We carried out 60 revision procedures for failed porous coated anatomic total knee replacements in 54 patients, which were divided into two groups. The 14 knees in group I had a well-fixed femoral component at surgery which was retained, and in the 46 knees in group II both tibial and femoral components were loose and were revised using a variety of implants. Our review comprised clinical and radiological assessment.

A total of 13 knees required a second revision. Six (42%) in group I failed very early (mean 2.1 years) when compared with seven (15%) in group II (mean 6.8 years). Failure was due to wear of the polyethylene insert by the abraded, retained femoral component (crude odds ratio 4.07; 95% CI 1.07 to 15.5). We recommend a complete change of primary bearing surfaces at the time of revision of an uncemented total knee replacement in order to prevent early wear of polyethylene.

There is little data on the long-term outcome of rotating hinge total knee arthroplasty. We provide a clinical and radiographic assessment of survivorship of the Kinematic rotating hinge total knee arthroplasty (How-medica, Rutherford, NJ), in a series of 72 implants, performed by a single surgeon in one unit, between 1983 and 1997. Survival analysis using known all cause revision revealed a 92% five-year implant survival, but worst-case scenario was 31% at five years.

In a subset of 27 patients we used the Nottingham Health Profile (NHP) to assess prospectively the changes in health-related quality of life following rotating hinge arthroplasty. In this salvage arthroplasty setting we demonstrate a significant improvement in two modalities of the NHP (pain and physical mobility).

Purpose: To study the functional outcome and survivorship of custom designed knee implants for revision and primary total knee replacement surgery where off-the-shelf prosthesis were unsuitable.

Methods: We prospectively reviewed the clinical and radiological results of 20 patients with 23 custom designed total knee prosthesis from 1991 to 2000. The indications were bone loss due to multiple revisions of total knee prosthesis and debridement for infection; peri-prosthetic fractures; bone deformity with rickets and small bones of patients with juvenile chronic arthritis. All the patients had their knee designed and manufactured in the Centre for Biomedical Engineering, University College London Medical School, Stanmore, UK. There were 4 different designs of knee prosthesis used: Condylar knee of miniature size, CAD-CAM knee, Superstabiliser and Rotating Hinges. Patients were operated upon by one senior surgeon and the Hospital for Special Surgery score taken pre-operatively, at three months, and yearly by an independent research physiotherapist.

Results: Clinical and radiological results after an average of 62.5 months (range 22 to 118 months) showed that the average Hospital for Special Surgery Score improved significantly (p=0.025) from 13.5 points (range 0–48) pre-operatively to 86.5 points (range 62–96 points). Average maximum flexion post operatively measured 86.4 degrees (range 60–122 degrees). 16 knees had excellent, 5 good and 2 poor results. Three patients had an extension lag ranging from 15–25 degrees. Only one patient with juvenile chronic arthritis needed revision at five years after the index arthroplasty.

Conclusion: The clinical and radiological results compare favorably with those who had standard knee prosthesis with similar indications. Our results support the use of a custom designed knee implant as a salvage prosthesis and an alternative to arthrodesis or amputation.

Purpose: To study the effect of retaining an abraded femoral component on the outcome of primary revision of uncemented total knee prosthesis.

Method: 66 revision procedures for failed uncemented porous coated anatomic (PCA) total knee replacement were performed in 60 patients. At review, four patients had died while two were lost to follow up, therefore 60 knees in 54 patients were included in this prospective study. The principal indications for primary revision were polyethylene wear and loosening of the tibial base plate. 14 patients had a well fixed femoral component and hence were retained while 46 patients had both the components revised. All patients were prospectively assessed prior to surgery, at three months, six months and yearly thereafter. Review comprised clinical and radiological assessment. The mean follow up was 8.4 yrs (7–12 yrs)

Summary of results: The mean pre-operative Hospital for Special Surgery knee score after the first revision improved at a follow up of 8.4yr (7–12yr) giving 39 (65%) excellent, 17 (28.4%) good and four (6.6%) poor results. 13 out of 60 knees needed a further revision. Six of these second revisions which had only the tibial component changed failed very early (mean of 2.1 yr) when compared to the rest (6.8yr), probably due to wear between the abraded retained femoral component and polyethylene insert. The estimated odds ratio (relative risk) of second revision in patients with retained femoral component compared to those with revision of both the components was 4.17 (95% C.I. 1.07 – 15.4).

Conclusion: We recommend exchange of all the components at the time of revision of PCA knee prostheses. Significance: To our knowledge, this is the only study involving such a large number of PCA revisions and looking into the effect of retaining the femoral component compared to changing both the components on the outcome of revision.

Aim: To prospectively determine the functional outcome of revision total knee replacement (TKR).

Method: We carried out a prospective outcome study recruiting 65 consecutive revision total knee replacements carried out by the senior author between 1992 and 1995. The indications for revision were aseptic loosening in 40 cases, instability in 7, infection in 4, and 16 cases for other causes. All patient was assessed preoperatively and at 3 and 12 months postop using the Nottingham Health Profile (NHP) to measure general health status. As part of this ongoing study, followup data is available for 24 patient at 5 years.

Results: There were 65 revisions in 60 patients, 5 being bilateral. There were 37 females and 23 males, with a mean age of 63 years (range 29 to 86 years). The preoperative scores showed that the patient had significant disability related to their failed TKR. Three months postop, there was a significant improvement in the NHP scores for pain and social isolation. At 12 months, the level of pain was again significantly improved over the 3 month score.

At 5 years, the pain score for the revision group deteriorated but remained better than the baseline level. This is in contrast to post primary TKR, where the improvement in pain score was maintained from 3 months onwards.

Conclusion: This study shows a significant improvement in the level of pain following revision knee arthroplasty. However, patients remain significantly disabled afterwards and do not show the very marked improvement in general health seen after primary TKR.

Aim: To determine the quality of life and radiological outcome of the rotating hinge total knee prosthesis as a salvage procedure for failed knee arthroplasty.

Methods: Forty-seven consecutive revision total knee arthroplasties, using the rotating hinge component, implanted between November 1983 and June 1997, were studied. The principal indications for surgery were pain with ligamentous laxity and gross bone loss. There were 43 patients, 11 males, 32 females, 19 left and 28 right, 21 with rheumatoid disease and 22 with osteoarthritis. The mean age at revision was 68 years, mean time from primary procedure to revision of 8 years and a mean number of previous knee procedures of 1.6 (range 1–5). The average time to final follow-up was 5 years. Quality of life was determined using the Nottingham Health Profile (NHP) combined with standard clinical and radiological assessment.

Results: Of the 47 revision procedures, full clinical follow-up information was available on 43 (91.5%), radiographic follow-up on 38 (80.9%). Complications occurred in 10 out of the 47 arthroplasties (21.3%) including 4 deep infections, 2 femoral fractures, 2 patients with clinically apparent aseptic loosening and 2 significant extensor mechanism problems. Survivorship analysis revealed a 5year cumulative implant survival of 89%. Significant improvements in quality of life (pain and physical mobility) were shown at 12 months post-operatively.

Discussion: This is a prospectively-studied series of salvage arthroplasty procedures. We regard quality of life as a key indicator of surgical success after knee arthroplasty. Rotating hinge arthroplasty offers objective and reproducible improvement in quality of life for failed knee arthroplasty with ligamentous instability.

Between 1992 and 1994 we performed a prospective study of the effect of total knee replacement (TKR) on the health status of 119 patients over the age of 80 years who had had a primary unilateral TKR.

The Nottingham Health Profile was used to assess this before and at three and 12 months after operation. We found a significant improvement in the scores for pain, emotional reaction, sleep and physical mobility at three months. After 12 months, the scores for pain and sleep were well maintained. The other factors had deteriorated slightly but remained better than before operation.

Our findings show that TKR leads to a significant improvement in the general health status of the very elderly.

We performed an independent survivorship analysis on 208 Kinematic Condylar knee replacements with a minimum follow-up of ten years and a mean of 12 years. Seven patients had been lost to follow-up. At ten years the estimated survival was 92% (95% confidence limits 95% and 87%) and when stratified for diagnosis and thickness of polyethylene there was no statistical difference (p > 0.05) in survivorship of knees with osteoarthritis or rheumatoid arthritis.

We conclude that the original design of the Kinematic Condylar knee replacement has a good record and that adequate evaluation of new designs of implant should be undertaken before they are widely introduced.

The Kinematic Stabilizer is a posterior-cruciate-substituting design of total knee replacement. We have reviewed 109 primary total knee replacements in 95 patients at a mean follow-up time of 12.7 years (10 to 14). We used survival analysis with failure defined as revision of the implant. This gave a cumulative survival rate of 95% (95% CI± 5%) at ten years and 87% (± 10%) at 13 years.

These results from an independent centre confirm the value of an established design of cemented total knee replacement and question the wisdom of the introduction of modifications and new designs without properly controlled trials.

We measured the levels of cobalt and chromium in the serum in three groups of patients after uncemented porous-coated arthroplasty. Group 1 consisted of 14 consecutive patients undergoing revision for aseptic loosening. Group 2 comprised 14 matched patients in whom the arthroplasty was stable and group 3 was 14 similarly matched patients with arthritis awaiting hip replacement. Specimens were analysed using atomic absorption spectrophotometry.

Aseptic loosening of a component resulted in a significant elevation of serum cobalt (p < 0.05), but not of serum chromium. The relative risk of a component being loose, if the patient had a serum cobalt greater than 9.0 nmol/l, was 2.8.

1. Anterior synovectomy was undertaken in sixteen knees of fourteen patients with rheumatoid arthritis associated with popliteal or calf cysts. Subsequent changes in the knees and cysts were observed clinically and by arthrography.

2. In all instances there was alleviation of symptoms and in fourteen cases the cysts disappeared.

3. It is suggested that anterior synovectomy is the logical treatment of a posterior cyst associated with rheumatoid arthritis of the knee.