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.

Meniscus treatment and age associated with narrower radiographic joint space width 2-3 years after ACL reconstruction: data from the MOON onsite cohort.

OBJECTIVE: To identify risk factors for radiographic signs of post-traumatic osteoarthritis (OA) 2-3 years after anterior cruciate ligament (ACL) reconstruction through multivariable analysis of minimum joint space width (mJSW) differences in a specially designed nested cohort. METHODS: A nested cohort within the Multicenter Orthopaedic Outcomes Network (MOON) cohort included 262 patients (148 females, average age 20) injured in sport who underwent ACL reconstruction in a previously uninjured knee, were 35 or younger, and did not have ACL revision or contralateral knee surgery. mJSW on semi-flexed radiographs was measured in the medial compartment using a validated computerized method. A multivariable generalized linear model was constructed to assess mJSW difference between the ACL reconstructed and contralateral control knees while adjusting for potential confounding factors. RESULTS: Unexpectedly, we found the mean mJSW was 0.35 mm wider in ACL reconstructed than in control knees (5.06 mm (95% CI 4.96-5.15 mm) vs 4.71 mm (95% CI 4.62-4.80 mm), P < 0.001). However, ACL reconstructed knees with meniscectomy had narrower mJSW compared to contralateral normal knees by 0.64 mm (95% C.I. 0.38-0.90 mm) (P < 0.001). Age (P < 0.001) and meniscus repair (P = 0.001) were also significantly associated with mJSW difference. CONCLUSION: Semi-flexed radiographs can detect differences in mJSW between ACL reconstructed and contralateral normal knees 2-3 years following ACL reconstruction, and the unexpected wider mJSW in ACL reconstructed knees may represent the earliest manifestation of post-traumatic osteoarthritis and warrants further study.

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.

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.

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.