The Avon patellofemoral joint arthroplasty: two- to 18-year results of a large single-centre cohort.

Aims: This study reports on the medium- to long-term implant survivorship and patient-reported outcomes for the Avon patellofemoral joint (PFJ) arthroplasty. Patients and Methods: A total of 558 Avon PFJ arthroplasties in 431 patients, with minimum two-year follow-up, were identified from a prospective database. Patient-reported outcomes and implant survivorship were analyzed, with follow-up of up to 18 years. Results: Outcomes were recorded for 483 implants (368 patients), representing an 86% follow-up rate. The median postoperative Oxford Knee Score (0 to 48 scale) was 35 (interquartile range (IQR) 25.5 to 43) and the median Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, 0 to 100 scale) was 35 (IQR 25 to 53) at two years. There were 105 revisions, 61 (58%) for progression of osteoarthritis. All documented revisions were to primary knee systems without augmentation. The implant survival rate was 77.3% (95% confidence interval (CI) 72.4 to 81.7, number at risk 204) at ten years and 67.4% (95% CI 72.4 to 81.7 number at risk 45) at 15 years. Regression analysis of explanatory data variable showed that cases performed in the last nine years had improved survival compared with the first nine years of the cohort, but the individual operating surgeon had the strongest effect on survivorship. Conclusion: Satisfactory long-term results can be obtained with the Avon PFJ arthroplasty, with maintenance of patient-reported outcome measures (PROMs), satisfactory survival, and low rates of loosening and wear. Cite this article: Bone Joint J 2018;100-B:1162-7.

Long-term (ten- to 15-year) outcome of arthroscopically assisted Elmslie-Trillat tibial tubercle osteotomy.

We present the ten- to 15-year follow-up of 31 patients (34 knees), who underwent an Elmslie-Trillat tibial tubercle osteotomy for chronic, severe patellar instability, unresponsive to non-operative treatment. The mean age of the patients at the time of surgery was 31 years (18 to 46) and they were reviewed post-operatively, at four years (2 to 8) and then at 12 years (10 to 15). All patients had pre-operative knee radiographs and Cox and Insall knee scores. Superolateral portal arthroscopy was performed per-operatively to document chondral damage and after the osteotomy to assess the stability of the patellofemoral joint. A total of 28 knees (82%) had a varying degree of damage to the articular surface. At final follow-up 25 patients (28 knees) were available for review and underwent clinical examination, radiographs of the knee, and Cox and Insall scoring. Six patients who had no arthroscopic chondral abnormality showed no or only early signs of osteoarthritis on final radiographs; while 12 patients with lower grade chondral damage (grade 1 to 2) showed early to moderate signs of osteoarthritis and six out of ten knees with higher grade chondral damage (grade 3 to 4) showed marked evidence of osteoarthritis; four of these had undergone a knee replacement. In the 22 patients (24 knees) with complete follow-up, 19 knees (79.2%) were reported to have a good or excellent outcome at four years, while 15 knees (62.5%) were reported to have the same at long-term follow-up. The functional and radiological results show that the extent of pre-operatively sustained chondral damage is directly related to the subsequent development of patellofemoral osteoarthritis.

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.

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.

Arthritis progression after patellofemoral joint replacement.

Progressive symptomatic tibiofemoral osteoarthritis (OA) following patellofemoral joint replacement (PFJR) may necessitate revision to total knee arthroplasty. This study was designed to quantify this problem in a prospective series of 103 consecutive patients who underwent PFJRs undertaken at our institution. At a mean follow-up of 7.1 years (66-102 months), 14 knees (14%) have been revised, 12 of those (12%) because of the development of symptomatic tibiofemoral OA, with a mean time to revision of 55 months (range 14 to 95 months). Available radiographs of the 89 unrevised knees were subject to blinded and randomised assessment by two observers. Postoperative AP knee radiographs were scored to assess for tibiofemoral OA progression, with definite progression seen in a median of 7% of medial compartments but 0% of lateral compartments, over a mean period of 51 months. Sulcus angles on preoperative 30 degrees skyline radiographs were measured to assess for trochlear dysplasia. Seventeen percent of the knees without preoperative trochlear dysplasia have been revised for progression of tibiofemoral OA, compared to none of the knees with preoperative trochlear dysplasia. Furthermore, in the unrevised knees, statistically significantly more radiographic progression of tibiofemoral OA was seen in those without preoperative trochlear dysplasia (p = 0.01). Our results suggest that progressive tibiofemoral OA following PFJR is an important cause of failure, but it is seen significantly less frequently when the patellofemoral arthritis is secondary to dysplasia of the femoral trochlea, suggesting that these patients are the ideal candidates for PFJR.

Fixed or mobile bearing unicompartmental knee replacement? A comparative cohort study.

Unicompartmental knee replacement (UKR) for anteromedial osteoarthritis is a well-established technique. Numerous clinical outcome studies demonstrate good medium and long-term results. The aim of this prospective study was to compare the complications and short-term clinical outcome of the St. Georg Sled, a fixed bearing UKR, with the Oxford mobile bearing UKR. Outcome at 2 years was assessed using the Bristol knee score and the Oxford knee score; in addition, complications occurring since formal scoring at 2-year follow-up were recorded. A total of 47 Oxford UKRs and 57 St. Georg Sled UKRs were performed in 91 patients, none of whom were lost to follow-up. At 2 years, both outcome measures were better for the St. Georg Sled Group. The pain component of the Bristol knee score was significantly better for this group (p-value = 0.013). Three patients in the Oxford group had bearing dislocations and a further four patients required revision (mean time to revision 3.0 years). In the St. Georg Sled group, three patients required revisions (mean time to revision 3.4 years). These results demonstrate that in the short-term, the Oxford mobile bearing prosthesis has a higher re-operation rate and that the St. Georg Sled achieves better pain relief. The functional scores of the two groups were similar.

Medial compartment arthroplasty of the knee.

Compartmental arthritis forms a significant subgroup of patients presenting with osteoarthritis of the knee. Involvement of the medial compartment is the most common and can be successfully treated by unicompartmetal arthroplasty. The first step is to obtain an accurate diagnosis of the process of the disease, and, particularly, to evaluate the integrity of the ACL. Assessment requires clinical, radiographic and perhaps arthroscopic evaluation, but the final decision will depend upon judgement taken at the time of the arthrotomy. This improves with experience and it is essential that the surgeon has sufficient basic understanding and regular practice. The decision on the design of the prosthesis is critical. This should be based on ten-year survivorship studies with a success rate of at least 85% to 90%. The technically more demanding prostheses can give excellent long-term results in some centres. The less complex prostheses can produce good long-term results in more general use. Most studies consistently report lower complication rates, more rapid recovery and long-term results of better quality than TKR. Set against this must be the recognition that failure because of progression of the disease can occur in addition to that due to mechanical causes. There is no convincing evidence that the well-tried and tested prostheses have a significantly greater overall rate of failure than TKR. Reports of revision show that this is not technically demanding and is considerably simpler than for failed TKR with results which are probably little different from those of a primary arthroplasty. The resurgent interest in compartmental arthroplasty is based on encouraging reports from those few centres which have pioneered the treatment. Successful results require a detailed knowledge of the pathology, indications, technique and management of the procedure. This philosophy adds several extra dimensions to the routine of established knee arthroplasty.

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.

A comparative study of the medial St Georg sled and kinematic total knee arthroplasties. Ten-year survivorship.

We have studied the long-term outcome of 408 primary medial St Georg Sled unicompartmental arthroplasties of the knee and 531 primary Kinematic total knee arthroplasties using survivorship analysis. The operations were performed by a number of surgeons under the supervision of two consultants at one orthopaedic centre. Prospective clinical assessment was carried out before and at 2, 5, 8, 10, 12 and 15 years after operation. Failure was defined as follows: revision or removal of the implant; the presence of moderate or severe pain; or 'worst-case' with all patients lost to follow-up. Cumulative survival rates at ten years were calculated using life tables. The follow-up rate was 97%. At ten years, 25 medial sled arthroplasties and 20 Kinematic knee arthroplasties had been revised. With revision or removal as the survivorship endpoint at ten years there was a success rate of 87.5% for the medial sled and 89.6% for the Kinematic knee arthroplasty. When moderate or severe pain was included these rates became 79.4% for both arthroplasties. There was no statistically significant (p > 0.05) difference between the rates of survival for the two arthroplasties using either of the endpoint criteria. Good or excellent results were recorded for 77.9% of the medial sled knees and 75.1% for the Kinematic knees. The former had 93.8% of cases with a final range of movement in excess of 90 degrees compared with 83.7% for the Kinematic knees (p < 0.01). We conclude that at a single orthopaedic centre in the UK, the St Georg Sled medial compartment arthroplasty for appropriate specific indications offers predictable survivorship at ten years which is comparable with that of the Kinematic total knee 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.

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.

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.

Day-case or short-stay admission for arthroscopic knee surgery: a randomised controlled trial.

The Royal Colleges, The Audit Commission, and politicians have encouraged day-case care for patients undergoing arthroscopic knee surgery. However, there remains both public and professional concern regarding the acceptability and safety of this form of management, although there are clear economic benefits. In a prospective randomised controlled trial, 50 patients underwent arthroscopic surgery as a day-case and 50 patients were admitted overnight. Outcome was assessed by postal questionnaire 4 weeks after discharge. A linear visual analogue scale was used to measure pain levels. The response rate was 93%. The diagnoses and types of arthroscopic surgery were similar in both groups. In total, 94% of day-cases and 91% of patients admitted overnight expressed overall satisfaction. Pain after discharge was similar in both groups. Day-case management was preferred by 90% of day-case patients and by 64% of those admitted overnight. Of patients in the day-case group, 12% had to be admitted overnight because of recovery problems, but 7% of patients randomised to overnight stay discharged themselves. One patient admitted overnight required readmission because of a wound haematoma. Patients who had received day-case management returned to work significantly faster than those who had been admitted. Modern anaesthetic techniques with special attention to anti-emesis and pain control have reduced postoperative morbidity to acceptable levels. Provided that patients are properly selected and well informed, day-case care is preferable for the majority of patients undergoing arthroscopic surgery of the knee.

Kinematic posterior cruciate ligament-retaining total knee replacements. A 10-year survivorship study of 445 arthroplasties.

Survival was tested in 445 primary Kinematic knee replacements performed between January 1981 and December 1990. Three criteria were applied to indicate failure: 1) revision or recommended revision, 2) presence of moderate to severe pain or revision, and 3) lost to follow-up or revision. Using these three criteria, the survival rate at 10 years was 96%, 78%, and 69%, respectively. At last follow-up examination, 84% of knees had good or excellent Bristol knee scores with mean range of motion 100 degrees. Overall, 11 knees (2.5%) have been revised and 27 cases (6%) were graded as failures due to presence of moderate to severe pain at the time of the last evaluation. These results indicate that the posterior cruciate ligament-retaining Kinematic prosthesis provides satisfactory function and survival up to 10 years.

Revision of unicompartmental arthroplasty of the knee. Clinical and technical considerations.

In 73 unicompartmental arthroplasties of the knee that were revised, the major causes of failure were progression of arthritis and implant failure. The interval between the primary and revision averaged 56 months. Eighty-eight percent were revised to a variety of total condylar prostheses. Bone loss was classified by defect at the end of preparation. In 31 patients, there were none; in 17, the defect was in either the femur or the tibia; and in 25, there were defects in both the femur and the tibia. Forty-seven of these defects were small and contained, presenting little problem. Twenty defects were either large, contained, or peripheral, requiring reconstruction. Fifteen knees were lost as a result of death (but there had been satisfactory knee function); 2 were lost to follow-up evaluation, and 3 have required further revision. Seventy-nine percent of the surviving knees had excellent or good knee function at an average follow-up period of 56 months.

Assessment of the menisci and cruciate ligaments: an audit of clinical practice.

The reliability of clinical assessment of the knee was evaluated in 203 patients using magnetic resonance imaging (MRI). Neither the mechanism of injury nor clinical symptoms were useful indicators of the type of pathology. Physical signs proved insufficiently sensitive in detecting abnormalities. Overall, the accuracy of clinical diagnosis was 80.8 per cent for the anterior cruciate ligament, 62.9 per cent for the medial meniscus and 74.9 per cent for the lateral meniscus. Accurate investigations allow arthroscopy to be targeted to those likely to obtain therapeutic benefit. Reliance upon clinical judgement alone would have resulted in an 89 per cent increase in arthroscopic procedures. Investigations such as MRI or arthrography are concluded to be cost-effective methods of avoiding unnecessary hospitalization, morbidity and waste of limited resources.

Magnetic resonance imaging of meniscal and cruciate injuries of the knee.

We investigated 133 knees with suspected meniscal or cruciate injuries by magnetic resonance imaging, and compared the findings with those at arthroscopy. MRI was found to be highly sensitive, specific and accurate in the evaluation of the menisci and the anterior cruciate ligament.

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.