KOOS pain as a marker for significant knee pain two and six years after primary ACL reconstruction: a Multicenter Orthopaedic Outcomes Network (MOON) prospective longitudinal cohort study

OBJECTIVE

The prevalence of radiographic osteoarthritis (OA) after anterior cruciate ligament reconstruction (ACLR) approaches 50%, yet the prevalence of significant knee pain is unknown. We applied three different models of Knee injury and Osteoarthritis Outcome Score (KOOS) thresholds for significant knee pain to an ACLR cohort to identify prevalence and risk factors.

DESIGN

Multicenter Orthopaedic Outcomes Network (MOON) prospective cohort patients with a unilateral primary ACLR and normal contralateral knee were assessed at 2 and 6 years. Independent variables included patient demographics, validated Patient Reported Outcomes (PRO; Marx activity score, KOOS), and surgical characteristics. Models included: (1) KOOS criteria for a painful knee = quality of life subscale <87.5 and ≥2 of: KOOSpain <86.1, KOOSsymptoms <85.7, KOOSADL <86.8, or KOOSsports/rec <85.0; (2) KOOSpain subscale score ≤72 (≥2 standard deviations below population mean); (3) 10-point KOOSpain drop from 2 to 6 years. Proportional odds models (alpha ≤ 0.05) were used.

RESULTS

1761 patients of median age 23 years, median body mass index (BMI) 24.8 kg/m(2) and 56% male met inclusion, with 87% (1530/1761) and 86% (1506/1761) follow-up at 2 and 6 years, respectively. At 6 years, n = 592 (39%), n = 131 (9%) and n = 169 (12%) met criteria for models #1 through #3, respectively. The most consistent and strongest independent risk factor at both time-points was subsequent ipsilateral knee surgery. Low 2-year Marx activity score increased the odds of a painful knee at 6 years.

CONCLUSIONS

Significant knee pain is prevalent after ACLR; with those who undergo subsequent ipsilateral surgery at greatest risk. The relationship between pain and structural OA warrants further study.

Revision ACL reconstruction outcomes: MOON cohort

Many clinicians believe that the results of revision anterior cruciate ligament (ACL) reconstruction compare unfavorably with primary ACL reconstruction. However, few prospective studies have evaluated revision ACL reconstruction using validated patient-based metrics. This study was performed to evaluate and compare the results of revision ACL reconstruction and primary ACL reconstruction. The Multicenter Orthopaedic Outcomes Network consortium is an NIH-funded, hypothesis-driven, multicenter prospective cohort study of patients undergoing ACL reconstruction. All patients preoperatively complete a series of validated patient-oriented questionnaires. At scheduled 2-year follow-up all patients are given the same series of questionnaires to complete. The study evaluated the results of 2-year follow-up of revision ACL reconstruction performed in 2001. Parameters evaluated included Marx activity level, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) scores. For this study 446 subjects met inclusion criteria; 2-year follow-up was obtained on 393 (88%). The study group consisted of 55% males with median age of 22 years. There were 33 revision ACL reconstruction cases, for which follow-up was available for 29 (88%). Median baseline Marx (interquartile range) was 12 (8 to 16) and 12 (6 to 16) for the primary ACL reconstruction and revision ACL reconstruction groups, respectively (p= 0.81). At 2 years, median Marx was 9 (4 to 13) and 5 (0 to 10) for the primary ACL reconstruction and revision ACL reconstruction groups, respectively (p= 0.03). Median 2-year IKDC was 75.9 (revision) versus 83.9 (primary) (p=0.003). Median KOOS subscale Knee Related Quality of Life (KRQOL) at 2 years was 62.5 (revision) versus 75 (primary) (p < 0.001), subscale Sports and Recreation was 75 (revision) and 85 (primary) (p = 0.005), subscale Pain was 83.3 (revision) and 91.7 (primary) (p= 0.002). Marx activity score declined at 2-year follow-up in revision ACL reconstruction compared with primary ACL reconstruction. IKDC and KRQOL were significantly decreased in revision ACL reconstruction compared with primary ACL reconstruction at 2-year followup. Revision ACL reconstruction resulted in a significantly worse outcome as measured by these patient-based measures at 2 years.

Articular cartilage contact pressure after tibial tuberosity transfer. A cadaveric study

Medial transfer of the tibial tuberosity has been commonly used for treatment of recurrent dislocation of the patella and patellofemoral malalignment. In this study, six fresh human cadaveric knees were used. Static intrajoint loads were recorded using Fuji Prescale pressure-sensitive film for contact pressure and contact area determination in a closed kinetic chain knee testing protocol. Peak pressures, average contact pressures, and contact areas of the patellofemoral and tibiofemoral joints were calculated on native intact knee specimens and after tibial tuberosity transfer. All native intact knee specimens had a normal Q angle. Medialization of the tibial tuberosity significantly increased the patellofemoral contact pressure. Medial displacement of the tibial tuberosity also significantly increased the average contact pressure of the medial tibiofemoral compartment and changed the balance of tibiofemoral joint loading. The results of our study suggest that caution should be used when transferring a patellar tendon in the face of a preexisting normal Q angle as this will result in abnormally high peak pressure within the tibiofemoral joint. Overmedialization of the tibial tuberosity should be avoided in the varus knee, the knee after medial meniscectomy, and the knee with preexisting degenerative arthritis of the medial compartment.

Anterior cruciate ligament injuries in the skeletally immature patient

Injuries to the anterior cruciate ligament in children and youth pose a complex clinical challenge. The literature does not provide the clinician with a well-defined natural history or pathoanatomy, nor does it show agreement as to the outcomes of various treatment choices. Decision making is made difficult by the patients' skeletal and emotional immaturity and by associated intra-articular fracture, physeal fracture, and combination injuries. In an effort to place the problem of ACL injury in children and youth into some perspective and to present an algorithm for management, this article reviews issues in its diagnosis, classification, anatomy, mechanism of injury, and management.

Characterization of hamstring reflexes during anterior cruciate ligament disruption: in vivo results from a goat model

The existence of an anterior cruciate ligament-hamstring reflex arc, the extent to which these reflexes can protect the knee, and the extent to which they are affected by rupture of the anterior cruciate ligament remain controversial. We evaluated the temporal components of the anterior cruciate ligament-hamstring synergy by simulating an injury to the ligament in a goat model. Reflexive hamstring activation in anesthetized goats was evaluated when the anterior cruciate ligament was loaded with static subfailure, dynamic subfailure, and dynamic failure loads. Reflexive hamstring activation was not found in response to static subfailure loading but was observed in response to dynamic subfailure and failure loading. The latency of the reflex evoked by dynamic failure loading was shorter than that evoked by dynamic subfailure loading. The findings suggest that the extent to which the hamstring reflexes can protect the knee may be bounded by the ability of these muscles to generate force rapidly and the amplitude and time-course of the loads applied to the knee joint. The present data present a framework for further investigation of the contribution of anterior cruciate ligament-hamstring reflexes to the stability of the knee joint under high loads and loading rates.

Patella-tibial transfixation for posterior cruciate ligament repair and reconstruction: a biomechanical analysis

The posterior cruciate ligament (PCL) restricts posterior translation of the tibia on the femur. Because flexion of the knee increases tension on the PCL, the knee is usually immobilized in extension after PCL repair or reconstruction. Patella-tibial transfixation (olecranization), however, has been proposed to reduce the tension on the PCL without requiring immobilization of the knee. The objective of this study was: (1) to evaluate the distribution of strain in the anterolateral and posterior oblique fiber bundles of the PCLs in eight cadaveric knees before and after olecranization and (2) to measure the patellofemoral contact pressures at various degrees of knee flexion. Olecranization significantly (P < 0.05) reduced the strain on the anterolateral fiber bundles of the PCL at 15 degrees -45 degrees of flexion. No significant strain reduction was observed in the posterior oblique fiber bundles. Patellofemoral contact pressures measured from digitized Fuji sensitive film indicated significantly increased contact pressures (P < 0.05) following olecranization from 0 degrees -60 degrees of knee flexion. Increased parapatellar soft tissue tightness limited knee flexion to 90 degrees and patella lift-off occurred at 75 degrees. Although olecranization of the patella does reduce strain on the intact PCL within a selected range of motion, the beneficial effect of allowing early motion may be negated by the potentially harmful effects imposed upon the patellofemoral articular cartilage by increased contact pressures.

Effectiveness of bupivacaine administered via femoral nerve catheter for pain control after anterior cruciate ligament repair

STUDY OBJECTIVE

To evaluate the quality of pain control achieved with continuous local anesthetic infusion via a femoral nerve catheter, and to determine the optimum concentration of bupivacaine necessary to maintain pain control after full surgical anesthesia is established with 0.5% bupivacaine.

DESIGN

Randomized, prospective study.

SETTING

Tertiary care teaching center.

PATIENTS

25 ASA physical status I and II patients scheduled to undergo arthroscopically-aided anterior cruciate ligament (ACL) reconstruction by one surgeon, and who were willing to accept a femoral nerve catheter for postoperative pain control.

INTERVENTIONS

All patients received general anesthesia with propofol/alfentanil (10 ml/1 ml) mixture and nitrous oxide/oxygen (60%/40%) mixture via endotracheal tube. After induction of general anesthesia, a femoral nerve catheter was inserted with the aid of a nerve stimulator, and 20 ml of 0.5% bupivacaine was administered. The surgery was completed in a standard manner and the patients were randomized into three groups for the concentration of local anesthetic to continue the pain relief into the recovery phase. On awakening, all patients were determined to have a functioning femoral nerve catheter. Group 1 received 0.0625% (n = 8) bupivacaine, Group 2 0.125% (n = 9) bupivacaine, and Group 3 0.25% (n = 8) bupivacaine; all doses were initiated in a blinded manner at 0.12 ml/kg/hr. Patients also received intravenous patient-controlled analgesia with morphine via demand mode only, with a 1.0 mg dose and a 6 minute lock-out interval.

MEASUREMENTS AND MAIN RESULTS

Pain was determined at defined intervals by visual analog scale (VAS). Data collected included demographics, VAS scores, and total morphine administered. All patients were pain-free on emergence from general anesthesia. No patient required parenteral opioid for pain control while in the postanesthesia care unit. There were no significant differences in pain scores among groups, and average pain scores (2.5 to 4.0) indicate good pain control throughout the entire hospitalization. There were no complications.

CONCLUSIONS

Low concentrations of bupivacaine delivered via femoral nerve catheter after an established femoral nerve block can provide excellent postoperative pain control after ACL reconstruction.

Osteochondritis dissecans in a young pitcher: why early recognition matters

Osteochondritis dissecans of the humeral capitellum is an unusual, but not rare, complication of repetitive stress to the skeletally immature elbow. This case report of a Little League player demonstrates how untreated underlying osteochondrosis resulted in permanent disability. Radiographs are essential. The differential diagnosis includes infection, cysts, and Panner's disease. For nondisplaced fragments, rest is indicated until pain resolves and range of motion returns; surgery or arthroscopy may be needed to remove or repair displaced fragments.

Distribution of cellular repopulation and collagen synthesis in a canine anterior cruciate ligament autograft

Whether the central core of an anterior cruciate ligament autograft reconstruction is nutritionally compromised at a time when revascularization is known to be complete has not been determined by methods that detect matrix synthesis. In a canine model of anterior cruciate ligament reconstruction with patellar tendon autograft, the adequacy of the supply of metabolites for cellular matrix synthesis was determined by autoradiographic analysis. Total collagen synthesis and cellularity were also quantified. Total collagen synthesis was found to be significantly elevated (p = 0.014 by analysis of variance) in the ligament reconstructions as compared with normal anterior cruciate ligaments or patellar tendons but cellularity was not (p = 0.13 by analysis of variance). Autoradiography demonstrated even distribution of [3H]proline incorporation throughout the graft and normal tissue. When revascularization was complete there was an adequate supply of metabolites for cellular synthesis of protein macromolecules within all regions of the ligament reconstruction. At 3 months after reconstruction, the grafts were found to be actively remodeling their collagen matrix. Since the long-term function of an anterior cruciate ligament autograft is dependent on viable fibroblasts to maintain the collagen matrix the canine anterior cruciate ligament reconstruction contains living cells that are able to remodel the matrix under appropriate conditions.

Injuries about the hip and pelvis in the young athlete

Athletic injuries to the hip and pelvis in pediatric and adolescent athletes, although uncommon, may encompass a wide spectrum of entities. A familiarity with this spectrum and a high index of suspicion in the proper clinical setting will ensure timely diagnosis and help to facilitate implementation of a proper treatment plan thereby assuring safe return to play.

Comparison of collagen synthesis in the peripheral and central region of the canine meniscus

A comparison of collagen synthesis in the peripheral and central regions of the normal medial meniscus, the normal lateral meniscus, and the medial meniscus, three months after reconstruction of the anterior cruciate ligament (ACL), was performed in a canine model. Triangular-shaped explants were labeled in vitro with tritiated proline to compare collagen synthesis. Regional cellularity was also quantified. In the normal medial and lateral meniscus, cellularity was similar. Total collagen synthesis, as assessed by collagenase digestible material, was significantly elevated in the peripheral one-third of the medial meniscus versus the central region (paired t-test, p = 0.026). However, in the medial meniscus after ACL reconstruction, cellularity and total collagen synthesis were significantly higher in the peripheral one-third versus the contiguous central region. They were also elevated relative to the peripheral and central region of the normal medial and lateral meniscus (ANOVA, p < 0.05; Student-Neuman-Kuel test, p < 0.05). Thus, in the normal medial meniscus, the peripheral one-third may have an increased healing potential based on its increased ability to synthesize collagen. Furthermore, after ACL reconstruction, only the peripheral, and not the central, region of the canine meniscus responds to the altered mechanical and synovial environment by significantly increasing cellularity and collagen synthesis.

Autologous blood transfusion and intraoperative cell salvage in a patient with homozygous sickle cell disease

BACKGROUND

Autologous transfusion can eliminate the need for homologous transfusions. In addition, hypotensive anesthesia and devices that salvage red blood cells for return to the patient can reduce operative blood loss. However, blood from patients with sickle cell disease is difficult to store.

SUMMARY

A 16-year-old black girl with homozygous sickle cell disease needed surgery for progressive scoliosis. Her family's religious convictions precluded homologous transfusions. During surgery, 400 mL of autologous blood that had been successfully stored was transfused, as was 800 mL of blood salvaged using a cell-saving device, and 3800 mL of nonblood plasma expanders. Intravenous agents were used to maintain hypotension. However, following a rise in the patient's prothrombin and thromboplastin times, four units of homologous packed red cells were transfused with the permission of the patient's parents.

CONCLUSIONS

Patients with sickle cell disease can be given hypotensive anesthesia and autologous transfusions of blood donated before surgery and blood salvaged during surgery using a cell-saving device.

Prospective study of osseous, articular, and meniscal lesions in recent anterior cruciate ligament tears by magnetic resonance imaging and arthroscopy

Fifty-four patients with anterior cruciate ligament tears that were arthroscopically reconstructed within 3 months of initial injury were prospectively evaluated. Patients with grade 3 medial collateral ligament, lateral collateral ligament, or posterior cruciate ligament tears were excluded. Eighty percent of our patients had a bone bruise present on the magnetic resonance image, with 68% in the lateral femoral condyle. Two of the latter findings--an abnormal articular cartilage signal (P = 0.02) and a thin and impacted subchondral bone (P = 0.03)--had a significant relationship with injury to the overlying articular cartilage. Meniscal tears were found in 56% of the lateral menisci and 37% of the medial menisci. A significant association was present between bone bruising on the lateral femoral condyle and the lateral tibial plateau (P = 0.02). Results of our study support the concept that the common mechanism of injury to the anterior cruciate ligament involves severe anterior subluxation with impaction of the posterior tibia on the anterior femur. Determination of the significance of bone bruising, articular cartilage injury, or meniscal tears will require a long-term followup that includes evaluation for arthritis, stability, and function. These 54 patients represent the first cohort evaluated in this ongoing prospective clinical study.

Medial malleolar stress fractures in seven patients: review of the clinical and imaging features

Stress fractures of the medial malleolus were discovered in seven patients, five male and two female subjects aged 16-34 years. All except one were involved in running and jumping athletic activities. Gradual onset of pain over the medial malleolus occurred with repetitive activity. Focal intense increased uptake in the medial malleolus was present on bone scans. Conventional radiography and computed tomography demonstrated the presence of subtle fissures at the junction of the medial malleolus and the tibial plafond, and well-circumscribed lytic lesions were also seen in three patients. Two patients developed a complete fracture of the medial malleolus. Stress fractures of the medial malleolus should be suspected in patients involved in athletic and/or unusual activities who have experienced persistent and unexplained pain over the medial malleolus. Bone scans and radiographs should be obtained for diagnostic purposes in these patients.

Posterior shoulder instability. Surgical versus conservative results with evaluation of glenoid version

We conducted a retrospective study on 50 patients with recurrent posterior shoulder instability. Twenty-five patients were treated conservatively with a specific rehabilitation program strengthening the rotator cuff. The other 25 patients, who did not improve with rehabilitation, underwent surgical reconstruction, the majority of these being soft tissue repairs. Recurrence in the surgically treated group averaged 72% while that in the conservatively treated group was 96%. However, 50% of those patients treated surgically and 68% of those treated conservatively felt their symptoms were improved. In view of the high recurrence rate with soft tissue reconstruction, computed tomography scans were obtained to evaluate glenoid version. Those patients with posterior shoulder instability were found to have increased glenoid retroversion when compared to an uninjured population (P less than 0.05). Our conclusions based on this study were that 1) specific therapy in the form of rotator cuff strengthening should be the initial form of treatment in patients with posterior shoulder instability, 2) soft tissue surgery has a high rate of recurrence, 3) the return to sports is variable, 4) there appears to be an increased incidence of glenoid retroversion in this patient population, and 5) the incidence of posttraumatic arthritis is low.

Hand and wrist injuries in the preadolescent and adolescent athlete

In this time when physical prowess has been elevated to such a high level, the prepubescent and adolescent athlete have increased demands for performance placed on their immature musculoskeletal system. Although improved skills may result the athlete is exposed to more injury. Prompt, appropriate treatment of the injury with a controlled return to participation may prevent reinjury and disability. To this end, athletes, parents, coaches, trainers, and team physicians must maintain a close rapport for the benefit of the athlete.

How I Manage Shin Splints

Shin splints are a common problem for athletes whose sports involve a repeated, jarring impact to the leg. Often they are due to a change in activity level. Stopping the activity until the pain subsides, and then gradually working back up to the desired level is generally the best treatment and protection against recurrence.

Fiber-type specific caffeine sensitivities in normal human skinned muscle fibers

Caffeine sensitivity was studied in chemically skinned muscle fibers from vastus lateralis muscle obtained by biopsy during reconstructive knee surgery from 15 otherwise healthy young individuals. Muscle fiber type was determined by contracture occurring in strontium (slow-oxidative, type I fiber) or calcium (both type I and type II, fast glycolytic fiber) solutions and in several fibers after contracture testing by ATPase enzyme histochemistry. Caffeine sensitivity (mean +/- SD), defined as the threshold concentration inducing more than 10% of the maximal tension obtained with a calcium 3 x 10(-5) mM solution was 2.7 +/- 1.3 mM in 37 type I fibers, whereas it was 6.9 +/- 2.4 mM in 61 type II fibers. A paired t test showed a significantly increased sensitivity to caffeine in type I fibers (P less than 0.001) in 13 individuals in whom the two fiber types were identified. The mean (+/- SD) difference between type I and type II fibers was 4.1 +/- 1.9 mM. Type I fibers contracted with greater tension in response to the increasing concentration of caffeine than did type II fibers (P less than 0.05). These skinned fiber studies showed significantly different caffeine sensitivities between human type I and type II muscle fibers, as previously shown in animal muscles. The findings that human type I muscle fibers have higher caffeine sensitivity than type II muscle fibers should be helpful for the interpretation of the in vitro contracture test done in muscle strips containing type I and type II fibers in varying proportions.

Efficacy of intermittent epidural morphine following posterior spinal fusion in children and adolescents

Postoperative pain is a distressing and disabling feature of scoliosis surgery. Epidural morphine has recently been advocated to reduce the frequency and severity of postoperative pain in adults. A retrospective study of 35 patients was conducted to determine whether epidural administration of morphine is useful in the management of postoperative pain in children and adolescents following posterior spinal fusion. The derived data included dose and frequency of narcotic administration on the day of surgery and during the subsequent three days. On the first postoperative day, the total morphine given averaged only 16.4 mg in patients receiving epidural morphine compared to 27 mg in those receiving only conventional parenteral morphine. Similar significant differences persisted through the second postoperative day. Intermittent epidural injection of small doses of morphine can give satisfactory and prolonged analgesia for early postoperative pain management.

Experimental osteoarthritic articular cartilage is enriched in guanidine soluble type VI collagen

Experimental osteoarthritis was surgically induced in the right knee joint of dogs; the left knee served as a control. Articular cartilage was extracted with 4 M guanidinium chloride, 0.05 M sodium acetate, pH 6.0, containing proteinase inhibitors and the proteins purified by associative CsCl density gradient centrifugation. Equal quantities of protein were electrophoresed in agarose-acrylamide gradient gels and the high molecular weight type VI collagen bands detected in immunoblots with a polyclonal antiserum. Type VI collagen bands between 185 and 220 kDa were evident in the pathological specimens of dogs sacrificed 3, 5, and 7 months after surgery and were either absent or only very weakly visible in the controls. These results demonstrate that experimental osteoarthritic cartilage is enriched in 4 M guanidine-soluble type VI collagen.

Isobutyl cyanoacrylate as a soft tissue adhesive. An in vitro study in the rabbit Achilles tendon

Cyanoacrylates (CAs) are biodegradable, bacteriostatic, and hemostatic adhesives. CAs have been used in medical applications, but with adverse effects, including excessive inflammatory reaction and neural toxicity. Isobutyl CA (ICA) appears more biocompatible, with a long half-life that may be ideal for a soft tissue adhesive. The rabbit Achilles tendon was chosen to test (ICA), and a special muscle-freezing clamp to test this model was designed. The tendons were sharply cut 2 cm proximal to their insertion and repaired in four groups. They were tested to failure on an Instron machine. The breaking strength of the repairs was then noted. Also, the breaking strength of several suture materials was tested. Four Achilles tendon repair groups were evaluated: ICA alone 9.03 newtons (NTS); 4-0 silk Kessler stitch, mean 12.9 NTS; Kessler stitch plus three simple stitches, mean 23.0 NTS; and a combination of (a) and (c)--i.e., suture and adhesive, mean 40.2 NTS. The intact Achilles tendon was tested with an average breaking strength of 317 NTS. The muscle-freezing clamp facilitated reasonable testing of this tendon repair. ICA alone exhibits reasonable strength in vitro and in combination with suture provides a stronger initial repair than either suture or adhesive alone.

Knee arthroscopy using local anesthetic

The purpose of this study was to examine the effectiveness and safety of local anesthetics (a mixture of lidocaine and bupivacaine) in knee arthroscopy. Local anesthetic agents were shown to be effective and safe, based on chart review and measurement of blood levels of the anesthetic drugs.

Graft tension in anterior cruciate ligament reconstruction. An in vivo study in dogs

The purpose of this study was to examine the effect of initial tensioning on the outcome of reconstruction of the ACL. The ACLs of 15 adult mongrel dogs were excised and reconstructed. In the first five dogs, the ACLs of both knees were reconstructed using the medial one-third of the patellar tendon. The graft was fixed under a tension of 1 N (0.22 pounds) in one knee and 39 N (8.8 pounds) in the opposite knee. In the remainder of the dogs, the reconstructions were augmented with Dacron prostheses. Tensioning of both graft components in the augmented reconstructions was either with 1 N in one knee and 39 N in the contralateral knee or disproportionate tensions of 1 N and 39 N applied to the autogenous material and to the prosthesis. Sacrifice was 3 months postsurgery and results were examined with microangiography/history and mechanical testing. In the reconstructions with the patellar tendon alone, the biologic study showed poor vascularity and focal myxoid degeneration within the graft pretensioned with a load of 39 N. In the augmented reconstructions, the knees in which both graft materials were fixed with 1 N tension showed the strongest and stiffest reconstruction at 3 months. The study suggests that minimal tension should be applied to the graft materials during surgical reconstruction of the ACL.

A biomechanical comparison of different surgical techniques of graft fixation in anterior cruciate ligament reconstruction

Different surgical methods of graft fixation in ACL reconstruction were examined to determine the effects on mechanical properties of the reconstructed ACL. Ten human cadavers were used in this study. Six different types of grafts were studied. The tendon grafts were removed from each cadaver and fixed to femurs and tibias as ACL substitutes with different surgical fixation methods, leaving femur-reconstructed graft-tibia preparations. The surgical techniques used were staple fixation, tying sutures over buttons, and screw fixation. In the latter, the screws were introduced through femoral and tibial drill holes from the outside in order to achieve interference fit as described by Lambert. Tensile testing demonstrated that the original ACL is significantly stronger than the graft used for reconstruction in linear load, stiffness, and maximum tensile strength. All of the failures of the reconstructed ACL grafts occurred at the fixation site, indicating that the mechanically weak link of the reconstructed graft is located at the fixation site. Among the different methods of fixation, one-third of the patellar tendon secured with a cancellous screw, especially with a custom designed large diameter screw, showed significantly higher values. Although many other factors affect the success of ACL reconstruction, our study indicates that the method of surgical fixation is the major factor influencing the graft's mechanical properties in the immediate postoperative period.

The syndrome of inappropriate antidiuretic-hormone secretion following spinal fusion

Ten adolescent and preadolescent patients who underwent posterior spinal fusion for idiopathic scoliosis or spondylolisthesis were examined for the presence or absence of the postoperative syndrome of inappropriate antidiuretic-hormone secretion. For each patient, levels of serum sodium, serum osmolality, urine sodium, urine osmolality, and serum antidiuretic hormone were obtained preoperatively and postoperatively. The investigation clearly showed that the syndrome occurred in each patient, with the level of serum antidiuretic hormone being highest within a few hours postoperatively. This resulted in a reduction of urinary output, the reduction being maximum on the day of operation and the output gradually rising to normal over the next three days. This syndrome and its associated low postoperative urinary output is common after spinal fusion and should be treated with restriction of fluids rather than administration of increased amounts of fluid.

Augmentation of anterior cruciate ligament reconstruction in dogs with prostheses of different stiffnesses

The purpose of this study was to investigate the biological and biomechanical properties of anterior cruciate ligament (ACL) reconstruction augmented with Dacron prostheses of three different stiffnesses. The ACLs of 36 adult mongrel dogs were removed and the ligament was reconstructed. In 18 dogs, one knee was reconstructed with patellar tendon alone, and the contralateral knee with Dacron augmented patellar tendon. In the remaining 18 dogs, reconstruction was with Dacron augmented patellar tendon with Dacron alone being used for the contralateral control knee. Death was 3 months after surgery, and the reconstructions were examined biologically and biomechanically. The mechanical data were compared with immediate postoperative data obtained from 45 reconstructed fresh cadaveric knees. Tensile testing demonstrated that an increase in failure load was found when the implanted patellar tendon graft was compared with the cadaveric reconstruction. The strength of the Dacron augmented reconstruction showed little change while the Dacron alone graft decreased in strength during the period of implantation. No clear difference was found between the performance of augmentation devices of different stiffnesses. Microangiography showed that grafts were totally revascularized in patellar tendon alone, but not well revascularized in Dacron augmented patellar tendon and Dacron alone reconstruction. The presence of the Dacron appeared to have an adverse effect on revascularization.

Anterior cruciate reconstruction using the Jones-Ellison procedure

We performed a follow-up study of forty consecutive combined Jones-Ellison anterior-cruciate reconstructions in a young, athletic population. The mean interval from injury to operation was 2.7 years. Preoperatively, all patients had a 3+ or 4+ pivot shift and instability. All but five patients had a meniscal tear, and thirty patients had arthritic changes in the knee at the time of operation. Postoperatively only four of the patients had any complaints of giving-way. Although thirty of the patients returned to their previous sports activities, only eight achieved the preinjury level of performance. Arthritic symptoms were present at operation in thirty patients, while thirty-four had no postoperative objective signs of pivot shift or instability.

Knee injuries in gymnastics

A review of injury patterns to the knee joint in gymnastics seen at our sport medicine clinic over a six and one-half year period reveals the patellofemoral pain syndrome to be more than twice as frequent as any other type of injury. Sprains are second in frequency but first in order of problems requiring emergency surgical treatment. The intensity of training correlates with the various overuse syndrome encountered, and the perfection of intricate routines and tricks can lead to significant injury of ligaments and menisci.

Dacron augmentation in anterior cruciate ligament reconstruction in dogs

Substitution of the central third of the patellar tendon for the deficient anterior cruciate ligament was performed in 12 dogs (24 knees). In one-half of the knees the patellar tendon grafts were "augmented" with a 4-mm woven Dacron graft. It was hypothesized that Dacron augmentation would protect the patellar tendon graft during its revascularization stages. This was not the case, however. Only once did a Dacron ligament graft demonstrate superiority over the nonaugmented graft; indeed, five of the augmented grafts performed significantly worse.

Ligamentous injuries of the knee

Among the most potentially debilitating injuries to the athlete's knee are those injuries involving the ligaments. The unhappy sequelae of instability and premature osteoarthritis may be avoided by prompt, accurate recognition of the injury, appropriate delivery of treatment, and subsequent maintenance of rehabilitation.

Soft playing splint for protection of significant hand and wrist injuries in sports

A simple custom-made soft splint has been devised to allow safe sports participation for significant hand and wrist injuries. Made from readily available materials, this "rubber splint" has been used successfully in 113 injuries reviewed in this report. This splint is a result of a modification of an original "Duke" splint described by Dobson, Davis, Lincoln, and Basset, (Exhibit at American Academy of Orthopaedic Surgeons, San Francisco, California, 1971) and the soft cast used at the University of Virginia by McCue and Gieck (personal communication).

A new technique for intraoperative monitoring of spinal cord function: multichannel recording of spinal cord and subcortical evoked potentials

A new technique for intraoperative monitoring of spinal cord function is described. Evoked potentials to peripheral nerve stimulation are recorded with interspinous ligament needles from below and from two or more levels above the surgery. Simultaneously subcortical potentials are recorded with scalp electrodes from cervical-scalp derivations. Simultaneous recordings from multiple levels (below and above the surgical procedure) permit reliable differentiation between technical problems and alteration of cord function due to the surgical procedure. The interspinous ligament technique for recording of spinal potentials has significant advantages over previous monitoring techniques. One case in which monitoring during surgery detected a reversible acute spinal cord dysfunction is described.

Origin of far-field subcortical potentials evoked by stimulation of the posterior tibial nerve

Evoked potentials to stimulation of posterior tibial nerves were recorded from cervical-scalp derivation (cervical electrode: surface electrode on spinal process of the fifth cervical vertebrae; scalp: vertex). Four subcortical potentials labeled as N24, P27, N30 and P32 were identified. Evidence indicating that these components are originated in the following structures is presented: N24, posterior columns at the level of C5; P27, high cervical posterior columns or brain stem; N30, medial lemniscus or thalamus; P32, thalamo-cortical radiations.

Results of infected total hip replacement arthroplasty

Postoperative infection following total hip replacement and the complications associated with the treatment regimens are unsolved problems. The long term results of resection arthroplasties for infection in the older, debilitated individuals are poor insofar as patients may be destined to be either on crutches or bedfast for the duration of their lives.

Sacral agenesis: a clinical evaluation of its management, heredity, and associated anomalies

In the child born with sacral agenesis, the management of arthrogrypotic-like deformities, spinal and multisystem abnormalities poses several problems to the orthopedist. A clinical evaluation was undertaken on 17 patients and available parents in an effort to define better the heredity and proper management of this disorder. Flexion contractures of the hips and knees adversely affect ambulation potential and are rather resistant to standard treatment. The presence of protective sensation and proprioception, though, warrants aggressive attempts at correction, Subtrochanteric amputations are not necessary to achieve a functional ambulator. Spinal-pelvic instability does not preclude functional ambulation. In fact, there may be some benefit in maintaining motion in this region. Abolishment of spinal-pelvic motion by surgical fusion in the presence of hip contractures could impair sitting ability and the ability to walk upright. Congenital vertebral anomalies in the remainder of the spine, including the neck, occurred in 12 patients. Four patients had idiopathic-like curves. Only one patient had a normal spin above the level of agenesis. From an analysis of families, there was no obvious genetic association. Finally, the high frequency of multisystem associated congential abnormalities will necessitate a team approach to these patients.

Effects of synovial fluid on fibroblasts in tissue culture

The ability of the torn anterior cruciate ligament of the knee to heal is unpredictable, despite early surgical repair. A popular explanation has been that synovial fluid inhibits ligament healing. Other variables of ligament healing could reside with the fibroblasts, themselves, from different ligaments. With the use of tissue culture techniques, populations of fibroblasts were cultured from human anterior cruciate ligaments, deep and superficial medial collateral ligaments of the knee. Growth of fibroblasts from the anterior cruciate ligament was always diminished when exposed to synovial fluid and, on the average, plating efficiency was reduced by 46% when the culture medium contained synovial fluid. Growth rates demonstrated that fibroblasts from the superficial medial collateral ligament grew an average of 35% more than the others. Information gained from this study provides some data to explain the clinical frustration of the torn anterior cruciate ligament. The combination of synovial fluid inhibition of cell proliferation and the variable growth rates of fibroblasts, may explain the unsatisfactory healing of cruciate ligaments.