The purpose of this study was to evaluate the long-term functional and radiological outcomes of arthroscopic removal of unstable osteochondral lesions with subchondral drilling in the lateral femoral condyle. We reviewed the outcome of 23 patients (28 knees) with stage III or IV osteochondritis dissecans lesions of the lateral femoral condyle at a mean follow-up of 14 years (10 to 19). The functional clinical outcomes were assessed using the Lysholm score, which improved from a mean of 38.1 (sd 3.5) pre-operatively to a mean of 87.3 (sd 5.4) at the most recent review (p = 0.034), and the Tegner activity score, which improved from a pre-operative median of 2 (0 to 3) to a median of 5 (3 to 7) at final follow-up (p = 0.021). The radiological degenerative changes were evaluated according to Tapper and Hoover’s classification and when compared with the pre-operative findings, one knee had grade 1, 22 knees had grade 2 and five knees had grade 3 degenerative changes. The overall outcomes were assessed using Hughston’s rating scale, where 19 knees were rated as good, four as fair and five as poor.

We found radiological evidence of degenerative changes in the third or fourth decade of life at a mean of 14 years after arthroscopic excision of the loose body and subchondral drilling for an unstable osteochondral lesion of the lateral femoral condyle. Clinical and functional results were more satisfactory.

Aims. The aims of this study were to determine the effect of osteophyte excision on deformity correction and soft tissue gap balance in varus knees undergoing computer-assisted total knee arthroplasty (TKA). Methods. A total of 492 consecutive, cemented, cruciate-substituting TKAs performed for varus osteoarthritis were studied. After exposure and excision of both cruciates and menisci, it was noted from operative records the corrective interventions performed in each case. Knees in which no releases after the initial exposure, those which had only osteophyte excision, and those in which further interventions were performed were identified. From recorded navigation data, coronal and sagittal limb alignment, knee flexion range, and medial and lateral gap distances in maximum knee extension and 90° knee flexion with maximal varus and valgus stresses, were established, initially after exposure and excision of both cruciate ligaments, and then also at trialling. Knees were defined as ‘aligned’ if the hip-knee-ankle axis was between 177° and 180°, (0° to 3° varus) and ‘balanced’ if medial and lateral gaps in extension and at 90° flexion were within 2 mm of each other. Results. Of 50 knees (10%) with no soft tissue releases (other than cruciate ligaments), 90% were aligned, 81% were balanced, and 73% were aligned and balanced. In 288 knees (59%) only osteophyte excision was performed by subperiosteally releasing the deep medial collateral ligament. Of these, 98% were aligned, 80% were balanced, and 79% were aligned and balanced. In 154 knees (31%), additional procedures were performed (reduction osteotomy, posterior capsular release, and semimembranosus release). Of these, 89% were aligned, 68% were balanced, and 66% were aligned and balanced. The superficial medial collateral ligament was not released in any case. Conclusion. Two-thirds of all knees could be aligned and balanced with release of the cruciate ligaments alone and excision of osteophytes. Excision of osteophytes can be a useful step towards achieving deformity correction and gap balance without having to resort to soft tissue release in varus knees while maintaining classical coronal and sagittal alignment of components. Cite this article: Bone Joint J 2020;102-B(6 Supple A):49–58

Aims

While residual fixed flexion deformity (FFD) in unicompartmental knee arthroplasty (UKA) has been associated with worse functional outcomes, limited evidence exists regarding FFD changes. The objective of this study was to quantify FFD changes in patients with medial unicompartmental knee arthritis undergoing UKA, and investigate any correlation with clinical outcomes.

Aims

Knowledge on total knee arthroplasties (TKAs) in patients with a history of poliomyelitis is limited. This study compared implant survivorship and clinical outcomes among affected and unaffected limbs in patients with sequelae of poliomyelitis undergoing TKAs.

Aims

Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) have both been shown to be effective treatments for osteoarthritis (OA) of the knee. Many studies have compared the outcomes of the two treatments, but less so with the use of robotics, or individualized TKA alignment techniques. Functional alignment (FA) is a novel technique for performing a TKA and shares many principles with UKA. Our aim was to compare outcomes from a case-matched series of robotic-assisted UKAs and robotic-assisted TKAs performed using FA.

Aims

Periprosthetic joint infection (PJI) is a challenging complication of any arthroplasty procedure. We reviewed our use of static antibiotic-loaded cement spacers (ABLCSs) for staged management of PJI where segmental bone loss, ligamentous instability, or soft-tissue defects necessitate a static construct. We reviewed factors contributing to their failure and techniques to avoid these complications when using ABLCSs in this context.

Aims

Fungal periprosthetic joint infections (PJIs) are rare, but their diagnosis and treatment are highly challenging. The purpose of this study was to investigate the clinical outcomes of patients with fungal PJIs treated with two-stage exchange knee arthroplasty combined with prolonged antifungal therapy.

Aims

The aims of this study were: 1) to describe extended restricted kinematic alignment (E-rKA), a novel alignment strategy during robotic-assisted total knee arthroplasty (RA-TKA); 2) to compare residual medial compartment tightness following virtual surgical planning during RA-TKA using mechanical alignment (MA) and E-rKA, in the same set of osteoarthritic varus knees; 3) to assess the requirement of soft-tissue releases during RA-TKA using E-rKA; and 4) to compare the accuracy of surgical plan execution between knees managed with adjustments in component positioning alone, and those which require additional soft-tissue releases.

Aims. The aim of this study was to assess the effect of posterior cruciate ligament (PCL) resection on flexion-extension gaps, mediolateral soft-tissue laxity, fixed flexion deformity (FFD), and limb alignment during posterior-stabilized (PS) total knee arthroplasty (TKA). Patients and Methods. This prospective study included 110 patients with symptomatic osteoarthritis of the knee undergoing primary robot-assisted PS TKA. All operations were performed by a single surgeon using a standard medial parapatellar approach. Optical motion capture technology with fixed femoral and tibial registration pins was used to assess gaps before and after PCL resection in extension and 90° knee flexion. Measurements were made after excision of the anterior cruciate ligament and prior to bone resection. There were 54 men (49.1%) and 56 women (50.9%) with a mean age of 68 years (. sd. 6.2) at the time of surgery. The mean preoperative hip-knee-ankle deformity was 4.1° varus (. sd. 3.4). Results. PCL resection increased the mean flexion gap significantly more than the extension gap in the medial (2.4 mm (. sd. 1.5) vs 1.3 mm (. sd. 1.0); p < 0.001) and lateral (3.3 mm (. sd. 1.6) vs 1.2 mm (. sd. 0.9); p < 0.01) compartments. The mean gap differences after PCL resection created significant mediolateral laxity in flexion (gap difference: 1.1 mm (. sd. 2.5); p < 0.001) but not in extension (gap difference: 0.1 mm (. sd. 2.1); p = 0.51). PCL resection significantly improved the mean FFD (6.3° (. sd. 4.4) preoperatively vs 3.1° (. sd. 1.5) postoperatively; p < 0.001). There was a strong positive correlation between the preoperative FFD and change in FFD following PCL resection (Pearson’s correlation coefficient = 0.81; p < 0.001). PCL resection did not significantly affect limb alignment (mean change in alignment: 0.2° valgus (. sd. 1.2); p = 0.60). Conclusion. PCL resection creates flexion-extension mismatch by increasing the flexion gap more than the extension gap. The increase in the lateral flexion gap is greater than the increase in the medial flexion gap, which creates mediolateral laxity in flexion. Improvements in FFD following PCL resection are dependent on the degree of deformity before PCL resection. Cite this article: Bone Joint J 2019;101-B:1230–1237

Aims

This study aimed to investigate the relationship between changes in patellar height and clinical outcomes at a mean follow-up of 7.7 years (5 to 10) after fixed-bearing posterior-stabilized total knee arthroplasty (PS-TKA).

Aims

Outcomes of current operative treatments for arthrofibrosis after total knee arthroplasty (TKA) are not consistently positive or predictable. Pharmacological in vivo studies have focused mostly on prevention of arthrofibrosis. This study used a rabbit model to evaluate intra-articular (IA) effects of celecoxib in treating contracted knees alone, or in combination with capsular release.

Objectives. The purpose of this study was to examine the effect of posterior cruciate ligament (PCL) retention, PCL recession, and PCL excision during cruciate-retaining total knee replacement. Methods. A total of 3018 anatomic graduated component total knee replacements were examined; 1846 of these retained the PCL, 455 PCLs were partially recessed, and in 717 the PCL was completely excised from the back of the tibia. Results. Clinical scores between PCL groups favored excision for flexion (p < 0.0001), and recession and retention for stairs (p < 0.0001). There was a mild difference in long-term all-cause aseptic survivorship between PCL-retained (96.4% at 15 years) combined with PCL-recessed groups (96.6% at 15 years) when compared with the PCL-excised group (95.0% at 15 years) (p = 0.0411, Wilcoxon; p = 0.0042, log-rank), as well as tibial or femoral loosening, which reported prosthesis survival of 97.8% at 15 years for PCL-retained knees, 98.2% for recessed knees, and 96.4% for excised knees (p = 0.0934, Wilcoxon; p = 0.0202, log-rank). Conclusions. Despite some trade-off in clinical performance, if the PCL is detached at the time of operation, conversion to a posterior-stabilised prosthesis may not be necessarily required as long as stability in the anteroposterior and coronal planes is achieved

The aim of this study was to analyse the gait pattern, muscle force and functional outcome of patients who had undergone replacement of the proximal tibia for tumour and alloplastic reconstruction of the extensor mechanism using the patellar-loop technique. Between February 1998 and December 2009, we carried out wide local excision of a primary sarcoma of the proximal tibia, proximal tibial replacement and reconstruction of the extensor mechanism using the patellar-loop technique in 18 patients. Of these, nine were available for evaluation after a mean of 11.6 years (0.5 to 21.6). The strength of the knee extensors was measured using an Isobex machine and gait analysis was undertaken in our gait assessment laboratory. Functional outcome was assessed using the American Knee Society (AKS) and Musculoskeletal Tumor Society (MSTS) scores. The gait pattern of the patients differed in ground contact time, flexion heel strike, maximal flexion loading response and total sagittal plane excursion. The mean maximum active flexion was 91° (30° to 110°). The overall mean extensor lag was 1° (0° to 5°). The mean extensor muscle strength was 25.8% (8.3% to 90.3%) of that in the non-operated leg (p < 0.001). The mean functional scores were 68.7% (43.4% to 83.3%) (MSTS) and 71.1 (30 to 90) (AKS functional score). In summary, the results show that reconstruction of the extensor mechanism using this technique gives good biomechanical and functional results. The patients’ gait pattern is close to normal, except for a somewhat stiff knee gait pattern. The strength of the extensor mechanism is reduced, but sufficient for walking. . Cite this article: Bone Joint J 2015;97-B:1063–9

Aims

Periprosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA). Two-stage revision has traditionally been considered the gold standard of treatment for established infection, but increasing evidence is emerging in support of one-stage exchange for selected patients. The objective of this study was to determine the outcomes of single-stage revision TKA for PJI, with mid-term follow-up.

We present a series of four patients with what we have termed the snapping pes syndrome. This is a painful clicking and catching experienced at the posteromedial corner of the knee when moving from flexion to extension. Clinical examination and real time ultrasound are the most useful diagnostic tools. If medical treatment is unsuccessful surgical excision of both the semitendinous and gracilis tendons is indicated for relief of persistent symptoms

Aims

To establish our early clinical results of a new total knee arthroplasty (TKA) tibial component introduced in 2013 and compare it to other designs in use at our hospital during the same period.

Aims

Stiffness is a common complication after total knee arthroplasty (TKA). Pathogenesis is not understood, treatment options are limited, and diagnosis is challenging. The aim of this study was to investigate if MRI can be used to visualize intra-articular scarring in patients with stiff, painful knee arthroplasties.

Aims

The objectives of this study were to assess the effect of anterior cruciate ligament (ACL) resection on flexion-extension gaps, mediolateral soft tissue laxity, maximum knee extension, and limb alignment during primary total knee arthroplasty (TKA).

Aims

The integrity of the soft tissue envelope is crucial for successful treatment of infected total knee arthroplasty (TKA). The purpose of this study was to evaluate the rate of limb salvage, infection control, and clinical function following microvascular free flap coverage for salvage of the infected TKA.

Aims

Aseptic loosening of the tibial component is a frequent cause of failure in primary total knee arthroplasty (TKA). Management options include an isolated tibial revision or full component revision. A full component revision is frequently selected by surgeons unfamiliar with the existing implant or who simply wish to “start again”. This option adds morbidity compared with an isolated tibial revision. While isolated tibial revision has a lower morbidity, it is technically more challenging due to difficulties with exposure and maintaining prosthetic stability. This study was designed to compare these two reconstructive options.

Aims

This study aims to determine the proportion of patients with end-stage knee osteoarthritis (OA) possibly suitable for partial (PKA) or combined partial knee arthroplasty (CPKA) according to patterns of full-thickness cartilage loss and anterior cruciate ligament (ACL) status.

We report a patient who developed an aortic pseudoaneurysm in the L3–L4 disc space after lumbar disc surgery. The diagnosis was made by MRI and aortography, and repair using a prosthetic graft and anterior fusion was successful. We discuss the predisposing factors, the clinical picture and management of vascular injuries during disc excision

The final results up to 15 years are reported of clinical trials of the management of tuberculosis of the spine in Korea and Hong Kong. In Korea, 350 patients with active spinal tuberculosis were randomised to ambulatory chemotherapy or bed rest in hospital (in Masan) or a plaster-of-Paris jacket for nine months (in Pusan). Patients in both centres were also randomised to either PAS plus isoniazid for 18 months or to the same drugs plus streptomycin for the first three months. In Hong Kong, all 150 patients were treated with the three-drug regime and randomised to either radical excision of the spinal lesion with bone graft or open debridement. On average, the disease was more extensive in Korea, but at 15 years (or 13 or 14 years in a proportion of the patients in Korea) the great majority of patients in both countries achieved a favourable status, no evidence of CNS involvement, no radiological evidence of disease, no sinus or clinically evident abscess, and no restriction of normal physical activity. Most patients had already achieved a favourable status much earlier. The earlier results of these trials are confirmed by the long-term follow-up with no late relapse or late-onset paraplegia. The results of chemotherapy on an outpatient basis were not improved by bed rest or a plaster jacket and the only advantage of the radical operation was less late deformity compared with debridement. A second series of studies has shown that short-course regimes based on isoniazid and rifampicin are as effective as the 18-month regimes: ambulatory chemotherapy with these regimes should now be the main management of uncomplicated spinal tuberculosis

Aims

The primary aim of this study was to compare the knee-specific functional outcome of patellofemoral arthroplasty with total knee arthroplasty (TKA) in the management of patients with patellofemoral osteoarthritis.

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.

Aims

The aim of this study was to compare the outcome of revision total knee arthroplasty (TKA) with and without proximalisation of the tibial tubercle in patients with a failed primary TKA who have pseudo patella baja.

Fractures around total knee arthroplasties pose a significant surgical challenge. Most can be managed with osteosynthesis and salvage of the replacement. The techniques of fixation of these fractures and revision surgery have evolved and so has the assessment of outcome. This specialty update summarises the current evidence for the classification, methods of fixation, revision surgery and outcomes of the management of periprosthetic fractures associated with total knee arthroplasty.

Cite this article: Bone Joint J 2016;98-B:1489–96.

Aims

The aim of this to study was to compare the previously unreported long-term survival outcome of the Oxford medial unicompartmental knee arthroplasty (UKA) performed by trainee surgeons and consultants.

Aims

Risk of revision following total knee arthroplasty (TKA) is higher in patients under 55 years, but little data are reported regarding non-revision outcomes. This study aims to identify predictors of dissatisfaction in these patients.

The anatomy and microstructure of the menisci allow the effective distribution of load across the knee. Meniscectomy alters the biomechanical environment and is a potent risk factor for osteoarthritis. Despite a trend towards meniscus-preserving surgery, many tears are irreparable, and many repairs fail.

Meniscal allograft transplantation has principally been carried out for pain in patients who have had a meniscectomy. Numerous case series have reported a significant improvement in patient-reported outcomes after surgery, but randomised controlled trials have not been undertaken.

It is scientifically plausible that meniscal allograft transplantation is protective of cartilage, but this has not been established clinically to date.

Cite this article: Bone Joint J 2015; 97-B:590–4.

Objectives

Subtotal or total meniscectomy in the medial or lateral compartment of the knee results in a high risk of future osteoarthritis. Meniscal allograft transplantation has been performed for over thirty years with the scientifically plausible hypothesis that it functions in a similar way to a native meniscus. It is thought that a meniscal allograft transplant has a chondroprotective effect, reducing symptoms and the long-term risk of osteoarthritis. However, this hypothesis has never been tested in a high-quality study on human participants. This study aims to address this shortfall by performing a pilot randomised controlled trial within the context of a comprehensive cohort study design.

The aim of this study was to compare the maximum laxity conferred by the cruciate-retaining (CR) and posterior-stabilised (PS) Triathlon single-radius total knee arthroplasty (TKA) for anterior drawer, varus–valgus opening and rotation in eight cadaver knees through a defined arc of flexion (0º to 110º). The null hypothesis was that the limits of laxity of CR- and PS-TKAs are not significantly different.

The investigation was undertaken in eight loaded cadaver knees undergoing subjective stress testing using a measurement rig. Firstly the native knee was tested prior to preparation for CR-TKA and subsequently for PS-TKA implantation. Surgical navigation was used to track maximal displacements/rotations at 0º, 30º, 60º, 90º and 110° of flexion. Mixed-effects modelling was used to define the behaviour of the TKAs.

The laxity measured for the CR- and PS-TKAs revealed no statistically significant differences over the studied flexion arc for the two versions of TKA. Compared with the native knee both TKAs exhibited slightly increased anterior drawer and decreased varus-valgus and internal-external roational laxities. We believe further study is required to define the clinical states for which the additional constraint offered by a PS-TKA implant may be beneficial.

Cite this article: Bone Joint J 2015; 97-B:642–8.

We have investigated iatrogenic popliteal artery injuries (PAI) during non arthroplasty knee surgery regarding mechanism of injury, treatment and outcomes, and to identify successful strategies when injury occurs.

In all, 21 iatrogenic popliteal artery injuries in 21 patients during knee surgery other than knee arthroplasty were identified from the Swedish Vascular Registry (Swedvasc) between 1987 and 2011. Prospective registry data were supplemented with case-records, including long-term follow-up. In total, 13 patients suffered PAI during elective surgery and eight during urgent surgery such as fracture fixation or tumour resection. Nine injuries were detected intra-operatively, five within 12 to 48 hours and seven > 48 hours post-operatively (two days to 23 years).

There were 19 open vascular and two endovascular surgical repairs. Two patients died within six months of surgery. One patient required amputation. Only six patients had a complete recovery of whom had the vascular injury detected at time of injury and repaired by a vascular surgeon. Patients sustaining vascular injury during elective procedures are more likely to litigate (p = 0.029).

We conclude that outcomes are poorer when there is a delay of diagnosis and treatment, and that orthopaedic surgeons should develop strategies to detect PAI early and ensure rapid access to vascular surgical support.

Cite this article: Bone Joint J 2015;97-B:192–6.

There are several methods for evaluating stability of the joint during total knee replacement (TKR). Activities of daily living demand mechanical loading to the knee joint, not only in full extension, but also in mid-flexion. The purpose of this study was to compare the varus-valgus stability throughout flexion in knees treated with either cruciate-retaining or posterior-stabilised TKR, using an intra-operative navigation technique. A total of 34 knees underwent TKR with computer navigation, during which the investigator applied a maximum varus-valgus stress to the knee while steadily moving the leg from full extension to flexion both before and after prosthetic implantation. The femorotibial angle was measured simultaneously by the navigation system at every 10° throughout the range of movement. It was found that posterior-stabilised knees had more varus-valgus laxity than cruciate-retaining knees at all angles examined, and the differences were statistically significant at 10° (p = 0.0093), 20° (p = 0.0098) and 30° of flexion (p = 0.0252).

Cite this article: Bone Joint J 2013;95-B:493–7.

We have previously reported the short-term radiological results of a randomised controlled trial comparing kinematically aligned total knee replacement (TKR) and mechanically aligned TKR, along with early pain and function scores. In this study we report the two-year clinical results from this trial. A total of 88 patients (88 knees) were randomly allocated to undergo either kinematically aligned TKR using patient-specific guides, or mechanically aligned TKR using conventional instruments. They were analysed on an intention-to-treat basis. The patients and the clinical evaluator were blinded to the method of alignment.

At a minimum of two years, all outcomes were better for the kinematically aligned group, as determined by the mean Oxford knee score (40 (15 to 48) versus 33 (13 to 48); p = 0.005), the mean Western Ontario McMaster Universities Arthritis index (WOMAC) (15 (0 to 63) versus 26 (0 to 73); p = 0.005), mean combined Knee Society score (160 (93 to 200) versus 137 (64 to 200); p= 0.005) and mean flexion of 121° (100 to 150) versus 113° (80 to 130) (p = 0.002). The odds ratio of having a pain-free knee at two years with the kinematically aligned technique (Oxford and WOMAC pain scores) was 3.2 (p = 0.020) and 4.9 (p = 0.001), respectively, compared with the mechanically aligned technique. Patients in the kinematically aligned group walked a mean of 50 feet further in hospital prior to discharge compared with the mechanically aligned group (p = 0.044).

In this study, the use of a kinematic alignment technique performed with patient-specific guides provided better pain relief and restored better function and range of movement than the mechanical alignment technique performed with conventional instruments.

Cite this article: Bone Joint J 2014;96-B:907–13.

A total of 187 patients with primary osteoarthritis (OA) of the knee undergoing total knee replacement (TKR) were randomly divided into two groups, one of which underwent synovectomy. The patients and assessors were blinded to the randomisation both before and after surgery. The duration of surgery, hospitalisation period, concealed bleeding, drainage volume, blood transfusion rate and range of movement of the knee at three days after the operation were analysed. Patients were followed up at four weeks and 12 months after their operation, and a visual analogue score (VAS) for pain, Knee Society score (KSS) and a patellar ballottement test were compared between the groups.

The mean amount of concealed bleeding was higher in the synovectomy group compared with the control group (1.24 l (0.08 to 3.28) vs 1.03 l (0.16 to 2.94); p = 0.042), as was the mean drainage volume (0.90 l (0.35 to 1.81) vs 0.81 (0.25 to 1.65); p = 0.030). The mean operating time was also higher in the synovectomy group compared with the controls (1.50 hours (1.34 to 1.75) vs 1.41 hours (1.21 to 1.79); p = 0.006). There were no significant differences in blood transfusion rate (p = 0.882), hospital stay (p = 0.805) or range of movement of the knee (p = 0.413) between the two groups. At four weeks and 12 months post-operatively there were no statistically significant differences in any of the measured parameters. We concluded that synovectomy confers no clinical advantages in TKR for primary OA while subjecting patients to higher levels of bleeding and longer operating times.

Cite this article: Bone Joint J 2013;95-B:1197–200.

We compared inflammation in the knee after total knee replacement (TKR) for primary osteoarthritis between two groups of patients undergoing joint replacement with and without synovectomy. A total of 67 patients who underwent unilateral TKR were randomly divided into group I, TKR without synovectomy, and group II, TKR with synovectomy. Clinical outcomes, serial serum inflammatory markers (including interleukin-6 (IL-6), CRP and ESR) and the difference in temperature of the skin of the knee, compared with the contralateral side, were sequentially evaluated until 26 weeks after surgery.

Pre-operatively, there were no statistically different clinical parameters between groups I and II. At the 26-week follow-up, both groups had a similarly significantly improved American Knee Society clinical score (p < 0.001) and functional score (p < 0.001) with no differences between the groups. Similar changes in serial inflammatory markers were found in both groups, including mean peak levels of IL-6 (189 pg/ml (sd 53.4) versus 201 pg/ml (sd 49.4) for groups I and II, respectively) and CRP (91 mg/L (sd 24.1) versus 88 mg/L (sd 23.4), respectively) on the first post-operative day, returning to pre-operative values at two and six weeks, respectively. The mean peak level of ESR for the respective two groups was 46 mm/hr versus 48 mm/hr at two weeks, which had still not returned to its pre-operative mean value at 26 weeks. The elevation in the skin temperature appeared to mirror the peak elevation of the ESR, with a range of 2.5° C to 4.5° C with some reduction at 26 weeks but still exceeding the pre-operative value.

We concluded that synovectomy at the time of TKR does not provide any benefit to the clinical outcome or shorten the duration of the inflammatory response after surgery.

There is conflicting evidence about the merits of mobile bearings in total knee replacement, partly because most randomised controlled trials (RCTs) have not been adequately powered. We report the results of a multicentre RCT of mobile versus fixed bearings. This was part of the knee arthroplasty trial (KAT), where 539 patients were randomly allocated to mobile or fixed bearings and analysed on an intention-to-treat basis. The primary outcome measure was the Oxford Knee Score (OKS) plus secondary measures including Short Form-12, EuroQol EQ-5D, costs, cost-effectiveness and need for further surgery.

There was no significant difference between the groups pre-operatively: mean OKS was 17.18 (sd 7.60) in the mobile-bearing group and 16.49 (sd 7.40) in the fixed-bearing group. At five years mean OKS was 33.19 (sd 16.68) and 33.65 (sd 9.68), respectively. There was no significant difference between trial groups in OKS at five years (-1.12 (95% confidence interval -2.77 to 0.52) or any of the other outcome measures. Furthermore, there was no significant difference in the proportion of patients with knee-related re-operations or in total costs.

In this appropriately powered RCT, over the first five years after total knee replacement functional outcomes, re-operation rates and healthcare costs appear to be the same irrespective of whether a mobile or fixed bearing is used.

Cite this article: Bone Joint J 2013;95-B:486–92.

Radiological assessment of total and unicompartmental knee replacement remains an essential part of routine care and follow-up. Appreciation of the various measurements that can be identified radiologically is important. It is likely that routine plain radiographs will continue to be used, although there has been a trend towards using newer technologies such as CT, especially in a failing knee, where it provides more detailed information, albeit with a higher radiation exposure.

The purpose of this paper is to outline the radiological parameters used to evaluate knee replacements, describe how these are measured or classified, and review the current literature to determine their efficacy where possible.

We retrospectively reviewed the records of 1150 computer-assisted total knee replacements and analysed the clinical and radiological outcomes of 45 knees that had arthritis with a pre-operative recurvatum deformity. The mean pre-operative hyperextension deformity of 11° (6° to 15°), as measured by navigation at the start of the operation, improved to a mean flexion deformity of 3.1° (0° to 7°) post-operatively. A total of 41 knees (91%) were managed using inserts ≤ 12.5 mm thick, and none had mediolateral laxity > 2 mm from a mechanical axis of 0° at the end of the surgery. At a mean follow-up of 26.4 months (13 to 48) there was significant improvement in the mean Knee Society, Oxford knee and Western Ontario and McMaster Universities Osteoarthritis Index scores compared with the pre-operative values. The mean knee flexion improved from 105° (80° to 125°) pre-operatively to 131° (120° to 145°), and none of the limbs had recurrent recurvatum.

These early results show that total knee replacement using computer navigation and an algorithmic approach for arthritic knees with a recurvatum deformity can give excellent radiological and functional outcomes without recurrent deformity.

The purpose of this study was to report the outcome of ‘isolated’ anterior cruciate ligament (ACL) ruptures treated with anatomical endoscopic reconstruction using hamstring tendon autograft at a mean of 15 years (14.25 to 16.9). A total of 100 consecutive men and 100 consecutive women with ‘isolated’ ACL rupture underwent four-strand hamstring tendon reconstruction with anteromedial portal femoral tunnel drilling and interference screw fixation by a single surgeon. Details were recorded pre-operatively and at one, two, seven and 15 years post-operatively. Outcomes included clinical examination, subjective and objective scoring systems, and radiological assessment. At 15 years only eight of 118 patients (7%) had moderate or severe osteo-arthritic changes (International Knee Documentation Committee Grades C and D), and 79 of 152 patients (52%) still performed very strenuous activities. Overall graft survival at 15 years was 83% (1.1% failure per year). Patients aged < 18 years at the time of surgery and patients with > 2 mm of laxity at one year had a threefold increase in the risk of suffering a rupture of the graft (p = 0.002 and p = 0.001, respectively). There was no increase in laxity of the graft over time.

ACL reconstructive surgery in patients with an ‘isolated’ rupture using this technique shows good results 15 years post-operatively with respect to ligamentous stability, objective and subjective outcomes, and does not appear to cause osteoarthritis.

The role of computer-assisted surgery in maintaining the level of the joint in primary knee joint replacement (TKR) has not been well defined. We undertook a blinded randomised controlled trial comparing joint-line maintenance, functional outcomes, and quality-of-life outcomes between patients undergoing computer-assisted and conventional TKR. A total of 115 patients were randomised (computer-assisted, n = 55; conventional, n = 60).

Two years post-operatively no significant correlation was found between computer-assisted and conventional surgery in terms of maintaining the joint line. Those TKRs where the joint line was depressed post-operatively improved the least in terms of functional scores. No difference was detected in terms of quality-of-life outcomes. Change in joint line was found to be related to change in alignment. Change in alignment significantly affects change in joint line and functional scores.

Delayed rather than early reconstruction of the anterior cruciate ligament is the current recommended treatment for injury to this ligament since it is thought to give a better functional outcome. We randomised 105 consecutive patients with injury associated with chondral lesions no more severe than grades 1 and 2 and/or meniscal tears which only required trimming, to early (< two weeks) or delayed (> four to six weeks) reconstruction of the anterior cruciate ligament using a quadrupled hamstring graft. All operations were performed by a single surgeon and a standard rehabilitation regime was followed in both groups. The outcomes were assessed using the Lysholm score, the Tegner score and measurement of the range of movement. Stability was assessed by clinical tests and measurements taken with the KT-1000 arthrometer, with all testing performed by a blinded uninvolved experienced observer. A total of six patients were lost to follow-up, with 48 patients assigned to the delayed group and 51 to the early group. None was a competitive athlete. The mean interval between injury and the surgery was seven days (2 to 14) in the early group and 32 days (29 to 42) in the delayed group. The mean follow-up was 32 months (26 to 36).

The results did not show a statistically significant difference for the Lysholm score (p = 0.86), Tegner activity score (p = 0.913) or the range of movement (p = 1). Similarly, no distinction could be made for stability testing by clinical examination (p = 0.56) and measurements with the KT-1000 arthrometer (p = 0.93).

Reconstruction of the anterior cruciate ligament gave a similar clinical and functional outcome whether performed early (< two weeks) or late at four to six weeks after injury.

The requirement for release of collateral ligaments to achieve a stable, balanced total knee replacement has been reported to arise in about 50% to 100% of procedures. This wide range reflects a lack of standardised quantitative indicators to determine the necessity for a release. Using recent advances in computerised navigation, we describe two navigational predictors which provide quantitative measures that can be used to identify the need for release. The first was the ability to restore the mechanical axis before any bone resection was performed and the second was the discrepancy in the measured medial and lateral joint spaces after the tibial osteotomy, but before any femoral resection.

These predictors showed a significant association with the need for collateral ligament release (p < 0.001). The first predictor using the knee stress test in extension showed a sensitivity of 100% and a specificity of 98% and the second, the difference between medial and lateral gaps in millimetres, a sensitivity of 83% and a specificity of 95%. The use of the two navigational predictors meant that only ten of the 93 patients required collateral ligament release to achieve a stable, neutral knee.

We describe 119 meniscal allograft transplantations performed concurrently with articular cartilage repair in 115 patients with severe articular cartilage damage. In all, 53 (46.1%) of the patients were over the age of 50 at the time of surgery. The mean follow-up was for 5.8 years (2 months to 12.3 years), with 25 procedures (20.1%) failing at a mean of 4.6 years (2 months to 10.4 years). Of these, 18 progressed to knee replacement at a mean of 5.1 years (1.3 to 10.4). The Kaplan-Meier estimated mean survival time for the whole series was 9.9 years (sd 0.4). Cox’s proportional hazards model was used to assess the effect of covariates on survival, with age at the time of surgery (p = 0.026) and number of previous operations (p = 0.006) found to be significant.

The survival of the transplant was not affected by gender, the severity of cartilage damage, axial alignment, the degree of narrowing of the joint space or medial versus lateral allograft transplantation. Patients experienced significant improvements at all periods of follow-up in subjective outcome measures of pain, activity and function (all p-values < 0.05), with the exception of the seven-year Tegner index score (p = 0.076).

A total of 218 patients with unilateral anterior cruciate ligament deficiency were randomly assigned to one of four groups. In group A an anatomical double bundle anterior cruciate ligament reconstruction was performed; group B were treated by a single bundle using an Endobutton for femoral fixation; in group C by a single bundle using RigidFix cross pins for femoral fixation; and in group D by a single bundle using a bioabsorbable TransFix II screw for femoral fixation. For tibial fixation a bioabsorbable Intrafix interference screw was used for all the groups and the graft was fashioned from the semitendinosus and gracilis tendons in all patients. In all, 18 patients were lost to follow-up. The remaining 200 were subjected to a clinical evaluation, with assessment of the anterior drawer, Lachman’s and the pivot-shift tests, and KT-1000 arthrometer measurement. They also completed the International Knee Documentation Committee, Lysholm knee and Tegner activity scores.

At a mean of 29 months (25 to 38) follow-up there were no significant differences concerning time between injury and range of movement and Lysholm knee scores among the four groups. However, the double bundle method showed significantly better results for the pivot-shift test (p = 0.002). The KT 1000 measurements showed a mean difference between the reconstructed knee and the patients’ normal knee of 1.4 mm in the double bundle group and 2.4 mm in the single bundle group; which was statistically significant. The Lachman and anterior drawer tests also showed superior results for the double bundle method. The International Knee Documentation Committee scale showed no significant difference among the groups (p < 0.001).

On clinical evaluation the double bundle group showed less laxity than the single bundle groups. However, regardless of the technique, all knees were improved by anterior cruciate ligament reconstruction compared with their pre-operative status.

From a search of MRI reports on knees, 20 patients were identified with evidence of early anteromedial osteoarthritis without any erosion of bone and a control group of patients had an acute rupture of the anterior cruciate ligament. The angle formed between the extension and flexion facets of the tibia, which is known as the extension facet angle, was measured on a sagittal image at the middle of the medial femoral condyle.

The mean extension facet angle in the control group was 14° (3° to 25°) and was unrelated to age (Spearman’s rank coefficient, p = 0.30, r = 0.13). The mean extension facet angle in individuals with MRI evidence of early anteromedial osteoarthritis was 19° (13° to 26°, SD 4°). This difference was significant (Mann-Whitney U test, p < 0.001).

A wide variation in the extension facet angle was found in the normal control knees and an association between an increased extension facet angle and MRI evidence of early anteromedial osteoarthritis. Although a causal link has not been demonstrated, we postulate that a steeper extension facet angle might increase the duration of loading on the extension facet during the stance phase of gait, and that this might initiate failure of the articular cartilage.

There is little evidence examining the relationship between anatomical landmarks, radiological placement of the tunnels and long-term clinical outcomes following anterior cruciate ligament (ACL) reconstruction. The aim of this study was to investigate the reproducibility of intra-operative landmarks for placement of the tunnels in single-bundle reconstruction of the ACL using four-strand hamstring tendon autografts.

Isolated reconstruction of the ACL was performed in 200 patients, who were followed prospectively for seven years with use of the International Knee Documentation Committee forms and radiographs. Taking 0% as the anterior and 100% as the posterior extent, the femoral tunnel was a mean of 86% (sd 5) along Blumensaat’s line and the tibial tunnel was 48% (sd 5) along the tibial plateau. Taking 0% as the medial and 100% as the lateral extent, the tibial tunnel was 46% (sd 3) across the tibial plateau and the mean inclination of the graft in the coronal plane was 19° (sd 5.5).

The use of intra-operative landmarks resulted in reproducible placement of the tunnels and an excellent clinical outcome seven years after operation. Vertical inclination was associated with increased rotational instability and degenerative radiological changes, while rupture of the graft was associated with posterior placement of the tibial tunnel. If the osseous tunnels are correctly placed, single-bundle reconstruction of the ACL adequately controls both anteroposterior and rotational instability.

Genu varum in the achondroplastic patient has a complex and multifactorial aetiology. There is little mention in the literature of the role of fibular overgrowth. Using the ratio of fibular to tibial length as a measurement of possible fibular overgrowth, we have related it to the development of genu varum. Full-length standing anteroposterior radiographs of 53 patients with achondroplasia were analysed. There were 30 skeletally-immature and 23 skeletally-mature patients. Regression analysis was performed in order to determine if there was a causal relationship between fibular overgrowth and the various indices of alignment of the lower limb.

Analysis showed that the fibular to tibial length ratio had a significant correlation with the medial proximal tibial angle and the mechanical axial deviation in the skeletally-immature group. We conclude that there is a significant relationship between fibular overgrowth and the development of genu varum in the skeletally-immature achondroplastic patient.

We evaluated the long-term fixation of 64 press-fit cemented stems of constrained total knee prostheses in 32 young patients with primary malignant bone tumours. Initial stable fixation, especially in rotation, was achieved by precise fit of the stem into the reamed endosteum, before cementation. Complementary fixation, especially in migration and rotation, was obtained by pressurised antibiotic-loaded cement. The mean age at operation was 33 years (13 to 61). No patient was lost to follow-up; 13 patients died and the 19 survivors were examined at a mean follow-up of 12.5 years (4 to 21). Standard revision press-fit cemented stems were used on the side of the joint which was not involved with tumour (26 tibial and six femoral), on this side there was no loosening or osteolysis and stem survival was 100%. On the reconstruction side, custom-made press-fit stems were used and the survival rate, with any cause for revision as an end point, was 88%, but 97% for loosening or osteolysis. This longevity is similar to that achieved at 20 years with the Charnley-Kerboull primary total hip replacement with press-fit cemented femoral components.

We recommend this type of fixation when extensive reconstruction of the knee is required. It may also be suitable for older patients requiring revision of a total knee replacement or in difficult situations such as severe deformity and complex articular fractures.