Three hundred and nineteen patients who had chondromalacia patellae and persistent patellofemoral pain after six months of conservative management underwent arthroscopy and arthroscopic surgery. The results in four aetiological groups were reviewed at one year and five years after operation. Morbidity was minimal. Lavage produced early remission in all groups. Shaving offered a particular advantage in the post-traumatic group. Lateral release plus shaving and lavage was beneficial in the group with maltracking patellae and in half of the idiopathic group. In the group with unstable patellae, lateral release produced good results in only one in four patients. In conclusion, we consider that arthroscopic surgery has a useful role to play in the management of chondromalacia patellae

1. It is suggested that abruptness of the condylar ridges on the femur plays a major role in the etiology of chondromalacia patellae. The medial condylar ridge is always abrupt in these cases, and indeed in many knees with no evidence of chondromalacia patellae. The lateral condylar ridge is rarely abrupt. 2. The short-term results of forty operations for reduction of femoral ridges in thirty-eight patients, with preservation of the patella in thirty-two cases, are satisfactory

1. The occurrence of bilateral double-layer patellae in association with multiple epiphysial dysplasia is described in three siblings. 2. Twelve cases of bilateral double-layer patellae have been reported previously, and in all there was an accompanying skeletal dystrophy which, although not diagnosed as such, is likely to have been multiple epiphysial dysplasia. 3. It is suggested that although they occur only in a minority of cases, double-layer patellae when present are a feature of considerable diagnostic value in multiple epiphysial dysplasia. Lateral radiography of the knees may therefore be of assistance in the diagnosis of multiple epiphysial dysplasia

Full thickness samples of articular cartilage were removed from areas of chondromalacia on the medial and "odd" facets of the patellae of 21 adults and examined by histology, autoradiography and electron microscopy. Surface fibrillation, loss of superficial matrix staining and reduced 35SO4 labelling was seen, with little change in the deep zone. Ten cases showed "fibrous metaplasia" of the superficial cartilage with definite evidence of cell division and apparent smoothing of the surface. Scattered chondrocyte replication appeared to occur in the surrounding intact cartilage. The findings suggest that early lesions in chondromalacia patellae may heal either by cartilage or fibrous metaplasia and that this may account for the resolution of clinical symptoms

Six cases of osteochondritis dissecans patellae have been studied in five patients in an attempt to clarify the aetiology and prognosis. Assessment of the results of treatment was performed using a standard protocol. The thirty-four previous case reports in the literature are reviewed. In four of the five patients symptoms began after flexing the knee under load and three showed patellar subluxation on tangential radiographs. Thus, repetitive shearing stress on the patellar surface is thought to be an important aetiological factor. The indication for operation is a loose osteochondral fragment either wholly or partly detached from the articular surface of the patella. Vertical excision of the affected area of articular cartilage with drilling of the underlying bone gave two "good" and two "excellent" results. Healing of the drilled area and maintenance of the cartilage space was seen in radiographs of all four cases so treated. This simple method of treatment, which probably causes filling of the defect in the surface by fibrocartilage, is recommended

Four methods of surgical treatment of chondromalacia patellae have been evaluated after periods ranging from two to thirty years (average seven years), to discover the success rate, complications and indications for each. A total of 140 operations had been performed in 98 patients. Overall, satisfactory results were achieved in 25 per cent after forty shavings of the patellar cartilage, 35 per cent after twenty cartilage excisions and drilling of the subchondral bone, 60 per cent after twenty medial transfers of the patellar tendon and 77 per cent after sixty patellectomies. Thirty-four primary patellectomies gave 82 per cent satisfactory results compared with 62 per cent after twenty-six patellectomies performed after a previously unsuccessful operation. The results were worst in patients below twenty years of age especially women and in those with Grade IV changes in the patellar cartilage. Weakness of the quadriceps after any procedure predisposed to an unsatisfactory result. Extensive late radiological degenerative changes in the knee were not seen. On the basis of the results in this report, patellar tendon transfer is recommended in adolescents and athletes with Grade I, II or III changes in the patellar cartilage. In adults over twenty years of age with Grade I and II changes cartilage excision and drilling is satisfactory. In adults with Grade III and adults or adolescents with Grade IV changes patellectomy is the treatment of choice

1 . Current theories of the etiology of chondromalacia patellae do not explain satisfactorily either its great frequency or its common site of origin on the medial patellar facet. 2. The etiology can be more logically explained by the presence of a ridge on the upper anterior border of the cartilage of the medial femoral condyle, in most knees. This ridge, consisting of cartilage, or cartilage and bone, varies considerably in height and, in normal knee joint movement, causes considerable friction on the medial patellar facet. 3. The degenerative changes were found to be greater in the presence of the larger ridges, and–because of longer wear and tear–in the older patients. 4. This study indicates that chondromalacia was more severe in women than in men, and in patients overweight. Although the activity of the individual and the power of the quadriceps mechanism must play an extremely important part in this condition, it was not possible to assess this. 5. Two factors previously considered to be important in the etiology of this condition, namely, the length of the patellar tendon and Wiberg's Type III patellar shape, have not been confirmed in this study. 6. Resulting from the present investigation certain precautions are suggested in rehabilitation after operations on the knee, and a surgical method for discouraging the progress of this common, and sometimes disabling, condition has been devised

Minor degrees of malalignment of the patella and anatomical abnormalities including a flattened sulcus angle and an increased ratio between patellar tendon length and patellar length (PT:P) have been suggested as predisposing factors in the causation of chondromalacia patellae, as well as patellar instability. In order to confirm or refute this hypothesis a prospective study has been performed comparing the congruence and sulcus angles and the PT:P ratio in a group of 35 patients with chondromalacia confirmed by arthroscopy and a group of 33 patients with instability, with those of a group of 50 knees in normal volunteers. While there was a statistically significant correlation between an increased sulcus and congruence angle and a high-riding patella in patients with instability, no correlation could be identified in patients with idiopathic chondromalacia

A new radiological technique is presented in which serial axial radiographs of the patellofemoral joints are taken under conditions in which the muscles about the knee and hip are contracted in a manner similar to that during weight-bearing. A form of analysis has been developed whereby patellar rotation can be measured in two planes and femoral rotation about its long axis inferred. A population of asymptomatic adults and children was investigated in this way and their results (regarded as normal) compared with those in fifteen children with idiopathic chondromalacia patellae. In the normal child the femur rotates medially with the onset of muscle activity; by contrast the children with chondromalacia show a reversal of this mechanism

Aims

This systematic review and meta-analysis aimed to compare the influence of patellar resurfacing following cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) on the incidence of anterior knee pain, knee-specific patient-reported outcome measures, complication rates, and reoperation rates.

Aims

The use of cementless total knee arthroplasty (TKA) components has increased during the past decade. The initial design of cementless metal-backed patellar components had shown high failure rates due to many factors. The aim of this study was to evaluate the clinical results of a second-generation cementless, metal-backed patellar component of a modern design.

1. Chondromalacia of the patella starts most frequently on the medial facet.

2. The anatomy of the medial femoral condyle is described, including the rim at its superior border, and the different arrangement at the upper border of the lateral femoral condyle.

3. Rubbing of the medial patellar facet on the rim at the upper border of the medial femoral condyle can explain in part the etiology of chondromalacia.

The articular cartilage of the patella was studied in 100 knees at necropsy. In twenty-one of these knees the cartilage changes were related to the trabecular architecture of the underlying bone. It would appear that the initiation and location of cartilage damage and its rate and degree of progression are related to the relative stiffness of the underlying cancellous bone. On the basis of our observations we suggest that the diagnosis "chondromalacia of the patella" should be reserved for patients with asymptomatic or transiently symptomatic fibrillation of the articular cartilage of the central medial patellar facet. Those patients with persistent patellofemoral pain should be considered to have some other syndrome.

Two distinct lesions affect the articular cartilage of the patella. Surface degeneration occurs particularly on the odd facet; it is age dependent, often present in youth and it becomes more frequent with increasing age. It probably does not occasion patello-femoral pain in youth, but may predispose to degenerative arthritis in that joint in later years and is regarded as a consequence of habitual disuse. The term "basal degeneration" is used to describe a lesion in which there is a fasciculation of collagen in the middle and deep zones of cartilage without, at first, affecting the surface. It was found astride the ridge separating the medial from the odd facet in twenty-three adolescents who had complained of prolonged patello-femoral pain. They were treated by excision of the disc of affected cartilage, with relief of pain in most cases. The pathogenesis of basal degeneration is related to the functional anatomy of the patella.

A series of 100 consecutive osteoarthritic patients was randomised to undergo total knee replacement using a Miller-Galante II prosthesis, with or without a cemented polyethylene patellar component. Knee function was evaluated using the American Knee Society score, Western Ontario and McMaster University Osteoarthritis index, specific patellofemoral-related questions and radiographic evaluation until the fourth post-operative year, then via questionnaire until ten years post-operatively. A ten-point difference in the American Knee Society score between the two groups was considered a significant change in knee performance, with α and β levels of 0.05. The mean age of the patients in the resurfaced group was 71 years (53 to 88) and in the non-resurfaced group was 73 years (54 to 86). After ten years 22 patients had died, seven were suffering from dementia, three declined further participation and ten were lost to follow-up. Two patients in the non-resurfaced group subsequently had their patellae resurfaced. In the resurfaced group one patient had an arthroscopic lateral release. There was no significant difference between the two treatment groups: both had a similar deterioration of scores with time, and no further patellofemoral complications were observed in either group. We are unable to recommend routine patellar resurfacing in osteoarthritic patients undergoing total knee replacement on the basis of our findings

The Insall-Salvati method of determining the position of the patella by radiography was employed in fifty-one patients with chondromalacia patellae that had been proved at arthrotomy. There was no definite relationship between chondromalacia patellae and patella alta. There was, however, a highly significant statistical difference between the ratio of the length of the patella to that of the patellar tendon in normal men and women

To measure the patellar height the ratio of the articular length of the patella to the height of the lower pole of the articular cartilage above the tibial plateau is measured on a lateral radiography of the knee, flexed beyond 30 degrees. Normal values lie between 0-54 and 1-06. The subluxing patella is at the upper end of the normal range, but, in chondromalacia, the male patellae were lower than average, but the female patellae were normal