The terms MSC and MSCs have become the preferred acronym to describe a cell and a cell population of multipotential stem/progenitor cells commonly referred to as mesenchymal stem cells, multipotential stromal cells, mesenchymal stromal cells, and mesenchymal progenitor cells. The MSCs can differentiate to important lineages under defined conditions in vitro and in limited situations after implantation in vivo. MSCs were isolated and described about 30 years ago and now there are over 55,000 publications on MSCs readily available. Here, we have focused on human MSCs whenever possible. The MSCs have broad anti-inflammatory and immune-modulatory properties. At present, these provide the greatest focus of human MSCs in clinical testing; however, the properties of cultured MSCs in vitro suggest they can have broader applications. The medical utility of MSCs continues to be investigated in over 950 clinical trials. There has been much progress in understanding MSCs over the years, and there is a strong foundation for future scientific research and clinical applications, but also some important questions remain to be answered. Developing further methods to understand and unlock MSC potential through intracellular and intercellular signaling, biomedical engineering, delivery methods and patient selection should all provide substantial advancements in the coming years and greater clinical opportunities. The expansive and growing field of MSC research is teaching us basic human cell biology as well as how to use this type of cell for cellular therapy in a variety of clinical settings, and while much promise is evident, careful new work is still needed.

/pdf/mesenchymal-stem-cell-perspective-cell-biology-to-clinical-2twe95ou3n.pdf

Mesenchymal stem cell perspective: cell biology to clinical progress

https://www.seas.upenn.edu/~burdick2/papers/2005-2008/Chung_Advanced%20Drug%20Delivery%20Reviews_2008.PDF

Engineering Cartilage Tissue

Experimental and clinical performance of porous tantalum in orthopedic surgery.

BACKGROUND:

Recent advances in the understanding of the anatomy and function of the acetabular labrum suggest that it is important for normal joint function. We found no available data regarding whether labral refixation after treatment of femoro-acetabular impingement affects the clinical and radiographic results.

METHODS:

We retrospectively reviewed the clinical and radiographic results of fifty-two patients (sixty hips) with femoro-acetabular impingement who underwent arthrotomy and surgical dislocation of the hip to allow trimming of the acetabular rim and femoral osteochondroplasty. In the first twenty-five hips, the torn labrum was resected (Group 1); in the next thirty-five hips, the intact portion of the labrum was reattached to the acetabular rim (Group 2). At one and two years postoperatively, the Merle d'Aubigne clinical score and the Tonnis arthrosis classification system were used to compare the two groups.

RESULTS:

At one year postoperatively, both groups showed a significant improvement in their clinical scores (mainly pain reduction) compared with their preoperative values (p = 0.0003 for Group 1 and p < 0.0001 for Group 2). At two years postoperatively, 28% of the hips in Group 1 (labral resection) had an excellent result, 48% had a good result, 20% had a moderate result, and 4% had a poor result. In contrast, in Group 2 (labral reattachment), 80% of the hips had an excellent result, 14% had a good result, and 6% had a moderate result. Comparison of the clinical scores between the two groups revealed significantly better outcomes for Group 2 at one year (p = 0.0001) and at two years (p = 0.01). Radiographic signs of osteoarthritis were significantly more prevalent in Group 1 than in Group 2 at one year (p = 0.02) and at two years (p = 0.009).

CONCLUSIONS:

Patients treated with labral refixation recovered earlier and had superior clinical and radiographic results when compared with patients who had undergone resection of a torn labrum. Although the results must be considered preliminary, we now recommend refixation of the intact portion of the labrum after trimming of the acetabular rim during surgical treatment of femoro-acetabular impingement.

Treatment of Femoro-Acetabular Impingement: Preliminary Results of Labral Refixation

Although 18F-labeled NaF was the first widely used agent for skeletal scintigraphy, it quickly fell into disuse after the introduction of 99mTc-labeled bone-imaging agents. Recent comparative studies have demonstrated that 18F-fluoride PET is more accurate than 99mTc-diphosphonate SPECT for identifying both malignant and benign lesions of the skeleton. Combining 18F-fluoride PET with other imaging, such as CT, can improve the specificity and overall accuracy of skeletal 18F-fluoride PET and probably will become the routine clinical practice for 18F-fluoride PET. Although 18F-labeled NaF and 99mTc-diphosphonate have a similar patient dosimetry, 18F-fluoride PET offers shorter study times (typically less than 1 h), resulting in a more efficient workflow, improved patient convenience, and faster turnarounds of reports to the referring physicians. With the widespread availability of PET scanners and the improved logistics for the delivery of 18F radiopharmaceuticals, prior limitations to the routine use of 18F-fluoride bone imaging have largely been overcome. The favorable imaging performance and the clinical utility of 18F-fluoride PET, compared with 99mTc-diphosphonate scintigraphy, support the reconsideration of 18F-fluoride as a routine bone-imaging agent.

https://jnm.snmjournals.org/content/49/1/68.full.pdf

Skeletal PET with 18F-Fluoride: Applying New Technology to an Old Tracer

BACKGROUND: In patients with symptomatic hip impingement, surgical resection of the femoral head-neck junction may improve the range of motion and relieve pain. A risk of this procedure is fracture. We evaluated the amount of resection of the anterolateral aspect of the femoral head-neck junction that can be done safely.

METHODS: Cadaveric proximal femoral specimens (fifteen matched pairs) were divided into three groups: 10%, 30%, or 50% of the diameter of one femoral neck was removed, and the contralateral femoral neck was left intact to serve as the control. A compressive load was applied directly to the femoral head. Peak load, stiffness, and energy to fracture were compared among the groups.

RESULTS: The energy to fracture differed significantly (p = 0.0015) among the 10%, 30%, and 50% resection groups. The peak load after the 50% resection was significantly less (p = 0.0025) than that after the 10% or 30% resection. With the numbers available, there was no significant difference in peak load between the 10% and 30% resections.

CONCLUSIONS: Resection of up to 30% of the anterolateral quadrant of the head-neck junction did not significantly alter the load-bearing capacity of the proximal part of the femur. However, a 30% resection significantly decreased the amount of energy required to produce a fracture. Thirty percent should be considered to be the greatest feasible amount of resection because of the change in the pattern of the femoral head-neck response to axial loads that we observed.

Surgical treatment of femoroacetabular impingement. Evaluation of the effect of the size of the resection

Purpose The purpose of this study was to determine if the use of platelet concentrate (PC) and bone plug (BP) does accelerate the healing process in anterior cruciate ligament (ACL) reconstruction. Methods One hundred and eight patients requiring ACL reconstruction were prospectively randomized into 4 groups: control (27 patients), PC (26 patients), BP (28 patients), and a combination of PC and BP (27 patients). Magnetic resonance imaging (MRI) studies were carried out at both 3 and 6 months postsurgery. Maturation of the graft was evaluated at the femoral tunnel using MRI maturation criteria defined by a low-intensity signal, absence of osteoligamentous interface, and no widening of the femoral tunnel. Results Three months after surgery, no differences were found among the groups regarding MRI maturation criteria. Six months postsurgery, 78% of the patients in the control group had a low-intensity signal, while in the PC group the low-intensity signal was present in 100% of the patients ( P = .036). No statistical differences were observed regarding the osteoligamentous interface between the various groups. Finally, tunnel widening was seen in 11% of the patients of the BP group versus 41% of the patients in the control group ( P = .047), but no statistical difference was seen with the other groups. Conclusions The use of PC had an enhancing effect on the graft maturation process evaluated only by MRI signal intensity, without showing any significant effect in the osteoligamentous interface or tunnel widening evolution. The use of a BP effectively prevented tunnel widening. The BP and PC combination did not show a synergic effect as compared to PC or BP individually. Level of Evidence Level II, lesser quality randomized controlled trial.

Effects of platelet concentrate and a bone plug on the healing of hamstring tendons in a bone tunnel.

Background In patients with symptomatic hip impingement, surgical resection of the femoral head-neck junction may improve the range of motion and relieve pain. A risk of this procedure is fracture. We evaluated the amount of resection of the anterolateral aspect of the femoral head-neck junction that can be done safely. Methods Cadaveric proximal femoral specimens (fifteen matched pairs) were divided into three groups: 10%, 30%, or 50% of the diameter of one femoral neck was removed, and the contralateral femoral neck was left intact to serve as the control. A compressive load was applied directly to the femoral head. Peak load, stiffness, and energy to fracture were compared among the groups. Results The energy to fracture differed significantly (p = 0.0015) among the 10%, 30%, and 50% resection groups. The peak load after the 50% resection was significantly less (p = 0.0025) than that after the 10% or 30% resection. With the numbers available, there was no significant difference in peak load between the 10% and 30% resections. Conclusions Resection of up to 30% of the anterolateral quadrant of the head-neck junction did not significantly alter the load-bearing capacity of the proximal part of the femur. However, a 30% resection significantly decreased the amount of energy required to produce a fracture. Thirty percent should be considered to be the greatest feasible amount of resection because of the change in the pattern of the femoral head-neck response to axial loads that we observed.

Surgical treatment of femoroacetabular impingement : Evaluation of the effect of the size of the resection surgical technique

Seventy-five revision total hip arthroplasties (73 patients) performed using an extended greater trochanteric osteotomy for exposure and an extensively porous-coated uncemented stem were reviewed after 2 years (range, 1 to 5). The mean osteotomy length was 14 cm (range, 7 to 19 cm) and fixation was with at least 2 cables. One stem was revised at 4 months for stem subsidence and loosening. Of the remaining 74 osteotomies, 73 healed without further procedures. A single nonunion was reoperated at 4 months and healed. Sixty-eight of 73 osteotomies healed with no migration and 5 did with less than 5 mm of proximal migration of the osteotomy fragment. Complications included 3 intraoperative and 1 postoperative osteotomy fragment fractures. Extended trochanteric osteotomy, executed preserving the fragment's vascularity and fixed with rigid fixation, can be performed with a low rate of complications.

Extended Femoral Osteotomy for Revision of Hip Arthroplasty: Results and Complications

Purpose The goal of this study was to compare open and arthroscopic surgical techniques for "cam-type" femoroacetabular impingement in terms of feasibility and reliability. Methods: We used 5 fresh-frozen cadaver specimens (10 hips). Anteroposterior and cross-table radiographs were taken for each. The head-neck union diameter was measured for each. The amount of bone resection at the anterolateral quadrant of the head-neck union was planned for each, with specific references to width, length, depth, and position. One side was randomly assigned to the open group and the other to the arthroscopic group. Surgical time, position of the osteotomy, and variation of the length, width, and depth of the final osteotomy with respect to the proposed dimensions were compared. Results In all specimens partial resection of the anterior-lateral femoral head-neck junction with improvement of the femoral head-neck offset was accomplished. A statistically significant difference ( P Conclusions When comparing surgical precision, no statistically significant differences were found between the open and arthroscopic procedures in any of the measurements. The depth and width of the osteoplasty were reliably obtained by the arthroscopic technique. However, there was a tendency to underestimate the osteoplasty length with the arthroscopic procedure. Positioning the osteoplasty was also less reliable with the arthroscopic procedure than with the open procedure because of the tendency to place the osteoplasty more posterior and distally than intended. Clinical Relevance Surgical resection of the femoral neck prominence and/or part of the anterolateral neck has been reported to improve femoral head offset and alleviate impingement. This study attempts to document the accuracy of this resection when done arthroscopically compared with an open procedure.

Rodrigo Mardones

Papers

Surgical treatment of femoroacetabular impingement. Evaluation of the effect of the size of the resection

Effects of platelet concentrate and a bone plug on the healing of hamstring tendons in a bone tunnel.

Surgical treatment of femoroacetabular impingement : Evaluation of the effect of the size of the resection surgical technique

Extended Femoral Osteotomy for Revision of Hip Arthroplasty: Results and Complications

Surgical correction of "cam-type" femoroacetabular impingement: a cadaveric comparison of open versus arthroscopic debridement.