Articular cartilage has poor repair potential and the tissue formed is mechanically incompetent. Mesenchymal stromal cells (MSCs) show chondrogenic properties and the ability to re-grow cartilage, however a viable human model for testing cartilage regeneration and repair is lacking. Here, we describe an ex vivo pre-clinical femoral head model for studying human cartilage repair using MSCs.

Human femoral heads (FHs) were obtained following femoral neck fracture with ethical permission/patient consent and full-depth cartilage wells made using a 3mm biopsy punch. Pancreas-derived mesenchymal stromal cells (P-MSC) were prepared in culture media at ~5000 cells/20µl and added to each well and leakage prevented with fibrin sealant. After 24hrs, the sealant was removed and medium replaced with StemPro^TM chondrogenesis differentiation medium. The FHs were incubated (37^oC;5% CO₂) for 3wks, followed by a further 3wks in standard medium with 10% human serum with regular medium changes throughout. Compared to wells with medium only, A-MSCs produced a thin film across the wells which was excised en-block, fixed with 4% paraformaldehyde and frozen for cryo-sectioning.

The cell/tissue films varied in thickness ranging over 20-440µm (82±21µm; mean±SEM; N=3 FHs). The thickness of MSC films abutting the cartilage wells was variable but generally greater (15-1880µm) than across the wells, suggesting an attachment to native articular cartilage. Staining of the films using safranin O (for glycosaminoglycans; quantified using ImageJ) was variable (3±8%; mean±SEM; N=3) but in one experiment reached 20% of the adjacent cartilage. A preliminary assessment of the repair tissue gave an O'Driscoll score of 10/24 (24 is best).

These preliminary results suggest the ex vivo femoral head model has promise for studying the capacity of MSCs to repair cartilage directly in human tissue, although optimising MSCs to produce hyaline-like tissue is essential.

Supported by the CSO (TCS/17/32).

Power production in the terminal stance phase is essential for propelling the body forward during walking and is generated primarily by ankle plantarflexion. Osteoarthritis (OA) of the ankle restricts joint range of motion and is expected to reduce power production at that ankle. This loss of power may be compensated for by unaffected joints on both the ipsilateral and contralateral limbs resulting in overloading of the asymptomatic joints. Total ankle arthroplasty (TAA) has been shown to reduce pain and has the potential to restore range of motion and therefore increase ankle joint power, which could reduce overloading of the unaffected joints and increase walking speed. The purpose of this study was to test the hypothesis that ankle OA causes a loss of power in the affected ankle, compensatory power changes in unaffected lower limb joints, and that TAA will increase ankle power in the repaired ankle and reduce compensatory changes in other joints.

One hundred and eighty-three patients (86 men, 97 women with average ages 64.1 and 62.4 years respectively) requiring surgical intervention for ankle OA were prospectively enrolled. Implant selection of either a fixed (INBONE or Salto Talaris) or mobile (STAR) bearing implant was based on surgeon preference. Three-dimensional kinematics and kinetics were collected prior to surgery and one year post-operatively during self-selected speed level walking using an eight-camera motion capture system and a series of force platforms. Subject walking speed and lower extremity joint power during the last third of stance at the ankle, knee, and hip were calculated bilaterally and compared before and after surgical intervention across the entire group and by implant type (fixed vs. mobile), and gender using a series of ANOVAs (JMP SAS, Cary, NC), with statistical significance defined as p < 0 .05.

There were no gender differences in age, walking speed, or joint power. All patients increased walking as a result of surgery (0.87 m/s±0.26 prior to surgery and 1.13 m/s±0.24 after surgery, p < 0 .001) and increased total limb power. Normalized to total power (which accounts for changes in speed and distribution of power production across joints), prior to surgery the affected ankle contributed 19%±10% of total power while the unaffected ankle contributed 42%±12% (P < 0 .001). After surgery, the affected ankle increased to 25%±9% of total power and the unaffected ankle decreased to 38%±9% of total (P < 0.001). Other joints showed no significant power changes following surgery. Fixed bearing implants provide greater surgical ankle power improvement (61% versus 29% increase, p < 0 .002). Much of that change was due to the fact that those that received fixed-bearing implants had significantly lower walking speed and power before surgery.

Ankle OA reduced ankle power production, which was partially compensated for by the unaffected ankle. TAA increases walking speed and power at the affected ankle while lowering power production on the unaffected side. The modifications in power production could lead to increased physical activity and reduced overloading of asymptomatic joints.

Since the introduction of national guidelines in 2009 encouraging the use of total hip arthroplasty (THA) to treat intracapsular neck of femur fractures there has been no population-based studies into the surgical outcomes for this indication. This study aims to calculate the complication rates for THA when performed for a fractured neck of femur and compare them to THA performed for primary osteoarthritis in the same population.

The Scottish Arthroplasty Project was used to identify all THAs performed in Scotland for neck of femur fracture and osteoarthritis between 1st of January 2009 and 31st December 2014. Dislocation, infection and revision rates at 1 year were calculated.

The rate of dislocation, infection and revision at 1 year were all significantly increased among the fracture neck of femur cohort. In total 44046 THAs were performed, 38316 for OA and 2715 for a neck of femur fracture. 2.1% of patients (n=57) who underwent a THA for a neck of femur fracture suffered a dislocation in the 1st year postoperatively, compared to 0.9% (n=337) when the THA was performed for osteoarthritis. Relative Risk of dislocation: 2.3870 (95% C.I. 1.8077–3.1252, p value <0.0001). Relative Risk of infection: 1.4561 (95% C.I. 1.0496–2.0200, p value 0.0245) Relative Risk of revision: 1.4807 (95% C.I. 1.0308–2.1268, p value 0.0336).

This is the first time a dislocation rate for THA performed for a neck of femur fracture has been calculated for an entire population. As the number of THAs for neck of femur fracture increases this dislocation rate will have clinical implications.

Aim: While ankle fractures are not thought of as osteoporotic fractures, poor bone quality presents difficulties in fracture fixation of the distal fibula. We measured the relation between bone density of the distal fibula and the insertional and stripping torques of screws used for fibular plating using two different plate configurations.

Methods: Ten paired fresh cadaveric ankles (average age: 81.7 years) were used for the study. Computed tomography scanning with phantoms of known density was used to determine the bone density along the distal fibula. A standard small fragment seven-hole one-third tubular plate was applied to the lateral surface of the fibula, with three proximal bicortical cortical screws and two distal unicortical cancellous screws. A posterior plate in which all five screws were cortical and achieved bi-cortical purchase was subsequently applied to the same bones such that the screw holes did not overlap. A torque sensor was used to measure the torque of each screw during insertion (Ti) and then stripping (Ts).

Results: Mean bone density of the distal fibula is significantly less than in the shaft (p< 0.01). There was a moderate positive correlation between torque and bone density for the lateral plates (r2=0.6 for Ti and r2=0.7 for Ts), and a weak correlation for the posterior plates (r2=0.4 for Ti and Ts). For the proximal three screws, there was no significant difference in average Ti and Ts between lateral and posterior plates. For the distal two screws, posterior plates had significantly higher values for both Ti and Ts than the lateral plates (p< 0.01).

Conclusions: The insertion and stripping torques of the screws in the distal fibula were significantly higher and less dependent on bone density with a posterior plate than with a lateral plate.

Aims and methods

To compare the mechanical stability of an intramedullary (IM) screw with two crossed interfragmentary compression screws for fixation of the 1st MTPJ in ten pairs of cadaveric feet. One foot underwent fixation with two crossed 4.0-mm cannulated cancellous screws. The contralateral foot was fixed with an IM 1.6-mm Kirschner wire and an IM 6.5-mm partially threaded cancellous lag screw. A plantar-to-dorsal load was applied to the distal end of the proximal phalanx at a rate of 1 mm/sec. Failure was defined as gross actuator displacement of 5 mm. Stiffness was defined as the slope of the force versus deformation curve between 10 and 60 N. Strength was defined as the load at failure. The differences in stiffness and strength parameters between the two fixation techniques were checked for significance (P < 0.05) with a paired t-test.

Results

The intramedullary MTP joint fixation was significantly stiffer (18.7 ± 10.1 N/mm) than control group fixation (10.2 ± 6.1 N/mm). Similarly MTP joint fixation in the IM group was stronger (149.2 ± 88.2 N) than that of the control group (100.2 ± 70.8 N), but this was not significant (P = 0.07).

Conclusions

The IM technique resulted in a stronger stiffer fixation when compared with the standard crossed lag screw technique.

We retrospectively reviewed 52 children treated for tuberculosis of the knee in the 21-year period 1979 to 1999.

The mean age at which the condition was diagnosed was 5.3 years (8 months to 13 years). The median duration of symptoms was four weeks (1 month to 3 years). All patients presented with swelling, mainly owing to synovitis. Pain was a symptom in only two thirds of patients.

Using Kerri and Martini’s classification of radiological appearances, 33 knees were stage I (osteopoenia), 15 stage II (osteopoenia with erosions), two stage III (joint space narrowing) and two stage IV (joint space narrowing with anatomical disorganisation). All knees had either positive histology (caseating granuloma) and/or a positive culture for tuberculosis.

Treatment was with rifampicin, isoniazide and pyrazinamide for nine months. No synovectomy was done. Of the 48 knees with stage-I and stage-II disease, 22 were immobilised for at least three months and 26 actively mobilised.

At a mean follow-up of five years (2 to 16 years), the results were classified according to Wilkinson. All stage-I and stage-II knees had an excellent result (full range of motion) or good result (more than 90° of flexion). Stage-III and stage-IV knees had a fair result (less than 30°of flexion) or poor result (ankylosis). In stage-I and stage-II knees, immobilisation did not affect outcome.

In the same period, 25 knees with a non-specific histology and negative culture presented the problem of the differential diagnosis between tuberculosis and particular juvenile rheumatoid arthritis (JRA). Of these 17 were subsequently diagnosed as JRA. A histological study assessed the value of synovial lining (SLC) hyperplasia. The sensitivity of SLC hyperplasia for JRA was only 53%. Synovial biopsies from 10 joints with tuberculosis (positive histology or culture) were subjected to the polymerase chain reaction test. The sensitivity was only 40% for tuberculosis.