Core decompression for juvenile osteonecrosis

Effects of bone marrow-derived mesenchymal stem cell transplantation in piglet Legg-Calve-Perthes disease models: a pilot study

This preliminary study investigated the efficacy and safety of bone marrow-derived mesenchymal stem cell transplantation in a piglet Legg-Calve-Perthes disease (LCPD) model. The LCPD model was induced in two Landrace piglets (6- and 7-week-old, weighing 12 and 17 kg, respectively) by ligaturing the femoral neck. In the first piglet, the natural LCPD course was observed. In the second piglet, 4 weeks after ligaturing the femoral neck, simple medium and medium containing 2.44 × 10 7 bone marrow-derived mesenchymal stem cells were transplanted into the right and left femoral heads after core decompression, respectively. Plain radiographs were obtained every 4 weeks, and the epiphyseal quotient was calculated by dividing the maximum epiphysis height by the maximum epiphysis diameter. The piglets were sacrificed at 14 weeks postoperatively. The femoral heads were extracted and evaluated grossly, pathologically, and by using computed tomography. The transplanted cell characteristics were evaluated using flow cytometry. Flattening of the epiphysis was observed in both femoral heads of the first piglet and only in the right hip of the second piglet. The epiphyseal quotients immediately and at 14 weeks postoperatively in the right femoral head of the second piglet were 0.40 and 0.14, respectively, while those of the left femoral head were 0.30 and 0.42, respectively. Hematoxylin and eosin staining did not reveal physeal bar or tumor cell formation. The transplanted cells were 99.2%, 65.9%, 18.2%, and 0.16% positive for CD44, CD105, CD29, and CD31, respectively. Core decompression combined with bone marrow-derived mesenchymal stem cell transplantation prevented epiphyseal collapse.

Does transepiphyseal drilling and closure of the greater trochanter in early Legg-Calve-Perthes disease improve natural history?

PURPOSE

There is no consensus regarding treatment of Legg-Calve-Perthes disease (LCPD). The most common sequel of the disease is coxa breva and overgrowth of the greater trochanter (GT). Our purpose was to examine the effectiveness of transepiphyseal drilling combined with closure of the GT apophysis in patients with LCPD.

METHODS

During 2013-2018, we treated 16 consecutive cases of LCPD. Average age was 7.5 (range 6-10) years; nine patients were in early fragmentation, five in late fragmentation and one in reossification stages. Treatment protocol included hip arthrography, percutaneous drilling of the femoral head epiphysis, percutaneous tenotomy of adductor longus and epiphysiodesis of the GT apophysis.

RESULTS

Mean follow-up was 38 months. One patient was lost to follow-up. All patients had a limp prior to surgery. However, at latest follow-up, 10/15 patients had no limp, 11 patients had substantial improvement in hip range of motion. On radiographs, nine patients had Stulberg type 1-2, one type 3 and five type 4-5. There was no change in the epiphysio-trochanteric distance in any patient. Eight out of nine patients treated in the early fragmentation stage had good clinical and radiographic outcome. Most patients treated in late fragmentation stage had Stulberg 4-5 hip and required additional procedures.

CONCLUSIONS

Based on our preliminary experience, our protocol can be effective in the treatment of patients with LCPD in the initial or early fragmentation stages by improving the clinical and radiographic outcomes of the disease. This minimally invasive approach does not compromise any future treatment options.

LEVEL OF EVIDENCE

IV.

Minimally Invasive Necrotic Bone Washing Improves Bone Healing After Femoral Head Ischemic Osteonecrosis: An Experimental Investigation in Immature Pigs

BACKGROUND

Ischemic osteonecrosis of the femoral head produces necrotic cell debris and inflammatory molecules in the marrow space, which elicit a chronic inflammatory repair response. The purpose of this study was to determine the effects of flushing out the necrotic cell debris and inflammatory proteins on bone repair in a piglet model of ischemic osteonecrosis.

METHODS

Osteonecrosis of the femoral head of the right hindlimb was induced in 12 piglets by tying a ligature tightly around the femoral neck. One week after the surgery, 6 animals were treated with a percutaneous 3-needle bone washing procedure and non-weight-bearing (NWB) of the right hindlimb (wash group). The total saline solution wash volume was 450 mL per femoral head. Serial wash solutions were collected and analyzed. The remaining 6 animals were treated with NWB only (NWB group). At 8 weeks after the surgery, the femoral heads were assessed using radiography, micro-computed tomography (micro-CT), and histological analysis. In addition, we compared the results for these piglets with our published results for 6 piglets treated with multiple epiphyseal drilling (MED) plus NWB without bone washing (MED group).

RESULTS

Necrotic cells and inflammatory proteins were present in the bone wash solution collected 1 week after ischemia induction. The protein and triglyceride concentrations decreased significantly with subsequent washing (p < 0.005). At 8 weeks after ischemia induction, the wash group had a significantly higher bone volume than the MED or NWB group (p < 0.0001). Histological bone-formation measures were also significantly increased in the wash group compared with the MED group (p = 0.002) or NWB group (p < 0.0001) while macrophage numbers were significantly decreased in the wash group.

CONCLUSIONS

The percutaneous 3-needle procedure flushed out cell debris and inflammatory proteins from the necrotic femoral heads, decreased osteoclasts and macrophages, and increased bone formation following induction of ischemic osteonecrosis.

CLINICAL RELEVANCE

We believe that this is the first study to investigate the concept of washing out the necrotic femoral head to improve bone healing. The minimally invasive procedure may be useful to improve the necrotic bone environment and bone repair following ischemic osteonecrosis.

A Comparison of Transphyseal Neck-Head Tunneling and Multiple Epiphyseal Drilling on Femoral Head Healing Following Ischemic Osteonecrosis: An Experimental Investigation in Immature Pigs

BACKGROUND

Two operative procedures are currently advocated to stimulate the necrotic femoral head healing in children with Legg-Calve-Perthes disease: transphyseal neck-head tunneling (TNHT) and multiple epiphyseal drilling (MED). The purpose of this study was to compare the bone healing and physeal function after treatment with TNHT or MED in a piglet model of ischemic osteonecrosis.

METHODS

Eighteen piglets were induced with osteonecrosis by surgically placing a ligature tightly around the right femoral neck. One week later, the piglets were assigned to 1 of 3 treatment groups (n=6/group): (1) local nonweight bearing only (NWB), (2) TNHT plus NWB, or (3) MED plus NWB. The unoperated left femoral heads were used as normal controls. The animals were euthanized at 8 weeks after osteonecrosis induction. Histologic, histomorphometric, radiographic, microcomputed tomography (CT), and calcein-labeling assessments were performed. Statistical analysis included a 1-way ANOVA.

RESULTS

Micro-CT analyses showed higher femoral head bone volume in the MED group compared with the TNHT and the NWB groups (P<0.01). The MED group had a higher mean trabecular number (P<0.001) and new bone formation (P=0.001) based on calcein-labeling parameters compared with the TNHT and the NWB groups. In addition, the osteoclast number per bone surface was lower in the MED group compared with the NWB group (P=0.001). Histologic and micro-CT assessments of the proximal femoral physis revealed a larger physeal disruption at the site of physeal drilling in the TNHT group compared with the MED group. However, no significant differences in physeal elongation (P=0.61) and femoral neck length (P=0.31) were observed between the treatment groups.

CONCLUSIONS

MED produced a higher bone volume and stimulated greater bone formation than the TNHT or the NWB alone. Both procedures did not produce a significant physeal growth disturbance during the study period.

CLINICAL RELEVANCE

This preclinical study provides evidence that MED produces more favorable bone healing than the TNHT in a large animal model of Legg-Calve-Perthes disease.

A comparison of subtraction MRI with the standard contrast-enhanced imaging in Perthes' disease

PURPOSE

Perthes' disease (PD) results from loss of blood supply to the hip and can progress to femoral head deformity. MRI in the early course of the disease can provide data on the initial extent of infarct. Vascularity of the femoral head is assessed by gadolinium-enhanced MRI (contrast MRI), which may be improved by the digital subtraction technique (subtraction MRI). We hypothesized that gadolinium-enhanced MRI without subtraction was comparable with subtraction MRI in depicting the femoral head perfusion.

METHODS

In all, 34 patients (34 hips) with unilateral PD had gadolinium-enhanced MRI as part of a prospectively randomized study. Nine patients had three MRIs, 15 had two and ten had a single MRI. Measurement of perfusion of the femoral head (MRI perfusion index) was obtained using digital image analysis on all the MRIs, including both before and after subtraction. A paired sample t-test was performed to compare the measurements.

RESULTS

The mean age of the patients was 8.9 years (sd 1.6). At the time of diagnosis, the subtraction MRI did not elicit a statistically significant difference in MRI perfusion index measurements when compared with the contrast MRI (p = 0.19). The same findings were found when including all patients at various stages of the disease (p = 0.30). Qualitatively, although some subtraction MRI images showed superior delineation of epiphysis, there are no significant differences throughout the whole series.

CONCLUSION

Although the current literature supports the increasing role of the subtraction MRI for PD management, our study proposed that the contrast MRI without subtraction technique appears adequate in assessing femoral head perfusion.

LEVEL OF EVIDENCE

Level I - Diagnostic study.

The Pathogenesis and Treatment of Legg-Calvé-Perthes Disease

Legg-Calvé-Perthes disease is a childhood hip condition in which the blood supply to the capital femoral epiphysis is interrupted, causing osteonecrosis and chondronecrosis that lead to progressive deformity of the femoral head and secondary degenerative osteoarthritis in later life. The etiology of Legg-Calvé-Perthes disease remains unclear, with both biological and mechanical factors playing important roles in the pathogenesis of the condition. The treatment of Legg-Calvé-Perthes disease remains controversial but is dependent on several salient factors, including the age at clinical onset, the extent of epiphyseal involvement, the stage of the disease, and the degree of femoral head deformity. The literature supports operative containment treatment in the early stage of disease. Such treatment has led to improved femoral head sphericity with better patient outcomes in multicenter prospective cohort studies. The number of hips that need to be treated operatively in order to achieve a modest treatment effect remains high. Multicenter prospective cohort studies have shown that 6 to 7 patients need to be managed to create 1 spherical femoral head that would not have otherwise occurred.

Long-term Outcome of Multiple Small-diameter Drilling Decompression Combined with Hip Arthroscopy versus Drilling Alone for Early Avascular Necrosis of the Femoral Head

BACKGROUND

Avascular necrosis of femoral head (AVNFH) typically presents in the young adults and progresses quickly without proper treatments. However, the optimum treatments for early stage of AVNFH are still controversial. This study was conducted to evaluate the therapeutic effects of multiple small-diameter drilling decompression combined with hip arthroscopy for early AVNFH compared to drilling alone.

METHODS

This is a nonrandomized retrospective case series study. Between April 2006 and November 2010, 60 patients (98 hips) with early stage AVNFH participated in this study. The patients underwent multiple small-diameter drilling decompression combined with hip arthroscopy in 26 cases/43 hips (Group A) or drilling decompression alone in 34 cases/55 hips (Group B). Patients were followed up at 6, 12, and 24 weeks, and every 6 months thereafter. Radiographs were taken at every follow-up, Harris scores were recorded at the last follow-up, the paired t-test was used to compare the postoperative Harris scores. Surgery effective rate of the two groups was compared using the Chi-square test.

RESULTS

All patients were followed up for an average of 57.6 months (range: 17-108 months). Pain relief and improvement of hip function were assessed in all patients at 6 months after the surgery. At the last follow-up, Group A had better outcome with mean Harris' scores improved from 68.23 ± 11.37 to 82.07 ± 2.92 (t = -7.21, P = 0.001) than Group B with mean Harris' scores improved from 69.46 ± 9.71 to 75.79 ± 4.13 (t = -9.47, P = 0.037) (significantly different: t = -2.54, P = 0.017). The total surgery effective rate was also significantly different between Groups A and B (86.0% vs. 74.5%; χ2 = 3.69, P = 0.02).

CONCLUSION

For early stage of AVNFH, multiple small-diameter drilling decompression combined with hip arthroscopy is more effective than drilling decompression alone.

Combined with Bone Marrow-Derived Cells and rhBMP-2 for Osteonecrosis after Femoral Neck Fractures in Children and Adolescents: A case series

Osteonecrosis of the femoral head (ONFH) following femoral neck fractures is a rare, yet severe, disorder in children and adolescents. This study evaluated the effectiveness of core decompression (CD) combined with implantation of bone marrow-derived cells (BMDC) and rhBMP-2 for osteonecrosis of femoral head (ONFH) after femoral neck fractures in children and adolescents. This study included 51 patients, aged 11.4-18.1 years, with ARCO stages I-III ONFH after femoral neck fractures between 2004 and 2010. The hips were divided into two groups based on whether the lateral pillar of the femoral head (LPFH) was preserved: LPFH and non-LPFH groups. All patients were followed up clinically and radiographically for a minimum of 5 years. 44 patients (86.3%) had improved clinical outcome. Radiologically, 9 of the 51 hips (17.6%) exhibited collapse onset or progression of the femoral head or narrowing of the hip joint space, and one patient in the non-LPFH group required hip arthroplasty due to the worsened syndrome. The technique provided an effective therapeutic option for children and adolescents with ONFH following femoral neck fractures. It relieves hip pain and prevents the progression of osteonecrosis in young patients lasting more than 5 years after surgery.

Management of Perthes' disease

The main complication of Perthes' disease is femoral head deformation. Evidence from the literature highlights two important factors related to the cause and timing of this complication. (1) Extrusion of the femoral head appears to be a major factor that leads to femoral head deformation. (2) Deformation of the femoral head occurs in the latter part of the stage of fragmentation. The likelihood of preventing femoral head deformation is over 16 times higher if extrusion is reversed or prevented by the early stage of fragmentation than if done later. Several treatment options have been described in children who present later in the course of the disease but the outcomes of all these measures do not compare with those of early intervention.

Female patients with late-onset legg-calvé-perthes disease are frequently gymnasts: is there a mechanical etiology for this subset of patients?

BACKGROUND

The cause of Legg-Calvé-Perthes disease (LCPD) is unknown. We have observed a relatively high prevalence of female gymnasts presenting with LCPD. The purpose of this study was to determine: (1) the percentage of LCPD patients exposed to high-level gymnastics training, (2) the demographics of this subset of patients, and (3) their clinical outcomes.

METHODS

Several adolescent female gymnasts presented to our clinic with recent-onset LCPD. We reviewed our cases to discern the prevalence and treatment of the disorder in this patient cohort. From 1999 to 2010, 572 patients were evaluated for a diagnosis of LCPD at our tertiary referral center. Clinical records were retrospectively reviewed. Of those, 13 patients had a history of gymnastics participation with 8 patients (all females) having competitive participation.

RESULTS

For females aged 10 years and older presenting with LCPD, 7 of 9 patients (78%) were involved in high-level competitive gymnastics. These patients had disease onset between 10 and 12 years of age (mean, 11 y). Competitive gymnasts represented 6.6% (8 of 120) of females with LCPD and 1.4% (8 of 572) of all patients evaluated with LCPD during the study period. Only 1 of 111 females below 10 years with LCPD participated in competitive gymnastics (χ, P<0.0001).Patients underwent a variety of treatments. Two patients underwent nonoperative treatment, and the remainder underwent surgical management. All 7 gymnasts had a Stulberg IV result. In the nongymnast group of females 10 years and older, there were 1 Stulberg III result and 1 Stulberg IV result.

CONCLUSIONS

At our center, competitive gymnasts comprise >75% of the female patients over the age of 10 who presented with late-onset LCPD. Results in general were poor. Further studies are needed to explore the association between the physical demands of advanced gymnastic training and the development of LCPD in this subset of patients.

LEVEL OF EVIDENCE

IV, case series.

Mesenchymal stem cells in osteoarticular pediatric diseases: an update

Cellular therapy has gained an increasing popularity in recent years. Mesenchymal stem cells (MSCs) have the potential to differentiate into bone, cartilage, or fat tissue. In recent studies, these cells have also shown healing capability by improving angiogenesis and preventing fibrosis, which could have a role in tissue repair and tissue regeneration. Preclinical and clinical orthopedic studies conducted in the adult population support the use of MSCs for bone-healing problems, early stages of osteonecrosis, and local bone defects. Only a few published studies support the use of MSCs in pediatric osteoarticular disorders, probably due to the unknown long-term results of cellular therapy. The purpose of this review is to explain the mechanism by which MSCs could exhibit a therapeutic role in pediatric osteoarticular disorders.