Patellar fractures account for approximately 1% of all fractures. Open reduction and internal fixation is recommended to restore extensor continuity and articular congruity. However, complications such as nonunion and symptomatic hardware, still exist. Furthermore, there is a risk of re-fracturing of the healed bone during the removal of the implants. Magnesium (Mg), a biodegradable metal, has elastic moduli and compressive yield strength that are comparable to those of natural bone. Our previous study showed that released Mg ions enhanced fracture healing. However, Mg-based implants degrade rapidly after implantation and lead to insufficient mechanical strength to support the fracture. Microarc oxidation (MAO) is a metal surface coating that reduces corrosion. We hypothesized that Mg pins, with or without MAO, would enhance fracture healing radiologically, mechanically, and histologically, while MAO would decrease degradation of Mg pins.

Patellar fracture was performed on forty-eight 18-week-old female New Zealand White rabbits according to established protocol. Briefly, the patella is osteotomized transversely and a tunnel (1.1mm) was drilled longitudinally through the two bone fragments. A pin (1 mm, stainless steel, Mg, or MAO-Mg) was inserted into the tunnel. The reduced construct was stabilized with a figure-of-eight band wire (⊘ 0.6 mm stainless steel wire). Cast immobilization was applied for 6 weeks. The rabbits were euthanized at week 8 and 12 post-operation. Microarchitecture and mechanical properties of the repaired patella were analyzed with microCT and tensile testing respectively. Histological sections of the repaired patella were stained. To evaluate the effect of the MAO treatment on degradation rate of Mg pin, the volume of the Mg pins in the patella was measured with microCT.

At week 8, both Mg and Mg-MAO showed higher ratio of bone volume to tissue volume (BV/TV) than the control while there was no significant different between Mg and Mg-MAO. At week 12, Control, Mg, and Mg-MAO groups showed enlarged patella when compared to the normal patella. Tissue volume (TV) and bone volume (BV) of the patella in Mg and Mg-MAO were larger than those in the Control group. However, the Control had higher ratio of bone volume to tissue volume (BV/TV), TV density, and BV density than Mg and Mg-MAO. Tensile testing showed that the mechanical properties of the repaired patella (failure load, stiffness, ultimate strength, and energy-to-failure) of Mg and Mg-MAO were higher than that of the control at both week 8 and week 12. Histological analysis showed that there was significant new bone formation in the Mg and Mg-MAO group compared with the Control group at week 8 and 12. The degradation rate of the MAO-coated Mg pins was significantly slower than those without MAO at week 8 but no significant difference was detected at week 12.

Mechanical, microarchitectural, and histological assessments showed that Mg pins, with or without MAO, enhanced fracture healing of the repaired patella compared to the Control. MAO treatment enhanced the corrosion resistance of the Mg pins at the early time point.

Summary Statement

This study demonstrated that Sclerostin monoclonal antibody (Scl-Ab) enhanced bone healing in the rat osteotomy model. Scl-Ab increased callus size, callus bone volume fraction, rate of callus bone formation and fracture callus strength.

Purpose: Harvesting of iliac crest graft for spinal fusions is associated with a number of patients reporting residual pain at the harvest site. Various interventions have been proposed to minimize the pain associated with this. The purpose of this study was to evaluate the efficacy of intra-operative infiltration of morphine into the iliac crest harvest site for reduction of postoperative pain.

Method: A double-blinded, placebo controlled study was performed comparing intraoperative infiltration of 5mg of morphine (treatment) vs. saline (placebo) into the iliac crest harvest site for patients undergoing elective spinal surgery. Patients with myelopathy, excessive preoperative opiod use (60mg equivalent morphine/day or more), or multilevel (greater than 3 levels) spinal surgery were excluded. Postoperative administration of morphine (recovery room and PCA) was standardized. Numerical pain scores specific for the iliac crest site were determined in the immediate postoperative period and at 3, 6 and 12 months. Ad hoc power analysis demonstrated that 36 patients would be able to detect a clinically significant difference of 2.4 points on a 10 point numerical pain scale (alpha = 0.05, power = 80%).

Results: 37 patients were randomized and evaluated with a minimum of one year follow-up. The groups were similar in baseline age, gender and comorbidity. There was no significant difference between groups in total use of postoperative morphine during the first 24 hours (treatment: 320mg +/− 268mg, placebo: 293mg +/− 182mg, p = 0.73). There was no significant difference in iliac crest activity pain scores at 1 year (treatment: 1.7 +/− 3.0, placebo: 1.1 +/− 2.4, p = 0.48) or at any of the earlier time points. The proportion of patients with moderate to severe iliac crest pain at one year follow-up was the same between both groups.

Conclusion: This study has demonstrated that there are no additional benefits for the use of intra-operative infiltration of morphine into the iliac crest harvest site during spinal fusions.

Back pain is a complex problem affecting the majority of the population at some point in their life. This cross-sectional study evaluated patients presenting to a tertiary spine clinic with a primary complaint of back pain for modifiable lifestyle factors which may be associated with their back pain. Patients were also asked if any of these lifestyle factors had been addressed by primary care practitioners prior to referral to the spine surgeon’s office.

The purpose of this cross-sectional study is to evaluate the modifiable lifestyle factors which may be associated with back pain in patients presenting to a tertiary spine clinic with a primary complaint of back pain and to compare these lifestyle factors with the general population. A secondary objective is to determine whether patients with back pain were given any instructions with regard to modifiable lifestyle factors by their primary care practitioner.

Consecutive patients presenting to the orthopaedic spine surgery clinic at the Ottawa Hospital – Civic Campus are asked to complete a questionnaire upon presentation to the surgeon’s clinic and prior to their visit with the surgeon. Data being collected includes Body Mass Index, smoking history, physical activity history, perceived stress, and disability. Information is also being collected on sources of information about back pain including instructions given by primary care practitioners (physician, chiropractor, physiotherapist, massage therapist, acupuncturist, naturopath, and other). Data will be analyzed to determine the difference in modifiable risk factors between patients presenting to the spine surgery clinic and the general population. Data will also be tabulated for numbers of patients being given information on modifiable lifestyle factors by primary care practitioners.

To date fifty-two patients have completed the questionnaire. A significant difference has been noted between the number of morbidly obese (BMI > 30) patients presenting to the clinic and the general population. It has been noted that less than 20% of primary care physicians have talked about lifestyle modification with their patients prior to referring them to a spine surgeon.

It will be important to know what modifiable lifestyle risk factors this group of patients possesses and which of these modifiable lifestyle risk factors are actually being addressed by primary care practitioners prior to referral to spine surgeons.

The current waiting list for an appointment with a spine surgeon at the Ottawa Hospital is six to eighteen months. If surgeons can help primary care practitioners address some modifiable lifestyle factors with their patients prior to their referral, waiting times may be reduced or at the very least made more comfortable for patients.