Changes in biomechanical risk factors for knee osteoarthritis and their association with 5-year clinically important improvement after limb realignment surgery.

OBJECTIVE: To evaluate 5-year outcomes after lower limb realignment and test the hypothesis that surgery-induced changes in selected biomechanical risk factors for medial knee osteoarthritis (OA) are associated with clinically important improvements. DESIGN: We prospectively evaluated patient-reported outcomes, full-limb standing radiographs and gait biomechanics before, 6 months (surgery-induced change) and 5 years after medial opening wedge high tibial osteotomy (HTO) in 170 patients (46.4 ± 8.9 years, 135 males) with knee OA and varus alignment. Logistic regression tested the associations of 6-month changes in mechanical axis angle and knee adduction moment with achieving an increase of ≥10 points in the Knee injury and Osteoarthritis Outcome Score (KOOS)4 at 5 years, with and without adjusting for covariates. Gait data were also compared to existing data from healthy controls. RESULTS: Mean 5-year changes (95% confidence interval (CI)) were: KOOS4: +14.2 (10.8, 17.6); mechanical axis angle: +8.21° (7.58, 8.83); knee adduction moment: -1.49 %BW*Ht (-1.35, -1.63). The postoperative knee adduction moments were typically lower than values for healthy controls. When divided into quartiles, although all strata improved significantly, patients with reductions in knee adduction moment of 1.14-1.74 %BW*Ht (neither largest nor smallest changes) had highest 5-year KOOS4 scores. The 6-month change in knee adduction moment (odds ratios (OR) = 0.38; 95% CI: 0.22, 0.67), preoperative KOOS4 (OR = 0.96; 95% CI: 0.94, 0.99) and preoperative medial tibiofemoral narrowing grade (OR = 0.62; 95% CI: 0.37, 1.00) were negatively associated with having a 5-year clinically important improvement (C-statistic = 0.70). CONCLUSIONS: Substantial improvements in biomechanical risk factors and patient-reported outcomes are observed 5 years after medial opening wedge HTO. The surgery-induced change in load distribution during walking is significantly associated with long-term clinically important improvement.

High tibial osteotomy: evolution of research and clinical applications--a Canadian experience.

PURPOSE: This narrative review describes experiences at the Fowler Kennedy Sport Medicine Clinic (FKSMC) with high tibial osteotomy (HTO) for patients with varus gonarthrosis, with particular focus on research published from the unit that has guided practice. METHODS: The goals of surgery are to improve alignment of the weight bearing axis of the lower limb to lessen the load on the medial tibiofemoral compartment and thereby decrease these important risk factors for disease progression. The overall aims are to improve knee function and delay or even prevent the eventual need for arthroplasty. To achieve these aims, a medial opening wedge osteotomy is utilised, deliberately avoiding an over correction of the lower limb, but tailoring the angle of correction to an individual patient's characteristics. With such an approach, patients with a broad range of characteristics (including age, BMI and lateral compartment involvement) can benefit from the procedure. In addition, the HTO can be used with concomitant procedures to address specific presentations, such as large deformities and instability. RESULTS: The results suggest that correction to a slight valgus alignment produces approximately 50% reduction in medial compartment loads during gait with large, clinically important improvements in patient-reported outcomes at 2-years postoperatively. In patients with substantial bilateral varus deformity, unilateral surgery can lead to increased dynamic knee joint loads on the nonoperative limb after surgery. This means that such patients require the close monitoring of both limbs and consideration of a staged, bilateral procedure if necessary. In patients requiring bilateral surgery, similar results after bilateral HTO to those after unilateral surgery have been reported. For patients requiring large corrections, the need for a concomitant tibial tubercle osteotomy to reduce the potential for iatrogenic patella infera is considered. Finally, HTO procedures can also be used in patients with instability, either to alter both sagittal and coronal alignment to correct instability in complex ligament deficiencies or to undertake simultaneous HTO and ACL reconstruction. CONCLUSIONS: HTO is being used both alone and in conjunction with concomitant procedures with good clinical results. While continued investigation into patient selection and outcomes are required, current research indicates that HTO offers at least a partial solution for the patient with varus gonarthrosis to prolong the life of their native knee joint. LEVEL OF EVIDENCE: V.

A very unusual case history.

The above case history demonstrates well how a severe potentially lethal medical condition can often develop quite insidiously with what appeared to be quite common and everyday symptoms initially. In my opinion, one of the potential problems with the management of this lady was the number of different doctors she consulted within the practice, both military and locum (11 in total during 2007) resulting in lack of continuity of case. However, it is impossible to ascertain quite when the vasculitis actually developed or whether it could have been suspected earlier. In nearly 30 years as a doctor, this is the first case of Wegener's that I have knowingly come across. Perhaps because of such rarities, this is what makes being a GP such an interesting and challenging role. So next time you see someone with a runny nose and dry cough .... think again!

Exercise Maganga Mercury 23 January-10 February 2006.

It is very likely that Royal Navy doctors will be called upon more and more in the future to work on similar overseas exercises. I found the experience immensely challenging and educational and would have no hesitation in volunteering for further deployments or recommending other RN doctors to do the same.

The effect of fixation technique on graft position in anterior cruciate ligament reconstruction.

The purpose of this paper was to determine the extent to which the technique used in ACL reconstruction and fixation influences graft placement. This is a Comparative Radiographic cohort study. Precise graft placement is one of the most crucial components of a successful anterior cruciate ligament (ACL) reconstruction. Two commonly used techniques of ACL reconstruction are arthroscopic bone-patellar tendon-bone (B-PT-B) autograft with interference screw fixation and semi-tendinosus and gracilis (ST + G) tendon autograft with endobutton femoral and multiple staple belt buckle tibial fixation. Using radiographic measurements of bone tunnel position following ACL reconstruction this study quantified the extent to which these techniques influenced graft placement. Femoral and tibial tunnel position in ACL reconstruction was determined using the post-operative radiographs of 40 male patients who had undergone ACL reconstruction (20 B-PT-B and 20 ST + G). The primary outcome measure was location of bone tunnel position following ACL reconstruction. Measurements were based on the guidelines of Amis et al. Femoral tunnel position of B-PT-B grafts was an average of 9.36% more anterior in the sagittal plane than with ST + G grafts. The mean position of B-PT-B grafts was at 31.11% (SD = 5.45%). The mean position of the ST + G grafts was 21.76% (SD = 6.62%). This difference between the two was found to be significant (p < .001). As demonstrated by this study, placement and orientation may vary to accommodate technique and fixation. Clinical outcomes measured were similar in both groups.

Effect of fatigue on knee proprioception: implications for dynamic stabilization.

The high incidence of injuries that occur later during a session of sports or recreational activities suggests that fatigue may contribute to altered neuromuscular control of the lower limb and an individual's subsequent altered ability to dynamically stabilize the knee joint. One possible mechanism is a fatigue-mediated alteration in proprioception. This paper reviews experimental evidence of fatigue-induced changes in knee joint position sense and movement sense, or kinesthesia. We will discuss the possible physiological mechanisms behind these changes, including the role of joint and muscle receptors in proprioception and neuromuscular control of the knee, and the role of fatigue in changes in afferent output from muscle and joint receptors. We will then explore the implications that alteration in proprioception may have for dynamic stabilization of the knee joint.

Elastomeric pumps for ambulatory patient controlled regional analgesia.

PURPOSE: To report our experience with the use of the (Eclipse) elastomeric pump for ambulatory Patient Controlled Regional Analgesia (PCRA) METHOD: After a pilot study using this device in patients admitted to the hospital, seven patients received PCRA at home using the elastomeric pump. Patients with a variety of continuous regional anesthetic blocks were sent home with written and verbal instructions regarding the use of this device, boluses, side effects of local anesthetics and removal of block catheters. Patients were contacted daily to collect data with regards to the efficacy of the block, problems associated with the use of this device and their satisfaction with the method of analgesia. RESULTS: During the pilot study there were two catheter disconnections requiring rescue analgesics. Two patients had the entire contents of the bulb delivered over several minutes. Among the seven patients receiving PCRA at home, one patient had to be admitted to the hospital. One patient had block catheter slip out during transit. The volume delivered could not be measured. Patients found it difficult to know if the drug had been delivered. Three patients noted that the pumps were empty earlier than expected. One patient found it difficult to change the bulb. No patient had difficulty with catheter removal or with bolusing. CONCLUSIONS: PCRA offers excellent postoperative analgesia at home. Elastomeric pumps facilitate PCRA but are imprecise with drug delivery and may not be safe for epidural infusions. The safety of this device for peripheral nerve blocks should be evaluated further.

Management of injuries to the anterior cruciate ligament: results of a survey of orthopaedic surgeons in Canada.

OBJECTIVE: To identify the approaches to management of anterior cruciate ligament (ACL) injury by Canadian orthopedic surgeons. METHODS: A questionnaire was mailed to 234 physicians randomly chosen from the Canadian Orthopaedic Association directory to obtain the following information: 1) how orthopaedic surgeons diagnose acute hemarthroses; 2) how patients in any of three common ACL injury scenarios would be managed; 3) what variations exist in surgical technique; and 4) how patient variables such as age, gender, and alignment influence the decision-making process. RESULTS: The return rate was 72%, and 56% of respondents were from academic centers. Patients such as those described in the protocol are routinely managed by 80% of the respondents. The diagnosis of acute hemarthrosis is predominantly made by means of clinical examination and radiographs. Magnetic resonance imaging (MRI) is used occasionally by 43% and routinely by 6% of those who responded; arthroscopy is used routinely by 24%. For the competitive athlete with a complete ACL tear, 64% would recommend reconstruction and 33% would recommend bracing and rehabilitation. For reconstruction, 59% would use bone-patellar tendon-bone (B-PT-B) autograft and 32% would use hamstring tendon autograft; 40% would incorporate the ACL stump during reconstruction. Of the respondents, 77% would advocate ACL reconstruction for competitive athletes with chronic ACL injury. Of these, 63% would use B-PT-B autograft and 27% would use hamstring tendons. If bracing and rehabilitation failed, 98% would recommend ACL reconstruction. In ACL reconstruction, synthetic augmentation would be used by 12% in chronic cases and by 16% in acute cases. In making the decision to perform ACL reconstruction, 53% consider limb alignment to be important and 67% consider moderate patellofemoral pain to be important. Seventy-one percent are influenced by patellofemoral pain when choosing a surgical technique, with a trend toward semitendinosis autograft rather than B-PT-B autograft reconstruction. For the 8-year-old child with an acute ACL injury, 63% of the respondents would recommend rehabilitation and bracing. For the 14-year-old, 45% would recommend rehabilitation and bracing and 37% would recommend ACL reconstruction after physeal closure. CONCLUSION: The results of the survey indicate that, with respect to some of the issues, there is a wide variation in management of acute and chronic ACL injuries among Canadian orthopedic surgeons. Future research and randomized, controlled clinical trials should be directed toward these areas.

Occult osteochondral lesions after anterior cruciate ligament rupture. Six-year magnetic resonance imaging follow-up study.

Twenty-three patients with acute anterior cruciate ligament injuries, normal radiographs, and occult osteochondral lesions revealed by magnetic resonance imaging were reviewed 6 years after initial injury and anterior cruciate ligament hamstring autograft reconstruction. Each patient completed the Mohtadi Quality of Life outcome measure for anterior cruciate ligament deficiency, underwent clinical examination, and had a repeat magnetic resonance imaging scan. The index and follow-up magnetic resonance imaging scans were compared with respect to cartilage thinning and marrow signal. A significant number of patients had evidence of cartilage thinning adjacent to the site of the initial osteochondral lesion. Marrow signal changes persisted in 15 (65%) of the patients. Clinical comparison of patients with normal cartilage with those who had cartilage thinning revealed similar results on both KT-1000 arthrometry and on the Mohtadi outcome measure. This suggests that the initial injury resulted in irreversible changes in the knee. Injuries causing marrow signal changes may result in an alteration in the load-bearing properties of subchondral bone, which in turn allow for changes in the overlying cartilage. Further follow-up will determine the clinical significance of changes detected by magnetic resonance imaging.

The anterior horn of the medical meniscus. An anatomic study of its insertion.

A morphologic study of 48 cadaveric knees was performed to more accurately define the osseous and soft tissue anatomy of the insertion of the anterior horn of the medial meniscus. Soft tissue relationships of the anterior horn of the medial meniscus to the anterior cruciate ligament and the lateral meniscus were examined. Four tibial insertion locations of the medial meniscus were identifiable by bony landmarks. Type I insertions were located in the flat intercondylar region of the tibial plateau; type II occurred on the downward slope from the medial articular plateau to the intercondylar region; type III occurred on the anterior slope of the tibial plateau; there was no firm bony insertion of the anterior horn in type IV. The occurrence for type I was 59% (20 of 34); type II, 24% (8 of 34); type III, 15% (5 of 34); and type IV, 3% (1 of 34). The variance in insertion patterns may have clinical applications for patients with atypical anterior knee pain and for performing meniscal allograft. Type III and type IV insertions may be unable to resist peripheral extrusion of the loaded meniscus, placing it at risk for anterior subluxation and causing anterior knee pain in specific cases. Awareness of these patterns may be valuable in medial meniscus harvest and transplantation.

Effect of a neoprene sleeve on knee joint position sense during sitting open kinetic chain and supine closed kinetic chain tests.

The primary objective of the present study was to compare the effect of a neoprene sleeve on knee joint position sense during a sitting open kinetic chain test and a supine closed kinetic chain test. Young (24 +/- 2 years old), healthy subjects (18 men and 18 women) performed knee joint angle replication tests during open kinetic chain knee extension (sitting) and closed kinetic chain leg press (supine with an axial load of 15% body weight) before and after application of a neoprene sleeve over the dominant knee. The improvement in ability to replicate joint angles after application of the sleeve (sleeve effect) was significantly less during the supine closed kinetic chain test (0.3 degree +/- 1.4 degrees) than during the sitting open kinetic chain test (1.2 degrees +/- 1.1 degrees). The sleeve effect was inversely related to subjects' performance without the sleeve during both the sitting open kinetic chain and supine closed kinetic chain tests, suggesting that some people may derive greater benefit from the sleeve than others. Although the sleeve effects were small, particularly during the supine closed kinetic chain test, 72% of subjects felt that the sleeve improved their overall test performance. Future research is needed to establish the functional relevance of the small sleeve effects observed and to identify the characteristics of people who might derive greatest benefit from sleeve use.

Anterior cruciate ligament injuries in the skeletally immature patient.

Anterior cruciate ligament injury in the skeletally immature is becoming increasingly recognized and reported. History taking and physical examination based on the principles of ACL injuries in adults, with adjuncts such as arthroscopy and MRI, are effective in diagnosing ACL injury in the young patient. Evaluation of the young patient's true level of skeletal immaturity by comparison with family growth history, examination for signs of sexual maturity, and radiographic evaluation is critical. The risk of physeal damage with surgical treatment is related to the immaturity of the distal femoral and proximal tibial physes. The functional results of nonsurgical treatment of ACL injury, either as an attempt at definitive treatment or as a temporizing plan until skeletal maturity occurs, are poor and the risks of reinjury and further meniscal and cartilage damage are significant. Surgical treatment for primary repair or extra-articular reconstruction alone has not proven to be efficacious. In the adolescent patient who is approaching skeletal maturity, risk of physeal injury is low and intra-articular reconstruction can be performed as in the adult patient. Results with respect to decreased laxity and return to athletic activities mirror those described in adults. In patients with significant growth remaining, however, surgical treatment carries much higher risks of physeal damage and subsequent deformity. Yet, as noted above, intra-articular reconstruction in truly skeletally immature patients using a soft-tissue graft through a transphyseal tibial tunnel of moderate or small diameter and the over-the-top position on the femur has not been shown to cause early physeal closure, limb-length discrepancy, or angular deformity. In humans, the maximum diameter of graft tunnel that will not cause physeal closure has not been determined Animal studies have shown that the tibial physis can be very sensitive to drilling. Therefore it is wise to use moderate tunnel diameters. Bone-patellar tendon-bone grafts have been used with success in patients closer to skeletal maturity. Their use has not been reported in the very skeletally immature knee and cannot be recommended because of the presumed high risk of physeal closure with a bone plug traversing the physis. It is hoped that improved understanding of the ACL injury in the skeletally immature patient will provide treatment options that will restore enduring knee function and prevent early arthrosis.

The outcome of operatively treated anterior cruciate ligament disruptions in the skeletally immature child.

The purpose of this study was to evaluate the outcome of transphyseal ligament reconstruction in skeletally immature children with midsubstance anterior cruciate ligament (ACL) disruption. Five consecutive patients (mean age, 12.9 years; range, 8 to 14 years) with radiographically documented "wide" open growth plates and a minimum of 5 cm of expected remaining growth, underwent intra-articular reconstruction of the ACL. Operative treatment included three ACL reconstructions using hamstring tendons and two with quadriceps patellar tendon. All involved a centrally placed 6-mm or smaller tibial drill hole through an open physis and graft placement in an over-the-top position on the femur. At an average follow-up of 7.4 years (range, 4.5 to 9.9 years), no patient had a positive anterior drawer, Lachman, or pivot shift test. On KT-1000 arthrometer testing, all patients had 3 mm or less of increased anterior-posterior displacement (mean +/- SD = 1.0 +/- 1.6 mm). Magnetic resonance imaging showed that four tibial physes had fused in a symmetric fashion and one was still open. Orthoroentgenograms showed that no patient had a significant leg length discrepancy (-0.8 mm +/- 3.4 mm). The mean increase in height postoperatively was 17.7 cm (range, 7.6 to 31.0 cm). Overall, using the International Knee Documentation Committee (IKDC) evaluation form, there were four patients with grade A and one with grade C. The one patient with a poor IKDC grade had sustained a subsequent patellar dislocation with osteochondral fracture. In conclusion, ACL reconstruction using small drill holes placed through open tibial physes does not seem to adversely affect outcome or future growth.

Effects of fatigue on knee proprioception.

OBJECTIVE: To investigate the effects of muscular fatigue on knee joint proprioception. DESIGN: Prospective study. SETTING: Exercise physiology laboratory. PARTICIPANTS: Sixteen (eight men and eight women) healthy volunteers ages 19-27 years, with no history of neuromuscular disorders, vestibular disorders, or lower limb injuries (e.g., ligament/meniscus tear). INTERVENTION: Three separate fatigue protocols [ramp test (RT), continuous test (CT), and interval test (IT)] were performed. All tests consisted of lower limb cycling on a computer-driven cycle ergometer (Lode). The RT was used to calculate the maximal aerobic power (VO2max) and determine the work rates for the CT and IT. Work rate for the RT increased 20/25 W/min to maximal exhaustion. The CT consisted of cycling at 80% VO2max until maximal exhaustion. The IT consisted of cycling alternately at 120% VO2max and at 40% VO2max for 30 s each to the point of maximal exhaustion. MAIN OUTCOME MEASURE: In the standing position, subjects were instructed to perform a two-legged squat to specific knee flexion angles. The absolute angular error (AAE) was measured for each test angle using an electrogoniometer (Penny & Giles, Blackwood, Gwent, U.K.) placed laterally across the dominant knee joint. AAE was defined as the absolute difference between test angle and subject perceived angle of knee flexion. RESULTS: A statistically significant increase in AAE after the RT (1.0 +/- 0.66 degree, p < 0.01), CT (0.70 +/- 0.66 degree, p < 0.03), and IT (1.24 +/- 0.79 degrees, p < 0.01) protocols was observed in the male subjects. Female subjects reported a statistically significant increase in AAE after the CT (0.73 +/- 0.73 degree, p < 0.03) and IT (1.1 +/- 0.89 degrees, p < 0.01) protocols and a nonsignificant increase in AAE (0.19 +/- 0.70 degree, p > 0.5) after the RT protocol. CONCLUSION: These findings suggest that exercising to fatigue may produce a change in subjects' reproduction ability of knee joint angles. This may represent a decline in proprioceptive function after heavy exercise bouts. Whether this suggested proprioceptive decline is at the clinical significance level (e.g., significantly altering joint stability and motion) cannot be determined from the present findings.

Anterior cruciate ligament tear: prospective evaluation of diagnostic accuracy of middle- and high-field-strength MR imaging at 1.5 and 0.5 T.

PURPOSE: To compare the diagnostic efficacy of current-generation middle- and high-field-strength magnetic resonance (MR) imagers in the diagnosis of anterior cruciate ligament (ACL) tears. MATERIALS AND METHODS: In 114 of 230 patients referred for knee imaging, MR imaging at 0.5 and 1.5 T was performed with identical sequences but with a slightly longer total imaging time and bandwidth optimization at 0.5 T. Radiologists were blinded to diagnosis and field strength. Sensitivity, specificity, and accuracy were determined, and ACL tear was confirmed by means of arthroscopy and pathology. RESULTS: There was no difference between the field strengths in accuracy, sensitivity, or specificity for the diagnosis of ACL tears in 86 patients with disrupted ACLs and 28 patients with intact ACLs. Accuracy for all ACL tears was 90% at 0.5 T and 91% at 1.5 T. Similarly, there were no differences in diagnosis of meniscal tears (79 with, 149 without) or posterior cruciate ligament tears (seven with, 107 without). CONCLUSION: Higher field strength does not confer higher accuracy in the diagnosis of ACL tears at MR imaging.

The effect of cast immobilization on meniscal healing. An experimental study in the dog.

A 1.5-cm longitudinal, full-thickness incision was made in the vascularized portion of the medial meniscus in 20 adult dogs and anatomically repaired. Postoperatively, the animals were either placed in a long leg cast (N = 9) or mobilized immediately (N = 11). The animals were sacrificed at 2 weeks (6 dogs), 4 weeks (6 dogs), or 10 weeks (8 dogs). Five medial menisci from the nonoperated side were used as controls. Collagen content was measured using a digital image analysis system, and the collagen percentage in the repair tissue in each postoperative treatment group was compared. In the 2-week and 4-week groups, there was no statistically significant difference in the percentage of collagen between those animals immobilized versus those that had early mobilization. The animals in the 10-week group that were mobilized had a significantly greater collagen percentage in the healing meniscal incision than those that were cast immobilized (44.6% +/- 10% versus 27.0% +/- 11%, P < 0.0001). There was no significant difference in the collagen percentages between the mobilized 10-week group and the contralateral control menisci group. All other menisci had a decreased collagen percentage compared with the controls. Prolonged immobilization decreases collagen formation in healing menisci. Thus, our results suggest that patients undergoing isolated meniscal repair either be immediately mobilized after surgery or immobilized for short periods only.