Journal of Musculoskeletal Research

Background: Adult articular cartilage has limited potential for healing. A new cell technology in which chondrocytes expanded in monolayer culture are transplanted into the cartilage defect of the knee has been introduced. A scaffold is used to hold tissue to the defect area while it heals. Methods: Sixteen paired, fresh-frozen cadaver knees were used. Full-thickness chondral defects of 2 cm × 3 cm were made on either medial or lateral femoral condyles. The scaffold, made of PGA/PLA foam reinforced by PDS mesh, was implanted into a prepared defect area using three or five PDS/PGA staples as the fixation approach. A custom-made fixation system was used to attach each knee to a material testing machine. Each knee was tested for 10 000 cycles at 1 Hz. Upon completion, knees were examined and rated on a semiquantitative scale for damage of the chondral and meniscal surfaces, and for wear and retention of the scaffold and staples. Findings: Implanted scaffolds were retained fully in defect spaces in all cases. No tearing or peeling of the scaffold was observed. The number of staples used for fixation did not influence the wear or retention of scaffolds and staples. Wearing to the adjacent cartilage or meniscal surfaces was undetectable. Results were similar, regardless of whether the scaffold was located in the medial or lateral condyle. No staple was found loose after 10 000 cycles. Interpretation: Three staples were adequate and five staples were feasible to hold the scaffold for a defect size of 2 cm × 3 cm during continuous passive motion.

The objective of this study was to perform preliminary validation of MRI-based joint contact modeling methodology in the radiocarpal joints by comparison with the results of invasive radiocarpal contact measurements in three cadaver experiments. For each experiment, either Pressurex film or a Tekscan sensor was placed into the radiocarpal joints during a simulated grasp. Computer models were based on magnetic resonance imaging (MRI) of the cadaver specimens without load as well as on images acquired with the same loading used for the direct measurements. Geometric surface models of the radius, scaphoid, and lunate (including cartilage) were constructed from the images acquired without load. The carpal bone motions from the unloaded to the loaded state were determined using three-dimensional (3D) voxel image registration. Cartilage thickness was assumed to be uniform at 1.0 mm with an effective compressive modulus of 4 MPa. Resulting data included peak contact pressure, contact area, and contact force in the radioscaphoid and radiolunate joints. Contact area was also measured directly from MR images acquired with load and compared to model data. Qualitatively, there was good correspondence between the MRI-based model data and experimental data, with consistent relative size, shape, and location of radioscaphoid and radiolunate contact areas. Quantitative comparison of model and experimental data was reasonable, but less consistent. Contact area from the MRI-based model was always similar to the contact area measured directly from the MR images. With additional experiments, we believe that MRI-based joint contact modeling will soon be fully validated in the radiocarpal joints.

Ultrasonography is frequently used to measure the rectus femoris muscle cross-section area, and has been suggested to associate with poor health condition. However, no validation studies have been performed to compare rectus femoris muscle ultrasonography (RFMS) with anatomical planimetry when measuring the muscle cross-sectional area (CSA). This validation study compared the two methods of CSA measurement of unfixed (frozen) and fixed (unfrozen) rectus femoris muscle specimens obtained from elderly human cadavers. Agreement between tests was studied by Bland–Altman analysis. We found a significant difference between planimetry and RFMS of unfixed (frozen) muscle specimens (mean difference, -0.389 cm²; 95% CI, -0.144 to -0.634), p = 0.022. No significant difference was observed between the two methods when measuring fixed (unfrozen) muscle specimens (mean difference, 0.032 cm², 95% CI, -0.007 to -0.070), p = 0.107. In fixed specimens, the 95% limit of agreement between the two methods ranged between 0.12 cm² and -0.06 cm² (<10% deviation); while in unfixed muscle specimens, the range was between 0.28 cm² and -1.06 cm² (~50% deviation). In light of the similar results obtained in fixed specimens, ultrasound is a safe and accurate method of rectus femoris muscle size assessment. In clinical practice, RFMS may be used to detect a decrease in rectus femoris muscle mass, typically associated with malnutrition of the elderly, and may therefore be a simple and practical tool for the screening of malnutrition.

Although uncommon, pubic ramus fractures are described in patients who have undergone total hip arthroplasty (THA). We describe two females with superior ramus pubis insufficiency fractures following THA. We consider the physiological and biomechanical aspects of those fractures, e.g. that the superior ramus pubis has the highest load stress on the pelvis (as has already been proved in a three-dimensional finite element model). Also being discussed are risk factors (intrinsic and extrinsic) for stress fractures and the management of insufficiency fractures. Both women suffered osteoporosis, obesity, and had a semisedentary lifestyle — all of which are known risks factors for insufficiency superior ramus pubis fracture to occur in a location which proved as a "weak link" zone after THA. Many of these fractures are undetected, mainly due to the lack of awareness of medical practitioners who attribute the clinical symptoms to other diseases; however, the differential diagnosis of groin pain within the first years following THA should include pubic ramus insufficiency fractures.

Purpose: To epidemiologically assess the gender-specific relationship between height and radiographic osteoarthritis (OA) of the knee, hand, foot, and cervical spine. Methods: Data collected from men (N = 1090) and women (N = 2441) aged 40 years and older participating in the Clearwater Osteoarthritis Study (1988–current) were used (N = 3531). Physical exams including radiographs were conducted. The Kellgren and Lawrence ordinal scale was used to determine evidence of radiographic OA. Results: There is a modest, albeit consistent, increase in OA prevalence among shorter-stature study subjects at all four sites in women and at two sites in men (hands and cervical spine). Our adjusted findings suggest that shorter stature is a risk factor for OA for the hands, feet, and cervical spine, with odds ratios varying between 1.25 and 1.82. After adjusting for body mass index and age, this relationship maintained statistical significance among women for hand OA. (OR = 1.57; p = 0.0001) and feet OA (OR = 1.41; p - value = 0.009). Curiously, no significant association was indicated between height and knee OA for either gender. Conclusions: Shorter stature appears to be associated with an elevated risk of OA, but particularly so for women. Future epidemiologic studies examining this relationship can offer insight into skeletal growth and development knowledge, thus further elucidating the etiology of OA.

Infections following limb-saving surgeries still happen frequently and are refractory to treatment, even though the treatment of massive bone defects caused by bone resection of bone tumors has improved gradually. Once infections become intractable, they generally result in amputations in spite of all kinds of treatment. We report the case of a patient who developed an intractable infection after limb-saving surgery utilizing a massive frozen autograft and a tumor prosthesis, but whose limb was finally successfully salvaged by multiple surgical interventions. We conclude that continued perseverance in treatment after infections may enable preservation of the limb and restoration of good function.