We conducted a randomised prospective study to evaluate the clinical and radiological results of a mobile- and fixed-bearing total knee replacement of similar design in 174 patients who had bilateral simultaneous knee replacement. The mean follow-up was for 5.6 years (5.2 to 6.1).

The total knee score, pain score, functional score and range of movement were not statistically different (p > 0.05) between the two groups. Osteolysis was not seen in any knee in either group. Two knees (1%) in the mobile-bearing group required revision because of infection; none in the fixed-bearing group needed revision. Excellent results can be achieved with both mobile- and fixed-bearing prostheses of similar design at mid-term follow-up. We could demonstrate no significant clinical advantage for a mobile bearing.

We reviewed 13 patients with infected nonunion of the distal femur and bone loss, who had been treated by radical surgical debridement and the application of an Ilizarov external fixator. All had severely restricted movement of the knee and a mean of 3.1 previous operations. The mean length of the bony defect was 8.3 cm and no patient was able to bear weight.

The mean external fixation time was 309.8 days. According to Paley’s grading system, eight patients had an excellent clinical and radiological result and seven excellent and good functional results. Bony union, the ability to bear weight fully, and resolution of the infection were achieved in all the patients. The external fixation time was increased when the definitive treatment started six months or more after the initial trauma, the patient had been subjected to more than four previous operations and the initial operation had been open reduction and internal fixation.

The August 2012 Research Roundup³⁶⁰ looks at: PRP and chondrogenic differentiation; basic fibroblast growth factor; whether glucosamine works; randomised trials; ossification of the ligamentum flavum; treadmill running; inhibiting BMP antagonists; and whether NSAIDs delay union after all.

Seven stiff total knee arthroplasties are presented to illustrate the roles of: 1) manipulation under general anesthesia; 2) multiple concurrent diagnoses in addition to stiffness; 3) extra-articular pathology; 4) pain as part of the stiffness triad (pain and limits to flexion or extension); 5) component internal rotation; 6) multifactorial etiology; and 7) surgical exposure in this challenging clinical problem.

We investigated the extent to which improved balance relative to pain relief correlates with the success of total knee replacement (TKR). A total of 81 patients were recruited to the study: 16 men (19.8%) and 65 women (80.2%). Of these, 62 patients (10 men, 52 women) with a mean age of 73 (57 to 83) underwent static and dynamic assessment of balance pre-operatively and one year post-operatively. The parameters of balance were quantified using commercially available and validated equipment. Motor function and self-reported outcome were also assessed.

There was a significant improvement in dynamic balance (p < 0.001) one year after TKR, and better balance correlated with improved mobility, functional balance and increased health-related quality of life. As it seems that balance, and not only pain relief, influences the success of TKR, balance skills should be better addressed during the post-operative rehabilitation of patients who undergo TKR.

Objectives

We aimed first to summarise minimal clinically important differences (MCIDs) after total hip (THR) or knee replacement (TKR) in health-related quality of life (HRQoL), measured using the Short-Form 36 (SF-36). Secondly, we aimed to improve the precision of MCID estimates by means of meta-analysis.

Patients with skeletal dysplasia are prone to developing advanced osteoarthritis of the knee requiring total knee replacement (TKR) at a younger age than the general population. TKR in this unique group of patients is a technically demanding procedure owing to the deformity, flexion contracture, generalised hypotonia and ligamentous laxity. We retrospectively reviewed the outcome of 11 TKRs performed in eight patients with skeletal dysplasia at our institution using the Stanmore Modular Individualised Lower Extremity System (SMILES) custom-made rotating-hinge TKR. There were three men and five women with mean age of 57 years (41 to 79). Patients were followed clinically and radiologically for a mean of seven years (3 to 11.5). The mean Knee Society clinical and function scores improved from 24 (14 to 36) and 20 (5 to 40) pre-operatively, respectively, to 68 (28 to 80) and 50 (22 to 74), respectively, at final follow-up. Four complications were recorded, including a patellar fracture following a fall, a tibial peri-prosthetic fracture, persistent anterior knee pain, and aseptic loosening of a femoral component requiring revision. Our results demonstrate that custom primary rotating-hinge TKR in patients with skeletal dysplasia is effective at relieving pain, with a satisfactory range of movement and improved function. It compensates for bony deformity and ligament deficiency and reduces the likelihood of corrective osteotomy. Patellofemoral joint complications are frequent and functional outcome is worse than with primary TKR in the general population.

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 low contact stress patellofemoral replacement consists of a trochlear component and a modular patellar component which has a metal-backed mobile polyethylene bearing. We present the early results of the use of this prosthesis for established isolated patellofemoral arthritis in 51 consecutive patellofemoral replacements in 35 patients. The mean follow-up was 25 months (5 to 60). The estimated survival rate at three years was 63% (95% confidence interval 47 to 80) with revision as the endpoint and 46% (95% confidence interval 30 to 63) with revision and ongoing moderate or severe pain as the endpoint.

The early results of the use of the low contact stress patellofemoral replacement are disappointing with a high rate of revision. We cannot therefore recommend its use.

This annotation considers the place of extra-articular reconstruction in the treatment of anterior cruciate ligament (ACL) deficiency. Extra-articular reconstruction has been employed over the last century to address ACL deficiency. However, the technique has not gained favour, primarily due to residual instability and the subsequent development of degenerative changes in the lateral compartment of the knee. Thus intra-articular reconstruction has become the technique of choice. However, intra-articular reconstruction does not restore normal knee kinematics. Some authors have recommended extra-articular reconstruction in conjunction with an intra-articular technique.

The anatomy and biomechanics of the anterolateral structures of the knee remain largely undetermined. Further studies to establish the structure and function of the anterolateral structures may lead to more anatomical extra-articular reconstruction techniques that supplement intra-articular reconstruction. This might reduce residual pivot shift after an intra-articular reconstruction and thus improve the post-operative kinematics of the knee.

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.

We evaluated 535 consecutive primary cementless total knee replacements (TKR). The mean follow-up was 9.2 years (0.3 to 12.9) and information on implant survival was available for all patients. Patients were divided into two groups: 153 obese patients (BMI ≥ 30) and 382 non-obese (BMI < 30). A case-matched study was performed on the clinical and radiological outcome, comparing 50 knees in each group. We found significantly lower mean improvements in the clinical score (p = 0.044) and lower post-operative total clinical scores in the obese group (p = 0.041). There was no difference in the rate of radiological osteolysis or lucent lines, and no difference in alignment. Log rank test for survival showed no significant differences between the groups (p = 0.167), with a ten-year survival rate of 96.4% (95% confidence interval (CI) 92 to 99) in the obese and 98% (95% CI 96 to 99) in the non-obese.

The mid-term survival of TKR in the obese and the non-obese are comparable, but obesity appears to have a negative effect on the clinical outcome. However, good results and high patient satisfaction are still to be expected, and it would seem unreasonable to deny patients a TKR simply on the basis of a BMI indicating obesity.

We report a case of local compression-induced transient femoral nerve palsy in a 46-year-old man. He had previously undergone surgical release of the soft tissues anterior to both hip joints because of contractures following spinal injury. An MRI scan confirmed a synovial cyst originating from the left hip joint, lying adjacent to the femoral nerve. The cyst expanded on standing, causing a transient femoral nerve palsy. The symptoms resolved after excision of the cyst.

Locking after total knee replacement is uncommon and is generally caused by the formation of fibrous tissue around the patella. We report an unusual cause of locking resulting from intermittent occlusion of the popliteal artery, which was tethered to cement at the posterior aspect of the tibial component.

The Unispacer knee system is a cobalt-chrome self-centring tibial hemiarthroplasty device for use in the treatment of isolated medial compartment osteoarthritis of the knee. The indications for use are similar to those for high tibial osteotomy, but insertion does not require bone cuts or component fixation, and does not compromise future knee replacement surgery. A prospective study of a consecutive series of 18 patients treated with the Unispacer between June 2003 and August 2004 was carried out to determine the early clinical results of this device. The mean age of the patients was 49 years (40 to 57). A total of eight patients (44%) required revision within two years. In two patients revision to a larger spacer was required, and in six conversion to either a unicompartmental or total knee replacement was needed. At the most recent review 12 patients (66.7%) had a Unispacer remaining in situ. The mean modified visual analogue score for these patients at a mean follow-up of 19 months (12 to 26) was 3.0 (0 to 11.5). The mean pain level was 30% that of the mean pre-operative level of 10. The early clinical results using this device have been disappointing.

This study demonstrates that use of the Unispacer in isolated medial compartment osteoarthritis is associated with a high rate of revision surgery and provides unpredictable relief of pain.

Pain is the main indication for performing total knee replacement (TKR). In most patients after TKR there is an improvement, but a few continue to have pain. Generally, the cause of the pain can be addressed when it is identified. However, unexplained pain can be more difficult to manage because revision surgery is likely to be unrewarding in this group. In our study of 622 cemented TKRs in 512 patients with a mean age of 69 years (23 to 90) treated between January 1995 and August 1998, we identified 24 patients (knees) with unexplained pain at six months. This group was followed for five years (data was unavailable for 18 knees) and ten patients (55.5%) went on to show an improvement without intervention.

In the case of unexplained pain, management decisions must be carefully considered, but reassurance can be offered to patients that the pain will improve in more than half with time.

The purpose of this study was to determine objectively the outcome of total knee replacement in patients with ankylosed knees.

There were 82 patients (99 knees) with ankylosed knees who underwent total knee replacement with a condylar constrained or a posterior stabilised prosthesis. Their mean age was 41.9 years (23 to 60) and the mean follow-up was for 8.9 years (6.6 to 14). Pre- and post-operative data included the Hospital for Special Surgery (HSS), the Knee Society (KS) and the Western Ontario and McMaster University Osteoarthritis index (WOMAC) scores.

The mean HSS, KS and WOMAC scores improved from 60, 53, and 79 pre-operatively to 81, 85, and 37 at follow-up. These improvements were statistically significant (p = 0.018, 0.001 and 0.014 respectively). The mean physical, social and emotional WOMAC scores also improved significantly (p = 0.032, p = 0.023 and p < 0.001 respectively). The mean satisfaction score was 8.5 (sd 1.5).

Total knee replacement gives good mid-term results in patients with ankylosed knees.