Human bone marrow mesenchymal stem cell injection in subchondral lesions of knee osteoarthritis: a prospective randomized study versus contralateral arthroplasty at a mean fifteen year follow-up.

PURPOSE: Recently, mesenchymal stem cells (MSCs) have been proposed as potential treatment modalities for knee osteoarthritis. However, indications and long-term results have not been frequently reported. The purpose of this study was to determine whether bone marrow lesion on MRI are predictive of risk progression to total knee arthroplasty during the first ten years after subchondral cell therapy. METHODS: This study included 140 adults aged 65 to 90 years. These 140 patients (mean age 75.4 ± 14.2 years) planned to undergo staged-bilateral total knee arthroplasty (TKA) for medial osteoarthritis, had "comparable" pain in both knees, and accepted randomization of the knees for surgery. They received TKA on one side and a subchondral injection of MSCs (from iliac bone marrow concentrate) on the contralateral knee during the same anaesthetic. The bone marrow graft of 20 cm3 volume (10 cc in the tibia and 10 cc in the femur) contained average 7800 MSCs/mL (range 3120 to 11,560). The baseline volume of bone marrow lesions (BMLs) on the tibia and on the femoral condyle determined on MRI was average 3.4 cm3 (range 0.4 to 6.4 cm3). The risk of subsequent knee arthroplasty due to absence of bone marrow lesions regression as well as osteoarthritis (OA) grade was evaluated with Cox proportional-hazards ratio after control of baseline variables (number of cells injected, age, knee alignment). RESULTS: After treatment with MSCs injection in bone marrow lesions of the subchondral bone, medial femorotibial compartment BML volume experienced regression over 24 months (mean regression 1.5 cm3, range 0.8 to 3.2 cm3). At the most recent follow up (average of 15 years, range 10 to 20 years), a total of 25 (18%) of the 140 patients underwent total knee arthroplasty performed at a mean of ten years (range, 5 to 15 years) after the date of the cell therapy. The overall incidence of knee arthroplasty after cell therapy was 1.19% per person-year which was equivalent to the risk of a revision for a primary TKA in the contralateral knees of the same patient population (21 revisions, corresponding to 1.00% revision per person-year; p = 0.34). After adjusting for confounders, persistent BMLs larger than 3 cm3 after cell therapy was a strong independent risk factor for total knee arthroplasty (hazard ratio HR = 4.42 [95% CI = 2.34 to 7.21]; p < 0.001), regardless of OA grade, with higher risks demonstrated for larger BMLs. Incidence rates of arthroplasty were also higher for young patients and for knees presenting severe malalignment. CONCLUSIONS: This study showed that subchondral bone marrow concentrate (as compared with TKA) had a sufficient effect on pain to postpone or avoid the TKA in the contra lateral joint of patients with bilateral osteoarthritis. Bone marrow lesions were predictive factors for future knee arthroplasty in the knee with subchondral cell therapy at ten years follow-up.

Thoracic computerised tomography scans in one hundred eighteen orthopaedic patients during the COVID-19 pandemic: identification of chest lesions; added values; help in managing patients; burden on the computerised tomography scan department.

PURPOSE: Based on the recent literature, chest computed tomography (CT) examination could aid for management of patients during COVID-19 pandemic. However, the role of chest CT in management of COVID-19 patients is not exactly the same for medical or surgical specialties. In orthopaedic or trauma emergency, abdomen, pelvis, cervical, dorsal, and lumbar spine CT are performed to investigate patients; the result is a thoracic CT scan incorporating usually the thorax; however, information about lung parenchyma can be obtained on this thorax CT, and manifestations of COVID-19 can be diagnosed. The objective of our study was to evaluate this role in orthopedic patients to familiarize orthopaedists with the value and limits of thoracic CT in orthopaedic surgery. MATERIALS AND METHODS: Among the 1397 chest CT scans performed during the pandemic period from 1 March 2020 to 10 May 2020, in two centres with orthopaedic surgery, we selected all the 118 thoracic or chest CT performed for patients who presented to the Emergency Department of the hospital with a diagnosis of trauma for orthopaedic surgical treatment. Thirty-nine of these 118 patients were tested with PCR for the diagnosis of COVID-19 infection. Depending on clinical status (symptomatic or non-symptomatic), the information useful for the orthopaedist surgeon and obtained from the Chest CT scan according to the result of the PCR (gold standard) was graded from 0 (no or low value) to 3 (high value). The potential risks of chest CT as exposure to radiation, and specific pathway were analyzed and discussed. A group of patients treated during a previous similar period (1 March 2018 to 15 April 2018) was used as control for evaluation of the increase of CT scanning during the COVID-19 pandemic. RESULTS: Among the 118 patients with chest CT, there were 16 patients with positive COVID-19 chest CT findings, and 102 patients with negative chest CT scan. With PCR results as reference, the sensitivity, specificity, positive predictive value of chest CT in indicating COVID-19 infection were 81%, 93%, and 86%, respectively (p = 0.001). A useful information for the orthopaedic surgeon (graded as 1 for 71 cases, as 2 for 5 cases, and as 3 for 11 cases) was obtained from 118 chest CT scans for 87 (74%) patients, while the CT was no value in 30 (25%) cases, and negative value in one (1%) case. Roughly 20% of the total number of CT scanner performed over the pandemic period was dedicated to COVID-19, but only 2% were for orthopaedic or trauma patients. However, this was ten times higher than during the previous control period of comparison. CONCLUSION: Although extremely valuable for surgery management, these results should not be overstated. The CT findings studied are not specific for COVID-19, and the positive predictive value of CT will be low unless disease prevalence is high, which was the case during this period.

Ceramic-on-ceramic THA associated with fewer dislocations and less muscle degeneration by preserving muscle progenitors.

BACKGROUND: Dislocation is a common complication after total hip arthroplasty (THA). Although the etiology of dislocation is multifactorial, longer-term changes in muscle such as atrophy may influence the risk of prosthetic dislocation. Biological differences in wear products generated by different bearing surfaces may influence differences in the appearance of periarticular muscle after THA; however, such bearing-associated differences to our knowledge have not been studied in vivo, and few studies have evaluated bearing-associated differences in dislocation risk. QUESTIONS/PURPOSES: (1) Is there a correlation between the postoperative risk of dislocation at revision and the bearing surfaces of the primary arthroplasty? (2) Is there a higher extent of fatty muscle atrophy on CT scan in hips with osteolysis (polyethylene hips) as compared with hips without osteolysis (ceramic-on-ceramic hips)? (3) Are these two abnormalities (bone osteolysis and fatty atrophy) associated with a decrease of mesenchymal stem cells (MSCs) in bone and in muscle? METHODS: We retrospectively evaluated 240 patients (240 hips) who had a THA revision (98% of which, 235 of the 240, were isolated acetabular revisions) and a normal contralateral hip. All patients had received the same implants for the primary arthroplasty (32-mm head) except for bearing surfaces (80 hips with ceramic-on-ceramic, 160 with polyethylene). No differences were noted between the groups in terms of age, sex, body mass index, proportion of patients who had a dislocation after the index arthroplasty but before the revision, and proportion of the patients with stem loosening in addition to acetabular loosening. Indications for revision generally were cup loosening. The revisions in the hips with polyethylene bearings generally had more acetabular bone loss, but the position of the center of the cup and the orientation of the cup were similar after reconstruction in the two groups. Before revision, osteolysis, muscle atrophy, and fatty degeneration were evaluated on CT scan and compared with the contralateral side. Bone muscle progenitors were evaluated by bone marrow MSCs and satellite cells for muscle. At revision, all the hips received the same implants with the same head diameter (32 mm) and a standard liner. Revisions were performed between 1995 and 2005. The followup after revision was at a mean of 14 years (range, 10-20 years) for ceramic revision and 12 years (range, 10-20 years) for polyethylene hips, and there was no differential loss to followup between the groups. RESULTS: More hips with polyethylene liners at the time of index arthroplasty dislocated after revision than did hips with ceramic liners (18% [29 of 160] compared with 1% [one of 80]; odds ratio, 17.5; 95% confidence interval, 2.3363-130.9100; p = 0.005). For the 80 hips with ceramic-on-ceramic, no osteolysis was detected before revision; there was no muscle fatty degeneration of the gluteus muscles on CT scan or histology. For the 160 hips with polyethylene liners, osteolytic lesions on the acetabulum and femur were observed in 100% of the hips. The increased atrophy of the gluteus muscles observed on CT scan correlated with the increase of osteolysis (r = 0.62; p = 0.012). The surgical limbs in the patients with polyethylene hips as compared with ceramic-on-ceramic hips demonstrated a greater reduction in cross-sectional area (respectively, 11.6% compared with 3%; odds ratio, 3.82; p < 0.001) and radiological density (41% [14.1/34.1] compared with 9%; odds ratio, 6.8; p = 0.006) of gluteus muscles when compared with the contralateral normal side. (41% compared with 9%; odds ratio, 6.8; p = 0.006). CONCLUSIONS: Ceramic bearing surfaces were associated with fewer dislocations after revision than polyethylene bearing surfaces. The reasons of the lower rate of dislocation with ceramic-on-ceramic bearings may be related to observed differences in the periarticular muscles (fat atrophy or not) with the two bearing surfaces. LEVEL OF EVIDENCE: Level III, therapeutic study.

Percutaneous injection of bone marrow mesenchymal stem cells for ankle non-unions decreases complications in patients with diabetes.

PURPOSE: Clinical studies in diabetic patients have demonstrated that there is a high incidence of complications in distal tibia and ankle fracture treatments. One strategy to mitigate issues with wound healing and infection in diabetic patients is to use a percutaneous technique in which autologous, bone marrow-derived, concentrated cells are injected at the site of non-unions. METHODS: Eighty-six ankle non-union in diabetic patients were treated with bone marrow mesenchymal stem cells (BM-MSCs) delivered in an autologous bone marrow concentrate (BMC). Clinical outcomes of the 86 diabetic non-union patients treated with BMC were compared with 86 diabetic matched non-unions treated with a standard bone iliac crest autograft. RESULTS: Treatment with BMC promoted non-union healing in 70 among 86 diabetic patients (82.1 %) with a low number of complications. Of the 86 diabetic patients treated with iliac bone graft, 53 (62.3 %) had healing; major complications were observed: 5 amputations, 11 osteonecroses of the fracture wound edge and 17 infections. CONCLUSIONS: In diabetic patients with ankle non-unions, treatment with BM-MSCs from bone marrow concentrate may be preferable in view of the high risks of major complications after open surgery and iliac bone grafting, and improved healing rates compared with standard iliac bone autograft treatment.

Full weight bearing and dynamisation with Limmed® locked plate fixation accelerates bone regeneration in the volume of opening wedge high tibial osteotomy.

PURPOSE: The efficacy of immediate full weight bearing in accelerating bone regeneration after medial opening wedge high tibial osteotomy (HTO) was evaluated in patients operated with the Limmed system (locked plate fixation) that allows dynamisation of the site of the osteotomy. METHODS: A case series of 50 consecutive osteotomies performed with Limmed locked plate fixation for medial opening wedge HTO had full weight bearing immediately after the HTO; they were compared to a case-matched control series of 50 HTOs (50 patients) performed using the same implant without locked screws. Radiographs were observed at 30 days and two, three, four, five and six months after surgery. The osteotomy gap was only partially filled by a medial bone substitute leaving the lateral part unfilled. Bone surface areas of osteotomy planes were quantified and opening volumes were determined applying wedge heights. End points for evaluation included radiographic evidence of bone regeneration in the volume created by the opening of the osteotomy. RESULTS: Statistically significant differences were seen between the groups in terms of radiographic union and radiographic stability between the two groups. Patients of the Limmed group reported a shorter time for union (average four weeks difference) without loss of correction during healing. At the radiographic evaluation, there was a significant increase in osseointegration in the group with weight bearing compared to the control group without weight bearing with increased rate of speed to fill the void volume of the osteotomy. The computed tomography scan of the grafted area at four months after surgery showed no significant difference in the quality of the newly formed bone between the two groups. CONCLUSIONS: The Limmed medial opening wedge HTO system with immediate full weight bearing accelerates bone graft substitute osseointegration and bone healing as compared with controls without full weight bearing.

Long, titanium, cemented stems decreased late periprosthetic fractures and revisions in patients with severe bone loss and previous revision.

PURPOSE: Long, cementless, femoral stem revisions are being used with increasing frequency. There is a relative lack of studies of late fractures after cementless implants, particularly in those patients who had a previous stem revision and are at higher risk for periprosthetic fracture after revision. In this paper, we review risk factors for periprosthetic fracture and revisions of long, cementless, locked stems and report implant survival compared with conventional, cemented, long-stem hip revision arthroplasties in such a group of patients. METHODS: We used data recorded in our institution. Between 1996 and 2002, 85 cementless femoral stem Aura™ (distal locked stem) prostheses were implanted in 85 patients. Of the 85 revisions with long, cementless stems, 32 were performed after one stem revision, 20 after two stem revisions and 12 after three stem revisions. Between 2003 and 2010, 124 femoral revision stems were performed in 124 patients using an extensively long, titanium femoral stem (Ceraver Osteal™). Kaplan-Meier analysis was used to determine implant survival. The Cox regression model was used to study risk factors for reoperation and revision. RESULTS: The increase in stem length corresponded to a mean of 4.5 ± 2.1 femoral canal diameters and was not significantly different (p = 0.02) between the two groups. Cardiopulmonary distress, intraoperative or postoperative complications were not significantly different between the two groups. There was an overall increased risk of pain, periprosthetic fractures and revision for the cementless prostheses compared with the cemented stems. With regard to thigh pain at the last follow-up, most patients (95 %) reported no pain in the cemented group, while 15 % of the cementless group experienced thigh pain under stress and 6 % had incapacitating pain. In the cemented group, stem re-revision was not required in any hip; there was no periprosthetic fracture; five stems had radiological loosening but in the absence of pain were not revised. Among patients of the cementless group, 21 % sustained failure or revision of their interlocked stem with periprosthetic fractures observed in 15 cases; factors which contributed significantly to a higher risk of fracture included the number of previous revisions; the average time between surgery and failure was 3.2 years after one revision, 2.8 years after two revisions, and 1.6 years after three revisions. CONCLUSIONS: The long, cementless, locked stem showed more early complications compared with recementing of long-stem prosthesis. We therefore recommend the use of cemented long stems in patients with severe bone loss and previous revision.

Stand-alone ALIF with integrated intracorporeal anchoring plates in the treatment of degenerative lumbar disc disease: a prospective study on 65 cases.

PURPOSE: ALIF with cages is expected to restore disc height and stabilize the spine promoting fusion, while avoiding damage attributed to rod-pedicle screw fixation. However, it may be related to an increased risk of fusion failure and subsidence. A prospective study was conducted by five investigators across three centers to confirm performance of a PEEK cage for stand-alone ALIF in the treatment of lumbar degenerative disc disease (DDD). METHODS: Sixty-five patients, with back ± leg pain, requiring surgery for DDD, were included. Efficacy and safety were evaluated at 6 weeks, 3, 6, and 12 months post-operatively. Fusion and subsidence were assessed through CT-images at 12-month follow-up. Disc height was measured. Clinical outcomes included back and leg pain (VAS), disability (Oswestry Disability Index), Quality of Life (Short-Form 36), and adverse events. RESULTS: The fusion and the subsidence rates were 96.3 and 2.0 %, respectively. ALIF surgery restored anterior and posterior disc height compared to baseline. There were no device-related serious adverse events, and no revision surgeries. Clinical outcomes improved significantly through 12-month follow-up. CONCLUSION: Safety and efficacy of this stand-alone cage with integrated intracorporeal plates was confirmed through 12 months for treatment of degenerative conditions. The design of the cage and plates may contribute to the decreased subsidence rate observed.

Bone union rate with recombinant human bone morphogenic protein-2 versus autologous iliac bone in PEEK cages for anterior lumbar interbody fusion.

PURPOSE: Autologous iliac crest bone graft (ICBG) is the gold standard material for spinal fusion. Bone graft substitutes, such as recombinant human bone morphogenic protein 2 (rhBMP-2) have been developed to promote spinal fusion and address morbidity issues related to ICBG harvesting. The objective of this study was to compare bone fusion rates after anterior lumbar interbody fusion (ALIF) between ICBG and rhBMP-2 by examining thin-cut computed tomography (CT) images at the one year follow-up. METHODS: Fifty one patients (62 levels) who underwent single- or two-level ALIF via the video-assisted minimally invasive anterior approach in our institution were assessed. Radiolucent cages were inserted in all cases. Each cage has a middle beam delimiting two chambers. Grafting was performed as follows: one chamber was filled with autologous ICBG, and the other chamber was filled with 6 mg of rhBMP-2. Thin-cut CT-scan multiplanar reconstruction analyses were performed to assess the rate and quality of bone fusion at one year of follow-up. RESULTS: Fusion was observed in 55 levels (88.7 %), with significant differences in fusion rates with rhBMP-2 and ICBG (71 % vs. 88.7 %) (P=0.001). Osteogenesis in the rhBMP-2 chamber had a centripetal pattern in all cases, leaving a central void in 97.7 % of cases representing 38.3 % of the surface of its chamber (range 0-80.3 %). In ICBG chambers, graft resorption was present in 44.4 %, representing 9.8 % of the chamber surface (range 0-52.2 %). CONCLUSION: RhBMP-2 was inferior to ICBG in terms of rate and quality of bone fusion in one- or two-level ALIF.

New preclinical porcine model of femoral head osteonecrosis to test mesenchymal stromal cell efficiency in regenerative medicine.

PURPOSE: In order to evaluate new therapeutic approaches to human osteonecrosis of the femoral head (ONFH), this study proposed to improve the existing animal model by developing a new surgically induced pig model. METHODS: First, ONFH was induced with an easy and minimally invasive technique: cryogenic insult with repeated freeze-thaw cycle. Then, to compare and improve the efficacy of this first method, we combined the cryogenic insult to vascular coagulation of the posterior circumflex vessels. RESULTS: Cryoinjury with repeated freeze-thaw cycle alone is sufficient to induce, three weeks postsurgery, a subchondral necrosis as confirmed by magnetic resonance imaging (MRI) and histological analysis. However, a bone regeneration began at four weeks and was complete at eight weeks. To optimise this result, we combined cryoinjury with posterior circumflex vessel coagulation and observed the persistence of ONFH, with progression to collapse at 14 weeks postinduction. CONCLUSIONS: Cryoinjury associated with partial vascular coagulation is sufficient to obtain localised and sustainable necrosis in the subchondral area of the femoral head, reproducing all stages of the human disorder. The co-analysis by MRI and histology allowed us to confirm that the classic T1- and T2-weighted hyposignal regeneration front around a fatty high T1-weighted signal observed by MRI indicate signs of induced osteonecrosis. Our results indicate that our pig model induces all stages of human ONFH, which can be followed by MRI, making it relevant for clinical trials.

Morbidity of graft harvesting versus bone marrow aspiration in cell regenerative therapy.

PURPOSE: Using bone marrow mesenchymal stem cells (MSCs) with aspiration from the iliac crest is commonly used in reconstructive orthopaedic surgery. Because bone marrow aspiration is a percutaneous technique, the morbidity as compared with the classical bone graft should be decreased. METHOD: Therefore in a retrospective review of 523 consecutive cases of bone marrow aspiration performed at the Henri Mondor Hospital from 1990 to 2006 for the treatment of fractures, minor and major complications were identified and compared to the number of complications observed during the same period with 435 classical iliac crest bone graft procedures performed for the same indications of treatment of fractures. Minor complications included superficial infections, superficial seromas, and minor haematomas. Major complications included herniation of abdominal contents through massive bone graft donor sites, vascular injuries, deep infections at the donor site, neurologic injuries, deep haematoma formation requiring surgical intervention or transfusion, and iliac wing fractures. RESULT: Bone marrow aspiration decreased significantly the number of complications as compared with harvesting classical iliac crest bone graft that was associated with significant morbidity. Adverse events were significantly lower (p < 0.01) in the 523 procedures with bone marrow aspiration as compared with the 435 bone iliac crest piece harvesting. This was true for anaemia (16 cases versus 87 cases), for early pain (six versus 152), persistent pain (two versus 21), neuralgia (three versus 11), minor complications (ten versus 56), and major complications (three cases versus 22 cases). CONCLUSION: In our series the number of complications with bone marrow aspiration was ten times less than the complications observed with the classical technique of bone piece harvesting from the iliac crest, and the complications were clearly less severe.

An uncommon case of Mycoplasma hominis infection after total disc replacement.

PURPOSE: Beside mechanical complications, the majority of adverse events after total disc arthroplasty (TDA) are related to the surgical approach. Septic complications are very uncommon and only one previous case has been published. The objective of this article is to describe the clinical circumstances, treatment, and outcomes of septic complication after TDA at L4-L5, involving an uncommon pathogen (Mycoplasma hominis). METHODS: A 38-year-old woman underwent a MobiDisc(®) TDA at L4-L5 level for discogenic pain. One month postoperatively, she complained of acute low back and abdominal pain associated with fever (39 °C). C-reactive protein level was elevated (197 mg/L; normal <5 mg/L) and the white blood cell count was normal (7 × 10(9)/L; normal 4-10 × 10(9)/L). A computerized tomography (CT) showed a left psoas-based retroperitoneal abscess. Treatment consisted of open debridement, drainage and empirical antibiotic therapy. Intraoperative cultures yielded M. hominis after 7 days incubation. Antibiotic therapy was adapted and discontinued after 2 months. The patient had failed to mention earlier that she had been suffering from abnormal vaginal discharge for some time and was using an intrauterine contraceptive device. RESULTS: At 1.5-year follow-up, review confirmed healing of the infection with biological normalization without residual collection, radiolucent lines or osteolysis around the prosthesis at radiographs, CT and MRI. CONCLUSIONS: Mycoplasma hominis can be involved as an extragenital pathogen in musculoskeletal infections. Because its culture and identification are difficult, special media and real-time PCR are required in case of postoperative deep wound infection after anterior lumbar spine surgery, especially in the case of previous genitourinary infections, to decrease the delay in diagnosis and treatment.

Analysis of intraoperative difficulties and management of operative complications in revision anterior exposure of the lumbar spine: a report of 25 consecutive cases.

PURPOSE: After a first anterior approach to the lumbar spine, formation of adhesions of soft tissues to the spine increases the surgical difficulties and potential for iatrogenic injury during the revision exposure. The objective of this study was to identify the intraoperative difficulties and postoperative complications associated with revision anterior lumbar spine procedures in a single institution. METHODS: This is a retrospective review of 25 consecutive anterior revision lumbar surgeries in 22 patients (7 men and 15 women) operated on between 1998 and 2011. Patients with trauma or malignancies were excluded. The mean age of the patients at the time of revision surgery was 56 years (range 20-80 years). The complications were analyzed depending on the operative level and the time between the index surgery and the revision. RESULTS: Six major complications (five intraoperatively and one postoperatively) occurred in five patients (20 %): three vein lacerations (12 %) and two ureteral injuries (8 %), despite the presence of a double-J ureteral stent. The three vein damages were repaired or ligated by a vascular surgeon. One of the two ureteral injuries led to a secondary nephrectomy after end-to-end anastomosis failure; the other necessitated secondary laparotomy for small bowel obstruction. CONCLUSIONS: Anterior revision of the lumbar spine is technically challenging and is associated with a high rate of vascular or urologic complications. Therefore, the potential complications of the procedure must be weighted against its benefits. When iterative anterior lumbar approach is mandatory, exposure should be performed by an access surgeon in specialized centers that have ready access to vascular and urologic surgeons.

Treatment of spinal epidural compression due to hematological malignancies: a single institution's retrospective experience.

PURPOSE: To analyze the neurological and mechanical outcomes in 44 consecutive patients treated for a hematological malignancy with epidural localization to assess the place of surgery in the treatment of this pathology. METHODS: Clinical records, CT and MRI scans of 44 patients with epidural localizations of multiple myeloma or lymphoma treated between 1990 and 2005 were analyzed retrospectively. Neurological status, epiduritis and osteolysis volumes, vertebral collapse, and spinal canal compromise were assessed. The neurological outcome was graded according to Frankel and the mechanical outcome was evaluated on the rate of vertebral collapse. RESULTS: Surgery was performed in 11 patients (25 %) for neurological (n = 9) or mechanical (n = 2) reasons. In five cases, a concomitant biopsy was performed because the etiology of the epiduritis was unknown. Fifteen patients (34.1 %) presented with a neurological deficit secondary to an acute vertebral collapse (n = 4), an epiduritis (n = 7), or both (n = 4). Whatever the treatment (surgical or not), a complete recovery (Frankel E) occurred in 14/15 (93.3 %) after a mean delay of 12 weeks (range 2-24 weeks). During the follow-up, seven collapses occurred. We estimated that a threshold of 30 % of osteolysis was associated with a significant risk of vertebral collapse (P = 0.005). CONCLUSIONS: Hematological malignancies with epidural localization must be treated first medically, even in patients with neurological symptoms. Surgery should be considered only in the cases of acute vertebral collapse, medical treatment failure, or to prevent acute collapse in patients with vertebral osteolysis of more than 30 %.

Benefits of small volume and small syringe for bone marrow aspirations of mesenchymal stem cells.

PURPOSE: Aspirating bone marrow from the iliac crest using small volumes of 1-4 ml with a 10-ml syringe has been historically proposed for harvesting adult mesenchymal stem cells and described as a standard technique to avoid blood dilution. The disadvantage of repeated small aspirations is that there is a significantly increased time to harvest the bone marrow. However, it is not known if a large volume syringe can improve the rate of bone marrow aspiration without increasing blood dilution, thus reducing the quality of the aspirate. We compared the concentrations of mesenchymal stem cells obtained under normal conditions with two different size syringes. METHODS: Thirty adults (16 men and 14 women with a mean age of 49 ± 14 years) underwent surgery with aspiration of bone marrow from their iliac crest. Bilateral aspirates were obtained from the iliac crest of the same patients with a 10-ml syringe and a 50-ml syringe. Cell analysis determined the frequencies of mesenchymal stem cells (as determined by the number of colonies) from each size of syringe. The cell count, progenitor cell concentration (colonies/ml marrow) and progenitor cell frequency (per million nucleated cells) were calculated. All bone marrow aspirates were harvested by the same surgeon. RESULTS: Aspirates of bone marrow demonstrated greater concentrations of mesenchymal stem cells with a 10-ml syringe compared with matched controls using a 50-ml syringe. Progenitor cell concentrations were on average 300 % higher using a 10-ml syringe than matched controls using a 50-ml syringe (p < 0.01). CONCLUSIONS: In normal human donors, bone marrow aspiration from 30 patients demonstrated a reduced mesenchymal stem cell number in aspirates obtained using a larger volume syringe (50 ml) as compared with a smaller volume syringe (10 ml).

Does primary or secondary chondrocalcinosis influence long-term survivorship of unicompartmental arthroplasty?

BACKGROUND: Coexistence of degenerative arthritis and calcium pyrophosphate dihydrate (CPPD) crystals (or radiological chondrocalcinosis) with osteoarthritis (OA) of the knees is frequent at the time of arthroplasty. Several studies suggest more rapid clinical and radiographic progression with CPPD than with OA alone. However, it is unclear whether chondrocalcinosis predisposes to higher risks of progression of arthritis in other compartments. QUESTION/PURPOSES: We questioned whether chondrocalcinosis influences clinical scores, degeneration of other compartments, rupture of the ACL, survivorship, reason for revision, or timing of failures in case of UKA. METHODS: We retrospectively reviewed 206 patients (234 knees) who had UKAs between 1990 and 2000. Of these 234 knees, 85 had chondrocalcinosis at the time of surgery and 63 of the knees subsequently had radiographic evidence of chondrocalcinosis observed during followup. We evaluated patients with The Knee Society rating system and compared function and radiographic progression in the other compartments of patients without and with chondrocalcinosis. RESULTS: The use of conventional NSAIDs, radiographic progression of OA in the opposite femorotibial compartment of the knee, failure of the ACL, and aseptic loosening did not occur more frequently among patients with chondrocalcinosis. The 15-year cumulative survival rates were 90% and 87% for the knees without and with chondrocalcinosis, respectively, using revision to TKA as the end point. CONCLUSION: Our findings show chondrocalcinosis does not influence progression and therefore is not a contraindication to UKA.

High dislocation cumulative risk in THA versus hemiarthroplasty for fractures.

BACKGROUND: Although not all elderly patients with femoral neck fractures are candidates for THA, active, mentally competent, independent patients achieve the most durable functional scores with THA compared with hemiarthroplasty. However, a relatively high frequency of early or late dislocation could reduce the potential benefits with THA. QUESTIONS/PURPOSES: We asked whether the incidence of first-time, recurrent dislocation, and revision differed in patients with hip fractures having THA or hemiarthroplasty. PATIENTS AND METHODS: We retrospectively reviewed 380 patients with hip fractures (380 hips) who underwent THAs between 1995 and 1999, and compared them with 412 patients with hip fractures (412 hips) who underwent hemiarthroplasties between 1990 and 1994. The mean followup was 8 years (range, 1-20 years). RESULTS: THA had a higher early risk of first-time dislocation and a higher late risk: 19 (4.5%) of the 412 hips treated with hemiarthroplasty had at least one dislocation whereas 30 (8.1%) of the 380 hips treated with THA had at least one dislocation. The cumulative number of dislocations at the most recent followup (first time and recurrent dislocations) was 58 (13%) for the 380 THAs and 22 (5%) for the 412 hemiarthroplasties. At the 10-year followup, eight THAs (2%) had revision (six recurrent dislocations, two loosenings), and 42 hemiarthroplasties (10%) had revision (40 acetabular protrusions, one recurrent dislocation). CONCLUSIONS: The risk of revision for recurrent dislocation increases with THA, but it remains lower than the risk of revision for wear of cartilage and acetabular protrusion in hemiarthroplasty. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The natural progression of shoulder osteonecrosis related to corticosteroid treatment.

BACKGROUND: Little is known about the rate and factors of progression of shoulder osteonecrosis (ON) related to corticosteroids. PURPOSE: We retrospectively evaluated 125 patients (215 shoulders) with humeral head ON diagnosed by MRI to determine the delay between corticosteroid treatment and the different stages and factors influencing the progression of the disease. METHODS: Seventy-four of the shoulders had asymptomatic Stage I ON, 58 had asymptomatic Stage II ON, 46 had symptomatic Stage I ON, and 37 had symptomatic Stage II ON. The minimum followup was 10 years (average, 14 years; range, 10-20 years). The delay between the beginning of the corticosteroid treatment and the diagnosis of ON of the humeral head averaged 15 months (range, 6-24 months). RESULTS: We observed partial or total regression on MRI only in patients with asymptomatic Stage I ON. At last followup, pain had developed in 98 (74%) and collapse had occurred in 71 (54%) of the 132 previously asymptomatic shoulders. Of the 83 symptomatic shoulders, 68 (82%) had collapsed at the final followup. The time between diagnosis and collapse averaged 10 years for patients with symptomatic Stage I ON and 3 years for patients with symptomatic Stage II ON. CONCLUSIONS: Stage at initial visit, occurrence of pain, and continuation of peak doses of corticosteroids predicted progression of disease in asymptomatic shoulders, whereas in the symptomatic shoulders, extent and location of the lesion were the main risk factors for progression. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels.

Septic arthritis in adults with sickle cell disease often is associated with osteomyelitis or osteonecrosis.

BACKGROUND: Septic arthritis is a known complication of sickle cell disease (SCD) in children, and the association with osteomyelitis and osteonecrosis has been described. However, it is unclear whether this association applies to adults. QUESTIONS/PURPOSES: We therefore asked whether septic arthritis is a frequent complication in adults with SCD and whether it also is associated with osteomyelitis or osteonecrosis. METHODS: We retrospectively reviewed the charts of 2000 consecutive adult patients diagnosed with SCD and recorded symptoms, select findings during physical examination, laboratory data, and select radiographic CT, and MRI observations. RESULTS: Fifty-nine of the 2000 patients (3%) had septic arthritis, 56 of the 59 patients had hemoglobin SS. Thirty-six of the 59 infections (61%) were in the hip. The most frequent findings were pain, swelling, fever greater than 38.2 degrees C (71% of cases), a leukocyte count exceeding 15,000/mm(3) (range, 7900-32,300/mm(3)), a Westergren sedimentation rate greater than 24 mm/hour, and C-reactive protein exceeding 20 mg/L. Cultures were positive in 96% of the joint aspirates. Staphylococcus and Gram-negative infection predominated; no patients had Salmonella joint infections. Preexisting factors of bacterial arthritis included osteonecrosis (29 patients) and osteomyelitis (37 cases) in childhood. Diabetes, rheumatoid arthritis, glucocorticoids, and immunoparesis related to medical treatment by hydroxyurea were associated comorbidities. CT and MRI confirmed the diagnosis of associated osteonecrosis or osteomyelitis and allowed joint aspiration and detection of soft tissue abscess. CONCLUSIONS: The incidence of septic arthritis in adults with SCD is low, but often is associated with osteomyelitis or osteonecrosis. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Constrained liner in neurologic or cognitively impaired patients undergoing primary THA.

BACKGROUND: THA performed in patients with cognitive deficits or neuromuscular diseases has been associated with a high postoperative dislocation rate. The constrained liner reportedly provides stability in patients with recurrent dislocation. However, achieving stability could be offset by early loosening when used in patients with neurologic diseases. QUESTIONS/PURPOSES: We therefore asked whether constrained liners had a higher risk of loosening when used in primary THA for patients with neurologic diseases. METHODS: We retrospectively reviewed a 144 patients (164 hips) with neuromuscular disease who had a constrained polyethylene insert from 1999 to 2004 and compared them to another 120 patients (132 hips) with neuromuscular disease operated on immediately before this period (from 1994 to 1998) who had a conventional polyethylene insert. RESULTS: Thirty-three (25%) of the 132 hips without a constrained liner were known to have had at least one dislocation and 21 had revision for recurrent dislocation. Ten other hips had revision for loosening of the cup. The survival rate was 82% at 5 years and 77% at 10 years with revision due to recurrent dislocation or loosening of the cup as the endpoint. With a constrained liner, at minimum 5-year followup (mean, 7 years; range, 5-10 years), the incidence of complications, particularly dislocation, was decreased (three dislocations among 164 hips; 2%), with one revision for recurrent dislocation and one revision for loosening. CONCLUSIONS: This constrained acetabular component provides durable protection against dislocation without substantial increased loosening at midterm followup.

Opening wedge tibial osteotomy for large varus deformity with Ceraver resorbable beta tricalcium phosphate wedges.

The results in 53 knees that had been treated by proximal tibial opening-wedge osteotomy for large varus deformity and osteoarthritis of the medial compartment were evaluated after a mean length of follow-up of ten years (range, 8-12 years). We used a porous beta-tricalcium phosphate (beta-TCP) wedge because it is resorbable and osteoinductive. All osteotomies were completely consolidated and complete osseointegration of the remnant of the beta-TCP wedge took place. However, after a mean maximum follow-up of ten years none of the cases showed complete resorption. After ten years, 40 (81%) of the 53 knees had an excellent or good result, and in 13 knees there was recurrent pain for which six had an arthroplasty. Although the results deteriorated with time, time was not the only determinant of the result. Alignment, measured as the hip-knee-ankle angle on radiographs of the whole limb that were made with the patient bearing weight, was also a determinant of long-term results. The best results were obtained in the knees that had a hip-knee-ankle angle of 183-186 degrees. In these knees, there was no pain and no progression of the arthrosis in either the medial or the lateral tibiofemoral compartment. Of the three knees that had an angle of more than 186 degrees, all five had progressive degenerative changes in the lateral compartment. In the undercorrected knees (an angle of less than 183 degrees), the results were less satisfactory, and there was a tendency toward recurrence of the varus deformity and progression of the arthritis of the medial compartment. However, when the correction was insufficient the deterioration was slow. Therefore, proximal tibial osteotomy is a very suitable operation even for patients who have gonarthrosis of the medial compartment and a large varus deformity. Although, a rigidly standardised and precise operative technique is required as well as accurate radiographic measurements of the mechanical axis of the limb because exact postoperative alignment is the prerequisite for the longest possible period of relief of symptoms after osteotomy, and this exact alignment is difficult to obtain for patients with large varus deformity.