Thursday, 8 March 2007
Effects of Low-Intensity Pulsed Ultrasound on Tendon–Bone Healing in an Intra-articular Sheep Knee Model
William R. Walsh, Ph.D.a, Paul Stephens, M.D.a, Frank Vizesi, M.S.a, Warwick Bruce, M.D.a, James Huckle, Ph.D.b, Yan Yu, Ph.D.a
Purpose: This study reports the mechanical and histologic properties of intra-articular tendon–bone healing with the application of low-intensity pulsed ultrasound (LIPUS) in an ovine knee model.
Methods: A single digital extensor tendon autograft from the right hoof was used as the graft in 89 adult sheep. Femoral fixation was achieved with an EndoButton (Smith & Nephew Endoscopy, Andover, MA) and tibial fixation by tying over a bony post. LIPUS treatment was performed daily for 20 minutes over the femoral and tibial tunnels until sacrifice in all groups, apart from the 26-week group, which was treated only for the first 12 weeks. Histology was performed at 3, 6, 12, and 26 weeks. Mechanical testing was performed at 6, 12, and 26 weeks.
Results: The LIPUS-treated group showed increased cellular activity at the tendon–bone interface and general improvement in tendon–bone integration and vascularity. Stiffness and peak load were greater compared with the control group at 26 weeks after surgery (P < .05).
Conclusions: The application of LIPUS appears to improve healing at the tendon–bone interface for soft tissue grafts fixed with a suspensory fixation technique. Histology supports a benefit based on increased integration between tendon and bone and a biologically more active interface, which would account for the improved mechanical properties. Clinical Relevance: The indications of LIPUS may be expanded to include tendon–bone healing, for example, in anterior cruciate ligament reconstruction.
Wednesday, 7 March 2007
H-reflex latency and nerve root tension sign correlation in fluoroscopically guided, contrast-confirmed, translaminar lumbar epidural steroid-bupivaca
To examine the correlation between physical examination parameters, commonly referred to as “nerve root tension signs,” and H-reflex latency measurements both pre- and postepidural steroid-bupivacaine (Marcaine) injection, and to propose mechanisms of pain alleviation.
Patients received a fluoroscopically guided, contrast-confirmed, paramedian translaminar lumbar epidural injection of 120mg of methylprednisolone acetate (80mg/mL) and 2.0mL of .25% preservative-free Marcaine.
Main outcome measures
Seated slump testing (SST), straight-leg raising (SLR), and H-reflex latency were measured bilaterally both pre- and postinjection. Differences were measured by using the paired t test in an A-B design.
All SST of the affected (injected) side improved from pre- to postinjection, with 3 patients reporting discordant hamstring pain and 7 reporting no pain. SLR ability increased by an average of 29°±12°, corresponding to an average relative increase of 54% on the affected side. A statistically significant difference was found (Student t test, P=.02) between pre and post H-reflex latency on the affected side but not when comparing changes between affected and unaffected sides (Student t test, P=0.6).
Significant improvements in SST and SLR result from low volume epidural injection of Marcaine, with questionable prolongation of the H-reflex to the gastrocnemius-soleus complex on the affected side.
Krabak, Brian J. MD *+; Laskowski, Edward R. MD ++; Smith, Jay MD ++; Stuart, Michael J. MD [S]; Wong, Gilbert Y. MD [P]
Objective: To examine the potential contribution of neurologic influences on hamstring length during passive range of motion.
Design: Prospective study.
Settings: Academic sports medicine center.
Patients: 15 subjects undergoing arthroscopic surgery for unilateral knee injuries without previous injury to the contralateral knee.
Interventions: Subjects received: 1) spinal anesthesia with bupivacaine, 2) epidural anesthesia with lidocaine, 3) general anesthesia, or 4) femoral nerve block of injured leg only.
Main Outcome Measures: Noninjured leg popliteal angle preoperatively, intraoperatively under anesthesia, and postoperatively after recovery from anesthesia.
Results: The overall mean popliteal angle was 132.5 +/- 3.1[degrees] preoperatively, 134.31 +/- 11.6[degrees] intraoperatively, and 130.7 +/- 10.2[degrees] postoperatively. Overall, the intraoperative angle was significantly greater than the postoperative angle (p = 0.02). The mean change in popliteal angle was 8.1 +/- 2.2[degrees] (Group 1), -0.4 +/- 1.9[degrees] (Group 2), 0.9 +/- 1.4[degrees] (Group 3), and -2.4 +/- 3.8[degrees] (Group 4). There was no significant change in pre- to postoperative popliteal angle in relation to postoperative pain. Females had a greater mean popliteal angle (139.84[degrees]) compared with males (128.84[degrees]) (p = 0.04).
Clinical Relevance: Understanding the neuromuscular influences on muscle flexibility will assist in the development of new rehabilitative and injury preventative techniques.
Conclusion: The present pilot study implicates neural contributions to muscle flexibility. Further studies are needed to delineate the relative contributions of neural and muscular components and to facilitate new techniques in the rehabilitation and prevention of injury.
Vijay Vad, MD, Assistant Professor in Rehabilitation Medicine,
The case histories showed the following characteristics for all of the players. They noted the onset of pain while lunging for a stroke, with the onset of hamstring pain on the ipsilateral side of their dominant arm. None had any low back or buttock pain. The pain at the muscle-tendon junction of the hamstring worsened with continued lunging as well as with bending and prolonged sitting.
Physical examination showed only mild to moderate pain reproduction with deep palpation, as well as with resisted hamstring manual muscle testing. The patients had L5 myotome weakness.
MRI of the lumbar spine was ordered to rule out the lumbar spine as the aetiology of the chronic hamstring pain. MRI showed an L4-L5 disc bulge without any nerve root compression.
The results of nerve conduction studies were normal, but the needle examination revealed spontaneous activity at the L5 myotome of the symptomatic limb.
At this point, the players had a series of L5 selective nerve root epidural injections (Ref. 1) performed under fluoroscopy (average of 1.4 injections, range of 1-3). This was combined with daily use at night of a back cryobrace combined with a 5-stage lumbar stabilisation programme using aqua-therapy (Ref. 2). At an average of eight weeks after the first injection, all players returned to pre-injury level of tennis competition.
`Chronic hamstring strain’ is actually a chemical radiculitis from an L4-L5 disc bulge. The chemical irritation of the nerve root from the disc nucleus pulposus can manifest itself only at the muscle-tendon junction at times without any back or buttock pain. Increased pain with prolonged sitting can also lead to a suspicion of a disc causing nerve root irritation.
The transforaminal epidural injections under fluoroscopy, which are a much more precise form of the old epidural technique, have the advantage of precisely delivering the medication at the nerve-disc interphase where the pathology lies, while minimising nerve root injury or dural puncture incidence. These more exotic epidurals produced a 75% success rate in a retrospective study (Ref. 1) and 84% success rate in a prospective study at our institution, with long-lasting relief of pain when combined with a precise rehabilitation program.
The goal of rehabilitation is to gradually restore the delicate balance between flexibility, strength and endurance. The rehabilitation programme is carried out in four phases. In the early stages of phase1, aqua-therapy is used in combination with isometric strengthening and stretching. Phase 2 emphasises non-weight bearing, concentric strengthening. Phase 3 emphasises functional weight-bearing eccentric strengthening. The last phase, Phase 4, focuses on sports-specific training.
Ref. 1. Vad, V. et al. Fluoroscopic transforaminal lumbar epidural steroids: An Outcome Study. Arch. of Phys. Med. Rehabil. 79: 1362-1366, 1998Ref. 2. Vad, V. et al. Segmental instability: rehabilitation considerations. Seminars in Spine Surgery 8: 1-8, 1996.
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