To determine the 1-year self-reported incidence of overuse and traumatic sport injuries and risk factors for injuries in children participating in a summer sports camp representing seven different sports. 4363 children, 11 to 15 years old participating in a summer camp in seven different sports answered a questionnaire. Injury in this cross-sectional study was defined as a sport-related trauma or overload leading to pain and dysfunction preventing the person from participation in training or competition for at least 1 week. A number of risk factors for injury were investigated such as sex, age, number of hours spent on training in general, and on resistance training with weights. Nearly half [49%, 95% confidence interval (CI) 48–51%] of the participants had been injured as a result of participation in a sport during the preceding year, significantly more boys than girls (53%, 95% CI 50–55% vs 46%, 95% CI 43–48%; P < 0.001). Three factors contributed to increased incidence of sport injuries: age, sex, and resistance training with weights. Time spent on resistance training with weights was significantly associated with sport injuries in a logistic regression analysis. In children age 11 to 15 years, the risk of having a sport-related injury increased with age and occurred more often in boys than in girls. Weight training was the only modifiable risk factor that contributed to a significant increase in the incidence of sport injuries.

Purpose: The purpose of this study was to compare the clinical and radiographic outcome of arthroscopic partial and total meniscectomy.

Type of Study: Retrospective outcome study.

Methods: Thirty-six male patients with stable knees, no previous knee injury, and arthroscopic meniscectomy were matched into 2 groups: partial or total. In addition, a group of individuals with no known history of knee injury was matched to each patient with meniscectomy. All patients were re-examined by a clinical and radiographic examination 14 years after surgery.

Results: At follow-up, radiographic changes, including Fairbank changes and joint space narrowing, were seen in 6 of 18 patients (33%) after partial meniscectomy and in 13 of 18 patients (72%) after total meniscectomy (P < .05). Joint space narrowing >50% of the joint space was seen in 1 patient after partial meniscectomy but was present in 7 patients after total meniscectomy. In the healthy controls, 4 of 36 patients (11%) had radiographic changes but none had joint space narrowing. Fourteen years after surgery almost 70% of patients had a Lysholm score >94 (i.e., normal). Only 5 of 36 patients (14%) in the total meniscectomy group had knee symptoms during activities of daily living. A similar decline in activity levels according to Tegner was seen over time in the control group and in the 2 meniscectomy groups. Conclusions: The frequency of radiographic changes 14 years after meniscectomy is related to the size of the meniscus removed, but the grades of these changes are low and have little influence on activity and knee function.

Increasing knowledge about the function of the meniscus and arthroscopy have made meniscus surgery more conservative. Arthroscopy was developed during the 70's and enabled the surgeon to select the most appropriate and tissue conserving therapy for a meniscus lesion. Arthroscopic meniscectomy and meniscus repair were introduced as new techniques for treatment of meniscus lesions.

This thesis comprises five long term follow-up studies of arthroscopic meniscectomy and open meniscus repair and one short term follow-up study of arthroscopic meniscectomy.

The long term follow-up studies include 152 patients, 113 with meniscectomy and 39 with meniscus repair, with stable knees, age less than 44 years and without preexisting gonarthrosis. All patients had a diagnostic at1hroscopy at the index operation and were evaluated clinically and radiographically 13-14 years after surgery.

At follow-up the frequency of radiographic changes was high but in general the radiographic changes were of a low grade. Only seven patients, 4 of 86 (5%) after partial meniscectomy and 3 of 27. (11%) after total meniscectomy fulfilled the criteria for gonarthrosis (minimal joint space less than 3 mm on radiographs and symptoms). More radiographic changes were found after total meniscectomy than after partial meniscectomy, meniscus repair or than in an un-injured control group. A similar rate of radiographic changes was seen when meniscus repair was compared to matched patients with partial and total meniscectomy. Knee function was in general good at follow-up and did not differ between patients with total meniscectomy and partial meniscectomy but patients with meniscus repair had a somewhat better knee function than a group of patients with partial and total meniscectomy. Cartilage fibril1ation present at meniscectomy did not influence the frequency of radiographic changes, knee function or activity at follow-up but older patients had more radiographic changes after meniscectomy than younger patients. The activity level decreased in a similar fashion over time after total meniscectomy, partial meniscectomy, meniscus repair and in un-injured subjects indicating that factors other than the knee injury and meniscus operation determines the decline in activity.

Thus, irrespective of meniscus treatment (arthroscopic partial/total meniscectomy and meniscus repair), in a 13-14 year perspective, the grade of radiographic changes in the knee joint were relatively low with no influence on activity and little influence on knee function.

In the short term follow-up study original data from patients with arthroscopic meniscectomy in the early 80' s when the technique was new was compared to similar data from patients operated today, when the technique is in routine use. The operation time was shorter and the frequency of subtotal meniscectomy was less today. In contrast to the early 80's the procedure is entirely out-patient. However, recovery and in particular return to sports were delayed today in comparison to previously.

A less supervised rehabilitation is suggested to be the main cause to the delayed recovery and a generosity with supervised rehabilitation after arthroscopic meniscectomy is advisable.

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).

We have followed for 13 years a consecutive series of 31 patients who had open repair of a torn meniscus. They were between 13 and 43 years of age at the time of operation and all had intact stabilising ligaments. Comparison was made with a matched group of normal subjects of similar age and level of activity.

The total rate of failure after meniscal repair was 29%; three of the repaired menisci did not heal and six reruptured during the follow-up period. At follow-up 80% of the patients had normal knee function for daily activities. Radiological changes were found in seven. Two had reduction of the joint space (Ahlbäck grade 1), one with successful and one with failed repair. In the control group of uninjured subjects one knee showed Fairbank changes but none had changes according to Ahlbäck. The incidence of radiological changes did not differ between the group with meniscal repair and the control group but knee function was reduced after meniscal repair (p < 0.001).

We conclude that the long-term results of meniscal repair in stable knees are good with nearly normal function and a low incidence of low-grade radiological changes.

Sixty patients with stable knees and arthroscopic menisectomy were matched into two groups according to the presence of early degenerative changes at the operation. Patients with severe cartilage changes were excluded. The patients were between 20 and 40 years of age at the operation and no patient had previous surgery on the involved knee. The intraarticular findings were documented at surgery and the patients were re-examined 12 to 15 years after the meniscectomy. Pre-existing cartilage fibrillation at the meniscectomy did not seem to influence the long-term results. At the follow-up no difference was found between the groups at the physical examination, in subjective complaints, in knee function and activity or in radio-graphic findings. In the total group 62 % had early signs of arthrosis (Fairbank changes) and 42 % narrowing of the joint space (Ahlback grade 1-2) in the operated knee. No one had more severe changes. Radiographic signs of arthrosis were 4 times commoner in the operated knee compared to the non-operated kne after partial meniscectomy and 7 times commoner in the operated knee after subtotal meniscectomy. Arthrosis at the follow-up was seen three times more often in patients older than 30 years of age at surgery than in younger patients. The functional outcome was good and 70 % were still active in sports compared to 90 % before the operation.

We reexamined 43 patients with stable knees at a mean of 13 years after arthroscopic meniscectomy. The patients had a maximum age of 22 years at the operation and no patient had had previous surgery on the involved knee. At the follow-up examination, no differences in range of motion, muscle strength or tibial A/P displacement were seen between the operated and the nonoperated knees and 36 patients had no problem with their knee in daily life. Radiographic changes were found in the operated knee in 20 patients and in the nonoperated knee in 5 patients. 8 patients had a reduction of the joint space on the involved side, but none had more severe changes. Cartilage fibrillation at the index arthroscopy did not increase the radiographic changes at follow-up, but radiographic changes were commoner after subtotal meniscectomy (7/8) than after partial meniscectomy (17/35). These findings are similar to previous studies of arthroscopic meniscectomy of medium duration and do not differ considerably from studies of open meniscectomy.

Original data from 86 consecutive patients with arthroscopic meniscectomy 1980-81 was compared to similar data from 82 consecutive patients operated on 1995-1998. All knees were stable and without severe cartilage changes. In 1980 a follow-up examination was performed 10 (6-17) months after surgery and 1995 the patients answered two questionnaires 3 and/or more than 12 months after surgery. Age, sex and activity level before injury did not differ between the series and the distribution of meniscus tear types was similar.

In 1995 all patients were treated as outpatients while one third of the patients remained in hospital for 1-3 days in 1980. The operating time was shorter and the frequency of subtotal meniscectomy was less in 1995. Sick leave did not differ between the series and 2 out of 3 patients were back at work within one week. In 1995 almost half of the patients still had some knee problems 3 months after surgery but thereafter a substantial improvement was seen. The time to recovery was longer 1995 than in 1980. At the final follow-up the activity level and frequency of complete recovery did not differ between the series.

We conclude that the improved technique for arthroscopic meniscectomy during the last 15 to 20 years and less supervised rehabilitation has decreased the costs and freed resources for other patients. However, with the simplified rehabilitation, the previous opinion of a very fast recovery after arthroscopic meniscectomy has to be reevaluated.