Purpose: The upward migration index (UMI) is a useful radiographic parameter for assessment of disorders of the rotator cuff. Utility of the UMI as a prognostic indicator for outcome following cuff repair has not been previously studied. The objective of this study was to determine if an association exists between the pre-operative UMI and the improvement in clinical and quality of life outcome scores following arthroscopic rotator cuff repair.

Method: Patients with a full thickness tear of the rotator cuff who underwent an arthroscopic repair of the cuff were selected for review. Eighty-four patients were included in the series. Mean patient age was 55 (range 25–78). The UMI was measured by MRI, and patients were divided into three groups: < 1.25 (GROUP A), 1.25–1.35 (GROUP B) and > 1.35 (GROUP C). Outcome variables were the non-weighted Constant-Murley score, ASES and the WORC assessed at baseline, 6 month and 12 months post-operatively. The paired t-test was used to carry out comparisons in follow up and one-way ANOVA was used to carry out comparisons between groups.

Results: There were 9 patients in group A, 33 in group B and 42 in group C. The improvement in scores from baseline to 1 year were as follows: ASES; 21.1 (A), 32.6 (B), and 38.4 (C); Constant 21.4 (A) 19.8 (B), and 24.2 (C) and WORC 31.9 (A), 42.7 (B), and 44 (C). Statistically significant improvements were observed in all groups in all outcome measures from baseline to 6 months and from 6 months to 1 year. Although the differences were not statistically significant (p> 0.05), a trend toward greater improvement in outcomes was observed with higher upward migration indices.

Conclusion: A lower UMI was associated with less improvement in functional and quality of life outcomes following arthroscopic rotator cuff repair, although these differences were not statistically significant. Patients with a low UMI demonstrated a significant improvement in functional and quality of life scores following surgery. In isolation, a low UMI should not represent a significant contraindication to treatment by arthroscopic rotator cuff repair.

Cementless femoral fixation is the gold standard in revision hip arthroplasty. Distal fixation is achieved using either a cobalt chrome or titanium stem. The purpose of this study is to report the long-term survivorship and clinical outcome of a titanium, long-stemmed, load-bearing calcar-replacement femoral component from an independent centre.

Eighty-one patients (average seventy-four years, range thirty-five to ninety-one) underwent hip arthroplasty with the Mallory-Head calcar-replacement femoral component, by a single surgeon. There were thirty-eight males and forty-three females with fifty-four hips initially revised for aseptic loosening, thirteen for peri-prosthetic fracture, and five for infection as a two-stage procedure. The implant was used as a primary device in eight patients with deformed proximal femurs. At most-recent follow-up, radiographic analysis was conducted and clinical outcome scoring was assessed using the SF-12, Harris Hip Score, and WOMAC questionnaire for surviving patients. Complications were also reviewed.

At a mean follow-up of 7.4 years (range four to fifteen), eight patients have died. There was one deep infection, three DVT’s, and two dislocations in the perioperative period. Six femoral stems have ultimately required another revision surgery for aseptic loosening, two for infection, and 1 for implant fracture at a mean of 5.6 years after initial revision. Four patients required removal of the proximal trochanteric bolt due to breakage or loosening. Overall survival of the implant at five years is 95% (CI 0.87–0.98) and 87% (CI 0.72–0.94) at ten years.

The clinical outcome of the Mallory-Head calcar-replacement femoral revision stem is reported from an independent centre. Although the results are encouraging, it would appear that proximal load-bearing fixation with the calcar-replacement stem is not as reliable as distal fixation. The use of a trochanteric bolt was associated with fracture of the greater trochanter or need for a separate surgical procedure for removal. For this series, there was an overall 11% failure rate at a mean follow-up of 7.4 years. The mechanical failure rate is 7.4%. Our overall and mechanical failure rates are somewhat higher than those of the implant developers, who reported 94% overall survival, and a 1.9% mechanical failure rate at a mean follow-up of eleven years.

Background: Greater tuberosity disuse osteoporosis is a consequence of rotator cuff tear. This is a significant problem as the tendon is implanted into a trough within the greater tuberosity during repair. Failure of the repair is a common complication (up to 50%). We hypothesise that failure in re-implantation is due to deficient bone cell response to mechanical stimulation in the tuberosity.

Methods: In order to establish whether these cells are capable of responding appropriately to mechanical stimuli, the response of bone cells derived from the tuberosity was compared with that of cells derived from the acromion. This was measured in terms of strain related increases in alkaline phosphatase (ALP) activity and nitric oxide (NO) production (which are recognised markers of osteoblast differentiation and their response to mechanical strain). Primary osteoblasts were cultured from samples of acromion and greater tuberosity taken during routine rotator cuff repair (n=10 pairs). The derived cells were:

Placed under cyclic strain at a physiological magnitude for 10 minutes at 1Hz using well established controls. Samples of media were analyzed for changes in NO and the cells were reacted for ALP activity, or:

Results: The results suggest that cells derived from the acromion exhibit significant strain related increases in cellular NO release and in ALP activity, whereas cells derived from the humeral greater tuberosity fail to exhibit any such increases. In marked contrast, cells derived from both sites exhibit increases in ALP activity in response to dexamethasone treatment.

Conclusions: Our results suggest that whilst cells derived from the tuberosity, after rotator cuff tear, respond appropriately to chemical and hormonal stimuli, they are compromised in their ability to respond to mechanical stimulation. Therefore, it is tempting to speculate that such relationships are also evident in vivo and that they underpin re-implantation failures.

Disuse osteoporosis of the greater tuberosity is a consequence of rotator cuff tear. This is a significant problem as the tendon is implanted into a trough within the greater tuberosity during repair. Failure of the repair is a common complication (up to 50%). We hypothesized that failure in re-implantation is due to deficient bone cell response to mechanical stimulation in the tuberosity. In order to establish whether these cells are capable of responding appropriately to mechanical stimuli, the response of bone cells derived from the tuberosity was compared with that of cells derived from the acromion. This was measured in terms of strain related increases in alkaline phosphatase (ALP) activity, nitric oxide (NO) and prostaglandin (PG) production (which are recognised markers of osteoblast differentiation and their response to mechanical strain).

Primary osteoblasts were cultured from samples of acromion and greater tuberosity taken during routine rotator cuff repair (n=5 pairs). The derived cells were placed under cyclic strain at a physiological magnitude for 10 min at 1Hz using well established controls. Samples of media were analysed for changes in NO and PG production and the cells were reacted for ALP. Cells were stimulated with dexamethasone, ascorbic acid and beta-glycerophosphate (established mediators of osteoblast differentiation) then reacted for ALP.

Preliminary results suggest that cells derived from the acromion exhibit significant increases in cellular NO release and in ALP activity, whereas cells derived from the humeral greater tuberosity fail to exhibit any such increases. In marked contrast cells derived from both sites exhibit increases in ALP activity in response to dexamethasone, ascorbic acid and beta-glycerophosphate treatment.

The results suggest that whilst cells derived from the tuberosity after rotator cuff tear respond appropriately to chemical and hormonal stimuli, they are compromised in their ability to respond to mechanical stimulation. It is tempting to speculate that such relationships are also evident in vivo and that they underpin reimplantation failures.