C. E. Ackroyd

Unicompartmental or total knee replacement?: FIVE-YEAR RESULTS OF A PROSPECTIVE, RANDOMISED TRIAL OF 102 OSTEOARTHRITIC KNEES WITH UNICOMPARTMENTAL ARTHRITIS

We randomised 102 knees suitable for a unicompartmental replacement to receive either a unicompartmental (UKR) or total knee replacement (TKR) after arthrotomy. Both groups were well matched with a predominance of females and a mean age of 69 years. Patients in the UKR group showed less perioperative morbidity, but regained knee movement more rapidly and were discharged from hospital sooner. At five years, two UKRs and one TKR had been revised; another TKR was radiologically loose. All other knees appeared to be clinically and radiologically sound. Pain relief was good in both groups but the number of knees able to flex > or =120 degrees was significantly higher in the UKR group (p < 0.001) and there were more excellent results in this group. Our findings have shown that UKR gives better results than TKR and that this superiority is maintained for at least five years.

The Avon patellofemoral arthroplasty: FIVE-YEAR SURVIVORSHIP AND FUNCTIONAL RESULTS

We report the mid-term results of a new patellofemoral arthroplasty for established isolated patellofemoral arthritis. We have reviewed the experience of 109 consecutive patellofemoral resurfacing arthroplasties in 85 patients who were followed up for at least five years. The five-year survival rate, with revision as the endpoint, was 95.8% (95% confidence interval 91.8% to 99.8%). There were no cases of loosening of the prosthesis. At five years the median Bristol pain score improved from 15 of 40 points (interquartile range 5 to 20) pre-operatively, to 35 (interquartile range 20 to 40), the median Melbourne score from 10 of 30 points (interquartile range 6 to 15) to 25 (interquartile range 20 to 29), and the median Oxford score from 18 of 48 points (interquartile range 13 to 24) to 39 (interquartile range 24 to 45). Successful results, judged on a Bristol pain score of at least 20 at five years, occurred in 80% (66) of knees. The main complication was radiological progression of arthritis, which occurred in 25 patients (28%) and emphasises the importance of the careful selection of patients. These results give increased confidence in the use of patellofemoral arthroplasty.

The Lubinus patellofemoral arthroplasty: A FIVE- TO TEN-YEAR PROSPECTIVE STUDY

We present a prospective review of the outcome of 76 Lubinus patellofemoral arthroplasties carried out in 59 patients between 1989 and 1995. At a mean follow-up of 7.5 years, 62 knees in the 48 patients were reviewed; 11 patients (14 knees) had died. None was lost to follow-up. The clinical outcome using the Bristol Knee Scoring system was satisfactory in 45% of the cases. Maltracking of the patella, resulting in lateral tilt, subluxation and polyethylene wear, was the most common complication (32%). Revision surgery was carried out in 21 knees (28%) giving a cumulative survival rate of 65% (confidence interval (CI) 49 to 77) at eight years. The survival rate for revision and moderate pain was 48% (CI 36 to 59) at six years. Progression of arthritis was seen in seven cases (9%). In five of these (6.5%), the symptoms were severe enough to need revision surgery. Due to the high proportion of unsatisfactory results, we have discontinued the use of this prosthesis.

Lateral unicompartmental knee replacement: SURVIVORSHIP AND CLINICAL EXPERIENCE OVER 21 YEARS

We describe 88 knees (79 patients) with lateral unicompartmental osteoarthritis which had been treated by the St Georg Sled prosthesis. At a mean follow-up of nine years (2 to 21) 15 knees had revision surgery, nine for progression of arthritis, six for loosening, four for breakage of a component and four for more than one reason. Six patients complained of moderate or severe pain at the final follow-up. Only five knees were lost to follow-up in the 21-year period. We performed survivorship analysis on the group using revision for any cause as the endpoint. At ten years the cumulative survival rate was 83%, and at 15 years, when ten knees were still at risk, it was 74%. Based on our clinical results and survival rate the St Georg Sled may be considered to be a suitable unicompartmental replacement for isolated lateral compartment osteoarthritis.

Development and early results of a new patellofemoral arthroplasty

A new patellofemoral arthroplasty is described, based on a previous design of total knee arthroplasty. The indications are for patients with specific isolated patellofemoral disease with advanced chondral or arthritic damage. The design and technique of insertion is detailed. Three hundred six patellofemoral arthroplasties have been done in 240 patients. The initial results show a high level of pain relief and improvement in function. Two-year followup is available for treatment of 124 knees and 5-year followup is available for treatment of 33 knees. There has been no deterioration in pain or function with followup to 5 years, and there were no late complications attributable to the arthroplasty. Disease progression in the tibiofemoral joint has occurred in 14 patients (16 knees, 5%) requiring revision in 10 of these patients (11 knees, 3.6%). Persistent anterior knee pain was recorded in 14 knees (4%). The short-term results using this new design were better than those of the prosthesis that we used previously, especially concerning malalignment and wear. It offers a reasonable alternative to total knee replacement in the small group of patients with isolated patellofemoral disease. Level of Evidence: Therapeutic study, Level II (prospective cohort study). See the Guidelines for Authors for a complete description of levels of evidence.

The length of the patellar tendon after unicompartmental and total knee replacement

Patella infera may occur after reconstruction of the anterior cruciate ligament (ACL), high tibial osteotomy and total knee replacement (TKR). Restriction of movement of the knee and pain may result. Our aim was to compare the incidence and to assess the effects of patella infera after TKR and unicompartmental knee replacement (UKR). We reviewed radiographs of the knees of 84 patients who had had either TKR or UKR as part of a randomised, controlled trial. The length of the patellar tendon was measured on serial radiographs taken before, at eight months and at five years after operation. There was no significant change in the length of the patellar tendon after UKR, but a significant reduction was observed after TKR. Five years after the operation, the shortening of the tendon had increased to a mean of 3.5 mm. Of the knees with TKR reviewed at five years, 34% developed patella infera, defined as 10% or more of shortening, compared with 5% of those with UKR. Shortening was greatest in those knees which had required a lateral release; in this subgroup the mean shortening was 7.2 mm. Shortening correlated with restriction of movement and pain in the knee. Our study has shown that patella infera develops in most patients after TKR with lateral release, and in approximately 25% of patients after TKR without this additional procedure. Patella infera rarely occurs after UKR. It is associated with restriction of movement and pain in the knee. It may be an effect of the more extensive exposure required to perform TKR and may, in part, explain the better clinical results of UKR.

Removal of forearm plates. A review of the complications

We studied 55 patients who had undergone elective removal of forearm plates between 1980 and 1986; 44 plates were removed from the radius and 37 from the ulna. Before removal only 20 patients (36%) had definite symptoms attributable to the plates, but 44 patients (80%) were advised by the surgeon to have the plates removed. In 22 cases (40%) the operation was followed by a significant complication. The complication rate was higher with junior surgeons and was permanent in 50% of cases. It is recommended that forearm plates should be removed only if they are causing significant symptoms, and that the operation should not be delegated to the most junior surgeon.

Survivorship of the St Georg Sled medial unicompartmental knee replacement beyond ten years.

There have been several reports of good survivorship and excellent function at ten years with fixed-bearing unicompartmental knee replacement. However, little is known about survival beyond ten years. From the Bristol database of over 4000 knee replacements, we identified 203 St Georg Sled unicompartmental knee replacements (174 patients) which had already survived ten years. The mean age of the patients at surgery was 67.1 years (35.7 to 85) with 67 (38.5%) being under 65 years at the time of surgery. They were reviewed at a mean of 14.8 years (10 to 29.4) from surgery to determine survivorship and function. There were 99 knees followed up for 15 years, 21 for 20 years and four for 25 years. The remainder failed, were withdrawn, or the patient had died. In 58 patients (69 knees) the implant was in situ at the time of death. Revision was undertaken in 16 knees (7.9%) at a mean of 13 years (10.2 to 21.6) after operation. In seven knees (3.4%) this was for progression of arthritis, in three (1.5%) for wear of polyethylene, in four (2%) for tibial loosening, in two (1%) for fracture of the femoral component and in two (1%) for infection. Two knees (1%) were revised for more than one reason. The mean Bristol knee score of the surviving knees fell from 86 (34 to 100) to 79 (42 to 100) during the second decade. Survivorship to 20 years was 85.9% (95% CI 82.9% to 88.9%) and at 25 years was 80% (95% CI 70.2% to 89.8%). Satisfactory survival of a fixed-bearing unicompartmental knee replacement can be achieved into the second decade and beyond.

St. Georg sledge for medial compartment knee replacement: 461 arthroplasties followed for 4 (1-17) years

We evaluated the long-term outcome of 461 medial compartment knee arthroplasties operated at one orthopedic center from 1974 to 1993 through survivorship analysis. Prospective assessment was based on clinical examinations using a modified Bristol knee-scoring system and complete radiographical knee survey. 92% had good or excellent results on objective scoring, and range of motion averaged 112 degrees. 3 criteria were applied to indicate failure: 1) revision or recommended revision, 2) severe-to-moderate pain or revision, 3) lost to follow-up. 20 arthroplasties were revised or recommended to be revised at mean 5.5 years. The incidence of failure due to progression of arthrosis in the unreplaced compartment was low (< 2%). Loosening or wear occurred in 6 cases (1.5%), 2 of which developed fracture of implant. With revisions only as end-point to failure, the survival was 87% at 10 years (95% CI 81%-93%, effective number at risk = 133). In addition to revisions, 19 knees were considered to have failed, as moderate-to-severe pain was noted at follow-up and the survival was reduced to 74% at 10 years with pain or revision as endpoint (95% CI 65%-82%, effective number at risk = 105). We conclude that unicompartmental knee arthroplasty gives long-term pain relief in elderly patients with medial compartment arthrosis.

The fixation and prognosis of trochanteric fractures. A randomized prospective controlled trial.

A randomized prospective controlled trial of 155 patients with trochanteric fractures compared the AO dynamic hip screw and the Jewett nail plate. The dynamic hip screw showed significantly less evidence of mechanical failure and a lower incidence of reoperation. The implant had no effect on mortality or success of rehabilitation. Mortality was significantly associated with social dependence before fracture and the hospital attended. Capacity to return home and walk again were associated with mobility before fracture and age. While the fate of the majority of patients appeared to be determined by their state before fracture, hospital differences appear to offer the greatest potential for influencing the outcome of this condition.