Postoperative stiffness and adhesion formation around repaired and immobilized Achilles tenotomies are prevented using a model of heat shock protein induction

Comparison of Large-Gauge Needle, Corneal Knife, and No. 11 Blade for Percutaneous Achillotomy

BACKGROUND

In the Ponseti technique, the residual equinus deformity is corrected with percutaneous tenotomy. This experimental study aimed to compare the safety and effectiveness of a large-gauge needle, a corneal knife, and a No. 11 blade in percutaneous achillotomy performed in rats.

METHODS

Ninety Achilles tendons of 45 Sprague-Dawley rats were analyzed, following division into three study groups. In the study, group I (needle), group II (corneal knife), and group III (No. 11 blade) were compared on the basis of bleeding, incision length, requirement for primary suture, range of motion, and resulting neurovascular injury at day 0. Moreover, the groups were compared in terms of range of motion, macroscopic and microscopic adhesions, and tenocyte morphology at days 21 and 42 postoperatively.

RESULTS

On day 0, one suture was required in group III, whereas in groups I and II, no sutures were required. Postoperative bleeding was greater in group III and similar in groups I and II. Neurovascular injury was not observed in any of the groups. Three incomplete tenotomies were observed in group III and one incomplete tenotomy was observed in group II. Importantly, all tenotomies were complete in group I. In all groups, the range of motion was similar. The macroscopic adhesion score revealed high adhesion in group III (P = .009). According to Tang's criteria, microscopic adhesion was significantly higher on day 21 in group III compared with the other groups (P <0.001). No significant differences were observed in tenocyte morphology based on the Bonar criteria (P = .850).

CONCLUSIONS

In the results obtained from this animal study, we observed less bleeding, less adhesion, and less incomplete tenotomy in the large-gauge needle and corneal knife groups compared with the No. 11 blade group during the percutaneous Achilles tenotomy performed in rats.

Thermal Preconditioning for Surgery: A Systematic Review

BACKGROUND

Optimising patients pre-operatively reduces the chance of complications. This may be achieved by preconditioning. Thermal preconditioning refers to the supraphysiological heating of organisms or specific organs prior to an environmental insult. This review explores the current application and efficacy of thermal preconditioning for surgery.

METHODS

A comprehensive search of Medline (via PubMed), Embase and the Cochrane library was performed. Only articles evaluating the use of supraphysiological heating prior to a surgical intervention were included. Qualitative syntheses of data were undertaken due to the heterogeneity of the studies. The quality of each article was appraised using risk of bias tools (Cochrane and SYRCLE).

RESULTS

The primary literature search returned 3175 articles. After screening and reviewing reference lists, 28 papers met the inclusion criteria. The majority of studies were performed in animals, with only three clinical trials. Although there was broad coverage of different surgical techniques, flap transfer was the most commonly performed procedure. Most studies demonstrated a beneficial effect of thermal preconditioning, ranging from increased joint mobility to improved flap or organ transplant survival rates. The quality of evidence was variable, with experimental animal studies limited by a lack of methodological detail.

CONCLUSIONS

Thermal preconditioning for surgery has been primarily investigated using animal models. A beneficial effect has been demonstrated in most cases, across specialties ranging from plastic to general surgery. Future studies should aim to assess the clinical significance through large multicentre randomised controlled trials.

Calcaneofibular Ligament Transfer for Recurrent Peroneal Tendon Subluxation in Pediatric and Young Adult Patients

BACKGROUND

Peroneal tendon subluxation is an uncommon cause of lateral ankle pain and instability but can be disabling for some young patients. Surgical management may be required to restore function for patients who fail nonoperative management. The purpose of this study was to determine the functional outcomes after surgical management of peroneal tendon subluxation in pediatric and adolescent patients.

METHODS

A retrospective review of patients presenting to our institution over a 10-year period yielded 18 cases of recurrent subluxation refractory to nonoperative management in 14 children or young adults (mean age 15.0 y). All patients failed nonoperative management and were treated operatively with isolated calcaneofibular ligament transfer to construct a new soft tissue restraint for the peroneal tendons. Patients were evaluated clinically and sent validated questionnaires, including the Foot and Ankle Ability Measure (FAAM) and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale.

RESULTS

All 18 ankles of 14 patients had minimum 2-year follow-up. Ten of 18 ankles (55.6%) returned the outcome surveys at an average of 5.7 years after the index procedure (range, 2. 0 to 9.7 y). The average FAAM activities of daily living score was 93.5 (±2.9) and the sports subscale was 77.8 (±6.1). The mean AOFAS subjective scaled score was 84.3 (±4.5). All patients returned to sports and recreational activity. Complications included 1 case of recurrent subluxation (1/18, 5.5%) treated with revision to a Chrisman-Snook procedure and 4 ankles (4/18, 22.2%) with stiffness or arthrofibrosis treated with a secondary procedure of peroneal tendon release or lysis of adhesions.

CONCLUSIONS

Surgical management with rerouting of the peroneal tendons under the calcaneofibular ligament appears to be safe and effective for young patients with chronic peroneal tendon subluxation. It provides a low rate of recurrent subluxation, excellent stability, and good long-term functional outcomes. However, the potential for postoperative stiffness appears to be a limitation to the procedure and necessitates aggressive physical therapy to maintain ankle motion.

LEVEL OF EVIDENCE

Level IV- retrospective case series.

Superimposed electrical stimulation improves mobility of pre-stiff thumbs after ulnar collateral ligament injury of the metacarpophalangeal joint: a randomized study

OBJECTIVE

This study aimed at testing the ability of the superimposed electrical stimulation technique to restore the mobility of pre-stiff thumbs after operative repair for rupture of the ulnar collateral ligament.

MATERIAL AND METHODS

Eight patients demonstrating a pre-stiff metacarpophalangeal joint were involved in two rehabilitation sessions of a counterbalanced design. In the voluntary contraction session, they performed 20min of repeated active flexions of the impaired metacarpophalangeal joint. In the superimposed electrical stimulation session, they performed 20min of percutaneous neuromuscular electrical stimulations which were superimposed to voluntary flexion.

RESULTS

Mean active range of motion improvement from pre- to post-session was significantly greater in the superimposed electrical stimulation condition compared to the voluntary contraction condition (11±5 deg versus 3±4 deg; P<0.01).

CONCLUSION

Superimposing electrical stimulation to voluntary contractions is an efficient technique to improve active range of motion of the pre-stiff metacarpophalangeal joint of the thumb.

The effect of thermal preconditioning of the limb on flexor tendon healing

Thermal preconditioning reduces inflammation by inducing cytoprotective heat shock proteins. We evaluated the role of limb thermal preconditioning in a rabbit model of flexor tendon repair. The treatment groups underwent limb preconditioning by elevating the limb temperature to 41.5 degrees C for 20 minutes. The animals were sacrificed three and six weeks after flexor tendon repair. Heat shock protein72 expression of the treated limb was measured at 18 hours. Macroscopic analysis demonstrated a significant decrease in adhesion formation in the three week treatment group. The inflammatory infiltrate was significantly reduced for both treatment groups. The difference in ultimate tensile strength was not significant. We conclude that thermal preconditioning of the limb before flexor tendon repair decreases inflammation and adhesion formation in a rabbit model and has the potential to improve clinical outcome of flexor tendon surgery.

Heat shock preconditioning reduces ischemic tissue necrosis by heat shock protein (HSP)-32-mediated improvement of the microcirculation rather than induction of ischemic tolerance

INTRODUCTION

Supraphysiologic stress induces a heat shock response, which may exert protection against ischemic necrosis. Herein we analyzed in vivo whether the induction of heat shock protein (HSP) 32 improves survival of chronically ischemic myocutaneous tissue, and whether this is based on amelioration of microvascular perfusion or induction of ischemic tolerance.

METHODS

The dorsal skin of mice was subjected to local heat preconditioning (n = 8) 24 hours before surgery. In additional heat-preconditioned animals (n = 8), HSP-32 was inhibited by tin-protoporphyrin-IX. Unconditioned animals served as controls (n = 8). A random-pattern myocutaneous flap was elevated in the back of the animals and fixed into a dorsal skinfold chamber. The microcirculation, edema formation, apoptotic cell death, and tissue necrosis were analyzed over a 10-day period using intravital fluorescence microscopy.

RESULTS

HSP-32 protein expression was observed only in heat-preconditioned but not in unconditioned flaps. Heat preconditioning induced arteriolar dilation, which was associated with a significant improvement of both arteriolar blood flow and capillary perfusion in the distal part of the flap. Further, heat shock reduced interstitial edema formation, attenuated apoptotic cell death, and almost completely abrogated the development of flap necrosis (4% +/- 1% versus controls: 53% +/- 5%; P[r] < 0.001). Most strikingly, inhibition of HSP-32 by tin-protoporphyrin-IX completely blunted the preconditioning-induced improvement of microcirculation and resulted in manifestation of 72% +/- 4% necrosis.

CONCLUSION

Local heat preconditioning of myocutaneous tissue markedly increases flap survival by maintaining adequate nutritive perfusion rather than inducing ischemic tolerance. The protection is caused by the increased arteriolar blood flow due to significant arteriolar dilation, which is mediated through the carbon monoxide-associated vasoactive properties of HSP-32.