Hip pathology can exacerbate symptoms of low back pathology. In patients with both, it can be difficult to evaluate back symptoms and hip pathology can be missed. From our hip register, we found that 66 of 814 THA patients (8.11%) had also undergone spinal surgery, 92.4% before THA. Among these 66 patients were 15 (24% or 1.84% of the total number) in whom back surgery did not relieve pain. Their pain disappeared after THA. It may be significant that a neurosurgeon performed the spinal surgery in all cases.

We suggest that orthopaedic surgeons examining patients with back pain always look for a Trendelenburg gait, insist on anteroposterior radiographs of the pelvis, routinely examine the hip when examining the low back and, if dual pathology exists, consider doing THA first.

To investigate whether there are different patterns of patellar degeneration, 123 consecutive knee arthroplasties were investigated. Knees on which previous patellar surgery or osteotomies had been done were excluded. Areas of grade-III or more degeneration of the patella and femoral condyle were recorded.

The femur was divided into three condyles and nine areas. The patella was divided into three facets and nine areas. In 74 (60%) of the knees, patellar degeneration was less than grade III. In 49 (40%) knees, patellar degeneration was grade III or more. In these 49 knees, there were 122 lesions in the nine areas of the femur and 77 lesions in the nine areas of the patella. These lesions were analysed to determine the most common areas of degeneration in the femur and patella and to establish whether there was any pattern of degeneration between the patella and femoral lesions.

The highest incidence of degeneration was found in the medial femoral condyle, central and central-medial patella, probably the areas of highest load in the knee. The areas of least degeneration were in the lateral femur and the superior patella, which are probably the lowest weight-bearing areas. Any pattern of patellar degeneration can occur with any pattern of femoral degeneration.

Lateral and central-patellar facet degeneration are well-recognised clinical and radiological entities. In this series, medial patellar facet degeneration was commonly found. Medial patellar facet degeneration is less well recognised and in the literature is referred to only as secondary to lateral release. In this series, patients with lateral releases were excluded.

The medial facet is especially loaded in the flexed knee. A fixed flexion contracture, as is common in medial compartment osteoarthritis, explains the high incidence of medial facet degeneration. Standard patellar skyline views show only the unloaded medial facet. Medial patellar facet degeneration is probably more common than is recognised and may be a cause of unexplained anterior knee pain, especially in the flexed knee.

Various techniques for meniscal suturing have been described: inside-out, outside-in, and all-inside. In some, the knots are intra-articular, while in others they are outside the joints. Suture materials include barbed absorbable pins, meniscal staples, absorbable and non-absorbable monofilament sutures and non-absorbable multifilament sutures. The gold standard, however, is mattress sutures with non-absorbable multifilament sutures and extra-articular knots.

Because some of the newer fixation devices are quite expensive, give inferior fixation and cause complications through breakage and synovitis following absorption of the material, a simple and inexpensive outside-in technique was developed.

With this technique, it is possible to suture the meniscus from the anterior horn to the anterior third of the posterior horn. The only requirements are two no-20 hypodermic needles, 1/0 monofilament nylon and 2/0 multifilament non-absorbable suture. Mattress-type sutures can be placed either superiorly or inferiorly in the meniscus, with the knot extra-articular. For tears in the posterior two thirds of the meniscus, which is inaccessible with this technique, one of the commercially-available all-inside techniques is used.

To stabilise the dislocating patella, one can increase the medial vectors, decrease the lateral vectors, or combine these options.

Oblique strengthening of vastus medialis increases the medial vectors. This muscle is an active secondary constraint for stabilising the patella. Strengthening this muscle is the cornerstone of treatment of patellar instability, but it is often unsuccessful if the medial patello-femoral ligament is deficient. The medial patellofemoral ligament is the primary passive constraint to lateral dislocation of the patella. Reconstruction of this ligament, which tenses in extension, stabilises the patella in most cases, without the danger of secondary late-stage patellofemoral degeneration. However, in high-riding patellae, effective ligament reconstruction may cause an extensor lag. An elevation of more than 3 mm affects the contact pressures by disturbing the unique relationship between patella and trochlea. Because it can lead to late stage patellofemoral degeneration, trochleaplasty is rarely indicated.

Tibial tubercle transfer decreases the lateral vectors and is indicated in cases of severe patella alta, a markedly increased Q-angle and lateral patellar tilt. The tubercle can be transferred distally or medially or internally rotated. The procedure changes the patellofemoral relationship, increasing the load in the medial tibio-femoral compartment and giving rise to the possibility of late-stage degeneration in both the patellofemoral and the tibiofemoral joints. It should not be undertaken lightly and the amount of shift should be conservative. The lateral retinaculum, which becomes lax in extension in right in flexion, provides about 10% of patellar stability to lateral dislocation. Because most patellae dislocate in early flexion, lateral retinacular release is seldom indicated except in the rare cases where the patella dislocates in late flexion.

In severe cases of patellar instability, it might be necessary to combine reconstruction of the medial patello-femoral ligament with tibial tubercle transfer and even with lateral retinacular release.

At present bone scan is the only objective indicator of homeostasis in the bone and adjacent joint. This prospective study of 19 consecutive osteotomies in 17 patients was undertaken to see whether homeostasis is achieved around the knee after high tibial osteotomy for medial compartment osteoarthritis.

All cases underwent preoperative clinical, radiological and bone scan evaluation. Clinical evaluation included an SF12 score. Radiographs included standard anteroposterior, lateral, intercondylar and skyline patellar views, as well as standing views for measuring the mechanical axis and calculating the degree of correction. The three-phase technecium-99 m scan included blood-flow, blood pool uptake and delayed static imaging. As part of the surgical procedure an arthroscopic examination was performed and the degree of degeneration in all three compartments of the knee were noted. An excision wedge osteotomy was performed, aiming to achieve a 3° mechanical valgus alignment. Tension wire fixation allowed immediate mobilisation. One year postoperatively the clinical examination, standing radiographs and bone scans were repeated and the results statistically analysed.

One year postoperatively the mean SF12 score had improved from a preoperative 13.6 to 21.2 and the mean mechanical alignment from 6.3° of varus (3° to 12°) to 2° of valgus (0° to 4°). The significant decrease in isotope uptake in the medial compartment correlated with the clinical improvement and improved alignment. There was a significant reciprocal change from high uptake in the medial compartment preoperatively to high uptake in the lateral compartment one year postoperatively.

Medial compartment homeostasis was achieved one year after tibial osteotomy, but homeostasis was not achieved in the whole joint. Although correction was so conservative that it resulted in a mean of only 2° of mechanical valgus alignment, the area of increased uptake shifted from medial to lateral compartment. It is probable that the preoperative varus alignment led to reduced load-bearing and disuse osteoporosis in the lateral compartment, and that the increased uptake represents metabolic response to greater load. Possibly lateral compartment homeostasis will be restored over time.

This study shows that even a mild realignment improves homeostasis in the medial compartment. With the development of biological resurfacing, the importance of osteotomy may increase.

During knee arthroplasty operations, it appeared that different patterns of patellar degeneration occur. To confirm this, 123 patellae were evaluated in a prospective study. The patellae of patients who had undergone patellar surgery or osteotomy were excluded.

The femur was divided into three condyles and nine areas, and the patella into three facets and nine areas. Areas of grade-III or more degeneration on the patella and femoral condyle were recorded. In 74 knees (60%), the patellar degeneration was less than grade III. In 49 (40 %), the patellar degeneration was grade III or more. In these 49 knees, there were 122 lesions in the nine areas of the femur and 77 lesions in the nine areas of the patella. These lesions were analysed to determine the most common areas of femoral and patellar degeneration. Further analysis was undertaken to determine whether there was any pattern of degeneration between the patellar and femoral lesions.

The medial femoral condyle, central and central-medial patella had the highest incidence of degeneration. These probably represent areas of greatest load-bearing in the knee. The areas with least degeneration were in the lateral femur and the superior patella, probably the lowest load-bearing areas. It was noted that any pattern of patellar degeneration could occur with any pattern of femoral degeneration. Lateral and central patellar facet degeneration is a well-recognised clinical and radiological condition. Medial patellar facet degeneration was a common finding. The medial facet is especially loaded in the flexed knee. A fixed flexion contractor, common in medial compartment osteoarthritis, may partially explain the high incidence of medial facet degeneration in these patients. Medial patellar facet degeneration is not a well-recognised condition and in the literature is generally considered secondary to lateral release. In this series, patients with lateral releases were excluded.

Standard patellar skyline views show only the unloaded medial facet. Medial patellar facet degeneration is probably more common than is clinically recognised, and may account for unexplained anterior knee pain, especially in the flexed knee. In this situation, pain will be aggravated by a lateral retinacular release.