Rotator cuff tears are common injuries which often require surgical repair. Unfortunately, repairs often fail [1] and improved repair strength is essential. P2 Porous titanium (DJO Surgical, Austin TX) has been shown to promote osseointegration [2,3] and subdermal integration [4]. However, the ability of P2Porous titanium to aid in supraspinatus tendon-to-bone repair has not been evaluated. Therefore, the purpose of this study was to investigate P2 implants used to augment supraspinatus tendon-to-bone repair in a rat model [5]. We hypothesized that supraspinatus tendon-to-bone repairs with P2 implants would allow for ingrowth and increased repair strength when compared to standard repair alone. Thirty-four adult male Sprague-Dawley rats were used (IACUC approved). Rats received bilateral supraspinatus detachment and repair with one limb receiving P2 implant. Animals were sacrificed at time 0 (n=3), 2 weeks (n=8), 4 weeks (n=9) and 12 weeks (n=14). Limbs were either dissected for histological and SEM analysis or mechanical testing as described previously [5]. Specimens for histology and SEM were embedded in PMMA for tissue-implant interface analysis. Specimens were first viewed in SEM under BSE to detect bony ingrowth, then stained with Sanderson's Rapid Bone Stain and viewed under transmitted and polarized light for tissue ingrowth. Comparisons were made using Student's t-tests with significance at p≤0.05.INTRODUCTION
METHODS
We aimed to assess whether using long stem femoral components, with cemented distal fixation and proximal impaction grafting allows early patient mobilisation, reconstitution of the proximal femur and long term stability of fixation in patients with aseptic loosening and proximal femoral analysis. Over the past ten years 239 patients have been treated with an Elite Plus cemented long stem femoral implant, 33% with concomitant proximal impaction bone grafting. Many of the patients had co-morbidities. The average age at revision was 72 years (range 48 to 91). There was a slight female predominance. Fourteen percent of hips had been previously revised. Forty-eight patients were deceased and 22 were not available for follow-up; this left a cohort of 169 patients who were available for radiological and questionnaire review at an average of 4.5 years. According to the Paprosky grading for pre-operative bone loss 40% had moderate to severe bone loss (grade IIIb or IV). The Barrack grading was used to assess the cement mantle post-operatively with 65% showing good cementation. The Harris and O'Neill grades were used at final review to assess probability of loosening with only 8% being probably or definitely loose. The average Oxford Hip Score was 29. Mesh ± cables were required in a third of cases to allow adequate containment and pressurisation. It was generally felt that the long stem needed to be at least one third longer than the initial component. The re-revision rate was 1.2 with a 10 year survivorship analysis of 94%. The complication rate of almost 6% included periprosthetic fractures, dislocations, infection and mesh breakage. A long stem cemented femoral implant can be useful in bypassing proximal femoral deficiency in the appropriate patient.
