Introduction. The Kaplan Meier estimator is widely used in orthopedics. In situations where another event prevents the occurrence of the event of interest, the Kaplan Meier estimator is not appropriate and a competing risks model has to be applied. We questioned how much bias is introduced by erroneous use of the Kaplan Meier estimator instead of a competing risks model in a hip revision surgery cohort. Methods. In our previously published cohort study, 62 acetabular revisions (58 patients) were performed between January 1979 and March 1986. Twenty to twenty-five years after surgery, no patients were lost to follow-up. Thirteen patients underwent revision surgery. During the 20 to 25 years follow-up, 30 patients (33 acetabular revisions) died of causes unrelated to their hip surgery. Results. In the data set analyzed, the Kaplan Meier method overestimates the probability of implant failure by 6.7%, 13.8%,26.8%,48.6% at 5, 10, 15 and 20 years respectively. Discussion. We have performed two different analyses for a hip revision surgery cohort and discussed the use of a competing risks model. Ignoring competing risks leads to biased estimations of the probability of having future revision surgery. Therefore we recommended the use of a competing risks model whenever there are competing risks present

We reported on the outcome of 84 Charnley low friction arthroplasties performed by one of us (GH), the period 1973 to 1984, in 69 patients, less than fifty-five years old, with osteoarthritis mainly due to congenital hip disease. The patients were followed prospectively; clinically using the Merle D’Aubigné and Postel scoring system, as modified by Charnley and also radiographically. At the time of the latest follow-up, thirty-seven hips had failed (44%). In thirty-two hips, twenty-eight acetabular and thirty femoral components were revised because of aseptic loosening (six of the femoral components were broken). Three hips were infected and converted to resection arthroplasty. In two more hips a periprosthetic femur fracture occurred three and ten years postoperatively and were treated with internal fixation. After a minimum of twenty-two years from the index operation, 37 original acetabular components and 36 original femoral components were in place for an average of 29 years. The probability of survival for both components with failure for any reason as the end point was 0.51 (95% confidence interval, 0.39 to 0.62) at twenty-five years when 35 hips were at risk. These long term results can be used as a benchmark of endurance of current total hip arthroplasties performed in young patients, with OA mainly due to congenital hip disease

The purpose of this study was to analyse the twenty to twenty-five year outcomes of one hundred and ninetyfive cemented, matte finish, HD-2 THRs performed in one hundred and sixty-six patients with osteoarthritis of the hip by two surgeons. The one hundred and ninety-five THRs (one hundred and sixty-six patients) were followed prospectively by clinical assessment using the Harris Hip Score (HHS) and radiographic analysis. One hundred and forty-nine patients (90%) died with their implant still functioning or still had a successful implant at twenty to twenty-five years follow-up. Ten patients (6%) underwent a revision for aseptic loosening of the acetabular (n=2, 1.2%) or femoral (n=4, 2.4%) component, or both (n=4, 2.4%), that was related to wear-induced osteolysis. 7 (4.2%) patients (eight hips) were lost to follow-up. The mean HHS at the latest follow-up (twenty to twenty-five years) was 88±9. Radiographically, twenty-nine (85%) of the acetabular components were well fixed and four (12%) were probably or possibly loose. Two hips (6%) had probable or possible loosening of the femoral component. At twenty five years, the calculated cumulative survival rate (Kaplan-Meier method) revealed excellent results for revisions (83%±6, any cause) and aseptic loosening (86%±6, femoral component, 93%±3, acetabular component). The surviving patients had a good mean follow-up and radiographic fixation, proving the exceptional long-term success of this implant

Purpose: Fresh osteochondral allograft (FOCA) transplantation has been an effective treatment option with promising long-term clinical outcomes for focal post-traumatic or intra-articular lesions in the knee for young, active individuals. The goal of this study was to assess the osteochondral allograft to characterize the histopathologic features of early and late graft failure, as well as prolonged graft survival. Method: We examined histological features of thirtyfive fresh osteochondral allograft specimens retrieved at the time of subsequent graft revision, osteotomies or total knee arthroplasty. Results: The graft survival time in our samples ranged from one to twenty-five years based on their time to reoperation. Histological features of early graft failures were lack of chondrocyte viability, loss of matrix cationic staining, and features of mechanical instability. Histological features of late graft failures were fracture through the graft, active and incomplete remodelling of the graft bone by the host bone, and resorption of the graft tissue by synovial inflammatory activity at graft edges. Histological features associated with long-term allograft survival included viable chondrocytes, functional preservation of matrix, and complete replacement of the graft bone with the host bone. These long-term histological findings correlate clinically with excellent Oxford Knee Scores (mean 17.5) in age-matched cohorts with allograft transplants surviving 20 (mean 20.9) years or longer. Conclusion: Given chondrocyte viability, long-term allograft survival depends on graft stability by rigid fixation of host bone to graft bone. With the stable osseous graft base, the hyaline cartilage portion of the allograft can survive and function for 25 years or more

The management of symptomatic single bundle Anterior Cruciate Ligament (ACL) ruptures is still a surgical dilemma. Preservation of the intact fibres of the ACL bundle is considered to be a possible source of reinnervation of the ACL autograft which reflects on better proprioceptive knee control after major ligament reconstruction. Results of a prospective study of 67 patients who had a double stranded but single bundle Anterior Cruciate Ligament (ACL) reconstruction for partial ACL ruptures are presented. There were 43 males and 24 females in this study with a mean age at the time of injury of twenty-five years (14 – 40). Eight played sport professionally and thirty-four played at a competitive level. A valgus twisting force was the most common mechanism of injury. Mean injury to operation time was 7.5 weeks (2–12). All procedures were done arthroscopically without using tourniquet, but using an arthroscopy pump and irrigation fluid containing adrenaline. The semitendinosis hamstring graft was used in all reconstructions. The mean follow-up period was 3.3 years (2–5.4). There was one major complication, who developed a reflex sympathetic dystrophy following a saphenous nerve neuroma. The Quality of Life (QOL) score was assessed using the Mohtadi index. The mean pre-operative QOL score of 30 (13–50) was improved to 93 (70–100) post-operatively. Fifty patients were able to return to their previous sporting level at a mean duration of 9 months (6–12). Preservation of mechanoreceptors by performing a double stranded, single bundle ACL reconstruction in partial ACL ruptures in high demand patients yields good results and enables early return to high demand sports

Purpose: The purpose of this study was to determine psychometric properties of the Lysholm score and Tegner activity scale as patient-administered outcomes scores for anterior cruciate ligament injuries of the knee. We hypothesized that these two outcomes measures remain valid by today’s standards twenty-five years after they were originally introduced as physician-administered outcomes instruments. Methods: One thousand seven hundred eighty-three (1783) patients were included in this study. There were 749 females and 1034 males. Average age was 37 years (range, 18 to 77). Isolated ACL tears were documented in 593 patients, and 1190 patients had concurrent injuries including meniscus pathology and/or cartilage damage. Patients with multiple ligamentous injuries were excluded. All patients in this study were diagnosed with an ACL tear at arthroscopy. For responsiveness, scores were measured preoperatively and at a minimum of two years postoperatively. For test-retest, scores were measured at a minimum of two years postoperatively and again within four weeks of the original postoperative questionnaire. For criterion validity, patients completed the short form (SF-12. ®. ) of the health related quality-of-life scale and the IKDC score in addition to Lysholm and Tegner instruments. For all other analyses, preoperative Lysholm score or Tegner activity levels were used. Results: There was acceptable test-retest reliability for overall Lysholm score (ICC=0.94 [95% confidence interval=0.88 to 0.96]) and Tegner (ICC=0.82 [95% confidence interval=0.66 to 0.89]). The minimum detectable change for Lysholm was 8.9 and for Tegner was 1.4. The Lysholm score demonstrated acceptable internal consistency (Cronbach’s alpha=0.72). The Lysholm score correlated with IKDC (r=0.78) and the physical function domain of SF-12. ®. (r=0.43). The Tegner scale correlated with physical function domain of SF-12. ®. (r=0.2) and IKDC (r=0.22). Both scores had acceptable floor and ceiling effects, and all hypotheses were significant. The Lysholm score and Tegner scale both had a large overall effect size. There were no differences between isolated and combined ACL injuries. Conclusion: After 25 years of changes in treatment of ACL injuries and postoperative rehabilitation protocols, the Lysholm knee score and Tegner activity scale continue to demonstrate acceptable psychometric parameters. The Lysholm score and Tegner scale both had acceptable test-retest reliability, construct validity, criterion validity, content validity, and responsiveness when patient-administered similar to the physician-administered results when they were originally validated. Our hypothesis was affirmed

Twenty-five years ago, Prof. Peter H. Beighton, our association’s geneticist, presented a paper reminding us that more than 2 000 genetic diseases and disorders have been identified. Many of the conditions are apparently confined to one particular geographical locality or ethnic group. A large proportion of genetic diseases and disorders has skeletal manifestations. The Little People of South Africa (Association of Persons with Restricted Growth) have needed advice about the management of orthopaedic complications such as spinal problems in achondroplasia, axial deviations of the lower limbs, and in particular the possibilities of limb lengthening in disproportionate skeletal dysplasias. From the story of a young achondroplastic woman who suffered from low back pain and was offered an operation by a neurosurgeon, there stemmed a media-driven report on dwarfs in the Land of Legends near Tzaneen, an epidemiological field study on achondroplasia in the Northern Province, and a combined round table consultation between a team of orthopaedic surgeons and a pair of Pedi sangomas. In the village was an index group of three Pedi women and one man who were diagnosed with probable acrome-somelic dysplasia (Grebe), a form of achondrogenesis. The oldest woman and the man were brother and sister, and the two younger women their daughters by spouses of normal stature. While their heads and faces were normal and their spines straight, their dysmorphic features included shortness of stature (mean height 94 cm), disproportionate limb length and ligamentous laxity. The little man’s late father was also a dwarf, as was one of his eight brothers: there were thus six dwarfs in a direct line in three generations. The dwarf man and woman were both sangomas, as their father had been. None of them had low back pain, but they knew how to cure it

Hyaline cartilage and immature nucleus pulposus possess similar macromolecules in their extracellular matrix, and there is no unique molecular marker to distinguish the two tissues. We show that in normal disc (fifteen to twenty-five years old), the GAG to hydroxyproline ratio (proteoglycan to collagen ratio) within the nucleus pulposus is approximately 28:1. However, the GAG to hydroxyproline ratio within hyaline cartilage of the same group is 2.5:1. This information is important in identifying stem cell conversion to a nucleus pulposus cell phenotype rather than a chondrocyte phenotype for tissue engineering of intervertebral disc. Tissue engineering of intervertebral discs (IVDs) using mesenchymal stem cells (MSCs) induced to differentiate into a disc-cell phenotype has been considered as an alternative treatment for disc degeneration. Since there is no unique marker for disc tissue, and because cartilage and immature nucleus pulposus (NP) possess similar macromolecules in their extracellular matrix, it is currently difficult to recognize MSC conversion to a disc cell. In this study, we compare the proteoglycan to collagen ratio in the NP of normal disc to that of the hyaline cartilage of the endplate within the same group of individuals. To distinguish between a normal NP and hyaline cartilage phenotype for tissue engineering of IVDs. Human lumbar spine specimens were harvested from fresh cadavers, aged twelve week to seventy-nine year. Discs and endplates were examined for total collagen using the hydroxyproline assay and glycosaminoglycan (GAG) content using a standard assay. In a mature disc with no degeneration (fifteen to twentyfive years), the GAG to hydroxyproline ratio within the NP is approximately 28:1. However, the ratio within the hyaline cartilage endplate of the same group is 2.5:1. A high proteoglycan to collagen ratio can be used to distinguish NP cells from chondrocytes. The lower NP collagen content is probably responsible for its gelatinous nature rather than the firm texture of hyaline cartilage, and this is essential for normal disc function. This information is crucial in identifying a NP-like phenotype when MSCs are induced to differentiate into a disc cell as opposed to a chondrocyte, for tissue engineering of IVDs