Karola Messner

Anterior Cruciate Ligament Reconstruction and the Long Term Incidence of Gonarthrosis

Knee ligament injuries are common in sport. A rupture of the anterior cruciate ligament (ACL) is the most serious of these injuries because it may cause long term disability. In this literature review, the frequency of post-traumatic gonarthrosis is examined. There are few long term prospective studies but a number of retrospective studies with follow-up times between 5 and 20 years have been published. These studies show that radiographic gonarthrosis is significantly increased after all knee injuries compared with the uninjured joint of the same patient. Isolated meniscus rupture and subsequent repair, or partial or total ruptures of the ACL without major concomitant injuries, seem to increase the risk 10-fold (15 to 20% incidence of gonarthrosis) compared with an age-matched, uninjured population (1 to 2%). Meniscectomy in a joint with intact ligaments further doubles the risk of gonarthrosis (30 to 40%), and 50 to 70% of patients with complete ACL rupture and associated injuries have radiographic changes after 15 to 20 years. Thus, an ACL rupture combined with meniscus rupture or other knee ligament injuries results in gonarthrosis in most patients.Ten to 20 years after ACL injury, gonarthrosis often presents as a slight joint space reduction or, occasionally, joint space obliteration (Ahlbäck grades I to II), but is usually not associated with major clinical symptoms. According to the few longitudinal studies, the progress of gonarthrosis is slow, and in some cases the condition seems to remain stable. Time is an important determinant for the degree of gonarthrosis and problems demanding treatment may be encountered only at >30 years after the initial accident.

The long-term prognosis for severe damage to weight-bearing cartilage in the knee: a 14-year clinical and radiographic follow-up in 28 young athletes.

We examined 28 young athletes with isolated severe chondral damage in the weight-bearing area of the knee joint clinically and radiographically 14 years after arthroscopic diagnosis. Except for Pridie drilling in 3 cases and occasional cartilage shaving or removal of free bodies, no special treatment was given initially. 21 patients were able to return to preinjury team sport activity levels. During the follow-up period, only 3 patients needed repeat surgery with removal of free bodies, and another 2 underwent diagnostic arthroscopy because of persistent pain. At the latest follow-up evaluation, 22 patients had excellent or good knee function. At this time, the patients were mainly involved in individual sports on a physical fitness level. 12 cases had radiographic joint space reduction (< 50%) which was limited to the compartment concerned.

The menisci of the knee joint. Anatomical and functional characteristics, and a rationale for clinical treatment.

The menisci and their insertions into bone (entheses) represent a functional unit. Thanks to their firm entheses, the menisci are able to distribute loads and therefore reduce the stresses on the tibia, a function which is regarded essential for cartilage protection and prevention of osteoarthrosis. The tissue of the hypocellular meniscal body consists mainly of water and a dense elaborate type I collagen network with a predominantly circumferential alignment. The content of different collagens, proteoglycans and nonproteoglycan proteins shows significant regional variations probably reflecting functional adaptation. The meniscal horns are attached via meniscal insertional ligaments mainly to tibial bone. At the enthesis, the fibres of the insertional ligaments attach to bone via uncalcified and calcified fibrocartilages. This anatomical configuration of gradual transition from soft to hard tissue, which is identical to other ligament entheses, is certainly essential for normal mechanical function and probably protects this vulnerable transition between 2 biomechanically different tissues from failure. Clinical treatment of meniscal tears needs to be based on these special anatomical and functional characteristics. Partial meniscectomy will preserve some of the load distribution function of the meniscus only when the meniscal body enthesis entity is preserved. Repair of peripheral longitudinal tears will heal and probably preserve the load distribution function of the meniscus, whereas radial tears through the whole meniscal periphery or more central and complex tears may be induced to heal, but probably do not preserve the load distribution function. There is no proof that replacement of the meniscus with an allograft can reestablish some of the important meniscal functions, and thereby prevent or reduce the development of osteoarthrosis which is common after meniscectomy. After implantation, major problems are the remodelling of the graft to inferior structural, biochemical and mechanical properties and its insufficient fixation to bone which fails to duplicate a normal anatomical configuration and therefore a functional meniscal enthesis.

Eighteen- to Twenty-four-Year Follow-up After Complete Rupture of the Anterior Cruciate Ligament:

A unilateral, complete rupture of the anterior cruciate ligament was diagnosed in 60 consecutive patients by arthroscopy within 1 week of trauma. Most ruptured ligaments were treated by acute nonaugmented repair immediately after the arthroscopy. Fifty-five and 56 patients were reevaluated after 12 years and 20 years, respectively. Twenty-five patients (45%) had at least one reoperation during the follow-up period of 20 years, primarily for meniscal problems. Seven patients (13%) had repeat anterior cruciate ligament surgery. The overall Lysholm knee function score remained at a median of 90 points from 12 to 20 years, but patients had decreased their sporting activities from team sports at full rehabilitation to physical fitness activities at the late follow-up. Patients who had repeat surgery had a worse knee function score, were less satisfied with their knees, and also had to change activities and change work more often than patients without reoperation. The majority of patients had, at both follow-up periods, unstable knees. At 20 years, weightbearing radiographs showed slight-to-moderate changes equivalent to osteoarthrosis in 84% (47) of patients and a 32% increase in osteoarthrosis since the 12-year evaluation.

The effect of partial meniscectomy on the long-term prognosis of knees with localized, severe chondral damage. A twelve- to fifteen-year followup

We retrospectively matched 42 patients with unilateral chondral damage in the weightbearing zone of one knee compartment according to sex, age, location of chondral damage, and follow-up time. Two groups of 21 patients were formed. One group had chondral damage only. The other group had chondral damage and a meniscal tear treated with partial meniscectomy. After 12 to 15 years, all patients were reexamined. Twenty-nine percent (N = 6) of the patients who had a partial meniscectomy needed repeat meniscal surgery during followup. No patients with isolated chondral damage developed meniscal symptoms, and only three patients underwent minor surgeries (P < 0.02). At the follow-up evaluation, both groups had similar knee function with a mean Lysholm score of 87 points. However, most patients had reduced their sports ac tivities from competitive individual sports before injury to noncompetitive physical fitness exercise at followup. At the roentgenologic examination, patients who had partial meniscectomies had more severe roentgeno logic signs of osteoarthritis than patients who had chondral damage only (P < 0.03). Meniscectomy, va rus knee alignment at the follow-up evaluation (P < 0.04), and age older than 30 years (P < 0.04) at the time of the operation were associated with a higher incidence of osteoarthritis.

Maturation‐dependent repair of untreated osteochondral defects in the rabbit knee joint

Repair of untreated full-thickness cartilage defects in the medial femoral knee condyle was studied in 17 young, 21 adolescent, and 19 adult rabbits. At 6 weeks, the defect was completely filled by tissue regeneration in all young and adolescent animals, but in only few of the adults (p < 0.05). The morphology of all repairs improved from fibrous tissue to hyaline-like cartilage over time (p < 0.05), but at 3 and 6 weeks, the repair tissue in young and adolescent rabbits was more cartilage-like than in the adults (p < 0.05). In addition, bonding of the repair tissue to the adjacent cartilage was better in the young and adolescent than in the adult animals (p < 0.05). At 12 weeks, subchondral bone had formed in some young and adolescent repairs, but in no case in the adults. None of the repairs showed normal cartilage appearance, but formation of hyaline-like cartilage was common at 12 weeks. Irrespective of age or observation time, the repair site showed decreased stiffness and larger strain values compared to adjacent or control cartilage (p < 0.001) with no tendency for improvement over time. Younger animals showed a faster filling of the defect and an earlier specialization of the repair tissue than adult animals, but the mechanical quality of the regenerated tissue remained inferior to normal.

Long-term results of meniscus repair and meniscectomy: a 13-year functional and radiographic follow-up study.

Abstract This study investigated the long-term outcome of common meniscus treatment (meniscectomy, repair). A consecutive series of 30 patients with open meniscus repair were compared retrospectively to 30 patients who had an arthroscopic partial or subtotal meniscectomy. The groups were matched according to sex, age, meniscus lesion, and follow-up time. The patients were aged 13–43 years at the time of operation; all had intact cruciate ligaments, and none had had previous surgery on the knee. Patients were reexamined at a mean of 13 years after the operation. In addition, for a subgroup of 22 matched pairs, data were available from a 7-year follow-up. Four of the repaired menisci did not heal, and another three reruptured during the 13-year follow-up; these menisci were all excised (23%). Meniscal remnant surgery was needed in 6 cases (20%) after initial meniscectomy. At the 13-year follow-up there was no difference between the groups in knee function, subjective complaints, or manual findings. Almost 90% of the patients in both groups had no knee problems during daily activities. At the late follow-up radiographic signs for bone spurs, sclerosis, or flattening of the femoral condyle were found in around half ¶of the cases in each group. Three patients (10%) with initial repair and ¶8 (27%) with meniscectomy had minor joint space reduction, but no patient had more severe radiographic changes. After 7 years (subgroup) joint space reduction was more common after initial meniscectomy than after repair (P < 0.05). After 13 years the incidence and severity of arthrosis did not differ significantly between the two groups, even when only the successful repairs were compared to meniscectomy (P = 0.06).

Rat Model of Achilles Tendon Disorder

Three-month-old male rats were subjected 3 times weekly for 1 h to eccentric exercise of one triceps surae muscle (30 stimulations/min) under general anesthesia in order to induce Achilles tendon disorder corresponding to paratenonitis and tendinosis in man. Net muscle work during the sessions ranged between 0.67 and 4.37 mJ (mean 1.72, SD 0.77). After 9 and 13 sessions, respectively, 2 rats started to show gait alterations during the functional test which was performed 2–3 times weekly. These rats were killed after additional sessions which showed a worsening of the limp. The other trained rats and controls did not limp and were killed after 7–11 weeks. Histologic evaluation of the Achilles tendons from the exercised limb showed in the majority of the cases hypervascularization, increased number of nerve filaments and increased immunoreactivity for substance P and calcitonin gene-related peptide. The tendons from the nonstimulated limb looked normal. The distribution of collagen types I and II appeared normal in the tendon and its insertion to the calcaneus. Inflammation of the epi- and paratenon could be provoked in the rat, but tendon changes corresponding to chronic tendinosis did not develop within 11 weeks with the used training regime. The clinical relevance of this model for chronic tendon disease needs to be evaluated further.

Maturation‐dependent durability of spontaneous cartilage repair in rabbit knee joint

The spontaneous healing of osteochondral defects in the knee joints of immature rabbits within the first 12 weeks after surgery showed a faster filling and earlier tissue specialization than in adult animals. The purpose of the present study was to investigate whether the better short-term quality of spontaneous repairs in immature animals lasted over a period of 48 weeks. A full-thickness osteochondral defect was created on the medial femoral condyle in both knees of 10 young, 10 adolescent, and 10 adult rabbits. Equal numbers of animals were evaluated after 24 and 48 weeks. At both time intervals, bonding to adjacent cartilage and proteoglycan content of the matrix were better in the repairs of young than in adult animals. Repairs in the former had cellularity similar to the adjacent cartilage and were composed of 90% hyaline-like cartilage, which did not decrease with time. In contrast, repairs in older animals formed less hyaline-like cartilage and had a lower cellularity than the adjacent cartilage. However, the surface of the repaired tissue was similarly disrupted in all age groups, and the mechanical properties remained inferior to adjacent or normal cartilage. Repairs in older animals showed signs of degeneration with time. The initial better repair quality in a young, growing animal remained up to 48 weeks when the animal had already reached maturity, indicating that successful initial promotion of cartilage repair may even lead to better results in the long term. However, it has to be pointed out that the morphologically good repairs with hyaline-like cartilage appearance, normal cellularity, and durability of up to 48 weeks were unable to reestablish and maintain a cartilage-like mechanical function.

Regional differences in cell shape and gap junction expression in rat Achilles tendon: relation to fibrocartilage differentiation

Tendon cells have complex shapes, with many cell processes and an intimate association with collagen fibre bundles in their extracellular matrix. Where cells and their processes contact one another, they form gap junctions. In the present study, we have examined the distribution of gap junction components in phenotypically different regions of rat Achilles tendon. This tendon contains a prominent enthesial fibrocartilage at its calcaneal attachment and a sesamoid fibrocartilage where it is pressed against the calcaneus just proximal to the attachment. Studies using DiI staining demonstrated typical stellate cell shape in transverse sections of pure tendon, with cells withdrawing their cell processes and rounding up in the fibrocartilaginous zones. Coincident with change in shape, cells stopped expressing the gap junction proteins connexins 32 and 43, with connexin 43 disappearing earlier in the transition than connexin 32. Thus, there are major differences in the ability of cells to communicate with one another in the phenotypically distinct regions of tendon. Individual fibrocartilage cells must sense alterations in the extracellular matrix by cell/matrix interactions, but can only coordinate their behaviour via indirect cytokine and growth factor signalling. The tendon cells have additional possibilities — in addition to the above, they have the potential to communicate direct cytoplasmic signals via gap junctions. The formation of fibrocartilage in tendons occurs because of the presence of compressive as well as tensile forces. It may be that different systems are used to sense and respond to such forces in fibrous and cartilaginous tissues.