When do total knee replacements fail?

BACKGROUND: A recent study has provided evidence-based guidelines for the follow-up of cemented total hip arthroplasty. As yet, there are no such guidelines on the surveillance of total knee arthroplasty. We reviewed the outcomes of patients who underwent this procedure in 1998 and 1999 at our institution. METHODS: All patients were identified from operating theater log books. The follow-up data was then retrieved from the electronic patient record system used at our institution. We recorded the age, sex, side of procedure, evidence of radiological loosening, and date of revision surgery. The data with regards to radiological evidence of loosening and revision surgery were then analyzed using a R statistical software package. From this we were able to plot Kaplan-Meier survival and hazard plots. RESULTS: We identified 296 primary total knee arthroplasties. Using radiological evidence of loosening as the end point, we found that there was a gradual increase in failure with a peak at 8 years (Fig. 1). There was a 10-year survival rate of 85.8%. Using revision surgery, for any cause, as the end point, we found that again there was a constant rate increase up to a peak at 8 years (Figs. 2 and 3). There was a 10-year survival rate of 91.5%. CONCLUSIONS: Once the patient has made it through the first postoperative year, they do not need to be followed up again until 8 years, assuming they remain asymptomatic. LEVEL OF EVIDENCE: Therapeutic Level IV.

Preliminary results of an uncemented trabecular metal tibial component in total knee arthroplasty.

Trabecular metal has several theoretical advantages for the long-term survival of a tibial component. We report the results of a prospective cohort of 105 consecutive primary total knee arthroplasties using an uncemented trabecular metal (tantalum) tibial component at a minimum 3-year follow-up (range, 36-56 months). There was a significant improvement in Oxford Knee scores and Short Form-12 scores postoperatively. There was no radiolucency at the implant-bone interface on any postoperative radiograph. There has been one (1%) revision of the tibial component for trauma. The 3-year results using this prosthesis are as good as those published for the commonly used cemented prostheses. Longer follow-up is required to see whether these results are maintained over time.

Do we need to follow up primary total hip replacements?

No evidence based guidelines on surveillance of cemented total hip arthroplasty exist. We reviewed outcomes of this procedure from 1996 & 1997. Patients were identifed from theatre log books. Follow up data was retrieved from patient records. Evidence of radiological loosening & time of revision were recorded. Data was analysed using a ® statistical software package. We identified 425 primary total hip arthroplasties. Using radiological evidence of loosening as the end point we found an initial peak and another at 8 years. 10 year survival rate was 86%. Using revision surgery as the end point we found an initial peak & another at 8 years. 10 year survival rate was 92%. Once the patient has made it to 1 year, no follow up is required until 8 years; unless symptomatic.

The behaviour of knots and sutures during the first 12 hours following a Bankart repair.

It has been reported that the effectiveness of arthroscopic procedures in terms of preventing recurrent dislocation has not matched that from open techniques. Also little is known about how these knots behave when exposed to physiological loading following repair. This study presents the development of a practical tool to allow surgeons to test the quality of their arthroscopic knots and allow them to make choices with regard to knot configuration and suture material. This study uses an apparatus to model the repair of a Bankart lesion. Ten examples of the Duncan loop and SMC knots were tied using PDS, Ethibond, Panacryl and Fibrewire. An arthroscopic knotting technique was used. Reverse slippage occurring during the tying process was recorded. Each knot was then left for 12 hours under loads equivalent to a Bankart repair and the subsequent reverse slippage was recorded. After initial passing of the Duncan loop and after passing of locking hitches the sutures were ranked inversely to size of suture loop (resistance to slippage). Only Fibrewire showed a significant difference (5.7 +/- 1.03 mm to 5.66 +/- 0.5 mm; p <0.05). After 12 hrs, some evidence of reverse slippage was noted, especially with Fibrewire (5.66 +/- 0.5 mm--significant p <0.05). The SMC knot showed generally inferior results. In this study using arthroscopic techniques, Fibrewire performed less well than other materials.

Correlation between the length from the elbow to the distal interphalangeal joint of the little finger and the length of the intramedullary nail selected for femoral fracture fixation.

AIM: To determine whether there is a correlation between the length of forearm to the distal interphalangeal joint (DIPJ) of the little finger and length of antegrade intramedullary (IM) femoral nails in adults. STUDY DESIGN AND METHODS: Measurements from the tip of the olecranon to the DIPJ of the ipsilateral upper limb was taken in 30 patients undergoing antegrade IM femoral nails. The length of the IM nails inserted was determined by intra-operative measurements using a guide wire. The two measurements were analysed for correlation and mean difference. RESULTS: The mean forearm to DIP of little finger length was 38.86 with a standard deviation of 2.83. The mean IM length and standard deviation were 38.56 and 2.77 respectively. The difference between the two means 0.3 (95% CI). Correlation testing between the two variables shows a positive relationship (Pearson Correlation factor of 1). The scatter plot shows a positive linear relationship. CONCLUSIONS: Length of the forearm from the tip of the olecranon to the DIP joint of the little finger represents the ideal length of IM nail for the femur. It can be readily performed with the use of a tape measure and can serve as a useful adjunct to determining ideal length in cases where the contralateral femur cannot be used.

Functional Outcome and Complications at 2.5 Years Following Volar Locking Plate Fixation of Distal Radius Fractures.

Distal radius fractures are increasingly treated by internal fixation, but there have been relatively few studies relating to functional outcome at 12 months or more. The aim of this study was to ascertain the patient reported function of the wrist at a minimum of 12 months following fixation of a distal radius fracture, the time taken to return to work, and the complication rate. We conducted a retrospective review of 187 consecutive patients treated by a specialist hand and wrist trauma team at a tertiary referral unit over a 5 year period. Mean age was 57.3 years (range 16-93). Median time to surgery was 4 days (interquartile range 2-9). Median follow up was 31 months (interquartile range 23-41 months). The median PRWE score was 3; (range 0-83). There was no difference in outcome in patients who had surgery delayed by greater than 2 weeks (p > 0.05). The median time to return to work was 5 weeks (interquartile range 1-8 weeks). There were 15 complications (8 %) including 3 tendon injuries. We have demonstrated an early return to work in patients who were employed, a low complication rate, and highly favourable functional outcomes at a mean of 30 months postoperatively. We recommend the use of the DVR plate and involvement of a dedicated hand and wrist trauma team for treatment of unstable fractures of the distal radius.