We assessed the unloading effect of the patellar tendon-bearing (PTB) cast in five healthy volunteers using a new system for analysis of dynamic plantar pressure. We devised a method to improve the unloading effect of the PTB cast, and tested this using the same system. Our findings showed that the conventional PTB cast only achieved unloading of 30% of the body-weight and that the part of the cast on the leg had a more important role in the unloading than that which was in contact with the patellar tendon. When the depth of the free space under the foot inside the PTB cast was 1, 2 and 3 cm, the unloading effect was 60%, 80% and 98%, respectively. The unloading effect of the conventional PTB cast was disappointing at only 30% of body-weight. It was improved by producing a space between the sole of the foot and the cast, and was adjustable by altering the depth of this space

Aims

The aim of this study was to evaluate medium- to long-term outcomes and complications of the Stanmore Modular Individualised Lower Extremity System (SMILES) rotating hinge implant in revision total knee arthroplasty (rTKA) at a tertiary unit. It is hypothesized that this fully cemented construct leads to satisfactory clinical outcomes.

Aims

One of the main causes of tibial revision surgery for total knee arthroplasty is aseptic loosening. Therefore, stable fixation between the tibial component and the cement, and between the tibial component and the bone, is essential. A factor that could influence the implant stability is the implant design, with its different variations. In an existing implant system, the tibial component was modified by adding cement pockets. The aim of this experimental in vitro study was to investigate whether additional cement pockets on the underside of the tibial component could improve implant stability. The relative motion between implant and bone, the maximum pull-out force, the tibial cement mantle, and a possible path from the bone marrow to the metal-cement interface were determined.

Aims

The aims of this study were to evaluate wear on the surface of cobalt-chromium (CoCr) femoral components used in total knee arthroplasty (TKA) and compare the wear of these components with that of ceramic femoral components.

Twenty complex tibial deformities due to anterior poliomyelitis in 18 patients were corrected by a modified O’Donoghue osteotomy. This technique allowed correction of the deformity in three planes. This was achieved by widening the rectangular window distally to correct both rotation and valgus and by trimming the anterior edges of the step cuts to correct flexion deformity. An above-knee cast was applied for eight to 13 weeks and the patients followed up for a mean of 3.2 years. One of the 18 patients developed delayed union because of fracture of the medial limb of the step cut. The results showed excellent correction of the three-plane deformity and there was no recurrence. This method of osteotomy is a safe and simple procedure which does not require internal fixation and allows correction of torsional and angular deformity

Aims

Arthrodesis is rarely used as a salvage procedure for patients with a chronically infected total knee arthroplasty (TKA), and little information is available about the outcome. The aim of this study was to assess the reliability, durability, and safety of this procedure as the definitive treatment for complex, chronically infected TKA, in a current series of patients.

Aims

The aim of this study was to report the outcome of femoral condylar fresh osteochondral allografts (FOCA) with concomitant realignment osteotomy with a focus on graft survivorship, complications, reoperation, and function.

Patellar instability most frequently presents during adolescence. Congenital and infantile dislocation of the patella is a distinct entity from adolescent instability and measurable abnormalities may be present at birth. In the normal patellofemoral joint an increase in quadriceps angle and patellar height are matched by an increase in trochlear depth as the joint matures. Adolescent instability may herald a lifelong condition leading to chronic disability and arthritis.

Restoring normal anatomy by trochleoplasty, tibial tubercle transfer or medial patellofemoral ligament (MPFL) reconstruction in the young adult prevents further instability. Although these techniques are proven in the young adult, they may cause growth arrest and deformity where the physis is open. A vigorous non-operative strategy may permit delay of surgery until growth is complete. Where non-operative treatment has failed a modified MPFL reconstruction may be performed to maintain stability until physeal closure permits anatomical reconstruction. If significant growth remains an extraosseous reconstruction of the MPFL may impart the lowest risk to the physis. If minor growth remains image intensifier guided placement of femoral intraosseous fixation may impart a small, but acceptable, risk to the physis.

This paper presents and discusses the literature relating to adolescent instability and provides a framework for management of these patients.

Cite this article: Bone Joint J 2017;99-B:159–70.

Objectives

The purpose of this study was to clarify the appearance of the reparative tissue on the articular surface and to analyse the properties of the reparative tissue after hemicallotasis osteotomy (HCO) using MRI T1ρ and T2 mapping.

Osteochondritis Dissecans (OCD) is a condition for which the aetiology remains unknown. It affects subchondral bone and secondarily its overlying cartilage and is mostly found in the knee. It can occur in adults, but is generally identified when growth remains, when it is referred to as juvenile OCD. As the condition progresses, the affected subchondral bone separates from adjacent healthy bone, and can lead to demarcation and separation of its associated articular cartilage. Any symptoms which arise relate to the stage of the disease. Early disease without separation of the lesion results in pain. Separation of the lesion leads to mechanical symptoms and swelling and, in advanced cases, the formation of loose bodies.

Early identification of OCD is essential as untreated OCD can lead to the premature degeneration of the joint, whereas appropriate treatment can halt the disease process and lead to healing. Establishing the stability of the lesion is a key part of providing the correct treatment. Stable lesions, particularly in juvenile patients, have greater propensity to heal with non-surgical treatment, whereas unstable or displaced lesions usually require surgical management.

This article discusses the aetiology, clinical presentation and prognosis of OCD in the knee. It presents an algorithm for treatment, which aims to promote healing of native hyaline cartilage and to ensure joint congruity.

Take home message: Although there is no clear consensus as to the best treatment of OCD, every attempt should be made to retain the osteochondral fragment when possible as, with a careful surgical technique, there is potential for healing even in chronic lesions

Cite this article: Bone Joint J 2016;98-B:723–9.

Although the vast majority of patients that undergo total knee replacement have satisfactory outcomes with a generally low complication rate, occasionally a patient will be encountered that has had multiple failed surgeries, and now reaches a crossroad as to whether limb salvage will be acceptable or not.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):122–4.

An increased tibial tubercle–trochlear groove (TT-TG) distance is related to patellar maltracking and instability. Tibial tubercle transfer is a common treatment option for these patients with good short-term results, although the results can deteriorate over time owing to the progression of osteoarthritis. We present a ten-year follow-up study of a self-centring tibial tubercle osteotomy in 60 knees, 30 with maltracking and 30 with patellar instability. Inclusion criteria were a TT-TG ≥ 15 mm and symptoms for > one year. One patient (one knee) was lost to follow-up and one required total knee arthroplasty because of progressive osteoarthritis. Further patellar dislocations occurred in three knees, all in the instability group, one of which required further surgery. The mean visual analogue scores for pain, and Lysholm and Kujala scores improved significantly and were maintained at the final follow-up (repeated measures, p = 0.000, intergroup differences p = 0.449). Signs of maltracking were found in only a minority of patients, with no difference between groups (p > 0.05). An increase in patellofemoral osteoarthritis was seen in 16 knees (31%) with a maximum of grade 2 on the Kellgren–Lawrence scale. The mean increase in grades was 0.31 (0 to 2) and 0.41 (0 to 2) in the maltracking and instability groups respectively (p = 0.2285)

This self-centring tibial tubercle osteotomy provides good results at ten years’ follow-up without inducing progressive osteoarthritis.

Cite this article: Bone Joint J 2015;97-B:329–36.

We report the results of revision total knee replacement (TKR) in 26 patients with major metaphyseal osteolytic defects using 29 trabecular metal cones in conjunction with a rotating hinged total knee prosthesis. The osteolytic defects were types II and III (A or B) according to the Anderson Orthopaedic Research Institute (AORI) classification. The mean age of the patients was 72 years (62 to 84) and there were 15 men and 11 women. In this series patients had undergone a mean of 2.34 previous total knee arthroplasties. The main objective was to restore anatomy along with stability and function of the knee joint to allow immediate full weight-bearing and active knee movement. Outcomes were measured using Knee Society scores, Oxford knee scores, range of movement of the knee and serial radiographs. Patients were followed for a mean of 36 months (24 to 49). The mean Oxford knee clinical scores improved from 12.83 (10 to 15) to 35.20 (32 to 38) (p < 0.001) and mean American Knee Society scores improved from 33.24 (13 to 36) to 81.12 (78 to 86) (p < 0.001). No radiolucent lines suggestive of loosening were seen around the trabecular metal cones, and by one year all the radiographs showed good osteo-integration. There was no evidence of any collapse or implant migration. Our early results confirm the findings of others that trabecular metal cones offer a useful way of managing severe bone loss in revision TKR.

Cite this article: Bone Joint J 2013;95-B:1069–74.

Disruption of the extensor mechanism in total knee arthroplasty may occur by tubercle avulsion, patellar or quadriceps tendon rupture, or patella fracture, and whether occurring intra-operatively or post-operatively can be difficult to manage and is associated with a significant rate of failure and associated complications. This surgery is frequently performed in compromised tissues, and repairs must frequently be protected with cerclage wiring and/or augmentation with local tendon (semi-tendinosis, gracilis) which may also be used to treat soft-tissue loss in the face of chronic disruption. Quadriceps rupture may be treated with conservative therapy if the patient retains active extension. Component loosening or loss of active extension of 20° or greater are clear indications for surgical treatment of patellar fracture. Acute patellar tendon disruption may be treated by primary repair. Chronic extensor failure is often complicated by tissue loss and retraction can be treated with medial gastrocnemius flaps, achilles tendon allografts, and complete extensor mechanism allografts. Attention to fixing the graft in full extension is mandatory to prevent severe extensor lag as the graft stretches out over time.

The lateral compartment is predominantly affected in approximately 10% of patients with osteoarthritis of the knee. The anatomy, kinematics and loading during movement differ considerably between medial and lateral compartments of the knee. This in the main explains the relative protection of the lateral compartment compared with the medial compartment in the development of osteoarthritis. The aetiology of lateral compartment osteoarthritis can be idiopathic, usually affecting the femur, or secondary to trauma commonly affecting the tibia. Surgical management of lateral compartment osteoarthritis can include osteotomy, unicompartmental knee replacement and total knee replacement. This review discusses the biomechanics, pathogenesis and development of lateral compartment osteoarthritis and its management.

Cite this article: Bone Joint J 2013;95-B:436–44.

Cartilage repair in terms of replacement, or regeneration of damaged or diseased articular cartilage with functional tissue, is the ‘holy grail’ of joint surgery. A wide spectrum of strategies for cartilage repair currently exists and several of these techniques have been reported to be associated with successful clinical outcomes for appropriately selected indications. However, based on respective advantages, disadvantages, and limitations, no single strategy, or even combination of strategies, provides surgeons with viable options for attaining successful long-term outcomes in the majority of patients. As such, development of novel techniques and optimisation of current techniques need to be, and are, the focus of a great deal of research from the basic science level to clinical trials. Translational research that bridges scientific discoveries to clinical application involves the use of animal models in order to assess safety and efficacy for regulatory approval for human use. This review article provides an overview of animal models for cartilage repair.

Cite this article: Bone Joint Res 2014;4:89–94.

We investigated the role of a functional brace worn for four months in the treatment of patients with an acute isolated tear of the posterior cruciate ligament to determine whether reduction of the posterior tibial translation during the healing period would give an improved final position of the tibia. The initial and follow-up stability was tested by Rolimeter arthrometry and radiography. The clinical outcome was evaluated using the Lysholm score, the Tegner score and the International Knee Documentation Committee scoring system at follow-up at one and two years. In all, 21 patients were studied, 21 of whom had completed one-year and 17 a two-year follow-up.

The initial mean posterior sag (Rolimeter measurement) of 7.1 mm (5 to 10) was significantly reduced after 12 months to a mean of 2.3 mm (0 to 6, p < 0.001) and to a mean of 3.2 mm (2 to 7, p = 0.001) after 24 months. Radiological measurement gave similar results. The mean pre-injury Lysholm score was normal at 98 (95 to 100). At follow-up, a slight decrease in the mean values was observed to 94.0 (79 to 100, p = 0.001) at one year and 94.0 (88 to 100, p = 0.027, at two years).

We concluded that the posterior cruciate ligament has an intrinsic healing capacity and, if the posteriorly translated tibia is reduced to a physiological position, it can heal with less attentuation. The applied treatment produces a good to excellent functional result.

A prospective, randomised, controlled trial compared two different techniques of high tibial osteotomy with a lateral closing wedge or a medial opening wedge, stabilised by a Puddu plate. The clinical outcome and radiological results were examined at one year.

The primary outcome measure was the achievement of an overcorrection of valgus of 4°. Secondary outcome measures were the severity of pain (visual analogue scale), knee function (Hospital for Special Surgery score), and walking distance.

Between January 2001 and April 2004, 92 patients were randomised to one or other of the techniques. At follow-up at one year the post-operative hip-knee-ankle angle was 3.4° (± 3.6° sd) valgus after a closing wedge and 1.3° (± 4.7° sd) of valgus after an opening wedge. The adjusted mean difference of 2.1° was significant (p = 0.02). The deviation from 4° of valgus alignment was 2.7° (± 2.4° sd) in the closing wedge and 4.0° (± 3.6° sd) in the opening-wedge groups. The adjusted mean difference of 1.67° was also significant (p = 0.01).

The severity of pain, knee score and walking ability improved in both groups, but the difference was not significant.

Because of pain, the staples required removal in 11 (23%) patients in the closing-wedge group and a Puddu plate was removed in 27 (60%) patients in the opening-wedge group. This difference was significant (p < 0.001).

We conclude that closing-wedge osteotomy achieves a more accurate correction with less morbidity, although both techniques had improved the function of the knee at one year after the procedure.

The management of failed autologous chondrocyte implantation (ACI) and matrix-assisted autologous chondrocyte implantation (MACI) for the treatment of symptomatic osteochondral defects in the knee represents a major challenge. Patients are young, active and usually unsuitable for prosthetic replacement. This study reports the results in patients who underwent revision cartilage transplantation of their original ACI/MACI graft for clinical or graft-related failure. We assessed 22 patients (12 men and 10 women) with a mean age of 37.4 years (18 to 48) at a mean of 5.4 years (1.3 to 10.9). The mean period between primary and revision grafting was 46.1 months (7 to 89). The mean defect size was 446.6 mm² (150 to 875) and they were located on 11 medial and two lateral femoral condyles, eight patellae and one trochlea.

The mean modified Cincinnati knee score improved from 40.5 (16 to 77) pre-operatively to 64.9 (8 to 94) at their most recent review (p < 0.001). The visual analogue pain score improved from 6.1 (3 to 9) to 4.7 (0 to 10) (p = 0.042). A total of 14 patients (63%) reported an ‘excellent’ (n = 6) or ‘good’ (n = 8) clinical outcome, 5 ‘fair’ and one ‘poor’ outcome. Two patients underwent patellofemoral joint replacement. This study demonstrates that revision cartilage transplantation after primary ACI and MACI can yield acceptable functional results and continue to preserve the joint.

Cite this article: Bone Joint J 2014;96-B:54–8.

Our aim was to compare the degree of patellar descent and alteration in angle of the inclination of the tibial plateau in lateral closing-wedge and medial opening-wedge high tibial osteotomy (HTO) in 51 consecutive patients with osteoarthritis of the medial compartment and varus malalignment. Patellar height was measured by the Insall-Salvati (IS) and the Blackburne-Peel (BP) ratios. The tibial inclination was determined by the Moore-Harvey (MH) method. Multivariate linear regression analysis was used to determine the influence of the type of HTO (closing vs opening wedge) on the post-operative patellar height or tibial inclination. The intra- and interobserver variability of these methods was determined before operation and at follow-up at one year.

After an opening-wedge HTO the patellar height was significantly more decreased (mean post-operative difference: IS = 0.15; 95% confidence interval (CI) 0.06 to 0.23; BP = 0.11; 95% CI 0.05 to 0.18) compared with a closing-wedge HTO.

The angle of tibial inclination differed significantly (mean post-operative difference MH = −6.40°; 95% CI −8.74 to −4.02) between the two HTO techniques, increasing after opening-wedge HTO and decreasing after closing-wedge HTO.

There was no clinically-relevant difference in the intra- and interobserver variability of measurements of patellar height either before or after HTO.

We report the outcome of 32 patients (37 knees) who underwent hemicallostasis with a dynamic external fixator for osteoarthritis of the medial compartment of the knee. There were 16 men (19 knees) and 16 women (18 knees) with a mean age at operation of 54.6 years (27 to 72). The aim was to achieve a valgus overcorrection of 2° to 8° or mechanical axis at 62.5% (± 12.5%). At a mean follow-up of 62.8 months (51 to 81) there was no change in the mean range of movement, and no statistically significant difference in the Insall-Salvati index or tibial slope (p = 0.11 and p = 0.15, respectively). The mean hip-knee-ankle angle changed from 190.6 (183° to 197°) to 176.0° (171° to 181°), with a mean final position of the mechanical axis of 58.5% (35.1% to 71.2%).

The desired alignment was attained in 31 of 37 (84%) knees. There were 21 excellent, 13 good, two fair and one poor result according to the Oxford knee score with no correlation between age and final score. This score was at its best at one year with a statistically significant deterioration at two years (p = 0.001) followed by a small but not statistically significant deterioration until the final follow-up (p = 0.17). All the knees with Ahlback grade 1 osteoarthritis had excellent or good results. Complications included pin tract infections involving 16.4% of all pins used, delayed union in two, knee stiffness in four, fracture of the lateral cortex in one and ring sequestrum in one.

In conclusion, hemicallostasis provides precision in attaining the desired alignment without interfering with tibial slope or patellar height, and is relatively free of serious complications.

Isolated patellofemoral osteoarthritis can be a disabling disease. When conservative treatment fails, surgical options can be unpredictable and may be considered too aggressive for middle-aged and active people. We analysed the clinical and radiological results of a new coronal osteotomy involving thinning of the patella in a selected group of patients with isolated patellofemoral osteoarthritis. Since 1991, 31 patients (35 knees) have been treated, of whom 34 were available for follow-up at a mean of 9.1 years. The Knee Society Score, the Patellar score and the Short-form-36 questionnaire were used for clinical evaluation. We also examined the radiological features to confirm bone consolidation and assess the progression of osteoarthritis. A significant improvement in the functional scores and radiological parameters was noted. All patients except one were satisfied with the operation. Radiological progression of the patellofemoral osteoarthritis was slowed but radiological femorotibial osteoarthritis progressed in 23 (65%) cases, with a total knee replacement becoming necessary in four cases without technical problems in resurfacing the patella. We compared the results with other forms of surgical treatment reported in the literature.

This treatment offers good clinical and radiological results, presenting an alternative method of managing patellofemoral osteoarthritis.

Antibiotic impregnated articulating spacers are used in two-stage revision total knee arthroplasty to deliver local antibiotic therapy while preserving function. We have observed infection control in greater than 95% of cases with functional outcomes approaching those seen in revision for aseptic loosening. Higher failure has been observed with methicillin resistant organisms.

We compared the incidence and severity of complications during and after closing- and opening-wedge high tibial osteotomy used for the treatment of varus arthritis of the knee, and identified the risk factors associated with the development of complications. In total, 104 patients underwent laterally based closing-wedge and 90 medial opening-wedge high tibial osteotomy between January 1993 and December 2006. The characteristics of each group were similar. All the patients were followed up for more than 12 months. We assessed the outcome using the Hospital for Special Surgery knee score, and recorded the complications. Age, gender, obesity (body mass index > 27.5 kg/m²), the type of osteotomy (closing versus opening) and the pre-operative mechanical axis were subjected to risk-factor analysis.

The mean Hospital for Special Surgery score in the closing and opening groups improved from 73.4 (54 to 86) to 91.8 (81 to 100) and from 73.8 (56 to 88) to 93 (84 to 100), respectively. The incidence of complications overall and of major complications in both groups was not significantly different (p = 0.20 overall complication, p = 0.29 major complication). Logistic regression analysis adjusting for obesity and the pre-operative mechanical axis showed that obesity remained a significant independent risk factor (odds ratio = 3.23) of a major complication after high tibial osteotomy.

Our results suggest that the opening-wedge high tibial osteotomy can be an alternative treatment option for young patients with medial compartment osteoarthritis and varus deformity.

We retrospectively reviewed the operative treatment carried out between 1988 and 1994 of eight patients with habitual patellar dislocation. In four the condition was bilateral. All patients had recurrent dislocation with severe functional disability. The surgical technique involved distal advancement of the patella by complete mobilisation of the patellar tendon, lateral release and advancement of vastus medialis obliquus. The long-term results were assessed radiologically, clinically and functionally using the Lysholm knee score, by an independent observer.

The mean age at operation was 10.3 years (7 to 14) with a mean follow-up of 13.5 years (11 to 16). One patient required revision. At the latest follow-up, all patellae were stable and knees functional with a mean Lysholm knee score of 98 points (95 to 100). In those aged younger than ten years at operation there was a statistically significant improvement in the sulcus angle at the latest follow-up (Student’s t-test, p = 0.001). Two patients developed asymptomatic patella infera as a late complication.

This technique offers a satisfactory treatment for the immature patient presenting with habitual patellar dislocation associated with patella alta. If performed early, we believe that remodelling of the shallow trochlea may occur, adding intrinsic patellofemoral stability.

We systematically reviewed the published literature on the complications of closing wedge high tibial osteotomy for the treatment of unicompartmental osteoarthritis of the knee. Publications were identified using the Cochrane Library, MEDLINE, EMBASE and CINAHL databases up to February 2012. We assessed randomised (RCTs), controlled group clinical (CCTs) trials, case series in publications associated with closing wedge osteotomy of the tibia in patients with osteoarthritis of the knee and finally a Cochrane review. Many of these trials included comparative studies (opening wedge versus closing wedge) and there was heterogeneity in the studies that prevented pooling of the results.

In this paper, we consider wound healing after total knee arthroplasty.

We retrospectively evaluated eight patients who underwent arthrodesis of the knee using cannulated screws. There were six women and two men, with a mean age of 53 years. The indications for arthrodesis were failed total knee arthroplasty, septic arthritis, tuberculosis, and recurrent persistent infection. Solid union was achieved in all patients at a mean of 6.1 months. One patient required autogenous bone graft for delayed union. One suffered skin necrosis which was treated with skin grafting. The mean limb-length discrepancy was 3.1 cm. On a visual analogue scale, the mean pain score improved from 7.9 to 3.3. According to the Knee Injury and Osteoarthritis Outcome score quality of life items, the mean score improved from 38.3 pre-operatively to 76.6 at follow-up. Cannulated screws provide a high rate of union in arthrodesis of the knee with minimal complications, patient convenience, and a simple surgical technique.

Matrix-induced autologous chondrocyte implantation (MACI) is an established technique used to treat osteochondral lesions in the knee. For larger osteochondral lesions (> 5 cm²) deeper than approximately 8 mm we have combined the use of two MACI membranes with impaction grafting of the subchondral bone. We report our results of 14 patients who underwent the ‘bilayer collagen membrane’ technique (BCMT) with a mean follow-up of 5.2 years (2 to 8). There were 12 men and two women with a mean age of 23.6 years (16 to 40). The mean size of the defect was 7.2 cm² (5.2 to 12 cm²) and were located on the medial (ten) or lateral (four) femoral condyles. The mean modified Cincinnati knee score improved from 45.1 (22 to 70) pre-operatively to 82.8 (34 to 98) at the most recent review (p < 0.05). The visual analogue pain score improved from 7.3 (4 to 10) to 1.7 (0 to 6) (p < 0.05). Twelve patients were considered to have a good or excellent clinical outcome. One graft failed at six years.

The BCMT resulted in excellent functional results and durable repair of large and deep osteochondral lesions without a high incidence of graft-related complications.

Autologous chondrocyte implantation (ACI) and mosaicplasty are methods of treating symptomatic articular cartilage defects in the knee. This study represents the first long-term randomised comparison of the two techniques in 100 patients at a minimum follow-up of ten years. The mean age of the patients at the time of surgery was 31.3 years (16 to 49); the mean duration of symptoms pre-operatively was 7.2 years (9 months to 20 years). The lesions were large with the mean size for the ACI group being 440.9 mm² (100 to 1050) and the mosaicplasty group being 399.6 mm² (100 to 2000). Patients had a mean of 1.5 previous operations (0 to 4) to the articular cartilage defect. Patients were assessed using the modified Cincinnati knee score and the Stanmore-Bentley Functional Rating system. The number of patients whose repair had failed at ten years was ten of 58 (17%) in the ACI group and 23 of 42 (55%) in the mosaicplasty group (p < 0.001).

The functional outcome of those patients with a surviving graft was significantly better in patients who underwent ACI compared with mosaicplasty (p = 0.02).

An abnormal lateral position of the tibial tuberosity causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking of the patella causing anterior knee pain or objective patellar instability, characterised by recurrent dislocation. Computer tomography is used for a precise pre-operative assessment of the tibial tubercle-trochlear groove distance. A distance of more than 15 mm is considered to be pathological and an indication for surgery in symptomatic patients.

In a prospective study we performed a subtle transfer of the tibial tuberosity according to the information gained from the pre-operative CT scan. This method was applied to two groups of patients, those with painful lateral tracking of the patella, and those with objective patellar instability. We evaluated the clinical results in 30 patients in each group. The outcome was documented at 3, 12 and 24 months using the Lysholm scale, the Kujala score, and a visual analogue pain score.

Post-operatively, all but one patient in the instability group who had a patellar dislocation requiring further surgery reported good improvement with no further subluxation or dislocation. All patients in both groups had a marked improvement in pain and functional score. Two patients sustained a tibial fracture six and seven weeks after surgery. One patient suffered a per-operative fracture of the tibial tubercle which later required further fixation.

If carefully performed, this type of transfer of the tibial tubercle appears to be a satisfactory technique for the treatment of patients with an increased tibial tubercle-trochlear groove distance and who present with symptoms related to lateral maltracking of the patella.

Autologous chondrocyte implantation (ACI) is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes. We have performed a prospective, randomised comparison of ACI-C and MACI for the treatment of symptomatic chondral defects of the knee in 91 patients, of whom 44 received ACI-C and 47 MACI grafts.

Both treatments resulted in improvement of the clinical score after one year. The mean modified Cincinnati knee score increased by 17.6 in the ACI-C group and 19.6 in the MACI group (p = 0.32). Arthroscopic assessments performed after one year showed a good to excellent International Cartilage Repair Society score in 79.2% of ACI-C and 66.6% of MACI grafts. Hyaline-like cartilage or hyaline-like cartilage with fibrocartilage was found in the biopsies of 43.9% of the ACI-C and 36.4% of the MACI grafts after one year. The rate of hypertrophy of the graft was 9% (4 of 44) in the ACI-C group and 6% (3 of 47) in the MACI group. The frequency of re-operation was 9% in each group.

We conclude that the clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI. While MACI is technically attractive, further long-term studies are required before the technique is widely adopted.

We carried out a prospective study of 132 patients (159 knees) who underwent closed-wedge high tibial osteotomy for severe medial compartment osteoarthritis between 1988 and 1997. A total of 94 patients (118 knees) was available for review at a mean of 16.4 years (16 to 20). Seven patients (7.4%) (11 knees) required conversion to total knee replacement. Kaplan-Meier survival was 97.6% (95% confidence interval 95.0 to 100) at ten years and 90.4% (95% confidence interval 84.1 to 96.7) at 15 years. Excellent and good results as assessed by the Hospital for Special Surgery knee score were achieved in 87 knees (73.7%). A pre-operative body mass index > 27.5 kg/m² and range of movement < 100° were risk factors predicting early failure.

Although our long-term results were satisfactory, strict indications for osteotomy are required if long-term survival is required.

We undertook a prospective randomised controlled trial to investigate the efficacy of autologous retransfusion drains in reducing the need for allogenic blood requirement after unilateral total knee replacement. We also monitored the incidence of post-operative complications. There were 86 patients in the control group, receiving standard care with a vacuum drain, and 92 who received an autologous drain and were retransfused postoperatively. Following serial haemoglobin measurements at 24, 48 and 72 hours, we found no difference in the need for allogenic blood between the two groups (control group 15.1%, retransfusion group 13% (p = 0.439)). The incidence of post-operative complications, such as wound infection, deep-vein thrombosis and chest infection, was also comparable between the groups. There were no adverse reactions associated with the retransfusion of autologous blood.

Based on this study, the cost-effectiveness and continued use of autologous drains in total knee replacement should be questioned.

We prospectively studied the clinical, arthroscopic and histological results of collagen-covered autologous chondrocyte implantation (ACI-C) in patients with symptomatic osteochondritis dissecans of the knee. The study included 37 patients who were evaluated at a mean follow-up of 4.08 years.

Clinical results showed a mean improvement in the modified Cincinnati score from 46.1 to 68.4. Excellent and good clinical results were seen in 82.1% of those with juvenile-onset osteochondritis dissecans but in only 44.4% of those with adult-onset disease.

Arthroscopy at one year revealed International Cartilage Repair Society grades of 1 or 2 in 21 of 24 patients (87.5%). Of 23 biopsies, 11 (47.8%) showed either a hyaline-like or a mixture of hyaline-like and fibrocartilage, 12 (52.2%) showed fibrocartilage.

The age at the time of ACI-C determined the clinical outcome for juvenile-onset disease (p = 0.05), whereas the size of the defect was the major determinant of outcome in adult-onset disease (p = 0.01).

Autologous chondrocyte implantation (ACI) is a technique used for the treatment of symptomatic osteochondral defects of the knee. A variation of the original periosteum membrane technique is the matrix-induced autologous chondrocyte implantation (MACI) technique. The MACI membrane consists of a porcine type-I/III collagen bilayer seeded with chondrocytes. Osteochondral defects deeper than 8 to 10 mm usually require bone grafting either before or at the time of transplantation of cartilage. We have used a variation of Peterson’s ACI-periosteum sandwich technique using two MACI membranes with bone graft which avoids periosteal harvesting. The procedure is suture-free and requires less operating time and surgical exposure. We performed this MACI-sandwich technique on eight patients, five of whom were assessed at six months and one year post-operatively using the modified Cincinnati knee, the Stanmore functional rating and the visual analogue pain scores.

All patients improved within six months with further improvement at one year. The clinical outcome was good or excellent in four after six months and one year. No significant graft-associated complications were observed. Our early results of the MACI-sandwich technique are encouraging although larger medium-term studies are required before there is widespread adoption of the technique.

A postal questionnaire was sent to 10 000 patients more than one year after their total knee replacement (TKR). They were assessed using the Oxford knee score and were asked whether they were satisfied, unsure or unsatisfied with their TKR. The response rate was 87.4% (8231 of 9417 eligible questionnaires) and a total of 81.8% (6625 of 8095) of patients were satisfied. Multivariable regression modelling showed that patients with higher scores relating to the pain and function elements of the Oxford knee score had a lower level of satisfaction (p < 0.001), and that ongoing pain was a stronger predictor of this. Female gender and a primary diagnosis of osteoarthritis were found to be predictors of lower levels of patient satisfaction. Differences in the rate of satisfaction were also observed in relation to age, the American Society of Anesthesiologists grade and the type of prosthesis.

This study has provided data on the Oxford knee score and the expected levels of satisfaction at one year after TKR. The results should act as a benchmark of practice in the United Kingdom and provide a baseline for peer comparison between institutions.

Clinical experience of impaction bone grafting for revision knee arthroplasty is limited, with initial stability of the tibial tray emerging as a major concern. The length of the stem and its diameter have been altered to improve stability. Our aim was to investigate the effect of the type of stem, support of the rim and graft impaction on early stability of the tray.

We developed a system for impaction grafting of trays which we used with morsellised bone in artificial tibiae. Trays with short, long thick or long thin stems were implanted, with or without support of the rim. They were cyclically loaded while measuring relative movement.

Long-stemmed trays migrated 4.5 times less than short-stemmed trays, regardless of diameter. Those with support migrated 2.8 times less than those without. The migration of short-stemmed trays correlated inversely with the density of the impacted groups. That of impaction-grafted tibial trays was in the range reported for uncemented primary trays. Movements of short-stemmed trays without cortical support were largest and sensitive to the degree of compaction of the graft. If support of the rim was sufficient or a long stem was used, impacted morsellised bone graft achieved adequate initial stability.