marrow osteoprogenitor cells (OPCs) harvested from the iliac crest were placed in the defect. Twelve patients (fourteen knees) have undergone debridement and grafting of distal femoral osteonecrotic lesions. Age at surgery averaged 23 years. Follow-up averaged 5 years. None of the patients have undergone further surgery, or were taking medications for ipsilateral knee pain. Knee Society Score and Knee Function Score averaged 87 and 85 respectively. The technique of open debridement and osteoprogenitor cell grafting for SOK is relatively simple, efficacious, has low morbidity, and does not preclude future interventions.

Osteonecrosis of the Knee After Anterior Cruciate Ligament Reconstruction: A Report of 5 Cases

Background:

Anterior cruciate ligament (ACL) reconstruction is performed commonly, with a low risk of complication. Osteonecrosis of the knee is a potentially devastating condition and has been observed both spontaneously and after meniscectomy, although osteonecrosis has not been described as a complication after ACL reconstruction.

Purpose:

To describe the development of osteonecrosis of the knee in 5 patients after arthroscopic ACL reconstruction.

Study Design:

Case series; Level of evidence, 4.

Methods:

This study involved 5 patients (mean age, 33.2 years) who developed osteonecrosis of the knee after ACL reconstruction. A retrospective chart review was performed to identify clinical characteristics and surgical factors present in each of the 5 cases.

Results:

In 4 cases, the pathologic changes were present in both the medial and lateral femoral condyles, with isolated lateral condyle changes in the other case. The mean time to diagnosis was 11.6 months. These patients underwent an average of 1.8 additional surgical procedures after the diagnosis of osteonecrosis.

Conclusion:

Osteonecrosis of the knee is a rare outcome after ACL reconstruction. We are unable to identify clear risk factors for the development of this complication, although we hope the presentation of these cases will help promote the identification of other cases in future studies.

An Unusual Metallic Foreign Body inside the Knee Medial Femoral Condyle

Foreign bodies in the knee joint are uncommon, particularly those not related to surgical procedures. In this paper, we present a case of an intraosseous metallic foreign body situated in the medial femoral condyle for one year, causing pain, which was removed with complete resolution of the symptoms.