No difference in time-dependent improvement in functional outcome following closing wedge versus opening wedge high tibial osteotomy: a randomised controlled trial with two-year follow-up.

AIMS: The aim of this prospective randomised study was to compare the time course of clinical improvement during the first two years following a closing or opening wedge high tibial osteotomy (HTO). It was hypothesised that there would be no differences in clinical outcome between the two techniques. PATIENTS AND METHODS: Between 2007 and 2013, 70 consecutive patients were randomly allocated to undergo either a closing or opening wedge HTO. All patients had medial compartment osteoarthritis (OA), and were aged between 30 years and 60 years. They were evaluated by independent investigators pre-operatively and at three and six months, and one and two years post-operatively using the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Oxford Knee Score (OKS), the Lysholm score, the Tegner activity score, the University of California, Los Angeles (UCLA) activity scale and range of movement (ROM). RESULTS: There were no significant differences at any time between the two techniques for any clinical outcome score (p > 0.05). The mean scores for all the systems, except UCLA and Tegner, significantly improved until six months post-operatively (p < 0.001). For some scores, the improvement continued until one and two years. CONCLUSION: This prospective randomised study suggests that there are no differences in the time course of the clinical improvement between the closing and opening wedge techniques for HTO during the first two post-operative years. Patients can expect continued improvement in physical function for between six months and one year after HTO regardless of the technique used. Cite this article: Bone Joint J 2017;99-B:1157-66.

Effect of trail design and grooming on the incidence of injuries at alpine ski areas.

OBJECTIVES: To identify the conditions at certain sites on slopes known as black spots for injury. METHOD: In the Hafjell and Voss alpine ski areas in Norway, 1410 skiing injuries were recorded from December 1990 through the 1996 season. In Hafjell, 183 of these injuries were plotted on an area map during the two first seasons. Similarly, in Voss, 214 injuries were plotted on an area map for two seasons. During the last three seasons in Hafjell, 835 ski injuries were related to 6712 snow grooming hours and 6,829,084 lift journeys. RESULTS: The mean injury rate was 2.2 injuries per 1000 skier days, and the mean injury severity score (ISS) was 3.1. Accumulations of injuries at three sites (black spots) were recorded on the Hafjell area map. These injuries represented 40% of all injuries in the alpine area (p<0.05). Seven injury accumulation sites were recorded on the alpine area map of Voss, representing 22% of the total injuries (p>0.05). Grooming of the slopes was rated poor for the 49% of injuries that occurred at the sites of injury concentration and significantly different (27%) from injuries that occurred at random in Hafjell. The corresponding values in Voss were 50% and 25% respectively. Grooming hours appeared to be inversely proportional to the number of injuries: R = -0.99 (p<0.02). The mean ISS declined significantly in Hafjell over the observation period (p<0.001). CONCLUSION: Inappropriate trail design and slope grooming seem to result in an accumulation of injuries at certain sites. Modification in construction and maintenance of the courses may reduce the number of injuries and mean ISS.

Organisation of safety measures in an Alpine World Junior Championship.

OBJECTIVES: To study the implementation of skiing safety during the Alpine World Junior Championship of 1995. METHODS: A map of the area was made with descriptions of the slopes and all its facilities and the security measures along the course. The number of competitors who started and any injuries reported were recorded in a questionnaire. RESULTS: A total of 452 girls and 546 boys started in the different races. Only four injuries were recorded, all in girls. The overall injury rate was 4 per 1000 runs. An injury rate of 8.3 per 1000 runs was recorded in the downhill. One skier had a possibly severe injury (ISS = 14) in the downhill; the rest of the injuries were minor (ISS = 1). The mean ISS was 4.3 and the total ISS was 17. CONCLUSIONS: A significantly higher injury rate was recorded for young female than young male racers. The injury rate was significantly higher in downhill than the other alpine disciplines in the Alpine World Junior Championship. The injury rate was not significantly different from that recorded one year previously for Olympic racers, and juniors therefore need the same safety measures as Olympic racers.

Activity-related knee injuries and pain in athletic adolescents.

By collecting data from 45 students at a ski high school, we found that a total of 73% of the students reported activity-related pain/injuries of the knee. Sixty-one percent had overuse injuries, 27% malalignment, and 12% had indistinct knee pain. Females suffered more knee pain/injuries (88%) than males (57%). Significantly higher Q-angle degrees were recorded for females (16) than for males (10). "Jumper's knee" was found in all competitive students with a KT manual maximum difference (MMD) of 3 mm or more (mean 4 mm), with a hard endpoint, whereas this was less common among the other competitive students (P < 0.05). The students were given counselling about training and physiotherapy. In the follow-up study 1 year later, a significant reduction of knee pain/overuse injuries, from 73% to 35%, was recorded. This may be related to better equipment, the development of techniques, and training of the muscles. A high volume of training and knee instability, with MMD of 3 mm or more, seemed to be correlated with an increased risk for "jumper's knee" and, possibly, for skiing injuries. By identifying those at increased risk, preseason recommendations can be made and ski injuries may be prevented.

Prospective study of changes in impairments and disabilities after anterior cruciate ligament reconstruction.

STUDY DESIGN: Single-group, repeated-measures prospective study. OBJECTIVES: To analyze changes in impairments and disabilities among patients with anterior cruciate ligament (ACL) reconstruction and to assess the relationships between the impairment and disability outcome measures from 3 months to 2 years following ACL reconstruction. BACKGROUND: Outcomes after ACL reconstruction can be categorized as impairments or disabilities. The relationship between impairments and disabilities may be crucial to understanding physical therapy interventions and predicting long-term outcome. METHODS AND MEASURES: Sixty patients who had undergone ACL reconstruction participated in the study. Impairment measures were range of motion, pain, knee-joint laxity, and muscle performance using isokinetic muscle tests. Disability measures were the Cincinnati knee score and lower limb performance using the triple-jump and stair-hop tests. Follow-up times were 3 and 6 months and 1 and 2 years after surgery. RESULTS: The Cincinnati knee score results show significant improvement 1 year after surgery (84.2 +/- 13.6) compared with 6 months (76.8 +/- 13.7) and 3 months (67.4 +/- 16.3) after surgery. Quadriceps total work (percentage of normal leg) significantly improved 2 years after surgery (92.6 +/- 14.1%) compared with 1 year after surgery (81.6 +/- 16.8%). Between 37 and 75% of the variability in the Cincinnati knee score could be explained by variation in the impairment variables, and quadriceps muscle performance and pain were the most significant predictors of disability. Extension deficit and pain at 3 months were significantly related to the Cincinnati knee score at the 2-year follow-up. CONCLUSIONS: Up to 2 years may be needed to regain normal quadriceps muscle performance following ACL reconstruction. Pain and quadriceps muscle performance explained most of the variability in the Cincinnati knee score.

Evaluation of skiing injuries by Injury Severity Score.

The goal of this study was to evaluate the Injury Severity Score (ISS) in an alpine area. Hafjell Alpine Centre was the 1994 Winter Olympic Alpine arena in Lillehammer. A total of 2,044,484 lift transportations and 183 injuries were registered in the two winter seasons 1991 and 1992. The injury rate was 1.8 injuries per 1000 skier days. The mean ISS was 3.6 per injury for this particular alpine area. Thirty-six per cent of the injured were women and 35.5% were between 15 and 19 years of age. There was no difference in mean ISS between male and female skiers, but mean ISS was higher in adolescents than in the other age groups. Injuries to the knee represented the single most frequently injured body region, but injuries to the abdomen had the highest mean ISS. Alpine skiers suffered more severe injuries than telemark and snowboard skiers. Severe injuries (ISS > 16) were recorded when unexpected objects, such as a grooming machine, a net, a root, etc., appeared on the slope. The Abbreviated Injury Scale (AIS) and ISS give us additional information about the condition of the slopes, and their use as a tool in preventing skiing injuries is recommended.

The effect of knee bracing after anterior cruciate ligament reconstruction. A prospective, randomized study with two years' follow-up.

The purpose of this prospective, randomized, clinical trial was to evaluate the effect of knee bracing after anterior cruciate ligament reconstruction. Sixty patients were randomized into one of two groups: Patients in the braced group wore rehabilitative braces for 2 weeks, followed by functional braces for 10 weeks, and patients in the nonbraced group did not wear braces. Data were recorded preoperatively, and postoperatively after 6 weeks, 3 and 6 months, and 1 and 2 years. The following outcome measures were used: KT-1000 arthrometry, the Cincinnati knee score, goniometry to record range of motion, computed tomography to determine thigh atrophy, Cybex 6000 isokinetic testing to evaluate muscle strength, three functional knee tests, and a visual analog scale to evaluate pain. At all follow-up times there were no significant differences between the two groups with regard to knee joint laxity, range of motion, muscle strength, functional knee tests, or pain. However, the Cincinnati knee score showed that patients in the braced group had significantly improved knee function compared with patients in the nonbraced group at the 3-month follow-up, even though the braced group showed significantly increased thigh atrophy compared with the nonbraced group at 3 months.

Dynamic hip screw with trochanteric stabilizing plate in the treatment of unstable proximal femoral fractures: a comparative study with the Gamma nail and compression hip screw.

OBJECTIVE: To compare the results after operative treatment of unstable per- and subtrochanteric fractures with the Gamma nail, compression hip screw (CHS), or dynamic hip screw with a laterally mounted trochanteric stabilizing plate (DHS/TSP). DESIGN: Prospective. PATIENTS: One hundred seventy patients with unstable trochanteric femoral fractures surviving six months after operation. Eighty-five patients were randomized to treatment with the Gamma nail (n = 50, Gamma group) or the compression hip screw (n = 35, CHS group) and compared with a consecutive series of eighty-five patients operated with the dynamic hip screw with a laterally mounted trochanteric stabilizing plate (DHS/TSP group) MAIN OUTCOME MEASUREMENTS: Radiographs were analyzed for fracture classification, evaluation of fracture reduction, implant positioning, later fracture dislocation, and other complications. Pre- and postoperative functional status of the patients were recorded, with a minimum of six months follow-up. RESULTS: Eighteen percent of the patients in the Gamma group, 34 percent in the CHS group, and 9 percent in the DHS/TSP group suffered significant secondary fracture dislocation during the six months follow-up, leading to a varus malunion, lag screw cutout, or excessive lag screw sliding with medialization of the distal fracture fragment. Two patients (4.0 percent) in the Gamma group suffered an implant-related femoral fracture below the nail, and one had a deep infection. The reoperation rates were 8.0 percent in the Gamma group, 2.9 percent in the CHS group, and 5.9 percent in the DHS/TSP group. All but one fracture in the Gamma and CHS groups and two fractures in the DHS/TSP group healed within six months. Approximately three-fourths of the patients had returned to their preoperative walking ability after six months, with a trend toward better functional outcome in the DHS/TSP group. Use of a TSP reduced the secondary lag screw sliding as compared with the conventional CHS, without affecting fracture healing. CONCLUSION: The TSP may be an aid in the treatment of these difficult fractures because the problem with femoral shaft fractures using the Gamma nail is avoided and the medialization of the distal fracture fragment frequently associated with the CHS is prevented.

Interference screw fixation of hamstring vs patellar tendon grafts for anterior cruciate ligament reconstruction.

The present study was designed to investigate the fixation strength of a quadruple semitendinosus-gracilis graft compared with a middle-third bone-patellar tendon-bone graft using a new interference screw developed to fix hamstrings grafts for ACL reconstructions (RCL Smith & Nephew Donjoy). Five pairs of human cadaveric knees from donors with a mean age of 43 (range 33-52) years were used. One knee of each pair was randomly allocated to be reconstructed on the femoral side with a semitendinosus-gracilis graft from the same donor using RCL screw fixation. As the control, the contralateral knee was correspondingly reconstructed with a bone-patellar tendon-bone graft using the same interference screw. The grafts were pulled out at a velocity of 30 mm/s by an axially applied load using a MTS machine. The mean (SD) failure load for the bone-patellar tendon-bone graft fixations was 505 (25) N, 110% stronger than the mean failure load for the semitendinosus-gracilis graft fixations, which was 240 (47) N (P = 0.003). The stiffness for the patellar tendon-bone graft fixations was 46 (11) N/mm, 120% stiffer than the semitendinosus-gracilis graft fixations, which was 22 (11) N/mm (P = 0.01). This study shows that the interference screw principle used for ACL reconstructions with hamstrings tendons is inferior to that for bone-patellar tendon-bone reconstructions although the screw was developed especially for soft-tissue fixation in bone tunnels.

Anterior cruciate ligament strength. Can it be estimated by non-destructive testing?

For structural and material bone strength, non-destructive tests exist, while no such tests have been developed for ligaments. In the present study we compared the geometry and bone mineral content (BMC) of the rat tibia with the tensile strength of the anterior cruciate ligament (ACL). A significant correlation was found between the mediolateral diameter of the tibial condyle and ACL load to failure (r=0.83). Calculating the area of the condyle as an ellipse increased this correlation to r=0.93. No significant correlation was found to BMC. If this correlation is also found in humans, the mediolateral tibial head diameter may be used to estimate the strength of the ACL non-destructively.

Injuries in military parachuting: a prospective study of 4499 jumps.

In this prospective study, the parachuting injuries which occurred during 2031 jumps in basic courses of free fall were compared with the injuries occurring during 2468 jumps for reserve paratroopers on training exercises. Fifty-eight injuries were recorded in 51 paratroopers. The ankle was most commonly affected, and 80 per cent of the injuries involved the lower extremity. Only 14 per cent of the injured troopers suffered severe injuries (fractures, knee ligament ruptures). The injury rate for paratroopers on basic courses (19.7 injuries per 1000 jumps) was significantly higher (P < 0.0001) than for those on training exercises (4.5 injuries per 1000 jumps). Similar observations were made for severe injuries (2.0 versus 1.2 injuries per 1000 jumps, respectively). The injury risk increased with age. Most of the injuries occurred on landing, and about 70 per cent were mainly caused by improper landing fall technique. The rate of serious parachuting injuries was low for Norwegian paratroopers.

Quadriceps muscle contraction protects the anterior cruciate ligament during anterior tibial translation.

The proposed skiing injury mechanism that suggests a quadriceps muscle contraction can contribute to anterior cruciate ligament rupture was biomechanically investigated. The effect of quadriceps muscle force on a knee specimen loaded to anterior cruciate ligament failure during anterior tibial translation was studied in a human cadaveric model. In both knees from six donors, average age 41 years (range, 31 to 65), the joint capsule and ligaments, except the anterior cruciate ligament, were cut. The quadriceps tendon, patella, patellar tendon, and menisci were left intact. One knee from each pair was randomly selected to undergo destructive testing of the anterior cruciate ligament by anterior tibial translation at a displacement rate of 30 mm/sec with a simultaneously applied 889 N quadriceps muscle force. The knee flexion during testing was 30 degrees. As a control, the contralateral knee was loaded correspondingly, but only 5 N of quadriceps muscle force was applied. The ultimate load for the knee to anterior cruciate ligament failure when tested with 889 N quadriceps muscle force was 22% +/- 18% higher than that of knees tested with 5 N of force. The linear stiffness increased by 43% +/- 30%. These results did not support the speculation that a quadriceps muscle contraction contributes to anterior cruciate ligament failure. In this model, the quadriceps muscle force protected the anterior cruciate ligament from injury during anterior tibial translation.

Injuries in powder skiing.

A Norwegian multicentre study of the winter 1985-1986, when 328 injured skiers were compared with a control population of 316 uninjured skiers, revealed a significantly lower injury risk for skiers on ungroomed than for skiers on groomed slopes. Thirty-seven skiers were injured on ungroomed slopes, and skiers aged 15-29 years were at risk. The population of uninjured powder skiers was significantly younger than the uninjured skiers on groomed slopes. Beginners were significantly overrepresented among the injured powder skiers, but the skiing ability for uninjured powder skiers was significantly higher than for uninjured skiers on groomed slopes. In conclusion, a lower injury risk was recorded for powder skiers than for skiers on groomed slopes, probably due to a higher skiing ability of the powder skiers.

Completion rates and injuries in alpine races during the 1994 Olympic Winter Games.

The starting lists for the alpine disciplines during the 1994 Olympic Winter Games in Lillehammer totalled 555 racers, but only 354 of them (64%) completed the different races. The race completion rate was 43% in the slalom, 51% in the giant slalom, 75% in the super giant slalom and 91% in the downhill. In combined downhill/slalom the race completion rate was 60%, but 96% in the downhill and 68% in the slalom part of the combination, respectively. Only three injuries were recorded, all in females. Including the training competitions a total of 1541 runs through the different alpine courses was recorded during the games. This means an injury rate of 1.9 injuries per 1000 runs. For downhill the injury rate was only 1.1 per 1000 runs. If the injury rate is related to the number of skiers who did not finish the race because of falls or skiing errors, the rate was 21.1 injuries per 1000 falls (skiing errors) for all alpine races. In conclusion, the race completion rate was twice as high in downhill as in slalom, and the injury rate was low.

Structural capacity of the knee to anterior cruciate ligament failure during quadriceps contraction. An in vivo study in the rat.

The effect of quadriceps contraction on the structural capacity of the knee joint loaded to anterior cruciate ligament (ACL) failure was studied in an in vivo rat model. In both knees of 20 rats the joint capsule and ligaments, except the ACL, were cut and the menisci resected by microsurgery. The rats were randomized to destructive testing of their ACLs either by femorotibial distraction or by anterior tibial translation at a displacement rate of 2.5 mm s-1 (60% s-1). The knee flexion during testing was 60 degrees. During loading of the right ACL, quadriceps contraction was induced by electrical stimulation of the femoral nerve. As control, the ACL of the left knee was loaded with relaxed quadriceps. The ultimate load for the knee to ACL failure when tested in tension by femorotibial distraction during quadriceps contraction was 140% higher than tested with the muscles relaxed (p = 0.0001). Energy absorption at failure during muscle contraction was 274% higher (p = 0.0001), and the linear stiffness increased by 59% (p = 0.0004). During testing by anterior tibial translation, neither linear stiffness nor ultimate load changed significantly, but the energy absorbed at failure was 46% (p = 0.02) higher during quadriceps contraction compared to testing with the quadriceps relaxed. These results showed that quadriceps contraction substantially increased the load carrying capacity of the rat knee subject to ACL failure when loaded by femorotibial distraction, but less when it was loaded by anterior tibial translation.

On-slope evaluation of release bindings for world-class alpine racers.

The alpine release bindings are set as indicated by the scale given in deca N.m (DIN) to the wanted release torque. The actual release torque of the toe unit was measured and calculated in 89 World Cup and national class racers during the Norwegian national championship in 1992. The deviation of the actual release torque from the desired release torque was calculated. The actual release torque was higher than the wanted release torque, with a mean deviation of 24% and a large dispersion from -28% to 130%. For the second testing, this deviation was reduced to 15%. The deviation of the actual release torque from the desired release torque was not related to age of the binding or class of skier (World Cup, European Cup or national class racers). Compared with a similar investigation 10 years ago, there was no significantly lower deviation.

A locked hip screw-intramedullary nail (cephalomedullary nail) for the treatment of fractures of the proximal part of the femur combined with fractures of the femoral shaft.

Twenty-seven patients with complex femoral fractures (combined shaft and proximal femoral fractures) were treated with a modified Grosse-Kempf slotted locking nail (cephalomedullary nail), wherein two screws were inserted in the hip. Four types of complex, multifocal femoral fractures were represented in the series. Eleven of the femoral shaft fractures were secondary to a previous, internally fixed, not yet united hip fracture (type I). Ten comminuted peritrochanteric fractures occurred in normal bone (type II). Three similar fractures were pathologic because of metastasis. Two patients had an ipsilateral fracture of the femoral shaft and the trochanteric area (type III), and one of the shaft and the femoral neck (type IV). Locking was made static in 24 cases. Additional cerclage wiring was used in three type II fractures. Five complications were as follows: one cutting out of a screw in the femoral head, two fractures of the nail, one deep venous thrombosis, and one wound hematoma. Reoperations were two salvage operations using a new nail and one evacuation of hematoma. One patient with multiple injuries and four elderly patients died within 2 months. Eighteen patients with fractures in normal bone were followed for a median of 20 (6 to 37) months. All fractures united. Two nails were removed. The end result was excellent in ten patients, good in seven, and fair in one (2-cm shortening and 20-degree external rotation). We conclude that a locked intramedullary construct with locking screws in femoral neck and distal femur controls a complex fracture situation well.

Effect of quadriceps or hamstring contraction on the anterior shear force to anterior cruciate ligament failure. An in vivo study in the rat.

We studied the effect of quadriceps or hamstring contractions on the anterior tibial shear load to anterior cruciate ligament failure in an in vivo rat model. In both knees of 20 Wistar rats the joint capsule and ligaments, except the anterior cruciate ligaments, were cut and the menisci resected. In 10 rats the right ligament was loaded to failure by anterior translation of the tibia relative to the femur in a testing device during hamstring contraction induced by electrical stimulation of the ischiatic nerve. In the other 10 rats, the right ligament was loaded to failure correspondingly during quadriceps contraction induced by electrical stimulation of the femoral nerve. The loading rate was 2.5 mm s-1 (approximately 0.6(-1)). The knee flexion during testing was 30 degrees. As control, the anterior cruciate ligament of the left knee was loaded correspondingly with relaxed muscles. The ultimate load for the ACL tested during hamstring contraction was 1.5 times higher than when tested with the hamstrings relaxed, more than double the energy was absorbed at failure and the linear stiffness was 1.2 times higher. During testing with quadriceps contraction, no differences in the structural properties were found, compared to testing with the quadriceps relaxed. Our findings show that hamstring contraction helps to resist anterior tibial shear force at 30 degrees knee flexion in rats thus protecting the anterior cruciate ligaments. Quadriceps contraction in this situation does not affect anterior shear force to ligament failure.