We randomised 62 knees to receive either cemented or cementless versions of the Oxford unicompartmental knee replacement. The implants used in both arms of the study were similar, except that the cementless components were coated with porous titanium and hydroxyapatite. The tibial interfaces were studied with fluoroscopically-aligned radiographs.

At one year there was no difference in clinical outcome between the two groups. Narrow radiolucent lines were seen at the bone-implant interfaces in 75% of cemented tibial components. These were partial in 43%, and complete in 32%. In the cementless implants, partial radiolucencies were seen in 7% and complete radiolucencies in none. These differences are statistically significant (p < 0.0001) and imply satisfactory bone ingrowth into the cementless implants.

Pigmented villonodular synovitis (PVNS) is a rare benign disease of the synovium of joints and tendon sheaths, which may be locally aggressive. We present 18 patients with diffuse-type PVNS of the foot and ankle followed for a mean of 5.1 years (2 to 11.8). There were seven men and 11 women, with a mean age of 42 years (18 to 73). A total of 13 patients underwent open or arthroscopic synovectomy, without post-operative radiotherapy. One had surgery at the referring unit before presentation with residual tibiotalar PVNS. The four patients who were managed non-operatively remain symptomatically controlled and under clinical and radiological surveillance. At final follow-up the mean Musculoskeletal Tumour Society score was 93.8% (95% confidence interval (CI) 85 to 100), the mean Toronto Extremity Salvage Score was 92 (95% CI 82 to 100) and the mean American Academy of Orthopaedic Surgeons foot and ankle score was 89 (95% CI 79 to 100). The lesion in the patient with residual PVNS resolved radiologically without further intervention six years after surgery. Targeted synovectomy without adjuvant radiotherapy can result in excellent outcomes, without recurrence. Asymptomatic patients can be successfully managed non-operatively. This is the first series to report clinical outcome scores for patients with diffuse-type PVNS of the foot and ankle.

Cite this article: Bone Joint J 2013;95-B:384–90.

We have analysed a number of radiological measurements in an attempt to clarify the predisposing factors for degenerative spondylolisthesis of the lumbosacral junction. We identified 57 patients with a slip and a control group of 293 patients without any radiological abnormality apart from age-related changes. The relative thickness of the L5 transverse process, the sacral table angle and the height of the iliac crest were measured and evaluated. The difference in these measurements between men and women was analysed in the control group.

We found that the transverse process of L5 was extremely slender, the sacral table more inclined, and the L5 vertebra was less deeply placed in the pelvis in patients with a slip compared with the control group. The differences in these three parameters were statistically significant.

We believe that the L5 vertebra is predisposed to slip when these factors act together on a rigidly-stabilised sacrum. This occurs more commonly in women, probably as a result of constitutional differences in the development of the male and female spine.

The August 2012 Spine Roundup³⁶⁰ looks at: neural tissue and polymerising bone cement; a new prognostic score for spinal metastases from prostatic tumours; recovery after spinal decompression; spinal tuberculosis; unintended durotomy at spinal surgery; how carrying a load on your head can damage the cervical spine; and how age changes your lumbar spine.

We compared the clinical, radiological and quality-of-life outcomes between hybrid and total pedicle screw instrumentation in patients undergoing surgery for neuromuscular scoliosis. A matched comparison using prospectively collected data was undertaken. A total of 66 patients underwent posterior or anteroposterior correction and fusion with hybrid (n = 33, mean age at surgery 15.8 years (9.10 to 19.6)) or total pedicle screw instrumentation (n = 33, mean age 14.7 years (7.0 to 20.7)) with a minimum follow-up of two years. The major curve pre-operatively was a mean of 87° (sd 29, 25° to 141°) and 81° (sd 18, 47° to 116°) in the hybrid and total pedicle screw groups, respectively (p = 0.29) and at a minimum of two years it was 33° (sd 20; 2° to 87°) and 20° (sd 12; 1° to 55°), respectively (p = 0.0016). The mean correction of the major curve was 59% (41% to 88%) in the hybrid and 75% (43% to 99%) in the total pedicle screw groups at two-year follow-up (p = 0.0011). The mean operating time was 7.45 hours (sd 2.18) and 6.04 hours (sd 1.71) in the hybrid and total pedicle screw groups, respectively (p = 0.001), and the mean intra-operative blood loss was 3760 ml (sd 2790) and 1785 ml (sd 1110), respectively (p = 0.001).

Total pedicle screw instrumentation provided shorter operating times, less blood loss and better correction of the major curve compared with hybrid constructs in patients undergoing surgery for neuromuscular scoliosis.

We investigated patterns of refracture and their risk factors in patients with congenital pseudarthrosis of the tibia after Ilizarov osteosynthesis. We studied 43 cases in 23 patients. Temporal and spatial patterns of refracture and refracture-free survival were analysed in each case. The refracture-free rate of cumulative survival was 47% at five years and did not change thereafter. Refracture occurred at the previous pseudarthrosis in 16 of 19 cases of refracture. The risk of refracture was significantly higher when osteosynthesis was performed below the age of four years, when the tibial cross-sectional area was narrow, and when associated with persistent fibular pseudarthrosis. Refracture occurs frequently after successful osteosynthesis in these patients. Delaying osteosynthesis, maximising the tibial cross-sectional area and stabilising the fibula may reduce the risk of refracture.

Although much has been published on the causes of slipped upper femoral epiphysis and the results of treatment, little attention has been given to the mechanism of the slip. This study presents the results of the analysis of 13 adolescent femora, and the attempts to reproduce the radiological appearances of a typical slip. The mean age of the skeletons was 13 years (11 to 15). It was found that the internal bony architecture in the zone of the growth plate was such that a slip of the epiphysis on the metaphysis (in the normal meaning of the word slip) could not take place, largely relating to the presence of a tubercle of bone projecting down from the epiphysis. The only way that the appearance of a typical slipped upper femoral epiphysis could be reproduced was by rotating the epiphysis posteromedially on the metaphysis. The presence and size of this peg-like tubercle was shown radiologically by CT scanning in one pair of intact adolescent femurs.

We reviewed the records of 107 consecutive patients who had undergone surgery for disruption of the knee extensor mechanism to test whether an association existed between rupture of the quadriceps tendon and the presence of a patellar spur. The available standard pre-operative lateral radiographs were examined to see if a patellar spur was an indicator for rupture of the quadriceps tendon in this group of patients. Of the 107 patients, 12 underwent repair of a ruptured patellar tendon, 59 had an open reduction and internal fixation of a patellar fracture and 36 repair of a ruptured quadriceps tendon. In the 88 available lateral radiographs, patellar spurs were present significantly more commonly (p < 0.0005) in patients operated on for rupture of the quadriceps tendon (79%) than in patients with rupture of the patellar tendon (27%) or fracture of the patella (15%). In patients presenting with failure of the extensor mechanism of the knee in the presence of a patellar spur, rupture of the quadriceps tendon should be considered as a possible diagnosis.

Osteoporosis is common and the health and financial cost of fragility fractures is considerable. The burden of cardiovascular disease has been reduced dramatically by identifying and targeting those most at risk. A similar approach is potentially possible in the context of fragility fractures. The World Health Organization created and endorsed the use of FRAX, a fracture risk assessment tool, which uses selected risk factors to calculate a quantitative, patient-specific, ten-year risk of sustaining a fragility fracture. Treatment can thus be based on this as well as on measured bone mineral density. It may also be used to determine at-risk individuals, who should undergo bone densitometry. FRAX has been incorporated into the national osteoporosis guidelines of countries in the Americas, Europe, the Far East and Australasia. The United Kingdom National Institute for Health and Clinical Excellence also advocates its use in their guidance on the assessment of the risk of fragility fracture, and it may become an important tool to combat the health challenges posed by fragility fractures.

We retrospectively reviewed 101 consecutive patients with 114 femoral tumours treated by massive bone allograft at our institution between 1986 and 2005. There were 49 females and 52 males with a mean age of 20 years (4 to 74). At a median follow-up of 9.3 years (2 to 19.8), 36 reconstructions (31.5%) had failed. The allograft itself failed in 27 reconstructions (24%).

Mechanical complications such as delayed union, fracture and failure of fixation were studied. The most adverse factor on the outcome was the use of intramedullary nails, followed by post-operative chemotherapy, resection length > 17 cm and age > 18 years at the time of intervention. The simultaneous use of a vascularised fibular graft to protect the allograft from mechanical complications improved the outcome, but the use of intramedullary cementing was not as successful.

In order to improve the strength of the reconstruction and to advance the biology of host–graft integration, we suggest avoiding the use of intramedullary nails and titanium plates, but instead using stainless steel plates, as these gave better results. The use of a supplementary vascularised fibular graft should be strongly considered in adult patients with resection > 17 cm and in those who require post-operative chemotherapy.

We evaluated the survival of moulded monoblock and modular tibial components of the AGC total knee replacement in patients with rheumatoid arthritis. Between 1985 and 1995, 751 knees with this diagnosis were replaced at our institution. A total of 256 tibial components were of the moulded design and 495 of the modular design. The mean follow-up of the moulded subgroup was 9.6 years (0.5 to 14.7), and that of the modular group 7.0 years (0.1 to 14.7).

The groups differed significantly from each other in Larsen grade, cementing of components and patellar resurfacing, but no statistically significant difference between the survival of the components was found (Log rank test, p = 0.91). The cumulative success rate of the moulded group was 96.8% (95% confidence interval 93.6% to 98.4%) at five years and 94.4% (95% confidence interval 90.4% to 96.7%) at ten years, and of the modular group 96.2% (95% confidence interval 94% to 97.6%) and 93.6% (95% confidence interval 89.7% to 96%), respectively. Revision was required in 37 total knee replacements, the main causes were infection, pain, loosening of the tibial component and patellar problems. Survival rates for both components were satisfactory.

Objectives

To study the vascularity and bone metabolism of the femoral head/neck following hip resurfacing arthroplasty, and to use these results to compare the posterior and the trochanteric-flip approaches.

Locognosia, the ability to localise touch, is one aspect of tactile spatial discrimination which relies on the integrity of peripheral end-organs as well as the somatosensory representation of the surface of the body in the brain. The test presented here is a standardised assessment which uses a protocol for testing locognosia in the zones of the hand supplied by the median and/or ulnar nerves.

The test-retest reliability and discriminant validity were investigated in 39 patients with injuries to the median or ulnar nerve. Intraclass correlation coefficients were used to calculate the test-retest reliability. Discriminant validity was assessed by comparing the injured with the unaffected hand.

Excellent test-retest reliability was demonstrated for the injuries to the median (intraclass correlation coefficient 0.924, 95% confidence interval 0.848 to 1.00) and the ulnar nerves (intraclass correlation coefficient 0.859, 95% confidence interval 0.693 to 1.00). The magnitude of the difference in scores between affected and unaffected hands showed good discriminant validity. For injuries to the median nerve the mean difference was 11.1 points (1 to 33; sd 7.4), which was statistically significant (p < 0.0001, paired t-test) and for those of the ulnar nerve it was 4.75 points (1 to 13.5; sd 3.16), which was also statistically significant (paired t-test, p < 0.0001).

The locognosia test has excellent test-retest reliability, is a valid test of tactile spatial discrimination and should be included in the evaluation of outcome after injury to peripheral nerves.

Mobile-bearing posterior-stabilised knee replacements have been developed as an alternative to the standard fixed- and mobile-bearing designs. However, little is known about the in vivo kinematics of this new group of implants. We investigated 31 patients who had undergone a total knee replacement with a similar prosthetic design but with three different options: fixed-bearing posterior cruciate ligament-retaining, fixed-bearing posterior-stabilised and mobile-bearing posterior-stabilised. To do this we used a three-dimensional to two-dimensional model registration technique. Both the fixed- and mobile-bearing posterior-stabilised configurations used the same femoral component. We found that fixed-bearing posterior stabilised and mobile-bearing posterior-stabilised knee replacements demonstrated similar kinematic patterns, with consistent femoral roll-back during flexion. Mobile-bearing posterior-stabilised knee replacements demonstrated greater and more natural internal rotation of the tibia during flexion than fixed-bearing posterior-stabilised designs. Such rotation occurred at the interface between the insert and tibial tray for mobile-bearing posterior-stabilised designs. However, for fixed-bearing posterior-stabilised designs, rotation occurred at the proximal surface of the bearing. Posterior cruciate ligament-retaining knee replacements demonstrated paradoxical sliding forward of the femur.

We conclude that mobile-bearing posterior-stabilised knee replacements reproduce internal rotation of the tibia more closely during flexion than fixed-bearing posterior-stabilised designs. Furthermore, mobile-bearing posterior-stabilised knee replacements demonstrate a unidirectional movement which occurs at the upper and lower sides of the mobile insert. The femur moves in an anteroposterior direction on the upper surface of the insert, whereas the movement at the lower surface is pure rotation. Such unidirectional movement may lead to less wear when compared with the multidirectional movement seen in fixed-bearing posterior-stabilised knee replacements, and should be associated with more evenly applied cam-post stresses.

Treatment strategies for osteoarthritis most commonly involve the removal or replacement of damaged joint tissue. Relatively few treatments attempt to arrest, slow down or reverse the disease process. Such options include peri-articular osteotomy around the hip or knee, and treatment of femoro-acetabular impingement, where early intervention may potentially alter the natural history of the disease. A relatively small proportion of patients with osteoarthritis have a clear predisposing factor that is both suitable for modification and who present early enough for intervention to be deemed worthwhile. This paper reviews recent advances in our understanding of the pathology, imaging and progression of early osteoarthritis.

Objectives

This study aims to assess the correlation of CT-based structural rigidity analysis with mechanically determined axial rigidity in normal and metabolically diseased rat bone.

With the development of systems of trauma care the management of pelvic disruption has evolved and has become increasingly refined. The goal is to achieve an anatomical reduction and stable fixation of the fracture. This requires adequate visualisation for reduction of the fracture and the placement of fixation. Despite the advances in surgical approach and technique, the functional outcomes do not always produce the desired result. New methods of percutaneous treatment in conjunction with innovative computer-based imaging have evolved in an attempt to overcome the existing difficulties. This paper presents an overview of the technical aspects of percutaneous surgery of the pelvis and acetabulum.

We treated 108 patients with a pertrochanteric femoral fracture using either the dynamic hip screw or the proximal femoral nail in this prospective, randomised series. We compared walking ability before fracture, intra-operative variables and return to their residence. Patients treated with the proximal femoral nail (n = 42) had regained their pre-operative walking ability significantly (p = 0.04) more often by the four-month review than those treated with the dynamic hip screw (n = 41). Peri-operative or immediate post-operative measures of outcome did not differ between the groups, with the exception of operation time. The dynamic hip screw allowed a significantly greater compression of the fracture during the four-month follow-up, but consolidation of the fracture was comparable between the two groups. Two major losses of reduction were observed in each group, resulting in a total of four revision operations.

Our results suggest that the use of the proximal femoral nail may allow a faster postoperative restoration of walking ability, when compared with the dynamic hip screw.

Objectives

The accuracy and precision of two new methods of model-based radiostereometric analysis (RSA) were hypothesised to be superior to a plain radiograph method in the assessment of polyethylene (PE) wear.