D.S.K. Choon

Platelet-rich plasma (PRP) enhances bone healing in non-united critical-sized defects: a preliminary study involving rabbit models.

INTRODUCTION The use of bone grafts in treating non- or delayed unions as the result of large bone loss is well established. However, despite good outcomes, the time to achieve complete union is still considerably long. To overcome this problem, the use of platelet-rich plasma (PRP) has been advocated albeit with varying success. To determine the true effectiveness of PRP in treating non-/delayed unions, a study was conducted using (n=12) rabbit models. METHODS AND MATERIALS Critical-sized defects measuring 2cm created in the midshaft of the right rabbit tibias were stabilised using 2.7-mm small fragment plates. A spacer placed in the defects to create a delay in bone union was replaced at 3 weeks with artificial bone grafts (Coragraft®), with or without PRP. The operated limbs were radiographed following the defect creation and at 3, 7 and 11 weeks (at sacrifice). Bone healing and histological changes were later assessed and scored using the appropriate grading systems. Four groups were compared for quality of healing: (group-A) control group, that is, no PRP or Coragraft; (group-B) PRP; (group-C) Coragraft; and (group-D) PRP and Coragraft. RESULTS Group-D demonstrated the best bone healing based on radiological, histological and gross findings (Kruskall-Wallis: p<0.05). Group-C had significantly higher scores than group-B, whilst group-A had significantly lower scores than all other groups (Mann-Whitney U: p<0.05). CONCLUSION The use of PRP with bone graft significantly improves the quality of bone healing. However, the use of PRP without bone substitute does not provide adequate repair tissue and, therefore, provides little benefit when used independently.

Comparison of low-dose rofecoxib versus 1000 mg naproxen in patients with osteoarthritis. Results of two randomized treatment trials of six weeks duration.

Objective : To compare the efficacy and safety of rofecoxib 12.5 mg once daily to naproxen 500 mg twice daily in patients S 40 years of age with knee or hip osteoarthritis (OA). Methods : Two identical 6-week, randomized, double-blind studies were conducted (1 in Africa, Australia, Europe, Canada, Mexico, & South America; 1 in Asia). Primary endpoints were pain walking on a flat surface, patient global assessment of response to therapy, and investigator global assessment of disease status. Results : Overall, 944 patients participated. For all efficacy endpoints, treatment effects for rofecoxib and naproxen were comparable and seen at the first measures of efficacy. Both compounds were generally well-tolerated, with an improved gastrointestinal safety profile for rofecoxib versus naproxen. Conclusions : In these studies, rofecoxib 12.5 mg once daily (the lowest indicated dose) and naproxen 500 mg twice daily showed similar treatment effects in OA patients. Rofecoxib and naproxen were generally well tolerated.

Early results of prosthetic hip replacement for femoral neck fracture in active elderly patients.

Purpose. To evaluate the short-term clinical and functional outcomes of total hip arthroplasty performed for physiologically active elderly patients with Garden type-3 or -4 femoral neck fracture. Methods. Records of 47 consecutive patients (40 female, 7 male) with type-3 or -4 femoral neck fracture (Garden classification) who underwent cemented total hip arthroplasty at our hospital during January 1999 to December 2002 were reviewed. Radiological and clinical (Harris functional hip score and Oxford hip score) assessments of 38 patients were measured with a mean follow-up period of 21 months (range, 4–48 months). Results. The mean age of the 47 patients was 75 years (range, 62–89 years). Records of 9 patients were excluded because of death, lost to follow-up, and development of deep infection that necessitated implant removal and excision arthroplasty. The mean Harris hip score of the 38 patients was 83 (range, 59–97), whereas the mean Oxford hip score was 25.2 (range, 14–33). Pain in the hips was absent in 30 patients, 6 had slight pain occasionally, and 2 patients had mild-to-moderate hip discomfort. No signs of aseptic loosening or change in implant position were noted on radiographic assessment. Two cases of dislocation were reduced by closed reduction. Two patients had deep wound infection and were treated with debridement, implant removal, and conversion to girdle stone. Conclusion. This short-term study showed that total hip arthroplasty for femoral neck fracture had good postoperative results in functional hip and pain scores. More attention should be paid to coexisting medical illness (e.g. diabetes mellitus, hypertension, and ischaemic heart disease) and prevention of infection.

The treatment of open tibial fractures and of tibial non-union with a novel external fixator

We report the results of external fixation in 29 patients treated for tibial fractures and tibial non-union using a novel multi axial external fixator (MAXX) followed prospectively until bony union. The results of treatment were classified according to the Association for the Study and Application of the Method of Ilizarov (ASAMI). Overall, 13 patients had excellent bone results; 13 had good bone results; two had fair bone results, and 1 patient had poor bone results. Regarding functional results, 21 patients had excellent results; 6 obtained good results; none had fair results, and two had poor results. Acute patients did better functionally than chronic patients. This fixator is safe and versatile, although the indications for its use are very specific.

Biocompatibility and Toxicity of Poly(vinyl alcohol)/N,O-Carboxymethyl Chitosan Scaffold

The in vivo biocompatibility and toxicity of PVA/NOCC scaffold were tested by comparing them with those of a biocompatible inert material HAM in a rat model. On Day 5, changes in the blood parameters of the PVA/NOCC-implanted rats were significantly higher than those of the control. The levels of potassium, creatinine, total protein, A/G, hemoglobulin, erythrocytes, WBC, and platelets were not significantly altered in the HAM-implanted rats, when compared with those in the control. On Day 10, an increase in potassium, urea, and GGT levels and a decrease in ALP, platelet, and eosinophil levels were noted in the PVA/NOCC-implanted rats, when compared with control. These changes were almost similar to those noted in the HAM-implanted rats, except for the unaltered potassium and increased neutrophil levels. On Day 15, the total protein, A/G, lymphocyte, monocyte, and eosinophil levels remained unaltered in the PVA/NOCC-implanted rats, whereas urea, A/G, WBC, lymphocyte, and monocyte levels remained unchanged in the HAM-implanted rats. Histology and immunohistochemistry analyses revealed inflammatory infiltration in the PVA/NOCC-implanted rats, but not in the HAM-implanted rats. Although a low toxic tissue response was observed in the PVA/NOCC-implanted rats, further studies are necessary to justify the use of this material in tissue engineering applications.

Mini Open Carpal Tunnel Release Using Knifelight®: Evaluation of the Safety and Effectiveness of Using a Single Wrist Incision (Cadaveric Study)

This cadaveric study evaluates the margin of safety and technical efficacy of mini open carpal tunnel release performed using Knifelight® (Stryker Instruments) through a transverse 1 cm wrist incision. A single investigator released 32 wrists in 17 cadavers. The wrists were then explored to assess the completeness of release and damage to vital structures including the superficial palmar arch, palmar cutaneous branch and recurrent branch of the median nerve. All the releases were complete and no injury to the median nerve and other structures were observed. The mean distance of the recurrent motor branch to the ligamentous divisions was 5.7 ± 2.4 mm, superficial palmar arch was 8.7 ± 3.1 mm and palmar cutaneous branch to the ligamentous division was 7.2 ± 2.4 mm. The mean length of the transverse carpal ligament was 29.3 ± 3.7 mm. Guyon’s canal was preserved in all cases.