Quadriceps strength to body weight ratio is a significant indicator for initiating jogging after anterior cruciate ligament reconstruction.

BACKGROUND: Quadriceps strength recovery after anterior cruciate ligament (ACL) reconstruction is an important criterion for progress in rehabilitation and return to sports. The purpose of this study was to determine whether quadriceps strength to body weight ratio (QS/BW) is a significant indicator for initiating jogging after ACL reconstruction. METHODS: Isokinetic quadriceps strength at 60°/s was measured and a jogging trial was completed 3 months after ACL reconstruction with hamstring tendon autograft in 83 patients (36 male, 47 female; mean age, 26.6 ± 12.4 years). Based on the jogging trial results, patients were assigned to either a successful jogging group (mean velocity ≥ 9 km/h) or an unsuccessful jogging group (mean velocity < 9 km/h). The association between QS/BW and successful jogging after surgery was investigated by multivariate logistic regression analysis and the cut-off value was determined by receiver operating characteristic analysis. RESULTS: Forty-four patients (53.0%) were assigned to the successful jogging group and 39 (47.0%) to the unsuccessful jogging group. QS/BW was independently associated with initiating jogging 3 months after surgery. The cut-off value of QS/BW for successful jogging was 1.45 Nm/kg (area under the curve = 0.94; sensitivity = 88.6%, specificity = 87.2%). All of the patients who initiated jogging with QS/BW of > 1.45 Nm/kg at 3 months returned to sports without recurrence or contralateral injury by 10 months after surgery. CONCLUSIONS: QS/BW is a significant indicator for safely initiating jogging 3 months after ACL reconstruction. The cut-off value of QS/BW for initiating jogging was 1.45 Nm/kg.

CT-based morphological assessment of the hip joint in Japanese patients: association with radiographic predictors of femoroacetabular impingement.

AIMS: Femoroacetabular impingement (FAI) has been highlighted and well documented primarily in Western countries and there are few large studies focused on FAI-related morphological assessment in Asian patients. We chose to investigate this subject. PATIENTS AND METHODS: We assessed the morphology of the hip and the prevalence of radiographic FAI in Japanese patients by measuring predictors of FAI. We reviewed a total of 1178 hips in 695 men and 483 women with a mean age of 58.2 years (20 to 89) using CT images that had been obtained for reasons unrelated to symptoms from the hip. We measured the lateral centre edge angle, acetabular index, crossover sign, alpha angle and anterior femoral head-neck offset ratio. RESULTS: A total of 441 hips (37.4%) had pincer-type deformity (41.7% men, 31.3% women) and 534 (45.3%) had cam-type deformity (54.4% men, 32.3% women). Moreover, 773 hips (65.6%) had at least one parameter that predisposes to FAI (74.0% men, 53.6% women) and 424 hips (36.0%) had two or more parameters (43.6% men, 25.0% women). CONCLUSION: The prevalence of radiographic FAI was common in Japanese patients who are generally considered to have dysplastic hips. Cite this article: Bone Joint J 2016;98-B:1167-74.

Fracture of a persistent olecranon physis in an adult.

A persistent olecranon physis is relatively rare; a fracture through the persistent olecranon physis in an adult is particularly rare. Little is known about the pathology of this disease. We report a case of a 36-year-old man presenting with right elbow pain after he had slipped and hit his elbow, with a history of a persistent symptomatic olecranon physis when he was a junior high school baseball player. He had been diagnosed with a fracture through a persistent olecranon physis by another doctor. Ten weeks after the injury, an iliac autograft was inserted and internal fixation was achieved with Kirschner wires and a figure-of-eight tension band in our hospital. Histologically, a fracture passed through the persistent physis cartilage and degeneration of the remnant of the physis was observed. The remnant of the physis at the olecranon side had not been replaced by new bone, though the physis at the distal ulnar was nearly replaced by new bone. The patient returned to work without experiencing pain or limitation in the range of motion 6 months after the operation. Radiographic evidence of bone union was seen after removal of internal fixation at the 13-month follow-up.

High incidence of acute traumatic spinal cord injury in a rural population in Japan in 2011 and 2012: an epidemiological study.

STUDY DESIGN: Retrospective questionnaire-based epidemiological study. BACKGROUND: Physicians treating acute traumatic spinal cord injury (SCI) in Japan noticed an increased occurrence of cervical SCI without skeletal injury. OBJECTIVE: To elucidate the precise epidemiology of acute cervical SCI with the aim of planning a prevention program. METHODS: Questionnaires were posted to all hospitals in Tokushima prefecture (around 780,000 inhabitants) to investigate the annual incidence of SCI in 2011 and 2012. RESULTS: The response rate was 79% in 2011 and 64% in 2012. The returned questionnaires reported on 95 patients in 2011 and 91 patients in 2012, with a mean age of 67.6 and 64.3 years and an annual incidence (per million population) of 121.4 and 117.1, respectively. More than two-thirds of the cases suffered cervical SCI without skeletal injury, and 61% of these were categorized as Frankel D neurological deficits due to low-energy impact as the main cause. CONCLUSION: The incidence of incomplete cervical SCI does appear to be increasing, and significant regional differences in the incidence of cervical SCI exist across Japan. We speculate that factors other than age are contributing to this increase.

Minimally invasive removal of a recurrent lumbar herniated nucleus pulposus by the small incised microendoscopic discectomy interlaminar approach.

In this report, we introduce two cases of recurrent herniated nucleus pulposus (HNP) at L5-S1 that were successfully removed using the small incised microendoscopic discectomy (sMED) technique, proposed by Dezawa and Sairyo in 2011. sMED was performed via the interlaminar approach with a percutaneous endoscope. The patients had previously underdone microendoscopic discectomy for HNP. For the recurrent HNP, the sMED interlaminar approach was selected because the HNP occurred at the level of L5-S1; the percutaneous endoscopic transforaminal approach was not possible for anatomical reasons. To perform sMED via the interlaminar approach, we employed new, specially made devices to enable us to use this technique. In conclusion, sMED is the most minimally invasive approach available for HNP, and its limitations have been gradually eliminated with the introduction specially made devices. In the near future, percutaneous endoscopic surgery could be the gold standard for minimally invasive disc surgery.

Endoscopic removal of herniated nucleus pulposus migrated dorsally to the dural sac.

A herniated nucleus pulposus (HNP) migrated dorsally to the dural sac is a rare condition. Here, we present a case, in which the HNP was removed with minimally invasive spinal endoscopy. A 54-year-old man presented complaining of left leg pain and paresis. Neurologic findings and an MRI suggested an epidural tumor or a dorsally migrated HNP compressing the S1 nerve root and dural sac. With a spinal endoscope, careful laminotomy of caudal L5 and cranial S1 was made. En bloc flavectomy exposed a mass covered with a thin capsule. The mass was identified as a dorsally migrated HNP. After complete HNP fragment removal, the dural sac and S1 nerve root were decompressed. Immediately postoperative, the leg pain subsided and motor function normalized, although the patient complained of numbness at the S1 dermatome area. In summary, a large HNP that had migrated dorsally to the dural sac was successfully removed endoscopically.

New minimally invasive discectomy technique through the interlaminar space using a percutaneous endoscope.

INTRODUCTION: The serial dilating technique used to access herniated discs at the L5-S1 space using percutaneous endoscopic discectomy (PED) via an 8 mm skin incision can possibly injure the S1 nerve root. In this paper, we describe in detail a new surgical procedure to safely access the disc and to avoid the nerve root damage. This small-incision endoscopic technique, small-incision microendoscopic discectomy (sMED), mimics microendoscopic discectomy and applies PED. MATERIALS AND SURGICAL TECHNIQUE: The sMED approach is similar to the well-established microendoscopic discectomy technique. To secure the surgical field, a duckbill-type PED cannula is used. Following laminotomy of L5 using a high-speed drill, the ligamentum flavum is partially removed using the Kerrison rongeur. Using the curved nerve root retractor, the S1 nerve root is gradually and gently moved caudally. Following the compete retraction of the S1 nerve root to the caudal side of the herniated nucleus pulposus (HNP), the nerve root is retracted safely medially and caudally using the bill side of the duckbill PED cannula. Next, using the HNP rongeur for PED, the HNP is removed piece by piece until the nerve root is decompressed. A total of 30 patients with HNP at the L5-S1 level underwent sMED. In all cases, HNP was successfully removed and patients showed improvement following surgery. Only one patient complained of moderate radiculopathy at the final visit. No complications were encountered. DISCUSSION: We introduced a minimally invasive technique to safely remove HNP at the L5-S1 level. sMED is possibly the least invasive technique for HNP removal at the L5-S1 level.

Complications of endoscopic lumbar decompression surgery.

BACKGROUND: Endoscopic lumbar decompression is useful for the treatment of various spinal conditions and is being performed in an increasing number of patients worldwide. We reviewed the surgery-related complications in patients who underwent endoscopic surgery and discuss the learning curve for this procedure. METHODS: Since the first case in August 2000, a total of 138 patients have undergone endoscopic posterior decompression surgery. Of these, there were 74 patients with Herniated Nucleus Pulposus (HNP), 57 with Lumbar Canal Stenosis (LCS), and 7 with other conditions. From 2003 to 2005, the senior surgeon took a sabbatical, and no endoscopic surgery was conducted. We divided the cases based on the date of surgery: there were 62 patients in the early (E) group (before September 2003), and 76 in the late (L) group (from January 2006 to April 2008). We compared the incidence of surgery-related complications between 2 disease types as well as between the E and L groups. RESULTS: We encountered 11 complications, which included 6 dural tears, 2 post-surgical hematomas, 2 neural complications and 1 fracture of the inferior articular process. The incidence of surgery-related complications was 8.6%. The incidences of complications were 8.1% and 9.3% for HNP and LCS, respectively, and 11.3%, and 5.3% in the E and L groups, respectively. The incidence was particularly high (16.7%) in the E group with LCS. CONCLUSION: There is a steep learning curve for endoscopic surgery. Based on the data, surgeons should start performing endoscopic techniques for LCS after gaining enough experience of endoscopic surgery for HNP.

Spondylolysis originates in the ventral aspect of the pars interarticularis: a clinical and biomechanical study.

Lumbar spondylolysis is a stress fracture of the pars interarticularis. We have evaluated the site of origin of the fracture clinically and biomechanically. Ten adolescents with incomplete stress fractures of the pars (four bilateral) were included in our study. There were seven boys and three girls aged between 11 and 17 years. The site of the fracture was confirmed by axial and sagittal reconstructed CT. The maximum principal tensile stresses and their locations in the L5 pars during lumbar movement were calculated using a three-dimensional finite-element model of the L3-S1 segment. In all ten patients the fracture line was seen only at the caudal-ventral aspect of the pars and did not spread completely to the craniodorsal aspect. According to the finite-element analysis, the higher stresses were found at the caudal-ventral aspect in all loading modes. In extension, the stress was twofold higher in the ventral than in the dorsal aspect. Our radiological and biomechanical results were in agreement with our clinical observations.

Minimally invasive endoscopic bilateral decompression with a unilateral approach (endo-BiDUA) for elderly patients with lumbar spinal canal stenosis.

OBJECTIVES: Endoscopic spinal surgery has become increasingly common year for year because it is a minimally invasive procedure. In our hospital, we introduced endoscopic bilateral decompression with a unilateral approach (endo-BiDUA) in 2006. In this paper, we review clinically and radiographically the elderly patients who underwent the endo-BiDUA. METHODS: Fifteen patients aged over 65 years were included in this review. They had undergone endo-BiDUA between January 2006 and July 2008. Operation time, blood loss, complications, clinical outcome using the Japanese Orthopedic Association (JOA) score, and enlargement ratio of the dural tube on magnetic resonance imaging (MRI), were evaluated. RESULTS: The mean operation time per level of endo-BiDUA was 144 min. Blood loss was about 60.2 mL. One patient had a post-surgical hematoma and required an additional laminectomy and removal of the hematoma 2 days after the surgery. No other complications such as dural tear, nerve root injury, or infection were encountered. All patients but one, who had a post-surgical hematoma, could start walking within 2 days following the surgery. Before surgery, the mean JOA score was 17.0 and it improved to about 23.3 after the surgery. The area of the dural tube increased to 408.0% after the surgery (range: 211-774%). CONCLUSIONS: Endo-BiDUA facilitated the return of elderly patients with lumbar spinal canal stenosis to their original daily activities.

The effect of rheumatoid arthritis on the anatomy of the female cervical spine: a radiological study.

The effect of rheumatoid arthritis on the anatomy of the cervical spine has not been clearly documented. We studied 129 female patients, 90 with rheumatoid arthritis and 39 with other pathologies (the control group). There were 21 patients in the control group with a diagnosis of cervical spondylotic myelopathy, and 18 with ossification of the posterior longitudinal ligament. All had plain lateral radiographs taken of the cervical spine as well as a reconstructed CT scan. The axial diameter of the width of the pedicle, the thickness of the lateral mass, the height of the isthmus and internal height were measured. The transverse diameter of the transverse foramen (d1) and that of the spinal canal (d2) were measured, and the ratio d1/d2 calculated. The width of the pedicles and the thickness of the lateral masses were significantly less in patients with rheumatoid arthritis than in those with other pathologies. The area of the transverse foramina in patients with rheumatoid arthritis was significantly greater than that in the other patients. The ratio of d1 to d2 was not significantly different. A high-riding vertebral artery was noted in 33.9% of the patients with rheumatoid arthritis and in 7.7% of those with other pathologies. This difference was statistically significant. In the rheumatoid group there was a significant correlation between isthmus height and vertical subluxation and between internal height and vertical subluxation.

Conservative treatment of lumbar spondylolysis in childhood and adolescence: the radiological signs which predict healing.

It has been noted that bony union of a pars defect can be achieved in children if they wear a trunk brace. Our aim was to evaluate how the stage of the defect on CT and the presence or absence of high signal change in the adjacent pedicle on T2-weighted MRI were related to bony healing. We treated 23 children conservatively for at least three months. There were 19 boys and four girls with a mean age of 13.5 years (7 to 17). They were asked to refrain from sporting activity and to wear a Damen soft thoracolumbosacral type brace. There were 41 pars defects in 23 patients. These were classified as an early, progressive or terminal stage on CT. The early-stage lesions had a hairline crack in the pars interarticularis, which became a gap in the progressive stage. A terminal-stage defect was equivalent to a pseudarthrosis. On the T2-weighted MR scan the presence or absence of high signal change in the adjacent pedicle was assessed and on this basis the defects were divided into high signal change-positive or -negative. Healing of the defect was assessed by CT. In all, 13 (87%) of the 15 early defects healed. Of 19 progressive defects, only six (32%) healed. None of the seven terminal defects healed. Of the 26 high signal change-positive defects 20 (77%) healed after conservative treatment whereas none of the high signal change-negative defects did so. We concluded that an early-stage defect on CT and high signal change in the adjacent pedicle on a T2-weighted MR scan are useful predictors of bony healing of a pars defect in children after conservative treatment.

Minimally invasive excision of lumbar epidural lipomatosis using a spinal endoscope.

In this report, we describe the case of a patient with a long-term radiculopathy due to epidural lipomatosis at the L3-4 intervertebral disc level. The fatty tissue was located on the dorsal side of the dural sac in the spinal canal and compressed the dural sac. The fatty tissue was removed endoscopically. After surgery, the symptoms disappeared, and neurological deficits normalized. We would like to state that epidural lipomatosis is a good candidate for minimally invasive endoscopic surgery because of its anatomic location.

Callus formation during healing of the repaired tendon-bone junction. A rat experimental model.

This study was undertaken to elucidate the mechanism of biological repair at the tendon-bone junction in a rat model. The stump of the toe flexor tendon was sutured to a drilled hole in the tibia (tendon suture group, n = 23) to investigate healing of the tendon-bone junction both radiologically and histologically. Radiological and histological findings were compared with those observed in a sham control group where the bone alone was drilled (n = 19). The biomechanical strength of the repaired junction was confirmed by pull-out testing six weeks after surgery in four rats in the tendon suture group. Callus formation was observed at the site of repair in the tendon suture group, whereas in the sham group callus formation was minimal. During the pull-out test, the repaired tendon-bone junction did not fail because the musculotendinous junction always disrupted first. In order to understand the factors that influenced callus formation at the site of repair, four further groups were evaluated. The nature of the sutured tendon itself was investigated by analysing healing of a tendon stump after necrosis had been induced with liquid nitrogen in 16 cases. A proximal suture group (n = 16) and a partial tenotomy group (n = 16) were prepared to investigate the effects of biomechanical loading on the site of repair. Finally, a group where the periosteum had been excised at the site of repair (n = 16) was examined to study the role of the periosteum. These four groups showed less callus formation radiologically and histologically than did the tendon suture group. In conclusion, the sutured tendon-bone junction healed and achieved mechanical strength at six weeks after suturing, showing good local callus formation. The viability of the tendon stump, mechanical loading and intact periosteum were all found to be important factors for better callus formation at a repaired tendon-bone junction.

Locking of the metacarpophalangeal joint as a result of the shape of the metacarpal head in achondroplasia.

A 21 year-old woman with achondroplasia exhibited locking of the metacarpophalangeal joint of the right index finger which required surgery to release the joint. Locking was confirmed to be due to entrapment of the fan-like part of the radial collateral ligament on a metacarpal head prominence arising from epiphysial thickening.

Minimally invasive endoscopic removal of a herniated nucleus pulposus that had migrated to the S1 nerve root foramen.

In this report, we described an adult case with a lumbar herniated nucleus pulposus that had migrated to the S1 nerve root foramen from L5-S1 disc space. Endoscopically, the migrated mass was successfully removed after laminectomy at the S1 with a small skin incision of 20 mm in length. Unlike the other levels, the intraforaminally migrated mass along the S1 root can be excised without any removal of the facet joints; therefore, additional spinal fusion is not necessary. Thus, an S1 foraminal migrated mass can be a good surgical candidate for minimally invasive endoscopic surgery.

Minimally invasive technique for direct repair of the pars defects in young adults using a spinal endoscope: a technical note.

Pars defect (spondylolysis) of the lumbar spine can cause chronic low back pain, and it sometimes requires surgical intervention. Direct repair is selected for the surgery if young adult patients do not present significant disc degeneration and lumbar instability. In order to lessen damages of back muscles during surgery, we added the use of a spinal endoscope to the "Buck's screwing procedure" the direct repair. There are four steps in this procedure: 1) identification of the defect, 2) curettage (refresh) of the defect, 3) percutaneous insertion of the annulated screws and 4) cancellous bone grafting. All these steps can be done endoscopically. We treated 3 young adults--a baseball player, a professional cycle-racer and a sculptor--using this endoscopic procedure. There were no complications during or after the operation. Union was obtained in all defects within 3 months, and they returned to their previous activities within 6 months after the surgery.

Minimally invasive decompression for lumbar spinal canal stenosis in younger age patients could lead to higher stresses in the remaining neural arch -- a finite element investigation.

BACKGROUND AND PURPOSE: A young patient group with the symptoms of acquired spinal stenosis has been identified recently in the literature. The patients between 25-50 years of age were found to have signs of lumbar spinal stenosis because of degenerative spinal changes. Some of them were operated on using the same limited decompression approaches as the older patients. However, this group differs from the geriatric population due to the scarcity of remodeling degenerative signs at the spine. Therefore, the possible ligamentous laxity, facet joint degeneration or only the removal of some spinal structures could lead to the increased stresses in the remaining spinal arch and could have an unfavorable course of events after the procedure. A biomechanical study has been done using an experimentally validated finite element model (FEM) of the intact L3-S1 lumbar spine to elucidate the influence of the limited decompression on range of motion (ROM) and stress distribution on the neural arch in this patient group. METHODS: We simulated unilateral laminotomy L4 and medial facetectomy L4-5, medial facetectomy L4-5 and lateral fenestration of L5 pars interarticularis, combined transarticular lateral and medial approach with partial facetectomy L4-5, "port-hole" decompression at the L4 level, and hemilaminectomy L4 with medial facetectomy L4-5. The ROM and maximum von Mises stresses were analyzed in flexion, extension, lateral bending, and axial rotation in response to a 10.6 Nm moment with 400 N axial compression. The data were compared with the intact spine and hemilaminectomy L4 with medial facetectomy L4-5 models. RESULTS AND CONCLUSION: The investigation revealed almost the same ROM after simulation but a considerable increase in stresses at both the pars interarticularis and the inferior facet after limited decompressions, especially in extension and rotation to the contralateral side. Stresses at the contralateral L4 pedicle were highest after L4 hemilaminectomy and medial facetectomy L4-5. Due to the observed increases in stresses, the surgeon should be aware of the possibilities of stress-fractures in this patient group.